drivers/ide/ide-tape.c

   1 /*
   2  * linux/drivers/ide/ide-tape.c         Version 1.19    Nov, 2003
   3  *
   4  * Copyright (C) 1995 - 1999 Gadi Oxman <gadio@netvision.net.il>
   5  *
   6  * $Header$
   7  *
   8  * This driver was constructed as a student project in the software laboratory
   9  * of the faculty of electrical engineering in the Technion - Israel's
  10  * Institute Of Technology, with the guide of Avner Lottem and Dr. Ilana David.
  11  *
  12  * It is hereby placed under the terms of the GNU general public license.
  13  * (See linux/COPYING).
  14  */
  15
  16 /*
  17  * IDE ATAPI streaming tape driver.
  18  *
  19  * This driver is a part of the Linux ide driver and works in co-operation
  20  * with linux/drivers/block/ide.c.
  21  *
  22  * The driver, in co-operation with ide.c, basically traverses the
  23  * request-list for the block device interface. The character device
  24  * interface, on the other hand, creates new requests, adds them
  25  * to the request-list of the block device, and waits for their completion.
  26  *
  27  * Pipelined operation mode is now supported on both reads and writes.
  28  *
  29  * The block device major and minor numbers are determined from the
  30  * tape's relative position in the ide interfaces, as explained in ide.c.
  31  *
  32  * The character device interface consists of the following devices:
  33  *
  34  * ht0          major 37, minor 0       first  IDE tape, rewind on close.
  35  * ht1          major 37, minor 1       second IDE tape, rewind on close.
  36  * ...
  37  * nht0         major 37, minor 128     first  IDE tape, no rewind on close.
  38  * nht1         major 37, minor 129     second IDE tape, no rewind on close.
  39  * ...
  40  *
  41  * Run linux/scripts/MAKEDEV.ide to create the above entries.
  42  *
  43  * The general magnetic tape commands compatible interface, as defined by
  44  * include/linux/mtio.h, is accessible through the character device.
  45  *
  46  * General ide driver configuration options, such as the interrupt-unmask
  47  * flag, can be configured by issuing an ioctl to the block device interface,
  48  * as any other ide device.
  49  *
  50  * Our own ide-tape ioctl's can be issued to either the block device or
  51  * the character device interface.
  52  *
  53  * Maximal throughput with minimal bus load will usually be achieved in the
  54  * following scenario:
  55  *
  56  *      1.      ide-tape is operating in the pipelined operation mode.
  57  *      2.      No buffering is performed by the user backup program.
  58  *
  59  * Testing was done with a 2 GB CONNER CTMA 4000 IDE ATAPI Streaming Tape Drive.
  60  *
  61  * Ver 0.1   Nov  1 95   Pre-working code :-)
  62  * Ver 0.2   Nov 23 95   A short backup (few megabytes) and restore procedure
  63  *                        was successful ! (Using tar cvf ... on the block
  64  *                        device interface).
  65  *                       A longer backup resulted in major swapping, bad
  66  *                        overall Linux performance and eventually failed as
  67  *                        we received non serial read-ahead requests from the
  68  *                        buffer cache.
  69  * Ver 0.3   Nov 28 95   Long backups are now possible, thanks to the
  70  *                        character device interface. Linux's responsiveness
  71  *                        and performance doesn't seem to be much affected
  72  *                        from the background backup procedure.
  73  *                       Some general mtio.h magnetic tape operations are
  74  *                        now supported by our character device. As a result,
  75  *                        popular tape utilities are starting to work with
  76  *                        ide tapes :-)
  77  *                       The following configurations were tested:
  78  *                              1. An IDE ATAPI TAPE shares the same interface
  79  *                                 and irq with an IDE ATAPI CDROM.
  80  *                              2. An IDE ATAPI TAPE shares the same interface
  81  *                                 and irq with a normal IDE disk.
  82  *                        Both configurations seemed to work just fine !
  83  *                        However, to be on the safe side, it is meanwhile
  84  *                        recommended to give the IDE TAPE its own interface
  85  *                        and irq.
  86  *                       The one thing which needs to be done here is to
  87  *                        add a "request postpone" feature to ide.c,
  88  *                        so that we won't have to wait for the tape to finish
  89  *                        performing a long media access (DSC) request (such
  90  *                        as a rewind) before we can access the other device
  91  *                        on the same interface. This effect doesn't disturb
  92  *                        normal operation most of the time because read/write
  93  *                        requests are relatively fast, and once we are
  94  *                        performing one tape r/w request, a lot of requests
  95  *                        from the other device can be queued and ide.c will
  96  *                        service all of them after this single tape request.
  97  * Ver 1.0   Dec 11 95   Integrated into Linux 1.3.46 development tree.
  98  *                       On each read / write request, we now ask the drive
  99  *                        if we can transfer a constant number of bytes
 100  *                        (a parameter of the drive) only to its buffers,
 101  *                        without causing actual media access. If we can't,
 102  *                        we just wait until we can by polling the DSC bit.
 103  *                        This ensures that while we are not transferring
 104  *                        more bytes than the constant referred to above, the
 105  *                        interrupt latency will not become too high and
 106  *                        we won't cause an interrupt timeout, as happened
 107  *                        occasionally in the previous version.
 108  *                       While polling for DSC, the current request is
 109  *                        postponed and ide.c is free to handle requests from
 110  *                        the other device. This is handled transparently to
 111  *                        ide.c. The hwgroup locking method which was used
 112  *                        in the previous version was removed.
 113  *                       Use of new general features which are provided by
 114  *                        ide.c for use with atapi devices.
 115  *                        (Programming done by Mark Lord)
 116  *                       Few potential bug fixes (Again, suggested by Mark)
 117  *                       Single character device data transfers are now
 118  *                        not limited in size, as they were before.
 119  *                       We are asking the tape about its recommended
 120  *                        transfer unit and send a larger data transfer
 121  *                        as several transfers of the above size.
 122  *                        For best results, use an integral number of this
 123  *                        basic unit (which is shown during driver
 124  *                        initialization). I will soon add an ioctl to get
 125  *                        this important parameter.
 126  *                       Our data transfer buffer is allocated on startup,
 127  *                        rather than before each data transfer. This should
 128  *                        ensure that we will indeed have a data buffer.
 129  * Ver 1.1   Dec 14 95   Fixed random problems which occurred when the tape
 130  *                        shared an interface with another device.
 131  *                        (poll_for_dsc was a complete mess).
 132  *                       Removed some old (non-active) code which had
 133  *                        to do with supporting buffer cache originated
 134  *                        requests.
 135  *                       The block device interface can now be opened, so
 136  *                        that general ide driver features like the unmask
 137  *                        interrupts flag can be selected with an ioctl.
 138  *                        This is the only use of the block device interface.
 139  *                       New fast pipelined operation mode (currently only on
 140  *                        writes). When using the pipelined mode, the
 141  *                        throughput can potentially reach the maximum
 142  *                        tape supported throughput, regardless of the
 143  *                        user backup program. On my tape drive, it sometimes
 144  *                        boosted performance by a factor of 2. Pipelined
 145  *                        mode is enabled by default, but since it has a few
 146  *                        downfalls as well, you may want to disable it.
 147  *                        A short explanation of the pipelined operation mode
 148  *                        is available below.
 149  * Ver 1.2   Jan  1 96   Eliminated pipelined mode race condition.
 150  *                       Added pipeline read mode. As a result, restores
 151  *                        are now as fast as backups.
 152  *                       Optimized shared interface behavior. The new behavior
 153  *                        typically results in better IDE bus efficiency and
 154  *                        higher tape throughput.
 155  *                       Pre-calculation of the expected read/write request
 156  *                        service time, based on the tape's parameters. In
 157  *                        the pipelined operation mode, this allows us to
 158  *                        adjust our polling frequency to a much lower value,
 159  *                        and thus to dramatically reduce our load on Linux,
 160  *                        without any decrease in performance.
 161  *                       Implemented additional mtio.h operations.
 162  *                       The recommended user block size is returned by
 163  *                        the MTIOCGET ioctl.
 164  *                       Additional minor changes.
 165  * Ver 1.3   Feb  9 96   Fixed pipelined read mode bug which prevented the
 166  *                        use of some block sizes during a restore procedure.
 167  *                       The character device interface will now present a
 168  *                        continuous view of the media - any mix of block sizes
 169  *                        during a backup/restore procedure is supported. The
 170  *                        driver will buffer the requests internally and
 171  *                        convert them to the tape's recommended transfer
 172  *                        unit, making performance almost independent of the
 173  *                        chosen user block size.
 174  *                       Some improvements in error recovery.
 175  *                       By cooperating with ide-dma.c, bus mastering DMA can
 176  *                        now sometimes be used with IDE tape drives as well.
 177  *                        Bus mastering DMA has the potential to dramatically
 178  *                        reduce the CPU's overhead when accessing the device,
 179  *                        and can be enabled by using hdparm -d1 on the tape's
 180  *                        block device interface. For more info, read the
 181  *                        comments in ide-dma.c.
 182  * Ver 1.4   Mar 13 96   Fixed serialize support.
 183  * Ver 1.5   Apr 12 96   Fixed shared interface operation, broken in 1.3.85.
 184  *                       Fixed pipelined read mode inefficiency.
 185  *                       Fixed nasty null dereferencing bug.
 186  * Ver 1.6   Aug 16 96   Fixed FPU usage in the driver.
 187  *                       Fixed end of media bug.
 188  * Ver 1.7   Sep 10 96   Minor changes for the CONNER CTT8000-A model.
 189  * Ver 1.8   Sep 26 96   Attempt to find a better balance between good
 190  *                        interactive response and high system throughput.
 191  * Ver 1.9   Nov  5 96   Automatically cross encountered filemarks rather
 192  *                        than requiring an explicit FSF command.
 193  *                       Abort pending requests at end of media.
 194  *                       MTTELL was sometimes returning incorrect results.
 195  *                       Return the real block size in the MTIOCGET ioctl.
 196  *                       Some error recovery bug fixes.
 197  * Ver 1.10  Nov  5 96   Major reorganization.
 198  *                       Reduced CPU overhead a bit by eliminating internal
 199  *                        bounce buffers.
 200  *                       Added module support.
 201  *                       Added multiple tape drives support.
 202  *                       Added partition support.
 203  *                       Rewrote DSC handling.
 204  *                       Some portability fixes.
 205  *                       Removed ide-tape.h.
 206  *                       Additional minor changes.
 207  * Ver 1.11  Dec  2 96   Bug fix in previous DSC timeout handling.
 208  *                       Use ide_stall_queue() for DSC overlap.
 209  *                       Use the maximum speed rather than the current speed
 210  *                        to compute the request service time.
 211  * Ver 1.12  Dec  7 97   Fix random memory overwriting and/or last block data
 212  *                        corruption, which could occur if the total number
 213  *                        of bytes written to the tape was not an integral
 214  *                        number of tape blocks.
 215  *                       Add support for INTERRUPT DRQ devices.
 216  * Ver 1.13  Jan  2 98   Add "speed == 0" work-around for HP COLORADO 5GB
 217  * Ver 1.14  Dec 30 98   Partial fixes for the Sony/AIWA tape drives.
 218  *                       Replace cli()/sti() with hwgroup spinlocks.
 219  * Ver 1.15  Mar 25 99   Fix SMP race condition by replacing hwgroup
 220  *                        spinlock with private per-tape spinlock.
 221  * Ver 1.16  Sep  1 99   Add OnStream tape support.
 222  *                       Abort read pipeline on EOD.
 223  *                       Wait for the tape to become ready in case it returns
 224  *                        "in the process of becoming ready" on open().
 225  *                       Fix zero padding of the last written block in
 226  *                        case the tape block size is larger than PAGE_SIZE.
 227  *                       Decrease the default disconnection time to tn.
 228  * Ver 1.16e Oct  3 99   Minor fixes.
 229  * Ver 1.16e1 Oct 13 99  Patches by Arnold Niessen,
 230  *                          niessen@iae.nl / arnold.niessen@philips.com
 231  *                   GO-1)  Undefined code in idetape_read_position
 232  *                              according to Gadi's email
 233  *                   AJN-1) Minor fix asc == 11 should be asc == 0x11
 234  *                               in idetape_issue_packet_command (did effect
 235  *                               debugging output only)
 236  *                   AJN-2) Added more debugging output, and
 237  *                              added ide-tape: where missing. I would also
 238  *                              like to add tape->name where possible
 239  *                   AJN-3) Added different debug_level's
 240  *                              via /proc/ide/hdc/settings
 241  *                              "debug_level" determines amount of debugging output;
 242  *                              can be changed using /proc/ide/hdx/settings
 243  *                              0 : almost no debugging output
 244  *                              1 : 0+output errors only
 245  *                              2 : 1+output all sensekey/asc
 246  *                              3 : 2+follow all chrdev related procedures
 247  *                              4 : 3+follow all procedures
 248  *                              5 : 4+include pc_stack rq_stack info
 249  *                              6 : 5+USE_COUNT updates
 250  *                   AJN-4) Fixed timeout for retension in idetape_queue_pc_tail
 251  *                              from 5 to 10 minutes
 252  *                   AJN-5) Changed maximum number of blocks to skip when
 253  *                              reading tapes with multiple consecutive write
 254  *                              errors from 100 to 1000 in idetape_get_logical_blk
 255  *                   Proposed changes to code:
 256  *                   1) output "logical_blk_num" via /proc
 257  *                   2) output "current_operation" via /proc
 258  *                   3) Either solve or document the fact that `mt rewind' is
 259  *                      required after reading from /dev/nhtx to be
 260  *                      able to rmmod the idetape module;
 261  *                      Also, sometimes an application finishes but the
 262  *                      device remains `busy' for some time. Same cause ?
 263  *                   Proposed changes to release-notes:
 264  *                   4) write a simple `quickstart' section in the
 265  *                      release notes; I volunteer if you don't want to
 266  *                   5) include a pointer to video4linux in the doc
 267  *                      to stimulate video applications
 268  *                   6) release notes lines 331 and 362: explain what happens
 269  *                      if the application data rate is higher than 1100 KB/s;
 270  *                      similar approach to lower-than-500 kB/s ?
 271  *                   7) 6.6 Comparison; wouldn't it be better to allow different
 272  *                      strategies for read and write ?
 273  *                      Wouldn't it be better to control the tape buffer
 274  *                      contents instead of the bandwidth ?
 275  *                   8) line 536: replace will by would (if I understand
 276  *                      this section correctly, a hypothetical and unwanted situation
 277  *                       is being described)
 278  * Ver 1.16f Dec 15 99   Change place of the secondary OnStream header frames.
 279  * Ver 1.17  Nov 2000 / Jan 2001  Marcel Mol, marcel@mesa.nl
 280  *                      - Add idetape_onstream_mode_sense_tape_parameter_page
 281  *                        function to get tape capacity in frames: tape->capacity.
 282  *                      - Add support for DI-50 drives( or any DI- drive).
 283  *                      - 'workaround' for read error/blank block around block 3000.
 284  *                      - Implement Early warning for end of media for Onstream.
 285  *                      - Cosmetic code changes for readability.
 286  *                      - Idetape_position_tape should not use SKIP bit during
 287  *                        Onstream read recovery.
 288  *                      - Add capacity, logical_blk_num and first/last_frame_position
 289  *                        to /proc/ide/hd?/settings.
 290  *                      - Module use count was gone in the Linux 2.4 driver.
 291  * Ver 1.17a Apr 2001 Willem Riede osst@riede.org
 292  *                      - Get drive's actual block size from mode sense block descriptor
 293  *                      - Limit size of pipeline
 294  * Ver 1.17b Oct 2002   Alan Stern <stern@rowland.harvard.edu>
 295  *                      Changed IDETAPE_MIN_PIPELINE_STAGES to 1 and actually used
 296  *                       it in the code!
 297  *                      Actually removed aborted stages in idetape_abort_pipeline
 298  *                       instead of just changing the command code.
 299  *                      Made the transfer byte count for Request Sense equal to the
 300  *                       actual length of the data transfer.
 301  *                      Changed handling of partial data transfers: they do not
 302  *                       cause DMA errors.
 303  *                      Moved initiation of DMA transfers to the correct place.
 304  *                      Removed reference to unallocated memory.
 305  *                      Made __idetape_discard_read_pipeline return the number of
 306  *                       sectors skipped, not the number of stages.
 307  *                      Replaced errant kfree() calls with __idetape_kfree_stage().
 308  *                      Fixed off-by-one error in testing the pipeline length.
 309  *                      Fixed handling of filemarks in the read pipeline.
 310  *                      Small code optimization for MTBSF and MTBSFM ioctls.
 311  *                      Don't try to unlock the door during device close if is
 312  *                       already unlocked!
 313  *                      Cosmetic fixes to miscellaneous debugging output messages.
 314  *                      Set the minimum /proc/ide/hd?/settings values for "pipeline",
 315  *                       "pipeline_min", and "pipeline_max" to 1.
 316  *
 317  * Here are some words from the first releases of hd.c, which are quoted
 318  * in ide.c and apply here as well:
 319  *
 320  * | Special care is recommended.  Have Fun!
 321  *
 322  */
 323
 324 /*
 325  * An overview of the pipelined operation mode.
 326  *
 327  * In the pipelined write mode, we will usually just add requests to our
 328  * pipeline and return immediately, before we even start to service them. The
 329  * user program will then have enough time to prepare the next request while
 330  * we are still busy servicing previous requests. In the pipelined read mode,
 331  * the situation is similar - we add read-ahead requests into the pipeline,
 332  * before the user even requested them.
 333  *
 334  * The pipeline can be viewed as a "safety net" which will be activated when
 335  * the system load is high and prevents the user backup program from keeping up
 336  * with the current tape speed. At this point, the pipeline will get
 337  * shorter and shorter but the tape will still be streaming at the same speed.
 338  * Assuming we have enough pipeline stages, the system load will hopefully
 339  * decrease before the pipeline is completely empty, and the backup program
 340  * will be able to "catch up" and refill the pipeline again.
 341  *
 342  * When using the pipelined mode, it would be best to disable any type of
 343  * buffering done by the user program, as ide-tape already provides all the
 344  * benefits in the kernel, where it can be done in a more efficient way.
 345  * As we will usually not block the user program on a request, the most
 346  * efficient user code will then be a simple read-write-read-... cycle.
 347  * Any additional logic will usually just slow down the backup process.
 348  *
 349  * Using the pipelined mode, I get a constant over 400 KBps throughput,
 350  * which seems to be the maximum throughput supported by my tape.
 351  *
 352  * However, there are some downfalls:
 353  *
 354  *      1.      We use memory (for data buffers) in proportional to the number
 355  *              of pipeline stages (each stage is about 26 KB with my tape).
 356  *      2.      In the pipelined write mode, we cheat and postpone error codes
 357  *              to the user task. In read mode, the actual tape position
 358  *              will be a bit further than the last requested block.
 359  *
 360  * Concerning (1):
 361  *
 362  *      1.      We allocate stages dynamically only when we need them. When
 363  *              we don't need them, we don't consume additional memory. In
 364  *              case we can't allocate stages, we just manage without them
 365  *              (at the expense of decreased throughput) so when Linux is
 366  *              tight in memory, we will not pose additional difficulties.
 367  *
 368  *      2.      The maximum number of stages (which is, in fact, the maximum
 369  *              amount of memory) which we allocate is limited by the compile
 370  *              time parameter IDETAPE_MAX_PIPELINE_STAGES.
 371  *
 372  *      3.      The maximum number of stages is a controlled parameter - We
 373  *              don't start from the user defined maximum number of stages
 374  *              but from the lower IDETAPE_MIN_PIPELINE_STAGES (again, we
 375  *              will not even allocate this amount of stages if the user
 376  *              program can't handle the speed). We then implement a feedback
 377  *              loop which checks if the pipeline is empty, and if it is, we
 378  *              increase the maximum number of stages as necessary until we
 379  *              reach the optimum value which just manages to keep the tape
 380  *              busy with minimum allocated memory or until we reach
 381  *              IDETAPE_MAX_PIPELINE_STAGES.
 382  *
 383  * Concerning (2):
 384  *
 385  *      In pipelined write mode, ide-tape can not return accurate error codes
 386  *      to the user program since we usually just add the request to the
 387  *      pipeline without waiting for it to be serviced. In case an error
 388  *      occurs, I will report it on the next user request.
 389  *
 390  *      In the pipelined read mode, subsequent read requests or forward
 391  *      filemark spacing will perform correctly, as we preserve all blocks
 392  *      and filemarks which we encountered during our excess read-ahead.
 393  *
 394  *      For accurate tape positioning and error reporting, disabling
 395  *      pipelined mode might be the best option.
 396  *
 397  * You can enable/disable/tune the pipelined operation mode by adjusting
 398  * the compile time parameters below.
 399  */
 400
 401 /*
 402  *      Possible improvements.
 403  *
 404  *      1.      Support for the ATAPI overlap protocol.
 405  *
 406  *              In order to maximize bus throughput, we currently use the DSC
 407  *              overlap method which enables ide.c to service requests from the
 408  *              other device while the tape is busy executing a command. The
 409  *              DSC overlap method involves polling the tape's status register
 410  *              for the DSC bit, and servicing the other device while the tape
 411  *              isn't ready.
 412  *
 413  *              In the current QIC development standard (December 1995),
 414  *              it is recommended that new tape drives will *in addition*
 415  *              implement the ATAPI overlap protocol, which is used for the
 416  *              same purpose - efficient use of the IDE bus, but is interrupt
 417  *              driven and thus has much less CPU overhead.
 418  *
 419  *              ATAPI overlap is likely to be supported in most new ATAPI
 420  *              devices, including new ATAPI cdroms, and thus provides us
 421  *              a method by which we can achieve higher throughput when
 422  *              sharing a (fast) ATA-2 disk with any (slow) new ATAPI device.
 423  */
 424
 425 #define IDETAPE_VERSION "1.19"
 426
 427 #include <linux/module.h>
 428 #include <linux/types.h>
 429 #include <linux/string.h>
 430 #include <linux/kernel.h>
 431 #include <linux/delay.h>
 432 #include <linux/timer.h>
 433 #include <linux/mm.h>
 434 #include <linux/interrupt.h>
 435 #include <linux/jiffies.h>
 436 #include <linux/major.h>
 437 #include <linux/errno.h>
 438 #include <linux/genhd.h>
 439 #include <linux/slab.h>
 440 #include <linux/pci.h>
 441 #include <linux/ide.h>
 442 #include <linux/smp_lock.h>
 443 #include <linux/completion.h>
 444 #include <linux/bitops.h>
 445 #include <linux/mutex.h>
 446
 447 #include <asm/byteorder.h>
 448 #include <asm/irq.h>
 449 #include <asm/uaccess.h>
 450 #include <asm/io.h>
 451 #include <asm/unaligned.h>
 452
 453 /*
 454  * partition
 455  */
 456 typedef struct os_partition_s {
 457         __u8    partition_num;
 458         __u8    par_desc_ver;
 459         __u16   wrt_pass_cntr;
 460         __u32   first_frame_addr;
 461         __u32   last_frame_addr;
 462         __u32   eod_frame_addr;
 463 } os_partition_t;
 464
 465 /*
 466  * DAT entry
 467  */
 468 typedef struct os_dat_entry_s {
 469         __u32   blk_sz;
 470         __u16   blk_cnt;
 471         __u8    flags;
 472         __u8    reserved;
 473 } os_dat_entry_t;
 474
 475 /*
 476  * DAT
 477  */
 478 #define OS_DAT_FLAGS_DATA       (0xc)
 479 #define OS_DAT_FLAGS_MARK       (0x1)
 480
 481 typedef struct os_dat_s {
 482         __u8            dat_sz;
 483         __u8            reserved1;
 484         __u8            entry_cnt;
 485         __u8            reserved3;
 486         os_dat_entry_t  dat_list[16];
 487 } os_dat_t;
 488
 489 #include <linux/mtio.h>
 490
 491 /**************************** Tunable parameters *****************************/
 492
 493
 494 /*
 495  *      Pipelined mode parameters.
 496  *
 497  *      We try to use the minimum number of stages which is enough to
 498  *      keep the tape constantly streaming. To accomplish that, we implement
 499  *      a feedback loop around the maximum number of stages:
 500  *
 501  *      We start from MIN maximum stages (we will not even use MIN stages
 502  *      if we don't need them), increment it by RATE*(MAX-MIN)
 503  *      whenever we sense that the pipeline is empty, until we reach
 504  *      the optimum value or until we reach MAX.
 505  *
 506  *      Setting the following parameter to 0 is illegal: the pipelined mode
 507  *      cannot be disabled (calculate_speeds() divides by tape->max_stages.)
 508  */
 509 #define IDETAPE_MIN_PIPELINE_STAGES       1
 510 #define IDETAPE_MAX_PIPELINE_STAGES     400
 511 #define IDETAPE_INCREASE_STAGES_RATE     20
 512
 513 /*
 514  *      The following are used to debug the driver:
 515  *
 516  *      Setting IDETAPE_DEBUG_INFO to 1 will report device capabilities.
 517  *      Setting IDETAPE_DEBUG_LOG to 1 will log driver flow control.
 518  *      Setting IDETAPE_DEBUG_BUGS to 1 will enable self-sanity checks in
 519  *      some places.
 520  *
 521  *      Setting them to 0 will restore normal operation mode:
 522  *
 523  *              1.      Disable logging normal successful operations.
 524  *              2.      Disable self-sanity checks.
 525  *              3.      Errors will still be logged, of course.
 526  *
 527  *      All the #if DEBUG code will be removed some day, when the driver
 528  *      is verified to be stable enough. This will make it much more
 529  *      esthetic.
 530  */
 531 #define IDETAPE_DEBUG_INFO              0
 532 #define IDETAPE_DEBUG_LOG               0
 533 #define IDETAPE_DEBUG_BUGS              1
 534
 535 /*
 536  *      After each failed packet command we issue a request sense command
 537  *      and retry the packet command IDETAPE_MAX_PC_RETRIES times.
 538  *
 539  *      Setting IDETAPE_MAX_PC_RETRIES to 0 will disable retries.
 540  */
 541 #define IDETAPE_MAX_PC_RETRIES          3
 542
 543 /*
 544  *      With each packet command, we allocate a buffer of
 545  *      IDETAPE_PC_BUFFER_SIZE bytes. This is used for several packet
 546  *      commands (Not for READ/WRITE commands).
 547  */
 548 #define IDETAPE_PC_BUFFER_SIZE          256
 549
 550 /*
 551  *      In various places in the driver, we need to allocate storage
 552  *      for packet commands and requests, which will remain valid while
 553  *      we leave the driver to wait for an interrupt or a timeout event.
 554  */
 555 #define IDETAPE_PC_STACK                (10 + IDETAPE_MAX_PC_RETRIES)
 556
 557 /*
 558  * Some drives (for example, Seagate STT3401A Travan) require a very long
 559  * timeout, because they don't return an interrupt or clear their busy bit
 560  * until after the command completes (even retension commands).
 561  */
 562 #define IDETAPE_WAIT_CMD                (900*HZ)
 563
 564 /*
 565  *      The following parameter is used to select the point in the internal
 566  *      tape fifo in which we will start to refill the buffer. Decreasing
 567  *      the following parameter will improve the system's latency and
 568  *      interactive response, while using a high value might improve system
 569  *      throughput.
 570  */
 571 #define IDETAPE_FIFO_THRESHOLD          2
 572
 573 /*
 574  *      DSC polling parameters.
 575  *
 576  *      Polling for DSC (a single bit in the status register) is a very
 577  *      important function in ide-tape. There are two cases in which we
 578  *      poll for DSC:
 579  *
 580  *      1.      Before a read/write packet command, to ensure that we
 581  *              can transfer data from/to the tape's data buffers, without
 582  *              causing an actual media access. In case the tape is not
 583  *              ready yet, we take out our request from the device
 584  *              request queue, so that ide.c will service requests from
 585  *              the other device on the same interface meanwhile.
 586  *
 587  *      2.      After the successful initialization of a "media access
 588  *              packet command", which is a command which can take a long
 589  *              time to complete (it can be several seconds or even an hour).
 590  *
 591  *              Again, we postpone our request in the middle to free the bus
 592  *              for the other device. The polling frequency here should be
 593  *              lower than the read/write frequency since those media access
 594  *              commands are slow. We start from a "fast" frequency -
 595  *              IDETAPE_DSC_MA_FAST (one second), and if we don't receive DSC
 596  *              after IDETAPE_DSC_MA_THRESHOLD (5 minutes), we switch it to a
 597  *              lower frequency - IDETAPE_DSC_MA_SLOW (1 minute).
 598  *
 599  *      We also set a timeout for the timer, in case something goes wrong.
 600  *      The timeout should be longer then the maximum execution time of a
 601  *      tape operation.
 602  */
 603
 604 /*
 605  *      DSC timings.
 606  */
 607 #define IDETAPE_DSC_RW_MIN              5*HZ/100        /* 50 msec */
 608 #define IDETAPE_DSC_RW_MAX              40*HZ/100       /* 400 msec */
 609 #define IDETAPE_DSC_RW_TIMEOUT          2*60*HZ         /* 2 minutes */
 610 #define IDETAPE_DSC_MA_FAST             2*HZ            /* 2 seconds */
 611 #define IDETAPE_DSC_MA_THRESHOLD        5*60*HZ         /* 5 minutes */
 612 #define IDETAPE_DSC_MA_SLOW             30*HZ           /* 30 seconds */
 613 #define IDETAPE_DSC_MA_TIMEOUT          2*60*60*HZ      /* 2 hours */
 614
 615 /*************************** End of tunable parameters ***********************/
 616
 617 /*
 618  *      Read/Write error simulation
 619  */
 620 #define SIMULATE_ERRORS                 0
 621
 622 /*
 623  *      For general magnetic tape device compatibility.
 624  */
 625 typedef enum {
 626         idetape_direction_none,
 627         idetape_direction_read,
 628         idetape_direction_write
 629 } idetape_chrdev_direction_t;
 630
 631 struct idetape_bh {
 632         u32 b_size;
 633         atomic_t b_count;
 634         struct idetape_bh *b_reqnext;
 635         char *b_data;
 636 };
 637
 638 /*
 639  *      Our view of a packet command.
 640  */
 641 typedef struct idetape_packet_command_s {
 642         u8 c[12];                               /* Actual packet bytes */
 643         int retries;                            /* On each retry, we increment retries */
 644         int error;                              /* Error code */
 645         int request_transfer;                   /* Bytes to transfer */
 646         int actually_transferred;               /* Bytes actually transferred */
 647         int buffer_size;                        /* Size of our data buffer */
 648         struct idetape_bh *bh;
 649         char *b_data;
 650         int b_count;
 651         u8 *buffer;                             /* Data buffer */
 652         u8 *current_position;                   /* Pointer into the above buffer */
 653         ide_startstop_t (*callback) (ide_drive_t *);    /* Called when this packet command is completed */
 654         u8 pc_buffer[IDETAPE_PC_BUFFER_SIZE];   /* Temporary buffer */
 655         unsigned long flags;                    /* Status/Action bit flags: long for set_bit */
 656 } idetape_pc_t;
 657
 658 /*
 659  *      Packet command flag bits.
 660  */
 661 /* Set when an error is considered normal - We won't retry */
 662 #define PC_ABORT                        0
 663 /* 1 When polling for DSC on a media access command */
 664 #define PC_WAIT_FOR_DSC                 1
 665 /* 1 when we prefer to use DMA if possible */
 666 #define PC_DMA_RECOMMENDED              2
 667 /* 1 while DMA in progress */
 668 #define PC_DMA_IN_PROGRESS              3
 669 /* 1 when encountered problem during DMA */
 670 #define PC_DMA_ERROR                    4
 671 /* Data direction */
 672 #define PC_WRITING                      5
 673
 674 /*
 675  *      Capabilities and Mechanical Status Page
 676  */
 677 typedef struct {
 678         unsigned        page_code       :6;     /* Page code - Should be 0x2a */
 679         __u8            reserved0_6     :1;
 680         __u8            ps              :1;     /* parameters saveable */
 681         __u8            page_length;            /* Page Length - Should be 0x12 */
 682         __u8            reserved2, reserved3;
 683         unsigned        ro              :1;     /* Read Only Mode */
 684         unsigned        reserved4_1234  :4;
 685         unsigned        sprev           :1;     /* Supports SPACE in the reverse direction */
 686         unsigned        reserved4_67    :2;
 687         unsigned        reserved5_012   :3;
 688         unsigned        efmt            :1;     /* Supports ERASE command initiated formatting */
 689         unsigned        reserved5_4     :1;
 690         unsigned        qfa             :1;     /* Supports the QFA two partition formats */
 691         unsigned        reserved5_67    :2;
 692         unsigned        lock            :1;     /* Supports locking the volume */
 693         unsigned        locked          :1;     /* The volume is locked */
 694         unsigned        prevent         :1;     /* The device defaults in the prevent state after power up */
 695         unsigned        eject           :1;     /* The device can eject the volume */
 696         __u8            disconnect      :1;     /* The device can break request > ctl */
 697         __u8            reserved6_5     :1;
 698         unsigned        ecc             :1;     /* Supports error correction */
 699         unsigned        cmprs           :1;     /* Supports data compression */
 700         unsigned        reserved7_0     :1;
 701         unsigned        blk512          :1;     /* Supports 512 bytes block size */
 702         unsigned        blk1024         :1;     /* Supports 1024 bytes block size */
 703         unsigned        reserved7_3_6   :4;
 704         unsigned        blk32768        :1;     /* slowb - the device restricts the byte count for PIO */
 705                                                 /* transfers for slow buffer memory ??? */
 706                                                 /* Also 32768 block size in some cases */
 707         __u16           max_speed;              /* Maximum speed supported in KBps */
 708         __u8            reserved10, reserved11;
 709         __u16           ctl;                    /* Continuous Transfer Limit in blocks */
 710         __u16           speed;                  /* Current Speed, in KBps */
 711         __u16           buffer_size;            /* Buffer Size, in 512 bytes */
 712         __u8            reserved18, reserved19;
 713 } idetape_capabilities_page_t;
 714
 715 /*
 716  *      Block Size Page
 717  */
 718 typedef struct {
 719         unsigned        page_code       :6;     /* Page code - Should be 0x30 */
 720         unsigned        reserved1_6     :1;
 721         unsigned        ps              :1;
 722         __u8            page_length;            /* Page Length - Should be 2 */
 723         __u8            reserved2;
 724         unsigned        play32          :1;
 725         unsigned        play32_5        :1;
 726         unsigned        reserved2_23    :2;
 727         unsigned        record32        :1;
 728         unsigned        record32_5      :1;
 729         unsigned        reserved2_6     :1;
 730         unsigned        one             :1;
 731 } idetape_block_size_page_t;
 732
 733 /*
 734  *      A pipeline stage.
 735  */
 736 typedef struct idetape_stage_s {
 737         struct request rq;                      /* The corresponding request */
 738         struct idetape_bh *bh;                  /* The data buffers */
 739         struct idetape_stage_s *next;           /* Pointer to the next stage */
 740 } idetape_stage_t;
 741
 742 /*
 743  *      REQUEST SENSE packet command result - Data Format.
 744  */
 745 typedef struct {
 746         unsigned        error_code      :7;     /* Current of deferred errors */
 747         unsigned        valid           :1;     /* The information field conforms to QIC-157C */
 748         __u8            reserved1       :8;     /* Segment Number - Reserved */
 749         unsigned        sense_key       :4;     /* Sense Key */
 750         unsigned        reserved2_4     :1;     /* Reserved */
 751         unsigned        ili             :1;     /* Incorrect Length Indicator */
 752         unsigned        eom             :1;     /* End Of Medium */
 753         unsigned        filemark        :1;     /* Filemark */
 754         __u32           information __attribute__ ((packed));
 755         __u8            asl;                    /* Additional sense length (n-7) */
 756         __u32           command_specific;       /* Additional command specific information */
 757         __u8            asc;                    /* Additional Sense Code */
 758         __u8            ascq;                   /* Additional Sense Code Qualifier */
 759         __u8            replaceable_unit_code;  /* Field Replaceable Unit Code */
 760         unsigned        sk_specific1    :7;     /* Sense Key Specific */
 761         unsigned        sksv            :1;     /* Sense Key Specific information is valid */
 762         __u8            sk_specific2;           /* Sense Key Specific */
 763         __u8            sk_specific3;           /* Sense Key Specific */
 764         __u8            pad[2];                 /* Padding to 20 bytes */
 765 } idetape_request_sense_result_t;
 766
 767
 768 /*
 769  *      Most of our global data which we need to save even as we leave the
 770  *      driver due to an interrupt or a timer event is stored in a variable
 771  *      of type idetape_tape_t, defined below.
 772  */
 773 typedef struct ide_tape_obj {
 774         ide_drive_t     *drive;
 775         ide_driver_t    *driver;
 776         struct gendisk  *disk;
 777         struct kref     kref;
 778
 779         /*
 780          *      Since a typical character device operation requires more
 781          *      than one packet command, we provide here enough memory
 782          *      for the maximum of interconnected packet commands.
 783          *      The packet commands are stored in the circular array pc_stack.
 784          *      pc_stack_index points to the last used entry, and warps around
 785          *      to the start when we get to the last array entry.
 786          *
 787          *      pc points to the current processed packet command.
 788          *
 789          *      failed_pc points to the last failed packet command, or contains
 790          *      NULL if we do not need to retry any packet command. This is
 791          *      required since an additional packet command is needed before the
 792          *      retry, to get detailed information on what went wrong.
 793          */
 794         /* Current packet command */
 795         idetape_pc_t *pc;
 796         /* Last failed packet command */
 797         idetape_pc_t *failed_pc;
 798         /* Packet command stack */
 799         idetape_pc_t pc_stack[IDETAPE_PC_STACK];
 800         /* Next free packet command storage space */
 801         int pc_stack_index;
 802         struct request rq_stack[IDETAPE_PC_STACK];
 803         /* We implement a circular array */
 804         int rq_stack_index;
 805
 806         /*
 807          *      DSC polling variables.
 808          *
 809          *      While polling for DSC we use postponed_rq to postpone the
 810          *      current request so that ide.c will be able to service
 811          *      pending requests on the other device. Note that at most
 812          *      we will have only one DSC (usually data transfer) request
 813          *      in the device request queue. Additional requests can be
 814          *      queued in our internal pipeline, but they will be visible
 815          *      to ide.c only one at a time.
 816          */
 817         struct request *postponed_rq;
 818         /* The time in which we started polling for DSC */
 819         unsigned long dsc_polling_start;
 820         /* Timer used to poll for dsc */
 821         struct timer_list dsc_timer;
 822         /* Read/Write dsc polling frequency */
 823         unsigned long best_dsc_rw_frequency;
 824         /* The current polling frequency */
 825         unsigned long dsc_polling_frequency;
 826         /* Maximum waiting time */
 827         unsigned long dsc_timeout;
 828
 829         /*
 830          *      Read position information
 831          */
 832         u8 partition;
 833         /* Current block */
 834         unsigned int first_frame_position;
 835         unsigned int last_frame_position;
 836         unsigned int blocks_in_buffer;
 837
 838         /*
 839          *      Last error information
 840          */
 841         u8 sense_key, asc, ascq;
 842
 843         /*
 844          *      Character device operation
 845          */
 846         unsigned int minor;
 847         /* device name */
 848         char name[4];
 849         /* Current character device data transfer direction */
 850         idetape_chrdev_direction_t chrdev_direction;
 851
 852         /*
 853          *      Device information
 854          */
 855         /* Usually 512 or 1024 bytes */
 856         unsigned short tape_block_size;
 857         int user_bs_factor;
 858         /* Copy of the tape's Capabilities and Mechanical Page */
 859         idetape_capabilities_page_t capabilities;
 860
 861         /*
 862          *      Active data transfer request parameters.
 863          *
 864          *      At most, there is only one ide-tape originated data transfer
 865          *      request in the device request queue. This allows ide.c to
 866          *      easily service requests from the other device when we
 867          *      postpone our active request. In the pipelined operation
 868          *      mode, we use our internal pipeline structure to hold
 869          *      more data requests.
 870          *
 871          *      The data buffer size is chosen based on the tape's
 872          *      recommendation.
 873          */
 874         /* Pointer to the request which is waiting in the device request queue */
 875         struct request *active_data_request;
 876         /* Data buffer size (chosen based on the tape's recommendation */
 877         int stage_size;
 878         idetape_stage_t *merge_stage;
 879         int merge_stage_size;
 880         struct idetape_bh *bh;
 881         char *b_data;
 882         int b_count;
 883
 884         /*
 885          *      Pipeline parameters.
 886          *
 887          *      To accomplish non-pipelined mode, we simply set the following
 888          *      variables to zero (or NULL, where appropriate).
 889          */
 890         /* Number of currently used stages */
 891         int nr_stages;
 892         /* Number of pending stages */
 893         int nr_pending_stages;
 894         /* We will not allocate more than this number of stages */
 895         int max_stages, min_pipeline, max_pipeline;
 896         /* The first stage which will be removed from the pipeline */
 897         idetape_stage_t *first_stage;
 898         /* The currently active stage */
 899         idetape_stage_t *active_stage;
 900         /* Will be serviced after the currently active request */
 901         idetape_stage_t *next_stage;
 902         /* New requests will be added to the pipeline here */
 903         idetape_stage_t *last_stage;
 904         /* Optional free stage which we can use */
 905         idetape_stage_t *cache_stage;
 906         int pages_per_stage;
 907         /* Wasted space in each stage */
 908         int excess_bh_size;
 909
 910         /* Status/Action flags: long for set_bit */
 911         unsigned long flags;
 912         /* protects the ide-tape queue */
 913         spinlock_t spinlock;
 914
 915         /*
 916          * Measures average tape speed
 917          */
 918         unsigned long avg_time;
 919         int avg_size;
 920         int avg_speed;
 921
 922         /* last sense information */
 923         idetape_request_sense_result_t sense;
 924
 925         char vendor_id[10];
 926         char product_id[18];
 927         char firmware_revision[6];
 928         int firmware_revision_num;
 929
 930         /* the door is currently locked */
 931         int door_locked;
 932         /* the tape hardware is write protected */
 933         char drv_write_prot;
 934         /* the tape is write protected (hardware or opened as read-only) */
 935         char write_prot;
 936
 937         /*
 938          * Limit the number of times a request can
 939          * be postponed, to avoid an infinite postpone
 940          * deadlock.
 941          */
 942         /* request postpone count limit */
 943         int postpone_cnt;
 944
 945         /*
 946          * Measures number of frames:
 947          *
 948          * 1. written/read to/from the driver pipeline (pipeline_head).
 949          * 2. written/read to/from the tape buffers (idetape_bh).
 950          * 3. written/read by the tape to/from the media (tape_head).
 951          */
 952         int pipeline_head;
 953         int buffer_head;
 954         int tape_head;
 955         int last_tape_head;
 956
 957         /*
 958          * Speed control at the tape buffers input/output
 959          */
 960         unsigned long insert_time;
 961         int insert_size;
 962         int insert_speed;
 963         int max_insert_speed;
 964         int measure_insert_time;
 965
 966         /*
 967          * Measure tape still time, in milliseconds
 968          */
 969         unsigned long tape_still_time_begin;
 970         int tape_still_time;
 971
 972         /*
 973          * Speed regulation negative feedback loop
 974          */
 975         int speed_control;
 976         int pipeline_head_speed;
 977         int controlled_pipeline_head_speed;
 978         int uncontrolled_pipeline_head_speed;
 979         int controlled_last_pipeline_head;
 980         int uncontrolled_last_pipeline_head;
 981         unsigned long uncontrolled_pipeline_head_time;
 982         unsigned long controlled_pipeline_head_time;
 983         int controlled_previous_pipeline_head;
 984         int uncontrolled_previous_pipeline_head;
 985         unsigned long controlled_previous_head_time;
 986         unsigned long uncontrolled_previous_head_time;
 987         int restart_speed_control_req;
 988
 989         /*
 990          * Debug_level determines amount of debugging output;
 991          * can be changed using /proc/ide/hdx/settings
 992          * 0 : almost no debugging output
 993          * 1 : 0+output errors only
 994          * 2 : 1+output all sensekey/asc
 995          * 3 : 2+follow all chrdev related procedures
 996          * 4 : 3+follow all procedures
 997          * 5 : 4+include pc_stack rq_stack info
 998          * 6 : 5+USE_COUNT updates
 999          */
1000          int debug_level;
1001 } idetape_tape_t;
1002
1003 static DEFINE_MUTEX(idetape_ref_mutex);
1004
1005 static struct class *idetape_sysfs_class;
1006
1007 #define to_ide_tape(obj) container_of(obj, struct ide_tape_obj, kref)
1008
1009 #define ide_tape_g(disk) \
1010         container_of((disk)->private_data, struct ide_tape_obj, driver)
1011
1012 static struct ide_tape_obj *ide_tape_get(struct gendisk *disk)
1013 {
1014         struct ide_tape_obj *tape = NULL;
1015
1016         mutex_lock(&idetape_ref_mutex);
1017         tape = ide_tape_g(disk);
1018         if (tape)
1019                 kref_get(&tape->kref);
1020         mutex_unlock(&idetape_ref_mutex);
1021         return tape;
1022 }
1023
1024 static void ide_tape_release(struct kref *);
1025
1026 static void ide_tape_put(struct ide_tape_obj *tape)
1027 {
1028         mutex_lock(&idetape_ref_mutex);
1029         kref_put(&tape->kref, ide_tape_release);
1030         mutex_unlock(&idetape_ref_mutex);
1031 }
1032
1033 /*
1034  *      Tape door status
1035  */
1036 #define DOOR_UNLOCKED                   0
1037 #define DOOR_LOCKED                     1
1038 #define DOOR_EXPLICITLY_LOCKED          2
1039
1040 /*
1041  *      Tape flag bits values.
1042  */
1043 #define IDETAPE_IGNORE_DSC              0
1044 #define IDETAPE_ADDRESS_VALID           1       /* 0 When the tape position is unknown */
1045 #define IDETAPE_BUSY                    2       /* Device already opened */
1046 #define IDETAPE_PIPELINE_ERROR          3       /* Error detected in a pipeline stage */
1047 #define IDETAPE_DETECT_BS               4       /* Attempt to auto-detect the current user block size */
1048 #define IDETAPE_FILEMARK                5       /* Currently on a filemark */
1049 #define IDETAPE_DRQ_INTERRUPT           6       /* DRQ interrupt device */
1050 #define IDETAPE_READ_ERROR              7
1051 #define IDETAPE_PIPELINE_ACTIVE         8       /* pipeline active */
1052 /* 0 = no tape is loaded, so we don't rewind after ejecting */
1053 #define IDETAPE_MEDIUM_PRESENT          9
1054
1055 /*
1056  *      Supported ATAPI tape drives packet commands
1057  */
1058 #define IDETAPE_TEST_UNIT_READY_CMD     0x00
1059 #define IDETAPE_REWIND_CMD              0x01
1060 #define IDETAPE_REQUEST_SENSE_CMD       0x03
1061 #define IDETAPE_READ_CMD                0x08
1062 #define IDETAPE_WRITE_CMD               0x0a
1063 #define IDETAPE_WRITE_FILEMARK_CMD      0x10
1064 #define IDETAPE_SPACE_CMD               0x11
1065 #define IDETAPE_INQUIRY_CMD             0x12
1066 #define IDETAPE_ERASE_CMD               0x19
1067 #define IDETAPE_MODE_SENSE_CMD          0x1a
1068 #define IDETAPE_MODE_SELECT_CMD         0x15
1069 #define IDETAPE_LOAD_UNLOAD_CMD         0x1b
1070 #define IDETAPE_PREVENT_CMD             0x1e
1071 #define IDETAPE_LOCATE_CMD              0x2b
1072 #define IDETAPE_READ_POSITION_CMD       0x34
1073 #define IDETAPE_READ_BUFFER_CMD         0x3c
1074 #define IDETAPE_SET_SPEED_CMD           0xbb
1075
1076 /*
1077  *      Some defines for the READ BUFFER command
1078  */
1079 #define IDETAPE_RETRIEVE_FAULTY_BLOCK   6
1080
1081 /*
1082  *      Some defines for the SPACE command
1083  */
1084 #define IDETAPE_SPACE_OVER_FILEMARK     1
1085 #define IDETAPE_SPACE_TO_EOD            3
1086
1087 /*
1088  *      Some defines for the LOAD UNLOAD command
1089  */
1090 #define IDETAPE_LU_LOAD_MASK            1
1091 #define IDETAPE_LU_RETENSION_MASK       2
1092 #define IDETAPE_LU_EOT_MASK             4
1093
1094 /*
1095  *      Special requests for our block device strategy routine.
1096  *
1097  *      In order to service a character device command, we add special
1098  *      requests to the tail of our block device request queue and wait
1099  *      for their completion.
1100  */
1101
1102 enum {
1103         REQ_IDETAPE_PC1         = (1 << 0), /* packet command (first stage) */
1104         REQ_IDETAPE_PC2         = (1 << 1), /* packet command (second stage) */
1105         REQ_IDETAPE_READ        = (1 << 2),
1106         REQ_IDETAPE_WRITE       = (1 << 3),
1107         REQ_IDETAPE_READ_BUFFER = (1 << 4),
1108 };
1109
1110 /*
1111  *      Error codes which are returned in rq->errors to the higher part
1112  *      of the driver.
1113  */
1114 #define IDETAPE_ERROR_GENERAL           101
1115 #define IDETAPE_ERROR_FILEMARK          102
1116 #define IDETAPE_ERROR_EOD               103
1117
1118 /*
1119  *      The following is used to format the general configuration word of
1120  *      the ATAPI IDENTIFY DEVICE command.
1121  */
1122 struct idetape_id_gcw {
1123         unsigned packet_size            :2;     /* Packet Size */
1124         unsigned reserved234            :3;     /* Reserved */
1125         unsigned drq_type               :2;     /* Command packet DRQ type */
1126         unsigned removable              :1;     /* Removable media */
1127         unsigned device_type            :5;     /* Device type */
1128         unsigned reserved13             :1;     /* Reserved */
1129         unsigned protocol               :2;     /* Protocol type */
1130 };
1131
1132 /*
1133  *      INQUIRY packet command - Data Format (From Table 6-8 of QIC-157C)
1134  */
1135 typedef struct {
1136         unsigned        device_type     :5;     /* Peripheral Device Type */
1137         unsigned        reserved0_765   :3;     /* Peripheral Qualifier - Reserved */
1138         unsigned        reserved1_6t0   :7;     /* Reserved */
1139         unsigned        rmb             :1;     /* Removable Medium Bit */
1140         unsigned        ansi_version    :3;     /* ANSI Version */
1141         unsigned        ecma_version    :3;     /* ECMA Version */
1142         unsigned        iso_version     :2;     /* ISO Version */
1143         unsigned        response_format :4;     /* Response Data Format */
1144         unsigned        reserved3_45    :2;     /* Reserved */
1145         unsigned        reserved3_6     :1;     /* TrmIOP - Reserved */
1146         unsigned        reserved3_7     :1;     /* AENC - Reserved */
1147         __u8            additional_length;      /* Additional Length (total_length-4) */
1148         __u8            rsv5, rsv6, rsv7;       /* Reserved */
1149         __u8            vendor_id[8];           /* Vendor Identification */
1150         __u8            product_id[16];         /* Product Identification */
1151         __u8            revision_level[4];      /* Revision Level */
1152         __u8            vendor_specific[20];    /* Vendor Specific - Optional */
1153         __u8            reserved56t95[40];      /* Reserved - Optional */
1154                                                 /* Additional information may be returned */
1155 } idetape_inquiry_result_t;
1156
1157 /*
1158  *      READ POSITION packet command - Data Format (From Table 6-57)
1159  */
1160 typedef struct {
1161         unsigned        reserved0_10    :2;     /* Reserved */
1162         unsigned        bpu             :1;     /* Block Position Unknown */
1163         unsigned        reserved0_543   :3;     /* Reserved */
1164         unsigned        eop             :1;     /* End Of Partition */
1165         unsigned        bop             :1;     /* Beginning Of Partition */
1166         u8              partition;              /* Partition Number */
1167         u8              reserved2, reserved3;   /* Reserved */
1168         u32             first_block;            /* First Block Location */
1169         u32             last_block;             /* Last Block Location (Optional) */
1170         u8              reserved12;             /* Reserved */
1171         u8              blocks_in_buffer[3];    /* Blocks In Buffer - (Optional) */
1172         u32             bytes_in_buffer;        /* Bytes In Buffer (Optional) */
1173 } idetape_read_position_result_t;
1174
1175 /*
1176  *      Follows structures which are related to the SELECT SENSE / MODE SENSE
1177  *      packet commands. Those packet commands are still not supported
1178  *      by ide-tape.
1179  */
1180 #define IDETAPE_BLOCK_DESCRIPTOR        0
1181 #define IDETAPE_CAPABILITIES_PAGE       0x2a
1182 #define IDETAPE_PARAMTR_PAGE            0x2b   /* Onstream DI-x0 only */
1183 #define IDETAPE_BLOCK_SIZE_PAGE         0x30
1184 #define IDETAPE_BUFFER_FILLING_PAGE     0x33
1185
1186 /*
1187  *      Mode Parameter Header for the MODE SENSE packet command
1188  */
1189 typedef struct {
1190         __u8    mode_data_length;       /* Length of the following data transfer */
1191         __u8    medium_type;            /* Medium Type */
1192         __u8    dsp;                    /* Device Specific Parameter */
1193         __u8    bdl;                    /* Block Descriptor Length */
1194 #if 0
1195         /* data transfer page */
1196         __u8    page_code       :6;
1197         __u8    reserved0_6     :1;
1198         __u8    ps              :1;     /* parameters saveable */
1199         __u8    page_length;            /* page Length == 0x02 */
1200         __u8    reserved2;
1201         __u8    read32k         :1;     /* 32k blk size (data only) */
1202         __u8    read32k5        :1;     /* 32.5k blk size (data&AUX) */
1203         __u8    reserved3_23    :2;
1204         __u8    write32k        :1;     /* 32k blk size (data only) */
1205         __u8    write32k5       :1;     /* 32.5k blk size (data&AUX) */
1206         __u8    reserved3_6     :1;
1207         __u8    streaming       :1;     /* streaming mode enable */
1208 #endif
1209 } idetape_mode_parameter_header_t;
1210
1211 /*
1212  *      Mode Parameter Block Descriptor the MODE SENSE packet command
1213  *
1214  *      Support for block descriptors is optional.
1215  */
1216 typedef struct {
1217         __u8            density_code;           /* Medium density code */
1218         __u8            blocks[3];              /* Number of blocks */
1219         __u8            reserved4;              /* Reserved */
1220         __u8            length[3];              /* Block Length */
1221 } idetape_parameter_block_descriptor_t;
1222
1223 /*
1224  *      The Data Compression Page, as returned by the MODE SENSE packet command.
1225  */
1226 typedef struct {
1227         unsigned        page_code       :6;     /* Page Code - Should be 0xf */
1228         unsigned        reserved0       :1;     /* Reserved */
1229         unsigned        ps              :1;
1230         __u8            page_length;            /* Page Length - Should be 14 */
1231         unsigned        reserved2       :6;     /* Reserved */
1232         unsigned        dcc             :1;     /* Data Compression Capable */
1233         unsigned        dce             :1;     /* Data Compression Enable */
1234         unsigned        reserved3       :5;     /* Reserved */
1235         unsigned        red             :2;     /* Report Exception on Decompression */
1236         unsigned        dde             :1;     /* Data Decompression Enable */
1237         __u32           ca;                     /* Compression Algorithm */
1238         __u32           da;                     /* Decompression Algorithm */
1239         __u8            reserved[4];            /* Reserved */
1240 } idetape_data_compression_page_t;
1241
1242 /*
1243  *      The Medium Partition Page, as returned by the MODE SENSE packet command.
1244  */
1245 typedef struct {
1246         unsigned        page_code       :6;     /* Page Code - Should be 0x11 */
1247         unsigned        reserved1_6     :1;     /* Reserved */
1248         unsigned        ps              :1;
1249         __u8            page_length;            /* Page Length - Should be 6 */
1250         __u8            map;                    /* Maximum Additional Partitions - Should be 0 */
1251         __u8            apd;                    /* Additional Partitions Defined - Should be 0 */
1252         unsigned        reserved4_012   :3;     /* Reserved */
1253         unsigned        psum            :2;     /* Should be 0 */
1254         unsigned        idp             :1;     /* Should be 0 */
1255         unsigned        sdp             :1;     /* Should be 0 */
1256         unsigned        fdp             :1;     /* Fixed Data Partitions */
1257         __u8            mfr;                    /* Medium Format Recognition */
1258         __u8            reserved[2];            /* Reserved */
1259 } idetape_medium_partition_page_t;
1260
1261 /*
1262  *      Run time configurable parameters.
1263  */
1264 typedef struct {
1265         int     dsc_rw_frequency;
1266         int     dsc_media_access_frequency;
1267         int     nr_stages;
1268 } idetape_config_t;
1269
1270 /*
1271  *      The variables below are used for the character device interface.
1272  *      Additional state variables are defined in our ide_drive_t structure.
1273  */
1274 static struct ide_tape_obj * idetape_devs[MAX_HWIFS * MAX_DRIVES];
1275
1276 #define ide_tape_f(file) ((file)->private_data)
1277
1278 static struct ide_tape_obj *ide_tape_chrdev_get(unsigned int i)
1279 {
1280         struct ide_tape_obj *tape = NULL;
1281
1282         mutex_lock(&idetape_ref_mutex);
1283         tape = idetape_devs[i];
1284         if (tape)
1285                 kref_get(&tape->kref);
1286         mutex_unlock(&idetape_ref_mutex);
1287         return tape;
1288 }
1289
1290 /*
1291  *      Function declarations
1292  *
1293  */
1294 static int idetape_chrdev_release (struct inode *inode, struct file *filp);
1295 static void idetape_write_release (ide_drive_t *drive, unsigned int minor);
1296
1297 /*
1298  * Too bad. The drive wants to send us data which we are not ready to accept.
1299  * Just throw it away.
1300  */
1301 static void idetape_discard_data (ide_drive_t *drive, unsigned int bcount)
1302 {
1303         while (bcount--)
1304                 (void) HWIF(drive)->INB(IDE_DATA_REG);
1305 }
1306
1307 static void idetape_input_buffers (ide_drive_t *drive, idetape_pc_t *pc, unsigned int bcount)
1308 {
1309         struct idetape_bh *bh = pc->bh;
1310         int count;
1311
1312         while (bcount) {
1313 #if IDETAPE_DEBUG_BUGS
1314                 if (bh == NULL) {
1315                         printk(KERN_ERR "ide-tape: bh == NULL in "
1316                                 "idetape_input_buffers\n");
1317                         idetape_discard_data(drive, bcount);
1318                         return;
1319                 }
1320 #endif /* IDETAPE_DEBUG_BUGS */
1321                 count = min((unsigned int)(bh->b_size - atomic_read(&bh->b_count)), bcount);
1322                 HWIF(drive)->atapi_input_bytes(drive, bh->b_data + atomic_read(&bh->b_count), count);
1323                 bcount -= count;
1324                 atomic_add(count, &bh->b_count);
1325                 if (atomic_read(&bh->b_count) == bh->b_size) {
1326                         bh = bh->b_reqnext;
1327                         if (bh)
1328                                 atomic_set(&bh->b_count, 0);
1329                 }
1330         }
1331         pc->bh = bh;
1332 }
1333
1334 static void idetape_output_buffers (ide_drive_t *drive, idetape_pc_t *pc, unsigned int bcount)
1335 {
1336         struct idetape_bh *bh = pc->bh;
1337         int count;
1338
1339         while (bcount) {
1340 #if IDETAPE_DEBUG_BUGS
1341                 if (bh == NULL) {
1342                         printk(KERN_ERR "ide-tape: bh == NULL in "
1343                                 "idetape_output_buffers\n");
1344                         return;
1345                 }
1346 #endif /* IDETAPE_DEBUG_BUGS */
1347                 count = min((unsigned int)pc->b_count, (unsigned int)bcount);
1348                 HWIF(drive)->atapi_output_bytes(drive, pc->b_data, count);
1349                 bcount -= count;
1350                 pc->b_data += count;
1351                 pc->b_count -= count;
1352                 if (!pc->b_count) {
1353                         pc->bh = bh = bh->b_reqnext;
1354                         if (bh) {
1355                                 pc->b_data = bh->b_data;
1356                                 pc->b_count = atomic_read(&bh->b_count);
1357                         }
1358                 }
1359         }
1360 }
1361
1362 static void idetape_update_buffers (idetape_pc_t *pc)
1363 {
1364         struct idetape_bh *bh = pc->bh;
1365         int count;
1366         unsigned int bcount = pc->actually_transferred;
1367
1368         if (test_bit(PC_WRITING, &pc->flags))
1369                 return;
1370         while (bcount) {
1371 #if IDETAPE_DEBUG_BUGS
1372                 if (bh == NULL) {
1373                         printk(KERN_ERR "ide-tape: bh == NULL in "
1374                                 "idetape_update_buffers\n");
1375                         return;
1376                 }
1377 #endif /* IDETAPE_DEBUG_BUGS */
1378                 count = min((unsigned int)bh->b_size, (unsigned int)bcount);
1379                 atomic_set(&bh->b_count, count);
1380                 if (atomic_read(&bh->b_count) == bh->b_size)
1381                         bh = bh->b_reqnext;
1382                 bcount -= count;
1383         }
1384         pc->bh = bh;
1385 }
1386
1387 /*
1388  *      idetape_next_pc_storage returns a pointer to a place in which we can
1389  *      safely store a packet command, even though we intend to leave the
1390  *      driver. A storage space for a maximum of IDETAPE_PC_STACK packet
1391  *      commands is allocated at initialization time.
1392  */
1393 static idetape_pc_t *idetape_next_pc_storage (ide_drive_t *drive)
1394 {
1395         idetape_tape_t *tape = drive->driver_data;
1396
1397 #if IDETAPE_DEBUG_LOG
1398         if (tape->debug_level >= 5)
1399                 printk(KERN_INFO "ide-tape: pc_stack_index=%d\n",
1400                         tape->pc_stack_index);
1401 #endif /* IDETAPE_DEBUG_LOG */
1402         if (tape->pc_stack_index == IDETAPE_PC_STACK)
1403                 tape->pc_stack_index=0;
1404         return (&tape->pc_stack[tape->pc_stack_index++]);
1405 }
1406
1407 /*
1408  *      idetape_next_rq_storage is used along with idetape_next_pc_storage.
1409  *      Since we queue packet commands in the request queue, we need to
1410  *      allocate a request, along with the allocation of a packet command.
1411  */
1412
1413 /**************************************************************
1414  *                                                            *
1415  *  This should get fixed to use kmalloc(.., GFP_ATOMIC)      *
1416  *  followed later on by kfree().   -ml                       *
1417  *                                                            *
1418  **************************************************************/
1419
1420 static struct request *idetape_next_rq_storage (ide_drive_t *drive)
1421 {
1422         idetape_tape_t *tape = drive->driver_data;
1423
1424 #if IDETAPE_DEBUG_LOG
1425         if (tape->debug_level >= 5)
1426                 printk(KERN_INFO "ide-tape: rq_stack_index=%d\n",
1427                         tape->rq_stack_index);
1428 #endif /* IDETAPE_DEBUG_LOG */
1429         if (tape->rq_stack_index == IDETAPE_PC_STACK)
1430                 tape->rq_stack_index=0;
1431         return (&tape->rq_stack[tape->rq_stack_index++]);
1432 }
1433
1434 /*
1435  *      idetape_init_pc initializes a packet command.
1436  */
1437 static void idetape_init_pc (idetape_pc_t *pc)
1438 {
1439         memset(pc->c, 0, 12);
1440         pc->retries = 0;
1441         pc->flags = 0;
1442         pc->request_transfer = 0;
1443         pc->buffer = pc->pc_buffer;
1444         pc->buffer_size = IDETAPE_PC_BUFFER_SIZE;
1445         pc->bh = NULL;
1446         pc->b_data = NULL;
1447 }
1448
1449 /*
1450  *      idetape_analyze_error is called on each failed packet command retry
1451  *      to analyze the request sense. We currently do not utilize this
1452  *      information.
1453  */
1454 static void idetape_analyze_error (ide_drive_t *drive, idetape_request_sense_result_t *result)
1455 {
1456         idetape_tape_t *tape = drive->driver_data;
1457         idetape_pc_t *pc = tape->failed_pc;
1458
1459         tape->sense     = *result;
1460         tape->sense_key = result->sense_key;
1461         tape->asc       = result->asc;
1462         tape->ascq      = result->ascq;
1463 #if IDETAPE_DEBUG_LOG
1464         /*
1465          *      Without debugging, we only log an error if we decided to
1466          *      give up retrying.
1467          */
1468         if (tape->debug_level >= 1)
1469                 printk(KERN_INFO "ide-tape: pc = %x, sense key = %x, "
1470                         "asc = %x, ascq = %x\n",
1471                         pc->c[0], result->sense_key,
1472                         result->asc, result->ascq);
1473 #endif /* IDETAPE_DEBUG_LOG */
1474
1475         /*
1476          *      Correct pc->actually_transferred by asking the tape.
1477          */
1478         if (test_bit(PC_DMA_ERROR, &pc->flags)) {
1479                 pc->actually_transferred = pc->request_transfer - tape->tape_block_size * ntohl(get_unaligned(&result->information));
1480                 idetape_update_buffers(pc);
1481         }
1482
1483         /*
1484          * If error was the result of a zero-length read or write command,
1485          * with sense key=5, asc=0x22, ascq=0, let it slide.  Some drives
1486          * (i.e. Seagate STT3401A Travan) don't support 0-length read/writes.
1487          */
1488         if ((pc->c[0] == IDETAPE_READ_CMD || pc->c[0] == IDETAPE_WRITE_CMD)
1489             && pc->c[4] == 0 && pc->c[3] == 0 && pc->c[2] == 0) { /* length==0 */
1490                 if (result->sense_key == 5) {
1491                         /* don't report an error, everything's ok */
1492                         pc->error = 0;
1493                         /* don't retry read/write */
1494                         set_bit(PC_ABORT, &pc->flags);
1495                 }
1496         }
1497         if (pc->c[0] == IDETAPE_READ_CMD && result->filemark) {
1498                 pc->error = IDETAPE_ERROR_FILEMARK;
1499                 set_bit(PC_ABORT, &pc->flags);
1500         }
1501         if (pc->c[0] == IDETAPE_WRITE_CMD) {
1502                 if (result->eom ||
1503                     (result->sense_key == 0xd && result->asc == 0x0 &&
1504                      result->ascq == 0x2)) {
1505                         pc->error = IDETAPE_ERROR_EOD;
1506                         set_bit(PC_ABORT, &pc->flags);
1507                 }
1508         }
1509         if (pc->c[0] == IDETAPE_READ_CMD || pc->c[0] == IDETAPE_WRITE_CMD) {
1510                 if (result->sense_key == 8) {
1511                         pc->error = IDETAPE_ERROR_EOD;
1512                         set_bit(PC_ABORT, &pc->flags);
1513                 }
1514                 if (!test_bit(PC_ABORT, &pc->flags) &&
1515                     pc->actually_transferred)
1516                         pc->retries = IDETAPE_MAX_PC_RETRIES + 1;
1517         }
1518 }
1519
1520 /*
1521  * idetape_active_next_stage will declare the next stage as "active".
1522  */
1523 static void idetape_active_next_stage (ide_drive_t *drive)
1524 {
1525         idetape_tape_t *tape = drive->driver_data;
1526         idetape_stage_t *stage = tape->next_stage;
1527         struct request *rq = &stage->rq;
1528
1529 #if IDETAPE_DEBUG_LOG
1530         if (tape->debug_level >= 4)
1531                 printk(KERN_INFO "ide-tape: Reached idetape_active_next_stage\n");
1532 #endif /* IDETAPE_DEBUG_LOG */
1533 #if IDETAPE_DEBUG_BUGS
1534         if (stage == NULL) {
1535                 printk(KERN_ERR "ide-tape: bug: Trying to activate a non existing stage\n");
1536                 return;
1537         }
1538 #endif /* IDETAPE_DEBUG_BUGS */
1539
1540         rq->rq_disk = tape->disk;
1541         rq->buffer = NULL;
1542         rq->special = (void *)stage->bh;
1543         tape->active_data_request = rq;
1544         tape->active_stage = stage;
1545         tape->next_stage = stage->next;
1546 }
1547
1548 /*
1549  *      idetape_increase_max_pipeline_stages is a part of the feedback
1550  *      loop which tries to find the optimum number of stages. In the
1551  *      feedback loop, we are starting from a minimum maximum number of
1552  *      stages, and if we sense that the pipeline is empty, we try to
1553  *      increase it, until we reach the user compile time memory limit.
1554  */
1555 static void idetape_increase_max_pipeline_stages (ide_drive_t *drive)
1556 {
1557         idetape_tape_t *tape = drive->driver_data;
1558         int increase = (tape->max_pipeline - tape->min_pipeline) / 10;
1559
1560 #if IDETAPE_DEBUG_LOG
1561         if (tape->debug_level >= 4)
1562                 printk (KERN_INFO "ide-tape: Reached idetape_increase_max_pipeline_stages\n");
1563 #endif /* IDETAPE_DEBUG_LOG */
1564
1565         tape->max_stages += max(increase, 1);
1566         tape->max_stages = max(tape->max_stages, tape->min_pipeline);
1567         tape->max_stages = min(tape->max_stages, tape->max_pipeline);
1568 }
1569
1570 /*
1571  *      idetape_kfree_stage calls kfree to completely free a stage, along with
1572  *      its related buffers.
1573  */
1574 static void __idetape_kfree_stage (idetape_stage_t *stage)
1575 {
1576         struct idetape_bh *prev_bh, *bh = stage->bh;
1577         int size;
1578
1579         while (bh != NULL) {
1580                 if (bh->b_data != NULL) {
1581                         size = (int) bh->b_size;
1582                         while (size > 0) {
1583                                 free_page((unsigned long) bh->b_data);
1584                                 size -= PAGE_SIZE;
1585                                 bh->b_data += PAGE_SIZE;
1586                         }
1587                 }
1588                 prev_bh = bh;
1589                 bh = bh->b_reqnext;
1590                 kfree(prev_bh);
1591         }
1592         kfree(stage);
1593 }
1594
1595 static void idetape_kfree_stage (idetape_tape_t *tape, idetape_stage_t *stage)
1596 {
1597         __idetape_kfree_stage(stage);
1598 }
1599
1600 /*
1601  *      idetape_remove_stage_head removes tape->first_stage from the pipeline.
1602  *      The caller should avoid race conditions.
1603  */
1604 static void idetape_remove_stage_head (ide_drive_t *drive)
1605 {
1606         idetape_tape_t *tape = drive->driver_data;
1607         idetape_stage_t *stage;
1608
1609 #if IDETAPE_DEBUG_LOG
1610         if (tape->debug_level >= 4)
1611                 printk(KERN_INFO "ide-tape: Reached idetape_remove_stage_head\n");
1612 #endif /* IDETAPE_DEBUG_LOG */
1613 #if IDETAPE_DEBUG_BUGS
1614         if (tape->first_stage == NULL) {
1615                 printk(KERN_ERR "ide-tape: bug: tape->first_stage is NULL\n");
1616                 return;
1617         }
1618         if (tape->active_stage == tape->first_stage) {
1619                 printk(KERN_ERR "ide-tape: bug: Trying to free our active pipeline stage\n");
1620                 return;
1621         }
1622 #endif /* IDETAPE_DEBUG_BUGS */
1623         stage = tape->first_stage;
1624         tape->first_stage = stage->next;
1625         idetape_kfree_stage(tape, stage);
1626         tape->nr_stages--;
1627         if (tape->first_stage == NULL) {
1628                 tape->last_stage = NULL;
1629 #if IDETAPE_DEBUG_BUGS
1630                 if (tape->next_stage != NULL)
1631                         printk(KERN_ERR "ide-tape: bug: tape->next_stage != NULL\n");
1632                 if (tape->nr_stages)
1633                         printk(KERN_ERR "ide-tape: bug: nr_stages should be 0 now\n");
1634 #endif /* IDETAPE_DEBUG_BUGS */
1635         }
1636 }
1637
1638 /*
1639  * This will free all the pipeline stages starting from new_last_stage->next
1640  * to the end of the list, and point tape->last_stage to new_last_stage.
1641  */
1642 static void idetape_abort_pipeline(ide_drive_t *drive,
1643                                    idetape_stage_t *new_last_stage)
1644 {
1645         idetape_tape_t *tape = drive->driver_data;
1646         idetape_stage_t *stage = new_last_stage->next;
1647         idetape_stage_t *nstage;
1648
1649 #if IDETAPE_DEBUG_LOG
1650         if (tape->debug_level >= 4)
1651                 printk(KERN_INFO "ide-tape: %s: idetape_abort_pipeline called\n", tape->name);
1652 #endif
1653         while (stage) {
1654                 nstage = stage->next;
1655                 idetape_kfree_stage(tape, stage);
1656                 --tape->nr_stages;
1657                 --tape->nr_pending_stages;
1658                 stage = nstage;
1659         }
1660         if (new_last_stage)
1661                 new_last_stage->next = NULL;
1662         tape->last_stage = new_last_stage;
1663         tape->next_stage = NULL;
1664 }
1665
1666 /*
1667  *      idetape_end_request is used to finish servicing a request, and to
1668  *      insert a pending pipeline request into the main device queue.
1669  */
1670 static int idetape_end_request(ide_drive_t *drive, int uptodate, int nr_sects)
1671 {
1672         struct request *rq = HWGROUP(drive)->rq;
1673         idetape_tape_t *tape = drive->driver_data;
1674         unsigned long flags;
1675         int error;
1676         int remove_stage = 0;
1677         idetape_stage_t *active_stage;
1678
1679 #if IDETAPE_DEBUG_LOG
1680         if (tape->debug_level >= 4)
1681         printk(KERN_INFO "ide-tape: Reached idetape_end_request\n");
1682 #endif /* IDETAPE_DEBUG_LOG */
1683
1684         switch (uptodate) {
1685                 case 0: error = IDETAPE_ERROR_GENERAL; break;
1686                 case 1: error = 0; break;
1687                 default: error = uptodate;
1688         }
1689         rq->errors = error;
1690         if (error)
1691                 tape->failed_pc = NULL;
1692
1693         if (!blk_special_request(rq)) {
1694                 ide_end_request(drive, uptodate, nr_sects);
1695                 return 0;
1696         }
1697
1698         spin_lock_irqsave(&tape->spinlock, flags);
1699
1700         /* The request was a pipelined data transfer request */
1701         if (tape->active_data_request == rq) {
1702                 active_stage = tape->active_stage;
1703                 tape->active_stage = NULL;
1704                 tape->active_data_request = NULL;
1705                 tape->nr_pending_stages--;
1706                 if (rq->cmd[0] & REQ_IDETAPE_WRITE) {
1707                         remove_stage = 1;
1708                         if (error) {
1709                                 set_bit(IDETAPE_PIPELINE_ERROR, &tape->flags);
1710                                 if (error == IDETAPE_ERROR_EOD)
1711                                         idetape_abort_pipeline(drive, active_stage);
1712                         }
1713                 } else if (rq->cmd[0] & REQ_IDETAPE_READ) {
1714                         if (error == IDETAPE_ERROR_EOD) {
1715                                 set_bit(IDETAPE_PIPELINE_ERROR, &tape->flags);
1716                                 idetape_abort_pipeline(drive, active_stage);
1717                         }
1718                 }
1719                 if (tape->next_stage != NULL) {
1720                         idetape_active_next_stage(drive);
1721
1722                         /*
1723                          * Insert the next request into the request queue.
1724                          */
1725                         (void) ide_do_drive_cmd(drive, tape->active_data_request, ide_end);
1726                 } else if (!error) {
1727                                 idetape_increase_max_pipeline_stages(drive);
1728                 }
1729         }
1730         ide_end_drive_cmd(drive, 0, 0);
1731 //      blkdev_dequeue_request(rq);
1732 //      drive->rq = NULL;
1733 //      end_that_request_last(rq);
1734
1735         if (remove_stage)
1736                 idetape_remove_stage_head(drive);
1737         if (tape->active_data_request == NULL)
1738                 clear_bit(IDETAPE_PIPELINE_ACTIVE, &tape->flags);
1739         spin_unlock_irqrestore(&tape->spinlock, flags);
1740         return 0;
1741 }
1742
1743 static ide_startstop_t idetape_request_sense_callback (ide_drive_t *drive)
1744 {
1745         idetape_tape_t *tape = drive->driver_data;
1746
1747 #if IDETAPE_DEBUG_LOG
1748         if (tape->debug_level >= 4)
1749                 printk(KERN_INFO "ide-tape: Reached idetape_request_sense_callback\n");
1750 #endif /* IDETAPE_DEBUG_LOG */
1751         if (!tape->pc->error) {
1752                 idetape_analyze_error(drive, (idetape_request_sense_result_t *) tape->pc->buffer);
1753                 idetape_end_request(drive, 1, 0);
1754         } else {
1755                 printk(KERN_ERR "ide-tape: Error in REQUEST SENSE itself - Aborting request!\n");
1756                 idetape_end_request(drive, 0, 0);
1757         }
1758         return ide_stopped;
1759 }
1760
1761 static void idetape_create_request_sense_cmd (idetape_pc_t *pc)
1762 {
1763         idetape_init_pc(pc);
1764         pc->c[0] = IDETAPE_REQUEST_SENSE_CMD;
1765         pc->c[4] = 20;
1766         pc->request_transfer = 20;
1767         pc->callback = &idetape_request_sense_callback;
1768 }
1769
1770 static void idetape_init_rq(struct request *rq, u8 cmd)
1771 {
1772         memset(rq, 0, sizeof(*rq));
1773         rq->cmd_type = REQ_TYPE_SPECIAL;
1774         rq->cmd[0] = cmd;
1775 }
1776
1777 /*
1778  *      idetape_queue_pc_head generates a new packet command request in front
1779  *      of the request queue, before the current request, so that it will be
1780  *      processed immediately, on the next pass through the driver.
1781  *
1782  *      idetape_queue_pc_head is called from the request handling part of
1783  *      the driver (the "bottom" part). Safe storage for the request should
1784  *      be allocated with idetape_next_pc_storage and idetape_next_rq_storage
1785  *      before calling idetape_queue_pc_head.
1786  *
1787  *      Memory for those requests is pre-allocated at initialization time, and
1788  *      is limited to IDETAPE_PC_STACK requests. We assume that we have enough
1789  *      space for the maximum possible number of inter-dependent packet commands.
1790  *
1791  *      The higher level of the driver - The ioctl handler and the character
1792  *      device handling functions should queue request to the lower level part
1793  *      and wait for their completion using idetape_queue_pc_tail or
1794  *      idetape_queue_rw_tail.
1795  */
1796 static void idetape_queue_pc_head (ide_drive_t *drive, idetape_pc_t *pc,struct request *rq)
1797 {
1798         struct ide_tape_obj *tape = drive->driver_data;
1799
1800         idetape_init_rq(rq, REQ_IDETAPE_PC1);
1801         rq->buffer = (char *) pc;
1802         rq->rq_disk = tape->disk;
1803         (void) ide_do_drive_cmd(drive, rq, ide_preempt);
1804 }
1805
1806 /*
1807  *      idetape_retry_pc is called when an error was detected during the
1808  *      last packet command. We queue a request sense packet command in
1809  *      the head of the request list.
1810  */
1811 static ide_startstop_t idetape_retry_pc (ide_drive_t *drive)
1812 {
1813         idetape_tape_t *tape = drive->driver_data;
1814         idetape_pc_t *pc;
1815         struct request *rq;
1816
1817         (void)drive->hwif->INB(IDE_ERROR_REG);
1818         pc = idetape_next_pc_storage(drive);
1819         rq = idetape_next_rq_storage(drive);
1820         idetape_create_request_sense_cmd(pc);
1821         set_bit(IDETAPE_IGNORE_DSC, &tape->flags);
1822         idetape_queue_pc_head(drive, pc, rq);
1823         return ide_stopped;
1824 }
1825
1826 /*
1827  *      idetape_postpone_request postpones the current request so that
1828  *      ide.c will be able to service requests from another device on
1829  *      the same hwgroup while we are polling for DSC.
1830  */
1831 static void idetape_postpone_request (ide_drive_t *drive)
1832 {
1833         idetape_tape_t *tape = drive->driver_data;
1834
1835 #if IDETAPE_DEBUG_LOG
1836         if (tape->debug_level >= 4)
1837                 printk(KERN_INFO "ide-tape: idetape_postpone_request\n");
1838 #endif
1839         tape->postponed_rq = HWGROUP(drive)->rq;
1840         ide_stall_queue(drive, tape->dsc_polling_frequency);
1841 }
1842
1843 /*
1844  *      idetape_pc_intr is the usual interrupt handler which will be called
1845  *      during a packet command. We will transfer some of the data (as
1846  *      requested by the drive) and will re-point interrupt handler to us.
1847  *      When data transfer is finished, we will act according to the
1848  *      algorithm described before idetape_issue_packet_command.
1849  *
1850  */
1851 static ide_startstop_t idetape_pc_intr (ide_drive_t *drive)
1852 {
1853         ide_hwif_t *hwif = drive->hwif;
1854         idetape_tape_t *tape = drive->driver_data;
1855         idetape_pc_t *pc = tape->pc;
1856         unsigned int temp;
1857 #if SIMULATE_ERRORS
1858         static int error_sim_count = 0;
1859 #endif
1860         u16 bcount;
1861         u8 stat, ireason;
1862
1863 #if IDETAPE_DEBUG_LOG
1864         if (tape->debug_level >= 4)
1865                 printk(KERN_INFO "ide-tape: Reached idetape_pc_intr "
1866                                 "interrupt handler\n");
1867 #endif /* IDETAPE_DEBUG_LOG */
1868
1869         /* Clear the interrupt */
1870         stat = hwif->INB(IDE_STATUS_REG);
1871
1872         if (test_bit(PC_DMA_IN_PROGRESS, &pc->flags)) {
1873                 if (hwif->ide_dma_end(drive) || (stat & ERR_STAT)) {
1874                         /*
1875                          * A DMA error is sometimes expected. For example,
1876                          * if the tape is crossing a filemark during a
1877                          * READ command, it will issue an irq and position
1878                          * itself before the filemark, so that only a partial
1879                          * data transfer will occur (which causes the DMA
1880                          * error). In that case, we will later ask the tape
1881                          * how much bytes of the original request were
1882                          * actually transferred (we can't receive that
1883                          * information from the DMA engine on most chipsets).
1884                          */
1885
1886                         /*
1887                          * On the contrary, a DMA error is never expected;
1888                          * it usually indicates a hardware error or abort.
1889                          * If the tape crosses a filemark during a READ
1890                          * command, it will issue an irq and position itself
1891                          * after the filemark (not before). Only a partial
1892                          * data transfer will occur, but no DMA error.
1893                          * (AS, 19 Apr 2001)
1894                          */
1895                         set_bit(PC_DMA_ERROR, &pc->flags);
1896                 } else {
1897                         pc->actually_transferred = pc->request_transfer;
1898                         idetape_update_buffers(pc);
1899                 }
1900 #if IDETAPE_DEBUG_LOG
1901                 if (tape->debug_level >= 4)
1902                         printk(KERN_INFO "ide-tape: DMA finished\n");
1903 #endif /* IDETAPE_DEBUG_LOG */
1904         }
1905
1906         /* No more interrupts */
1907         if ((stat & DRQ_STAT) == 0) {
1908 #if IDETAPE_DEBUG_LOG
1909                 if (tape->debug_level >= 2)
1910                         printk(KERN_INFO "ide-tape: Packet command completed, %d bytes transferred\n", pc->actually_transferred);
1911 #endif /* IDETAPE_DEBUG_LOG */
1912                 clear_bit(PC_DMA_IN_PROGRESS, &pc->flags);
1913
1914                 local_irq_enable();
1915
1916 #if SIMULATE_ERRORS
1917                 if ((pc->c[0] == IDETAPE_WRITE_CMD ||
1918                      pc->c[0] == IDETAPE_READ_CMD) &&
1919                     (++error_sim_count % 100) == 0) {
1920                         printk(KERN_INFO "ide-tape: %s: simulating error\n",
1921                                 tape->name);
1922                         stat |= ERR_STAT;
1923                 }
1924 #endif
1925                 if ((stat & ERR_STAT) && pc->c[0] == IDETAPE_REQUEST_SENSE_CMD)
1926                         stat &= ~ERR_STAT;
1927                 if ((stat & ERR_STAT) || test_bit(PC_DMA_ERROR, &pc->flags)) {
1928                         /* Error detected */
1929 #if IDETAPE_DEBUG_LOG
1930                         if (tape->debug_level >= 1)
1931                                 printk(KERN_INFO "ide-tape: %s: I/O error\n",
1932                                         tape->name);
1933 #endif /* IDETAPE_DEBUG_LOG */
1934                         if (pc->c[0] == IDETAPE_REQUEST_SENSE_CMD) {
1935                                 printk(KERN_ERR "ide-tape: I/O error in request sense command\n");
1936                                 return ide_do_reset(drive);
1937                         }
1938 #if IDETAPE_DEBUG_LOG
1939                         if (tape->debug_level >= 1)
1940                                 printk(KERN_INFO "ide-tape: [cmd %x]: check condition\n", pc->c[0]);
1941 #endif
1942                         /* Retry operation */
1943                         return idetape_retry_pc(drive);
1944                 }
1945                 pc->error = 0;
1946                 if (test_bit(PC_WAIT_FOR_DSC, &pc->flags) &&
1947                     (stat & SEEK_STAT) == 0) {
1948                         /* Media access command */
1949                         tape->dsc_polling_start = jiffies;
1950                         tape->dsc_polling_frequency = IDETAPE_DSC_MA_FAST;
1951                         tape->dsc_timeout = jiffies + IDETAPE_DSC_MA_TIMEOUT;
1952                         /* Allow ide.c to handle other requests */
1953                         idetape_postpone_request(drive);
1954                         return ide_stopped;
1955                 }
1956                 if (tape->failed_pc == pc)
1957                         tape->failed_pc = NULL;
1958                 /* Command finished - Call the callback function */
1959                 return pc->callback(drive);
1960         }
1961         if (test_and_clear_bit(PC_DMA_IN_PROGRESS, &pc->flags)) {
1962                 printk(KERN_ERR "ide-tape: The tape wants to issue more "
1963                                 "interrupts in DMA mode\n");
1964                 printk(KERN_ERR "ide-tape: DMA disabled, reverting to PIO\n");
1965                 ide_dma_off(drive);
1966                 return ide_do_reset(drive);
1967         }
1968         /* Get the number of bytes to transfer on this interrupt. */
1969         bcount = (hwif->INB(IDE_BCOUNTH_REG) << 8) |
1970                   hwif->INB(IDE_BCOUNTL_REG);
1971
1972         ireason = hwif->INB(IDE_IREASON_REG);
1973
1974         if (ireason & CD) {
1975                 printk(KERN_ERR "ide-tape: CoD != 0 in idetape_pc_intr\n");
1976                 return ide_do_reset(drive);
1977         }
1978         if (((ireason & IO) == IO) == test_bit(PC_WRITING, &pc->flags)) {
1979                 /* Hopefully, we will never get here */
1980                 printk(KERN_ERR "ide-tape: We wanted to %s, ",
1981                                 (ireason & IO) ? "Write" : "Read");
1982                 printk(KERN_ERR "ide-tape: but the tape wants us to %s !\n",
1983                                 (ireason & IO) ? "Read" : "Write");
1984                 return ide_do_reset(drive);
1985         }
1986         if (!test_bit(PC_WRITING, &pc->flags)) {
1987                 /* Reading - Check that we have enough space */
1988                 temp = pc->actually_transferred + bcount;
1989                 if (temp > pc->request_transfer) {
1990                         if (temp > pc->buffer_size) {
1991                                 printk(KERN_ERR "ide-tape: The tape wants to send us more data than expected - discarding data\n");
1992                                 idetape_discard_data(drive, bcount);
1993                                 ide_set_handler(drive, &idetape_pc_intr, IDETAPE_WAIT_CMD, NULL);
1994                                 return ide_started;
1995                         }
1996 #if IDETAPE_DEBUG_LOG
1997                         if (tape->debug_level >= 2)
1998                                 printk(KERN_NOTICE "ide-tape: The tape wants to send us more data than expected - allowing transfer\n");
1999 #endif /* IDETAPE_DEBUG_LOG */
2000                 }
2001         }
2002         if (test_bit(PC_WRITING, &pc->flags)) {
2003                 if (pc->bh != NULL)
2004                         idetape_output_buffers(drive, pc, bcount);
2005                 else
2006                         /* Write the current buffer */
2007                         hwif->atapi_output_bytes(drive, pc->current_position,
2008                                                  bcount);
2009         } else {
2010                 if (pc->bh != NULL)
2011                         idetape_input_buffers(drive, pc, bcount);
2012                 else
2013                         /* Read the current buffer */
2014                         hwif->atapi_input_bytes(drive, pc->current_position,
2015                                                 bcount);
2016         }
2017         /* Update the current position */
2018         pc->actually_transferred += bcount;
2019         pc->current_position += bcount;
2020 #if IDETAPE_DEBUG_LOG
2021         if (tape->debug_level >= 2)
2022                 printk(KERN_INFO "ide-tape: [cmd %x] transferred %d bytes "
2023                                  "on that interrupt\n", pc->c[0], bcount);
2024 #endif
2025         /* And set the interrupt handler again */
2026         ide_set_handler(drive, &idetape_pc_intr, IDETAPE_WAIT_CMD, NULL);
2027         return ide_started;
2028 }
2029
2030 /*
2031  *      Packet Command Interface
2032  *
2033  *      The current Packet Command is available in tape->pc, and will not
2034  *      change until we finish handling it. Each packet command is associated
2035  *      with a callback function that will be called when the command is
2036  *      finished.
2037  *
2038  *      The handling will be done in three stages:
2039  *
2040  *      1.      idetape_issue_packet_command will send the packet command to the
2041  *              drive, and will set the interrupt handler to idetape_pc_intr.
2042  *
2043  *      2.      On each interrupt, idetape_pc_intr will be called. This step
2044  *              will be repeated until the device signals us that no more
2045  *              interrupts will be issued.
2046  *
2047  *      3.      ATAPI Tape media access commands have immediate status with a
2048  *              delayed process. In case of a successful initiation of a
2049  *              media access packet command, the DSC bit will be set when the
2050  *              actual execution of the command is finished.
2051  *              Since the tape drive will not issue an interrupt, we have to
2052  *              poll for this event. In this case, we define the request as
2053  *              "low priority request" by setting rq_status to
2054  *              IDETAPE_RQ_POSTPONED,   set a timer to poll for DSC and exit
2055  *              the driver.
2056  *
2057  *              ide.c will then give higher priority to requests which
2058  *              originate from the other device, until will change rq_status
2059  *              to RQ_ACTIVE.
2060  *
2061  *      4.      When the packet command is finished, it will be checked for errors.
2062  *
2063  *      5.      In case an error was found, we queue a request sense packet
2064  *              command in front of the request queue and retry the operation
2065  *              up to IDETAPE_MAX_PC_RETRIES times.
2066  *
2067  *      6.      In case no error was found, or we decided to give up and not
2068  *              to retry again, the callback function will be called and then
2069  *              we will handle the next request.
2070  *
2071  */
2072 static ide_startstop_t idetape_transfer_pc(ide_drive_t *drive)
2073 {
2074         ide_hwif_t *hwif = drive->hwif;
2075         idetape_tape_t *tape = drive->driver_data;
2076         idetape_pc_t *pc = tape->pc;
2077         int retries = 100;
2078         ide_startstop_t startstop;
2079         u8 ireason;
2080
2081         if (ide_wait_stat(&startstop,drive,DRQ_STAT,BUSY_STAT,WAIT_READY)) {
2082                 printk(KERN_ERR "ide-tape: Strange, packet command initiated yet DRQ isn't asserted\n");
2083                 return startstop;
2084         }
2085         ireason = hwif->INB(IDE_IREASON_REG);
2086         while (retries-- && ((ireason & CD) == 0 || (ireason & IO))) {
2087                 printk(KERN_ERR "ide-tape: (IO,CoD != (0,1) while issuing "
2088                                 "a packet command, retrying\n");
2089                 udelay(100);
2090                 ireason = hwif->INB(IDE_IREASON_REG);
2091                 if (retries == 0) {
2092                         printk(KERN_ERR "ide-tape: (IO,CoD != (0,1) while "
2093                                         "issuing a packet command, ignoring\n");
2094                         ireason |= CD;
2095                         ireason &= ~IO;
2096                 }
2097         }
2098         if ((ireason & CD) == 0 || (ireason & IO)) {
2099                 printk(KERN_ERR "ide-tape: (IO,CoD) != (0,1) while issuing "
2100                                 "a packet command\n");
2101                 return ide_do_reset(drive);
2102         }
2103         /* Set the interrupt routine */
2104         ide_set_handler(drive, &idetape_pc_intr, IDETAPE_WAIT_CMD, NULL);
2105 #ifdef CONFIG_BLK_DEV_IDEDMA
2106         /* Begin DMA, if necessary */
2107         if (test_bit(PC_DMA_IN_PROGRESS, &pc->flags))
2108                 hwif->dma_start(drive);
2109 #endif
2110         /* Send the actual packet */
2111         HWIF(drive)->atapi_output_bytes(drive, pc->c, 12);
2112         return ide_started;
2113 }
2114
2115 static ide_startstop_t idetape_issue_packet_command (ide_drive_t *drive, idetape_pc_t *pc)
2116 {
2117         ide_hwif_t *hwif = drive->hwif;
2118         idetape_tape_t *tape = drive->driver_data;
2119         int dma_ok = 0;
2120         u16 bcount;
2121
2122 #if IDETAPE_DEBUG_BUGS
2123         if (tape->pc->c[0] == IDETAPE_REQUEST_SENSE_CMD &&
2124             pc->c[0] == IDETAPE_REQUEST_SENSE_CMD) {
2125                 printk(KERN_ERR "ide-tape: possible ide-tape.c bug - "
2126                         "Two request sense in serial were issued\n");
2127         }
2128 #endif /* IDETAPE_DEBUG_BUGS */
2129
2130         if (tape->failed_pc == NULL && pc->c[0] != IDETAPE_REQUEST_SENSE_CMD)
2131                 tape->failed_pc = pc;
2132         /* Set the current packet command */
2133         tape->pc = pc;
2134
2135         if (pc->retries > IDETAPE_MAX_PC_RETRIES ||
2136             test_bit(PC_ABORT, &pc->flags)) {
2137                 /*
2138                  *      We will "abort" retrying a packet command in case
2139                  *      a legitimate error code was received (crossing a
2140                  *      filemark, or end of the media, for example).
2141                  */
2142                 if (!test_bit(PC_ABORT, &pc->flags)) {
2143                         if (!(pc->c[0] == IDETAPE_TEST_UNIT_READY_CMD &&
2144                               tape->sense_key == 2 && tape->asc == 4 &&
2145                              (tape->ascq == 1 || tape->ascq == 8))) {
2146                                 printk(KERN_ERR "ide-tape: %s: I/O error, "
2147                                                 "pc = %2x, key = %2x, "
2148                                                 "asc = %2x, ascq = %2x\n",
2149                                                 tape->name, pc->c[0],
2150                                                 tape->sense_key, tape->asc,
2151                                                 tape->ascq);
2152                         }
2153                         /* Giving up */
2154                         pc->error = IDETAPE_ERROR_GENERAL;
2155                 }
2156                 tape->failed_pc = NULL;
2157                 return pc->callback(drive);
2158         }
2159 #if IDETAPE_DEBUG_LOG
2160         if (tape->debug_level >= 2)
2161                 printk(KERN_INFO "ide-tape: Retry number - %d, cmd = %02X\n", pc->retries, pc->c[0]);
2162 #endif /* IDETAPE_DEBUG_LOG */
2163
2164         pc->retries++;
2165         /* We haven't transferred any data yet */
2166         pc->actually_transferred = 0;
2167         pc->current_position = pc->buffer;
2168         /* Request to transfer the entire buffer at once */
2169         bcount = pc->request_transfer;
2170
2171         if (test_and_clear_bit(PC_DMA_ERROR, &pc->flags)) {
2172                 printk(KERN_WARNING "ide-tape: DMA disabled, "
2173                                 "reverting to PIO\n");
2174                 ide_dma_off(drive);
2175         }
2176         if (test_bit(PC_DMA_RECOMMENDED, &pc->flags) && drive->using_dma)
2177                 dma_ok = !hwif->dma_setup(drive);
2178
2179         ide_pktcmd_tf_load(drive, IDE_TFLAG_NO_SELECT_MASK |
2180                            IDE_TFLAG_OUT_DEVICE, bcount, dma_ok);
2181
2182         if (dma_ok)                     /* Will begin DMA later */
2183                 set_bit(PC_DMA_IN_PROGRESS, &pc->flags);
2184         if (test_bit(IDETAPE_DRQ_INTERRUPT, &tape->flags)) {
2185                 ide_set_handler(drive, &idetape_transfer_pc, IDETAPE_WAIT_CMD, NULL);
2186                 hwif->OUTB(WIN_PACKETCMD, IDE_COMMAND_REG);
2187                 return ide_started;
2188         } else {
2189                 hwif->OUTB(WIN_PACKETCMD, IDE_COMMAND_REG);
2190                 return idetape_transfer_pc(drive);
2191         }
2192 }
2193
2194 /*
2195  *      General packet command callback function.
2196  */
2197 static ide_startstop_t idetape_pc_callback (ide_drive_t *drive)
2198 {
2199         idetape_tape_t *tape = drive->driver_data;
2200
2201 #if IDETAPE_DEBUG_LOG
2202         if (tape->debug_level >= 4)
2203                 printk(KERN_INFO "ide-tape: Reached idetape_pc_callback\n");
2204 #endif /* IDETAPE_DEBUG_LOG */
2205
2206         idetape_end_request(drive, tape->pc->error ? 0 : 1, 0);
2207         return ide_stopped;
2208 }
2209
2210 /*
2211  *      A mode sense command is used to "sense" tape parameters.
2212  */
2213 static void idetape_create_mode_sense_cmd (idetape_pc_t *pc, u8 page_code)
2214 {
2215         idetape_init_pc(pc);
2216         pc->c[0] = IDETAPE_MODE_SENSE_CMD;
2217         if (page_code != IDETAPE_BLOCK_DESCRIPTOR)
2218                 pc->c[1] = 8;   /* DBD = 1 - Don't return block descriptors */
2219         pc->c[2] = page_code;
2220         /*
2221          * Changed pc->c[3] to 0 (255 will at best return unused info).
2222          *
2223          * For SCSI this byte is defined as subpage instead of high byte
2224          * of length and some IDE drives seem to interpret it this way
2225          * and return an error when 255 is used.
2226          */
2227         pc->c[3] = 0;
2228         pc->c[4] = 255;         /* (We will just discard data in that case) */
2229         if (page_code == IDETAPE_BLOCK_DESCRIPTOR)
2230                 pc->request_transfer = 12;
2231         else if (page_code == IDETAPE_CAPABILITIES_PAGE)
2232                 pc->request_transfer = 24;
2233         else
2234                 pc->request_transfer = 50;
2235         pc->callback = &idetape_pc_callback;
2236 }
2237
2238 static void calculate_speeds(ide_drive_t *drive)
2239 {
2240         idetape_tape_t *tape = drive->driver_data;
2241         int full = 125, empty = 75;
2242
2243         if (time_after(jiffies, tape->controlled_pipeline_head_time + 120 * HZ)) {
2244                 tape->controlled_previous_pipeline_head = tape->controlled_last_pipeline_head;
2245                 tape->controlled_previous_head_time = tape->controlled_pipeline_head_time;
2246                 tape->controlled_last_pipeline_head = tape->pipeline_head;
2247                 tape->controlled_pipeline_head_time = jiffies;
2248         }
2249         if (time_after(jiffies, tape->controlled_pipeline_head_time + 60 * HZ))
2250                 tape->controlled_pipeline_head_speed = (tape->pipeline_head - tape->controlled_last_pipeline_head) * 32 * HZ / (jiffies - tape->controlled_pipeline_head_time);
2251         else if (time_after(jiffies, tape->controlled_previous_head_time))
2252                 tape->controlled_pipeline_head_speed = (tape->pipeline_head - tape->controlled_previous_pipeline_head) * 32 * HZ / (jiffies - tape->controlled_previous_head_time);
2253
2254         if (tape->nr_pending_stages < tape->max_stages /*- 1 */) {
2255                 /* -1 for read mode error recovery */
2256                 if (time_after(jiffies, tape->uncontrolled_previous_head_time + 10 * HZ)) {
2257                         tape->uncontrolled_pipeline_head_time = jiffies;
2258                         tape->uncontrolled_pipeline_head_speed = (tape->pipeline_head - tape->uncontrolled_previous_pipeline_head) * 32 * HZ / (jiffies - tape->uncontrolled_previous_head_time);
2259                 }
2260         } else {
2261                 tape->uncontrolled_previous_head_time = jiffies;
2262                 tape->uncontrolled_previous_pipeline_head = tape->pipeline_head;
2263                 if (time_after(jiffies, tape->uncontrolled_pipeline_head_time + 30 * HZ)) {
2264                         tape->uncontrolled_pipeline_head_time = jiffies;
2265                 }
2266         }
2267         tape->pipeline_head_speed = max(tape->uncontrolled_pipeline_head_speed, tape->controlled_pipeline_head_speed);
2268         if (tape->speed_control == 0) {
2269                 tape->max_insert_speed = 5000;
2270         } else if (tape->speed_control == 1) {
2271                 if (tape->nr_pending_stages >= tape->max_stages / 2)
2272                         tape->max_insert_speed = tape->pipeline_head_speed +
2273                                 (1100 - tape->pipeline_head_speed) * 2 * (tape->nr_pending_stages - tape->max_stages / 2) / tape->max_stages;
2274                 else
2275                         tape->max_insert_speed = 500 +
2276                                 (tape->pipeline_head_speed - 500) * 2 * tape->nr_pending_stages / tape->max_stages;
2277                 if (tape->nr_pending_stages >= tape->max_stages * 99 / 100)
2278                         tape->max_insert_speed = 5000;
2279         } else if (tape->speed_control == 2) {
2280                 tape->max_insert_speed = tape->pipeline_head_speed * empty / 100 +
2281                         (tape->pipeline_head_speed * full / 100 - tape->pipeline_head_speed * empty / 100) * tape->nr_pending_stages / tape->max_stages;
2282         } else
2283                 tape->max_insert_speed = tape->speed_control;
2284         tape->max_insert_speed = max(tape->max_insert_speed, 500);
2285 }
2286
2287 static ide_startstop_t idetape_media_access_finished (ide_drive_t *drive)
2288 {
2289         idetape_tape_t *tape = drive->driver_data;
2290         idetape_pc_t *pc = tape->pc;
2291         u8 stat;
2292
2293         stat = drive->hwif->INB(IDE_STATUS_REG);
2294         if (stat & SEEK_STAT) {
2295                 if (stat & ERR_STAT) {
2296                         /* Error detected */
2297                         if (pc->c[0] != IDETAPE_TEST_UNIT_READY_CMD)
2298                                 printk(KERN_ERR "ide-tape: %s: I/O error, ",
2299                                                 tape->name);
2300                         /* Retry operation */
2301                         return idetape_retry_pc(drive);
2302                 }
2303                 pc->error = 0;
2304                 if (tape->failed_pc == pc)
2305                         tape->failed_pc = NULL;
2306         } else {
2307                 pc->error = IDETAPE_ERROR_GENERAL;
2308                 tape->failed_pc = NULL;
2309         }
2310         return pc->callback(drive);
2311 }
2312
2313 static ide_startstop_t idetape_rw_callback (ide_drive_t *drive)
2314 {
2315         idetape_tape_t *tape = drive->driver_data;
2316         struct request *rq = HWGROUP(drive)->rq;
2317         int blocks = tape->pc->actually_transferred / tape->tape_block_size;
2318
2319         tape->avg_size += blocks * tape->tape_block_size;
2320         tape->insert_size += blocks * tape->tape_block_size;
2321         if (tape->insert_size > 1024 * 1024)
2322                 tape->measure_insert_time = 1;
2323         if (tape->measure_insert_time) {
2324                 tape->measure_insert_time = 0;
2325                 tape->insert_time = jiffies;
2326                 tape->insert_size = 0;
2327         }
2328         if (time_after(jiffies, tape->insert_time))
2329                 tape->insert_speed = tape->insert_size / 1024 * HZ / (jiffies - tape->insert_time);
2330         if (time_after_eq(jiffies, tape->avg_time + HZ)) {
2331                 tape->avg_speed = tape->avg_size * HZ / (jiffies - tape->avg_time) / 1024;
2332                 tape->avg_size = 0;
2333                 tape->avg_time = jiffies;
2334         }
2335
2336 #if IDETAPE_DEBUG_LOG
2337         if (tape->debug_level >= 4)
2338                 printk(KERN_INFO "ide-tape: Reached idetape_rw_callback\n");
2339 #endif /* IDETAPE_DEBUG_LOG */
2340
2341         tape->first_frame_position += blocks;
2342         rq->current_nr_sectors -= blocks;
2343
2344         if (!tape->pc->error)
2345                 idetape_end_request(drive, 1, 0);
2346         else
2347                 idetape_end_request(drive, tape->pc->error, 0);
2348         return ide_stopped;
2349 }
2350
2351 static void idetape_create_read_cmd(idetape_tape_t *tape, idetape_pc_t *pc, unsigned int length, struct idetape_bh *bh)
2352 {
2353         idetape_init_pc(pc);
2354         pc->c[0] = IDETAPE_READ_CMD;
2355         put_unaligned(htonl(length), (unsigned int *) &pc->c[1]);
2356         pc->c[1] = 1;
2357         pc->callback = &idetape_rw_callback;
2358         pc->bh = bh;
2359         atomic_set(&bh->b_count, 0);
2360         pc->buffer = NULL;
2361         pc->request_transfer = pc->buffer_size = length * tape->tape_block_size;
2362         if (pc->request_transfer == tape->stage_size)
2363                 set_bit(PC_DMA_RECOMMENDED, &pc->flags);
2364 }
2365
2366 static void idetape_create_read_buffer_cmd(idetape_tape_t *tape, idetape_pc_t *pc, unsigned int length, struct idetape_bh *bh)
2367 {
2368         int size = 32768;
2369         struct idetape_bh *p = bh;
2370
2371         idetape_init_pc(pc);
2372         pc->c[0] = IDETAPE_READ_BUFFER_CMD;
2373         pc->c[1] = IDETAPE_RETRIEVE_FAULTY_BLOCK;
2374         pc->c[7] = size >> 8;
2375         pc->c[8] = size & 0xff;
2376         pc->callback = &idetape_pc_callback;
2377         pc->bh = bh;
2378         atomic_set(&bh->b_count, 0);
2379         pc->buffer = NULL;
2380         while (p) {
2381                 atomic_set(&p->b_count, 0);
2382                 p = p->b_reqnext;
2383         }
2384         pc->request_transfer = pc->buffer_size = size;
2385 }
2386
2387 static void idetape_create_write_cmd(idetape_tape_t *tape, idetape_pc_t *pc, unsigned int length, struct idetape_bh *bh)
2388 {
2389         idetape_init_pc(pc);
2390         pc->c[0] = IDETAPE_WRITE_CMD;
2391         put_unaligned(htonl(length), (unsigned int *) &pc->c[1]);
2392         pc->c[1] = 1;
2393         pc->callback = &idetape_rw_callback;
2394         set_bit(PC_WRITING, &pc->flags);
2395         pc->bh = bh;
2396         pc->b_data = bh->b_data;
2397         pc->b_count = atomic_read(&bh->b_count);
2398         pc->buffer = NULL;
2399         pc->request_transfer = pc->buffer_size = length * tape->tape_block_size;
2400         if (pc->request_transfer == tape->stage_size)
2401                 set_bit(PC_DMA_RECOMMENDED, &pc->flags);
2402 }
2403
2404 /*
2405  * idetape_do_request is our request handling function.
2406  */
2407 static ide_startstop_t idetape_do_request(ide_drive_t *drive,
2408                                           struct request *rq, sector_t block)
2409 {
2410         idetape_tape_t *tape = drive->driver_data;
2411         idetape_pc_t *pc = NULL;
2412         struct request *postponed_rq = tape->postponed_rq;
2413         u8 stat;
2414
2415 #if IDETAPE_DEBUG_LOG
2416 #if 0
2417         if (tape->debug_level >= 5)
2418                 printk(KERN_INFO "ide-tape:  %d, "
2419                         "dev: %s, cmd: %ld, errors: %d\n",
2420                          rq->rq_disk->disk_name, rq->cmd[0], rq->errors);
2421 #endif
2422         if (tape->debug_level >= 2)
2423                 printk(KERN_INFO "ide-tape: sector: %ld, "
2424                         "nr_sectors: %ld, current_nr_sectors: %d\n",
2425                         rq->sector, rq->nr_sectors, rq->current_nr_sectors);
2426 #endif /* IDETAPE_DEBUG_LOG */
2427
2428         if (!blk_special_request(rq)) {
2429                 /*
2430                  * We do not support buffer cache originated requests.
2431                  */
2432                 printk(KERN_NOTICE "ide-tape: %s: Unsupported request in "
2433                         "request queue (%d)\n", drive->name, rq->cmd_type);
2434                 ide_end_request(drive, 0, 0);
2435                 return ide_stopped;
2436         }
2437
2438         /*
2439          *      Retry a failed packet command
2440          */
2441         if (tape->failed_pc != NULL &&
2442             tape->pc->c[0] == IDETAPE_REQUEST_SENSE_CMD) {
2443                 return idetape_issue_packet_command(drive, tape->failed_pc);
2444         }
2445 #if IDETAPE_DEBUG_BUGS
2446         if (postponed_rq != NULL)
2447                 if (rq != postponed_rq) {
2448                         printk(KERN_ERR "ide-tape: ide-tape.c bug - "
2449                                         "Two DSC requests were queued\n");
2450                         idetape_end_request(drive, 0, 0);
2451                         return ide_stopped;
2452                 }
2453 #endif /* IDETAPE_DEBUG_BUGS */
2454
2455         tape->postponed_rq = NULL;
2456
2457         /*
2458          * If the tape is still busy, postpone our request and service
2459          * the other device meanwhile.
2460          */
2461         stat = drive->hwif->INB(IDE_STATUS_REG);
2462
2463         if (!drive->dsc_overlap && !(rq->cmd[0] & REQ_IDETAPE_PC2))
2464                 set_bit(IDETAPE_IGNORE_DSC, &tape->flags);
2465
2466         if (drive->post_reset == 1) {
2467                 set_bit(IDETAPE_IGNORE_DSC, &tape->flags);
2468                 drive->post_reset = 0;
2469         }
2470
2471         if (tape->tape_still_time > 100 && tape->tape_still_time < 200)
2472                 tape->measure_insert_time = 1;
2473         if (time_after(jiffies, tape->insert_time))
2474                 tape->insert_speed = tape->insert_size / 1024 * HZ / (jiffies - tape->insert_time);
2475         calculate_speeds(drive);
2476         if (!test_and_clear_bit(IDETAPE_IGNORE_DSC, &tape->flags) &&
2477             (stat & SEEK_STAT) == 0) {
2478                 if (postponed_rq == NULL) {
2479                         tape->dsc_polling_start = jiffies;
2480                         tape->dsc_polling_frequency = tape->best_dsc_rw_frequency;
2481                         tape->dsc_timeout = jiffies + IDETAPE_DSC_RW_TIMEOUT;
2482                 } else if (time_after(jiffies, tape->dsc_timeout)) {
2483                         printk(KERN_ERR "ide-tape: %s: DSC timeout\n",
2484                                 tape->name);
2485                         if (rq->cmd[0] & REQ_IDETAPE_PC2) {
2486                                 idetape_media_access_finished(drive);
2487                                 return ide_stopped;
2488                         } else {
2489                                 return ide_do_reset(drive);
2490                         }
2491                 } else if (time_after(jiffies, tape->dsc_polling_start + IDETAPE_DSC_MA_THRESHOLD))
2492                         tape->dsc_polling_frequency = IDETAPE_DSC_MA_SLOW;
2493                 idetape_postpone_request(drive);
2494                 return ide_stopped;
2495         }
2496         if (rq->cmd[0] & REQ_IDETAPE_READ) {
2497                 tape->buffer_head++;
2498                 tape->postpone_cnt = 0;
2499                 pc = idetape_next_pc_storage(drive);
2500                 idetape_create_read_cmd(tape, pc, rq->current_nr_sectors, (struct idetape_bh *)rq->special);
2501                 goto out;
2502         }
2503         if (rq->cmd[0] & REQ_IDETAPE_WRITE) {
2504                 tape->buffer_head++;
2505                 tape->postpone_cnt = 0;
2506                 pc = idetape_next_pc_storage(drive);
2507                 idetape_create_write_cmd(tape, pc, rq->current_nr_sectors, (struct idetape_bh *)rq->special);
2508                 goto out;
2509         }
2510         if (rq->cmd[0] & REQ_IDETAPE_READ_BUFFER) {
2511                 tape->postpone_cnt = 0;
2512                 pc = idetape_next_pc_storage(drive);
2513                 idetape_create_read_buffer_cmd(tape, pc, rq->current_nr_sectors, (struct idetape_bh *)rq->special);
2514                 goto out;
2515         }
2516         if (rq->cmd[0] & REQ_IDETAPE_PC1) {
2517                 pc = (idetape_pc_t *) rq->buffer;
2518                 rq->cmd[0] &= ~(REQ_IDETAPE_PC1);
2519                 rq->cmd[0] |= REQ_IDETAPE_PC2;
2520                 goto out;
2521         }
2522         if (rq->cmd[0] & REQ_IDETAPE_PC2) {
2523                 idetape_media_access_finished(drive);
2524                 return ide_stopped;
2525         }
2526         BUG();
2527 out:
2528         return idetape_issue_packet_command(drive, pc);
2529 }
2530
2531 /*
2532  *      Pipeline related functions
2533  */
2534 static inline int idetape_pipeline_active (idetape_tape_t *tape)
2535 {
2536         int rc1, rc2;
2537
2538         rc1 = test_bit(IDETAPE_PIPELINE_ACTIVE, &tape->flags);
2539         rc2 = (tape->active_data_request != NULL);
2540         return rc1;
2541 }
2542
2543 /*
2544  *      idetape_kmalloc_stage uses __get_free_page to allocate a pipeline
2545  *      stage, along with all the necessary small buffers which together make
2546  *      a buffer of size tape->stage_size (or a bit more). We attempt to
2547  *      combine sequential pages as much as possible.
2548  *
2549  *      Returns a pointer to the new allocated stage, or NULL if we
2550  *      can't (or don't want to) allocate a stage.
2551  *
2552  *      Pipeline stages are optional and are used to increase performance.
2553  *      If we can't allocate them, we'll manage without them.
2554  */
2555 static idetape_stage_t *__idetape_kmalloc_stage (idetape_tape_t *tape, int full, int clear)
2556 {
2557         idetape_stage_t *stage;
2558         struct idetape_bh *prev_bh, *bh;
2559         int pages = tape->pages_per_stage;
2560         char *b_data = NULL;
2561
2562         if ((stage = kmalloc(sizeof (idetape_stage_t),GFP_KERNEL)) == NULL)
2563                 return NULL;
2564         stage->next = NULL;
2565
2566         bh = stage->bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
2567         if (bh == NULL)
2568                 goto abort;
2569         bh->b_reqnext = NULL;
2570         if ((bh->b_data = (char *) __get_free_page (GFP_KERNEL)) == NULL)
2571                 goto abort;
2572         if (clear)
2573                 memset(bh->b_data, 0, PAGE_SIZE);
2574         bh->b_size = PAGE_SIZE;
2575         atomic_set(&bh->b_count, full ? bh->b_size : 0);
2576
2577         while (--pages) {
2578                 if ((b_data = (char *) __get_free_page (GFP_KERNEL)) == NULL)
2579                         goto abort;
2580                 if (clear)
2581                         memset(b_data, 0, PAGE_SIZE);
2582                 if (bh->b_data == b_data + PAGE_SIZE) {
2583                         bh->b_size += PAGE_SIZE;
2584                         bh->b_data -= PAGE_SIZE;
2585                         if (full)
2586                                 atomic_add(PAGE_SIZE, &bh->b_count);
2587                         continue;
2588                 }
2589                 if (b_data == bh->b_data + bh->b_size) {
2590                         bh->b_size += PAGE_SIZE;
2591                         if (full)
2592                                 atomic_add(PAGE_SIZE, &bh->b_count);
2593                         continue;
2594                 }
2595                 prev_bh = bh;
2596                 if ((bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL)) == NULL) {
2597                         free_page((unsigned long) b_data);
2598                         goto abort;
2599                 }
2600                 bh->b_reqnext = NULL;
2601                 bh->b_data = b_data;
2602                 bh->b_size = PAGE_SIZE;
2603                 atomic_set(&bh->b_count, full ? bh->b_size : 0);
2604                 prev_bh->b_reqnext = bh;
2605         }
2606         bh->b_size -= tape->excess_bh_size;
2607         if (full)
2608                 atomic_sub(tape->excess_bh_size, &bh->b_count);
2609         return stage;
2610 abort:
2611         __idetape_kfree_stage(stage);
2612         return NULL;
2613 }
2614
2615 static idetape_stage_t *idetape_kmalloc_stage (idetape_tape_t *tape)
2616 {
2617         idetape_stage_t *cache_stage = tape->cache_stage;
2618
2619 #if IDETAPE_DEBUG_LOG
2620         if (tape->debug_level >= 4)
2621                 printk(KERN_INFO "ide-tape: Reached idetape_kmalloc_stage\n");
2622 #endif /* IDETAPE_DEBUG_LOG */
2623
2624         if (tape->nr_stages >= tape->max_stages)
2625                 return NULL;
2626         if (cache_stage != NULL) {
2627                 tape->cache_stage = NULL;
2628                 return cache_stage;
2629         }
2630         return __idetape_kmalloc_stage(tape, 0, 0);
2631 }
2632
2633 static int idetape_copy_stage_from_user (idetape_tape_t *tape, idetape_stage_t *stage, const char __user *buf, int n)
2634 {
2635         struct idetape_bh *bh = tape->bh;
2636         int count;
2637         int ret = 0;
2638
2639         while (n) {
2640 #if IDETAPE_DEBUG_BUGS
2641                 if (bh == NULL) {
2642                         printk(KERN_ERR "ide-tape: bh == NULL in "
2643                                 "idetape_copy_stage_from_user\n");
2644                         return 1;
2645                 }
2646 #endif /* IDETAPE_DEBUG_BUGS */
2647                 count = min((unsigned int)(bh->b_size - atomic_read(&bh->b_count)), (unsigned int)n);
2648                 if (copy_from_user(bh->b_data + atomic_read(&bh->b_count), buf, count))
2649                         ret = 1;
2650                 n -= count;
2651                 atomic_add(count, &bh->b_count);
2652                 buf += count;
2653                 if (atomic_read(&bh->b_count) == bh->b_size) {
2654                         bh = bh->b_reqnext;
2655                         if (bh)
2656                                 atomic_set(&bh->b_count, 0);
2657                 }
2658         }
2659         tape->bh = bh;
2660         return ret;
2661 }
2662
2663 static int idetape_copy_stage_to_user (idetape_tape_t *tape, char __user *buf, idetape_stage_t *stage, int n)
2664 {
2665         struct idetape_bh *bh = tape->bh;
2666         int count;
2667         int ret = 0;
2668
2669         while (n) {
2670 #if IDETAPE_DEBUG_BUGS
2671                 if (bh == NULL) {
2672                         printk(KERN_ERR "ide-tape: bh == NULL in "
2673                                 "idetape_copy_stage_to_user\n");
2674                         return 1;
2675                 }
2676 #endif /* IDETAPE_DEBUG_BUGS */
2677                 count = min(tape->b_count, n);
2678                 if  (copy_to_user(buf, tape->b_data, count))
2679                         ret = 1;
2680                 n -= count;
2681                 tape->b_data += count;
2682                 tape->b_count -= count;
2683                 buf += count;
2684                 if (!tape->b_count) {
2685                         tape->bh = bh = bh->b_reqnext;
2686                         if (bh) {
2687                                 tape->b_data = bh->b_data;
2688                                 tape->b_count = atomic_read(&bh->b_count);
2689                         }
2690                 }
2691         }
2692         return ret;
2693 }
2694
2695 static void idetape_init_merge_stage (idetape_tape_t *tape)
2696 {
2697         struct idetape_bh *bh = tape->merge_stage->bh;
2698
2699         tape->bh = bh;
2700         if (tape->chrdev_direction == idetape_direction_write)
2701                 atomic_set(&bh->b_count, 0);
2702         else {
2703                 tape->b_data = bh->b_data;
2704                 tape->b_count = atomic_read(&bh->b_count);
2705         }
2706 }
2707
2708 static void idetape_switch_buffers (idetape_tape_t *tape, idetape_stage_t *stage)
2709 {
2710         struct idetape_bh *tmp;
2711
2712         tmp = stage->bh;
2713         stage->bh = tape->merge_stage->bh;
2714         tape->merge_stage->bh = tmp;
2715         idetape_init_merge_stage(tape);
2716 }
2717
2718 /*
2719  *      idetape_add_stage_tail adds a new stage at the end of the pipeline.
2720  */
2721 static void idetape_add_stage_tail (ide_drive_t *drive,idetape_stage_t *stage)
2722 {
2723         idetape_tape_t *tape = drive->driver_data;
2724         unsigned long flags;
2725
2726 #if IDETAPE_DEBUG_LOG
2727         if (tape->debug_level >= 4)
2728                 printk (KERN_INFO "ide-tape: Reached idetape_add_stage_tail\n");
2729 #endif /* IDETAPE_DEBUG_LOG */
2730         spin_lock_irqsave(&tape->spinlock, flags);
2731         stage->next = NULL;
2732         if (tape->last_stage != NULL)
2733                 tape->last_stage->next=stage;
2734         else
2735                 tape->first_stage = tape->next_stage=stage;
2736         tape->last_stage = stage;
2737         if (tape->next_stage == NULL)
2738                 tape->next_stage = tape->last_stage;
2739         tape->nr_stages++;
2740         tape->nr_pending_stages++;
2741         spin_unlock_irqrestore(&tape->spinlock, flags);
2742 }
2743
2744 /*
2745  *      idetape_wait_for_request installs a completion in a pending request
2746  *      and sleeps until it is serviced.
2747  *
2748  *      The caller should ensure that the request will not be serviced
2749  *      before we install the completion (usually by disabling interrupts).
2750  */
2751 static void idetape_wait_for_request (ide_drive_t *drive, struct request *rq)
2752 {
2753         DECLARE_COMPLETION_ONSTACK(wait);
2754         idetape_tape_t *tape = drive->driver_data;
2755
2756 #if IDETAPE_DEBUG_BUGS
2757         if (rq == NULL || !blk_special_request(rq)) {
2758                 printk (KERN_ERR "ide-tape: bug: Trying to sleep on non-valid request\n");
2759                 return;
2760         }
2761 #endif /* IDETAPE_DEBUG_BUGS */
2762         rq->end_io_data = &wait;
2763         rq->end_io = blk_end_sync_rq;
2764         spin_unlock_irq(&tape->spinlock);
2765         wait_for_completion(&wait);
2766         /* The stage and its struct request have been deallocated */
2767         spin_lock_irq(&tape->spinlock);
2768 }
2769
2770 static ide_startstop_t idetape_read_position_callback (ide_drive_t *drive)
2771 {
2772         idetape_tape_t *tape = drive->driver_data;
2773         idetape_read_position_result_t *result;
2774
2775 #if IDETAPE_DEBUG_LOG
2776         if (tape->debug_level >= 4)
2777                 printk(KERN_INFO "ide-tape: Reached idetape_read_position_callback\n");
2778 #endif /* IDETAPE_DEBUG_LOG */
2779
2780         if (!tape->pc->error) {
2781                 result = (idetape_read_position_result_t *) tape->pc->buffer;
2782 #if IDETAPE_DEBUG_LOG
2783                 if (tape->debug_level >= 2)
2784                         printk(KERN_INFO "ide-tape: BOP - %s\n",result->bop ? "Yes":"No");
2785                 if (tape->debug_level >= 2)
2786                         printk(KERN_INFO "ide-tape: EOP - %s\n",result->eop ? "Yes":"No");
2787 #endif /* IDETAPE_DEBUG_LOG */
2788                 if (result->bpu) {
2789                         printk(KERN_INFO "ide-tape: Block location is unknown to the tape\n");
2790                         clear_bit(IDETAPE_ADDRESS_VALID, &tape->flags);
2791                         idetape_end_request(drive, 0, 0);
2792                 } else {
2793 #if IDETAPE_DEBUG_LOG
2794                         if (tape->debug_level >= 2)
2795                                 printk(KERN_INFO "ide-tape: Block Location - %u\n", ntohl(result->first_block));
2796 #endif /* IDETAPE_DEBUG_LOG */
2797                         tape->partition = result->partition;
2798                         tape->first_frame_position = ntohl(result->first_block);
2799                         tape->last_frame_position = ntohl(result->last_block);
2800                         tape->blocks_in_buffer = result->blocks_in_buffer[2];
2801                         set_bit(IDETAPE_ADDRESS_VALID, &tape->flags);
2802                         idetape_end_request(drive, 1, 0);
2803                 }
2804         } else {
2805                 idetape_end_request(drive, 0, 0);
2806         }
2807         return ide_stopped;
2808 }
2809
2810 /*
2811  *      idetape_create_write_filemark_cmd will:
2812  *
2813  *              1.      Write a filemark if write_filemark=1.
2814  *              2.      Flush the device buffers without writing a filemark
2815  *                      if write_filemark=0.
2816  *
2817  */
2818 static void idetape_create_write_filemark_cmd (ide_drive_t *drive, idetape_pc_t *pc,int write_filemark)
2819 {
2820         idetape_init_pc(pc);
2821         pc->c[0] = IDETAPE_WRITE_FILEMARK_CMD;
2822         pc->c[4] = write_filemark;
2823         set_bit(PC_WAIT_FOR_DSC, &pc->flags);
2824         pc->callback = &idetape_pc_callback;
2825 }
2826
2827 static void idetape_create_test_unit_ready_cmd(idetape_pc_t *pc)
2828 {
2829         idetape_init_pc(pc);
2830         pc->c[0] = IDETAPE_TEST_UNIT_READY_CMD;
2831         pc->callback = &idetape_pc_callback;
2832 }
2833
2834 /*
2835  *      idetape_queue_pc_tail is based on the following functions:
2836  *
2837  *      ide_do_drive_cmd from ide.c
2838  *      cdrom_queue_request and cdrom_queue_packet_command from ide-cd.c
2839  *
2840  *      We add a special packet command request to the tail of the request
2841  *      queue, and wait for it to be serviced.
2842  *
2843  *      This is not to be called from within the request handling part
2844  *      of the driver ! We allocate here data in the stack, and it is valid
2845  *      until the request is finished. This is not the case for the bottom
2846  *      part of the driver, where we are always leaving the functions to wait
2847  *      for an interrupt or a timer event.
2848  *
2849  *      From the bottom part of the driver, we should allocate safe memory
2850  *      using idetape_next_pc_storage and idetape_next_rq_storage, and add
2851  *      the request to the request list without waiting for it to be serviced !
2852  *      In that case, we usually use idetape_queue_pc_head.
2853  */
2854 static int __idetape_queue_pc_tail (ide_drive_t *drive, idetape_pc_t *pc)
2855 {
2856         struct ide_tape_obj *tape = drive->driver_data;
2857         struct request rq;
2858
2859         idetape_init_rq(&rq, REQ_IDETAPE_PC1);
2860         rq.buffer = (char *) pc;
2861         rq.rq_disk = tape->disk;
2862         return ide_do_drive_cmd(drive, &rq, ide_wait);
2863 }
2864
2865 static void idetape_create_load_unload_cmd (ide_drive_t *drive, idetape_pc_t *pc,int cmd)
2866 {
2867         idetape_init_pc(pc);
2868         pc->c[0] = IDETAPE_LOAD_UNLOAD_CMD;
2869         pc->c[4] = cmd;
2870         set_bit(PC_WAIT_FOR_DSC, &pc->flags);
2871         pc->callback = &idetape_pc_callback;
2872 }
2873
2874 static int idetape_wait_ready(ide_drive_t *drive, unsigned long timeout)
2875 {
2876         idetape_tape_t *tape = drive->driver_data;
2877         idetape_pc_t pc;
2878         int load_attempted = 0;
2879
2880         /*
2881          * Wait for the tape to become ready
2882          */
2883         set_bit(IDETAPE_MEDIUM_PRESENT, &tape->flags);
2884         timeout += jiffies;
2885         while (time_before(jiffies, timeout)) {
2886                 idetape_create_test_unit_ready_cmd(&pc);
2887                 if (!__idetape_queue_pc_tail(drive, &pc))
2888                         return 0;
2889                 if ((tape->sense_key == 2 && tape->asc == 4 && tape->ascq == 2)
2890                     || (tape->asc == 0x3A)) {   /* no media */
2891                         if (load_attempted)
2892                                 return -ENOMEDIUM;
2893                         idetape_create_load_unload_cmd(drive, &pc, IDETAPE_LU_LOAD_MASK);
2894                         __idetape_queue_pc_tail(drive, &pc);
2895                         load_attempted = 1;
2896                 /* not about to be ready */
2897                 } else if (!(tape->sense_key == 2 && tape->asc == 4 &&
2898                              (tape->ascq == 1 || tape->ascq == 8)))
2899                         return -EIO;
2900                 msleep(100);
2901         }
2902         return -EIO;
2903 }
2904
2905 static int idetape_queue_pc_tail (ide_drive_t *drive,idetape_pc_t *pc)
2906 {
2907         return __idetape_queue_pc_tail(drive, pc);
2908 }
2909
2910 static int idetape_flush_tape_buffers (ide_drive_t *drive)
2911 {
2912         idetape_pc_t pc;
2913         int rc;
2914
2915         idetape_create_write_filemark_cmd(drive, &pc, 0);
2916         if ((rc = idetape_queue_pc_tail(drive, &pc)))
2917                 return rc;
2918         idetape_wait_ready(drive, 60 * 5 * HZ);
2919         return 0;
2920 }
2921
2922 static void idetape_create_read_position_cmd (idetape_pc_t *pc)
2923 {
2924         idetape_init_pc(pc);
2925         pc->c[0] = IDETAPE_READ_POSITION_CMD;
2926         pc->request_transfer = 20;
2927         pc->callback = &idetape_read_position_callback;
2928 }
2929
2930 static int idetape_read_position (ide_drive_t *drive)
2931 {
2932         idetape_tape_t *tape = drive->driver_data;
2933         idetape_pc_t pc;
2934         int position;
2935
2936 #if IDETAPE_DEBUG_LOG
2937         if (tape->debug_level >= 4)
2938                 printk(KERN_INFO "ide-tape: Reached idetape_read_position\n");
2939 #endif /* IDETAPE_DEBUG_LOG */
2940
2941         idetape_create_read_position_cmd(&pc);
2942         if (idetape_queue_pc_tail(drive, &pc))
2943                 return -1;
2944         position = tape->first_frame_position;
2945         return position;
2946 }
2947
2948 static void idetape_create_locate_cmd (ide_drive_t *drive, idetape_pc_t *pc, unsigned int block, u8 partition, int skip)
2949 {
2950         idetape_init_pc(pc);
2951         pc->c[0] = IDETAPE_LOCATE_CMD;
2952         pc->c[1] = 2;
2953         put_unaligned(htonl(block), (unsigned int *) &pc->c[3]);
2954         pc->c[8] = partition;
2955         set_bit(PC_WAIT_FOR_DSC, &pc->flags);
2956         pc->callback = &idetape_pc_callback;
2957 }
2958
2959 static int idetape_create_prevent_cmd (ide_drive_t *drive, idetape_pc_t *pc, int prevent)
2960 {
2961         idetape_tape_t *tape = drive->driver_data;
2962
2963         if (!tape->capabilities.lock)
2964                 return 0;
2965
2966         idetape_init_pc(pc);
2967         pc->c[0] = IDETAPE_PREVENT_CMD;
2968         pc->c[4] = prevent;
2969         pc->callback = &idetape_pc_callback;
2970         return 1;
2971 }
2972
2973 static int __idetape_discard_read_pipeline (ide_drive_t *drive)
2974 {
2975         idetape_tape_t *tape = drive->driver_data;
2976         unsigned long flags;
2977         int cnt;
2978
2979         if (tape->chrdev_direction != idetape_direction_read)
2980                 return 0;
2981
2982         /* Remove merge stage. */
2983         cnt = tape->merge_stage_size / tape->tape_block_size;
2984         if (test_and_clear_bit(IDETAPE_FILEMARK, &tape->flags))
2985                 ++cnt;          /* Filemarks count as 1 sector */
2986         tape->merge_stage_size = 0;
2987         if (tape->merge_stage != NULL) {
2988                 __idetape_kfree_stage(tape->merge_stage);
2989                 tape->merge_stage = NULL;
2990         }
2991
2992         /* Clear pipeline flags. */
2993         clear_bit(IDETAPE_PIPELINE_ERROR, &tape->flags);
2994         tape->chrdev_direction = idetape_direction_none;
2995
2996         /* Remove pipeline stages. */
2997         if (tape->first_stage == NULL)
2998                 return 0;
2999
3000         spin_lock_irqsave(&tape->spinlock, flags);
3001         tape->next_stage = NULL;
3002         if (idetape_pipeline_active(tape))
3003                 idetape_wait_for_request(drive, tape->active_data_request);
3004         spin_unlock_irqrestore(&tape->spinlock, flags);
3005
3006         while (tape->first_stage != NULL) {
3007                 struct request *rq_ptr = &tape->first_stage->rq;
3008
3009                 cnt += rq_ptr->nr_sectors - rq_ptr->current_nr_sectors;
3010                 if (rq_ptr->errors == IDETAPE_ERROR_FILEMARK)
3011                         ++cnt;
3012                 idetape_remove_stage_head(drive);
3013         }
3014         tape->nr_pending_stages = 0;
3015         tape->max_stages = tape->min_pipeline;
3016         return cnt;
3017 }
3018
3019 /*
3020  *      idetape_position_tape positions the tape to the requested block
3021  *      using the LOCATE packet command. A READ POSITION command is then
3022  *      issued to check where we are positioned.
3023  *
3024  *      Like all higher level operations, we queue the commands at the tail
3025  *      of the request queue and wait for their completion.
3026  *
3027  */
3028 static int idetape_position_tape (ide_drive_t *drive, unsigned int block, u8 partition, int skip)
3029 {
3030         idetape_tape_t *tape = drive->driver_data;
3031         int retval;
3032         idetape_pc_t pc;
3033
3034         if (tape->chrdev_direction == idetape_direction_read)
3035                 __idetape_discard_read_pipeline(drive);
3036         idetape_wait_ready(drive, 60 * 5 * HZ);
3037         idetape_create_locate_cmd(drive, &pc, block, partition, skip);
3038         retval = idetape_queue_pc_tail(drive, &pc);
3039         if (retval)
3040                 return (retval);
3041
3042         idetape_create_read_position_cmd(&pc);
3043         return (idetape_queue_pc_tail(drive, &pc));
3044 }
3045
3046 static void idetape_discard_read_pipeline (ide_drive_t *drive, int restore_position)
3047 {
3048         idetape_tape_t *tape = drive->driver_data;
3049         int cnt;
3050         int seek, position;
3051
3052         cnt = __idetape_discard_read_pipeline(drive);
3053         if (restore_position) {
3054                 position = idetape_read_position(drive);
3055                 seek = position > cnt ? position - cnt : 0;
3056                 if (idetape_position_tape(drive, seek, 0, 0)) {
3057                         printk(KERN_INFO "ide-tape: %s: position_tape failed in discard_pipeline()\n", tape->name);
3058                         return;
3059                 }
3060         }
3061 }
3062
3063 /*
3064  * idetape_queue_rw_tail generates a read/write request for the block
3065  * device interface and wait for it to be serviced.
3066  */
3067 static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks, struct idetape_bh *bh)
3068 {
3069         idetape_tape_t *tape = drive->driver_data;
3070         struct request rq;
3071
3072 #if IDETAPE_DEBUG_LOG
3073         if (tape->debug_level >= 2)
3074                 printk(KERN_INFO "ide-tape: idetape_queue_rw_tail: cmd=%d\n",cmd);
3075 #endif /* IDETAPE_DEBUG_LOG */
3076 #if IDETAPE_DEBUG_BUGS
3077         if (idetape_pipeline_active(tape)) {
3078                 printk(KERN_ERR "ide-tape: bug: the pipeline is active in idetape_queue_rw_tail\n");
3079                 return (0);
3080         }
3081 #endif /* IDETAPE_DEBUG_BUGS */
3082
3083         idetape_init_rq(&rq, cmd);
3084         rq.rq_disk = tape->disk;
3085         rq.special = (void *)bh;
3086         rq.sector = tape->first_frame_position;
3087         rq.nr_sectors = rq.current_nr_sectors = blocks;
3088         (void) ide_do_drive_cmd(drive, &rq, ide_wait);
3089
3090         if ((cmd & (REQ_IDETAPE_READ | REQ_IDETAPE_WRITE)) == 0)
3091                 return 0;
3092
3093         if (tape->merge_stage)
3094                 idetape_init_merge_stage(tape);
3095         if (rq.errors == IDETAPE_ERROR_GENERAL)
3096                 return -EIO;
3097         return (tape->tape_block_size * (blocks-rq.current_nr_sectors));
3098 }
3099
3100 /*
3101  *      idetape_insert_pipeline_into_queue is used to start servicing the
3102  *      pipeline stages, starting from tape->next_stage.
3103  */
3104 static void idetape_insert_pipeline_into_queue (ide_drive_t *drive)
3105 {
3106         idetape_tape_t *tape = drive->driver_data;
3107
3108         if (tape->next_stage == NULL)
3109                 return;
3110         if (!idetape_pipeline_active(tape)) {
3111                 set_bit(IDETAPE_PIPELINE_ACTIVE, &tape->flags);
3112                 idetape_active_next_stage(drive);
3113                 (void) ide_do_drive_cmd(drive, tape->active_data_request, ide_end);
3114         }
3115 }
3116
3117 static void idetape_create_inquiry_cmd (idetape_pc_t *pc)
3118 {
3119         idetape_init_pc(pc);
3120         pc->c[0] = IDETAPE_INQUIRY_CMD;
3121         pc->c[4] = pc->request_transfer = 254;
3122         pc->callback = &idetape_pc_callback;
3123 }
3124
3125 static void idetape_create_rewind_cmd (ide_drive_t *drive, idetape_pc_t *pc)
3126 {
3127         idetape_init_pc(pc);
3128         pc->c[0] = IDETAPE_REWIND_CMD;
3129         set_bit(PC_WAIT_FOR_DSC, &pc->flags);
3130         pc->callback = &idetape_pc_callback;
3131 }
3132
3133 #if 0
3134 static void idetape_create_mode_select_cmd (idetape_pc_t *pc, int length)
3135 {
3136         idetape_init_pc(pc);
3137         set_bit(PC_WRITING, &pc->flags);
3138         pc->c[0] = IDETAPE_MODE_SELECT_CMD;
3139         pc->c[1] = 0x10;
3140         put_unaligned(htons(length), (unsigned short *) &pc->c[3]);
3141         pc->request_transfer = 255;
3142         pc->callback = &idetape_pc_callback;
3143 }
3144 #endif
3145
3146 static void idetape_create_erase_cmd (idetape_pc_t *pc)
3147 {
3148         idetape_init_pc(pc);
3149         pc->c[0] = IDETAPE_ERASE_CMD;
3150         pc->c[1] = 1;
3151         set_bit(PC_WAIT_FOR_DSC, &pc->flags);
3152         pc->callback = &idetape_pc_callback;
3153 }
3154
3155 static void idetape_create_space_cmd (idetape_pc_t *pc,int count, u8 cmd)
3156 {
3157         idetape_init_pc(pc);
3158         pc->c[0] = IDETAPE_SPACE_CMD;
3159         put_unaligned(htonl(count), (unsigned int *) &pc->c[1]);
3160         pc->c[1] = cmd;
3161         set_bit(PC_WAIT_FOR_DSC, &pc->flags);
3162         pc->callback = &idetape_pc_callback;
3163 }
3164
3165 static void idetape_wait_first_stage (ide_drive_t *drive)
3166 {
3167         idetape_tape_t *tape = drive->driver_data;
3168         unsigned long flags;
3169
3170         if (tape->first_stage == NULL)
3171                 return;
3172         spin_lock_irqsave(&tape->spinlock, flags);
3173         if (tape->active_stage == tape->first_stage)
3174                 idetape_wait_for_request(drive, tape->active_data_request);
3175         spin_unlock_irqrestore(&tape->spinlock, flags);
3176 }
3177
3178 /*
3179  *      idetape_add_chrdev_write_request tries to add a character device
3180  *      originated write request to our pipeline. In case we don't succeed,
3181  *      we revert to non-pipelined operation mode for this request.
3182  *
3183  *      1.      Try to allocate a new pipeline stage.
3184  *      2.      If we can't, wait for more and more requests to be serviced
3185  *              and try again each time.
3186  *      3.      If we still can't allocate a stage, fallback to
3187  *              non-pipelined operation mode for this request.
3188  */
3189 static int idetape_add_chrdev_write_request (ide_drive_t *drive, int blocks)
3190 {
3191         idetape_tape_t *tape = drive->driver_data;
3192         idetape_stage_t *new_stage;
3193         unsigned long flags;
3194         struct request *rq;
3195
3196 #if IDETAPE_DEBUG_LOG
3197         if (tape->debug_level >= 3)
3198                 printk(KERN_INFO "ide-tape: Reached idetape_add_chrdev_write_request\n");
3199 #endif /* IDETAPE_DEBUG_LOG */
3200
3201         /*
3202          *      Attempt to allocate a new stage.
3203          *      Pay special attention to possible race conditions.
3204          */
3205         while ((new_stage = idetape_kmalloc_stage(tape)) == NULL) {
3206                 spin_lock_irqsave(&tape->spinlock, flags);
3207                 if (idetape_pipeline_active(tape)) {
3208                         idetape_wait_for_request(drive, tape->active_data_request);
3209                         spin_unlock_irqrestore(&tape->spinlock, flags);
3210                 } else {
3211                         spin_unlock_irqrestore(&tape->spinlock, flags);
3212                         idetape_insert_pipeline_into_queue(drive);
3213                         if (idetape_pipeline_active(tape))
3214                                 continue;
3215                         /*
3216                          *      Linux is short on memory. Fallback to
3217                          *      non-pipelined operation mode for this request.
3218                          */
3219                         return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks, tape->merge_stage->bh);
3220                 }
3221         }
3222         rq = &new_stage->rq;
3223         idetape_init_rq(rq, REQ_IDETAPE_WRITE);
3224         /* Doesn't actually matter - We always assume sequential access */
3225         rq->sector = tape->first_frame_position;
3226         rq->nr_sectors = rq->current_nr_sectors = blocks;
3227
3228         idetape_switch_buffers(tape, new_stage);
3229         idetape_add_stage_tail(drive, new_stage);
3230         tape->pipeline_head++;
3231         calculate_speeds(drive);
3232
3233         /*
3234          *      Estimate whether the tape has stopped writing by checking
3235          *      if our write pipeline is currently empty. If we are not
3236          *      writing anymore, wait for the pipeline to be full enough
3237          *      (90%) before starting to service requests, so that we will
3238          *      be able to keep up with the higher speeds of the tape.
3239          */
3240         if (!idetape_pipeline_active(tape)) {
3241                 if (tape->nr_stages >= tape->max_stages * 9 / 10 ||
3242                     tape->nr_stages >= tape->max_stages - tape->uncontrolled_pipeline_head_speed * 3 * 1024 / tape->tape_block_size) {
3243                         tape->measure_insert_time = 1;
3244                         tape->insert_time = jiffies;
3245                         tape->insert_size = 0;
3246                         tape->insert_speed = 0;
3247                         idetape_insert_pipeline_into_queue(drive);
3248                 }
3249         }
3250         if (test_and_clear_bit(IDETAPE_PIPELINE_ERROR, &tape->flags))
3251                 /* Return a deferred error */
3252                 return -EIO;
3253         return blocks;
3254 }
3255
3256 /*
3257  *      idetape_wait_for_pipeline will wait until all pending pipeline
3258  *      requests are serviced. Typically called on device close.
3259  */
3260 static void idetape_wait_for_pipeline (ide_drive_t *drive)
3261 {
3262         idetape_tape_t *tape = drive->driver_data;
3263         unsigned long flags;
3264
3265         while (tape->next_stage || idetape_pipeline_active(tape)) {
3266                 idetape_insert_pipeline_into_queue(drive);
3267                 spin_lock_irqsave(&tape->spinlock, flags);
3268                 if (idetape_pipeline_active(tape))
3269                         idetape_wait_for_request(drive, tape->active_data_request);
3270                 spin_unlock_irqrestore(&tape->spinlock, flags);
3271         }
3272 }
3273
3274 static void idetape_empty_write_pipeline (ide_drive_t *drive)
3275 {
3276         idetape_tape_t *tape = drive->driver_data;
3277         int blocks, min;
3278         struct idetape_bh *bh;
3279
3280 #if IDETAPE_DEBUG_BUGS
3281         if (tape->chrdev_direction != idetape_direction_write) {
3282                 printk(KERN_ERR "ide-tape: bug: Trying to empty write pipeline, but we are not writing.\n");
3283                 return;
3284         }
3285         if (tape->merge_stage_size > tape->stage_size) {
3286                 printk(KERN_ERR "ide-tape: bug: merge_buffer too big\n");
3287                 tape->merge_stage_size = tape->stage_size;
3288         }
3289 #endif /* IDETAPE_DEBUG_BUGS */
3290         if (tape->merge_stage_size) {
3291                 blocks = tape->merge_stage_size / tape->tape_block_size;
3292                 if (tape->merge_stage_size % tape->tape_block_size) {
3293                         unsigned int i;
3294
3295                         blocks++;
3296                         i = tape->tape_block_size - tape->merge_stage_size % tape->tape_block_size;
3297                         bh = tape->bh->b_reqnext;
3298                         while (bh) {
3299                                 atomic_set(&bh->b_count, 0);
3300                                 bh = bh->b_reqnext;
3301                         }
3302                         bh = tape->bh;
3303                         while (i) {
3304                                 if (bh == NULL) {
3305
3306                                         printk(KERN_INFO "ide-tape: bug, bh NULL\n");
3307                                         break;
3308                                 }
3309                                 min = min(i, (unsigned int)(bh->b_size - atomic_read(&bh->b_count)));
3310                                 memset(bh->b_data + atomic_read(&bh->b_count), 0, min);
3311                                 atomic_add(min, &bh->b_count);
3312                                 i -= min;
3313                                 bh = bh->b_reqnext;
3314                         }
3315                 }
3316                 (void) idetape_add_chrdev_write_request(drive, blocks);
3317                 tape->merge_stage_size = 0;
3318         }
3319         idetape_wait_for_pipeline(drive);
3320         if (tape->merge_stage != NULL) {
3321                 __idetape_kfree_stage(tape->merge_stage);
3322                 tape->merge_stage = NULL;
3323         }
3324         clear_bit(IDETAPE_PIPELINE_ERROR, &tape->flags);
3325         tape->chrdev_direction = idetape_direction_none;
3326
3327         /*
3328          *      On the next backup, perform the feedback loop again.
3329          *      (I don't want to keep sense information between backups,
3330          *       as some systems are constantly on, and the system load
3331          *       can be totally different on the next backup).
3332          */
3333         tape->max_stages = tape->min_pipeline;
3334 #if IDETAPE_DEBUG_BUGS
3335         if (tape->first_stage != NULL ||
3336             tape->next_stage != NULL ||
3337             tape->last_stage != NULL ||
3338             tape->nr_stages != 0) {
3339                 printk(KERN_ERR "ide-tape: ide-tape pipeline bug, "
3340                         "first_stage %p, next_stage %p, "
3341                         "last_stage %p, nr_stages %d\n",
3342                         tape->first_stage, tape->next_stage,
3343                         tape->last_stage, tape->nr_stages);
3344         }
3345 #endif /* IDETAPE_DEBUG_BUGS */
3346 }
3347
3348 static void idetape_restart_speed_control (ide_drive_t *drive)
3349 {
3350         idetape_tape_t *tape = drive->driver_data;
3351
3352         tape->restart_speed_control_req = 0;
3353         tape->pipeline_head = 0;
3354         tape->controlled_last_pipeline_head = tape->uncontrolled_last_pipeline_head = 0;
3355         tape->controlled_previous_pipeline_head = tape->uncontrolled_previous_pipeline_head = 0;
3356         tape->pipeline_head_speed = tape->controlled_pipeline_head_speed = 5000;
3357         tape->uncontrolled_pipeline_head_speed = 0;
3358         tape->controlled_pipeline_head_time = tape->uncontrolled_pipeline_head_time = jiffies;
3359         tape->controlled_previous_head_time = tape->uncontrolled_previous_head_time = jiffies;
3360 }
3361
3362 static int idetape_initiate_read (ide_drive_t *drive, int max_stages)
3363 {
3364         idetape_tape_t *tape = drive->driver_data;
3365         idetape_stage_t *new_stage;
3366         struct request rq;
3367         int bytes_read;
3368         int blocks = tape->capabilities.ctl;
3369
3370         /* Initialize read operation */
3371         if (tape->chrdev_direction != idetape_direction_read) {
3372                 if (tape->chrdev_direction == idetape_direction_write) {
3373                         idetape_empty_write_pipeline(drive);
3374                         idetape_flush_tape_buffers(drive);
3375                 }
3376 #if IDETAPE_DEBUG_BUGS
3377                 if (tape->merge_stage || tape->merge_stage_size) {
3378                         printk (KERN_ERR "ide-tape: merge_stage_size should be 0 now\n");
3379                         tape->merge_stage_size = 0;
3380                 }
3381 #endif /* IDETAPE_DEBUG_BUGS */
3382                 if ((tape->merge_stage = __idetape_kmalloc_stage(tape, 0, 0)) == NULL)
3383                         return -ENOMEM;
3384                 tape->chrdev_direction = idetape_direction_read;
3385
3386                 /*
3387                  *      Issue a read 0 command to ensure that DSC handshake
3388                  *      is switched from completion mode to buffer available
3389                  *      mode.
3390                  *      No point in issuing this if DSC overlap isn't supported,
3391                  *      some drives (Seagate STT3401A) will return an error.
3392                  */
3393                 if (drive->dsc_overlap) {
3394                         bytes_read = idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, 0, tape->merge_stage->bh);
3395                         if (bytes_read < 0) {
3396                                 __idetape_kfree_stage(tape->merge_stage);
3397                                 tape->merge_stage = NULL;
3398                                 tape->chrdev_direction = idetape_direction_none;
3399                                 return bytes_read;
3400                         }
3401                 }
3402         }
3403         if (tape->restart_speed_control_req)
3404                 idetape_restart_speed_control(drive);
3405         idetape_init_rq(&rq, REQ_IDETAPE_READ);
3406         rq.sector = tape->first_frame_position;
3407         rq.nr_sectors = rq.current_nr_sectors = blocks;
3408         if (!test_bit(IDETAPE_PIPELINE_ERROR, &tape->flags) &&
3409             tape->nr_stages < max_stages) {
3410                 new_stage = idetape_kmalloc_stage(tape);
3411                 while (new_stage != NULL) {
3412                         new_stage->rq = rq;
3413                         idetape_add_stage_tail(drive, new_stage);
3414                         if (tape->nr_stages >= max_stages)
3415                                 break;
3416                         new_stage = idetape_kmalloc_stage(tape);
3417                 }
3418         }
3419         if (!idetape_pipeline_active(tape)) {
3420                 if (tape->nr_pending_stages >= 3 * max_stages / 4) {
3421                         tape->measure_insert_time = 1;
3422                         tape->insert_time = jiffies;
3423                         tape->insert_size = 0;
3424                         tape->insert_speed = 0;
3425                         idetape_insert_pipeline_into_queue(drive);
3426                 }
3427         }
3428         return 0;
3429 }
3430
3431 /*
3432  *      idetape_add_chrdev_read_request is called from idetape_chrdev_read
3433  *      to service a character device read request and add read-ahead
3434  *      requests to our pipeline.
3435  */
3436 static int idetape_add_chrdev_read_request (ide_drive_t *drive,int blocks)
3437 {
3438         idetape_tape_t *tape = drive->driver_data;
3439         unsigned long flags;
3440         struct request *rq_ptr;
3441         int bytes_read;
3442
3443 #if IDETAPE_DEBUG_LOG
3444         if (tape->debug_level >= 4)
3445                 printk(KERN_INFO "ide-tape: Reached idetape_add_chrdev_read_request, %d blocks\n", blocks);
3446 #endif /* IDETAPE_DEBUG_LOG */
3447
3448         /*
3449          * If we are at a filemark, return a read length of 0
3450          */
3451         if (test_bit(IDETAPE_FILEMARK, &tape->flags))
3452                 return 0;
3453
3454         /*
3455          * Wait for the next block to be available at the head
3456          * of the pipeline
3457          */
3458         idetape_initiate_read(drive, tape->max_stages);
3459         if (tape->first_stage == NULL) {
3460                 if (test_bit(IDETAPE_PIPELINE_ERROR, &tape->flags))
3461                         return 0;
3462                 return idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, blocks, tape->merge_stage->bh);
3463         }
3464         idetape_wait_first_stage(drive);
3465         rq_ptr = &tape->first_stage->rq;
3466         bytes_read = tape->tape_block_size * (rq_ptr->nr_sectors - rq_ptr->current_nr_sectors);
3467         rq_ptr->nr_sectors = rq_ptr->current_nr_sectors = 0;
3468
3469
3470         if (rq_ptr->errors == IDETAPE_ERROR_EOD)
3471                 return 0;
3472         else {
3473                 idetape_switch_buffers(tape, tape->first_stage);
3474                 if (rq_ptr->errors == IDETAPE_ERROR_FILEMARK)
3475                         set_bit(IDETAPE_FILEMARK, &tape->flags);
3476                 spin_lock_irqsave(&tape->spinlock, flags);
3477                 idetape_remove_stage_head(drive);
3478                 spin_unlock_irqrestore(&tape->spinlock, flags);
3479                 tape->pipeline_head++;
3480                 calculate_speeds(drive);
3481         }
3482 #if IDETAPE_DEBUG_BUGS
3483         if (bytes_read > blocks * tape->tape_block_size) {
3484                 printk(KERN_ERR "ide-tape: bug: trying to return more bytes than requested\n");
3485                 bytes_read = blocks * tape->tape_block_size;
3486         }
3487 #endif /* IDETAPE_DEBUG_BUGS */
3488         return (bytes_read);
3489 }
3490
3491 static void idetape_pad_zeros (ide_drive_t *drive, int bcount)
3492 {
3493         idetape_tape_t *tape = drive->driver_data;
3494         struct idetape_bh *bh;
3495         int blocks;
3496
3497         while (bcount) {
3498                 unsigned int count;
3499
3500                 bh = tape->merge_stage->bh;
3501                 count = min(tape->stage_size, bcount);
3502                 bcount -= count;
3503                 blocks = count / tape->tape_block_size;
3504                 while (count) {
3505                         atomic_set(&bh->b_count, min(count, (unsigned int)bh->b_size));
3506                         memset(bh->b_data, 0, atomic_read(&bh->b_count));
3507                         count -= atomic_read(&bh->b_count);
3508                         bh = bh->b_reqnext;
3509                 }
3510                 idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks, tape->merge_stage->bh);
3511         }
3512 }
3513
3514 static int idetape_pipeline_size (ide_drive_t *drive)
3515 {
3516         idetape_tape_t *tape = drive->driver_data;
3517         idetape_stage_t *stage;
3518         struct request *rq;
3519         int size = 0;
3520
3521         idetape_wait_for_pipeline(drive);
3522         stage = tape->first_stage;
3523         while (stage != NULL) {
3524                 rq = &stage->rq;
3525                 size += tape->tape_block_size * (rq->nr_sectors-rq->current_nr_sectors);
3526                 if (rq->errors == IDETAPE_ERROR_FILEMARK)
3527                         size += tape->tape_block_size;
3528                 stage = stage->next;
3529         }
3530         size += tape->merge_stage_size;
3531         return size;
3532 }
3533
3534 /*
3535  *      Rewinds the tape to the Beginning Of the current Partition (BOP).
3536  *
3537  *      We currently support only one partition.
3538  */
3539 static int idetape_rewind_tape (ide_drive_t *drive)
3540 {
3541         int retval;
3542         idetape_pc_t pc;
3543 #if IDETAPE_DEBUG_LOG
3544         idetape_tape_t *tape = drive->driver_data;
3545         if (tape->debug_level >= 2)
3546                 printk(KERN_INFO "ide-tape: Reached idetape_rewind_tape\n");
3547 #endif /* IDETAPE_DEBUG_LOG */
3548
3549         idetape_create_rewind_cmd(drive, &pc);
3550         retval = idetape_queue_pc_tail(drive, &pc);
3551         if (retval)
3552                 return retval;
3553
3554         idetape_create_read_position_cmd(&pc);
3555         retval = idetape_queue_pc_tail(drive, &pc);
3556         if (retval)
3557                 return retval;
3558         return 0;
3559 }
3560
3561 /*
3562  *      Our special ide-tape ioctl's.
3563  *
3564  *      Currently there aren't any ioctl's.
3565  *      mtio.h compatible commands should be issued to the character device
3566  *      interface.
3567  */
3568 static int idetape_blkdev_ioctl(ide_drive_t *drive, unsigned int cmd, unsigned long arg)
3569 {
3570         idetape_tape_t *tape = drive->driver_data;
3571         idetape_config_t config;
3572         void __user *argp = (void __user *)arg;
3573
3574 #if IDETAPE_DEBUG_LOG
3575         if (tape->debug_level >= 4)
3576                 printk(KERN_INFO "ide-tape: Reached idetape_blkdev_ioctl\n");
3577 #endif /* IDETAPE_DEBUG_LOG */
3578         switch (cmd) {
3579                 case 0x0340:
3580                         if (copy_from_user(&config, argp, sizeof (idetape_config_t)))
3581                                 return -EFAULT;
3582                         tape->best_dsc_rw_frequency = config.dsc_rw_frequency;
3583                         tape->max_stages = config.nr_stages;
3584                         break;
3585                 case 0x0350:
3586                         config.dsc_rw_frequency = (int) tape->best_dsc_rw_frequency;
3587                         config.nr_stages = tape->max_stages;
3588                         if (copy_to_user(argp, &config, sizeof (idetape_config_t)))
3589                                 return -EFAULT;
3590                         break;
3591                 default:
3592                         return -EIO;
3593         }
3594         return 0;
3595 }
3596
3597 /*
3598  *      idetape_space_over_filemarks is now a bit more complicated than just
3599  *      passing the command to the tape since we may have crossed some
3600  *      filemarks during our pipelined read-ahead mode.
3601  *
3602  *      As a minor side effect, the pipeline enables us to support MTFSFM when
3603  *      the filemark is in our internal pipeline even if the tape doesn't
3604  *      support spacing over filemarks in the reverse direction.
3605  */
3606 static int idetape_space_over_filemarks (ide_drive_t *drive,short mt_op,int mt_count)
3607 {
3608         idetape_tape_t *tape = drive->driver_data;
3609         idetape_pc_t pc;
3610         unsigned long flags;
3611         int retval,count=0;
3612
3613         if (mt_count == 0)
3614                 return 0;
3615         if (MTBSF == mt_op || MTBSFM == mt_op) {
3616                 if (!tape->capabilities.sprev)
3617                         return -EIO;
3618                 mt_count = - mt_count;
3619         }
3620
3621         if (tape->chrdev_direction == idetape_direction_read) {
3622                 /*
3623                  *      We have a read-ahead buffer. Scan it for crossed
3624                  *      filemarks.
3625                  */
3626                 tape->merge_stage_size = 0;
3627                 if (test_and_clear_bit(IDETAPE_FILEMARK, &tape->flags))
3628                         ++count;
3629                 while (tape->first_stage != NULL) {
3630                         if (count == mt_count) {
3631                                 if (mt_op == MTFSFM)
3632                                         set_bit(IDETAPE_FILEMARK, &tape->flags);
3633                                 return 0;
3634                         }
3635                         spin_lock_irqsave(&tape->spinlock, flags);
3636                         if (tape->first_stage == tape->active_stage) {
3637                                 /*
3638                                  *      We have reached the active stage in the read pipeline.
3639                                  *      There is no point in allowing the drive to continue
3640                                  *      reading any farther, so we stop the pipeline.
3641                                  *
3642                                  *      This section should be moved to a separate subroutine,
3643                                  *      because a similar function is performed in
3644                                  *      __idetape_discard_read_pipeline(), for example.
3645                                  */
3646                                 tape->next_stage = NULL;
3647                                 spin_unlock_irqrestore(&tape->spinlock, flags);
3648                                 idetape_wait_first_stage(drive);
3649                                 tape->next_stage = tape->first_stage->next;
3650                         } else
3651                                 spin_unlock_irqrestore(&tape->spinlock, flags);
3652                         if (tape->first_stage->rq.errors == IDETAPE_ERROR_FILEMARK)
3653                                 ++count;
3654                         idetape_remove_stage_head(drive);
3655                 }
3656                 idetape_discard_read_pipeline(drive, 0);
3657         }
3658
3659         /*
3660          *      The filemark was not found in our internal pipeline.
3661          *      Now we can issue the space command.
3662          */
3663         switch (mt_op) {
3664                 case MTFSF:
3665                 case MTBSF:
3666                         idetape_create_space_cmd(&pc,mt_count-count,IDETAPE_SPACE_OVER_FILEMARK);
3667                         return (idetape_queue_pc_tail(drive, &pc));
3668                 case MTFSFM:
3669                 case MTBSFM:
3670                         if (!tape->capabilities.sprev)
3671                                 return (-EIO);
3672                         retval = idetape_space_over_filemarks(drive, MTFSF, mt_count-count);
3673                         if (retval) return (retval);
3674                         count = (MTBSFM == mt_op ? 1 : -1);
3675                         return (idetape_space_over_filemarks(drive, MTFSF, count));
3676                 default:
3677                         printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",mt_op);
3678                         return (-EIO);
3679         }
3680 }
3681
3682
3683 /*
3684  *      Our character device read / write functions.
3685  *
3686  *      The tape is optimized to maximize throughput when it is transferring
3687  *      an integral number of the "continuous transfer limit", which is
3688  *      a parameter of the specific tape (26 KB on my particular tape).
3689  *      (32 kB for Onstream)
3690  *
3691  *      As of version 1.3 of the driver, the character device provides an
3692  *      abstract continuous view of the media - any mix of block sizes (even 1
3693  *      byte) on the same backup/restore procedure is supported. The driver
3694  *      will internally convert the requests to the recommended transfer unit,
3695  *      so that an unmatch between the user's block size to the recommended
3696  *      size will only result in a (slightly) increased driver overhead, but
3697  *      will no longer hit performance.
3698  *      This is not applicable to Onstream.
3699  */
3700 static ssize_t idetape_chrdev_read (struct file *file, char __user *buf,
3701                                     size_t count, loff_t *ppos)
3702 {
3703         struct ide_tape_obj *tape = ide_tape_f(file);
3704         ide_drive_t *drive = tape->drive;
3705         ssize_t bytes_read,temp, actually_read = 0, rc;
3706         ssize_t ret = 0;
3707
3708 #if IDETAPE_DEBUG_LOG
3709         if (tape->debug_level >= 3)
3710                 printk(KERN_INFO "ide-tape: Reached idetape_chrdev_read, count %Zd\n", count);
3711 #endif /* IDETAPE_DEBUG_LOG */
3712
3713         if (tape->chrdev_direction != idetape_direction_read) {
3714                 if (test_bit(IDETAPE_DETECT_BS, &tape->flags))
3715                         if (count > tape->tape_block_size &&
3716                             (count % tape->tape_block_size) == 0)
3717                                 tape->user_bs_factor = count / tape->tape_block_size;
3718         }
3719         if ((rc = idetape_initiate_read(drive, tape->max_stages)) < 0)
3720                 return rc;
3721         if (count == 0)
3722                 return (0);
3723         if (tape->merge_stage_size) {
3724                 actually_read = min((unsigned int)(tape->merge_stage_size), (unsigned int)count);
3725                 if (idetape_copy_stage_to_user(tape, buf, tape->merge_stage, actually_read))
3726                         ret = -EFAULT;
3727                 buf += actually_read;
3728                 tape->merge_stage_size -= actually_read;
3729                 count -= actually_read;
3730         }
3731         while (count >= tape->stage_size) {
3732                 bytes_read = idetape_add_chrdev_read_request(drive, tape->capabilities.ctl);
3733                 if (bytes_read <= 0)
3734                         goto finish;
3735                 if (idetape_copy_stage_to_user(tape, buf, tape->merge_stage, bytes_read))
3736                         ret = -EFAULT;
3737                 buf += bytes_read;
3738                 count -= bytes_read;
3739                 actually_read += bytes_read;
3740         }
3741         if (count) {
3742                 bytes_read = idetape_add_chrdev_read_request(drive, tape->capabilities.ctl);
3743                 if (bytes_read <= 0)
3744                         goto finish;
3745                 temp = min((unsigned long)count, (unsigned long)bytes_read);
3746                 if (idetape_copy_stage_to_user(tape, buf, tape->merge_stage, temp))
3747                         ret = -EFAULT;
3748                 actually_read += temp;
3749                 tape->merge_stage_size = bytes_read-temp;
3750         }
3751 finish:
3752         if (!actually_read && test_bit(IDETAPE_FILEMARK, &tape->flags)) {
3753 #if IDETAPE_DEBUG_LOG
3754                 if (tape->debug_level >= 2)
3755                         printk(KERN_INFO "ide-tape: %s: spacing over filemark\n", tape->name);
3756 #endif
3757                 idetape_space_over_filemarks(drive, MTFSF, 1);
3758                 return 0;
3759         }
3760
3761         return (ret) ? ret : actually_read;
3762 }
3763
3764 static ssize_t idetape_chrdev_write (struct file *file, const char __user *buf,
3765                                      size_t count, loff_t *ppos)
3766 {
3767         struct ide_tape_obj *tape = ide_tape_f(file);
3768         ide_drive_t *drive = tape->drive;
3769         ssize_t actually_written = 0;
3770         ssize_t ret = 0;
3771
3772         /* The drive is write protected. */
3773         if (tape->write_prot)
3774                 return -EACCES;
3775
3776 #if IDETAPE_DEBUG_LOG
3777         if (tape->debug_level >= 3)
3778                 printk(KERN_INFO "ide-tape: Reached idetape_chrdev_write, "
3779                         "count %Zd\n", count);
3780 #endif /* IDETAPE_DEBUG_LOG */
3781
3782         /* Initialize write operation */
3783         if (tape->chrdev_direction != idetape_direction_write) {
3784                 if (tape->chrdev_direction == idetape_direction_read)
3785                         idetape_discard_read_pipeline(drive, 1);
3786 #if IDETAPE_DEBUG_BUGS
3787                 if (tape->merge_stage || tape->merge_stage_size) {
3788                         printk(KERN_ERR "ide-tape: merge_stage_size "
3789                                 "should be 0 now\n");
3790                         tape->merge_stage_size = 0;
3791                 }
3792 #endif /* IDETAPE_DEBUG_BUGS */
3793                 if ((tape->merge_stage = __idetape_kmalloc_stage(tape, 0, 0)) == NULL)
3794                         return -ENOMEM;
3795                 tape->chrdev_direction = idetape_direction_write;
3796                 idetape_init_merge_stage(tape);
3797
3798                 /*
3799                  *      Issue a write 0 command to ensure that DSC handshake
3800                  *      is switched from completion mode to buffer available
3801                  *      mode.
3802                  *      No point in issuing this if DSC overlap isn't supported,
3803                  *      some drives (Seagate STT3401A) will return an error.
3804                  */
3805                 if (drive->dsc_overlap) {
3806                         ssize_t retval = idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, 0, tape->merge_stage->bh);
3807                         if (retval < 0) {
3808                                 __idetape_kfree_stage(tape->merge_stage);
3809                                 tape->merge_stage = NULL;
3810                                 tape->chrdev_direction = idetape_direction_none;
3811                                 return retval;
3812                         }
3813                 }
3814         }
3815         if (count == 0)
3816                 return (0);
3817         if (tape->restart_speed_control_req)
3818                 idetape_restart_speed_control(drive);
3819         if (tape->merge_stage_size) {
3820 #if IDETAPE_DEBUG_BUGS
3821                 if (tape->merge_stage_size >= tape->stage_size) {
3822                         printk(KERN_ERR "ide-tape: bug: merge buffer too big\n");
3823                         tape->merge_stage_size = 0;
3824                 }
3825 #endif /* IDETAPE_DEBUG_BUGS */
3826                 actually_written = min((unsigned int)(tape->stage_size - tape->merge_stage_size), (unsigned int)count);
3827                 if (idetape_copy_stage_from_user(tape, tape->merge_stage, buf, actually_written))
3828                                 ret = -EFAULT;
3829                 buf += actually_written;
3830                 tape->merge_stage_size += actually_written;
3831                 count -= actually_written;
3832
3833                 if (tape->merge_stage_size == tape->stage_size) {
3834                         ssize_t retval;
3835                         tape->merge_stage_size = 0;
3836                         retval = idetape_add_chrdev_write_request(drive, tape->capabilities.ctl);
3837                         if (retval <= 0)
3838                                 return (retval);
3839                 }
3840         }
3841         while (count >= tape->stage_size) {
3842                 ssize_t retval;
3843                 if (idetape_copy_stage_from_user(tape, tape->merge_stage, buf, tape->stage_size))
3844                         ret = -EFAULT;
3845                 buf += tape->stage_size;
3846                 count -= tape->stage_size;
3847                 retval = idetape_add_chrdev_write_request(drive, tape->capabilities.ctl);
3848                 actually_written += tape->stage_size;
3849                 if (retval <= 0)
3850                         return (retval);
3851         }
3852         if (count) {
3853                 actually_written += count;
3854                 if (idetape_copy_stage_from_user(tape, tape->merge_stage, buf, count))
3855                         ret = -EFAULT;
3856                 tape->merge_stage_size += count;
3857         }
3858         return (ret) ? ret : actually_written;
3859 }
3860
3861 static int idetape_write_filemark (ide_drive_t *drive)
3862 {
3863         idetape_pc_t pc;
3864
3865         /* Write a filemark */
3866         idetape_create_write_filemark_cmd(drive, &pc, 1);
3867         if (idetape_queue_pc_tail(drive, &pc)) {
3868                 printk(KERN_ERR "ide-tape: Couldn't write a filemark\n");
3869                 return -EIO;
3870         }
3871         return 0;
3872 }
3873
3874 /*
3875  *      idetape_mtioctop is called from idetape_chrdev_ioctl when
3876  *      the general mtio MTIOCTOP ioctl is requested.
3877  *
3878  *      We currently support the following mtio.h operations:
3879  *
3880  *      MTFSF   -       Space over mt_count filemarks in the positive direction.
3881  *                      The tape is positioned after the last spaced filemark.
3882  *
3883  *      MTFSFM  -       Same as MTFSF, but the tape is positioned before the
3884  *                      last filemark.
3885  *
3886  *      MTBSF   -       Steps background over mt_count filemarks, tape is
3887  *                      positioned before the last filemark.
3888  *
3889  *      MTBSFM  -       Like MTBSF, only tape is positioned after the last filemark.
3890  *
3891  *      Note:
3892  *
3893  *              MTBSF and MTBSFM are not supported when the tape doesn't
3894  *              support spacing over filemarks in the reverse direction.
3895  *              In this case, MTFSFM is also usually not supported (it is
3896  *              supported in the rare case in which we crossed the filemark
3897  *              during our read-ahead pipelined operation mode).
3898  *
3899  *      MTWEOF  -       Writes mt_count filemarks. Tape is positioned after
3900  *                      the last written filemark.
3901  *
3902  *      MTREW   -       Rewinds tape.
3903  *
3904  *      MTLOAD  -       Loads the tape.
3905  *
3906  *      MTOFFL  -       Puts the tape drive "Offline": Rewinds the tape and
3907  *      MTUNLOAD        prevents further access until the media is replaced.
3908  *
3909  *      MTNOP   -       Flushes tape buffers.
3910  *
3911  *      MTRETEN -       Retension media. This typically consists of one end
3912  *                      to end pass on the media.
3913  *
3914  *      MTEOM   -       Moves to the end of recorded data.
3915  *
3916  *      MTERASE -       Erases tape.
3917  *
3918  *      MTSETBLK -      Sets the user block size to mt_count bytes. If
3919  *                      mt_count is 0, we will attempt to autodetect
3920  *                      the block size.
3921  *
3922  *      MTSEEK  -       Positions the tape in a specific block number, where
3923  *                      each block is assumed to contain which user_block_size
3924  *                      bytes.
3925  *
3926  *      MTSETPART -     Switches to another tape partition.
3927  *
3928  *      MTLOCK -        Locks the tape door.
3929  *
3930  *      MTUNLOCK -      Unlocks the tape door.
3931  *
3932  *      The following commands are currently not supported:
3933  *
3934  *      MTFSS, MTBSS, MTWSM, MTSETDENSITY,
3935  *      MTSETDRVBUFFER, MT_ST_BOOLEANS, MT_ST_WRITE_THRESHOLD.
3936  */
3937 static int idetape_mtioctop (ide_drive_t *drive,short mt_op,int mt_count)
3938 {
3939         idetape_tape_t *tape = drive->driver_data;
3940         idetape_pc_t pc;
3941         int i,retval;
3942
3943 #if IDETAPE_DEBUG_LOG
3944         if (tape->debug_level >= 1)
3945                 printk(KERN_INFO "ide-tape: Handling MTIOCTOP ioctl: "
3946                         "mt_op=%d, mt_count=%d\n", mt_op, mt_count);
3947 #endif /* IDETAPE_DEBUG_LOG */
3948         /*
3949          *      Commands which need our pipelined read-ahead stages.
3950          */
3951         switch (mt_op) {
3952                 case MTFSF:
3953                 case MTFSFM:
3954                 case MTBSF:
3955                 case MTBSFM:
3956                         if (!mt_count)
3957                                 return (0);
3958                         return (idetape_space_over_filemarks(drive,mt_op,mt_count));
3959                 default:
3960                         break;
3961         }
3962         switch (mt_op) {
3963                 case MTWEOF:
3964                         if (tape->write_prot)
3965                                 return -EACCES;
3966                         idetape_discard_read_pipeline(drive, 1);
3967                         for (i = 0; i < mt_count; i++) {
3968                                 retval = idetape_write_filemark(drive);
3969                                 if (retval)
3970                                         return retval;
3971                         }
3972                         return (0);
3973                 case MTREW:
3974                         idetape_discard_read_pipeline(drive, 0);
3975                         if (idetape_rewind_tape(drive))
3976                                 return -EIO;
3977                         return 0;
3978                 case MTLOAD:
3979                         idetape_discard_read_pipeline(drive, 0);
3980                         idetape_create_load_unload_cmd(drive, &pc, IDETAPE_LU_LOAD_MASK);
3981                         return (idetape_queue_pc_tail(drive, &pc));
3982                 case MTUNLOAD:
3983                 case MTOFFL:
3984                         /*
3985                          * If door is locked, attempt to unlock before
3986                          * attempting to eject.
3987                          */
3988                         if (tape->door_locked) {
3989                                 if (idetape_create_prevent_cmd(drive, &pc, 0))
3990                                         if (!idetape_queue_pc_tail(drive, &pc))
3991                                                 tape->door_locked = DOOR_UNLOCKED;
3992                         }
3993                         idetape_discard_read_pipeline(drive, 0);
3994                         idetape_create_load_unload_cmd(drive, &pc,!IDETAPE_LU_LOAD_MASK);
3995                         retval = idetape_queue_pc_tail(drive, &pc);
3996                         if (!retval)
3997                                 clear_bit(IDETAPE_MEDIUM_PRESENT, &tape->flags);
3998                         return retval;
3999                 case MTNOP:
4000                         idetape_discard_read_pipeline(drive, 0);
4001                         return (idetape_flush_tape_buffers(drive));
4002                 case MTRETEN:
4003                         idetape_discard_read_pipeline(drive, 0);
4004                         idetape_create_load_unload_cmd(drive, &pc,IDETAPE_LU_RETENSION_MASK | IDETAPE_LU_LOAD_MASK);
4005                         return (idetape_queue_pc_tail(drive, &pc));
4006                 case MTEOM:
4007                         idetape_create_space_cmd(&pc, 0, IDETAPE_SPACE_TO_EOD);
4008                         return (idetape_queue_pc_tail(drive, &pc));
4009                 case MTERASE:
4010                         (void) idetape_rewind_tape(drive);
4011                         idetape_create_erase_cmd(&pc);
4012                         return (idetape_queue_pc_tail(drive, &pc));
4013                 case MTSETBLK:
4014                         if (mt_count) {
4015                                 if (mt_count < tape->tape_block_size || mt_count % tape->tape_block_size)
4016                                         return -EIO;
4017                                 tape->user_bs_factor = mt_count / tape->tape_block_size;
4018                                 clear_bit(IDETAPE_DETECT_BS, &tape->flags);
4019                         } else
4020                                 set_bit(IDETAPE_DETECT_BS, &tape->flags);
4021                         return 0;
4022                 case MTSEEK:
4023                         idetape_discard_read_pipeline(drive, 0);
4024                         return idetape_position_tape(drive, mt_count * tape->user_bs_factor, tape->partition, 0);
4025                 case MTSETPART:
4026                         idetape_discard_read_pipeline(drive, 0);
4027                         return (idetape_position_tape(drive, 0, mt_count, 0));
4028                 case MTFSR:
4029                 case MTBSR:
4030                 case MTLOCK:
4031                         if (!idetape_create_prevent_cmd(drive, &pc, 1))
4032                                 return 0;
4033                         retval = idetape_queue_pc_tail(drive, &pc);
4034                         if (retval) return retval;
4035                         tape->door_locked = DOOR_EXPLICITLY_LOCKED;
4036                         return 0;
4037                 case MTUNLOCK:
4038                         if (!idetape_create_prevent_cmd(drive, &pc, 0))
4039                                 return 0;
4040                         retval = idetape_queue_pc_tail(drive, &pc);
4041                         if (retval) return retval;
4042                         tape->door_locked = DOOR_UNLOCKED;
4043                         return 0;
4044                 default:
4045                         printk(KERN_ERR "ide-tape: MTIO operation %d not "
4046                                 "supported\n", mt_op);
4047                         return (-EIO);
4048         }
4049 }
4050
4051 /*
4052  *      Our character device ioctls.
4053  *
4054  *      General mtio.h magnetic io commands are supported here, and not in
4055  *      the corresponding block interface.
4056  *
4057  *      The following ioctls are supported:
4058  *
4059  *      MTIOCTOP -      Refer to idetape_mtioctop for detailed description.
4060  *
4061  *      MTIOCGET -      The mt_dsreg field in the returned mtget structure
4062  *                      will be set to (user block size in bytes <<
4063  *                      MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK.
4064  *
4065  *                      The mt_blkno is set to the current user block number.
4066  *                      The other mtget fields are not supported.
4067  *
4068  *      MTIOCPOS -      The current tape "block position" is returned. We
4069  *                      assume that each block contains user_block_size
4070  *                      bytes.
4071  *
4072  *      Our own ide-tape ioctls are supported on both interfaces.
4073  */
4074 static int idetape_chrdev_ioctl (struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
4075 {
4076         struct ide_tape_obj *tape = ide_tape_f(file);
4077         ide_drive_t *drive = tape->drive;
4078         struct mtop mtop;
4079         struct mtget mtget;
4080         struct mtpos mtpos;
4081         int block_offset = 0, position = tape->first_frame_position;
4082         void __user *argp = (void __user *)arg;
4083
4084 #if IDETAPE_DEBUG_LOG
4085         if (tape->debug_level >= 3)
4086                 printk(KERN_INFO "ide-tape: Reached idetape_chrdev_ioctl, "
4087                         "cmd=%u\n", cmd);
4088 #endif /* IDETAPE_DEBUG_LOG */
4089
4090         tape->restart_speed_control_req = 1;
4091         if (tape->chrdev_direction == idetape_direction_write) {
4092                 idetape_empty_write_pipeline(drive);
4093                 idetape_flush_tape_buffers(drive);
4094         }
4095         if (cmd == MTIOCGET || cmd == MTIOCPOS) {
4096                 block_offset = idetape_pipeline_size(drive) / (tape->tape_block_size * tape->user_bs_factor);
4097                 if ((position = idetape_read_position(drive)) < 0)
4098                         return -EIO;
4099         }
4100         switch (cmd) {
4101                 case MTIOCTOP:
4102                         if (copy_from_user(&mtop, argp, sizeof (struct mtop)))
4103                                 return -EFAULT;
4104                         return (idetape_mtioctop(drive,mtop.mt_op,mtop.mt_count));
4105                 case MTIOCGET:
4106                         memset(&mtget, 0, sizeof (struct mtget));
4107                         mtget.mt_type = MT_ISSCSI2;
4108                         mtget.mt_blkno = position / tape->user_bs_factor - block_offset;
4109                         mtget.mt_dsreg = ((tape->tape_block_size * tape->user_bs_factor) << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK;
4110                         if (tape->drv_write_prot) {
4111                                 mtget.mt_gstat |= GMT_WR_PROT(0xffffffff);
4112                         }
4113                         if (copy_to_user(argp, &mtget, sizeof(struct mtget)))
4114                                 return -EFAULT;
4115                         return 0;
4116                 case MTIOCPOS:
4117                         mtpos.mt_blkno = position / tape->user_bs_factor - block_offset;
4118                         if (copy_to_user(argp, &mtpos, sizeof(struct mtpos)))
4119                                 return -EFAULT;
4120                         return 0;
4121                 default:
4122                         if (tape->chrdev_direction == idetape_direction_read)
4123                                 idetape_discard_read_pipeline(drive, 1);
4124                         return idetape_blkdev_ioctl(drive, cmd, arg);
4125         }
4126 }
4127
4128 static void idetape_get_blocksize_from_block_descriptor(ide_drive_t *drive);
4129
4130 /*
4131  *      Our character device open function.
4132  */
4133 static int idetape_chrdev_open (struct inode *inode, struct file *filp)
4134 {
4135         unsigned int minor = iminor(inode), i = minor & ~0xc0;
4136         ide_drive_t *drive;
4137         idetape_tape_t *tape;
4138         idetape_pc_t pc;
4139         int retval;
4140
4141         /*
4142          * We really want to do nonseekable_open(inode, filp); here, but some
4143          * versions of tar incorrectly call lseek on tapes and bail out if that
4144          * fails.  So we disallow pread() and pwrite(), but permit lseeks.
4145          */
4146         filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
4147
4148 #if IDETAPE_DEBUG_LOG
4149         printk(KERN_INFO "ide-tape: Reached idetape_chrdev_open\n");
4150 #endif /* IDETAPE_DEBUG_LOG */
4151
4152         if (i >= MAX_HWIFS * MAX_DRIVES)
4153                 return -ENXIO;
4154
4155         if (!(tape = ide_tape_chrdev_get(i)))
4156                 return -ENXIO;
4157
4158         drive = tape->drive;
4159
4160         filp->private_data = tape;
4161
4162         if (test_and_set_bit(IDETAPE_BUSY, &tape->flags)) {
4163                 retval = -EBUSY;
4164                 goto out_put_tape;
4165         }
4166
4167         retval = idetape_wait_ready(drive, 60 * HZ);
4168         if (retval) {
4169                 clear_bit(IDETAPE_BUSY, &tape->flags);
4170                 printk(KERN_ERR "ide-tape: %s: drive not ready\n", tape->name);
4171                 goto out_put_tape;
4172         }
4173
4174         idetape_read_position(drive);
4175         if (!test_bit(IDETAPE_ADDRESS_VALID, &tape->flags))
4176                 (void)idetape_rewind_tape(drive);
4177
4178         if (tape->chrdev_direction != idetape_direction_read)
4179                 clear_bit(IDETAPE_PIPELINE_ERROR, &tape->flags);
4180
4181         /* Read block size and write protect status from drive. */
4182         idetape_get_blocksize_from_block_descriptor(drive);
4183
4184         /* Set write protect flag if device is opened as read-only. */
4185         if ((filp->f_flags & O_ACCMODE) == O_RDONLY)
4186                 tape->write_prot = 1;
4187         else
4188                 tape->write_prot = tape->drv_write_prot;
4189
4190         /* Make sure drive isn't write protected if user wants to write. */
4191         if (tape->write_prot) {
4192                 if ((filp->f_flags & O_ACCMODE) == O_WRONLY ||
4193                     (filp->f_flags & O_ACCMODE) == O_RDWR) {
4194                         clear_bit(IDETAPE_BUSY, &tape->flags);
4195                         retval = -EROFS;
4196                         goto out_put_tape;
4197                 }
4198         }
4199
4200         /*
4201          * Lock the tape drive door so user can't eject.
4202          */
4203         if (tape->chrdev_direction == idetape_direction_none) {
4204                 if (idetape_create_prevent_cmd(drive, &pc, 1)) {
4205                         if (!idetape_queue_pc_tail(drive, &pc)) {
4206                                 if (tape->door_locked != DOOR_EXPLICITLY_LOCKED)
4207                                         tape->door_locked = DOOR_LOCKED;
4208                         }
4209                 }
4210         }
4211         idetape_restart_speed_control(drive);
4212         tape->restart_speed_control_req = 0;
4213         return 0;
4214
4215 out_put_tape:
4216         ide_tape_put(tape);
4217         return retval;
4218 }
4219
4220 static void idetape_write_release (ide_drive_t *drive, unsigned int minor)
4221 {
4222         idetape_tape_t *tape = drive->driver_data;
4223
4224         idetape_empty_write_pipeline(drive);
4225         tape->merge_stage = __idetape_kmalloc_stage(tape, 1, 0);
4226         if (tape->merge_stage != NULL) {
4227                 idetape_pad_zeros(drive, tape->tape_block_size * (tape->user_bs_factor - 1));
4228                 __idetape_kfree_stage(tape->merge_stage);
4229                 tape->merge_stage = NULL;
4230         }
4231         idetape_write_filemark(drive);
4232         idetape_flush_tape_buffers(drive);
4233         idetape_flush_tape_buffers(drive);
4234 }
4235
4236 /*
4237  *      Our character device release function.
4238  */
4239 static int idetape_chrdev_release (struct inode *inode, struct file *filp)
4240 {
4241         struct ide_tape_obj *tape = ide_tape_f(filp);
4242         ide_drive_t *drive = tape->drive;
4243         idetape_pc_t pc;
4244         unsigned int minor = iminor(inode);
4245
4246         lock_kernel();
4247         tape = drive->driver_data;
4248 #if IDETAPE_DEBUG_LOG
4249         if (tape->debug_level >= 3)
4250                 printk(KERN_INFO "ide-tape: Reached idetape_chrdev_release\n");
4251 #endif /* IDETAPE_DEBUG_LOG */
4252
4253         if (tape->chrdev_direction == idetape_direction_write)
4254                 idetape_write_release(drive, minor);
4255         if (tape->chrdev_direction == idetape_direction_read) {
4256                 if (minor < 128)
4257                         idetape_discard_read_pipeline(drive, 1);
4258                 else
4259                         idetape_wait_for_pipeline(drive);
4260         }
4261         if (tape->cache_stage != NULL) {
4262                 __idetape_kfree_stage(tape->cache_stage);
4263                 tape->cache_stage = NULL;
4264         }
4265         if (minor < 128 && test_bit(IDETAPE_MEDIUM_PRESENT, &tape->flags))
4266                 (void) idetape_rewind_tape(drive);
4267         if (tape->chrdev_direction == idetape_direction_none) {
4268                 if (tape->door_locked == DOOR_LOCKED) {
4269                         if (idetape_create_prevent_cmd(drive, &pc, 0)) {
4270                                 if (!idetape_queue_pc_tail(drive, &pc))
4271                                         tape->door_locked = DOOR_UNLOCKED;
4272                         }
4273                 }
4274         }
4275         clear_bit(IDETAPE_BUSY, &tape->flags);
4276         ide_tape_put(tape);
4277         unlock_kernel();
4278         return 0;
4279 }
4280
4281 /*
4282  *      idetape_identify_device is called to check the contents of the
4283  *      ATAPI IDENTIFY command results. We return:
4284  *
4285  *      1       If the tape can be supported by us, based on the information
4286  *              we have so far.
4287  *
4288  *      0       If this tape driver is not currently supported by us.
4289  */
4290 static int idetape_identify_device (ide_drive_t *drive)
4291 {
4292         struct idetape_id_gcw gcw;
4293         struct hd_driveid *id = drive->id;
4294 #if IDETAPE_DEBUG_INFO
4295         unsigned short mask,i;
4296 #endif /* IDETAPE_DEBUG_INFO */
4297
4298         if (drive->id_read == 0)
4299                 return 1;
4300
4301         *((unsigned short *) &gcw) = id->config;
4302
4303 #if IDETAPE_DEBUG_INFO
4304         printk(KERN_INFO "ide-tape: Dumping ATAPI Identify Device tape parameters\n");
4305         printk(KERN_INFO "ide-tape: Protocol Type: ");
4306         switch (gcw.protocol) {
4307                 case 0: case 1: printk("ATA\n");break;
4308                 case 2: printk("ATAPI\n");break;
4309                 case 3: printk("Reserved (Unknown to ide-tape)\n");break;
4310         }
4311         printk(KERN_INFO "ide-tape: Device Type: %x - ",gcw.device_type);
4312         switch (gcw.device_type) {
4313                 case 0: printk("Direct-access Device\n");break;
4314                 case 1: printk("Streaming Tape Device\n");break;
4315                 case 2: case 3: case 4: printk("Reserved\n");break;
4316                 case 5: printk("CD-ROM Device\n");break;
4317                 case 6: printk("Reserved\n");
4318                 case 7: printk("Optical memory Device\n");break;
4319                 case 0x1f: printk("Unknown or no Device type\n");break;
4320                 default: printk("Reserved\n");
4321         }
4322         printk(KERN_INFO "ide-tape: Removable: %s",gcw.removable ? "Yes\n":"No\n");
4323         printk(KERN_INFO "ide-tape: Command Packet DRQ Type: ");
4324         switch (gcw.drq_type) {
4325                 case 0: printk("Microprocessor DRQ\n");break;
4326                 case 1: printk("Interrupt DRQ\n");break;
4327                 case 2: printk("Accelerated DRQ\n");break;
4328                 case 3: printk("Reserved\n");break;
4329         }
4330         printk(KERN_INFO "ide-tape: Command Packet Size: ");
4331         switch (gcw.packet_size) {
4332                 case 0: printk("12 bytes\n");break;
4333                 case 1: printk("16 bytes\n");break;
4334                 default: printk("Reserved\n");break;
4335         }
4336         printk(KERN_INFO "ide-tape: Model: %.40s\n",id->model);
4337         printk(KERN_INFO "ide-tape: Firmware Revision: %.8s\n",id->fw_rev);
4338         printk(KERN_INFO "ide-tape: Serial Number: %.20s\n",id->serial_no);
4339         printk(KERN_INFO "ide-tape: Write buffer size: %d bytes\n",id->buf_size*512);
4340         printk(KERN_INFO "ide-tape: DMA: %s",id->capability & 0x01 ? "Yes\n":"No\n");
4341         printk(KERN_INFO "ide-tape: LBA: %s",id->capability & 0x02 ? "Yes\n":"No\n");
4342         printk(KERN_INFO "ide-tape: IORDY can be disabled: %s",id->capability & 0x04 ? "Yes\n":"No\n");
4343         printk(KERN_INFO "ide-tape: IORDY supported: %s",id->capability & 0x08 ? "Yes\n":"Unknown\n");
4344         printk(KERN_INFO "ide-tape: ATAPI overlap supported: %s",id->capability & 0x20 ? "Yes\n":"No\n");
4345         printk(KERN_INFO "ide-tape: PIO Cycle Timing Category: %d\n",id->tPIO);
4346         printk(KERN_INFO "ide-tape: DMA Cycle Timing Category: %d\n",id->tDMA);
4347         printk(KERN_INFO "ide-tape: Single Word DMA supported modes: ");
4348         for (i=0,mask=1;i<8;i++,mask=mask << 1) {
4349                 if (id->dma_1word & mask)
4350                         printk("%d ",i);
4351                 if (id->dma_1word & (mask << 8))
4352                         printk("(active) ");
4353         }
4354         printk("\n");
4355         printk(KERN_INFO "ide-tape: Multi Word DMA supported modes: ");
4356         for (i=0,mask=1;i<8;i++,mask=mask << 1) {
4357                 if (id->dma_mword & mask)
4358                         printk("%d ",i);
4359                 if (id->dma_mword & (mask << 8))
4360                         printk("(active) ");
4361         }
4362         printk("\n");
4363         if (id->field_valid & 0x0002) {
4364                 printk(KERN_INFO "ide-tape: Enhanced PIO Modes: %s\n",
4365                         id->eide_pio_modes & 1 ? "Mode 3":"None");
4366                 printk(KERN_INFO "ide-tape: Minimum Multi-word DMA cycle per word: ");
4367                 if (id->eide_dma_min == 0)
4368                         printk("Not supported\n");
4369                 else
4370                         printk("%d ns\n",id->eide_dma_min);
4371
4372                 printk(KERN_INFO "ide-tape: Manufacturer\'s Recommended Multi-word cycle: ");
4373                 if (id->eide_dma_time == 0)
4374                         printk("Not supported\n");
4375                 else
4376                         printk("%d ns\n",id->eide_dma_time);
4377
4378                 printk(KERN_INFO "ide-tape: Minimum PIO cycle without IORDY: ");
4379                 if (id->eide_pio == 0)
4380                         printk("Not supported\n");
4381                 else
4382                         printk("%d ns\n",id->eide_pio);
4383
4384                 printk(KERN_INFO "ide-tape: Minimum PIO cycle with IORDY: ");
4385                 if (id->eide_pio_iordy == 0)
4386                         printk("Not supported\n");
4387                 else
4388                         printk("%d ns\n",id->eide_pio_iordy);
4389
4390         } else
4391                 printk(KERN_INFO "ide-tape: According to the device, fields 64-70 are not valid.\n");
4392 #endif /* IDETAPE_DEBUG_INFO */
4393
4394         /* Check that we can support this device */
4395
4396         if (gcw.protocol !=2 )
4397                 printk(KERN_ERR "ide-tape: Protocol is not ATAPI\n");
4398         else if (gcw.device_type != 1)
4399                 printk(KERN_ERR "ide-tape: Device type is not set to tape\n");
4400         else if (!gcw.removable)
4401                 printk(KERN_ERR "ide-tape: The removable flag is not set\n");
4402         else if (gcw.packet_size != 0) {
4403                 printk(KERN_ERR "ide-tape: Packet size is not 12 bytes long\n");
4404                 if (gcw.packet_size == 1)
4405                         printk(KERN_ERR "ide-tape: Sorry, padding to 16 bytes is still not supported\n");
4406         } else
4407                 return 1;
4408         return 0;
4409 }
4410
4411 /*
4412  * Use INQUIRY to get the firmware revision
4413  */
4414 static void idetape_get_inquiry_results (ide_drive_t *drive)
4415 {
4416         char *r;
4417         idetape_tape_t *tape = drive->driver_data;
4418         idetape_pc_t pc;
4419         idetape_inquiry_result_t *inquiry;
4420
4421         idetape_create_inquiry_cmd(&pc);
4422         if (idetape_queue_pc_tail(drive, &pc)) {
4423                 printk(KERN_ERR "ide-tape: %s: can't get INQUIRY results\n", tape->name);
4424                 return;
4425         }
4426         inquiry = (idetape_inquiry_result_t *) pc.buffer;
4427         memcpy(tape->vendor_id, inquiry->vendor_id, 8);
4428         memcpy(tape->product_id, inquiry->product_id, 16);
4429         memcpy(tape->firmware_revision, inquiry->revision_level, 4);
4430         ide_fixstring(tape->vendor_id, 10, 0);
4431         ide_fixstring(tape->product_id, 18, 0);
4432         ide_fixstring(tape->firmware_revision, 6, 0);
4433         r = tape->firmware_revision;
4434         if (*(r + 1) == '.')
4435                 tape->firmware_revision_num = (*r - '0') * 100 + (*(r + 2) - '0') * 10 + *(r + 3) - '0';
4436         printk(KERN_INFO "ide-tape: %s <-> %s: %s %s rev %s\n", drive->name, tape->name, tape->vendor_id, tape->product_id, tape->firmware_revision);
4437 }
4438
4439 /*
4440  *      idetape_get_mode_sense_results asks the tape about its various
4441  *      parameters. In particular, we will adjust our data transfer buffer
4442  *      size to the recommended value as returned by the tape.
4443  */
4444 static void idetape_get_mode_sense_results (ide_drive_t *drive)
4445 {
4446         idetape_tape_t *tape = drive->driver_data;
4447         idetape_pc_t pc;
4448         idetape_mode_parameter_header_t *header;
4449         idetape_capabilities_page_t *capabilities;
4450
4451         idetape_create_mode_sense_cmd(&pc, IDETAPE_CAPABILITIES_PAGE);
4452         if (idetape_queue_pc_tail(drive, &pc)) {
4453                 printk(KERN_ERR "ide-tape: Can't get tape parameters - assuming some default values\n");
4454                 tape->tape_block_size = 512;
4455                 tape->capabilities.ctl = 52;
4456                 tape->capabilities.speed = 450;
4457                 tape->capabilities.buffer_size = 6 * 52;
4458                 return;
4459         }
4460         header = (idetape_mode_parameter_header_t *) pc.buffer;
4461         capabilities = (idetape_capabilities_page_t *) (pc.buffer + sizeof(idetape_mode_parameter_header_t) + header->bdl);
4462
4463         capabilities->max_speed = ntohs(capabilities->max_speed);
4464         capabilities->ctl = ntohs(capabilities->ctl);
4465         capabilities->speed = ntohs(capabilities->speed);
4466         capabilities->buffer_size = ntohs(capabilities->buffer_size);
4467
4468         if (!capabilities->speed) {
4469                 printk(KERN_INFO "ide-tape: %s: overriding capabilities->speed (assuming 650KB/sec)\n", drive->name);
4470                 capabilities->speed = 650;
4471         }
4472         if (!capabilities->max_speed) {
4473                 printk(KERN_INFO "ide-tape: %s: overriding capabilities->max_speed (assuming 650KB/sec)\n", drive->name);
4474                 capabilities->max_speed = 650;
4475         }
4476
4477         tape->capabilities = *capabilities;             /* Save us a copy */
4478         if (capabilities->blk512)
4479                 tape->tape_block_size = 512;
4480         else if (capabilities->blk1024)
4481                 tape->tape_block_size = 1024;
4482
4483 #if IDETAPE_DEBUG_INFO
4484         printk(KERN_INFO "ide-tape: Dumping the results of the MODE SENSE packet command\n");
4485         printk(KERN_INFO "ide-tape: Mode Parameter Header:\n");
4486         printk(KERN_INFO "ide-tape: Mode Data Length - %d\n",header->mode_data_length);
4487         printk(KERN_INFO "ide-tape: Medium Type - %d\n",header->medium_type);
4488         printk(KERN_INFO "ide-tape: Device Specific Parameter - %d\n",header->dsp);
4489         printk(KERN_INFO "ide-tape: Block Descriptor Length - %d\n",header->bdl);
4490
4491         printk(KERN_INFO "ide-tape: Capabilities and Mechanical Status Page:\n");
4492         printk(KERN_INFO "ide-tape: Page code - %d\n",capabilities->page_code);
4493         printk(KERN_INFO "ide-tape: Page length - %d\n",capabilities->page_length);
4494         printk(KERN_INFO "ide-tape: Read only - %s\n",capabilities->ro ? "Yes":"No");
4495         printk(KERN_INFO "ide-tape: Supports reverse space - %s\n",capabilities->sprev ? "Yes":"No");
4496         printk(KERN_INFO "ide-tape: Supports erase initiated formatting - %s\n",capabilities->efmt ? "Yes":"No");
4497         printk(KERN_INFO "ide-tape: Supports QFA two Partition format - %s\n",capabilities->qfa ? "Yes":"No");
4498         printk(KERN_INFO "ide-tape: Supports locking the medium - %s\n",capabilities->lock ? "Yes":"No");
4499         printk(KERN_INFO "ide-tape: The volume is currently locked - %s\n",capabilities->locked ? "Yes":"No");
4500         printk(KERN_INFO "ide-tape: The device defaults in the prevent state - %s\n",capabilities->prevent ? "Yes":"No");
4501         printk(KERN_INFO "ide-tape: Supports ejecting the medium - %s\n",capabilities->eject ? "Yes":"No");
4502         printk(KERN_INFO "ide-tape: Supports error correction - %s\n",capabilities->ecc ? "Yes":"No");
4503         printk(KERN_INFO "ide-tape: Supports data compression - %s\n",capabilities->cmprs ? "Yes":"No");
4504         printk(KERN_INFO "ide-tape: Supports 512 bytes block size - %s\n",capabilities->blk512 ? "Yes":"No");
4505         printk(KERN_INFO "ide-tape: Supports 1024 bytes block size - %s\n",capabilities->blk1024 ? "Yes":"No");
4506         printk(KERN_INFO "ide-tape: Supports 32768 bytes block size / Restricted byte count for PIO transfers - %s\n",capabilities->blk32768 ? "Yes":"No");
4507         printk(KERN_INFO "ide-tape: Maximum supported speed in KBps - %d\n",capabilities->max_speed);
4508         printk(KERN_INFO "ide-tape: Continuous transfer limits in blocks - %d\n",capabilities->ctl);
4509         printk(KERN_INFO "ide-tape: Current speed in KBps - %d\n",capabilities->speed);
4510         printk(KERN_INFO "ide-tape: Buffer size - %d\n",capabilities->buffer_size*512);
4511 #endif /* IDETAPE_DEBUG_INFO */
4512 }
4513
4514 /*
4515  *      ide_get_blocksize_from_block_descriptor does a mode sense page 0 with block descriptor
4516  *      and if it succeeds sets the tape block size with the reported value
4517  */
4518 static void idetape_get_blocksize_from_block_descriptor(ide_drive_t *drive)
4519 {
4520
4521         idetape_tape_t *tape = drive->driver_data;
4522         idetape_pc_t pc;
4523         idetape_mode_parameter_header_t *header;
4524         idetape_parameter_block_descriptor_t *block_descrp;
4525
4526         idetape_create_mode_sense_cmd(&pc, IDETAPE_BLOCK_DESCRIPTOR);
4527         if (idetape_queue_pc_tail(drive, &pc)) {
4528                 printk(KERN_ERR "ide-tape: Can't get block descriptor\n");
4529                 if (tape->tape_block_size == 0) {
4530                         printk(KERN_WARNING "ide-tape: Cannot deal with zero block size, assume 32k\n");
4531                         tape->tape_block_size =  32768;
4532                 }
4533                 return;
4534         }
4535         header = (idetape_mode_parameter_header_t *) pc.buffer;
4536         block_descrp = (idetape_parameter_block_descriptor_t *) (pc.buffer + sizeof(idetape_mode_parameter_header_t));
4537         tape->tape_block_size =( block_descrp->length[0]<<16) + (block_descrp->length[1]<<8) + block_descrp->length[2];
4538         tape->drv_write_prot = (header->dsp & 0x80) >> 7;
4539
4540 #if IDETAPE_DEBUG_INFO
4541         printk(KERN_INFO "ide-tape: Adjusted block size - %d\n", tape->tape_block_size);
4542 #endif /* IDETAPE_DEBUG_INFO */
4543 }
4544
4545 #ifdef CONFIG_IDE_PROC_FS
4546 static void idetape_add_settings (ide_drive_t *drive)
4547 {
4548         idetape_tape_t *tape = drive->driver_data;
4549
4550 /*
4551  *                      drive   setting name            read/write      data type       min                     max                     mul_factor                      div_factor      data pointer                            set function
4552  */
4553         ide_add_setting(drive,  "buffer",               SETTING_READ,   TYPE_SHORT,     0,                      0xffff,                 1,                              2,              &tape->capabilities.buffer_size,        NULL);
4554         ide_add_setting(drive,  "pipeline_min",         SETTING_RW,     TYPE_INT,       1,                      0xffff,                 tape->stage_size / 1024,        1,              &tape->min_pipeline,                    NULL);
4555         ide_add_setting(drive,  "pipeline",             SETTING_RW,     TYPE_INT,       1,                      0xffff,                 tape->stage_size / 1024,        1,              &tape->max_stages,                      NULL);
4556         ide_add_setting(drive,  "pipeline_max",         SETTING_RW,     TYPE_INT,       1,                      0xffff,                 tape->stage_size / 1024,        1,              &tape->max_pipeline,                    NULL);
4557         ide_add_setting(drive,  "pipeline_used",        SETTING_READ,   TYPE_INT,       0,                      0xffff,                 tape->stage_size / 1024,        1,              &tape->nr_stages,                       NULL);
4558         ide_add_setting(drive,  "pipeline_pending",     SETTING_READ,   TYPE_INT,       0,                      0xffff,                 tape->stage_size / 1024,        1,              &tape->nr_pending_stages,               NULL);
4559         ide_add_setting(drive,  "speed",                SETTING_READ,   TYPE_SHORT,     0,                      0xffff,                 1,                              1,              &tape->capabilities.speed,              NULL);
4560         ide_add_setting(drive,  "stage",                SETTING_READ,   TYPE_INT,       0,                      0xffff,                 1,                              1024,           &tape->stage_size,                      NULL);
4561         ide_add_setting(drive,  "tdsc",                 SETTING_RW,     TYPE_INT,       IDETAPE_DSC_RW_MIN,     IDETAPE_DSC_RW_MAX,     1000,                           HZ,             &tape->best_dsc_rw_frequency,           NULL);
4562         ide_add_setting(drive,  "dsc_overlap",          SETTING_RW,     TYPE_BYTE,      0,                      1,                      1,                              1,              &drive->dsc_overlap,                    NULL);
4563         ide_add_setting(drive,  "pipeline_head_speed_c",SETTING_READ,   TYPE_INT,       0,                      0xffff,                 1,                              1,              &tape->controlled_pipeline_head_speed,  NULL);
4564         ide_add_setting(drive,  "pipeline_head_speed_u",SETTING_READ,   TYPE_INT,       0,                      0xffff,                 1,                              1,              &tape->uncontrolled_pipeline_head_speed,NULL);
4565         ide_add_setting(drive,  "avg_speed",            SETTING_READ,   TYPE_INT,       0,                      0xffff,                 1,                              1,              &tape->avg_speed,                       NULL);
4566         ide_add_setting(drive,  "debug_level",          SETTING_RW,     TYPE_INT,       0,                      0xffff,                 1,                              1,              &tape->debug_level,                     NULL);
4567 }
4568 #else
4569 static inline void idetape_add_settings(ide_drive_t *drive) { ; }
4570 #endif
4571
4572 /*
4573  *      ide_setup is called to:
4574  *
4575  *              1.      Initialize our various state variables.
4576  *              2.      Ask the tape for its capabilities.
4577  *              3.      Allocate a buffer which will be used for data
4578  *                      transfer. The buffer size is chosen based on
4579  *                      the recommendation which we received in step (2).
4580  *
4581  *      Note that at this point ide.c already assigned us an irq, so that
4582  *      we can queue requests here and wait for their completion.
4583  */
4584 static void idetape_setup (ide_drive_t *drive, idetape_tape_t *tape, int minor)
4585 {
4586         unsigned long t1, tmid, tn, t;
4587         int speed;
4588         struct idetape_id_gcw gcw;
4589         int stage_size;
4590         struct sysinfo si;
4591
4592         spin_lock_init(&tape->spinlock);
4593         drive->dsc_overlap = 1;
4594 #ifdef CONFIG_BLK_DEV_IDEPCI
4595         if (HWIF(drive)->pci_dev != NULL) {
4596                 /*
4597                  * These two ide-pci host adapters appear to need DSC overlap disabled.
4598                  * This probably needs further analysis.
4599                  */
4600                 if ((HWIF(drive)->pci_dev->device == PCI_DEVICE_ID_ARTOP_ATP850UF) ||
4601                     (HWIF(drive)->pci_dev->device == PCI_DEVICE_ID_TTI_HPT343)) {
4602                         printk(KERN_INFO "ide-tape: %s: disabling DSC overlap\n", tape->name);
4603                         drive->dsc_overlap = 0;
4604                 }
4605         }
4606 #endif /* CONFIG_BLK_DEV_IDEPCI */
4607         /* Seagate Travan drives do not support DSC overlap. */
4608         if (strstr(drive->id->model, "Seagate STT3401"))
4609                 drive->dsc_overlap = 0;
4610         tape->minor = minor;
4611         tape->name[0] = 'h';
4612         tape->name[1] = 't';
4613         tape->name[2] = '0' + minor;
4614         tape->chrdev_direction = idetape_direction_none;
4615         tape->pc = tape->pc_stack;
4616         tape->max_insert_speed = 10000;
4617         tape->speed_control = 1;
4618         *((unsigned short *) &gcw) = drive->id->config;
4619         if (gcw.drq_type == 1)
4620                 set_bit(IDETAPE_DRQ_INTERRUPT, &tape->flags);
4621
4622         tape->min_pipeline = tape->max_pipeline = tape->max_stages = 10;
4623
4624         idetape_get_inquiry_results(drive);
4625         idetape_get_mode_sense_results(drive);
4626         idetape_get_blocksize_from_block_descriptor(drive);
4627         tape->user_bs_factor = 1;
4628         tape->stage_size = tape->capabilities.ctl * tape->tape_block_size;
4629         while (tape->stage_size > 0xffff) {
4630                 printk(KERN_NOTICE "ide-tape: decreasing stage size\n");
4631                 tape->capabilities.ctl /= 2;
4632                 tape->stage_size = tape->capabilities.ctl * tape->tape_block_size;
4633         }
4634         stage_size = tape->stage_size;
4635         tape->pages_per_stage = stage_size / PAGE_SIZE;
4636         if (stage_size % PAGE_SIZE) {
4637                 tape->pages_per_stage++;
4638                 tape->excess_bh_size = PAGE_SIZE - stage_size % PAGE_SIZE;
4639         }
4640
4641         /*
4642          *      Select the "best" DSC read/write polling frequency
4643          *      and pipeline size.
4644          */
4645         speed = max(tape->capabilities.speed, tape->capabilities.max_speed);
4646
4647         tape->max_stages = speed * 1000 * 10 / tape->stage_size;
4648
4649         /*
4650          *      Limit memory use for pipeline to 10% of physical memory
4651          */
4652         si_meminfo(&si);
4653         if (tape->max_stages * tape->stage_size > si.totalram * si.mem_unit / 10)
4654                 tape->max_stages = si.totalram * si.mem_unit / (10 * tape->stage_size);
4655         tape->max_stages   = min(tape->max_stages, IDETAPE_MAX_PIPELINE_STAGES);
4656         tape->min_pipeline = min(tape->max_stages, IDETAPE_MIN_PIPELINE_STAGES);
4657         tape->max_pipeline = min(tape->max_stages * 2, IDETAPE_MAX_PIPELINE_STAGES);
4658         if (tape->max_stages == 0)
4659                 tape->max_stages = tape->min_pipeline = tape->max_pipeline = 1;
4660
4661         t1 = (tape->stage_size * HZ) / (speed * 1000);
4662         tmid = (tape->capabilities.buffer_size * 32 * HZ) / (speed * 125);
4663         tn = (IDETAPE_FIFO_THRESHOLD * tape->stage_size * HZ) / (speed * 1000);
4664
4665         if (tape->max_stages)
4666                 t = tn;
4667         else
4668                 t = t1;
4669
4670         /*
4671          *      Ensure that the number we got makes sense; limit
4672          *      it within IDETAPE_DSC_RW_MIN and IDETAPE_DSC_RW_MAX.
4673          */
4674         tape->best_dsc_rw_frequency = max_t(unsigned long, min_t(unsigned long, t, IDETAPE_DSC_RW_MAX), IDETAPE_DSC_RW_MIN);
4675         printk(KERN_INFO "ide-tape: %s <-> %s: %dKBps, %d*%dkB buffer, "
4676                 "%dkB pipeline, %lums tDSC%s\n",
4677                 drive->name, tape->name, tape->capabilities.speed,
4678                 (tape->capabilities.buffer_size * 512) / tape->stage_size,
4679                 tape->stage_size / 1024,
4680                 tape->max_stages * tape->stage_size / 1024,
4681                 tape->best_dsc_rw_frequency * 1000 / HZ,
4682                 drive->using_dma ? ", DMA":"");
4683
4684         idetape_add_settings(drive);
4685 }
4686
4687 static void ide_tape_remove(ide_drive_t *drive)
4688 {
4689         idetape_tape_t *tape = drive->driver_data;
4690
4691         ide_proc_unregister_driver(drive, tape->driver);
4692
4693         ide_unregister_region(tape->disk);
4694
4695         ide_tape_put(tape);
4696 }
4697
4698 static void ide_tape_release(struct kref *kref)
4699 {
4700         struct ide_tape_obj *tape = to_ide_tape(kref);
4701         ide_drive_t *drive = tape->drive;
4702         struct gendisk *g = tape->disk;
4703
4704         BUG_ON(tape->first_stage != NULL || tape->merge_stage_size);
4705
4706         drive->dsc_overlap = 0;
4707         drive->driver_data = NULL;
4708         device_destroy(idetape_sysfs_class, MKDEV(IDETAPE_MAJOR, tape->minor));
4709         device_destroy(idetape_sysfs_class, MKDEV(IDETAPE_MAJOR, tape->minor + 128));
4710         idetape_devs[tape->minor] = NULL;
4711         g->private_data = NULL;
4712         put_disk(g);
4713         kfree(tape);
4714 }
4715
4716 #ifdef CONFIG_IDE_PROC_FS
4717 static int proc_idetape_read_name
4718         (char *page, char **start, off_t off, int count, int *eof, void *data)
4719 {
4720         ide_drive_t     *drive = (ide_drive_t *) data;
4721         idetape_tape_t  *tape = drive->driver_data;
4722         char            *out = page;
4723         int             len;
4724
4725         len = sprintf(out, "%s\n", tape->name);
4726         PROC_IDE_READ_RETURN(page, start, off, count, eof, len);
4727 }
4728
4729 static ide_proc_entry_t idetape_proc[] = {
4730         { "capacity",   S_IFREG|S_IRUGO,        proc_ide_read_capacity, NULL },
4731         { "name",       S_IFREG|S_IRUGO,        proc_idetape_read_name, NULL },
4732         { NULL, 0, NULL, NULL }
4733 };
4734 #endif
4735
4736 static int ide_tape_probe(ide_drive_t *);
4737
4738 static ide_driver_t idetape_driver = {
4739         .gen_driver = {
4740                 .owner          = THIS_MODULE,
4741                 .name           = "ide-tape",
4742                 .bus            = &ide_bus_type,
4743         },
4744         .probe                  = ide_tape_probe,
4745         .remove                 = ide_tape_remove,
4746         .version                = IDETAPE_VERSION,
4747         .media                  = ide_tape,
4748         .supports_dsc_overlap   = 1,
4749         .do_request             = idetape_do_request,
4750         .end_request            = idetape_end_request,
4751         .error                  = __ide_error,
4752         .abort                  = __ide_abort,
4753 #ifdef CONFIG_IDE_PROC_FS
4754         .proc                   = idetape_proc,
4755 #endif
4756 };
4757
4758 /*
4759  *      Our character device supporting functions, passed to register_chrdev.
4760  */
4761 static const struct file_operations idetape_fops = {
4762         .owner          = THIS_MODULE,
4763         .read           = idetape_chrdev_read,
4764         .write          = idetape_chrdev_write,
4765         .ioctl          = idetape_chrdev_ioctl,
4766         .open           = idetape_chrdev_open,
4767         .release        = idetape_chrdev_release,
4768 };
4769
4770 static int idetape_open(struct inode *inode, struct file *filp)
4771 {
4772         struct gendisk *disk = inode->i_bdev->bd_disk;
4773         struct ide_tape_obj *tape;
4774
4775         if (!(tape = ide_tape_get(disk)))
4776                 return -ENXIO;
4777
4778         return 0;
4779 }
4780
4781 static int idetape_release(struct inode *inode, struct file *filp)
4782 {
4783         struct gendisk *disk = inode->i_bdev->bd_disk;
4784         struct ide_tape_obj *tape = ide_tape_g(disk);
4785
4786         ide_tape_put(tape);
4787
4788         return 0;
4789 }
4790
4791 static int idetape_ioctl(struct inode *inode, struct file *file,
4792                         unsigned int cmd, unsigned long arg)
4793 {
4794         struct block_device *bdev = inode->i_bdev;
4795         struct ide_tape_obj *tape = ide_tape_g(bdev->bd_disk);
4796         ide_drive_t *drive = tape->drive;
4797         int err = generic_ide_ioctl(drive, file, bdev, cmd, arg);
4798         if (err == -EINVAL)
4799                 err = idetape_blkdev_ioctl(drive, cmd, arg);
4800         return err;
4801 }
4802
4803 static struct block_device_operations idetape_block_ops = {
4804         .owner          = THIS_MODULE,
4805         .open           = idetape_open,
4806         .release        = idetape_release,
4807         .ioctl          = idetape_ioctl,
4808 };
4809
4810 static int ide_tape_probe(ide_drive_t *drive)
4811 {
4812         idetape_tape_t *tape;
4813         struct gendisk *g;
4814         int minor;
4815
4816         if (!strstr("ide-tape", drive->driver_req))
4817                 goto failed;
4818         if (!drive->present)
4819                 goto failed;
4820         if (drive->media != ide_tape)
4821                 goto failed;
4822         if (!idetape_identify_device (drive)) {
4823                 printk(KERN_ERR "ide-tape: %s: not supported by this version of ide-tape\n", drive->name);
4824                 goto failed;
4825         }
4826         if (drive->scsi) {
4827                 printk("ide-tape: passing drive %s to ide-scsi emulation.\n", drive->name);
4828                 goto failed;
4829         }
4830         if (strstr(drive->id->model, "OnStream DI-")) {
4831                 printk(KERN_WARNING "ide-tape: Use drive %s with ide-scsi emulation and osst.\n", drive->name);
4832                 printk(KERN_WARNING "ide-tape: OnStream support will be removed soon from ide-tape!\n");
4833         }
4834         tape = kzalloc(sizeof (idetape_tape_t), GFP_KERNEL);
4835         if (tape == NULL) {
4836                 printk(KERN_ERR "ide-tape: %s: Can't allocate a tape structure\n", drive->name);
4837                 goto failed;
4838         }
4839
4840         g = alloc_disk(1 << PARTN_BITS);
4841         if (!g)
4842                 goto out_free_tape;
4843
4844         ide_init_disk(g, drive);
4845
4846         ide_proc_register_driver(drive, &idetape_driver);
4847
4848         kref_init(&tape->kref);
4849
4850         tape->drive = drive;
4851         tape->driver = &idetape_driver;
4852         tape->disk = g;
4853
4854         g->private_data = &tape->driver;
4855
4856         drive->driver_data = tape;
4857
4858         mutex_lock(&idetape_ref_mutex);
4859         for (minor = 0; idetape_devs[minor]; minor++)
4860                 ;
4861         idetape_devs[minor] = tape;
4862         mutex_unlock(&idetape_ref_mutex);
4863
4864         idetape_setup(drive, tape, minor);
4865
4866         device_create(idetape_sysfs_class, &drive->gendev,
4867                       MKDEV(IDETAPE_MAJOR, minor), "%s", tape->name);
4868         device_create(idetape_sysfs_class, &drive->gendev,
4869                         MKDEV(IDETAPE_MAJOR, minor + 128), "n%s", tape->name);
4870
4871         g->fops = &idetape_block_ops;
4872         ide_register_region(g);
4873
4874         return 0;
4875
4876 out_free_tape:
4877         kfree(tape);
4878 failed:
4879         return -ENODEV;
4880 }
4881
4882 MODULE_DESCRIPTION("ATAPI Streaming TAPE Driver");
4883 MODULE_LICENSE("GPL");
4884
4885 static void __exit idetape_exit (void)
4886 {
4887         driver_unregister(&idetape_driver.gen_driver);
4888         class_destroy(idetape_sysfs_class);
4889         unregister_chrdev(IDETAPE_MAJOR, "ht");
4890 }
4891
4892 static int __init idetape_init(void)
4893 {
4894         int error = 1;
4895         idetape_sysfs_class = class_create(THIS_MODULE, "ide_tape");
4896         if (IS_ERR(idetape_sysfs_class)) {
4897                 idetape_sysfs_class = NULL;
4898                 printk(KERN_ERR "Unable to create sysfs class for ide tapes\n");
4899                 error = -EBUSY;
4900                 goto out;
4901         }
4902
4903         if (register_chrdev(IDETAPE_MAJOR, "ht", &idetape_fops)) {
4904                 printk(KERN_ERR "ide-tape: Failed to register character device interface\n");
4905                 error = -EBUSY;
4906                 goto out_free_class;
4907         }
4908
4909         error = driver_register(&idetape_driver.gen_driver);
4910         if (error)
4911                 goto out_free_driver;
4912
4913         return 0;
4914
4915 out_free_driver:
4916         driver_unregister(&idetape_driver.gen_driver);
4917 out_free_class:
4918         class_destroy(idetape_sysfs_class);
4919 out:
4920         return error;
4921 }
4922
4923 MODULE_ALIAS("ide:*m-tape*");
4924 module_init(idetape_init);
4925 module_exit(idetape_exit);
4926 MODULE_ALIAS_CHARDEV_MAJOR(IDETAPE_MAJOR);