drivers/ide/ide-io.c

   1 /*
   2  *      IDE I/O functions
   3  *
   4  *      Basic PIO and command management functionality.
   5  *
   6  * This code was split off from ide.c. See ide.c for history and original
   7  * copyrights.
   8  *
   9  * This program is free software; you can redistribute it and/or modify it
  10  * under the terms of the GNU General Public License as published by the
  11  * Free Software Foundation; either version 2, or (at your option) any
  12  * later version.
  13  *
  14  * This program is distributed in the hope that it will be useful, but
  15  * WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * General Public License for more details.
  18  *
  19  * For the avoidance of doubt the "preferred form" of this code is one which
  20  * is in an open non patent encumbered format. Where cryptographic key signing
  21  * forms part of the process of creating an executable the information
  22  * including keys needed to generate an equivalently functional executable
  23  * are deemed to be part of the source code.
  24  */
  25
  26
  27 #include <linux/module.h>
  28 #include <linux/types.h>
  29 #include <linux/string.h>
  30 #include <linux/kernel.h>
  31 #include <linux/timer.h>
  32 #include <linux/mm.h>
  33 #include <linux/interrupt.h>
  34 #include <linux/major.h>
  35 #include <linux/errno.h>
  36 #include <linux/genhd.h>
  37 #include <linux/blkpg.h>
  38 #include <linux/slab.h>
  39 #include <linux/init.h>
  40 #include <linux/pci.h>
  41 #include <linux/delay.h>
  42 #include <linux/ide.h>
  43 #include <linux/completion.h>
  44 #include <linux/reboot.h>
  45 #include <linux/cdrom.h>
  46 #include <linux/seq_file.h>
  47 #include <linux/device.h>
  48 #include <linux/kmod.h>
  49 #include <linux/scatterlist.h>
  50 #include <linux/bitops.h>
  51
  52 #include <asm/byteorder.h>
  53 #include <asm/irq.h>
  54 #include <linux/uaccess.h>
  55 #include <asm/io.h>
  56
  57 int ide_end_rq(ide_drive_t *drive, struct request *rq, blk_status_t error,
  58                unsigned int nr_bytes)
  59 {
  60         /*
  61          * decide whether to reenable DMA -- 3 is a random magic for now,
  62          * if we DMA timeout more than 3 times, just stay in PIO
  63          */
  64         if ((drive->dev_flags & IDE_DFLAG_DMA_PIO_RETRY) &&
  65             drive->retry_pio <= 3) {
  66                 drive->dev_flags &= ~IDE_DFLAG_DMA_PIO_RETRY;
  67                 ide_dma_on(drive);
  68         }
  69
  70         if (!blk_update_request(rq, error, nr_bytes)) {
  71                 if (rq == drive->sense_rq)
  72                         drive->sense_rq = NULL;
  73
  74                 __blk_mq_end_request(rq, error);
  75                 return 0;
  76         }
  77
  78         return 1;
  79 }
  80 EXPORT_SYMBOL_GPL(ide_end_rq);
  81
  82 void ide_complete_cmd(ide_drive_t *drive, struct ide_cmd *cmd, u8 stat, u8 err)
  83 {
  84         const struct ide_tp_ops *tp_ops = drive->hwif->tp_ops;
  85         struct ide_taskfile *tf = &cmd->tf;
  86         struct request *rq = cmd->rq;
  87         u8 tf_cmd = tf->command;
  88
  89         tf->error = err;
  90         tf->status = stat;
  91
  92         if (cmd->ftf_flags & IDE_FTFLAG_IN_DATA) {
  93                 u8 data[2];
  94
  95                 tp_ops->input_data(drive, cmd, data, 2);
  96
  97                 cmd->tf.data  = data[0];
  98                 cmd->hob.data = data[1];
  99         }
 100
 101         ide_tf_readback(drive, cmd);
 102
 103         if ((cmd->tf_flags & IDE_TFLAG_CUSTOM_HANDLER) &&
 104             tf_cmd == ATA_CMD_IDLEIMMEDIATE) {
 105                 if (tf->lbal != 0xc4) {
 106                         printk(KERN_ERR "%s: head unload failed!\n",
 107                                drive->name);
 108                         ide_tf_dump(drive->name, cmd);
 109                 } else
 110                         drive->dev_flags |= IDE_DFLAG_PARKED;
 111         }
 112
 113         if (rq && ata_taskfile_request(rq)) {
 114                 struct ide_cmd *orig_cmd = ide_req(rq)->special;
 115
 116                 if (cmd->tf_flags & IDE_TFLAG_DYN)
 117                         kfree(orig_cmd);
 118                 else if (cmd != orig_cmd)
 119                         memcpy(orig_cmd, cmd, sizeof(*cmd));
 120         }
 121 }
 122
 123 int ide_complete_rq(ide_drive_t *drive, blk_status_t error, unsigned int nr_bytes)
 124 {
 125         ide_hwif_t *hwif = drive->hwif;
 126         struct request *rq = hwif->rq;
 127         int rc;
 128
 129         /*
 130          * if failfast is set on a request, override number of sectors
 131          * and complete the whole request right now
 132          */
 133         if (blk_noretry_request(rq) && error)
 134                 nr_bytes = blk_rq_sectors(rq) << 9;
 135
 136         rc = ide_end_rq(drive, rq, error, nr_bytes);
 137         if (rc == 0)
 138                 hwif->rq = NULL;
 139
 140         return rc;
 141 }
 142 EXPORT_SYMBOL(ide_complete_rq);
 143
 144 void ide_kill_rq(ide_drive_t *drive, struct request *rq)
 145 {
 146         u8 drv_req = ata_misc_request(rq) && rq->rq_disk;
 147         u8 media = drive->media;
 148
 149         drive->failed_pc = NULL;
 150
 151         if ((media == ide_floppy || media == ide_tape) && drv_req) {
 152                 scsi_req(rq)->result = 0;
 153         } else {
 154                 if (media == ide_tape)
 155                         scsi_req(rq)->result = IDE_DRV_ERROR_GENERAL;
 156                 else if (blk_rq_is_passthrough(rq) && scsi_req(rq)->result == 0)
 157                         scsi_req(rq)->result = -EIO;
 158         }
 159
 160         ide_complete_rq(drive, BLK_STS_IOERR, blk_rq_bytes(rq));
 161 }
 162
 163 static void ide_tf_set_specify_cmd(ide_drive_t *drive, struct ide_taskfile *tf)
 164 {
 165         tf->nsect   = drive->sect;
 166         tf->lbal    = drive->sect;
 167         tf->lbam    = drive->cyl;
 168         tf->lbah    = drive->cyl >> 8;
 169         tf->device  = (drive->head - 1) | drive->select;
 170         tf->command = ATA_CMD_INIT_DEV_PARAMS;
 171 }
 172
 173 static void ide_tf_set_restore_cmd(ide_drive_t *drive, struct ide_taskfile *tf)
 174 {
 175         tf->nsect   = drive->sect;
 176         tf->command = ATA_CMD_RESTORE;
 177 }
 178
 179 static void ide_tf_set_setmult_cmd(ide_drive_t *drive, struct ide_taskfile *tf)
 180 {
 181         tf->nsect   = drive->mult_req;
 182         tf->command = ATA_CMD_SET_MULTI;
 183 }
 184
 185 /**
 186  *      do_special              -       issue some special commands
 187  *      @drive: drive the command is for
 188  *
 189  *      do_special() is used to issue ATA_CMD_INIT_DEV_PARAMS,
 190  *      ATA_CMD_RESTORE and ATA_CMD_SET_MULTI commands to a drive.
 191  */
 192
 193 static ide_startstop_t do_special(ide_drive_t *drive)
 194 {
 195         struct ide_cmd cmd;
 196
 197 #ifdef DEBUG
 198         printk(KERN_DEBUG "%s: %s: 0x%02x\n", drive->name, __func__,
 199                 drive->special_flags);
 200 #endif
 201         if (drive->media != ide_disk) {
 202                 drive->special_flags = 0;
 203                 drive->mult_req = 0;
 204                 return ide_stopped;
 205         }
 206
 207         memset(&cmd, 0, sizeof(cmd));
 208         cmd.protocol = ATA_PROT_NODATA;
 209
 210         if (drive->special_flags & IDE_SFLAG_SET_GEOMETRY) {
 211                 drive->special_flags &= ~IDE_SFLAG_SET_GEOMETRY;
 212                 ide_tf_set_specify_cmd(drive, &cmd.tf);
 213         } else if (drive->special_flags & IDE_SFLAG_RECALIBRATE) {
 214                 drive->special_flags &= ~IDE_SFLAG_RECALIBRATE;
 215                 ide_tf_set_restore_cmd(drive, &cmd.tf);
 216         } else if (drive->special_flags & IDE_SFLAG_SET_MULTMODE) {
 217                 drive->special_flags &= ~IDE_SFLAG_SET_MULTMODE;
 218                 ide_tf_set_setmult_cmd(drive, &cmd.tf);
 219         } else
 220                 BUG();
 221
 222         cmd.valid.out.tf = IDE_VALID_OUT_TF | IDE_VALID_DEVICE;
 223         cmd.valid.in.tf  = IDE_VALID_IN_TF  | IDE_VALID_DEVICE;
 224         cmd.tf_flags = IDE_TFLAG_CUSTOM_HANDLER;
 225
 226         do_rw_taskfile(drive, &cmd);
 227
 228         return ide_started;
 229 }
 230
 231 void ide_map_sg(ide_drive_t *drive, struct ide_cmd *cmd)
 232 {
 233         ide_hwif_t *hwif = drive->hwif;
 234         struct scatterlist *sg = hwif->sg_table;
 235         struct request *rq = cmd->rq;
 236
 237         cmd->sg_nents = blk_rq_map_sg(drive->queue, rq, sg);
 238 }
 239 EXPORT_SYMBOL_GPL(ide_map_sg);
 240
 241 void ide_init_sg_cmd(struct ide_cmd *cmd, unsigned int nr_bytes)
 242 {
 243         cmd->nbytes = cmd->nleft = nr_bytes;
 244         cmd->cursg_ofs = 0;
 245         cmd->cursg = NULL;
 246 }
 247 EXPORT_SYMBOL_GPL(ide_init_sg_cmd);
 248
 249 /**
 250  *      execute_drive_command   -       issue special drive command
 251  *      @drive: the drive to issue the command on
 252  *      @rq: the request structure holding the command
 253  *
 254  *      execute_drive_cmd() issues a special drive command,  usually
 255  *      initiated by ioctl() from the external hdparm program. The
 256  *      command can be a drive command, drive task or taskfile
 257  *      operation. Weirdly you can call it with NULL to wait for
 258  *      all commands to finish. Don't do this as that is due to change
 259  */
 260
 261 static ide_startstop_t execute_drive_cmd (ide_drive_t *drive,
 262                 struct request *rq)
 263 {
 264         struct ide_cmd *cmd = ide_req(rq)->special;
 265
 266         if (cmd) {
 267                 if (cmd->protocol == ATA_PROT_PIO) {
 268                         ide_init_sg_cmd(cmd, blk_rq_sectors(rq) << 9);
 269                         ide_map_sg(drive, cmd);
 270                 }
 271
 272                 return do_rw_taskfile(drive, cmd);
 273         }
 274
 275         /*
 276          * NULL is actually a valid way of waiting for
 277          * all current requests to be flushed from the queue.
 278          */
 279 #ifdef DEBUG
 280         printk("%s: DRIVE_CMD (null)\n", drive->name);
 281 #endif
 282         scsi_req(rq)->result = 0;
 283         ide_complete_rq(drive, BLK_STS_OK, blk_rq_bytes(rq));
 284
 285         return ide_stopped;
 286 }
 287
 288 static ide_startstop_t ide_special_rq(ide_drive_t *drive, struct request *rq)
 289 {
 290         u8 cmd = scsi_req(rq)->cmd[0];
 291
 292         switch (cmd) {
 293         case REQ_PARK_HEADS:
 294         case REQ_UNPARK_HEADS:
 295                 return ide_do_park_unpark(drive, rq);
 296         case REQ_DEVSET_EXEC:
 297                 return ide_do_devset(drive, rq);
 298         case REQ_DRIVE_RESET:
 299                 return ide_do_reset(drive);
 300         default:
 301                 BUG();
 302         }
 303 }
 304
 305 /**
 306  *      start_request   -       start of I/O and command issuing for IDE
 307  *
 308  *      start_request() initiates handling of a new I/O request. It
 309  *      accepts commands and I/O (read/write) requests.
 310  *
 311  *      FIXME: this function needs a rename
 312  */
 313
 314 static ide_startstop_t start_request (ide_drive_t *drive, struct request *rq)
 315 {
 316         ide_startstop_t startstop;
 317
 318 #ifdef DEBUG
 319         printk("%s: start_request: current=0x%08lx\n",
 320                 drive->hwif->name, (unsigned long) rq);
 321 #endif
 322
 323         /* bail early if we've exceeded max_failures */
 324         if (drive->max_failures && (drive->failures > drive->max_failures)) {
 325                 rq->rq_flags |= RQF_FAILED;
 326                 goto kill_rq;
 327         }
 328
 329         if (drive->prep_rq && !drive->prep_rq(drive, rq))
 330                 return ide_stopped;
 331
 332         if (ata_pm_request(rq))
 333                 ide_check_pm_state(drive, rq);
 334
 335         drive->hwif->tp_ops->dev_select(drive);
 336         if (ide_wait_stat(&startstop, drive, drive->ready_stat,
 337                           ATA_BUSY | ATA_DRQ, WAIT_READY)) {
 338                 printk(KERN_ERR "%s: drive not ready for command\n", drive->name);
 339                 return startstop;
 340         }
 341
 342         if (drive->special_flags == 0) {
 343                 struct ide_driver *drv;
 344
 345                 /*
 346                  * We reset the drive so we need to issue a SETFEATURES.
 347                  * Do it _after_ do_special() restored device parameters.
 348                  */
 349                 if (drive->current_speed == 0xff)
 350                         ide_config_drive_speed(drive, drive->desired_speed);
 351
 352                 if (ata_taskfile_request(rq))
 353                         return execute_drive_cmd(drive, rq);
 354                 else if (ata_pm_request(rq)) {
 355                         struct ide_pm_state *pm = ide_req(rq)->special;
 356 #ifdef DEBUG_PM
 357                         printk("%s: start_power_step(step: %d)\n",
 358                                 drive->name, pm->pm_step);
 359 #endif
 360                         startstop = ide_start_power_step(drive, rq);
 361                         if (startstop == ide_stopped &&
 362                             pm->pm_step == IDE_PM_COMPLETED)
 363                                 ide_complete_pm_rq(drive, rq);
 364                         return startstop;
 365                 } else if (!rq->rq_disk && ata_misc_request(rq))
 366                         /*
 367                          * TODO: Once all ULDs have been modified to
 368                          * check for specific op codes rather than
 369                          * blindly accepting any special request, the
 370                          * check for ->rq_disk above may be replaced
 371                          * by a more suitable mechanism or even
 372                          * dropped entirely.
 373                          */
 374                         return ide_special_rq(drive, rq);
 375
 376                 drv = *(struct ide_driver **)rq->rq_disk->private_data;
 377
 378                 return drv->do_request(drive, rq, blk_rq_pos(rq));
 379         }
 380         return do_special(drive);
 381 kill_rq:
 382         ide_kill_rq(drive, rq);
 383         return ide_stopped;
 384 }
 385
 386 /**
 387  *      ide_stall_queue         -       pause an IDE device
 388  *      @drive: drive to stall
 389  *      @timeout: time to stall for (jiffies)
 390  *
 391  *      ide_stall_queue() can be used by a drive to give excess bandwidth back
 392  *      to the port by sleeping for timeout jiffies.
 393  */
 394
 395 void ide_stall_queue (ide_drive_t *drive, unsigned long timeout)
 396 {
 397         if (timeout > WAIT_WORSTCASE)
 398                 timeout = WAIT_WORSTCASE;
 399         drive->sleep = timeout + jiffies;
 400         drive->dev_flags |= IDE_DFLAG_SLEEPING;
 401 }
 402 EXPORT_SYMBOL(ide_stall_queue);
 403
 404 static inline int ide_lock_port(ide_hwif_t *hwif)
 405 {
 406         if (hwif->busy)
 407                 return 1;
 408
 409         hwif->busy = 1;
 410
 411         return 0;
 412 }
 413
 414 static inline void ide_unlock_port(ide_hwif_t *hwif)
 415 {
 416         hwif->busy = 0;
 417 }
 418
 419 static inline int ide_lock_host(struct ide_host *host, ide_hwif_t *hwif)
 420 {
 421         int rc = 0;
 422
 423         if (host->host_flags & IDE_HFLAG_SERIALIZE) {
 424                 rc = test_and_set_bit_lock(IDE_HOST_BUSY, &host->host_busy);
 425                 if (rc == 0) {
 426                         if (host->get_lock)
 427                                 host->get_lock(ide_intr, hwif);
 428                 }
 429         }
 430         return rc;
 431 }
 432
 433 static inline void ide_unlock_host(struct ide_host *host)
 434 {
 435         if (host->host_flags & IDE_HFLAG_SERIALIZE) {
 436                 if (host->release_lock)
 437                         host->release_lock();
 438                 clear_bit_unlock(IDE_HOST_BUSY, &host->host_busy);
 439         }
 440 }
 441
 442 void ide_requeue_and_plug(ide_drive_t *drive, struct request *rq)
 443 {
 444         struct request_queue *q = drive->queue;
 445
 446         /* Use 3ms as that was the old plug delay */
 447         if (rq) {
 448                 blk_mq_requeue_request(rq, false);
 449                 blk_mq_delay_kick_requeue_list(q, 3);
 450         } else
 451                 blk_mq_delay_run_hw_queue(q->queue_hw_ctx[0], 3);
 452 }
 453
 454 /*
 455  * Issue a new request to a device.
 456  */
 457 blk_status_t ide_queue_rq(struct blk_mq_hw_ctx *hctx,
 458                           const struct blk_mq_queue_data *bd)
 459 {
 460         ide_drive_t     *drive = hctx->queue->queuedata;
 461         ide_hwif_t      *hwif = drive->hwif;
 462         struct ide_host *host = hwif->host;
 463         struct request  *rq = bd->rq;
 464         ide_startstop_t startstop;
 465
 466         if (!blk_rq_is_passthrough(rq) && !(rq->rq_flags & RQF_DONTPREP)) {
 467                 rq->rq_flags |= RQF_DONTPREP;
 468                 ide_req(rq)->special = NULL;
 469         }
 470
 471         /* HLD do_request() callback might sleep, make sure it's okay */
 472         might_sleep();
 473
 474         if (ide_lock_host(host, hwif))
 475                 return BLK_STS_DEV_RESOURCE;
 476
 477         blk_mq_start_request(rq);
 478
 479         spin_lock_irq(&hwif->lock);
 480
 481         if (!ide_lock_port(hwif)) {
 482                 ide_hwif_t *prev_port;
 483
 484                 WARN_ON_ONCE(hwif->rq);
 485 repeat:
 486                 prev_port = hwif->host->cur_port;
 487                 if (drive->dev_flags & IDE_DFLAG_SLEEPING &&
 488                     time_after(drive->sleep, jiffies)) {
 489                         ide_unlock_port(hwif);
 490                         goto plug_device;
 491                 }
 492
 493                 if ((hwif->host->host_flags & IDE_HFLAG_SERIALIZE) &&
 494                     hwif != prev_port) {
 495                         ide_drive_t *cur_dev =
 496                                 prev_port ? prev_port->cur_dev : NULL;
 497
 498                         /*
 499                          * set nIEN for previous port, drives in the
 500                          * quirk list may not like intr setups/cleanups
 501                          */
 502                         if (cur_dev &&
 503                             (cur_dev->dev_flags & IDE_DFLAG_NIEN_QUIRK) == 0)
 504                                 prev_port->tp_ops->write_devctl(prev_port,
 505                                                                 ATA_NIEN |
 506                                                                 ATA_DEVCTL_OBS);
 507
 508                         hwif->host->cur_port = hwif;
 509                 }
 510                 hwif->cur_dev = drive;
 511                 drive->dev_flags &= ~(IDE_DFLAG_SLEEPING | IDE_DFLAG_PARKED);
 512
 513                 /*
 514                  * we know that the queue isn't empty, but this can happen
 515                  * if ->prep_rq() decides to kill a request
 516                  */
 517                 if (!rq) {
 518                         rq = bd->rq;
 519                         if (!rq) {
 520                                 ide_unlock_port(hwif);
 521                                 goto out;
 522                         }
 523                 }
 524
 525                 /*
 526                  * Sanity: don't accept a request that isn't a PM request
 527                  * if we are currently power managed. This is very important as
 528                  * blk_stop_queue() doesn't prevent the blk_fetch_request()
 529                  * above to return us whatever is in the queue. Since we call
 530                  * ide_do_request() ourselves, we end up taking requests while
 531                  * the queue is blocked...
 532                  *
 533                  * We let requests forced at head of queue with ide-preempt
 534                  * though. I hope that doesn't happen too much, hopefully not
 535                  * unless the subdriver triggers such a thing in its own PM
 536                  * state machine.
 537                  */
 538                 if ((drive->dev_flags & IDE_DFLAG_BLOCKED) &&
 539                     ata_pm_request(rq) == 0 &&
 540                     (rq->rq_flags & RQF_PREEMPT) == 0) {
 541                         /* there should be no pending command at this point */
 542                         ide_unlock_port(hwif);
 543                         goto plug_device;
 544                 }
 545
 546                 scsi_req(rq)->resid_len = blk_rq_bytes(rq);
 547                 hwif->rq = rq;
 548
 549                 spin_unlock_irq(&hwif->lock);
 550                 startstop = start_request(drive, rq);
 551                 spin_lock_irq(&hwif->lock);
 552
 553                 if (startstop == ide_stopped) {
 554                         rq = hwif->rq;
 555                         hwif->rq = NULL;
 556                         if (rq)
 557                                 goto repeat;
 558                         ide_unlock_port(hwif);
 559                         goto out;
 560                 }
 561         } else {
 562 plug_device:
 563                 spin_unlock_irq(&hwif->lock);
 564                 ide_unlock_host(host);
 565                 ide_requeue_and_plug(drive, rq);
 566                 return BLK_STS_OK;
 567         }
 568
 569 out:
 570         spin_unlock_irq(&hwif->lock);
 571         if (rq == NULL)
 572                 ide_unlock_host(host);
 573         return BLK_STS_OK;
 574 }
 575
 576 static int drive_is_ready(ide_drive_t *drive)
 577 {
 578         ide_hwif_t *hwif = drive->hwif;
 579         u8 stat = 0;
 580
 581         if (drive->waiting_for_dma)
 582                 return hwif->dma_ops->dma_test_irq(drive);
 583
 584         if (hwif->io_ports.ctl_addr &&
 585             (hwif->host_flags & IDE_HFLAG_BROKEN_ALTSTATUS) == 0)
 586                 stat = hwif->tp_ops->read_altstatus(hwif);
 587         else
 588                 /* Note: this may clear a pending IRQ!! */
 589                 stat = hwif->tp_ops->read_status(hwif);
 590
 591         if (stat & ATA_BUSY)
 592                 /* drive busy: definitely not interrupting */
 593                 return 0;
 594
 595         /* drive ready: *might* be interrupting */
 596         return 1;
 597 }
 598
 599 /**
 600  *      ide_timer_expiry        -       handle lack of an IDE interrupt
 601  *      @data: timer callback magic (hwif)
 602  *
 603  *      An IDE command has timed out before the expected drive return
 604  *      occurred. At this point we attempt to clean up the current
 605  *      mess. If the current handler includes an expiry handler then
 606  *      we invoke the expiry handler, and providing it is happy the
 607  *      work is done. If that fails we apply generic recovery rules
 608  *      invoking the handler and checking the drive DMA status. We
 609  *      have an excessively incestuous relationship with the DMA
 610  *      logic that wants cleaning up.
 611  */
 612
 613 void ide_timer_expiry (struct timer_list *t)
 614 {
 615         ide_hwif_t      *hwif = from_timer(hwif, t, timer);
 616         ide_drive_t     *uninitialized_var(drive);
 617         ide_handler_t   *handler;
 618         unsigned long   flags;
 619         int             wait = -1;
 620         int             plug_device = 0;
 621         struct request  *uninitialized_var(rq_in_flight);
 622
 623         spin_lock_irqsave(&hwif->lock, flags);
 624
 625         handler = hwif->handler;
 626
 627         if (handler == NULL || hwif->req_gen != hwif->req_gen_timer) {
 628                 /*
 629                  * Either a marginal timeout occurred
 630                  * (got the interrupt just as timer expired),
 631                  * or we were "sleeping" to give other devices a chance.
 632                  * Either way, we don't really want to complain about anything.
 633                  */
 634         } else {
 635                 ide_expiry_t *expiry = hwif->expiry;
 636                 ide_startstop_t startstop = ide_stopped;
 637
 638                 drive = hwif->cur_dev;
 639
 640                 if (expiry) {
 641                         wait = expiry(drive);
 642                         if (wait > 0) { /* continue */
 643                                 /* reset timer */
 644                                 hwif->timer.expires = jiffies + wait;
 645                                 hwif->req_gen_timer = hwif->req_gen;
 646                                 add_timer(&hwif->timer);
 647                                 spin_unlock_irqrestore(&hwif->lock, flags);
 648                                 return;
 649                         }
 650                 }
 651                 hwif->handler = NULL;
 652                 hwif->expiry = NULL;
 653                 /*
 654                  * We need to simulate a real interrupt when invoking
 655                  * the handler() function, which means we need to
 656                  * globally mask the specific IRQ:
 657                  */
 658                 spin_unlock(&hwif->lock);
 659                 /* disable_irq_nosync ?? */
 660                 disable_irq(hwif->irq);
 661
 662                 if (hwif->polling) {
 663                         startstop = handler(drive);
 664                 } else if (drive_is_ready(drive)) {
 665                         if (drive->waiting_for_dma)
 666                                 hwif->dma_ops->dma_lost_irq(drive);
 667                         if (hwif->port_ops && hwif->port_ops->clear_irq)
 668                                 hwif->port_ops->clear_irq(drive);
 669
 670                         printk(KERN_WARNING "%s: lost interrupt\n",
 671                                 drive->name);
 672                         startstop = handler(drive);
 673                 } else {
 674                         if (drive->waiting_for_dma)
 675                                 startstop = ide_dma_timeout_retry(drive, wait);
 676                         else
 677                                 startstop = ide_error(drive, "irq timeout",
 678                                         hwif->tp_ops->read_status(hwif));
 679                 }
 680                 /* Disable interrupts again, `handler' might have enabled it */
 681                 spin_lock_irq(&hwif->lock);
 682                 enable_irq(hwif->irq);
 683                 if (startstop == ide_stopped && hwif->polling == 0) {
 684                         rq_in_flight = hwif->rq;
 685                         hwif->rq = NULL;
 686                         ide_unlock_port(hwif);
 687                         plug_device = 1;
 688                 }
 689         }
 690         spin_unlock_irqrestore(&hwif->lock, flags);
 691
 692         if (plug_device) {
 693                 ide_unlock_host(hwif->host);
 694                 ide_requeue_and_plug(drive, rq_in_flight);
 695         }
 696 }
 697
 698 /**
 699  *      unexpected_intr         -       handle an unexpected IDE interrupt
 700  *      @irq: interrupt line
 701  *      @hwif: port being processed
 702  *
 703  *      There's nothing really useful we can do with an unexpected interrupt,
 704  *      other than reading the status register (to clear it), and logging it.
 705  *      There should be no way that an irq can happen before we're ready for it,
 706  *      so we needn't worry much about losing an "important" interrupt here.
 707  *
 708  *      On laptops (and "green" PCs), an unexpected interrupt occurs whenever
 709  *      the drive enters "idle", "standby", or "sleep" mode, so if the status
 710  *      looks "good", we just ignore the interrupt completely.
 711  *
 712  *      This routine assumes __cli() is in effect when called.
 713  *
 714  *      If an unexpected interrupt happens on irq15 while we are handling irq14
 715  *      and if the two interfaces are "serialized" (CMD640), then it looks like
 716  *      we could screw up by interfering with a new request being set up for
 717  *      irq15.
 718  *
 719  *      In reality, this is a non-issue.  The new command is not sent unless
 720  *      the drive is ready to accept one, in which case we know the drive is
 721  *      not trying to interrupt us.  And ide_set_handler() is always invoked
 722  *      before completing the issuance of any new drive command, so we will not
 723  *      be accidentally invoked as a result of any valid command completion
 724  *      interrupt.
 725  */
 726
 727 static void unexpected_intr(int irq, ide_hwif_t *hwif)
 728 {
 729         u8 stat = hwif->tp_ops->read_status(hwif);
 730
 731         if (!OK_STAT(stat, ATA_DRDY, BAD_STAT)) {
 732                 /* Try to not flood the console with msgs */
 733                 static unsigned long last_msgtime, count;
 734                 ++count;
 735
 736                 if (time_after(jiffies, last_msgtime + HZ)) {
 737                         last_msgtime = jiffies;
 738                         printk(KERN_ERR "%s: unexpected interrupt, "
 739                                 "status=0x%02x, count=%ld\n",
 740                                 hwif->name, stat, count);
 741                 }
 742         }
 743 }
 744
 745 /**
 746  *      ide_intr        -       default IDE interrupt handler
 747  *      @irq: interrupt number
 748  *      @dev_id: hwif
 749  *      @regs: unused weirdness from the kernel irq layer
 750  *
 751  *      This is the default IRQ handler for the IDE layer. You should
 752  *      not need to override it. If you do be aware it is subtle in
 753  *      places
 754  *
 755  *      hwif is the interface in the group currently performing
 756  *      a command. hwif->cur_dev is the drive and hwif->handler is
 757  *      the IRQ handler to call. As we issue a command the handlers
 758  *      step through multiple states, reassigning the handler to the
 759  *      next step in the process. Unlike a smart SCSI controller IDE
 760  *      expects the main processor to sequence the various transfer
 761  *      stages. We also manage a poll timer to catch up with most
 762  *      timeout situations. There are still a few where the handlers
 763  *      don't ever decide to give up.
 764  *
 765  *      The handler eventually returns ide_stopped to indicate the
 766  *      request completed. At this point we issue the next request
 767  *      on the port and the process begins again.
 768  */
 769
 770 irqreturn_t ide_intr (int irq, void *dev_id)
 771 {
 772         ide_hwif_t *hwif = (ide_hwif_t *)dev_id;
 773         struct ide_host *host = hwif->host;
 774         ide_drive_t *uninitialized_var(drive);
 775         ide_handler_t *handler;
 776         unsigned long flags;
 777         ide_startstop_t startstop;
 778         irqreturn_t irq_ret = IRQ_NONE;
 779         int plug_device = 0;
 780         struct request *uninitialized_var(rq_in_flight);
 781
 782         if (host->host_flags & IDE_HFLAG_SERIALIZE) {
 783                 if (hwif != host->cur_port)
 784                         goto out_early;
 785         }
 786
 787         spin_lock_irqsave(&hwif->lock, flags);
 788
 789         if (hwif->port_ops && hwif->port_ops->test_irq &&
 790             hwif->port_ops->test_irq(hwif) == 0)
 791                 goto out;
 792
 793         handler = hwif->handler;
 794
 795         if (handler == NULL || hwif->polling) {
 796                 /*
 797                  * Not expecting an interrupt from this drive.
 798                  * That means this could be:
 799                  *      (1) an interrupt from another PCI device
 800                  *      sharing the same PCI INT# as us.
 801                  * or   (2) a drive just entered sleep or standby mode,
 802                  *      and is interrupting to let us know.
 803                  * or   (3) a spurious interrupt of unknown origin.
 804                  *
 805                  * For PCI, we cannot tell the difference,
 806                  * so in that case we just ignore it and hope it goes away.
 807                  */
 808                 if ((host->irq_flags & IRQF_SHARED) == 0) {
 809                         /*
 810                          * Probably not a shared PCI interrupt,
 811                          * so we can safely try to do something about it:
 812                          */
 813                         unexpected_intr(irq, hwif);
 814                 } else {
 815                         /*
 816                          * Whack the status register, just in case
 817                          * we have a leftover pending IRQ.
 818                          */
 819                         (void)hwif->tp_ops->read_status(hwif);
 820                 }
 821                 goto out;
 822         }
 823
 824         drive = hwif->cur_dev;
 825
 826         if (!drive_is_ready(drive))
 827                 /*
 828                  * This happens regularly when we share a PCI IRQ with
 829                  * another device.  Unfortunately, it can also happen
 830                  * with some buggy drives that trigger the IRQ before
 831                  * their status register is up to date.  Hopefully we have
 832                  * enough advance overhead that the latter isn't a problem.
 833                  */
 834                 goto out;
 835
 836         hwif->handler = NULL;
 837         hwif->expiry = NULL;
 838         hwif->req_gen++;
 839         del_timer(&hwif->timer);
 840         spin_unlock(&hwif->lock);
 841
 842         if (hwif->port_ops && hwif->port_ops->clear_irq)
 843                 hwif->port_ops->clear_irq(drive);
 844
 845         if (drive->dev_flags & IDE_DFLAG_UNMASK)
 846                 local_irq_enable_in_hardirq();
 847
 848         /* service this interrupt, may set handler for next interrupt */
 849         startstop = handler(drive);
 850
 851         spin_lock_irq(&hwif->lock);
 852         /*
 853          * Note that handler() may have set things up for another
 854          * interrupt to occur soon, but it cannot happen until
 855          * we exit from this routine, because it will be the
 856          * same irq as is currently being serviced here, and Linux
 857          * won't allow another of the same (on any CPU) until we return.
 858          */
 859         if (startstop == ide_stopped && hwif->polling == 0) {
 860                 BUG_ON(hwif->handler);
 861                 rq_in_flight = hwif->rq;
 862                 hwif->rq = NULL;
 863                 ide_unlock_port(hwif);
 864                 plug_device = 1;
 865         }
 866         irq_ret = IRQ_HANDLED;
 867 out:
 868         spin_unlock_irqrestore(&hwif->lock, flags);
 869 out_early:
 870         if (plug_device) {
 871                 ide_unlock_host(hwif->host);
 872                 ide_requeue_and_plug(drive, rq_in_flight);
 873         }
 874
 875         return irq_ret;
 876 }
 877 EXPORT_SYMBOL_GPL(ide_intr);
 878
 879 void ide_pad_transfer(ide_drive_t *drive, int write, int len)
 880 {
 881         ide_hwif_t *hwif = drive->hwif;
 882         u8 buf[4] = { 0 };
 883
 884         while (len > 0) {
 885                 if (write)
 886                         hwif->tp_ops->output_data(drive, NULL, buf, min(4, len));
 887                 else
 888                         hwif->tp_ops->input_data(drive, NULL, buf, min(4, len));
 889                 len -= 4;
 890         }
 891 }
 892 EXPORT_SYMBOL_GPL(ide_pad_transfer);
 893
 894 void ide_insert_request_head(ide_drive_t *drive, struct request *rq)
 895 {
 896         ide_hwif_t *hwif = drive->hwif;
 897         unsigned long flags;
 898
 899         spin_lock_irqsave(&hwif->lock, flags);
 900         list_add_tail(&rq->queuelist, &drive->rq_list);
 901         spin_unlock_irqrestore(&hwif->lock, flags);
 902
 903         kblockd_schedule_work(&drive->rq_work);
 904 }
 905 EXPORT_SYMBOL_GPL(ide_insert_request_head);