drivers/block/ub.c

   1 /*
   2  * The low performance USB storage driver (ub).
   3  *
   4  * Copyright (c) 1999, 2000 Matthew Dharm (mdharm-usb@one-eyed-alien.net)
   5  * Copyright (C) 2004 Pete Zaitcev (zaitcev@yahoo.com)
   6  *
   7  * This work is a part of Linux kernel, is derived from it,
   8  * and is not licensed separately. See file COPYING for details.
   9  *
  10  * TODO (sorted by decreasing priority)
  11  *  -- set readonly flag for CDs, set removable flag for CF readers
  12  *  -- do inquiry and verify we got a disk and not a tape (for LUN mismatch)
  13  *  -- verify the 13 conditions and do bulk resets
  14  *  -- highmem
  15  *  -- move top_sense and work_bcs into separate allocations (if they survive)
  16  *     for cache purists and esoteric architectures.
  17  *  -- Allocate structure for LUN 0 before the first ub_sync_tur, avoid NULL. ?
  18  *  -- prune comments, they are too volumnous
  19  *  -- Resove XXX's
  20  *  -- CLEAR, CLR2STS, CLRRS seem to be ripe for refactoring.
  21  */
  22 #include <linux/kernel.h>
  23 #include <linux/module.h>
  24 #include <linux/usb.h>
  25 #include <linux/usb_usual.h>
  26 #include <linux/blkdev.h>
  27 #include <linux/timer.h>
  28 #include <linux/scatterlist.h>
  29 #include <scsi/scsi.h>
  30
  31 #define DRV_NAME "ub"
  32
  33 #define UB_MAJOR 180
  34
  35 /*
  36  * The command state machine is the key model for understanding of this driver.
  37  *
  38  * The general rule is that all transitions are done towards the bottom
  39  * of the diagram, thus preventing any loops.
  40  *
  41  * An exception to that is how the STAT state is handled. A counter allows it
  42  * to be re-entered along the path marked with [C].
  43  *
  44  *       +--------+
  45  *       ! INIT   !
  46  *       +--------+
  47  *           !
  48  *        ub_scsi_cmd_start fails ->--------------------------------------\
  49  *           !                                                            !
  50  *           V                                                            !
  51  *       +--------+                                                       !
  52  *       ! CMD    !                                                       !
  53  *       +--------+                                                       !
  54  *           !                                            +--------+      !
  55  *         was -EPIPE -->-------------------------------->! CLEAR  !      !
  56  *           !                                            +--------+      !
  57  *           !                                                !           !
  58  *         was error -->------------------------------------- ! --------->\
  59  *           !                                                !           !
  60  *  /--<-- cmd->dir == NONE ?                                 !           !
  61  *  !        !                                                !           !
  62  *  !        V                                                !           !
  63  *  !    +--------+                                           !           !
  64  *  !    ! DATA   !                                           !           !
  65  *  !    +--------+                                           !           !
  66  *  !        !                           +---------+          !           !
  67  *  !      was -EPIPE -->--------------->! CLR2STS !          !           !
  68  *  !        !                           +---------+          !           !
  69  *  !        !                                !               !           !
  70  *  !        !                              was error -->---- ! --------->\
  71  *  !      was error -->--------------------- ! ------------- ! --------->\
  72  *  !        !                                !               !           !
  73  *  !        V                                !               !           !
  74  *  \--->+--------+                           !               !           !
  75  *       ! STAT   !<--------------------------/               !           !
  76  *  /--->+--------+                                           !           !
  77  *  !        !                                                !           !
  78  * [C]     was -EPIPE -->-----------\                         !           !
  79  *  !        !                      !                         !           !
  80  *  +<---- len == 0                 !                         !           !
  81  *  !        !                      !                         !           !
  82  *  !      was error -->--------------------------------------!---------->\
  83  *  !        !                      !                         !           !
  84  *  +<---- bad CSW                  !                         !           !
  85  *  +<---- bad tag                  !                         !           !
  86  *  !        !                      V                         !           !
  87  *  !        !                 +--------+                     !           !
  88  *  !        !                 ! CLRRS  !                     !           !
  89  *  !        !                 +--------+                     !           !
  90  *  !        !                      !                         !           !
  91  *  \------- ! --------------------[C]--------\               !           !
  92  *           !                                !               !           !
  93  *         cmd->error---\                +--------+           !           !
  94  *           !          +--------------->! SENSE  !<----------/           !
  95  *         STAT_FAIL----/                +--------+                       !
  96  *           !                                !                           V
  97  *           !                                V                      +--------+
  98  *           \--------------------------------\--------------------->! DONE   !
  99  *                                                                   +--------+
 100  */
 101
 102 /*
 103  * This many LUNs per USB device.
 104  * Every one of them takes a host, see UB_MAX_HOSTS.
 105  */
 106 #define UB_MAX_LUNS   9
 107
 108 /*
 109  */
 110
 111 #define UB_PARTS_PER_LUN      8
 112
 113 #define UB_MAX_CDB_SIZE      16         /* Corresponds to Bulk */
 114
 115 #define UB_SENSE_SIZE  18
 116
 117 /*
 118  */
 119
 120 /* command block wrapper */
 121 struct bulk_cb_wrap {
 122         __le32  Signature;              /* contains 'USBC' */
 123         u32     Tag;                    /* unique per command id */
 124         __le32  DataTransferLength;     /* size of data */
 125         u8      Flags;                  /* direction in bit 0 */
 126         u8      Lun;                    /* LUN */
 127         u8      Length;                 /* of of the CDB */
 128         u8      CDB[UB_MAX_CDB_SIZE];   /* max command */
 129 };
 130
 131 #define US_BULK_CB_WRAP_LEN     31
 132 #define US_BULK_CB_SIGN         0x43425355      /*spells out USBC */
 133 #define US_BULK_FLAG_IN         1
 134 #define US_BULK_FLAG_OUT        0
 135
 136 /* command status wrapper */
 137 struct bulk_cs_wrap {
 138         __le32  Signature;              /* should = 'USBS' */
 139         u32     Tag;                    /* same as original command */
 140         __le32  Residue;                /* amount not transferred */
 141         u8      Status;                 /* see below */
 142 };
 143
 144 #define US_BULK_CS_WRAP_LEN     13
 145 #define US_BULK_CS_SIGN         0x53425355      /* spells out 'USBS' */
 146 #define US_BULK_STAT_OK         0
 147 #define US_BULK_STAT_FAIL       1
 148 #define US_BULK_STAT_PHASE      2
 149
 150 /* bulk-only class specific requests */
 151 #define US_BULK_RESET_REQUEST   0xff
 152 #define US_BULK_GET_MAX_LUN     0xfe
 153
 154 /*
 155  */
 156 struct ub_dev;
 157
 158 #define UB_MAX_REQ_SG   9       /* cdrecord requires 32KB and maybe a header */
 159 #define UB_MAX_SECTORS 64
 160
 161 /*
 162  * A second is more than enough for a 32K transfer (UB_MAX_SECTORS)
 163  * even if a webcam hogs the bus, but some devices need time to spin up.
 164  */
 165 #define UB_URB_TIMEOUT  (HZ*2)
 166 #define UB_DATA_TIMEOUT (HZ*5)  /* ZIP does spin-ups in the data phase */
 167 #define UB_STAT_TIMEOUT (HZ*5)  /* Same spinups and eject for a dataless cmd. */
 168 #define UB_CTRL_TIMEOUT (HZ/2)  /* 500ms ought to be enough to clear a stall */
 169
 170 /*
 171  * An instance of a SCSI command in transit.
 172  */
 173 #define UB_DIR_NONE     0
 174 #define UB_DIR_READ     1
 175 #define UB_DIR_ILLEGAL2 2
 176 #define UB_DIR_WRITE    3
 177
 178 #define UB_DIR_CHAR(c)  (((c)==UB_DIR_WRITE)? 'w': \
 179                          (((c)==UB_DIR_READ)? 'r': 'n'))
 180
 181 enum ub_scsi_cmd_state {
 182         UB_CMDST_INIT,                  /* Initial state */
 183         UB_CMDST_CMD,                   /* Command submitted */
 184         UB_CMDST_DATA,                  /* Data phase */
 185         UB_CMDST_CLR2STS,               /* Clearing before requesting status */
 186         UB_CMDST_STAT,                  /* Status phase */
 187         UB_CMDST_CLEAR,                 /* Clearing a stall (halt, actually) */
 188         UB_CMDST_CLRRS,                 /* Clearing before retrying status */
 189         UB_CMDST_SENSE,                 /* Sending Request Sense */
 190         UB_CMDST_DONE                   /* Final state */
 191 };
 192
 193 struct ub_scsi_cmd {
 194         unsigned char cdb[UB_MAX_CDB_SIZE];
 195         unsigned char cdb_len;
 196
 197         unsigned char dir;              /* 0 - none, 1 - read, 3 - write. */
 198         enum ub_scsi_cmd_state state;
 199         unsigned int tag;
 200         struct ub_scsi_cmd *next;
 201
 202         int error;                      /* Return code - valid upon done */
 203         unsigned int act_len;           /* Return size */
 204         unsigned char key, asc, ascq;   /* May be valid if error==-EIO */
 205
 206         int stat_count;                 /* Retries getting status. */
 207
 208         unsigned int len;               /* Requested length */
 209         unsigned int current_sg;
 210         unsigned int nsg;               /* sgv[nsg] */
 211         struct scatterlist sgv[UB_MAX_REQ_SG];
 212
 213         struct ub_lun *lun;
 214         void (*done)(struct ub_dev *, struct ub_scsi_cmd *);
 215         void *back;
 216 };
 217
 218 struct ub_request {
 219         struct request *rq;
 220         unsigned int current_try;
 221         unsigned int nsg;               /* sgv[nsg] */
 222         struct scatterlist sgv[UB_MAX_REQ_SG];
 223 };
 224
 225 /*
 226  */
 227 struct ub_capacity {
 228         unsigned long nsec;             /* Linux size - 512 byte sectors */
 229         unsigned int bsize;             /* Linux hardsect_size */
 230         unsigned int bshift;            /* Shift between 512 and hard sects */
 231 };
 232
 233 /*
 234  * This is a direct take-off from linux/include/completion.h
 235  * The difference is that I do not wait on this thing, just poll.
 236  * When I want to wait (ub_probe), I just use the stock completion.
 237  *
 238  * Note that INIT_COMPLETION takes no lock. It is correct. But why
 239  * in the bloody hell that thing takes struct instead of pointer to struct
 240  * is quite beyond me. I just copied it from the stock completion.
 241  */
 242 struct ub_completion {
 243         unsigned int done;
 244         spinlock_t lock;
 245 };
 246
 247 static inline void ub_init_completion(struct ub_completion *x)
 248 {
 249         x->done = 0;
 250         spin_lock_init(&x->lock);
 251 }
 252
 253 #define UB_INIT_COMPLETION(x)   ((x).done = 0)
 254
 255 static void ub_complete(struct ub_completion *x)
 256 {
 257         unsigned long flags;
 258
 259         spin_lock_irqsave(&x->lock, flags);
 260         x->done++;
 261         spin_unlock_irqrestore(&x->lock, flags);
 262 }
 263
 264 static int ub_is_completed(struct ub_completion *x)
 265 {
 266         unsigned long flags;
 267         int ret;
 268
 269         spin_lock_irqsave(&x->lock, flags);
 270         ret = x->done;
 271         spin_unlock_irqrestore(&x->lock, flags);
 272         return ret;
 273 }
 274
 275 /*
 276  */
 277 struct ub_scsi_cmd_queue {
 278         int qlen, qmax;
 279         struct ub_scsi_cmd *head, *tail;
 280 };
 281
 282 /*
 283  * The block device instance (one per LUN).
 284  */
 285 struct ub_lun {
 286         struct ub_dev *udev;
 287         struct list_head link;
 288         struct gendisk *disk;
 289         int id;                         /* Host index */
 290         int num;                        /* LUN number */
 291         char name[16];
 292
 293         int changed;                    /* Media was changed */
 294         int removable;
 295         int readonly;
 296
 297         struct ub_request urq;
 298
 299         /* Use Ingo's mempool if or when we have more than one command. */
 300         /*
 301          * Currently we never need more than one command for the whole device.
 302          * However, giving every LUN a command is a cheap and automatic way
 303          * to enforce fairness between them.
 304          */
 305         int cmda[1];
 306         struct ub_scsi_cmd cmdv[1];
 307
 308         struct ub_capacity capacity;
 309 };
 310
 311 /*
 312  * The USB device instance.
 313  */
 314 struct ub_dev {
 315         spinlock_t *lock;
 316         atomic_t poison;                /* The USB device is disconnected */
 317         int openc;                      /* protected by ub_lock! */
 318                                         /* kref is too implicit for our taste */
 319         int reset;                      /* Reset is running */
 320         unsigned int tagcnt;
 321         char name[12];
 322         struct usb_device *dev;
 323         struct usb_interface *intf;
 324
 325         struct list_head luns;
 326
 327         unsigned int send_bulk_pipe;    /* cached pipe values */
 328         unsigned int recv_bulk_pipe;
 329         unsigned int send_ctrl_pipe;
 330         unsigned int recv_ctrl_pipe;
 331
 332         struct tasklet_struct tasklet;
 333
 334         struct ub_scsi_cmd_queue cmd_queue;
 335         struct ub_scsi_cmd top_rqs_cmd; /* REQUEST SENSE */
 336         unsigned char top_sense[UB_SENSE_SIZE];
 337
 338         struct ub_completion work_done;
 339         struct urb work_urb;
 340         struct timer_list work_timer;
 341         int last_pipe;                  /* What might need clearing */
 342         __le32 signature;               /* Learned signature */
 343         struct bulk_cb_wrap work_bcb;
 344         struct bulk_cs_wrap work_bcs;
 345         struct usb_ctrlrequest work_cr;
 346
 347         struct work_struct reset_work;
 348         wait_queue_head_t reset_wait;
 349
 350         int sg_stat[6];
 351 };
 352
 353 /*
 354  */
 355 static void ub_cleanup(struct ub_dev *sc);
 356 static int ub_request_fn_1(struct ub_lun *lun, struct request *rq);
 357 static void ub_cmd_build_block(struct ub_dev *sc, struct ub_lun *lun,
 358     struct ub_scsi_cmd *cmd, struct ub_request *urq);
 359 static void ub_cmd_build_packet(struct ub_dev *sc, struct ub_lun *lun,
 360     struct ub_scsi_cmd *cmd, struct ub_request *urq);
 361 static void ub_rw_cmd_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 362 static void ub_end_rq(struct request *rq, unsigned int status);
 363 static int ub_rw_cmd_retry(struct ub_dev *sc, struct ub_lun *lun,
 364     struct ub_request *urq, struct ub_scsi_cmd *cmd);
 365 static int ub_submit_scsi(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 366 static void ub_urb_complete(struct urb *urb);
 367 static void ub_scsi_action(unsigned long _dev);
 368 static void ub_scsi_dispatch(struct ub_dev *sc);
 369 static void ub_scsi_urb_compl(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 370 static void ub_data_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 371 static void ub_state_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd, int rc);
 372 static int __ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 373 static void ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 374 static void ub_state_stat_counted(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 375 static void ub_state_sense(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 376 static int ub_submit_clear_stall(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
 377     int stalled_pipe);
 378 static void ub_top_sense_done(struct ub_dev *sc, struct ub_scsi_cmd *scmd);
 379 static void ub_reset_enter(struct ub_dev *sc, int try);
 380 static void ub_reset_task(struct work_struct *work);
 381 static int ub_sync_tur(struct ub_dev *sc, struct ub_lun *lun);
 382 static int ub_sync_read_cap(struct ub_dev *sc, struct ub_lun *lun,
 383     struct ub_capacity *ret);
 384 static int ub_sync_reset(struct ub_dev *sc);
 385 static int ub_probe_clear_stall(struct ub_dev *sc, int stalled_pipe);
 386 static int ub_probe_lun(struct ub_dev *sc, int lnum);
 387
 388 /*
 389  */
 390 #ifdef CONFIG_USB_LIBUSUAL
 391
 392 #define ub_usb_ids  storage_usb_ids
 393 #else
 394
 395 static struct usb_device_id ub_usb_ids[] = {
 396         { USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, US_SC_SCSI, US_PR_BULK) },
 397         { }
 398 };
 399
 400 MODULE_DEVICE_TABLE(usb, ub_usb_ids);
 401 #endif /* CONFIG_USB_LIBUSUAL */
 402
 403 /*
 404  * Find me a way to identify "next free minor" for add_disk(),
 405  * and the array disappears the next day. However, the number of
 406  * hosts has something to do with the naming and /proc/partitions.
 407  * This has to be thought out in detail before changing.
 408  * If UB_MAX_HOST was 1000, we'd use a bitmap. Or a better data structure.
 409  */
 410 #define UB_MAX_HOSTS  26
 411 static char ub_hostv[UB_MAX_HOSTS];
 412
 413 #define UB_QLOCK_NUM 5
 414 static spinlock_t ub_qlockv[UB_QLOCK_NUM];
 415 static int ub_qlock_next = 0;
 416
 417 static DEFINE_SPINLOCK(ub_lock);        /* Locks globals and ->openc */
 418
 419 /*
 420  * The id allocator.
 421  *
 422  * This also stores the host for indexing by minor, which is somewhat dirty.
 423  */
 424 static int ub_id_get(void)
 425 {
 426         unsigned long flags;
 427         int i;
 428
 429         spin_lock_irqsave(&ub_lock, flags);
 430         for (i = 0; i < UB_MAX_HOSTS; i++) {
 431                 if (ub_hostv[i] == 0) {
 432                         ub_hostv[i] = 1;
 433                         spin_unlock_irqrestore(&ub_lock, flags);
 434                         return i;
 435                 }
 436         }
 437         spin_unlock_irqrestore(&ub_lock, flags);
 438         return -1;
 439 }
 440
 441 static void ub_id_put(int id)
 442 {
 443         unsigned long flags;
 444
 445         if (id < 0 || id >= UB_MAX_HOSTS) {
 446                 printk(KERN_ERR DRV_NAME ": bad host ID %d\n", id);
 447                 return;
 448         }
 449
 450         spin_lock_irqsave(&ub_lock, flags);
 451         if (ub_hostv[id] == 0) {
 452                 spin_unlock_irqrestore(&ub_lock, flags);
 453                 printk(KERN_ERR DRV_NAME ": freeing free host ID %d\n", id);
 454                 return;
 455         }
 456         ub_hostv[id] = 0;
 457         spin_unlock_irqrestore(&ub_lock, flags);
 458 }
 459
 460 /*
 461  * This is necessitated by the fact that blk_cleanup_queue does not
 462  * necesserily destroy the queue. Instead, it may merely decrease q->refcnt.
 463  * Since our blk_init_queue() passes a spinlock common with ub_dev,
 464  * we have life time issues when ub_cleanup frees ub_dev.
 465  */
 466 static spinlock_t *ub_next_lock(void)
 467 {
 468         unsigned long flags;
 469         spinlock_t *ret;
 470
 471         spin_lock_irqsave(&ub_lock, flags);
 472         ret = &ub_qlockv[ub_qlock_next];
 473         ub_qlock_next = (ub_qlock_next + 1) % UB_QLOCK_NUM;
 474         spin_unlock_irqrestore(&ub_lock, flags);
 475         return ret;
 476 }
 477
 478 /*
 479  * Downcount for deallocation. This rides on two assumptions:
 480  *  - once something is poisoned, its refcount cannot grow
 481  *  - opens cannot happen at this time (del_gendisk was done)
 482  * If the above is true, we can drop the lock, which we need for
 483  * blk_cleanup_queue(): the silly thing may attempt to sleep.
 484  * [Actually, it never needs to sleep for us, but it calls might_sleep()]
 485  */
 486 static void ub_put(struct ub_dev *sc)
 487 {
 488         unsigned long flags;
 489
 490         spin_lock_irqsave(&ub_lock, flags);
 491         --sc->openc;
 492         if (sc->openc == 0 && atomic_read(&sc->poison)) {
 493                 spin_unlock_irqrestore(&ub_lock, flags);
 494                 ub_cleanup(sc);
 495         } else {
 496                 spin_unlock_irqrestore(&ub_lock, flags);
 497         }
 498 }
 499
 500 /*
 501  * Final cleanup and deallocation.
 502  */
 503 static void ub_cleanup(struct ub_dev *sc)
 504 {
 505         struct list_head *p;
 506         struct ub_lun *lun;
 507         struct request_queue *q;
 508
 509         while (!list_empty(&sc->luns)) {
 510                 p = sc->luns.next;
 511                 lun = list_entry(p, struct ub_lun, link);
 512                 list_del(p);
 513
 514                 /* I don't think queue can be NULL. But... Stolen from sx8.c */
 515                 if ((q = lun->disk->queue) != NULL)
 516                         blk_cleanup_queue(q);
 517                 /*
 518                  * If we zero disk->private_data BEFORE put_disk, we have
 519                  * to check for NULL all over the place in open, release,
 520                  * check_media and revalidate, because the block level
 521                  * semaphore is well inside the put_disk.
 522                  * But we cannot zero after the call, because *disk is gone.
 523                  * The sd.c is blatantly racy in this area.
 524                  */
 525                 /* disk->private_data = NULL; */
 526                 put_disk(lun->disk);
 527                 lun->disk = NULL;
 528
 529                 ub_id_put(lun->id);
 530                 kfree(lun);
 531         }
 532
 533         usb_set_intfdata(sc->intf, NULL);
 534         usb_put_intf(sc->intf);
 535         usb_put_dev(sc->dev);
 536         kfree(sc);
 537 }
 538
 539 /*
 540  * The "command allocator".
 541  */
 542 static struct ub_scsi_cmd *ub_get_cmd(struct ub_lun *lun)
 543 {
 544         struct ub_scsi_cmd *ret;
 545
 546         if (lun->cmda[0])
 547                 return NULL;
 548         ret = &lun->cmdv[0];
 549         lun->cmda[0] = 1;
 550         return ret;
 551 }
 552
 553 static void ub_put_cmd(struct ub_lun *lun, struct ub_scsi_cmd *cmd)
 554 {
 555         if (cmd != &lun->cmdv[0]) {
 556                 printk(KERN_WARNING "%s: releasing a foreign cmd %p\n",
 557                     lun->name, cmd);
 558                 return;
 559         }
 560         if (!lun->cmda[0]) {
 561                 printk(KERN_WARNING "%s: releasing a free cmd\n", lun->name);
 562                 return;
 563         }
 564         lun->cmda[0] = 0;
 565 }
 566
 567 /*
 568  * The command queue.
 569  */
 570 static void ub_cmdq_add(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 571 {
 572         struct ub_scsi_cmd_queue *t = &sc->cmd_queue;
 573
 574         if (t->qlen++ == 0) {
 575                 t->head = cmd;
 576                 t->tail = cmd;
 577         } else {
 578                 t->tail->next = cmd;
 579                 t->tail = cmd;
 580         }
 581
 582         if (t->qlen > t->qmax)
 583                 t->qmax = t->qlen;
 584 }
 585
 586 static void ub_cmdq_insert(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 587 {
 588         struct ub_scsi_cmd_queue *t = &sc->cmd_queue;
 589
 590         if (t->qlen++ == 0) {
 591                 t->head = cmd;
 592                 t->tail = cmd;
 593         } else {
 594                 cmd->next = t->head;
 595                 t->head = cmd;
 596         }
 597
 598         if (t->qlen > t->qmax)
 599                 t->qmax = t->qlen;
 600 }
 601
 602 static struct ub_scsi_cmd *ub_cmdq_pop(struct ub_dev *sc)
 603 {
 604         struct ub_scsi_cmd_queue *t = &sc->cmd_queue;
 605         struct ub_scsi_cmd *cmd;
 606
 607         if (t->qlen == 0)
 608                 return NULL;
 609         if (--t->qlen == 0)
 610                 t->tail = NULL;
 611         cmd = t->head;
 612         t->head = cmd->next;
 613         cmd->next = NULL;
 614         return cmd;
 615 }
 616
 617 #define ub_cmdq_peek(sc)  ((sc)->cmd_queue.head)
 618
 619 /*
 620  * The request function is our main entry point
 621  */
 622
 623 static void ub_request_fn(struct request_queue *q)
 624 {
 625         struct ub_lun *lun = q->queuedata;
 626         struct request *rq;
 627
 628         while ((rq = elv_next_request(q)) != NULL) {
 629                 if (ub_request_fn_1(lun, rq) != 0) {
 630                         blk_stop_queue(q);
 631                         break;
 632                 }
 633         }
 634 }
 635
 636 static int ub_request_fn_1(struct ub_lun *lun, struct request *rq)
 637 {
 638         struct ub_dev *sc = lun->udev;
 639         struct ub_scsi_cmd *cmd;
 640         struct ub_request *urq;
 641         int n_elem;
 642
 643         if (atomic_read(&sc->poison)) {
 644                 blkdev_dequeue_request(rq);
 645                 ub_end_rq(rq, DID_NO_CONNECT << 16);
 646                 return 0;
 647         }
 648
 649         if (lun->changed && !blk_pc_request(rq)) {
 650                 blkdev_dequeue_request(rq);
 651                 ub_end_rq(rq, SAM_STAT_CHECK_CONDITION);
 652                 return 0;
 653         }
 654
 655         if (lun->urq.rq != NULL)
 656                 return -1;
 657         if ((cmd = ub_get_cmd(lun)) == NULL)
 658                 return -1;
 659         memset(cmd, 0, sizeof(struct ub_scsi_cmd));
 660
 661         blkdev_dequeue_request(rq);
 662
 663         urq = &lun->urq;
 664         memset(urq, 0, sizeof(struct ub_request));
 665         urq->rq = rq;
 666
 667         /*
 668          * get scatterlist from block layer
 669          */
 670         sg_init_table(&urq->sgv[0], UB_MAX_REQ_SG);
 671         n_elem = blk_rq_map_sg(lun->disk->queue, rq, &urq->sgv[0]);
 672         if (n_elem < 0) {
 673                 /* Impossible, because blk_rq_map_sg should not hit ENOMEM. */
 674                 printk(KERN_INFO "%s: failed request map (%d)\n",
 675                     lun->name, n_elem);
 676                 goto drop;
 677         }
 678         if (n_elem > UB_MAX_REQ_SG) {   /* Paranoia */
 679                 printk(KERN_WARNING "%s: request with %d segments\n",
 680                     lun->name, n_elem);
 681                 goto drop;
 682         }
 683         urq->nsg = n_elem;
 684         sc->sg_stat[n_elem < 5 ? n_elem : 5]++;
 685
 686         if (blk_pc_request(rq)) {
 687                 ub_cmd_build_packet(sc, lun, cmd, urq);
 688         } else {
 689                 ub_cmd_build_block(sc, lun, cmd, urq);
 690         }
 691         cmd->state = UB_CMDST_INIT;
 692         cmd->lun = lun;
 693         cmd->done = ub_rw_cmd_done;
 694         cmd->back = urq;
 695
 696         cmd->tag = sc->tagcnt++;
 697         if (ub_submit_scsi(sc, cmd) != 0)
 698                 goto drop;
 699
 700         return 0;
 701
 702 drop:
 703         ub_put_cmd(lun, cmd);
 704         ub_end_rq(rq, DID_ERROR << 16);
 705         return 0;
 706 }
 707
 708 static void ub_cmd_build_block(struct ub_dev *sc, struct ub_lun *lun,
 709     struct ub_scsi_cmd *cmd, struct ub_request *urq)
 710 {
 711         struct request *rq = urq->rq;
 712         unsigned int block, nblks;
 713
 714         if (rq_data_dir(rq) == WRITE)
 715                 cmd->dir = UB_DIR_WRITE;
 716         else
 717                 cmd->dir = UB_DIR_READ;
 718
 719         cmd->nsg = urq->nsg;
 720         memcpy(cmd->sgv, urq->sgv, sizeof(struct scatterlist) * cmd->nsg);
 721
 722         /*
 723          * build the command
 724          *
 725          * The call to blk_queue_hardsect_size() guarantees that request
 726          * is aligned, but it is given in terms of 512 byte units, always.
 727          */
 728         block = rq->sector >> lun->capacity.bshift;
 729         nblks = rq->nr_sectors >> lun->capacity.bshift;
 730
 731         cmd->cdb[0] = (cmd->dir == UB_DIR_READ)? READ_10: WRITE_10;
 732         /* 10-byte uses 4 bytes of LBA: 2147483648KB, 2097152MB, 2048GB */
 733         cmd->cdb[2] = block >> 24;
 734         cmd->cdb[3] = block >> 16;
 735         cmd->cdb[4] = block >> 8;
 736         cmd->cdb[5] = block;
 737         cmd->cdb[7] = nblks >> 8;
 738         cmd->cdb[8] = nblks;
 739         cmd->cdb_len = 10;
 740
 741         cmd->len = rq->nr_sectors * 512;
 742 }
 743
 744 static void ub_cmd_build_packet(struct ub_dev *sc, struct ub_lun *lun,
 745     struct ub_scsi_cmd *cmd, struct ub_request *urq)
 746 {
 747         struct request *rq = urq->rq;
 748
 749         if (rq->data_len == 0) {
 750                 cmd->dir = UB_DIR_NONE;
 751         } else {
 752                 if (rq_data_dir(rq) == WRITE)
 753                         cmd->dir = UB_DIR_WRITE;
 754                 else
 755                         cmd->dir = UB_DIR_READ;
 756         }
 757
 758         cmd->nsg = urq->nsg;
 759         memcpy(cmd->sgv, urq->sgv, sizeof(struct scatterlist) * cmd->nsg);
 760
 761         memcpy(&cmd->cdb, rq->cmd, rq->cmd_len);
 762         cmd->cdb_len = rq->cmd_len;
 763
 764         cmd->len = rq->data_len;
 765 }
 766
 767 static void ub_rw_cmd_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 768 {
 769         struct ub_lun *lun = cmd->lun;
 770         struct ub_request *urq = cmd->back;
 771         struct request *rq;
 772         unsigned int scsi_status;
 773
 774         rq = urq->rq;
 775
 776         if (cmd->error == 0) {
 777                 if (blk_pc_request(rq)) {
 778                         if (cmd->act_len >= rq->data_len)
 779                                 rq->data_len = 0;
 780                         else
 781                                 rq->data_len -= cmd->act_len;
 782                 }
 783                 scsi_status = 0;
 784         } else {
 785                 if (blk_pc_request(rq)) {
 786                         /* UB_SENSE_SIZE is smaller than SCSI_SENSE_BUFFERSIZE */
 787                         memcpy(rq->sense, sc->top_sense, UB_SENSE_SIZE);
 788                         rq->sense_len = UB_SENSE_SIZE;
 789                         if (sc->top_sense[0] != 0)
 790                                 scsi_status = SAM_STAT_CHECK_CONDITION;
 791                         else
 792                                 scsi_status = DID_ERROR << 16;
 793                 } else {
 794                         if (cmd->error == -EIO) {
 795                                 if (ub_rw_cmd_retry(sc, lun, urq, cmd) == 0)
 796                                         return;
 797                         }
 798                         scsi_status = SAM_STAT_CHECK_CONDITION;
 799                 }
 800         }
 801
 802         urq->rq = NULL;
 803
 804         ub_put_cmd(lun, cmd);
 805         ub_end_rq(rq, scsi_status);
 806         blk_start_queue(lun->disk->queue);
 807 }
 808
 809 static void ub_end_rq(struct request *rq, unsigned int scsi_status)
 810 {
 811         int error;
 812
 813         if (scsi_status == 0) {
 814                 error = 0;
 815         } else {
 816                 error = -EIO;
 817                 rq->errors = scsi_status;
 818         }
 819         if (__blk_end_request(rq, error, blk_rq_bytes(rq)))
 820                 BUG();
 821 }
 822
 823 static int ub_rw_cmd_retry(struct ub_dev *sc, struct ub_lun *lun,
 824     struct ub_request *urq, struct ub_scsi_cmd *cmd)
 825 {
 826
 827         if (atomic_read(&sc->poison))
 828                 return -ENXIO;
 829
 830         ub_reset_enter(sc, urq->current_try);
 831
 832         if (urq->current_try >= 3)
 833                 return -EIO;
 834         urq->current_try++;
 835
 836         /* Remove this if anyone complains of flooding. */
 837         printk(KERN_DEBUG "%s: dir %c len/act %d/%d "
 838             "[sense %x %02x %02x] retry %d\n",
 839             sc->name, UB_DIR_CHAR(cmd->dir), cmd->len, cmd->act_len,
 840             cmd->key, cmd->asc, cmd->ascq, urq->current_try);
 841
 842         memset(cmd, 0, sizeof(struct ub_scsi_cmd));
 843         ub_cmd_build_block(sc, lun, cmd, urq);
 844
 845         cmd->state = UB_CMDST_INIT;
 846         cmd->lun = lun;
 847         cmd->done = ub_rw_cmd_done;
 848         cmd->back = urq;
 849
 850         cmd->tag = sc->tagcnt++;
 851
 852 #if 0 /* Wasteful */
 853         return ub_submit_scsi(sc, cmd);
 854 #else
 855         ub_cmdq_add(sc, cmd);
 856         return 0;
 857 #endif
 858 }
 859
 860 /*
 861  * Submit a regular SCSI operation (not an auto-sense).
 862  *
 863  * The Iron Law of Good Submit Routine is:
 864  * Zero return - callback is done, Nonzero return - callback is not done.
 865  * No exceptions.
 866  *
 867  * Host is assumed locked.
 868  */
 869 static int ub_submit_scsi(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 870 {
 871
 872         if (cmd->state != UB_CMDST_INIT ||
 873             (cmd->dir != UB_DIR_NONE && cmd->len == 0)) {
 874                 return -EINVAL;
 875         }
 876
 877         ub_cmdq_add(sc, cmd);
 878         /*
 879          * We can call ub_scsi_dispatch(sc) right away here, but it's a little
 880          * safer to jump to a tasklet, in case upper layers do something silly.
 881          */
 882         tasklet_schedule(&sc->tasklet);
 883         return 0;
 884 }
 885
 886 /*
 887  * Submit the first URB for the queued command.
 888  * This function does not deal with queueing in any way.
 889  */
 890 static int ub_scsi_cmd_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 891 {
 892         struct bulk_cb_wrap *bcb;
 893         int rc;
 894
 895         bcb = &sc->work_bcb;
 896
 897         /*
 898          * ``If the allocation length is eighteen or greater, and a device
 899          * server returns less than eithteen bytes of data, the application
 900          * client should assume that the bytes not transferred would have been
 901          * zeroes had the device server returned those bytes.''
 902          *
 903          * We zero sense for all commands so that when a packet request
 904          * fails it does not return a stale sense.
 905          */
 906         memset(&sc->top_sense, 0, UB_SENSE_SIZE);
 907
 908         /* set up the command wrapper */
 909         bcb->Signature = cpu_to_le32(US_BULK_CB_SIGN);
 910         bcb->Tag = cmd->tag;            /* Endianness is not important */
 911         bcb->DataTransferLength = cpu_to_le32(cmd->len);
 912         bcb->Flags = (cmd->dir == UB_DIR_READ) ? 0x80 : 0;
 913         bcb->Lun = (cmd->lun != NULL) ? cmd->lun->num : 0;
 914         bcb->Length = cmd->cdb_len;
 915
 916         /* copy the command payload */
 917         memcpy(bcb->CDB, cmd->cdb, UB_MAX_CDB_SIZE);
 918
 919         UB_INIT_COMPLETION(sc->work_done);
 920
 921         sc->last_pipe = sc->send_bulk_pipe;
 922         usb_fill_bulk_urb(&sc->work_urb, sc->dev, sc->send_bulk_pipe,
 923             bcb, US_BULK_CB_WRAP_LEN, ub_urb_complete, sc);
 924
 925         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
 926                 /* XXX Clear stalls */
 927                 ub_complete(&sc->work_done);
 928                 return rc;
 929         }
 930
 931         sc->work_timer.expires = jiffies + UB_URB_TIMEOUT;
 932         add_timer(&sc->work_timer);
 933
 934         cmd->state = UB_CMDST_CMD;
 935         return 0;
 936 }
 937
 938 /*
 939  * Timeout handler.
 940  */
 941 static void ub_urb_timeout(unsigned long arg)
 942 {
 943         struct ub_dev *sc = (struct ub_dev *) arg;
 944         unsigned long flags;
 945
 946         spin_lock_irqsave(sc->lock, flags);
 947         if (!ub_is_completed(&sc->work_done))
 948                 usb_unlink_urb(&sc->work_urb);
 949         spin_unlock_irqrestore(sc->lock, flags);
 950 }
 951
 952 /*
 953  * Completion routine for the work URB.
 954  *
 955  * This can be called directly from usb_submit_urb (while we have
 956  * the sc->lock taken) and from an interrupt (while we do NOT have
 957  * the sc->lock taken). Therefore, bounce this off to a tasklet.
 958  */
 959 static void ub_urb_complete(struct urb *urb)
 960 {
 961         struct ub_dev *sc = urb->context;
 962
 963         ub_complete(&sc->work_done);
 964         tasklet_schedule(&sc->tasklet);
 965 }
 966
 967 static void ub_scsi_action(unsigned long _dev)
 968 {
 969         struct ub_dev *sc = (struct ub_dev *) _dev;
 970         unsigned long flags;
 971
 972         spin_lock_irqsave(sc->lock, flags);
 973         ub_scsi_dispatch(sc);
 974         spin_unlock_irqrestore(sc->lock, flags);
 975 }
 976
 977 static void ub_scsi_dispatch(struct ub_dev *sc)
 978 {
 979         struct ub_scsi_cmd *cmd;
 980         int rc;
 981
 982         while (!sc->reset && (cmd = ub_cmdq_peek(sc)) != NULL) {
 983                 if (cmd->state == UB_CMDST_DONE) {
 984                         ub_cmdq_pop(sc);
 985                         (*cmd->done)(sc, cmd);
 986                 } else if (cmd->state == UB_CMDST_INIT) {
 987                         if ((rc = ub_scsi_cmd_start(sc, cmd)) == 0)
 988                                 break;
 989                         cmd->error = rc;
 990                         cmd->state = UB_CMDST_DONE;
 991                 } else {
 992                         if (!ub_is_completed(&sc->work_done))
 993                                 break;
 994                         del_timer(&sc->work_timer);
 995                         ub_scsi_urb_compl(sc, cmd);
 996                 }
 997         }
 998 }
 999
1000 static void ub_scsi_urb_compl(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1001 {
1002         struct urb *urb = &sc->work_urb;
1003         struct bulk_cs_wrap *bcs;
1004         int len;
1005         int rc;
1006
1007         if (atomic_read(&sc->poison)) {
1008                 ub_state_done(sc, cmd, -ENODEV);
1009                 return;
1010         }
1011
1012         if (cmd->state == UB_CMDST_CLEAR) {
1013                 if (urb->status == -EPIPE) {
1014                         /*
1015                          * STALL while clearning STALL.
1016                          * The control pipe clears itself - nothing to do.
1017                          */
1018                         printk(KERN_NOTICE "%s: stall on control pipe\n",
1019                             sc->name);
1020                         goto Bad_End;
1021                 }
1022
1023                 /*
1024                  * We ignore the result for the halt clear.
1025                  */
1026
1027                 /* reset the endpoint toggle */
1028                 usb_settoggle(sc->dev, usb_pipeendpoint(sc->last_pipe),
1029                         usb_pipeout(sc->last_pipe), 0);
1030
1031                 ub_state_sense(sc, cmd);
1032
1033         } else if (cmd->state == UB_CMDST_CLR2STS) {
1034                 if (urb->status == -EPIPE) {
1035                         printk(KERN_NOTICE "%s: stall on control pipe\n",
1036                             sc->name);
1037                         goto Bad_End;
1038                 }
1039
1040                 /*
1041                  * We ignore the result for the halt clear.
1042                  */
1043
1044                 /* reset the endpoint toggle */
1045                 usb_settoggle(sc->dev, usb_pipeendpoint(sc->last_pipe),
1046                         usb_pipeout(sc->last_pipe), 0);
1047
1048                 ub_state_stat(sc, cmd);
1049
1050         } else if (cmd->state == UB_CMDST_CLRRS) {
1051                 if (urb->status == -EPIPE) {
1052                         printk(KERN_NOTICE "%s: stall on control pipe\n",
1053                             sc->name);
1054                         goto Bad_End;
1055                 }
1056
1057                 /*
1058                  * We ignore the result for the halt clear.
1059                  */
1060
1061                 /* reset the endpoint toggle */
1062                 usb_settoggle(sc->dev, usb_pipeendpoint(sc->last_pipe),
1063                         usb_pipeout(sc->last_pipe), 0);
1064
1065                 ub_state_stat_counted(sc, cmd);
1066
1067         } else if (cmd->state == UB_CMDST_CMD) {
1068                 switch (urb->status) {
1069                 case 0:
1070                         break;
1071                 case -EOVERFLOW:
1072                         goto Bad_End;
1073                 case -EPIPE:
1074                         rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
1075                         if (rc != 0) {
1076                                 printk(KERN_NOTICE "%s: "
1077                                     "unable to submit clear (%d)\n",
1078                                     sc->name, rc);
1079                                 /*
1080                                  * This is typically ENOMEM or some other such shit.
1081                                  * Retrying is pointless. Just do Bad End on it...
1082                                  */
1083                                 ub_state_done(sc, cmd, rc);
1084                                 return;
1085                         }
1086                         cmd->state = UB_CMDST_CLEAR;
1087                         return;
1088                 case -ESHUTDOWN:        /* unplug */
1089                 case -EILSEQ:           /* unplug timeout on uhci */
1090                         ub_state_done(sc, cmd, -ENODEV);
1091                         return;
1092                 default:
1093                         goto Bad_End;
1094                 }
1095                 if (urb->actual_length != US_BULK_CB_WRAP_LEN) {
1096                         goto Bad_End;
1097                 }
1098
1099                 if (cmd->dir == UB_DIR_NONE || cmd->nsg < 1) {
1100                         ub_state_stat(sc, cmd);
1101                         return;
1102                 }
1103
1104                 // udelay(125);         // usb-storage has this
1105                 ub_data_start(sc, cmd);
1106
1107         } else if (cmd->state == UB_CMDST_DATA) {
1108                 if (urb->status == -EPIPE) {
1109                         rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
1110                         if (rc != 0) {
1111                                 printk(KERN_NOTICE "%s: "
1112                                     "unable to submit clear (%d)\n",
1113                                     sc->name, rc);
1114                                 ub_state_done(sc, cmd, rc);
1115                                 return;
1116                         }
1117                         cmd->state = UB_CMDST_CLR2STS;
1118                         return;
1119                 }
1120                 if (urb->status == -EOVERFLOW) {
1121                         /*
1122                          * A babble? Failure, but we must transfer CSW now.
1123                          */
1124                         cmd->error = -EOVERFLOW;        /* A cheap trick... */
1125                         ub_state_stat(sc, cmd);
1126                         return;
1127                 }
1128
1129                 if (cmd->dir == UB_DIR_WRITE) {
1130                         /*
1131                          * Do not continue writes in case of a failure.
1132                          * Doing so would cause sectors to be mixed up,
1133                          * which is worse than sectors lost.
1134                          *
1135                          * We must try to read the CSW, or many devices
1136                          * get confused.
1137                          */
1138                         len = urb->actual_length;
1139                         if (urb->status != 0 ||
1140                             len != cmd->sgv[cmd->current_sg].length) {
1141                                 cmd->act_len += len;
1142
1143                                 cmd->error = -EIO;
1144                                 ub_state_stat(sc, cmd);
1145                                 return;
1146                         }
1147
1148                 } else {
1149                         /*
1150                          * If an error occurs on read, we record it, and
1151                          * continue to fetch data in order to avoid bubble.
1152                          *
1153                          * As a small shortcut, we stop if we detect that
1154                          * a CSW mixed into data.
1155                          */
1156                         if (urb->status != 0)
1157                                 cmd->error = -EIO;
1158
1159                         len = urb->actual_length;
1160                         if (urb->status != 0 ||
1161                             len != cmd->sgv[cmd->current_sg].length) {
1162                                 if ((len & 0x1FF) == US_BULK_CS_WRAP_LEN)
1163                                         goto Bad_End;
1164                         }
1165                 }
1166
1167                 cmd->act_len += urb->actual_length;
1168
1169                 if (++cmd->current_sg < cmd->nsg) {
1170                         ub_data_start(sc, cmd);
1171                         return;
1172                 }
1173                 ub_state_stat(sc, cmd);
1174
1175         } else if (cmd->state == UB_CMDST_STAT) {
1176                 if (urb->status == -EPIPE) {
1177                         rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
1178                         if (rc != 0) {
1179                                 printk(KERN_NOTICE "%s: "
1180                                     "unable to submit clear (%d)\n",
1181                                     sc->name, rc);
1182                                 ub_state_done(sc, cmd, rc);
1183                                 return;
1184                         }
1185
1186                         /*
1187                          * Having a stall when getting CSW is an error, so
1188                          * make sure uppper levels are not oblivious to it.
1189                          */
1190                         cmd->error = -EIO;              /* A cheap trick... */
1191
1192                         cmd->state = UB_CMDST_CLRRS;
1193                         return;
1194                 }
1195
1196                 /* Catch everything, including -EOVERFLOW and other nasties. */
1197                 if (urb->status != 0)
1198                         goto Bad_End;
1199
1200                 if (urb->actual_length == 0) {
1201                         ub_state_stat_counted(sc, cmd);
1202                         return;
1203                 }
1204
1205                 /*
1206                  * Check the returned Bulk protocol status.
1207                  * The status block has to be validated first.
1208                  */
1209
1210                 bcs = &sc->work_bcs;
1211
1212                 if (sc->signature == cpu_to_le32(0)) {
1213                         /*
1214                          * This is the first reply, so do not perform the check.
1215                          * Instead, remember the signature the device uses
1216                          * for future checks. But do not allow a nul.
1217                          */
1218                         sc->signature = bcs->Signature;
1219                         if (sc->signature == cpu_to_le32(0)) {
1220                                 ub_state_stat_counted(sc, cmd);
1221                                 return;
1222                         }
1223                 } else {
1224                         if (bcs->Signature != sc->signature) {
1225                                 ub_state_stat_counted(sc, cmd);
1226                                 return;
1227                         }
1228                 }
1229
1230                 if (bcs->Tag != cmd->tag) {
1231                         /*
1232                          * This usually happens when we disagree with the
1233                          * device's microcode about something. For instance,
1234                          * a few of them throw this after timeouts. They buffer
1235                          * commands and reply at commands we timed out before.
1236                          * Without flushing these replies we loop forever.
1237                          */
1238                         ub_state_stat_counted(sc, cmd);
1239                         return;
1240                 }
1241
1242                 len = le32_to_cpu(bcs->Residue);
1243                 if (len != cmd->len - cmd->act_len) {
1244                         /*
1245                          * It is all right to transfer less, the caller has
1246                          * to check. But it's not all right if the device
1247                          * counts disagree with our counts.
1248                          */
1249                         goto Bad_End;
1250                 }
1251
1252                 switch (bcs->Status) {
1253                 case US_BULK_STAT_OK:
1254                         break;
1255                 case US_BULK_STAT_FAIL:
1256                         ub_state_sense(sc, cmd);
1257                         return;
1258                 case US_BULK_STAT_PHASE:
1259                         goto Bad_End;
1260                 default:
1261                         printk(KERN_INFO "%s: unknown CSW status 0x%x\n",
1262                             sc->name, bcs->Status);
1263                         ub_state_done(sc, cmd, -EINVAL);
1264                         return;
1265                 }
1266
1267                 /* Not zeroing error to preserve a babble indicator */
1268                 if (cmd->error != 0) {
1269                         ub_state_sense(sc, cmd);
1270                         return;
1271                 }
1272                 cmd->state = UB_CMDST_DONE;
1273                 ub_cmdq_pop(sc);
1274                 (*cmd->done)(sc, cmd);
1275
1276         } else if (cmd->state == UB_CMDST_SENSE) {
1277                 ub_state_done(sc, cmd, -EIO);
1278
1279         } else {
1280                 printk(KERN_WARNING "%s: "
1281                     "wrong command state %d\n",
1282                     sc->name, cmd->state);
1283                 ub_state_done(sc, cmd, -EINVAL);
1284                 return;
1285         }
1286         return;
1287
1288 Bad_End: /* Little Excel is dead */
1289         ub_state_done(sc, cmd, -EIO);
1290 }
1291
1292 /*
1293  * Factorization helper for the command state machine:
1294  * Initiate a data segment transfer.
1295  */
1296 static void ub_data_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1297 {
1298         struct scatterlist *sg = &cmd->sgv[cmd->current_sg];
1299         int pipe;
1300         int rc;
1301
1302         UB_INIT_COMPLETION(sc->work_done);
1303
1304         if (cmd->dir == UB_DIR_READ)
1305                 pipe = sc->recv_bulk_pipe;
1306         else
1307                 pipe = sc->send_bulk_pipe;
1308         sc->last_pipe = pipe;
1309         usb_fill_bulk_urb(&sc->work_urb, sc->dev, pipe, sg_virt(sg),
1310             sg->length, ub_urb_complete, sc);
1311
1312         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
1313                 /* XXX Clear stalls */
1314                 ub_complete(&sc->work_done);
1315                 ub_state_done(sc, cmd, rc);
1316                 return;
1317         }
1318
1319         sc->work_timer.expires = jiffies + UB_DATA_TIMEOUT;
1320         add_timer(&sc->work_timer);
1321
1322         cmd->state = UB_CMDST_DATA;
1323 }
1324
1325 /*
1326  * Factorization helper for the command state machine:
1327  * Finish the command.
1328  */
1329 static void ub_state_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd, int rc)
1330 {
1331
1332         cmd->error = rc;
1333         cmd->state = UB_CMDST_DONE;
1334         ub_cmdq_pop(sc);
1335         (*cmd->done)(sc, cmd);
1336 }
1337
1338 /*
1339  * Factorization helper for the command state machine:
1340  * Submit a CSW read.
1341  */
1342 static int __ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1343 {
1344         int rc;
1345
1346         UB_INIT_COMPLETION(sc->work_done);
1347
1348         sc->last_pipe = sc->recv_bulk_pipe;
1349         usb_fill_bulk_urb(&sc->work_urb, sc->dev, sc->recv_bulk_pipe,
1350             &sc->work_bcs, US_BULK_CS_WRAP_LEN, ub_urb_complete, sc);
1351
1352         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
1353                 /* XXX Clear stalls */
1354                 ub_complete(&sc->work_done);
1355                 ub_state_done(sc, cmd, rc);
1356                 return -1;
1357         }
1358
1359         sc->work_timer.expires = jiffies + UB_STAT_TIMEOUT;
1360         add_timer(&sc->work_timer);
1361         return 0;
1362 }
1363
1364 /*
1365  * Factorization helper for the command state machine:
1366  * Submit a CSW read and go to STAT state.
1367  */
1368 static void ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1369 {
1370
1371         if (__ub_state_stat(sc, cmd) != 0)
1372                 return;
1373
1374         cmd->stat_count = 0;
1375         cmd->state = UB_CMDST_STAT;
1376 }
1377
1378 /*
1379  * Factorization helper for the command state machine:
1380  * Submit a CSW read and go to STAT state with counter (along [C] path).
1381  */
1382 static void ub_state_stat_counted(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1383 {
1384
1385         if (++cmd->stat_count >= 4) {
1386                 ub_state_sense(sc, cmd);
1387                 return;
1388         }
1389
1390         if (__ub_state_stat(sc, cmd) != 0)
1391                 return;
1392
1393         cmd->state = UB_CMDST_STAT;
1394 }
1395
1396 /*
1397  * Factorization helper for the command state machine:
1398  * Submit a REQUEST SENSE and go to SENSE state.
1399  */
1400 static void ub_state_sense(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1401 {
1402         struct ub_scsi_cmd *scmd;
1403         struct scatterlist *sg;
1404         int rc;
1405
1406         if (cmd->cdb[0] == REQUEST_SENSE) {
1407                 rc = -EPIPE;
1408                 goto error;
1409         }
1410
1411         scmd = &sc->top_rqs_cmd;
1412         memset(scmd, 0, sizeof(struct ub_scsi_cmd));
1413         scmd->cdb[0] = REQUEST_SENSE;
1414         scmd->cdb[4] = UB_SENSE_SIZE;
1415         scmd->cdb_len = 6;
1416         scmd->dir = UB_DIR_READ;
1417         scmd->state = UB_CMDST_INIT;
1418         scmd->nsg = 1;
1419         sg = &scmd->sgv[0];
1420         sg_init_table(sg, UB_MAX_REQ_SG);
1421         sg_set_page(sg, virt_to_page(sc->top_sense), UB_SENSE_SIZE,
1422                         (unsigned long)sc->top_sense & (PAGE_SIZE-1));
1423         scmd->len = UB_SENSE_SIZE;
1424         scmd->lun = cmd->lun;
1425         scmd->done = ub_top_sense_done;
1426         scmd->back = cmd;
1427
1428         scmd->tag = sc->tagcnt++;
1429
1430         cmd->state = UB_CMDST_SENSE;
1431
1432         ub_cmdq_insert(sc, scmd);
1433         return;
1434
1435 error:
1436         ub_state_done(sc, cmd, rc);
1437 }
1438
1439 /*
1440  * A helper for the command's state machine:
1441  * Submit a stall clear.
1442  */
1443 static int ub_submit_clear_stall(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
1444     int stalled_pipe)
1445 {
1446         int endp;
1447         struct usb_ctrlrequest *cr;
1448         int rc;
1449
1450         endp = usb_pipeendpoint(stalled_pipe);
1451         if (usb_pipein (stalled_pipe))
1452                 endp |= USB_DIR_IN;
1453
1454         cr = &sc->work_cr;
1455         cr->bRequestType = USB_RECIP_ENDPOINT;
1456         cr->bRequest = USB_REQ_CLEAR_FEATURE;
1457         cr->wValue = cpu_to_le16(USB_ENDPOINT_HALT);
1458         cr->wIndex = cpu_to_le16(endp);
1459         cr->wLength = cpu_to_le16(0);
1460
1461         UB_INIT_COMPLETION(sc->work_done);
1462
1463         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->send_ctrl_pipe,
1464             (unsigned char*) cr, NULL, 0, ub_urb_complete, sc);
1465
1466         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
1467                 ub_complete(&sc->work_done);
1468                 return rc;
1469         }
1470
1471         sc->work_timer.expires = jiffies + UB_CTRL_TIMEOUT;
1472         add_timer(&sc->work_timer);
1473         return 0;
1474 }
1475
1476 /*
1477  */
1478 static void ub_top_sense_done(struct ub_dev *sc, struct ub_scsi_cmd *scmd)
1479 {
1480         unsigned char *sense = sc->top_sense;
1481         struct ub_scsi_cmd *cmd;
1482
1483         /*
1484          * Find the command which triggered the unit attention or a check,
1485          * save the sense into it, and advance its state machine.
1486          */
1487         if ((cmd = ub_cmdq_peek(sc)) == NULL) {
1488                 printk(KERN_WARNING "%s: sense done while idle\n", sc->name);
1489                 return;
1490         }
1491         if (cmd != scmd->back) {
1492                 printk(KERN_WARNING "%s: "
1493                     "sense done for wrong command 0x%x\n",
1494                     sc->name, cmd->tag);
1495                 return;
1496         }
1497         if (cmd->state != UB_CMDST_SENSE) {
1498                 printk(KERN_WARNING "%s: "
1499                     "sense done with bad cmd state %d\n",
1500                     sc->name, cmd->state);
1501                 return;
1502         }
1503
1504         /*
1505          * Ignoring scmd->act_len, because the buffer was pre-zeroed.
1506          */
1507         cmd->key = sense[2] & 0x0F;
1508         cmd->asc = sense[12];
1509         cmd->ascq = sense[13];
1510
1511         ub_scsi_urb_compl(sc, cmd);
1512 }
1513
1514 /*
1515  * Reset management
1516  * XXX Move usb_reset_device to khubd. Hogging kevent is not a good thing.
1517  * XXX Make usb_sync_reset asynchronous.
1518  */
1519
1520 static void ub_reset_enter(struct ub_dev *sc, int try)
1521 {
1522
1523         if (sc->reset) {
1524                 /* This happens often on multi-LUN devices. */
1525                 return;
1526         }
1527         sc->reset = try + 1;
1528
1529 #if 0 /* Not needed because the disconnect waits for us. */
1530         unsigned long flags;
1531         spin_lock_irqsave(&ub_lock, flags);
1532         sc->openc++;
1533         spin_unlock_irqrestore(&ub_lock, flags);
1534 #endif
1535
1536 #if 0 /* We let them stop themselves. */
1537         struct ub_lun *lun;
1538         list_for_each_entry(lun, &sc->luns, link) {
1539                 blk_stop_queue(lun->disk->queue);
1540         }
1541 #endif
1542
1543         schedule_work(&sc->reset_work);
1544 }
1545
1546 static void ub_reset_task(struct work_struct *work)
1547 {
1548         struct ub_dev *sc = container_of(work, struct ub_dev, reset_work);
1549         unsigned long flags;
1550         struct ub_lun *lun;
1551         int lkr, rc;
1552
1553         if (!sc->reset) {
1554                 printk(KERN_WARNING "%s: Running reset unrequested\n",
1555                     sc->name);
1556                 return;
1557         }
1558
1559         if (atomic_read(&sc->poison)) {
1560                 ;
1561         } else if ((sc->reset & 1) == 0) {
1562                 ub_sync_reset(sc);
1563                 msleep(700);    /* usb-storage sleeps 6s (!) */
1564                 ub_probe_clear_stall(sc, sc->recv_bulk_pipe);
1565                 ub_probe_clear_stall(sc, sc->send_bulk_pipe);
1566         } else if (sc->dev->actconfig->desc.bNumInterfaces != 1) {
1567                 ;
1568         } else {
1569                 if ((lkr = usb_lock_device_for_reset(sc->dev, sc->intf)) < 0) {
1570                         printk(KERN_NOTICE
1571                             "%s: usb_lock_device_for_reset failed (%d)\n",
1572                             sc->name, lkr);
1573                 } else {
1574                         rc = usb_reset_device(sc->dev);
1575                         if (rc < 0) {
1576                                 printk(KERN_NOTICE "%s: "
1577                                     "usb_lock_device_for_reset failed (%d)\n",
1578                                     sc->name, rc);
1579                         }
1580
1581                         if (lkr)
1582                                 usb_unlock_device(sc->dev);
1583                 }
1584         }
1585
1586         /*
1587          * In theory, no commands can be running while reset is active,
1588          * so nobody can ask for another reset, and so we do not need any
1589          * queues of resets or anything. We do need a spinlock though,
1590          * to interact with block layer.
1591          */
1592         spin_lock_irqsave(sc->lock, flags);
1593         sc->reset = 0;
1594         tasklet_schedule(&sc->tasklet);
1595         list_for_each_entry(lun, &sc->luns, link) {
1596                 blk_start_queue(lun->disk->queue);
1597         }
1598         wake_up(&sc->reset_wait);
1599         spin_unlock_irqrestore(sc->lock, flags);
1600 }
1601
1602 /*
1603  * This is called from a process context.
1604  */
1605 static void ub_revalidate(struct ub_dev *sc, struct ub_lun *lun)
1606 {
1607
1608         lun->readonly = 0;      /* XXX Query this from the device */
1609
1610         lun->capacity.nsec = 0;
1611         lun->capacity.bsize = 512;
1612         lun->capacity.bshift = 0;
1613
1614         if (ub_sync_tur(sc, lun) != 0)
1615                 return;                 /* Not ready */
1616         lun->changed = 0;
1617
1618         if (ub_sync_read_cap(sc, lun, &lun->capacity) != 0) {
1619                 /*
1620                  * The retry here means something is wrong, either with the
1621                  * device, with the transport, or with our code.
1622                  * We keep this because sd.c has retries for capacity.
1623                  */
1624                 if (ub_sync_read_cap(sc, lun, &lun->capacity) != 0) {
1625                         lun->capacity.nsec = 0;
1626                         lun->capacity.bsize = 512;
1627                         lun->capacity.bshift = 0;
1628                 }
1629         }
1630 }
1631
1632 /*
1633  * The open funcion.
1634  * This is mostly needed to keep refcounting, but also to support
1635  * media checks on removable media drives.
1636  */
1637 static int ub_bd_open(struct inode *inode, struct file *filp)
1638 {
1639         struct gendisk *disk = inode->i_bdev->bd_disk;
1640         struct ub_lun *lun = disk->private_data;
1641         struct ub_dev *sc = lun->udev;
1642         unsigned long flags;
1643         int rc;
1644
1645         spin_lock_irqsave(&ub_lock, flags);
1646         if (atomic_read(&sc->poison)) {
1647                 spin_unlock_irqrestore(&ub_lock, flags);
1648                 return -ENXIO;
1649         }
1650         sc->openc++;
1651         spin_unlock_irqrestore(&ub_lock, flags);
1652
1653         if (lun->removable || lun->readonly)
1654                 check_disk_change(inode->i_bdev);
1655
1656         /*
1657          * The sd.c considers ->media_present and ->changed not equivalent,
1658          * under some pretty murky conditions (a failure of READ CAPACITY).
1659          * We may need it one day.
1660          */
1661         if (lun->removable && lun->changed && !(filp->f_flags & O_NDELAY)) {
1662                 rc = -ENOMEDIUM;
1663                 goto err_open;
1664         }
1665
1666         if (lun->readonly && (filp->f_mode & FMODE_WRITE)) {
1667                 rc = -EROFS;
1668                 goto err_open;
1669         }
1670
1671         return 0;
1672
1673 err_open:
1674         ub_put(sc);
1675         return rc;
1676 }
1677
1678 /*
1679  */
1680 static int ub_bd_release(struct inode *inode, struct file *filp)
1681 {
1682         struct gendisk *disk = inode->i_bdev->bd_disk;
1683         struct ub_lun *lun = disk->private_data;
1684         struct ub_dev *sc = lun->udev;
1685
1686         ub_put(sc);
1687         return 0;
1688 }
1689
1690 /*
1691  * The ioctl interface.
1692  */
1693 static int ub_bd_ioctl(struct inode *inode, struct file *filp,
1694     unsigned int cmd, unsigned long arg)
1695 {
1696         struct gendisk *disk = inode->i_bdev->bd_disk;
1697         void __user *usermem = (void __user *) arg;
1698
1699         return scsi_cmd_ioctl(filp, disk->queue, disk, cmd, usermem);
1700 }
1701
1702 /*
1703  * This is called once a new disk was seen by the block layer or by ub_probe().
1704  * The main onjective here is to discover the features of the media such as
1705  * the capacity, read-only status, etc. USB storage generally does not
1706  * need to be spun up, but if we needed it, this would be the place.
1707  *
1708  * This call can sleep.
1709  *
1710  * The return code is not used.
1711  */
1712 static int ub_bd_revalidate(struct gendisk *disk)
1713 {
1714         struct ub_lun *lun = disk->private_data;
1715
1716         ub_revalidate(lun->udev, lun);
1717
1718         /* XXX Support sector size switching like in sr.c */
1719         blk_queue_hardsect_size(disk->queue, lun->capacity.bsize);
1720         set_capacity(disk, lun->capacity.nsec);
1721         // set_disk_ro(sdkp->disk, lun->readonly);
1722
1723         return 0;
1724 }
1725
1726 /*
1727  * The check is called by the block layer to verify if the media
1728  * is still available. It is supposed to be harmless, lightweight and
1729  * non-intrusive in case the media was not changed.
1730  *
1731  * This call can sleep.
1732  *
1733  * The return code is bool!
1734  */
1735 static int ub_bd_media_changed(struct gendisk *disk)
1736 {
1737         struct ub_lun *lun = disk->private_data;
1738
1739         if (!lun->removable)
1740                 return 0;
1741
1742         /*
1743          * We clean checks always after every command, so this is not
1744          * as dangerous as it looks. If the TEST_UNIT_READY fails here,
1745          * the device is actually not ready with operator or software
1746          * intervention required. One dangerous item might be a drive which
1747          * spins itself down, and come the time to write dirty pages, this
1748          * will fail, then block layer discards the data. Since we never
1749          * spin drives up, such devices simply cannot be used with ub anyway.
1750          */
1751         if (ub_sync_tur(lun->udev, lun) != 0) {
1752                 lun->changed = 1;
1753                 return 1;
1754         }
1755
1756         return lun->changed;
1757 }
1758
1759 static struct block_device_operations ub_bd_fops = {
1760         .owner          = THIS_MODULE,
1761         .open           = ub_bd_open,
1762         .release        = ub_bd_release,
1763         .ioctl          = ub_bd_ioctl,
1764         .media_changed  = ub_bd_media_changed,
1765         .revalidate_disk = ub_bd_revalidate,
1766 };
1767
1768 /*
1769  * Common ->done routine for commands executed synchronously.
1770  */
1771 static void ub_probe_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1772 {
1773         struct completion *cop = cmd->back;
1774         complete(cop);
1775 }
1776
1777 /*
1778  * Test if the device has a check condition on it, synchronously.
1779  */
1780 static int ub_sync_tur(struct ub_dev *sc, struct ub_lun *lun)
1781 {
1782         struct ub_scsi_cmd *cmd;
1783         enum { ALLOC_SIZE = sizeof(struct ub_scsi_cmd) };
1784         unsigned long flags;
1785         struct completion compl;
1786         int rc;
1787
1788         init_completion(&compl);
1789
1790         rc = -ENOMEM;
1791         if ((cmd = kzalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
1792                 goto err_alloc;
1793
1794         cmd->cdb[0] = TEST_UNIT_READY;
1795         cmd->cdb_len = 6;
1796         cmd->dir = UB_DIR_NONE;
1797         cmd->state = UB_CMDST_INIT;
1798         cmd->lun = lun;                 /* This may be NULL, but that's ok */
1799         cmd->done = ub_probe_done;
1800         cmd->back = &compl;
1801
1802         spin_lock_irqsave(sc->lock, flags);
1803         cmd->tag = sc->tagcnt++;
1804
1805         rc = ub_submit_scsi(sc, cmd);
1806         spin_unlock_irqrestore(sc->lock, flags);
1807
1808         if (rc != 0)
1809                 goto err_submit;
1810
1811         wait_for_completion(&compl);
1812
1813         rc = cmd->error;
1814
1815         if (rc == -EIO && cmd->key != 0)        /* Retries for benh's key */
1816                 rc = cmd->key;
1817
1818 err_submit:
1819         kfree(cmd);
1820 err_alloc:
1821         return rc;
1822 }
1823
1824 /*
1825  * Read the SCSI capacity synchronously (for probing).
1826  */
1827 static int ub_sync_read_cap(struct ub_dev *sc, struct ub_lun *lun,
1828     struct ub_capacity *ret)
1829 {
1830         struct ub_scsi_cmd *cmd;
1831         struct scatterlist *sg;
1832         char *p;
1833         enum { ALLOC_SIZE = sizeof(struct ub_scsi_cmd) + 8 };
1834         unsigned long flags;
1835         unsigned int bsize, shift;
1836         unsigned long nsec;
1837         struct completion compl;
1838         int rc;
1839
1840         init_completion(&compl);
1841
1842         rc = -ENOMEM;
1843         if ((cmd = kzalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
1844                 goto err_alloc;
1845         p = (char *)cmd + sizeof(struct ub_scsi_cmd);
1846
1847         cmd->cdb[0] = 0x25;
1848         cmd->cdb_len = 10;
1849         cmd->dir = UB_DIR_READ;
1850         cmd->state = UB_CMDST_INIT;
1851         cmd->nsg = 1;
1852         sg = &cmd->sgv[0];
1853         sg_init_table(sg, UB_MAX_REQ_SG);
1854         sg_set_page(sg, virt_to_page(p), 8, (unsigned long)p & (PAGE_SIZE-1));
1855         cmd->len = 8;
1856         cmd->lun = lun;
1857         cmd->done = ub_probe_done;
1858         cmd->back = &compl;
1859
1860         spin_lock_irqsave(sc->lock, flags);
1861         cmd->tag = sc->tagcnt++;
1862
1863         rc = ub_submit_scsi(sc, cmd);
1864         spin_unlock_irqrestore(sc->lock, flags);
1865
1866         if (rc != 0)
1867                 goto err_submit;
1868
1869         wait_for_completion(&compl);
1870
1871         if (cmd->error != 0) {
1872                 rc = -EIO;
1873                 goto err_read;
1874         }
1875         if (cmd->act_len != 8) {
1876                 rc = -EIO;
1877                 goto err_read;
1878         }
1879
1880         /* sd.c special-cases sector size of 0 to mean 512. Needed? Safe? */
1881         nsec = be32_to_cpu(*(__be32 *)p) + 1;
1882         bsize = be32_to_cpu(*(__be32 *)(p + 4));
1883         switch (bsize) {
1884         case 512:       shift = 0;      break;
1885         case 1024:      shift = 1;      break;
1886         case 2048:      shift = 2;      break;
1887         case 4096:      shift = 3;      break;
1888         default:
1889                 rc = -EDOM;
1890                 goto err_inv_bsize;
1891         }
1892
1893         ret->bsize = bsize;
1894         ret->bshift = shift;
1895         ret->nsec = nsec << shift;
1896         rc = 0;
1897
1898 err_inv_bsize:
1899 err_read:
1900 err_submit:
1901         kfree(cmd);
1902 err_alloc:
1903         return rc;
1904 }
1905
1906 /*
1907  */
1908 static void ub_probe_urb_complete(struct urb *urb)
1909 {
1910         struct completion *cop = urb->context;
1911         complete(cop);
1912 }
1913
1914 static void ub_probe_timeout(unsigned long arg)
1915 {
1916         struct completion *cop = (struct completion *) arg;
1917         complete(cop);
1918 }
1919
1920 /*
1921  * Reset with a Bulk reset.
1922  */
1923 static int ub_sync_reset(struct ub_dev *sc)
1924 {
1925         int ifnum = sc->intf->cur_altsetting->desc.bInterfaceNumber;
1926         struct usb_ctrlrequest *cr;
1927         struct completion compl;
1928         struct timer_list timer;
1929         int rc;
1930
1931         init_completion(&compl);
1932
1933         cr = &sc->work_cr;
1934         cr->bRequestType = USB_TYPE_CLASS | USB_RECIP_INTERFACE;
1935         cr->bRequest = US_BULK_RESET_REQUEST;
1936         cr->wValue = cpu_to_le16(0);
1937         cr->wIndex = cpu_to_le16(ifnum);
1938         cr->wLength = cpu_to_le16(0);
1939
1940         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->send_ctrl_pipe,
1941             (unsigned char*) cr, NULL, 0, ub_probe_urb_complete, &compl);
1942
1943         if ((rc = usb_submit_urb(&sc->work_urb, GFP_KERNEL)) != 0) {
1944                 printk(KERN_WARNING
1945                      "%s: Unable to submit a bulk reset (%d)\n", sc->name, rc);
1946                 return rc;
1947         }
1948
1949         init_timer(&timer);
1950         timer.function = ub_probe_timeout;
1951         timer.data = (unsigned long) &compl;
1952         timer.expires = jiffies + UB_CTRL_TIMEOUT;
1953         add_timer(&timer);
1954
1955         wait_for_completion(&compl);
1956
1957         del_timer_sync(&timer);
1958         usb_kill_urb(&sc->work_urb);
1959
1960         return sc->work_urb.status;
1961 }
1962
1963 /*
1964  * Get number of LUNs by the way of Bulk GetMaxLUN command.
1965  */
1966 static int ub_sync_getmaxlun(struct ub_dev *sc)
1967 {
1968         int ifnum = sc->intf->cur_altsetting->desc.bInterfaceNumber;
1969         unsigned char *p;
1970         enum { ALLOC_SIZE = 1 };
1971         struct usb_ctrlrequest *cr;
1972         struct completion compl;
1973         struct timer_list timer;
1974         int nluns;
1975         int rc;
1976
1977         init_completion(&compl);
1978
1979         rc = -ENOMEM;
1980         if ((p = kmalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
1981                 goto err_alloc;
1982         *p = 55;
1983
1984         cr = &sc->work_cr;
1985         cr->bRequestType = USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE;
1986         cr->bRequest = US_BULK_GET_MAX_LUN;
1987         cr->wValue = cpu_to_le16(0);
1988         cr->wIndex = cpu_to_le16(ifnum);
1989         cr->wLength = cpu_to_le16(1);
1990
1991         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->recv_ctrl_pipe,
1992             (unsigned char*) cr, p, 1, ub_probe_urb_complete, &compl);
1993
1994         if ((rc = usb_submit_urb(&sc->work_urb, GFP_KERNEL)) != 0)
1995                 goto err_submit;
1996
1997         init_timer(&timer);
1998         timer.function = ub_probe_timeout;
1999         timer.data = (unsigned long) &compl;
2000         timer.expires = jiffies + UB_CTRL_TIMEOUT;
2001         add_timer(&timer);
2002
2003         wait_for_completion(&compl);
2004
2005         del_timer_sync(&timer);
2006         usb_kill_urb(&sc->work_urb);
2007
2008         if ((rc = sc->work_urb.status) < 0)
2009                 goto err_io;
2010
2011         if (sc->work_urb.actual_length != 1) {
2012                 nluns = 0;
2013         } else {
2014                 if ((nluns = *p) == 55) {
2015                         nluns = 0;
2016                 } else {
2017                         /* GetMaxLUN returns the maximum LUN number */
2018                         nluns += 1;
2019                         if (nluns > UB_MAX_LUNS)
2020                                 nluns = UB_MAX_LUNS;
2021                 }
2022         }
2023
2024         kfree(p);
2025         return nluns;
2026
2027 err_io:
2028 err_submit:
2029         kfree(p);
2030 err_alloc:
2031         return rc;
2032 }
2033
2034 /*
2035  * Clear initial stalls.
2036  */
2037 static int ub_probe_clear_stall(struct ub_dev *sc, int stalled_pipe)
2038 {
2039         int endp;
2040         struct usb_ctrlrequest *cr;
2041         struct completion compl;
2042         struct timer_list timer;
2043         int rc;
2044
2045         init_completion(&compl);
2046
2047         endp = usb_pipeendpoint(stalled_pipe);
2048         if (usb_pipein (stalled_pipe))
2049                 endp |= USB_DIR_IN;
2050
2051         cr = &sc->work_cr;
2052         cr->bRequestType = USB_RECIP_ENDPOINT;
2053         cr->bRequest = USB_REQ_CLEAR_FEATURE;
2054         cr->wValue = cpu_to_le16(USB_ENDPOINT_HALT);
2055         cr->wIndex = cpu_to_le16(endp);
2056         cr->wLength = cpu_to_le16(0);
2057
2058         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->send_ctrl_pipe,
2059             (unsigned char*) cr, NULL, 0, ub_probe_urb_complete, &compl);
2060
2061         if ((rc = usb_submit_urb(&sc->work_urb, GFP_KERNEL)) != 0) {
2062                 printk(KERN_WARNING
2063                      "%s: Unable to submit a probe clear (%d)\n", sc->name, rc);
2064                 return rc;
2065         }
2066
2067         init_timer(&timer);
2068         timer.function = ub_probe_timeout;
2069         timer.data = (unsigned long) &compl;
2070         timer.expires = jiffies + UB_CTRL_TIMEOUT;
2071         add_timer(&timer);
2072
2073         wait_for_completion(&compl);
2074
2075         del_timer_sync(&timer);
2076         usb_kill_urb(&sc->work_urb);
2077
2078         /* reset the endpoint toggle */
2079         usb_settoggle(sc->dev, endp, usb_pipeout(sc->last_pipe), 0);
2080
2081         return 0;
2082 }
2083
2084 /*
2085  * Get the pipe settings.
2086  */
2087 static int ub_get_pipes(struct ub_dev *sc, struct usb_device *dev,
2088     struct usb_interface *intf)
2089 {
2090         struct usb_host_interface *altsetting = intf->cur_altsetting;
2091         struct usb_endpoint_descriptor *ep_in = NULL;
2092         struct usb_endpoint_descriptor *ep_out = NULL;
2093         struct usb_endpoint_descriptor *ep;
2094         int i;
2095
2096         /*
2097          * Find the endpoints we need.
2098          * We are expecting a minimum of 2 endpoints - in and out (bulk).
2099          * We will ignore any others.
2100          */
2101         for (i = 0; i < altsetting->desc.bNumEndpoints; i++) {
2102                 ep = &altsetting->endpoint[i].desc;
2103
2104                 /* Is it a BULK endpoint? */
2105                 if ((ep->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK)
2106                                 == USB_ENDPOINT_XFER_BULK) {
2107                         /* BULK in or out? */
2108                         if (ep->bEndpointAddress & USB_DIR_IN) {
2109                                 if (ep_in == NULL)
2110                                         ep_in = ep;
2111                         } else {
2112                                 if (ep_out == NULL)
2113                                         ep_out = ep;
2114                         }
2115                 }
2116         }
2117
2118         if (ep_in == NULL || ep_out == NULL) {
2119                 printk(KERN_NOTICE "%s: failed endpoint check\n",
2120                     sc->name);
2121                 return -ENODEV;
2122         }
2123
2124         /* Calculate and store the pipe values */
2125         sc->send_ctrl_pipe = usb_sndctrlpipe(dev, 0);
2126         sc->recv_ctrl_pipe = usb_rcvctrlpipe(dev, 0);
2127         sc->send_bulk_pipe = usb_sndbulkpipe(dev,
2128                 ep_out->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2129         sc->recv_bulk_pipe = usb_rcvbulkpipe(dev,
2130                 ep_in->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2131
2132         return 0;
2133 }
2134
2135 /*
2136  * Probing is done in the process context, which allows us to cheat
2137  * and not to build a state machine for the discovery.
2138  */
2139 static int ub_probe(struct usb_interface *intf,
2140     const struct usb_device_id *dev_id)
2141 {
2142         struct ub_dev *sc;
2143         int nluns;
2144         int rc;
2145         int i;
2146
2147         if (usb_usual_check_type(dev_id, USB_US_TYPE_UB))
2148                 return -ENXIO;
2149
2150         rc = -ENOMEM;
2151         if ((sc = kzalloc(sizeof(struct ub_dev), GFP_KERNEL)) == NULL)
2152                 goto err_core;
2153         sc->lock = ub_next_lock();
2154         INIT_LIST_HEAD(&sc->luns);
2155         usb_init_urb(&sc->work_urb);
2156         tasklet_init(&sc->tasklet, ub_scsi_action, (unsigned long)sc);
2157         atomic_set(&sc->poison, 0);
2158         INIT_WORK(&sc->reset_work, ub_reset_task);
2159         init_waitqueue_head(&sc->reset_wait);
2160
2161         init_timer(&sc->work_timer);
2162         sc->work_timer.data = (unsigned long) sc;
2163         sc->work_timer.function = ub_urb_timeout;
2164
2165         ub_init_completion(&sc->work_done);
2166         sc->work_done.done = 1;         /* A little yuk, but oh well... */
2167
2168         sc->dev = interface_to_usbdev(intf);
2169         sc->intf = intf;
2170         // sc->ifnum = intf->cur_altsetting->desc.bInterfaceNumber;
2171         usb_set_intfdata(intf, sc);
2172         usb_get_dev(sc->dev);
2173         /*
2174          * Since we give the interface struct to the block level through
2175          * disk->driverfs_dev, we have to pin it. Otherwise, block_uevent
2176          * oopses on close after a disconnect (kernels 2.6.16 and up).
2177          */
2178         usb_get_intf(sc->intf);
2179
2180         snprintf(sc->name, 12, DRV_NAME "(%d.%d)",
2181             sc->dev->bus->busnum, sc->dev->devnum);
2182
2183         /* XXX Verify that we can handle the device (from descriptors) */
2184
2185         if (ub_get_pipes(sc, sc->dev, intf) != 0)
2186                 goto err_dev_desc;
2187
2188         /*
2189          * At this point, all USB initialization is done, do upper layer.
2190          * We really hate halfway initialized structures, so from the
2191          * invariants perspective, this ub_dev is fully constructed at
2192          * this point.
2193          */
2194
2195         /*
2196          * This is needed to clear toggles. It is a problem only if we do
2197          * `rmmod ub && modprobe ub` without disconnects, but we like that.
2198          */
2199 #if 0 /* iPod Mini fails if we do this (big white iPod works) */
2200         ub_probe_clear_stall(sc, sc->recv_bulk_pipe);
2201         ub_probe_clear_stall(sc, sc->send_bulk_pipe);
2202 #endif
2203
2204         /*
2205          * The way this is used by the startup code is a little specific.
2206          * A SCSI check causes a USB stall. Our common case code sees it
2207          * and clears the check, after which the device is ready for use.
2208          * But if a check was not present, any command other than
2209          * TEST_UNIT_READY ends with a lockup (including REQUEST_SENSE).
2210          *
2211          * If we neglect to clear the SCSI check, the first real command fails
2212          * (which is the capacity readout). We clear that and retry, but why
2213          * causing spurious retries for no reason.
2214          *
2215          * Revalidation may start with its own TEST_UNIT_READY, but that one
2216          * has to succeed, so we clear checks with an additional one here.
2217          * In any case it's not our business how revaliadation is implemented.
2218          */
2219         for (i = 0; i < 3; i++) {  /* Retries for the schwag key from KS'04 */
2220                 if ((rc = ub_sync_tur(sc, NULL)) <= 0) break;
2221                 if (rc != 0x6) break;
2222                 msleep(10);
2223         }
2224
2225         nluns = 1;
2226         for (i = 0; i < 3; i++) {
2227                 if ((rc = ub_sync_getmaxlun(sc)) < 0)
2228                         break;
2229                 if (rc != 0) {
2230                         nluns = rc;
2231                         break;
2232                 }
2233                 msleep(100);
2234         }
2235
2236         for (i = 0; i < nluns; i++) {
2237                 ub_probe_lun(sc, i);
2238         }
2239         return 0;
2240
2241 err_dev_desc:
2242         usb_set_intfdata(intf, NULL);
2243         usb_put_intf(sc->intf);
2244         usb_put_dev(sc->dev);
2245         kfree(sc);
2246 err_core:
2247         return rc;
2248 }
2249
2250 static int ub_probe_lun(struct ub_dev *sc, int lnum)
2251 {
2252         struct ub_lun *lun;
2253         struct request_queue *q;
2254         struct gendisk *disk;
2255         int rc;
2256
2257         rc = -ENOMEM;
2258         if ((lun = kzalloc(sizeof(struct ub_lun), GFP_KERNEL)) == NULL)
2259                 goto err_alloc;
2260         lun->num = lnum;
2261
2262         rc = -ENOSR;
2263         if ((lun->id = ub_id_get()) == -1)
2264                 goto err_id;
2265
2266         lun->udev = sc;
2267
2268         snprintf(lun->name, 16, DRV_NAME "%c(%d.%d.%d)",
2269             lun->id + 'a', sc->dev->bus->busnum, sc->dev->devnum, lun->num);
2270
2271         lun->removable = 1;             /* XXX Query this from the device */
2272         lun->changed = 1;               /* ub_revalidate clears only */
2273         ub_revalidate(sc, lun);
2274
2275         rc = -ENOMEM;
2276         if ((disk = alloc_disk(UB_PARTS_PER_LUN)) == NULL)
2277                 goto err_diskalloc;
2278
2279         sprintf(disk->disk_name, DRV_NAME "%c", lun->id + 'a');
2280         disk->major = UB_MAJOR;
2281         disk->first_minor = lun->id * UB_PARTS_PER_LUN;
2282         disk->fops = &ub_bd_fops;
2283         disk->private_data = lun;
2284         disk->driverfs_dev = &sc->intf->dev;
2285
2286         rc = -ENOMEM;
2287         if ((q = blk_init_queue(ub_request_fn, sc->lock)) == NULL)
2288                 goto err_blkqinit;
2289
2290         disk->queue = q;
2291
2292         blk_queue_bounce_limit(q, BLK_BOUNCE_HIGH);
2293         blk_queue_max_hw_segments(q, UB_MAX_REQ_SG);
2294         blk_queue_max_phys_segments(q, UB_MAX_REQ_SG);
2295         blk_queue_segment_boundary(q, 0xffffffff);      /* Dubious. */
2296         blk_queue_max_sectors(q, UB_MAX_SECTORS);
2297         blk_queue_hardsect_size(q, lun->capacity.bsize);
2298
2299         lun->disk = disk;
2300         q->queuedata = lun;
2301         list_add(&lun->link, &sc->luns);
2302
2303         set_capacity(disk, lun->capacity.nsec);
2304         if (lun->removable)
2305                 disk->flags |= GENHD_FL_REMOVABLE;
2306
2307         add_disk(disk);
2308
2309         return 0;
2310
2311 err_blkqinit:
2312         put_disk(disk);
2313 err_diskalloc:
2314         ub_id_put(lun->id);
2315 err_id:
2316         kfree(lun);
2317 err_alloc:
2318         return rc;
2319 }
2320
2321 static void ub_disconnect(struct usb_interface *intf)
2322 {
2323         struct ub_dev *sc = usb_get_intfdata(intf);
2324         struct ub_lun *lun;
2325         unsigned long flags;
2326
2327         /*
2328          * Prevent ub_bd_release from pulling the rug from under us.
2329          * XXX This is starting to look like a kref.
2330          * XXX Why not to take this ref at probe time?
2331          */
2332         spin_lock_irqsave(&ub_lock, flags);
2333         sc->openc++;
2334         spin_unlock_irqrestore(&ub_lock, flags);
2335
2336         /*
2337          * Fence stall clearnings, operations triggered by unlinkings and so on.
2338          * We do not attempt to unlink any URBs, because we do not trust the
2339          * unlink paths in HC drivers. Also, we get -84 upon disconnect anyway.
2340          */
2341         atomic_set(&sc->poison, 1);
2342
2343         /*
2344          * Wait for reset to end, if any.
2345          */
2346         wait_event(sc->reset_wait, !sc->reset);
2347
2348         /*
2349          * Blow away queued commands.
2350          *
2351          * Actually, this never works, because before we get here
2352          * the HCD terminates outstanding URB(s). It causes our
2353          * SCSI command queue to advance, commands fail to submit,
2354          * and the whole queue drains. So, we just use this code to
2355          * print warnings.
2356          */
2357         spin_lock_irqsave(sc->lock, flags);
2358         {
2359                 struct ub_scsi_cmd *cmd;
2360                 int cnt = 0;
2361                 while ((cmd = ub_cmdq_peek(sc)) != NULL) {
2362                         cmd->error = -ENOTCONN;
2363                         cmd->state = UB_CMDST_DONE;
2364                         ub_cmdq_pop(sc);
2365                         (*cmd->done)(sc, cmd);
2366                         cnt++;
2367                 }
2368                 if (cnt != 0) {
2369                         printk(KERN_WARNING "%s: "
2370                             "%d was queued after shutdown\n", sc->name, cnt);
2371                 }
2372         }
2373         spin_unlock_irqrestore(sc->lock, flags);
2374
2375         /*
2376          * Unregister the upper layer.
2377          */
2378         list_for_each_entry(lun, &sc->luns, link) {
2379                 del_gendisk(lun->disk);
2380                 /*
2381                  * I wish I could do:
2382                  *    set_bit(QUEUE_FLAG_DEAD, &q->queue_flags);
2383                  * As it is, we rely on our internal poisoning and let
2384                  * the upper levels to spin furiously failing all the I/O.
2385                  */
2386         }
2387
2388         /*
2389          * Testing for -EINPROGRESS is always a bug, so we are bending
2390          * the rules a little.
2391          */
2392         spin_lock_irqsave(sc->lock, flags);
2393         if (sc->work_urb.status == -EINPROGRESS) {      /* janitors: ignore */
2394                 printk(KERN_WARNING "%s: "
2395                     "URB is active after disconnect\n", sc->name);
2396         }
2397         spin_unlock_irqrestore(sc->lock, flags);
2398
2399         /*
2400          * There is virtually no chance that other CPU runs times so long
2401          * after ub_urb_complete should have called del_timer, but only if HCD
2402          * didn't forget to deliver a callback on unlink.
2403          */
2404         del_timer_sync(&sc->work_timer);
2405
2406         /*
2407          * At this point there must be no commands coming from anyone
2408          * and no URBs left in transit.
2409          */
2410
2411         ub_put(sc);
2412 }
2413
2414 static struct usb_driver ub_driver = {
2415         .name =         "ub",
2416         .probe =        ub_probe,
2417         .disconnect =   ub_disconnect,
2418         .id_table =     ub_usb_ids,
2419 };
2420
2421 static int __init ub_init(void)
2422 {
2423         int rc;
2424         int i;
2425
2426         for (i = 0; i < UB_QLOCK_NUM; i++)
2427                 spin_lock_init(&ub_qlockv[i]);
2428
2429         if ((rc = register_blkdev(UB_MAJOR, DRV_NAME)) != 0)
2430                 goto err_regblkdev;
2431
2432         if ((rc = usb_register(&ub_driver)) != 0)
2433                 goto err_register;
2434
2435         usb_usual_set_present(USB_US_TYPE_UB);
2436         return 0;
2437
2438 err_register:
2439         unregister_blkdev(UB_MAJOR, DRV_NAME);
2440 err_regblkdev:
2441         return rc;
2442 }
2443
2444 static void __exit ub_exit(void)
2445 {
2446         usb_deregister(&ub_driver);
2447
2448         unregister_blkdev(UB_MAJOR, DRV_NAME);
2449         usb_usual_clear_present(USB_US_TYPE_UB);
2450 }
2451
2452 module_init(ub_init);
2453 module_exit(ub_exit);
2454
2455 MODULE_LICENSE("GPL");