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  *  -- special case some senses, e.g. 3a/0 -> no media present, reduce retries
  14  *  -- verify the 13 conditions and do bulk resets
  15  *  -- kill last_pipe and simply do two-state clearing on both pipes
  16  *  -- highmem
  17  *  -- move top_sense and work_bcs into separate allocations (if they survive)
  18  *     for cache purists and esoteric architectures.
  19  *  -- Allocate structure for LUN 0 before the first ub_sync_tur, avoid NULL. ?
  20  *  -- prune comments, they are too volumnous
  21  *  -- Exterminate P3 printks
  22  *  -- Resove XXX's
  23  *  -- Redo "benh's retries", perhaps have spin-up code to handle them. V:D=?
  24  *  -- CLEAR, CLR2STS, CLRRS seem to be ripe for refactoring.
  25  */
  26 #include <linux/kernel.h>
  27 #include <linux/module.h>
  28 #include <linux/usb.h>
  29 #include <linux/usb_usual.h>
  30 #include <linux/blkdev.h>
  31 #include <linux/devfs_fs_kernel.h>
  32 #include <linux/timer.h>
  33 #include <scsi/scsi.h>
  34
  35 #define DRV_NAME "ub"
  36 #define DEVFS_NAME DRV_NAME
  37
  38 #define UB_MAJOR 180
  39
  40 /*
  41  * The command state machine is the key model for understanding of this driver.
  42  *
  43  * The general rule is that all transitions are done towards the bottom
  44  * of the diagram, thus preventing any loops.
  45  *
  46  * An exception to that is how the STAT state is handled. A counter allows it
  47  * to be re-entered along the path marked with [C].
  48  *
  49  *       +--------+
  50  *       ! INIT   !
  51  *       +--------+
  52  *           !
  53  *        ub_scsi_cmd_start fails ->--------------------------------------\
  54  *           !                                                            !
  55  *           V                                                            !
  56  *       +--------+                                                       !
  57  *       ! CMD    !                                                       !
  58  *       +--------+                                                       !
  59  *           !                                            +--------+      !
  60  *         was -EPIPE -->-------------------------------->! CLEAR  !      !
  61  *           !                                            +--------+      !
  62  *           !                                                !           !
  63  *         was error -->------------------------------------- ! --------->\
  64  *           !                                                !           !
  65  *  /--<-- cmd->dir == NONE ?                                 !           !
  66  *  !        !                                                !           !
  67  *  !        V                                                !           !
  68  *  !    +--------+                                           !           !
  69  *  !    ! DATA   !                                           !           !
  70  *  !    +--------+                                           !           !
  71  *  !        !                           +---------+          !           !
  72  *  !      was -EPIPE -->--------------->! CLR2STS !          !           !
  73  *  !        !                           +---------+          !           !
  74  *  !        !                                !               !           !
  75  *  !        !                              was error -->---- ! --------->\
  76  *  !      was error -->--------------------- ! ------------- ! --------->\
  77  *  !        !                                !               !           !
  78  *  !        V                                !               !           !
  79  *  \--->+--------+                           !               !           !
  80  *       ! STAT   !<--------------------------/               !           !
  81  *  /--->+--------+                                           !           !
  82  *  !        !                                                !           !
  83  * [C]     was -EPIPE -->-----------\                         !           !
  84  *  !        !                      !                         !           !
  85  *  +<---- len == 0                 !                         !           !
  86  *  !        !                      !                         !           !
  87  *  !      was error -->--------------------------------------!---------->\
  88  *  !        !                      !                         !           !
  89  *  +<---- bad CSW                  !                         !           !
  90  *  +<---- bad tag                  !                         !           !
  91  *  !        !                      V                         !           !
  92  *  !        !                 +--------+                     !           !
  93  *  !        !                 ! CLRRS  !                     !           !
  94  *  !        !                 +--------+                     !           !
  95  *  !        !                      !                         !           !
  96  *  \------- ! --------------------[C]--------\               !           !
  97  *           !                                !               !           !
  98  *         cmd->error---\                +--------+           !           !
  99  *           !          +--------------->! SENSE  !<----------/           !
 100  *         STAT_FAIL----/                +--------+                       !
 101  *           !                                !                           V
 102  *           !                                V                      +--------+
 103  *           \--------------------------------\--------------------->! DONE   !
 104  *                                                                   +--------+
 105  */
 106
 107 /*
 108  * This many LUNs per USB device.
 109  * Every one of them takes a host, see UB_MAX_HOSTS.
 110  */
 111 #define UB_MAX_LUNS   9
 112
 113 /*
 114  */
 115
 116 #define UB_PARTS_PER_LUN      8
 117
 118 #define UB_MAX_CDB_SIZE      16         /* Corresponds to Bulk */
 119
 120 #define UB_SENSE_SIZE  18
 121
 122 /*
 123  */
 124
 125 /* command block wrapper */
 126 struct bulk_cb_wrap {
 127         __le32  Signature;              /* contains 'USBC' */
 128         u32     Tag;                    /* unique per command id */
 129         __le32  DataTransferLength;     /* size of data */
 130         u8      Flags;                  /* direction in bit 0 */
 131         u8      Lun;                    /* LUN */
 132         u8      Length;                 /* of of the CDB */
 133         u8      CDB[UB_MAX_CDB_SIZE];   /* max command */
 134 };
 135
 136 #define US_BULK_CB_WRAP_LEN     31
 137 #define US_BULK_CB_SIGN         0x43425355      /*spells out USBC */
 138 #define US_BULK_FLAG_IN         1
 139 #define US_BULK_FLAG_OUT        0
 140
 141 /* command status wrapper */
 142 struct bulk_cs_wrap {
 143         __le32  Signature;              /* should = 'USBS' */
 144         u32     Tag;                    /* same as original command */
 145         __le32  Residue;                /* amount not transferred */
 146         u8      Status;                 /* see below */
 147 };
 148
 149 #define US_BULK_CS_WRAP_LEN     13
 150 #define US_BULK_CS_SIGN         0x53425355      /* spells out 'USBS' */
 151 #define US_BULK_STAT_OK         0
 152 #define US_BULK_STAT_FAIL       1
 153 #define US_BULK_STAT_PHASE      2
 154
 155 /* bulk-only class specific requests */
 156 #define US_BULK_RESET_REQUEST   0xff
 157 #define US_BULK_GET_MAX_LUN     0xfe
 158
 159 /*
 160  */
 161 struct ub_dev;
 162
 163 #define UB_MAX_REQ_SG   9       /* cdrecord requires 32KB and maybe a header */
 164 #define UB_MAX_SECTORS 64
 165
 166 /*
 167  * A second is more than enough for a 32K transfer (UB_MAX_SECTORS)
 168  * even if a webcam hogs the bus, but some devices need time to spin up.
 169  */
 170 #define UB_URB_TIMEOUT  (HZ*2)
 171 #define UB_DATA_TIMEOUT (HZ*5)  /* ZIP does spin-ups in the data phase */
 172 #define UB_STAT_TIMEOUT (HZ*5)  /* Same spinups and eject for a dataless cmd. */
 173 #define UB_CTRL_TIMEOUT (HZ/2)  /* 500ms ought to be enough to clear a stall */
 174
 175 /*
 176  * An instance of a SCSI command in transit.
 177  */
 178 #define UB_DIR_NONE     0
 179 #define UB_DIR_READ     1
 180 #define UB_DIR_ILLEGAL2 2
 181 #define UB_DIR_WRITE    3
 182
 183 /* P3 */
 184 #define UB_DIR_CHAR(c)  (((c)==UB_DIR_WRITE)? 'w': \
 185                          (((c)==UB_DIR_READ)? 'r': 'n'))
 186
 187 enum ub_scsi_cmd_state {
 188         UB_CMDST_INIT,                  /* Initial state */
 189         UB_CMDST_CMD,                   /* Command submitted */
 190         UB_CMDST_DATA,                  /* Data phase */
 191         UB_CMDST_CLR2STS,               /* Clearing before requesting status */
 192         UB_CMDST_STAT,                  /* Status phase */
 193         UB_CMDST_CLEAR,                 /* Clearing a stall (halt, actually) */
 194         UB_CMDST_CLRRS,                 /* Clearing before retrying status */
 195         UB_CMDST_SENSE,                 /* Sending Request Sense */
 196         UB_CMDST_DONE                   /* Final state */
 197 };
 198
 199 struct ub_scsi_cmd {
 200         unsigned char cdb[UB_MAX_CDB_SIZE];
 201         unsigned char cdb_len;
 202
 203         unsigned char dir;              /* 0 - none, 1 - read, 3 - write. */
 204         enum ub_scsi_cmd_state state;
 205         unsigned int tag;
 206         struct ub_scsi_cmd *next;
 207
 208         int error;                      /* Return code - valid upon done */
 209         unsigned int act_len;           /* Return size */
 210         unsigned char key, asc, ascq;   /* May be valid if error==-EIO */
 211
 212         int stat_count;                 /* Retries getting status. */
 213
 214         unsigned int len;               /* Requested length */
 215         unsigned int current_sg;
 216         unsigned int nsg;               /* sgv[nsg] */
 217         struct scatterlist sgv[UB_MAX_REQ_SG];
 218
 219         struct ub_lun *lun;
 220         void (*done)(struct ub_dev *, struct ub_scsi_cmd *);
 221         void *back;
 222 };
 223
 224 struct ub_request {
 225         struct request *rq;
 226         unsigned int current_try;
 227         unsigned int nsg;               /* sgv[nsg] */
 228         struct scatterlist sgv[UB_MAX_REQ_SG];
 229 };
 230
 231 /*
 232  */
 233 struct ub_capacity {
 234         unsigned long nsec;             /* Linux size - 512 byte sectors */
 235         unsigned int bsize;             /* Linux hardsect_size */
 236         unsigned int bshift;            /* Shift between 512 and hard sects */
 237 };
 238
 239 /*
 240  * This is a direct take-off from linux/include/completion.h
 241  * The difference is that I do not wait on this thing, just poll.
 242  * When I want to wait (ub_probe), I just use the stock completion.
 243  *
 244  * Note that INIT_COMPLETION takes no lock. It is correct. But why
 245  * in the bloody hell that thing takes struct instead of pointer to struct
 246  * is quite beyond me. I just copied it from the stock completion.
 247  */
 248 struct ub_completion {
 249         unsigned int done;
 250         spinlock_t lock;
 251 };
 252
 253 static inline void ub_init_completion(struct ub_completion *x)
 254 {
 255         x->done = 0;
 256         spin_lock_init(&x->lock);
 257 }
 258
 259 #define UB_INIT_COMPLETION(x)   ((x).done = 0)
 260
 261 static void ub_complete(struct ub_completion *x)
 262 {
 263         unsigned long flags;
 264
 265         spin_lock_irqsave(&x->lock, flags);
 266         x->done++;
 267         spin_unlock_irqrestore(&x->lock, flags);
 268 }
 269
 270 static int ub_is_completed(struct ub_completion *x)
 271 {
 272         unsigned long flags;
 273         int ret;
 274
 275         spin_lock_irqsave(&x->lock, flags);
 276         ret = x->done;
 277         spin_unlock_irqrestore(&x->lock, flags);
 278         return ret;
 279 }
 280
 281 /*
 282  */
 283 struct ub_scsi_cmd_queue {
 284         int qlen, qmax;
 285         struct ub_scsi_cmd *head, *tail;
 286 };
 287
 288 /*
 289  * The block device instance (one per LUN).
 290  */
 291 struct ub_lun {
 292         struct ub_dev *udev;
 293         struct list_head link;
 294         struct gendisk *disk;
 295         int id;                         /* Host index */
 296         int num;                        /* LUN number */
 297         char name[16];
 298
 299         int changed;                    /* Media was changed */
 300         int removable;
 301         int readonly;
 302
 303         struct ub_request urq;
 304
 305         /* Use Ingo's mempool if or when we have more than one command. */
 306         /*
 307          * Currently we never need more than one command for the whole device.
 308          * However, giving every LUN a command is a cheap and automatic way
 309          * to enforce fairness between them.
 310          */
 311         int cmda[1];
 312         struct ub_scsi_cmd cmdv[1];
 313
 314         struct ub_capacity capacity;
 315 };
 316
 317 /*
 318  * The USB device instance.
 319  */
 320 struct ub_dev {
 321         spinlock_t *lock;
 322         atomic_t poison;                /* The USB device is disconnected */
 323         int openc;                      /* protected by ub_lock! */
 324                                         /* kref is too implicit for our taste */
 325         int reset;                      /* Reset is running */
 326         unsigned int tagcnt;
 327         char name[12];
 328         struct usb_device *dev;
 329         struct usb_interface *intf;
 330
 331         struct list_head luns;
 332
 333         unsigned int send_bulk_pipe;    /* cached pipe values */
 334         unsigned int recv_bulk_pipe;
 335         unsigned int send_ctrl_pipe;
 336         unsigned int recv_ctrl_pipe;
 337
 338         struct tasklet_struct tasklet;
 339
 340         struct ub_scsi_cmd_queue cmd_queue;
 341         struct ub_scsi_cmd top_rqs_cmd; /* REQUEST SENSE */
 342         unsigned char top_sense[UB_SENSE_SIZE];
 343
 344         struct ub_completion work_done;
 345         struct urb work_urb;
 346         struct timer_list work_timer;
 347         int last_pipe;                  /* What might need clearing */
 348         __le32 signature;               /* Learned signature */
 349         struct bulk_cb_wrap work_bcb;
 350         struct bulk_cs_wrap work_bcs;
 351         struct usb_ctrlrequest work_cr;
 352
 353         struct work_struct reset_work;
 354         wait_queue_head_t reset_wait;
 355
 356         int sg_stat[6];
 357 };
 358
 359 /*
 360  */
 361 static void ub_cleanup(struct ub_dev *sc);
 362 static int ub_request_fn_1(struct ub_lun *lun, struct request *rq);
 363 static void ub_cmd_build_block(struct ub_dev *sc, struct ub_lun *lun,
 364     struct ub_scsi_cmd *cmd, struct ub_request *urq);
 365 static void ub_cmd_build_packet(struct ub_dev *sc, struct ub_lun *lun,
 366     struct ub_scsi_cmd *cmd, struct ub_request *urq);
 367 static void ub_rw_cmd_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 368 static void ub_end_rq(struct request *rq, int uptodate);
 369 static int ub_rw_cmd_retry(struct ub_dev *sc, struct ub_lun *lun,
 370     struct ub_request *urq, struct ub_scsi_cmd *cmd);
 371 static int ub_submit_scsi(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 372 static void ub_urb_complete(struct urb *urb, struct pt_regs *pt);
 373 static void ub_scsi_action(unsigned long _dev);
 374 static void ub_scsi_dispatch(struct ub_dev *sc);
 375 static void ub_scsi_urb_compl(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 376 static void ub_data_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 377 static void ub_state_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd, int rc);
 378 static int __ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 379 static void ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 380 static void ub_state_stat_counted(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 381 static void ub_state_sense(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 382 static int ub_submit_clear_stall(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
 383     int stalled_pipe);
 384 static void ub_top_sense_done(struct ub_dev *sc, struct ub_scsi_cmd *scmd);
 385 static void ub_reset_enter(struct ub_dev *sc, int try);
 386 static void ub_reset_task(void *arg);
 387 static int ub_sync_tur(struct ub_dev *sc, struct ub_lun *lun);
 388 static int ub_sync_read_cap(struct ub_dev *sc, struct ub_lun *lun,
 389     struct ub_capacity *ret);
 390 static int ub_sync_reset(struct ub_dev *sc);
 391 static int ub_probe_clear_stall(struct ub_dev *sc, int stalled_pipe);
 392 static int ub_probe_lun(struct ub_dev *sc, int lnum);
 393
 394 /*
 395  */
 396 #ifdef CONFIG_USB_LIBUSUAL
 397
 398 #define ub_usb_ids  storage_usb_ids
 399 #else
 400
 401 static struct usb_device_id ub_usb_ids[] = {
 402         { USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, US_SC_SCSI, US_PR_BULK) },
 403         { }
 404 };
 405
 406 MODULE_DEVICE_TABLE(usb, ub_usb_ids);
 407 #endif /* CONFIG_USB_LIBUSUAL */
 408
 409 /*
 410  * Find me a way to identify "next free minor" for add_disk(),
 411  * and the array disappears the next day. However, the number of
 412  * hosts has something to do with the naming and /proc/partitions.
 413  * This has to be thought out in detail before changing.
 414  * If UB_MAX_HOST was 1000, we'd use a bitmap. Or a better data structure.
 415  */
 416 #define UB_MAX_HOSTS  26
 417 static char ub_hostv[UB_MAX_HOSTS];
 418
 419 #define UB_QLOCK_NUM 5
 420 static spinlock_t ub_qlockv[UB_QLOCK_NUM];
 421 static int ub_qlock_next = 0;
 422
 423 static DEFINE_SPINLOCK(ub_lock);        /* Locks globals and ->openc */
 424
 425 /*
 426  * The id allocator.
 427  *
 428  * This also stores the host for indexing by minor, which is somewhat dirty.
 429  */
 430 static int ub_id_get(void)
 431 {
 432         unsigned long flags;
 433         int i;
 434
 435         spin_lock_irqsave(&ub_lock, flags);
 436         for (i = 0; i < UB_MAX_HOSTS; i++) {
 437                 if (ub_hostv[i] == 0) {
 438                         ub_hostv[i] = 1;
 439                         spin_unlock_irqrestore(&ub_lock, flags);
 440                         return i;
 441                 }
 442         }
 443         spin_unlock_irqrestore(&ub_lock, flags);
 444         return -1;
 445 }
 446
 447 static void ub_id_put(int id)
 448 {
 449         unsigned long flags;
 450
 451         if (id < 0 || id >= UB_MAX_HOSTS) {
 452                 printk(KERN_ERR DRV_NAME ": bad host ID %d\n", id);
 453                 return;
 454         }
 455
 456         spin_lock_irqsave(&ub_lock, flags);
 457         if (ub_hostv[id] == 0) {
 458                 spin_unlock_irqrestore(&ub_lock, flags);
 459                 printk(KERN_ERR DRV_NAME ": freeing free host ID %d\n", id);
 460                 return;
 461         }
 462         ub_hostv[id] = 0;
 463         spin_unlock_irqrestore(&ub_lock, flags);
 464 }
 465
 466 /*
 467  * This is necessitated by the fact that blk_cleanup_queue does not
 468  * necesserily destroy the queue. Instead, it may merely decrease q->refcnt.
 469  * Since our blk_init_queue() passes a spinlock common with ub_dev,
 470  * we have life time issues when ub_cleanup frees ub_dev.
 471  */
 472 static spinlock_t *ub_next_lock(void)
 473 {
 474         unsigned long flags;
 475         spinlock_t *ret;
 476
 477         spin_lock_irqsave(&ub_lock, flags);
 478         ret = &ub_qlockv[ub_qlock_next];
 479         ub_qlock_next = (ub_qlock_next + 1) % UB_QLOCK_NUM;
 480         spin_unlock_irqrestore(&ub_lock, flags);
 481         return ret;
 482 }
 483
 484 /*
 485  * Downcount for deallocation. This rides on two assumptions:
 486  *  - once something is poisoned, its refcount cannot grow
 487  *  - opens cannot happen at this time (del_gendisk was done)
 488  * If the above is true, we can drop the lock, which we need for
 489  * blk_cleanup_queue(): the silly thing may attempt to sleep.
 490  * [Actually, it never needs to sleep for us, but it calls might_sleep()]
 491  */
 492 static void ub_put(struct ub_dev *sc)
 493 {
 494         unsigned long flags;
 495
 496         spin_lock_irqsave(&ub_lock, flags);
 497         --sc->openc;
 498         if (sc->openc == 0 && atomic_read(&sc->poison)) {
 499                 spin_unlock_irqrestore(&ub_lock, flags);
 500                 ub_cleanup(sc);
 501         } else {
 502                 spin_unlock_irqrestore(&ub_lock, flags);
 503         }
 504 }
 505
 506 /*
 507  * Final cleanup and deallocation.
 508  */
 509 static void ub_cleanup(struct ub_dev *sc)
 510 {
 511         struct list_head *p;
 512         struct ub_lun *lun;
 513         request_queue_t *q;
 514
 515         while (!list_empty(&sc->luns)) {
 516                 p = sc->luns.next;
 517                 lun = list_entry(p, struct ub_lun, link);
 518                 list_del(p);
 519
 520                 /* I don't think queue can be NULL. But... Stolen from sx8.c */
 521                 if ((q = lun->disk->queue) != NULL)
 522                         blk_cleanup_queue(q);
 523                 /*
 524                  * If we zero disk->private_data BEFORE put_disk, we have
 525                  * to check for NULL all over the place in open, release,
 526                  * check_media and revalidate, because the block level
 527                  * semaphore is well inside the put_disk.
 528                  * But we cannot zero after the call, because *disk is gone.
 529                  * The sd.c is blatantly racy in this area.
 530                  */
 531                 /* disk->private_data = NULL; */
 532                 put_disk(lun->disk);
 533                 lun->disk = NULL;
 534
 535                 ub_id_put(lun->id);
 536                 kfree(lun);
 537         }
 538
 539         kfree(sc);
 540 }
 541
 542 /*
 543  * The "command allocator".
 544  */
 545 static struct ub_scsi_cmd *ub_get_cmd(struct ub_lun *lun)
 546 {
 547         struct ub_scsi_cmd *ret;
 548
 549         if (lun->cmda[0])
 550                 return NULL;
 551         ret = &lun->cmdv[0];
 552         lun->cmda[0] = 1;
 553         return ret;
 554 }
 555
 556 static void ub_put_cmd(struct ub_lun *lun, struct ub_scsi_cmd *cmd)
 557 {
 558         if (cmd != &lun->cmdv[0]) {
 559                 printk(KERN_WARNING "%s: releasing a foreign cmd %p\n",
 560                     lun->name, cmd);
 561                 return;
 562         }
 563         if (!lun->cmda[0]) {
 564                 printk(KERN_WARNING "%s: releasing a free cmd\n", lun->name);
 565                 return;
 566         }
 567         lun->cmda[0] = 0;
 568 }
 569
 570 /*
 571  * The command queue.
 572  */
 573 static void ub_cmdq_add(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 574 {
 575         struct ub_scsi_cmd_queue *t = &sc->cmd_queue;
 576
 577         if (t->qlen++ == 0) {
 578                 t->head = cmd;
 579                 t->tail = cmd;
 580         } else {
 581                 t->tail->next = cmd;
 582                 t->tail = cmd;
 583         }
 584
 585         if (t->qlen > t->qmax)
 586                 t->qmax = t->qlen;
 587 }
 588
 589 static void ub_cmdq_insert(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 590 {
 591         struct ub_scsi_cmd_queue *t = &sc->cmd_queue;
 592
 593         if (t->qlen++ == 0) {
 594                 t->head = cmd;
 595                 t->tail = cmd;
 596         } else {
 597                 cmd->next = t->head;
 598                 t->head = cmd;
 599         }
 600
 601         if (t->qlen > t->qmax)
 602                 t->qmax = t->qlen;
 603 }
 604
 605 static struct ub_scsi_cmd *ub_cmdq_pop(struct ub_dev *sc)
 606 {
 607         struct ub_scsi_cmd_queue *t = &sc->cmd_queue;
 608         struct ub_scsi_cmd *cmd;
 609
 610         if (t->qlen == 0)
 611                 return NULL;
 612         if (--t->qlen == 0)
 613                 t->tail = NULL;
 614         cmd = t->head;
 615         t->head = cmd->next;
 616         cmd->next = NULL;
 617         return cmd;
 618 }
 619
 620 #define ub_cmdq_peek(sc)  ((sc)->cmd_queue.head)
 621
 622 /*
 623  * The request function is our main entry point
 624  */
 625
 626 static void ub_request_fn(request_queue_t *q)
 627 {
 628         struct ub_lun *lun = q->queuedata;
 629         struct request *rq;
 630
 631         while ((rq = elv_next_request(q)) != NULL) {
 632                 if (ub_request_fn_1(lun, rq) != 0) {
 633                         blk_stop_queue(q);
 634                         break;
 635                 }
 636         }
 637 }
 638
 639 static int ub_request_fn_1(struct ub_lun *lun, struct request *rq)
 640 {
 641         struct ub_dev *sc = lun->udev;
 642         struct ub_scsi_cmd *cmd;
 643         struct ub_request *urq;
 644         int n_elem;
 645
 646         if (atomic_read(&sc->poison) || lun->changed) {
 647                 blkdev_dequeue_request(rq);
 648                 ub_end_rq(rq, 0);
 649                 return 0;
 650         }
 651
 652         if (lun->urq.rq != NULL)
 653                 return -1;
 654         if ((cmd = ub_get_cmd(lun)) == NULL)
 655                 return -1;
 656         memset(cmd, 0, sizeof(struct ub_scsi_cmd));
 657
 658         blkdev_dequeue_request(rq);
 659
 660         urq = &lun->urq;
 661         memset(urq, 0, sizeof(struct ub_request));
 662         urq->rq = rq;
 663
 664         /*
 665          * get scatterlist from block layer
 666          */
 667         n_elem = blk_rq_map_sg(lun->disk->queue, rq, &urq->sgv[0]);
 668         if (n_elem < 0) {
 669                 printk(KERN_INFO "%s: failed request map (%d)\n",
 670                     lun->name, n_elem); /* P3 */
 671                 goto drop;
 672         }
 673         if (n_elem > UB_MAX_REQ_SG) {   /* Paranoia */
 674                 printk(KERN_WARNING "%s: request with %d segments\n",
 675                     lun->name, n_elem);
 676                 goto drop;
 677         }
 678         urq->nsg = n_elem;
 679         sc->sg_stat[n_elem < 5 ? n_elem : 5]++;
 680
 681         if (blk_pc_request(rq)) {
 682                 ub_cmd_build_packet(sc, lun, cmd, urq);
 683         } else {
 684                 ub_cmd_build_block(sc, lun, cmd, urq);
 685         }
 686         cmd->state = UB_CMDST_INIT;
 687         cmd->lun = lun;
 688         cmd->done = ub_rw_cmd_done;
 689         cmd->back = urq;
 690
 691         cmd->tag = sc->tagcnt++;
 692         if (ub_submit_scsi(sc, cmd) != 0)
 693                 goto drop;
 694
 695         return 0;
 696
 697 drop:
 698         ub_put_cmd(lun, cmd);
 699         ub_end_rq(rq, 0);
 700         return 0;
 701 }
 702
 703 static void ub_cmd_build_block(struct ub_dev *sc, struct ub_lun *lun,
 704     struct ub_scsi_cmd *cmd, struct ub_request *urq)
 705 {
 706         struct request *rq = urq->rq;
 707         unsigned int block, nblks;
 708
 709         if (rq_data_dir(rq) == WRITE)
 710                 cmd->dir = UB_DIR_WRITE;
 711         else
 712                 cmd->dir = UB_DIR_READ;
 713
 714         cmd->nsg = urq->nsg;
 715         memcpy(cmd->sgv, urq->sgv, sizeof(struct scatterlist) * cmd->nsg);
 716
 717         /*
 718          * build the command
 719          *
 720          * The call to blk_queue_hardsect_size() guarantees that request
 721          * is aligned, but it is given in terms of 512 byte units, always.
 722          */
 723         block = rq->sector >> lun->capacity.bshift;
 724         nblks = rq->nr_sectors >> lun->capacity.bshift;
 725
 726         cmd->cdb[0] = (cmd->dir == UB_DIR_READ)? READ_10: WRITE_10;
 727         /* 10-byte uses 4 bytes of LBA: 2147483648KB, 2097152MB, 2048GB */
 728         cmd->cdb[2] = block >> 24;
 729         cmd->cdb[3] = block >> 16;
 730         cmd->cdb[4] = block >> 8;
 731         cmd->cdb[5] = block;
 732         cmd->cdb[7] = nblks >> 8;
 733         cmd->cdb[8] = nblks;
 734         cmd->cdb_len = 10;
 735
 736         cmd->len = rq->nr_sectors * 512;
 737 }
 738
 739 static void ub_cmd_build_packet(struct ub_dev *sc, struct ub_lun *lun,
 740     struct ub_scsi_cmd *cmd, struct ub_request *urq)
 741 {
 742         struct request *rq = urq->rq;
 743
 744         if (rq->data_len == 0) {
 745                 cmd->dir = UB_DIR_NONE;
 746         } else {
 747                 if (rq_data_dir(rq) == WRITE)
 748                         cmd->dir = UB_DIR_WRITE;
 749                 else
 750                         cmd->dir = UB_DIR_READ;
 751         }
 752
 753         cmd->nsg = urq->nsg;
 754         memcpy(cmd->sgv, urq->sgv, sizeof(struct scatterlist) * cmd->nsg);
 755
 756         memcpy(&cmd->cdb, rq->cmd, rq->cmd_len);
 757         cmd->cdb_len = rq->cmd_len;
 758
 759         cmd->len = rq->data_len;
 760 }
 761
 762 static void ub_rw_cmd_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 763 {
 764         struct ub_lun *lun = cmd->lun;
 765         struct ub_request *urq = cmd->back;
 766         struct request *rq;
 767         int uptodate;
 768
 769         rq = urq->rq;
 770
 771         if (cmd->error == 0) {
 772                 uptodate = 1;
 773
 774                 if (blk_pc_request(rq)) {
 775                         if (cmd->act_len >= rq->data_len)
 776                                 rq->data_len = 0;
 777                         else
 778                                 rq->data_len -= cmd->act_len;
 779                 }
 780         } else {
 781                 uptodate = 0;
 782
 783                 if (blk_pc_request(rq)) {
 784                         /* UB_SENSE_SIZE is smaller than SCSI_SENSE_BUFFERSIZE */
 785                         memcpy(rq->sense, sc->top_sense, UB_SENSE_SIZE);
 786                         rq->sense_len = UB_SENSE_SIZE;
 787                         if (sc->top_sense[0] != 0)
 788                                 rq->errors = SAM_STAT_CHECK_CONDITION;
 789                         else
 790                                 rq->errors = DID_ERROR << 16;
 791                 } else {
 792                         if (cmd->error == -EIO) {
 793                                 if (ub_rw_cmd_retry(sc, lun, urq, cmd) == 0)
 794                                         return;
 795                         }
 796                 }
 797         }
 798
 799         urq->rq = NULL;
 800
 801         ub_put_cmd(lun, cmd);
 802         ub_end_rq(rq, uptodate);
 803         blk_start_queue(lun->disk->queue);
 804 }
 805
 806 static void ub_end_rq(struct request *rq, int uptodate)
 807 {
 808         end_that_request_first(rq, uptodate, rq->hard_nr_sectors);
 809         end_that_request_last(rq, uptodate);
 810 }
 811
 812 static int ub_rw_cmd_retry(struct ub_dev *sc, struct ub_lun *lun,
 813     struct ub_request *urq, struct ub_scsi_cmd *cmd)
 814 {
 815
 816         if (atomic_read(&sc->poison))
 817                 return -ENXIO;
 818
 819         ub_reset_enter(sc, urq->current_try);
 820
 821         if (urq->current_try >= 3)
 822                 return -EIO;
 823         urq->current_try++;
 824         /* P3 */ printk("%s: dir %c len/act %d/%d "
 825             "[sense %x %02x %02x] retry %d\n",
 826             sc->name, UB_DIR_CHAR(cmd->dir), cmd->len, cmd->act_len,
 827             cmd->key, cmd->asc, cmd->ascq, urq->current_try);
 828
 829         memset(cmd, 0, sizeof(struct ub_scsi_cmd));
 830         ub_cmd_build_block(sc, lun, cmd, urq);
 831
 832         cmd->state = UB_CMDST_INIT;
 833         cmd->lun = lun;
 834         cmd->done = ub_rw_cmd_done;
 835         cmd->back = urq;
 836
 837         cmd->tag = sc->tagcnt++;
 838
 839 #if 0 /* Wasteful */
 840         return ub_submit_scsi(sc, cmd);
 841 #else
 842         ub_cmdq_add(sc, cmd);
 843         return 0;
 844 #endif
 845 }
 846
 847 /*
 848  * Submit a regular SCSI operation (not an auto-sense).
 849  *
 850  * The Iron Law of Good Submit Routine is:
 851  * Zero return - callback is done, Nonzero return - callback is not done.
 852  * No exceptions.
 853  *
 854  * Host is assumed locked.
 855  */
 856 static int ub_submit_scsi(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 857 {
 858
 859         if (cmd->state != UB_CMDST_INIT ||
 860             (cmd->dir != UB_DIR_NONE && cmd->len == 0)) {
 861                 return -EINVAL;
 862         }
 863
 864         ub_cmdq_add(sc, cmd);
 865         /*
 866          * We can call ub_scsi_dispatch(sc) right away here, but it's a little
 867          * safer to jump to a tasklet, in case upper layers do something silly.
 868          */
 869         tasklet_schedule(&sc->tasklet);
 870         return 0;
 871 }
 872
 873 /*
 874  * Submit the first URB for the queued command.
 875  * This function does not deal with queueing in any way.
 876  */
 877 static int ub_scsi_cmd_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 878 {
 879         struct bulk_cb_wrap *bcb;
 880         int rc;
 881
 882         bcb = &sc->work_bcb;
 883
 884         /*
 885          * ``If the allocation length is eighteen or greater, and a device
 886          * server returns less than eithteen bytes of data, the application
 887          * client should assume that the bytes not transferred would have been
 888          * zeroes had the device server returned those bytes.''
 889          *
 890          * We zero sense for all commands so that when a packet request
 891          * fails it does not return a stale sense.
 892          */
 893         memset(&sc->top_sense, 0, UB_SENSE_SIZE);
 894
 895         /* set up the command wrapper */
 896         bcb->Signature = cpu_to_le32(US_BULK_CB_SIGN);
 897         bcb->Tag = cmd->tag;            /* Endianness is not important */
 898         bcb->DataTransferLength = cpu_to_le32(cmd->len);
 899         bcb->Flags = (cmd->dir == UB_DIR_READ) ? 0x80 : 0;
 900         bcb->Lun = (cmd->lun != NULL) ? cmd->lun->num : 0;
 901         bcb->Length = cmd->cdb_len;
 902
 903         /* copy the command payload */
 904         memcpy(bcb->CDB, cmd->cdb, UB_MAX_CDB_SIZE);
 905
 906         UB_INIT_COMPLETION(sc->work_done);
 907
 908         sc->last_pipe = sc->send_bulk_pipe;
 909         usb_fill_bulk_urb(&sc->work_urb, sc->dev, sc->send_bulk_pipe,
 910             bcb, US_BULK_CB_WRAP_LEN, ub_urb_complete, sc);
 911
 912         /* Fill what we shouldn't be filling, because usb-storage did so. */
 913         sc->work_urb.actual_length = 0;
 914         sc->work_urb.error_count = 0;
 915         sc->work_urb.status = 0;
 916
 917         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
 918                 /* XXX Clear stalls */
 919                 ub_complete(&sc->work_done);
 920                 return rc;
 921         }
 922
 923         sc->work_timer.expires = jiffies + UB_URB_TIMEOUT;
 924         add_timer(&sc->work_timer);
 925
 926         cmd->state = UB_CMDST_CMD;
 927         return 0;
 928 }
 929
 930 /*
 931  * Timeout handler.
 932  */
 933 static void ub_urb_timeout(unsigned long arg)
 934 {
 935         struct ub_dev *sc = (struct ub_dev *) arg;
 936         unsigned long flags;
 937
 938         spin_lock_irqsave(sc->lock, flags);
 939         if (!ub_is_completed(&sc->work_done))
 940                 usb_unlink_urb(&sc->work_urb);
 941         spin_unlock_irqrestore(sc->lock, flags);
 942 }
 943
 944 /*
 945  * Completion routine for the work URB.
 946  *
 947  * This can be called directly from usb_submit_urb (while we have
 948  * the sc->lock taken) and from an interrupt (while we do NOT have
 949  * the sc->lock taken). Therefore, bounce this off to a tasklet.
 950  */
 951 static void ub_urb_complete(struct urb *urb, struct pt_regs *pt)
 952 {
 953         struct ub_dev *sc = urb->context;
 954
 955         ub_complete(&sc->work_done);
 956         tasklet_schedule(&sc->tasklet);
 957 }
 958
 959 static void ub_scsi_action(unsigned long _dev)
 960 {
 961         struct ub_dev *sc = (struct ub_dev *) _dev;
 962         unsigned long flags;
 963
 964         spin_lock_irqsave(sc->lock, flags);
 965         ub_scsi_dispatch(sc);
 966         spin_unlock_irqrestore(sc->lock, flags);
 967 }
 968
 969 static void ub_scsi_dispatch(struct ub_dev *sc)
 970 {
 971         struct ub_scsi_cmd *cmd;
 972         int rc;
 973
 974         while (!sc->reset && (cmd = ub_cmdq_peek(sc)) != NULL) {
 975                 if (cmd->state == UB_CMDST_DONE) {
 976                         ub_cmdq_pop(sc);
 977                         (*cmd->done)(sc, cmd);
 978                 } else if (cmd->state == UB_CMDST_INIT) {
 979                         if ((rc = ub_scsi_cmd_start(sc, cmd)) == 0)
 980                                 break;
 981                         cmd->error = rc;
 982                         cmd->state = UB_CMDST_DONE;
 983                 } else {
 984                         if (!ub_is_completed(&sc->work_done))
 985                                 break;
 986                         del_timer(&sc->work_timer);
 987                         ub_scsi_urb_compl(sc, cmd);
 988                 }
 989         }
 990 }
 991
 992 static void ub_scsi_urb_compl(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 993 {
 994         struct urb *urb = &sc->work_urb;
 995         struct bulk_cs_wrap *bcs;
 996         int len;
 997         int rc;
 998
 999         if (atomic_read(&sc->poison)) {
1000                 ub_state_done(sc, cmd, -ENODEV);
1001                 return;
1002         }
1003
1004         if (cmd->state == UB_CMDST_CLEAR) {
1005                 if (urb->status == -EPIPE) {
1006                         /*
1007                          * STALL while clearning STALL.
1008                          * The control pipe clears itself - nothing to do.
1009                          */
1010                         printk(KERN_NOTICE "%s: stall on control pipe\n",
1011                             sc->name);
1012                         goto Bad_End;
1013                 }
1014
1015                 /*
1016                  * We ignore the result for the halt clear.
1017                  */
1018
1019                 /* reset the endpoint toggle */
1020                 usb_settoggle(sc->dev, usb_pipeendpoint(sc->last_pipe),
1021                         usb_pipeout(sc->last_pipe), 0);
1022
1023                 ub_state_sense(sc, cmd);
1024
1025         } else if (cmd->state == UB_CMDST_CLR2STS) {
1026                 if (urb->status == -EPIPE) {
1027                         printk(KERN_NOTICE "%s: stall on control pipe\n",
1028                             sc->name);
1029                         goto Bad_End;
1030                 }
1031
1032                 /*
1033                  * We ignore the result for the halt clear.
1034                  */
1035
1036                 /* reset the endpoint toggle */
1037                 usb_settoggle(sc->dev, usb_pipeendpoint(sc->last_pipe),
1038                         usb_pipeout(sc->last_pipe), 0);
1039
1040                 ub_state_stat(sc, cmd);
1041
1042         } else if (cmd->state == UB_CMDST_CLRRS) {
1043                 if (urb->status == -EPIPE) {
1044                         printk(KERN_NOTICE "%s: stall on control pipe\n",
1045                             sc->name);
1046                         goto Bad_End;
1047                 }
1048
1049                 /*
1050                  * We ignore the result for the halt clear.
1051                  */
1052
1053                 /* reset the endpoint toggle */
1054                 usb_settoggle(sc->dev, usb_pipeendpoint(sc->last_pipe),
1055                         usb_pipeout(sc->last_pipe), 0);
1056
1057                 ub_state_stat_counted(sc, cmd);
1058
1059         } else if (cmd->state == UB_CMDST_CMD) {
1060                 switch (urb->status) {
1061                 case 0:
1062                         break;
1063                 case -EOVERFLOW:
1064                         goto Bad_End;
1065                 case -EPIPE:
1066                         rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
1067                         if (rc != 0) {
1068                                 printk(KERN_NOTICE "%s: "
1069                                     "unable to submit clear (%d)\n",
1070                                     sc->name, rc);
1071                                 /*
1072                                  * This is typically ENOMEM or some other such shit.
1073                                  * Retrying is pointless. Just do Bad End on it...
1074                                  */
1075                                 ub_state_done(sc, cmd, rc);
1076                                 return;
1077                         }
1078                         cmd->state = UB_CMDST_CLEAR;
1079                         return;
1080                 case -ESHUTDOWN:        /* unplug */
1081                 case -EILSEQ:           /* unplug timeout on uhci */
1082                         ub_state_done(sc, cmd, -ENODEV);
1083                         return;
1084                 default:
1085                         goto Bad_End;
1086                 }
1087                 if (urb->actual_length != US_BULK_CB_WRAP_LEN) {
1088                         goto Bad_End;
1089                 }
1090
1091                 if (cmd->dir == UB_DIR_NONE || cmd->nsg < 1) {
1092                         ub_state_stat(sc, cmd);
1093                         return;
1094                 }
1095
1096                 // udelay(125);         // usb-storage has this
1097                 ub_data_start(sc, cmd);
1098
1099         } else if (cmd->state == UB_CMDST_DATA) {
1100                 if (urb->status == -EPIPE) {
1101                         rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
1102                         if (rc != 0) {
1103                                 printk(KERN_NOTICE "%s: "
1104                                     "unable to submit clear (%d)\n",
1105                                     sc->name, rc);
1106                                 ub_state_done(sc, cmd, rc);
1107                                 return;
1108                         }
1109                         cmd->state = UB_CMDST_CLR2STS;
1110                         return;
1111                 }
1112                 if (urb->status == -EOVERFLOW) {
1113                         /*
1114                          * A babble? Failure, but we must transfer CSW now.
1115                          */
1116                         cmd->error = -EOVERFLOW;        /* A cheap trick... */
1117                         ub_state_stat(sc, cmd);
1118                         return;
1119                 }
1120
1121                 if (cmd->dir == UB_DIR_WRITE) {
1122                         /*
1123                          * Do not continue writes in case of a failure.
1124                          * Doing so would cause sectors to be mixed up,
1125                          * which is worse than sectors lost.
1126                          *
1127                          * We must try to read the CSW, or many devices
1128                          * get confused.
1129                          */
1130                         len = urb->actual_length;
1131                         if (urb->status != 0 ||
1132                             len != cmd->sgv[cmd->current_sg].length) {
1133                                 cmd->act_len += len;
1134
1135                                 cmd->error = -EIO;
1136                                 ub_state_stat(sc, cmd);
1137                                 return;
1138                         }
1139
1140                 } else {
1141                         /*
1142                          * If an error occurs on read, we record it, and
1143                          * continue to fetch data in order to avoid bubble.
1144                          *
1145                          * As a small shortcut, we stop if we detect that
1146                          * a CSW mixed into data.
1147                          */
1148                         if (urb->status != 0)
1149                                 cmd->error = -EIO;
1150
1151                         len = urb->actual_length;
1152                         if (urb->status != 0 ||
1153                             len != cmd->sgv[cmd->current_sg].length) {
1154                                 if ((len & 0x1FF) == US_BULK_CS_WRAP_LEN)
1155                                         goto Bad_End;
1156                         }
1157                 }
1158
1159                 cmd->act_len += urb->actual_length;
1160
1161                 if (++cmd->current_sg < cmd->nsg) {
1162                         ub_data_start(sc, cmd);
1163                         return;
1164                 }
1165                 ub_state_stat(sc, cmd);
1166
1167         } else if (cmd->state == UB_CMDST_STAT) {
1168                 if (urb->status == -EPIPE) {
1169                         rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
1170                         if (rc != 0) {
1171                                 printk(KERN_NOTICE "%s: "
1172                                     "unable to submit clear (%d)\n",
1173                                     sc->name, rc);
1174                                 ub_state_done(sc, cmd, rc);
1175                                 return;
1176                         }
1177
1178                         /*
1179                          * Having a stall when getting CSW is an error, so
1180                          * make sure uppper levels are not oblivious to it.
1181                          */
1182                         cmd->error = -EIO;              /* A cheap trick... */
1183
1184                         cmd->state = UB_CMDST_CLRRS;
1185                         return;
1186                 }
1187
1188                 /* Catch everything, including -EOVERFLOW and other nasties. */
1189                 if (urb->status != 0)
1190                         goto Bad_End;
1191
1192                 if (urb->actual_length == 0) {
1193                         ub_state_stat_counted(sc, cmd);
1194                         return;
1195                 }
1196
1197                 /*
1198                  * Check the returned Bulk protocol status.
1199                  * The status block has to be validated first.
1200                  */
1201
1202                 bcs = &sc->work_bcs;
1203
1204                 if (sc->signature == cpu_to_le32(0)) {
1205                         /*
1206                          * This is the first reply, so do not perform the check.
1207                          * Instead, remember the signature the device uses
1208                          * for future checks. But do not allow a nul.
1209                          */
1210                         sc->signature = bcs->Signature;
1211                         if (sc->signature == cpu_to_le32(0)) {
1212                                 ub_state_stat_counted(sc, cmd);
1213                                 return;
1214                         }
1215                 } else {
1216                         if (bcs->Signature != sc->signature) {
1217                                 ub_state_stat_counted(sc, cmd);
1218                                 return;
1219                         }
1220                 }
1221
1222                 if (bcs->Tag != cmd->tag) {
1223                         /*
1224                          * This usually happens when we disagree with the
1225                          * device's microcode about something. For instance,
1226                          * a few of them throw this after timeouts. They buffer
1227                          * commands and reply at commands we timed out before.
1228                          * Without flushing these replies we loop forever.
1229                          */
1230                         ub_state_stat_counted(sc, cmd);
1231                         return;
1232                 }
1233
1234                 len = le32_to_cpu(bcs->Residue);
1235                 if (len != cmd->len - cmd->act_len) {
1236                         /*
1237                          * It is all right to transfer less, the caller has
1238                          * to check. But it's not all right if the device
1239                          * counts disagree with our counts.
1240                          */
1241                         /* P3 */ printk("%s: resid %d len %d act %d\n",
1242                             sc->name, len, cmd->len, cmd->act_len);
1243                         goto Bad_End;
1244                 }
1245
1246                 switch (bcs->Status) {
1247                 case US_BULK_STAT_OK:
1248                         break;
1249                 case US_BULK_STAT_FAIL:
1250                         ub_state_sense(sc, cmd);
1251                         return;
1252                 case US_BULK_STAT_PHASE:
1253                         /* P3 */ printk("%s: status PHASE\n", sc->name);
1254                         goto Bad_End;
1255                 default:
1256                         printk(KERN_INFO "%s: unknown CSW status 0x%x\n",
1257                             sc->name, bcs->Status);
1258                         ub_state_done(sc, cmd, -EINVAL);
1259                         return;
1260                 }
1261
1262                 /* Not zeroing error to preserve a babble indicator */
1263                 if (cmd->error != 0) {
1264                         ub_state_sense(sc, cmd);
1265                         return;
1266                 }
1267                 cmd->state = UB_CMDST_DONE;
1268                 ub_cmdq_pop(sc);
1269                 (*cmd->done)(sc, cmd);
1270
1271         } else if (cmd->state == UB_CMDST_SENSE) {
1272                 ub_state_done(sc, cmd, -EIO);
1273
1274         } else {
1275                 printk(KERN_WARNING "%s: "
1276                     "wrong command state %d\n",
1277                     sc->name, cmd->state);
1278                 ub_state_done(sc, cmd, -EINVAL);
1279                 return;
1280         }
1281         return;
1282
1283 Bad_End: /* Little Excel is dead */
1284         ub_state_done(sc, cmd, -EIO);
1285 }
1286
1287 /*
1288  * Factorization helper for the command state machine:
1289  * Initiate a data segment transfer.
1290  */
1291 static void ub_data_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1292 {
1293         struct scatterlist *sg = &cmd->sgv[cmd->current_sg];
1294         int pipe;
1295         int rc;
1296
1297         UB_INIT_COMPLETION(sc->work_done);
1298
1299         if (cmd->dir == UB_DIR_READ)
1300                 pipe = sc->recv_bulk_pipe;
1301         else
1302                 pipe = sc->send_bulk_pipe;
1303         sc->last_pipe = pipe;
1304         usb_fill_bulk_urb(&sc->work_urb, sc->dev, pipe,
1305             page_address(sg->page) + sg->offset, sg->length,
1306             ub_urb_complete, sc);
1307         sc->work_urb.actual_length = 0;
1308         sc->work_urb.error_count = 0;
1309         sc->work_urb.status = 0;
1310
1311         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
1312                 /* XXX Clear stalls */
1313                 ub_complete(&sc->work_done);
1314                 ub_state_done(sc, cmd, rc);
1315                 return;
1316         }
1317
1318         sc->work_timer.expires = jiffies + UB_DATA_TIMEOUT;
1319         add_timer(&sc->work_timer);
1320
1321         cmd->state = UB_CMDST_DATA;
1322 }
1323
1324 /*
1325  * Factorization helper for the command state machine:
1326  * Finish the command.
1327  */
1328 static void ub_state_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd, int rc)
1329 {
1330
1331         cmd->error = rc;
1332         cmd->state = UB_CMDST_DONE;
1333         ub_cmdq_pop(sc);
1334         (*cmd->done)(sc, cmd);
1335 }
1336
1337 /*
1338  * Factorization helper for the command state machine:
1339  * Submit a CSW read.
1340  */
1341 static int __ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1342 {
1343         int rc;
1344
1345         UB_INIT_COMPLETION(sc->work_done);
1346
1347         sc->last_pipe = sc->recv_bulk_pipe;
1348         usb_fill_bulk_urb(&sc->work_urb, sc->dev, sc->recv_bulk_pipe,
1349             &sc->work_bcs, US_BULK_CS_WRAP_LEN, ub_urb_complete, sc);
1350         sc->work_urb.actual_length = 0;
1351         sc->work_urb.error_count = 0;
1352         sc->work_urb.status = 0;
1353
1354         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
1355                 /* XXX Clear stalls */
1356                 ub_complete(&sc->work_done);
1357                 ub_state_done(sc, cmd, rc);
1358                 return -1;
1359         }
1360
1361         sc->work_timer.expires = jiffies + UB_STAT_TIMEOUT;
1362         add_timer(&sc->work_timer);
1363         return 0;
1364 }
1365
1366 /*
1367  * Factorization helper for the command state machine:
1368  * Submit a CSW read and go to STAT state.
1369  */
1370 static void ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1371 {
1372
1373         if (__ub_state_stat(sc, cmd) != 0)
1374                 return;
1375
1376         cmd->stat_count = 0;
1377         cmd->state = UB_CMDST_STAT;
1378 }
1379
1380 /*
1381  * Factorization helper for the command state machine:
1382  * Submit a CSW read and go to STAT state with counter (along [C] path).
1383  */
1384 static void ub_state_stat_counted(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1385 {
1386
1387         if (++cmd->stat_count >= 4) {
1388                 ub_state_sense(sc, cmd);
1389                 return;
1390         }
1391
1392         if (__ub_state_stat(sc, cmd) != 0)
1393                 return;
1394
1395         cmd->state = UB_CMDST_STAT;
1396 }
1397
1398 /*
1399  * Factorization helper for the command state machine:
1400  * Submit a REQUEST SENSE and go to SENSE state.
1401  */
1402 static void ub_state_sense(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1403 {
1404         struct ub_scsi_cmd *scmd;
1405         struct scatterlist *sg;
1406         int rc;
1407
1408         if (cmd->cdb[0] == REQUEST_SENSE) {
1409                 rc = -EPIPE;
1410                 goto error;
1411         }
1412
1413         scmd = &sc->top_rqs_cmd;
1414         memset(scmd, 0, sizeof(struct ub_scsi_cmd));
1415         scmd->cdb[0] = REQUEST_SENSE;
1416         scmd->cdb[4] = UB_SENSE_SIZE;
1417         scmd->cdb_len = 6;
1418         scmd->dir = UB_DIR_READ;
1419         scmd->state = UB_CMDST_INIT;
1420         scmd->nsg = 1;
1421         sg = &scmd->sgv[0];
1422         sg->page = virt_to_page(sc->top_sense);
1423         sg->offset = (unsigned long)sc->top_sense & (PAGE_SIZE-1);
1424         sg->length = UB_SENSE_SIZE;
1425         scmd->len = UB_SENSE_SIZE;
1426         scmd->lun = cmd->lun;
1427         scmd->done = ub_top_sense_done;
1428         scmd->back = cmd;
1429
1430         scmd->tag = sc->tagcnt++;
1431
1432         cmd->state = UB_CMDST_SENSE;
1433
1434         ub_cmdq_insert(sc, scmd);
1435         return;
1436
1437 error:
1438         ub_state_done(sc, cmd, rc);
1439 }
1440
1441 /*
1442  * A helper for the command's state machine:
1443  * Submit a stall clear.
1444  */
1445 static int ub_submit_clear_stall(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
1446     int stalled_pipe)
1447 {
1448         int endp;
1449         struct usb_ctrlrequest *cr;
1450         int rc;
1451
1452         endp = usb_pipeendpoint(stalled_pipe);
1453         if (usb_pipein (stalled_pipe))
1454                 endp |= USB_DIR_IN;
1455
1456         cr = &sc->work_cr;
1457         cr->bRequestType = USB_RECIP_ENDPOINT;
1458         cr->bRequest = USB_REQ_CLEAR_FEATURE;
1459         cr->wValue = cpu_to_le16(USB_ENDPOINT_HALT);
1460         cr->wIndex = cpu_to_le16(endp);
1461         cr->wLength = cpu_to_le16(0);
1462
1463         UB_INIT_COMPLETION(sc->work_done);
1464
1465         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->send_ctrl_pipe,
1466             (unsigned char*) cr, NULL, 0, ub_urb_complete, sc);
1467         sc->work_urb.actual_length = 0;
1468         sc->work_urb.error_count = 0;
1469         sc->work_urb.status = 0;
1470
1471         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
1472                 ub_complete(&sc->work_done);
1473                 return rc;
1474         }
1475
1476         sc->work_timer.expires = jiffies + UB_CTRL_TIMEOUT;
1477         add_timer(&sc->work_timer);
1478         return 0;
1479 }
1480
1481 /*
1482  */
1483 static void ub_top_sense_done(struct ub_dev *sc, struct ub_scsi_cmd *scmd)
1484 {
1485         unsigned char *sense = sc->top_sense;
1486         struct ub_scsi_cmd *cmd;
1487
1488         /*
1489          * Find the command which triggered the unit attention or a check,
1490          * save the sense into it, and advance its state machine.
1491          */
1492         if ((cmd = ub_cmdq_peek(sc)) == NULL) {
1493                 printk(KERN_WARNING "%s: sense done while idle\n", sc->name);
1494                 return;
1495         }
1496         if (cmd != scmd->back) {
1497                 printk(KERN_WARNING "%s: "
1498                     "sense done for wrong command 0x%x\n",
1499                     sc->name, cmd->tag);
1500                 return;
1501         }
1502         if (cmd->state != UB_CMDST_SENSE) {
1503                 printk(KERN_WARNING "%s: "
1504                     "sense done with bad cmd state %d\n",
1505                     sc->name, cmd->state);
1506                 return;
1507         }
1508
1509         /*
1510          * Ignoring scmd->act_len, because the buffer was pre-zeroed.
1511          */
1512         cmd->key = sense[2] & 0x0F;
1513         cmd->asc = sense[12];
1514         cmd->ascq = sense[13];
1515
1516         ub_scsi_urb_compl(sc, cmd);
1517 }
1518
1519 /*
1520  * Reset management
1521  * XXX Move usb_reset_device to khubd. Hogging kevent is not a good thing.
1522  * XXX Make usb_sync_reset asynchronous.
1523  */
1524
1525 static void ub_reset_enter(struct ub_dev *sc, int try)
1526 {
1527
1528         if (sc->reset) {
1529                 /* This happens often on multi-LUN devices. */
1530                 return;
1531         }
1532         sc->reset = try + 1;
1533
1534 #if 0 /* Not needed because the disconnect waits for us. */
1535         unsigned long flags;
1536         spin_lock_irqsave(&ub_lock, flags);
1537         sc->openc++;
1538         spin_unlock_irqrestore(&ub_lock, flags);
1539 #endif
1540
1541 #if 0 /* We let them stop themselves. */
1542         struct list_head *p;
1543         struct ub_lun *lun;
1544         list_for_each(p, &sc->luns) {
1545                 lun = list_entry(p, struct ub_lun, link);
1546                 blk_stop_queue(lun->disk->queue);
1547         }
1548 #endif
1549
1550         schedule_work(&sc->reset_work);
1551 }
1552
1553 static void ub_reset_task(void *arg)
1554 {
1555         struct ub_dev *sc = arg;
1556         unsigned long flags;
1557         struct list_head *p;
1558         struct ub_lun *lun;
1559         int lkr, rc;
1560
1561         if (!sc->reset) {
1562                 printk(KERN_WARNING "%s: Running reset unrequested\n",
1563                     sc->name);
1564                 return;
1565         }
1566
1567         if (atomic_read(&sc->poison)) {
1568                 printk(KERN_NOTICE "%s: Not resetting disconnected device\n",
1569                     sc->name); /* P3 This floods. Remove soon. XXX */
1570         } else if ((sc->reset & 1) == 0) {
1571                 ub_sync_reset(sc);
1572                 msleep(700);    /* usb-storage sleeps 6s (!) */
1573                 ub_probe_clear_stall(sc, sc->recv_bulk_pipe);
1574                 ub_probe_clear_stall(sc, sc->send_bulk_pipe);
1575         } else if (sc->dev->actconfig->desc.bNumInterfaces != 1) {
1576                 printk(KERN_NOTICE "%s: Not resetting multi-interface device\n",
1577                     sc->name); /* P3 This floods. Remove soon. XXX */
1578         } else {
1579                 if ((lkr = usb_lock_device_for_reset(sc->dev, sc->intf)) < 0) {
1580                         printk(KERN_NOTICE
1581                             "%s: usb_lock_device_for_reset failed (%d)\n",
1582                             sc->name, lkr);
1583                 } else {
1584                         rc = usb_reset_device(sc->dev);
1585                         if (rc < 0) {
1586                                 printk(KERN_NOTICE "%s: "
1587                                     "usb_lock_device_for_reset failed (%d)\n",
1588                                     sc->name, rc);
1589                         }
1590
1591                         if (lkr)
1592                                 usb_unlock_device(sc->dev);
1593                 }
1594         }
1595
1596         /*
1597          * In theory, no commands can be running while reset is active,
1598          * so nobody can ask for another reset, and so we do not need any
1599          * queues of resets or anything. We do need a spinlock though,
1600          * to interact with block layer.
1601          */
1602         spin_lock_irqsave(sc->lock, flags);
1603         sc->reset = 0;
1604         tasklet_schedule(&sc->tasklet);
1605         list_for_each(p, &sc->luns) {
1606                 lun = list_entry(p, struct ub_lun, link);
1607                 blk_start_queue(lun->disk->queue);
1608         }
1609         wake_up(&sc->reset_wait);
1610         spin_unlock_irqrestore(sc->lock, flags);
1611 }
1612
1613 /*
1614  * This is called from a process context.
1615  */
1616 static void ub_revalidate(struct ub_dev *sc, struct ub_lun *lun)
1617 {
1618
1619         lun->readonly = 0;      /* XXX Query this from the device */
1620
1621         lun->capacity.nsec = 0;
1622         lun->capacity.bsize = 512;
1623         lun->capacity.bshift = 0;
1624
1625         if (ub_sync_tur(sc, lun) != 0)
1626                 return;                 /* Not ready */
1627         lun->changed = 0;
1628
1629         if (ub_sync_read_cap(sc, lun, &lun->capacity) != 0) {
1630                 /*
1631                  * The retry here means something is wrong, either with the
1632                  * device, with the transport, or with our code.
1633                  * We keep this because sd.c has retries for capacity.
1634                  */
1635                 if (ub_sync_read_cap(sc, lun, &lun->capacity) != 0) {
1636                         lun->capacity.nsec = 0;
1637                         lun->capacity.bsize = 512;
1638                         lun->capacity.bshift = 0;
1639                 }
1640         }
1641 }
1642
1643 /*
1644  * The open funcion.
1645  * This is mostly needed to keep refcounting, but also to support
1646  * media checks on removable media drives.
1647  */
1648 static int ub_bd_open(struct inode *inode, struct file *filp)
1649 {
1650         struct gendisk *disk = inode->i_bdev->bd_disk;
1651         struct ub_lun *lun;
1652         struct ub_dev *sc;
1653         unsigned long flags;
1654         int rc;
1655
1656         if ((lun = disk->private_data) == NULL)
1657                 return -ENXIO;
1658         sc = lun->udev;
1659
1660         spin_lock_irqsave(&ub_lock, flags);
1661         if (atomic_read(&sc->poison)) {
1662                 spin_unlock_irqrestore(&ub_lock, flags);
1663                 return -ENXIO;
1664         }
1665         sc->openc++;
1666         spin_unlock_irqrestore(&ub_lock, flags);
1667
1668         if (lun->removable || lun->readonly)
1669                 check_disk_change(inode->i_bdev);
1670
1671         /*
1672          * The sd.c considers ->media_present and ->changed not equivalent,
1673          * under some pretty murky conditions (a failure of READ CAPACITY).
1674          * We may need it one day.
1675          */
1676         if (lun->removable && lun->changed && !(filp->f_flags & O_NDELAY)) {
1677                 rc = -ENOMEDIUM;
1678                 goto err_open;
1679         }
1680
1681         if (lun->readonly && (filp->f_mode & FMODE_WRITE)) {
1682                 rc = -EROFS;
1683                 goto err_open;
1684         }
1685
1686         return 0;
1687
1688 err_open:
1689         ub_put(sc);
1690         return rc;
1691 }
1692
1693 /*
1694  */
1695 static int ub_bd_release(struct inode *inode, struct file *filp)
1696 {
1697         struct gendisk *disk = inode->i_bdev->bd_disk;
1698         struct ub_lun *lun = disk->private_data;
1699         struct ub_dev *sc = lun->udev;
1700
1701         ub_put(sc);
1702         return 0;
1703 }
1704
1705 /*
1706  * The ioctl interface.
1707  */
1708 static int ub_bd_ioctl(struct inode *inode, struct file *filp,
1709     unsigned int cmd, unsigned long arg)
1710 {
1711         struct gendisk *disk = inode->i_bdev->bd_disk;
1712         void __user *usermem = (void __user *) arg;
1713
1714         return scsi_cmd_ioctl(filp, disk, cmd, usermem);
1715 }
1716
1717 /*
1718  * This is called once a new disk was seen by the block layer or by ub_probe().
1719  * The main onjective here is to discover the features of the media such as
1720  * the capacity, read-only status, etc. USB storage generally does not
1721  * need to be spun up, but if we needed it, this would be the place.
1722  *
1723  * This call can sleep.
1724  *
1725  * The return code is not used.
1726  */
1727 static int ub_bd_revalidate(struct gendisk *disk)
1728 {
1729         struct ub_lun *lun = disk->private_data;
1730
1731         ub_revalidate(lun->udev, lun);
1732
1733         /* XXX Support sector size switching like in sr.c */
1734         blk_queue_hardsect_size(disk->queue, lun->capacity.bsize);
1735         set_capacity(disk, lun->capacity.nsec);
1736         // set_disk_ro(sdkp->disk, lun->readonly);
1737
1738         return 0;
1739 }
1740
1741 /*
1742  * The check is called by the block layer to verify if the media
1743  * is still available. It is supposed to be harmless, lightweight and
1744  * non-intrusive in case the media was not changed.
1745  *
1746  * This call can sleep.
1747  *
1748  * The return code is bool!
1749  */
1750 static int ub_bd_media_changed(struct gendisk *disk)
1751 {
1752         struct ub_lun *lun = disk->private_data;
1753
1754         if (!lun->removable)
1755                 return 0;
1756
1757         /*
1758          * We clean checks always after every command, so this is not
1759          * as dangerous as it looks. If the TEST_UNIT_READY fails here,
1760          * the device is actually not ready with operator or software
1761          * intervention required. One dangerous item might be a drive which
1762          * spins itself down, and come the time to write dirty pages, this
1763          * will fail, then block layer discards the data. Since we never
1764          * spin drives up, such devices simply cannot be used with ub anyway.
1765          */
1766         if (ub_sync_tur(lun->udev, lun) != 0) {
1767                 lun->changed = 1;
1768                 return 1;
1769         }
1770
1771         return lun->changed;
1772 }
1773
1774 static struct block_device_operations ub_bd_fops = {
1775         .owner          = THIS_MODULE,
1776         .open           = ub_bd_open,
1777         .release        = ub_bd_release,
1778         .ioctl          = ub_bd_ioctl,
1779         .media_changed  = ub_bd_media_changed,
1780         .revalidate_disk = ub_bd_revalidate,
1781 };
1782
1783 /*
1784  * Common ->done routine for commands executed synchronously.
1785  */
1786 static void ub_probe_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1787 {
1788         struct completion *cop = cmd->back;
1789         complete(cop);
1790 }
1791
1792 /*
1793  * Test if the device has a check condition on it, synchronously.
1794  */
1795 static int ub_sync_tur(struct ub_dev *sc, struct ub_lun *lun)
1796 {
1797         struct ub_scsi_cmd *cmd;
1798         enum { ALLOC_SIZE = sizeof(struct ub_scsi_cmd) };
1799         unsigned long flags;
1800         struct completion compl;
1801         int rc;
1802
1803         init_completion(&compl);
1804
1805         rc = -ENOMEM;
1806         if ((cmd = kzalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
1807                 goto err_alloc;
1808
1809         cmd->cdb[0] = TEST_UNIT_READY;
1810         cmd->cdb_len = 6;
1811         cmd->dir = UB_DIR_NONE;
1812         cmd->state = UB_CMDST_INIT;
1813         cmd->lun = lun;                 /* This may be NULL, but that's ok */
1814         cmd->done = ub_probe_done;
1815         cmd->back = &compl;
1816
1817         spin_lock_irqsave(sc->lock, flags);
1818         cmd->tag = sc->tagcnt++;
1819
1820         rc = ub_submit_scsi(sc, cmd);
1821         spin_unlock_irqrestore(sc->lock, flags);
1822
1823         if (rc != 0) {
1824                 printk("ub: testing ready: submit error (%d)\n", rc); /* P3 */
1825                 goto err_submit;
1826         }
1827
1828         wait_for_completion(&compl);
1829
1830         rc = cmd->error;
1831
1832         if (rc == -EIO && cmd->key != 0)        /* Retries for benh's key */
1833                 rc = cmd->key;
1834
1835 err_submit:
1836         kfree(cmd);
1837 err_alloc:
1838         return rc;
1839 }
1840
1841 /*
1842  * Read the SCSI capacity synchronously (for probing).
1843  */
1844 static int ub_sync_read_cap(struct ub_dev *sc, struct ub_lun *lun,
1845     struct ub_capacity *ret)
1846 {
1847         struct ub_scsi_cmd *cmd;
1848         struct scatterlist *sg;
1849         char *p;
1850         enum { ALLOC_SIZE = sizeof(struct ub_scsi_cmd) + 8 };
1851         unsigned long flags;
1852         unsigned int bsize, shift;
1853         unsigned long nsec;
1854         struct completion compl;
1855         int rc;
1856
1857         init_completion(&compl);
1858
1859         rc = -ENOMEM;
1860         if ((cmd = kzalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
1861                 goto err_alloc;
1862         p = (char *)cmd + sizeof(struct ub_scsi_cmd);
1863
1864         cmd->cdb[0] = 0x25;
1865         cmd->cdb_len = 10;
1866         cmd->dir = UB_DIR_READ;
1867         cmd->state = UB_CMDST_INIT;
1868         cmd->nsg = 1;
1869         sg = &cmd->sgv[0];
1870         sg->page = virt_to_page(p);
1871         sg->offset = (unsigned long)p & (PAGE_SIZE-1);
1872         sg->length = 8;
1873         cmd->len = 8;
1874         cmd->lun = lun;
1875         cmd->done = ub_probe_done;
1876         cmd->back = &compl;
1877
1878         spin_lock_irqsave(sc->lock, flags);
1879         cmd->tag = sc->tagcnt++;
1880
1881         rc = ub_submit_scsi(sc, cmd);
1882         spin_unlock_irqrestore(sc->lock, flags);
1883
1884         if (rc != 0) {
1885                 printk("ub: reading capacity: submit error (%d)\n", rc); /* P3 */
1886                 goto err_submit;
1887         }
1888
1889         wait_for_completion(&compl);
1890
1891         if (cmd->error != 0) {
1892                 printk("ub: reading capacity: error %d\n", cmd->error); /* P3 */
1893                 rc = -EIO;
1894                 goto err_read;
1895         }
1896         if (cmd->act_len != 8) {
1897                 printk("ub: reading capacity: size %d\n", cmd->act_len); /* P3 */
1898                 rc = -EIO;
1899                 goto err_read;
1900         }
1901
1902         /* sd.c special-cases sector size of 0 to mean 512. Needed? Safe? */
1903         nsec = be32_to_cpu(*(__be32 *)p) + 1;
1904         bsize = be32_to_cpu(*(__be32 *)(p + 4));
1905         switch (bsize) {
1906         case 512:       shift = 0;      break;
1907         case 1024:      shift = 1;      break;
1908         case 2048:      shift = 2;      break;
1909         case 4096:      shift = 3;      break;
1910         default:
1911                 printk("ub: Bad sector size %u\n", bsize); /* P3 */
1912                 rc = -EDOM;
1913                 goto err_inv_bsize;
1914         }
1915
1916         ret->bsize = bsize;
1917         ret->bshift = shift;
1918         ret->nsec = nsec << shift;
1919         rc = 0;
1920
1921 err_inv_bsize:
1922 err_read:
1923 err_submit:
1924         kfree(cmd);
1925 err_alloc:
1926         return rc;
1927 }
1928
1929 /*
1930  */
1931 static void ub_probe_urb_complete(struct urb *urb, struct pt_regs *pt)
1932 {
1933         struct completion *cop = urb->context;
1934         complete(cop);
1935 }
1936
1937 static void ub_probe_timeout(unsigned long arg)
1938 {
1939         struct completion *cop = (struct completion *) arg;
1940         complete(cop);
1941 }
1942
1943 /*
1944  * Reset with a Bulk reset.
1945  */
1946 static int ub_sync_reset(struct ub_dev *sc)
1947 {
1948         int ifnum = sc->intf->cur_altsetting->desc.bInterfaceNumber;
1949         struct usb_ctrlrequest *cr;
1950         struct completion compl;
1951         struct timer_list timer;
1952         int rc;
1953
1954         init_completion(&compl);
1955
1956         cr = &sc->work_cr;
1957         cr->bRequestType = USB_TYPE_CLASS | USB_RECIP_INTERFACE;
1958         cr->bRequest = US_BULK_RESET_REQUEST;
1959         cr->wValue = cpu_to_le16(0);
1960         cr->wIndex = cpu_to_le16(ifnum);
1961         cr->wLength = cpu_to_le16(0);
1962
1963         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->send_ctrl_pipe,
1964             (unsigned char*) cr, NULL, 0, ub_probe_urb_complete, &compl);
1965         sc->work_urb.actual_length = 0;
1966         sc->work_urb.error_count = 0;
1967         sc->work_urb.status = 0;
1968
1969         if ((rc = usb_submit_urb(&sc->work_urb, GFP_KERNEL)) != 0) {
1970                 printk(KERN_WARNING
1971                      "%s: Unable to submit a bulk reset (%d)\n", sc->name, rc);
1972                 return rc;
1973         }
1974
1975         init_timer(&timer);
1976         timer.function = ub_probe_timeout;
1977         timer.data = (unsigned long) &compl;
1978         timer.expires = jiffies + UB_CTRL_TIMEOUT;
1979         add_timer(&timer);
1980
1981         wait_for_completion(&compl);
1982
1983         del_timer_sync(&timer);
1984         usb_kill_urb(&sc->work_urb);
1985
1986         return sc->work_urb.status;
1987 }
1988
1989 /*
1990  * Get number of LUNs by the way of Bulk GetMaxLUN command.
1991  */
1992 static int ub_sync_getmaxlun(struct ub_dev *sc)
1993 {
1994         int ifnum = sc->intf->cur_altsetting->desc.bInterfaceNumber;
1995         unsigned char *p;
1996         enum { ALLOC_SIZE = 1 };
1997         struct usb_ctrlrequest *cr;
1998         struct completion compl;
1999         struct timer_list timer;
2000         int nluns;
2001         int rc;
2002
2003         init_completion(&compl);
2004
2005         rc = -ENOMEM;
2006         if ((p = kmalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
2007                 goto err_alloc;
2008         *p = 55;
2009
2010         cr = &sc->work_cr;
2011         cr->bRequestType = USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE;
2012         cr->bRequest = US_BULK_GET_MAX_LUN;
2013         cr->wValue = cpu_to_le16(0);
2014         cr->wIndex = cpu_to_le16(ifnum);
2015         cr->wLength = cpu_to_le16(1);
2016
2017         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->recv_ctrl_pipe,
2018             (unsigned char*) cr, p, 1, ub_probe_urb_complete, &compl);
2019         sc->work_urb.actual_length = 0;
2020         sc->work_urb.error_count = 0;
2021         sc->work_urb.status = 0;
2022
2023         if ((rc = usb_submit_urb(&sc->work_urb, GFP_KERNEL)) != 0) {
2024                 if (rc == -EPIPE) {
2025                         printk("%s: Stall submitting GetMaxLUN, using 1 LUN\n",
2026                              sc->name); /* P3 */
2027                 } else {
2028                         printk(KERN_NOTICE
2029                              "%s: Unable to submit GetMaxLUN (%d)\n",
2030                              sc->name, rc);
2031                 }
2032                 goto err_submit;
2033         }
2034
2035         init_timer(&timer);
2036         timer.function = ub_probe_timeout;
2037         timer.data = (unsigned long) &compl;
2038         timer.expires = jiffies + UB_CTRL_TIMEOUT;
2039         add_timer(&timer);
2040
2041         wait_for_completion(&compl);
2042
2043         del_timer_sync(&timer);
2044         usb_kill_urb(&sc->work_urb);
2045
2046         if ((rc = sc->work_urb.status) < 0) {
2047                 if (rc == -EPIPE) {
2048                         printk("%s: Stall at GetMaxLUN, using 1 LUN\n",
2049                              sc->name); /* P3 */
2050                 } else {
2051                         printk(KERN_NOTICE
2052                              "%s: Error at GetMaxLUN (%d)\n",
2053                              sc->name, rc);
2054                 }
2055                 goto err_io;
2056         }
2057
2058         if (sc->work_urb.actual_length != 1) {
2059                 printk("%s: GetMaxLUN returned %d bytes\n", sc->name,
2060                     sc->work_urb.actual_length); /* P3 */
2061                 nluns = 0;
2062         } else {
2063                 if ((nluns = *p) == 55) {
2064                         nluns = 0;
2065                 } else {
2066                         /* GetMaxLUN returns the maximum LUN number */
2067                         nluns += 1;
2068                         if (nluns > UB_MAX_LUNS)
2069                                 nluns = UB_MAX_LUNS;
2070                 }
2071                 printk("%s: GetMaxLUN returned %d, using %d LUNs\n", sc->name,
2072                     *p, nluns); /* P3 */
2073         }
2074
2075         kfree(p);
2076         return nluns;
2077
2078 err_io:
2079 err_submit:
2080         kfree(p);
2081 err_alloc:
2082         return rc;
2083 }
2084
2085 /*
2086  * Clear initial stalls.
2087  */
2088 static int ub_probe_clear_stall(struct ub_dev *sc, int stalled_pipe)
2089 {
2090         int endp;
2091         struct usb_ctrlrequest *cr;
2092         struct completion compl;
2093         struct timer_list timer;
2094         int rc;
2095
2096         init_completion(&compl);
2097
2098         endp = usb_pipeendpoint(stalled_pipe);
2099         if (usb_pipein (stalled_pipe))
2100                 endp |= USB_DIR_IN;
2101
2102         cr = &sc->work_cr;
2103         cr->bRequestType = USB_RECIP_ENDPOINT;
2104         cr->bRequest = USB_REQ_CLEAR_FEATURE;
2105         cr->wValue = cpu_to_le16(USB_ENDPOINT_HALT);
2106         cr->wIndex = cpu_to_le16(endp);
2107         cr->wLength = cpu_to_le16(0);
2108
2109         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->send_ctrl_pipe,
2110             (unsigned char*) cr, NULL, 0, ub_probe_urb_complete, &compl);
2111         sc->work_urb.actual_length = 0;
2112         sc->work_urb.error_count = 0;
2113         sc->work_urb.status = 0;
2114
2115         if ((rc = usb_submit_urb(&sc->work_urb, GFP_KERNEL)) != 0) {
2116                 printk(KERN_WARNING
2117                      "%s: Unable to submit a probe clear (%d)\n", sc->name, rc);
2118                 return rc;
2119         }
2120
2121         init_timer(&timer);
2122         timer.function = ub_probe_timeout;
2123         timer.data = (unsigned long) &compl;
2124         timer.expires = jiffies + UB_CTRL_TIMEOUT;
2125         add_timer(&timer);
2126
2127         wait_for_completion(&compl);
2128
2129         del_timer_sync(&timer);
2130         usb_kill_urb(&sc->work_urb);
2131
2132         /* reset the endpoint toggle */
2133         usb_settoggle(sc->dev, endp, usb_pipeout(sc->last_pipe), 0);
2134
2135         return 0;
2136 }
2137
2138 /*
2139  * Get the pipe settings.
2140  */
2141 static int ub_get_pipes(struct ub_dev *sc, struct usb_device *dev,
2142     struct usb_interface *intf)
2143 {
2144         struct usb_host_interface *altsetting = intf->cur_altsetting;
2145         struct usb_endpoint_descriptor *ep_in = NULL;
2146         struct usb_endpoint_descriptor *ep_out = NULL;
2147         struct usb_endpoint_descriptor *ep;
2148         int i;
2149
2150         /*
2151          * Find the endpoints we need.
2152          * We are expecting a minimum of 2 endpoints - in and out (bulk).
2153          * We will ignore any others.
2154          */
2155         for (i = 0; i < altsetting->desc.bNumEndpoints; i++) {
2156                 ep = &altsetting->endpoint[i].desc;
2157
2158                 /* Is it a BULK endpoint? */
2159                 if ((ep->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK)
2160                                 == USB_ENDPOINT_XFER_BULK) {
2161                         /* BULK in or out? */
2162                         if (ep->bEndpointAddress & USB_DIR_IN)
2163                                 ep_in = ep;
2164                         else
2165                                 ep_out = ep;
2166                 }
2167         }
2168
2169         if (ep_in == NULL || ep_out == NULL) {
2170                 printk(KERN_NOTICE "%s: failed endpoint check\n",
2171                     sc->name);
2172                 return -ENODEV;
2173         }
2174
2175         /* Calculate and store the pipe values */
2176         sc->send_ctrl_pipe = usb_sndctrlpipe(dev, 0);
2177         sc->recv_ctrl_pipe = usb_rcvctrlpipe(dev, 0);
2178         sc->send_bulk_pipe = usb_sndbulkpipe(dev,
2179                 ep_out->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2180         sc->recv_bulk_pipe = usb_rcvbulkpipe(dev,
2181                 ep_in->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2182
2183         return 0;
2184 }
2185
2186 /*
2187  * Probing is done in the process context, which allows us to cheat
2188  * and not to build a state machine for the discovery.
2189  */
2190 static int ub_probe(struct usb_interface *intf,
2191     const struct usb_device_id *dev_id)
2192 {
2193         struct ub_dev *sc;
2194         int nluns;
2195         int rc;
2196         int i;
2197
2198         if (usb_usual_check_type(dev_id, USB_US_TYPE_UB))
2199                 return -ENXIO;
2200
2201         rc = -ENOMEM;
2202         if ((sc = kzalloc(sizeof(struct ub_dev), GFP_KERNEL)) == NULL)
2203                 goto err_core;
2204         sc->lock = ub_next_lock();
2205         INIT_LIST_HEAD(&sc->luns);
2206         usb_init_urb(&sc->work_urb);
2207         tasklet_init(&sc->tasklet, ub_scsi_action, (unsigned long)sc);
2208         atomic_set(&sc->poison, 0);
2209         INIT_WORK(&sc->reset_work, ub_reset_task, sc);
2210         init_waitqueue_head(&sc->reset_wait);
2211
2212         init_timer(&sc->work_timer);
2213         sc->work_timer.data = (unsigned long) sc;
2214         sc->work_timer.function = ub_urb_timeout;
2215
2216         ub_init_completion(&sc->work_done);
2217         sc->work_done.done = 1;         /* A little yuk, but oh well... */
2218
2219         sc->dev = interface_to_usbdev(intf);
2220         sc->intf = intf;
2221         // sc->ifnum = intf->cur_altsetting->desc.bInterfaceNumber;
2222         usb_set_intfdata(intf, sc);
2223         usb_get_dev(sc->dev);
2224         // usb_get_intf(sc->intf);      /* Do we need this? */
2225
2226         snprintf(sc->name, 12, DRV_NAME "(%d.%d)",
2227             sc->dev->bus->busnum, sc->dev->devnum);
2228
2229         /* XXX Verify that we can handle the device (from descriptors) */
2230
2231         if (ub_get_pipes(sc, sc->dev, intf) != 0)
2232                 goto err_dev_desc;
2233
2234         /*
2235          * At this point, all USB initialization is done, do upper layer.
2236          * We really hate halfway initialized structures, so from the
2237          * invariants perspective, this ub_dev is fully constructed at
2238          * this point.
2239          */
2240
2241         /*
2242          * This is needed to clear toggles. It is a problem only if we do
2243          * `rmmod ub && modprobe ub` without disconnects, but we like that.
2244          */
2245 #if 0 /* iPod Mini fails if we do this (big white iPod works) */
2246         ub_probe_clear_stall(sc, sc->recv_bulk_pipe);
2247         ub_probe_clear_stall(sc, sc->send_bulk_pipe);
2248 #endif
2249
2250         /*
2251          * The way this is used by the startup code is a little specific.
2252          * A SCSI check causes a USB stall. Our common case code sees it
2253          * and clears the check, after which the device is ready for use.
2254          * But if a check was not present, any command other than
2255          * TEST_UNIT_READY ends with a lockup (including REQUEST_SENSE).
2256          *
2257          * If we neglect to clear the SCSI check, the first real command fails
2258          * (which is the capacity readout). We clear that and retry, but why
2259          * causing spurious retries for no reason.
2260          *
2261          * Revalidation may start with its own TEST_UNIT_READY, but that one
2262          * has to succeed, so we clear checks with an additional one here.
2263          * In any case it's not our business how revaliadation is implemented.
2264          */
2265         for (i = 0; i < 3; i++) {       /* Retries for benh's key */
2266                 if ((rc = ub_sync_tur(sc, NULL)) <= 0) break;
2267                 if (rc != 0x6) break;
2268                 msleep(10);
2269         }
2270
2271         nluns = 1;
2272         for (i = 0; i < 3; i++) {
2273                 if ((rc = ub_sync_getmaxlun(sc)) < 0)
2274                         break;
2275                 if (rc != 0) {
2276                         nluns = rc;
2277                         break;
2278                 }
2279                 msleep(100);
2280         }
2281
2282         for (i = 0; i < nluns; i++) {
2283                 ub_probe_lun(sc, i);
2284         }
2285         return 0;
2286
2287 err_dev_desc:
2288         usb_set_intfdata(intf, NULL);
2289         // usb_put_intf(sc->intf);
2290         usb_put_dev(sc->dev);
2291         kfree(sc);
2292 err_core:
2293         return rc;
2294 }
2295
2296 static int ub_probe_lun(struct ub_dev *sc, int lnum)
2297 {
2298         struct ub_lun *lun;
2299         request_queue_t *q;
2300         struct gendisk *disk;
2301         int rc;
2302
2303         rc = -ENOMEM;
2304         if ((lun = kzalloc(sizeof(struct ub_lun), GFP_KERNEL)) == NULL)
2305                 goto err_alloc;
2306         lun->num = lnum;
2307
2308         rc = -ENOSR;
2309         if ((lun->id = ub_id_get()) == -1)
2310                 goto err_id;
2311
2312         lun->udev = sc;
2313         list_add(&lun->link, &sc->luns);
2314
2315         snprintf(lun->name, 16, DRV_NAME "%c(%d.%d.%d)",
2316             lun->id + 'a', sc->dev->bus->busnum, sc->dev->devnum, lun->num);
2317
2318         lun->removable = 1;             /* XXX Query this from the device */
2319         lun->changed = 1;               /* ub_revalidate clears only */
2320         ub_revalidate(sc, lun);
2321
2322         rc = -ENOMEM;
2323         if ((disk = alloc_disk(UB_PARTS_PER_LUN)) == NULL)
2324                 goto err_diskalloc;
2325
2326         lun->disk = disk;
2327         sprintf(disk->disk_name, DRV_NAME "%c", lun->id + 'a');
2328         sprintf(disk->devfs_name, DEVFS_NAME "/%c", lun->id + 'a');
2329         disk->major = UB_MAJOR;
2330         disk->first_minor = lun->id * UB_PARTS_PER_LUN;
2331         disk->fops = &ub_bd_fops;
2332         disk->private_data = lun;
2333         disk->driverfs_dev = &sc->intf->dev;
2334
2335         rc = -ENOMEM;
2336         if ((q = blk_init_queue(ub_request_fn, sc->lock)) == NULL)
2337                 goto err_blkqinit;
2338
2339         disk->queue = q;
2340
2341         blk_queue_bounce_limit(q, BLK_BOUNCE_HIGH);
2342         blk_queue_max_hw_segments(q, UB_MAX_REQ_SG);
2343         blk_queue_max_phys_segments(q, UB_MAX_REQ_SG);
2344         blk_queue_segment_boundary(q, 0xffffffff);      /* Dubious. */
2345         blk_queue_max_sectors(q, UB_MAX_SECTORS);
2346         blk_queue_hardsect_size(q, lun->capacity.bsize);
2347
2348         q->queuedata = lun;
2349
2350         set_capacity(disk, lun->capacity.nsec);
2351         if (lun->removable)
2352                 disk->flags |= GENHD_FL_REMOVABLE;
2353
2354         add_disk(disk);
2355
2356         return 0;
2357
2358 err_blkqinit:
2359         put_disk(disk);
2360 err_diskalloc:
2361         list_del(&lun->link);
2362         ub_id_put(lun->id);
2363 err_id:
2364         kfree(lun);
2365 err_alloc:
2366         return rc;
2367 }
2368
2369 static void ub_disconnect(struct usb_interface *intf)
2370 {
2371         struct ub_dev *sc = usb_get_intfdata(intf);
2372         struct list_head *p;
2373         struct ub_lun *lun;
2374         struct gendisk *disk;
2375         unsigned long flags;
2376
2377         /*
2378          * Prevent ub_bd_release from pulling the rug from under us.
2379          * XXX This is starting to look like a kref.
2380          * XXX Why not to take this ref at probe time?
2381          */
2382         spin_lock_irqsave(&ub_lock, flags);
2383         sc->openc++;
2384         spin_unlock_irqrestore(&ub_lock, flags);
2385
2386         /*
2387          * Fence stall clearnings, operations triggered by unlinkings and so on.
2388          * We do not attempt to unlink any URBs, because we do not trust the
2389          * unlink paths in HC drivers. Also, we get -84 upon disconnect anyway.
2390          */
2391         atomic_set(&sc->poison, 1);
2392
2393         /*
2394          * Wait for reset to end, if any.
2395          */
2396         wait_event(sc->reset_wait, !sc->reset);
2397
2398         /*
2399          * Blow away queued commands.
2400          *
2401          * Actually, this never works, because before we get here
2402          * the HCD terminates outstanding URB(s). It causes our
2403          * SCSI command queue to advance, commands fail to submit,
2404          * and the whole queue drains. So, we just use this code to
2405          * print warnings.
2406          */
2407         spin_lock_irqsave(sc->lock, flags);
2408         {
2409                 struct ub_scsi_cmd *cmd;
2410                 int cnt = 0;
2411                 while ((cmd = ub_cmdq_peek(sc)) != NULL) {
2412                         cmd->error = -ENOTCONN;
2413                         cmd->state = UB_CMDST_DONE;
2414                         ub_cmdq_pop(sc);
2415                         (*cmd->done)(sc, cmd);
2416                         cnt++;
2417                 }
2418                 if (cnt != 0) {
2419                         printk(KERN_WARNING "%s: "
2420                             "%d was queued after shutdown\n", sc->name, cnt);
2421                 }
2422         }
2423         spin_unlock_irqrestore(sc->lock, flags);
2424
2425         /*
2426          * Unregister the upper layer.
2427          */
2428         list_for_each (p, &sc->luns) {
2429                 lun = list_entry(p, struct ub_lun, link);
2430                 disk = lun->disk;
2431                 if (disk->flags & GENHD_FL_UP)
2432                         del_gendisk(disk);
2433                 /*
2434                  * I wish I could do:
2435                  *    set_bit(QUEUE_FLAG_DEAD, &q->queue_flags);
2436                  * As it is, we rely on our internal poisoning and let
2437                  * the upper levels to spin furiously failing all the I/O.
2438                  */
2439         }
2440
2441         /*
2442          * Testing for -EINPROGRESS is always a bug, so we are bending
2443          * the rules a little.
2444          */
2445         spin_lock_irqsave(sc->lock, flags);
2446         if (sc->work_urb.status == -EINPROGRESS) {      /* janitors: ignore */
2447                 printk(KERN_WARNING "%s: "
2448                     "URB is active after disconnect\n", sc->name);
2449         }
2450         spin_unlock_irqrestore(sc->lock, flags);
2451
2452         /*
2453          * There is virtually no chance that other CPU runs times so long
2454          * after ub_urb_complete should have called del_timer, but only if HCD
2455          * didn't forget to deliver a callback on unlink.
2456          */
2457         del_timer_sync(&sc->work_timer);
2458
2459         /*
2460          * At this point there must be no commands coming from anyone
2461          * and no URBs left in transit.
2462          */
2463
2464         usb_set_intfdata(intf, NULL);
2465         // usb_put_intf(sc->intf);
2466         sc->intf = NULL;
2467         usb_put_dev(sc->dev);
2468         sc->dev = NULL;
2469
2470         ub_put(sc);
2471 }
2472
2473 static struct usb_driver ub_driver = {
2474         .name =         "ub",
2475         .probe =        ub_probe,
2476         .disconnect =   ub_disconnect,
2477         .id_table =     ub_usb_ids,
2478 };
2479
2480 static int __init ub_init(void)
2481 {
2482         int rc;
2483         int i;
2484
2485         for (i = 0; i < UB_QLOCK_NUM; i++)
2486                 spin_lock_init(&ub_qlockv[i]);
2487
2488         if ((rc = register_blkdev(UB_MAJOR, DRV_NAME)) != 0)
2489                 goto err_regblkdev;
2490         devfs_mk_dir(DEVFS_NAME);
2491
2492         if ((rc = usb_register(&ub_driver)) != 0)
2493                 goto err_register;
2494
2495         usb_usual_set_present(USB_US_TYPE_UB);
2496         return 0;
2497
2498 err_register:
2499         devfs_remove(DEVFS_NAME);
2500         unregister_blkdev(UB_MAJOR, DRV_NAME);
2501 err_regblkdev:
2502         return rc;
2503 }
2504
2505 static void __exit ub_exit(void)
2506 {
2507         usb_deregister(&ub_driver);
2508
2509         devfs_remove(DEVFS_NAME);
2510         unregister_blkdev(UB_MAJOR, DRV_NAME);
2511         usb_usual_clear_present(USB_US_TYPE_UB);
2512 }
2513
2514 module_init(ub_init);
2515 module_exit(ub_exit);
2516
2517 MODULE_LICENSE("GPL");