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  *  -- Return sense now that rq allows it (we always auto-sense anyway).
  12  *  -- set readonly flag for CDs, set removable flag for CF readers
  13  *  -- do inquiry and verify we got a disk and not a tape (for LUN mismatch)
  14  *  -- verify the 13 conditions and do bulk resets
  15  *  -- highmem
  16  *  -- move top_sense and work_bcs into separate allocations (if they survive)
  17  *     for cache purists and esoteric architectures.
  18  *  -- Allocate structure for LUN 0 before the first ub_sync_tur, avoid NULL. ?
  19  *  -- prune comments, they are too volumnous
  20  *  -- Resove XXX's
  21  *  -- CLEAR, CLR2STS, CLRRS seem to be ripe for refactoring.
  22  */
  23 #include <linux/kernel.h>
  24 #include <linux/module.h>
  25 #include <linux/usb.h>
  26 #include <linux/usb_usual.h>
  27 #include <linux/blkdev.h>
  28 #include <linux/timer.h>
  29 #include <linux/scatterlist.h>
  30 #include <linux/slab.h>
  31 #include <linux/smp_lock.h>
  32 #include <scsi/scsi.h>
  33
  34 #define DRV_NAME "ub"
  35
  36 #define UB_MAJOR 180
  37
  38 /*
  39  * The command state machine is the key model for understanding of this driver.
  40  *
  41  * The general rule is that all transitions are done towards the bottom
  42  * of the diagram, thus preventing any loops.
  43  *
  44  * An exception to that is how the STAT state is handled. A counter allows it
  45  * to be re-entered along the path marked with [C].
  46  *
  47  *       +--------+
  48  *       ! INIT   !
  49  *       +--------+
  50  *           !
  51  *        ub_scsi_cmd_start fails ->--------------------------------------\
  52  *           !                                                            !
  53  *           V                                                            !
  54  *       +--------+                                                       !
  55  *       ! CMD    !                                                       !
  56  *       +--------+                                                       !
  57  *           !                                            +--------+      !
  58  *         was -EPIPE -->-------------------------------->! CLEAR  !      !
  59  *           !                                            +--------+      !
  60  *           !                                                !           !
  61  *         was error -->------------------------------------- ! --------->\
  62  *           !                                                !           !
  63  *  /--<-- cmd->dir == NONE ?                                 !           !
  64  *  !        !                                                !           !
  65  *  !        V                                                !           !
  66  *  !    +--------+                                           !           !
  67  *  !    ! DATA   !                                           !           !
  68  *  !    +--------+                                           !           !
  69  *  !        !                           +---------+          !           !
  70  *  !      was -EPIPE -->--------------->! CLR2STS !          !           !
  71  *  !        !                           +---------+          !           !
  72  *  !        !                                !               !           !
  73  *  !        !                              was error -->---- ! --------->\
  74  *  !      was error -->--------------------- ! ------------- ! --------->\
  75  *  !        !                                !               !           !
  76  *  !        V                                !               !           !
  77  *  \--->+--------+                           !               !           !
  78  *       ! STAT   !<--------------------------/               !           !
  79  *  /--->+--------+                                           !           !
  80  *  !        !                                                !           !
  81  * [C]     was -EPIPE -->-----------\                         !           !
  82  *  !        !                      !                         !           !
  83  *  +<---- len == 0                 !                         !           !
  84  *  !        !                      !                         !           !
  85  *  !      was error -->--------------------------------------!---------->\
  86  *  !        !                      !                         !           !
  87  *  +<---- bad CSW                  !                         !           !
  88  *  +<---- bad tag                  !                         !           !
  89  *  !        !                      V                         !           !
  90  *  !        !                 +--------+                     !           !
  91  *  !        !                 ! CLRRS  !                     !           !
  92  *  !        !                 +--------+                     !           !
  93  *  !        !                      !                         !           !
  94  *  \------- ! --------------------[C]--------\               !           !
  95  *           !                                !               !           !
  96  *         cmd->error---\                +--------+           !           !
  97  *           !          +--------------->! SENSE  !<----------/           !
  98  *         STAT_FAIL----/                +--------+                       !
  99  *           !                                !                           V
 100  *           !                                V                      +--------+
 101  *           \--------------------------------\--------------------->! DONE   !
 102  *                                                                   +--------+
 103  */
 104
 105 /*
 106  * This many LUNs per USB device.
 107  * Every one of them takes a host, see UB_MAX_HOSTS.
 108  */
 109 #define UB_MAX_LUNS   9
 110
 111 /*
 112  */
 113
 114 #define UB_PARTS_PER_LUN      8
 115
 116 #define UB_MAX_CDB_SIZE      16         /* Corresponds to Bulk */
 117
 118 #define UB_SENSE_SIZE  18
 119
 120 /*
 121  */
 122
 123 /* command block wrapper */
 124 struct bulk_cb_wrap {
 125         __le32  Signature;              /* contains 'USBC' */
 126         u32     Tag;                    /* unique per command id */
 127         __le32  DataTransferLength;     /* size of data */
 128         u8      Flags;                  /* direction in bit 0 */
 129         u8      Lun;                    /* LUN */
 130         u8      Length;                 /* of of the CDB */
 131         u8      CDB[UB_MAX_CDB_SIZE];   /* max command */
 132 };
 133
 134 #define US_BULK_CB_WRAP_LEN     31
 135 #define US_BULK_CB_SIGN         0x43425355      /*spells out USBC */
 136 #define US_BULK_FLAG_IN         1
 137 #define US_BULK_FLAG_OUT        0
 138
 139 /* command status wrapper */
 140 struct bulk_cs_wrap {
 141         __le32  Signature;              /* should = 'USBS' */
 142         u32     Tag;                    /* same as original command */
 143         __le32  Residue;                /* amount not transferred */
 144         u8      Status;                 /* see below */
 145 };
 146
 147 #define US_BULK_CS_WRAP_LEN     13
 148 #define US_BULK_CS_SIGN         0x53425355      /* spells out 'USBS' */
 149 #define US_BULK_STAT_OK         0
 150 #define US_BULK_STAT_FAIL       1
 151 #define US_BULK_STAT_PHASE      2
 152
 153 /* bulk-only class specific requests */
 154 #define US_BULK_RESET_REQUEST   0xff
 155 #define US_BULK_GET_MAX_LUN     0xfe
 156
 157 /*
 158  */
 159 struct ub_dev;
 160
 161 #define UB_MAX_REQ_SG   9       /* cdrecord requires 32KB and maybe a header */
 162 #define UB_MAX_SECTORS 64
 163
 164 /*
 165  * A second is more than enough for a 32K transfer (UB_MAX_SECTORS)
 166  * even if a webcam hogs the bus, but some devices need time to spin up.
 167  */
 168 #define UB_URB_TIMEOUT  (HZ*2)
 169 #define UB_DATA_TIMEOUT (HZ*5)  /* ZIP does spin-ups in the data phase */
 170 #define UB_STAT_TIMEOUT (HZ*5)  /* Same spinups and eject for a dataless cmd. */
 171 #define UB_CTRL_TIMEOUT (HZ/2)  /* 500ms ought to be enough to clear a stall */
 172
 173 /*
 174  * An instance of a SCSI command in transit.
 175  */
 176 #define UB_DIR_NONE     0
 177 #define UB_DIR_READ     1
 178 #define UB_DIR_ILLEGAL2 2
 179 #define UB_DIR_WRITE    3
 180
 181 #define UB_DIR_CHAR(c)  (((c)==UB_DIR_WRITE)? 'w': \
 182                          (((c)==UB_DIR_READ)? 'r': 'n'))
 183
 184 enum ub_scsi_cmd_state {
 185         UB_CMDST_INIT,                  /* Initial state */
 186         UB_CMDST_CMD,                   /* Command submitted */
 187         UB_CMDST_DATA,                  /* Data phase */
 188         UB_CMDST_CLR2STS,               /* Clearing before requesting status */
 189         UB_CMDST_STAT,                  /* Status phase */
 190         UB_CMDST_CLEAR,                 /* Clearing a stall (halt, actually) */
 191         UB_CMDST_CLRRS,                 /* Clearing before retrying status */
 192         UB_CMDST_SENSE,                 /* Sending Request Sense */
 193         UB_CMDST_DONE                   /* Final state */
 194 };
 195
 196 struct ub_scsi_cmd {
 197         unsigned char cdb[UB_MAX_CDB_SIZE];
 198         unsigned char cdb_len;
 199
 200         unsigned char dir;              /* 0 - none, 1 - read, 3 - write. */
 201         enum ub_scsi_cmd_state state;
 202         unsigned int tag;
 203         struct ub_scsi_cmd *next;
 204
 205         int error;                      /* Return code - valid upon done */
 206         unsigned int act_len;           /* Return size */
 207         unsigned char key, asc, ascq;   /* May be valid if error==-EIO */
 208
 209         int stat_count;                 /* Retries getting status. */
 210         unsigned int timeo;             /* jiffies until rq->timeout changes */
 211
 212         unsigned int len;               /* Requested length */
 213         unsigned int current_sg;
 214         unsigned int nsg;               /* sgv[nsg] */
 215         struct scatterlist sgv[UB_MAX_REQ_SG];
 216
 217         struct ub_lun *lun;
 218         void (*done)(struct ub_dev *, struct ub_scsi_cmd *);
 219         void *back;
 220 };
 221
 222 struct ub_request {
 223         struct request *rq;
 224         unsigned int current_try;
 225         unsigned int nsg;               /* sgv[nsg] */
 226         struct scatterlist sgv[UB_MAX_REQ_SG];
 227 };
 228
 229 /*
 230  */
 231 struct ub_capacity {
 232         unsigned long nsec;             /* Linux size - 512 byte sectors */
 233         unsigned int bsize;             /* Linux hardsect_size */
 234         unsigned int bshift;            /* Shift between 512 and hard sects */
 235 };
 236
 237 /*
 238  * This is a direct take-off from linux/include/completion.h
 239  * The difference is that I do not wait on this thing, just poll.
 240  * When I want to wait (ub_probe), I just use the stock completion.
 241  *
 242  * Note that INIT_COMPLETION takes no lock. It is correct. But why
 243  * in the bloody hell that thing takes struct instead of pointer to struct
 244  * is quite beyond me. I just copied it from the stock completion.
 245  */
 246 struct ub_completion {
 247         unsigned int done;
 248         spinlock_t lock;
 249 };
 250
 251 static inline void ub_init_completion(struct ub_completion *x)
 252 {
 253         x->done = 0;
 254         spin_lock_init(&x->lock);
 255 }
 256
 257 #define UB_INIT_COMPLETION(x)   ((x).done = 0)
 258
 259 static void ub_complete(struct ub_completion *x)
 260 {
 261         unsigned long flags;
 262
 263         spin_lock_irqsave(&x->lock, flags);
 264         x->done++;
 265         spin_unlock_irqrestore(&x->lock, flags);
 266 }
 267
 268 static int ub_is_completed(struct ub_completion *x)
 269 {
 270         unsigned long flags;
 271         int ret;
 272
 273         spin_lock_irqsave(&x->lock, flags);
 274         ret = x->done;
 275         spin_unlock_irqrestore(&x->lock, flags);
 276         return ret;
 277 }
 278
 279 /*
 280  */
 281 struct ub_scsi_cmd_queue {
 282         int qlen, qmax;
 283         struct ub_scsi_cmd *head, *tail;
 284 };
 285
 286 /*
 287  * The block device instance (one per LUN).
 288  */
 289 struct ub_lun {
 290         struct ub_dev *udev;
 291         struct list_head link;
 292         struct gendisk *disk;
 293         int id;                         /* Host index */
 294         int num;                        /* LUN number */
 295         char name[16];
 296
 297         int changed;                    /* Media was changed */
 298         int removable;
 299         int readonly;
 300
 301         struct ub_request urq;
 302
 303         /* Use Ingo's mempool if or when we have more than one command. */
 304         /*
 305          * Currently we never need more than one command for the whole device.
 306          * However, giving every LUN a command is a cheap and automatic way
 307          * to enforce fairness between them.
 308          */
 309         int cmda[1];
 310         struct ub_scsi_cmd cmdv[1];
 311
 312         struct ub_capacity capacity;
 313 };
 314
 315 /*
 316  * The USB device instance.
 317  */
 318 struct ub_dev {
 319         spinlock_t *lock;
 320         atomic_t poison;                /* The USB device is disconnected */
 321         int openc;                      /* protected by ub_lock! */
 322                                         /* kref is too implicit for our taste */
 323         int reset;                      /* Reset is running */
 324         int bad_resid;
 325         unsigned int tagcnt;
 326         char name[12];
 327         struct usb_device *dev;
 328         struct usb_interface *intf;
 329
 330         struct list_head luns;
 331
 332         unsigned int send_bulk_pipe;    /* cached pipe values */
 333         unsigned int recv_bulk_pipe;
 334         unsigned int send_ctrl_pipe;
 335         unsigned int recv_ctrl_pipe;
 336
 337         struct tasklet_struct tasklet;
 338
 339         struct ub_scsi_cmd_queue cmd_queue;
 340         struct ub_scsi_cmd top_rqs_cmd; /* REQUEST SENSE */
 341         unsigned char top_sense[UB_SENSE_SIZE];
 342
 343         struct ub_completion work_done;
 344         struct urb work_urb;
 345         struct timer_list work_timer;
 346         int last_pipe;                  /* What might need clearing */
 347         __le32 signature;               /* Learned signature */
 348         struct bulk_cb_wrap work_bcb;
 349         struct bulk_cs_wrap work_bcs;
 350         struct usb_ctrlrequest work_cr;
 351
 352         struct work_struct reset_work;
 353         wait_queue_head_t reset_wait;
 354 };
 355
 356 /*
 357  */
 358 static void ub_cleanup(struct ub_dev *sc);
 359 static int ub_request_fn_1(struct ub_lun *lun, struct request *rq);
 360 static void ub_cmd_build_block(struct ub_dev *sc, struct ub_lun *lun,
 361     struct ub_scsi_cmd *cmd, struct ub_request *urq);
 362 static void ub_cmd_build_packet(struct ub_dev *sc, struct ub_lun *lun,
 363     struct ub_scsi_cmd *cmd, struct ub_request *urq);
 364 static void ub_rw_cmd_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 365 static void ub_end_rq(struct request *rq, unsigned int status);
 366 static int ub_rw_cmd_retry(struct ub_dev *sc, struct ub_lun *lun,
 367     struct ub_request *urq, struct ub_scsi_cmd *cmd);
 368 static int ub_submit_scsi(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 369 static void ub_urb_complete(struct urb *urb);
 370 static void ub_scsi_action(unsigned long _dev);
 371 static void ub_scsi_dispatch(struct ub_dev *sc);
 372 static void ub_scsi_urb_compl(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 373 static void ub_data_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 374 static void ub_state_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd, int rc);
 375 static int __ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 376 static void ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 377 static void ub_state_stat_counted(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 378 static void ub_state_sense(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 379 static int ub_submit_clear_stall(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
 380     int stalled_pipe);
 381 static void ub_top_sense_done(struct ub_dev *sc, struct ub_scsi_cmd *scmd);
 382 static void ub_reset_enter(struct ub_dev *sc, int try);
 383 static void ub_reset_task(struct work_struct *work);
 384 static int ub_sync_tur(struct ub_dev *sc, struct ub_lun *lun);
 385 static int ub_sync_read_cap(struct ub_dev *sc, struct ub_lun *lun,
 386     struct ub_capacity *ret);
 387 static int ub_sync_reset(struct ub_dev *sc);
 388 static int ub_probe_clear_stall(struct ub_dev *sc, int stalled_pipe);
 389 static int ub_probe_lun(struct ub_dev *sc, int lnum);
 390
 391 /*
 392  */
 393 #ifdef CONFIG_USB_LIBUSUAL
 394
 395 #define ub_usb_ids  usb_storage_usb_ids
 396 #else
 397
 398 static const struct usb_device_id ub_usb_ids[] = {
 399         { USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, US_SC_SCSI, US_PR_BULK) },
 400         { }
 401 };
 402
 403 MODULE_DEVICE_TABLE(usb, ub_usb_ids);
 404 #endif /* CONFIG_USB_LIBUSUAL */
 405
 406 /*
 407  * Find me a way to identify "next free minor" for add_disk(),
 408  * and the array disappears the next day. However, the number of
 409  * hosts has something to do with the naming and /proc/partitions.
 410  * This has to be thought out in detail before changing.
 411  * If UB_MAX_HOST was 1000, we'd use a bitmap. Or a better data structure.
 412  */
 413 #define UB_MAX_HOSTS  26
 414 static char ub_hostv[UB_MAX_HOSTS];
 415
 416 #define UB_QLOCK_NUM 5
 417 static spinlock_t ub_qlockv[UB_QLOCK_NUM];
 418 static int ub_qlock_next = 0;
 419
 420 static DEFINE_SPINLOCK(ub_lock);        /* Locks globals and ->openc */
 421
 422 /*
 423  * The id allocator.
 424  *
 425  * This also stores the host for indexing by minor, which is somewhat dirty.
 426  */
 427 static int ub_id_get(void)
 428 {
 429         unsigned long flags;
 430         int i;
 431
 432         spin_lock_irqsave(&ub_lock, flags);
 433         for (i = 0; i < UB_MAX_HOSTS; i++) {
 434                 if (ub_hostv[i] == 0) {
 435                         ub_hostv[i] = 1;
 436                         spin_unlock_irqrestore(&ub_lock, flags);
 437                         return i;
 438                 }
 439         }
 440         spin_unlock_irqrestore(&ub_lock, flags);
 441         return -1;
 442 }
 443
 444 static void ub_id_put(int id)
 445 {
 446         unsigned long flags;
 447
 448         if (id < 0 || id >= UB_MAX_HOSTS) {
 449                 printk(KERN_ERR DRV_NAME ": bad host ID %d\n", id);
 450                 return;
 451         }
 452
 453         spin_lock_irqsave(&ub_lock, flags);
 454         if (ub_hostv[id] == 0) {
 455                 spin_unlock_irqrestore(&ub_lock, flags);
 456                 printk(KERN_ERR DRV_NAME ": freeing free host ID %d\n", id);
 457                 return;
 458         }
 459         ub_hostv[id] = 0;
 460         spin_unlock_irqrestore(&ub_lock, flags);
 461 }
 462
 463 /*
 464  * This is necessitated by the fact that blk_cleanup_queue does not
 465  * necesserily destroy the queue. Instead, it may merely decrease q->refcnt.
 466  * Since our blk_init_queue() passes a spinlock common with ub_dev,
 467  * we have life time issues when ub_cleanup frees ub_dev.
 468  */
 469 static spinlock_t *ub_next_lock(void)
 470 {
 471         unsigned long flags;
 472         spinlock_t *ret;
 473
 474         spin_lock_irqsave(&ub_lock, flags);
 475         ret = &ub_qlockv[ub_qlock_next];
 476         ub_qlock_next = (ub_qlock_next + 1) % UB_QLOCK_NUM;
 477         spin_unlock_irqrestore(&ub_lock, flags);
 478         return ret;
 479 }
 480
 481 /*
 482  * Downcount for deallocation. This rides on two assumptions:
 483  *  - once something is poisoned, its refcount cannot grow
 484  *  - opens cannot happen at this time (del_gendisk was done)
 485  * If the above is true, we can drop the lock, which we need for
 486  * blk_cleanup_queue(): the silly thing may attempt to sleep.
 487  * [Actually, it never needs to sleep for us, but it calls might_sleep()]
 488  */
 489 static void ub_put(struct ub_dev *sc)
 490 {
 491         unsigned long flags;
 492
 493         spin_lock_irqsave(&ub_lock, flags);
 494         --sc->openc;
 495         if (sc->openc == 0 && atomic_read(&sc->poison)) {
 496                 spin_unlock_irqrestore(&ub_lock, flags);
 497                 ub_cleanup(sc);
 498         } else {
 499                 spin_unlock_irqrestore(&ub_lock, flags);
 500         }
 501 }
 502
 503 /*
 504  * Final cleanup and deallocation.
 505  */
 506 static void ub_cleanup(struct ub_dev *sc)
 507 {
 508         struct list_head *p;
 509         struct ub_lun *lun;
 510         struct request_queue *q;
 511
 512         while (!list_empty(&sc->luns)) {
 513                 p = sc->luns.next;
 514                 lun = list_entry(p, struct ub_lun, link);
 515                 list_del(p);
 516
 517                 /* I don't think queue can be NULL. But... Stolen from sx8.c */
 518                 if ((q = lun->disk->queue) != NULL)
 519                         blk_cleanup_queue(q);
 520                 /*
 521                  * If we zero disk->private_data BEFORE put_disk, we have
 522                  * to check for NULL all over the place in open, release,
 523                  * check_media and revalidate, because the block level
 524                  * semaphore is well inside the put_disk.
 525                  * But we cannot zero after the call, because *disk is gone.
 526                  * The sd.c is blatantly racy in this area.
 527                  */
 528                 /* disk->private_data = NULL; */
 529                 put_disk(lun->disk);
 530                 lun->disk = NULL;
 531
 532                 ub_id_put(lun->id);
 533                 kfree(lun);
 534         }
 535
 536         usb_set_intfdata(sc->intf, NULL);
 537         usb_put_intf(sc->intf);
 538         usb_put_dev(sc->dev);
 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(struct request_queue *q)
 627 {
 628         struct ub_lun *lun = q->queuedata;
 629         struct request *rq;
 630
 631         while ((rq = blk_peek_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)) {
 647                 blk_start_request(rq);
 648                 ub_end_rq(rq, DID_NO_CONNECT << 16);
 649                 return 0;
 650         }
 651
 652         if (lun->changed && rq->cmd_type != REQ_TYPE_BLOCK_PC) {
 653                 blk_start_request(rq);
 654                 ub_end_rq(rq, SAM_STAT_CHECK_CONDITION);
 655                 return 0;
 656         }
 657
 658         if (lun->urq.rq != NULL)
 659                 return -1;
 660         if ((cmd = ub_get_cmd(lun)) == NULL)
 661                 return -1;
 662         memset(cmd, 0, sizeof(struct ub_scsi_cmd));
 663
 664         blk_start_request(rq);
 665
 666         urq = &lun->urq;
 667         memset(urq, 0, sizeof(struct ub_request));
 668         urq->rq = rq;
 669
 670         /*
 671          * get scatterlist from block layer
 672          */
 673         sg_init_table(&urq->sgv[0], UB_MAX_REQ_SG);
 674         n_elem = blk_rq_map_sg(lun->disk->queue, rq, &urq->sgv[0]);
 675         if (n_elem < 0) {
 676                 /* Impossible, because blk_rq_map_sg should not hit ENOMEM. */
 677                 printk(KERN_INFO "%s: failed request map (%d)\n",
 678                     lun->name, n_elem);
 679                 goto drop;
 680         }
 681         if (n_elem > UB_MAX_REQ_SG) {   /* Paranoia */
 682                 printk(KERN_WARNING "%s: request with %d segments\n",
 683                     lun->name, n_elem);
 684                 goto drop;
 685         }
 686         urq->nsg = n_elem;
 687
 688         if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
 689                 ub_cmd_build_packet(sc, lun, cmd, urq);
 690         } else {
 691                 ub_cmd_build_block(sc, lun, cmd, urq);
 692         }
 693         cmd->state = UB_CMDST_INIT;
 694         cmd->lun = lun;
 695         cmd->done = ub_rw_cmd_done;
 696         cmd->back = urq;
 697
 698         cmd->tag = sc->tagcnt++;
 699         if (ub_submit_scsi(sc, cmd) != 0)
 700                 goto drop;
 701
 702         return 0;
 703
 704 drop:
 705         ub_put_cmd(lun, cmd);
 706         ub_end_rq(rq, DID_ERROR << 16);
 707         return 0;
 708 }
 709
 710 static void ub_cmd_build_block(struct ub_dev *sc, struct ub_lun *lun,
 711     struct ub_scsi_cmd *cmd, struct ub_request *urq)
 712 {
 713         struct request *rq = urq->rq;
 714         unsigned int block, nblks;
 715
 716         if (rq_data_dir(rq) == WRITE)
 717                 cmd->dir = UB_DIR_WRITE;
 718         else
 719                 cmd->dir = UB_DIR_READ;
 720
 721         cmd->nsg = urq->nsg;
 722         memcpy(cmd->sgv, urq->sgv, sizeof(struct scatterlist) * cmd->nsg);
 723
 724         /*
 725          * build the command
 726          *
 727          * The call to blk_queue_logical_block_size() guarantees that request
 728          * is aligned, but it is given in terms of 512 byte units, always.
 729          */
 730         block = blk_rq_pos(rq) >> lun->capacity.bshift;
 731         nblks = blk_rq_sectors(rq) >> lun->capacity.bshift;
 732
 733         cmd->cdb[0] = (cmd->dir == UB_DIR_READ)? READ_10: WRITE_10;
 734         /* 10-byte uses 4 bytes of LBA: 2147483648KB, 2097152MB, 2048GB */
 735         cmd->cdb[2] = block >> 24;
 736         cmd->cdb[3] = block >> 16;
 737         cmd->cdb[4] = block >> 8;
 738         cmd->cdb[5] = block;
 739         cmd->cdb[7] = nblks >> 8;
 740         cmd->cdb[8] = nblks;
 741         cmd->cdb_len = 10;
 742
 743         cmd->len = blk_rq_bytes(rq);
 744 }
 745
 746 static void ub_cmd_build_packet(struct ub_dev *sc, struct ub_lun *lun,
 747     struct ub_scsi_cmd *cmd, struct ub_request *urq)
 748 {
 749         struct request *rq = urq->rq;
 750
 751         if (blk_rq_bytes(rq) == 0) {
 752                 cmd->dir = UB_DIR_NONE;
 753         } else {
 754                 if (rq_data_dir(rq) == WRITE)
 755                         cmd->dir = UB_DIR_WRITE;
 756                 else
 757                         cmd->dir = UB_DIR_READ;
 758         }
 759
 760         cmd->nsg = urq->nsg;
 761         memcpy(cmd->sgv, urq->sgv, sizeof(struct scatterlist) * cmd->nsg);
 762
 763         memcpy(&cmd->cdb, rq->cmd, rq->cmd_len);
 764         cmd->cdb_len = rq->cmd_len;
 765
 766         cmd->len = blk_rq_bytes(rq);
 767
 768         /*
 769          * To reapply this to every URB is not as incorrect as it looks.
 770          * In return, we avoid any complicated tracking calculations.
 771          */
 772         cmd->timeo = rq->timeout;
 773 }
 774
 775 static void ub_rw_cmd_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 776 {
 777         struct ub_lun *lun = cmd->lun;
 778         struct ub_request *urq = cmd->back;
 779         struct request *rq;
 780         unsigned int scsi_status;
 781
 782         rq = urq->rq;
 783
 784         if (cmd->error == 0) {
 785                 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
 786                         if (cmd->act_len >= rq->resid_len)
 787                                 rq->resid_len = 0;
 788                         else
 789                                 rq->resid_len -= cmd->act_len;
 790                         scsi_status = 0;
 791                 } else {
 792                         if (cmd->act_len != cmd->len) {
 793                                 scsi_status = SAM_STAT_CHECK_CONDITION;
 794                         } else {
 795                                 scsi_status = 0;
 796                         }
 797                 }
 798         } else {
 799                 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
 800                         /* UB_SENSE_SIZE is smaller than SCSI_SENSE_BUFFERSIZE */
 801                         memcpy(rq->sense, sc->top_sense, UB_SENSE_SIZE);
 802                         rq->sense_len = UB_SENSE_SIZE;
 803                         if (sc->top_sense[0] != 0)
 804                                 scsi_status = SAM_STAT_CHECK_CONDITION;
 805                         else
 806                                 scsi_status = DID_ERROR << 16;
 807                 } else {
 808                         if (cmd->error == -EIO &&
 809                             (cmd->key == 0 ||
 810                              cmd->key == MEDIUM_ERROR ||
 811                              cmd->key == UNIT_ATTENTION)) {
 812                                 if (ub_rw_cmd_retry(sc, lun, urq, cmd) == 0)
 813                                         return;
 814                         }
 815                         scsi_status = SAM_STAT_CHECK_CONDITION;
 816                 }
 817         }
 818
 819         urq->rq = NULL;
 820
 821         ub_put_cmd(lun, cmd);
 822         ub_end_rq(rq, scsi_status);
 823         blk_start_queue(lun->disk->queue);
 824 }
 825
 826 static void ub_end_rq(struct request *rq, unsigned int scsi_status)
 827 {
 828         int error;
 829
 830         if (scsi_status == 0) {
 831                 error = 0;
 832         } else {
 833                 error = -EIO;
 834                 rq->errors = scsi_status;
 835         }
 836         __blk_end_request_all(rq, error);
 837 }
 838
 839 static int ub_rw_cmd_retry(struct ub_dev *sc, struct ub_lun *lun,
 840     struct ub_request *urq, struct ub_scsi_cmd *cmd)
 841 {
 842
 843         if (atomic_read(&sc->poison))
 844                 return -ENXIO;
 845
 846         ub_reset_enter(sc, urq->current_try);
 847
 848         if (urq->current_try >= 3)
 849                 return -EIO;
 850         urq->current_try++;
 851
 852         /* Remove this if anyone complains of flooding. */
 853         printk(KERN_DEBUG "%s: dir %c len/act %d/%d "
 854             "[sense %x %02x %02x] retry %d\n",
 855             sc->name, UB_DIR_CHAR(cmd->dir), cmd->len, cmd->act_len,
 856             cmd->key, cmd->asc, cmd->ascq, urq->current_try);
 857
 858         memset(cmd, 0, sizeof(struct ub_scsi_cmd));
 859         ub_cmd_build_block(sc, lun, cmd, urq);
 860
 861         cmd->state = UB_CMDST_INIT;
 862         cmd->lun = lun;
 863         cmd->done = ub_rw_cmd_done;
 864         cmd->back = urq;
 865
 866         cmd->tag = sc->tagcnt++;
 867
 868 #if 0 /* Wasteful */
 869         return ub_submit_scsi(sc, cmd);
 870 #else
 871         ub_cmdq_add(sc, cmd);
 872         return 0;
 873 #endif
 874 }
 875
 876 /*
 877  * Submit a regular SCSI operation (not an auto-sense).
 878  *
 879  * The Iron Law of Good Submit Routine is:
 880  * Zero return - callback is done, Nonzero return - callback is not done.
 881  * No exceptions.
 882  *
 883  * Host is assumed locked.
 884  */
 885 static int ub_submit_scsi(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 886 {
 887
 888         if (cmd->state != UB_CMDST_INIT ||
 889             (cmd->dir != UB_DIR_NONE && cmd->len == 0)) {
 890                 return -EINVAL;
 891         }
 892
 893         ub_cmdq_add(sc, cmd);
 894         /*
 895          * We can call ub_scsi_dispatch(sc) right away here, but it's a little
 896          * safer to jump to a tasklet, in case upper layers do something silly.
 897          */
 898         tasklet_schedule(&sc->tasklet);
 899         return 0;
 900 }
 901
 902 /*
 903  * Submit the first URB for the queued command.
 904  * This function does not deal with queueing in any way.
 905  */
 906 static int ub_scsi_cmd_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 907 {
 908         struct bulk_cb_wrap *bcb;
 909         int rc;
 910
 911         bcb = &sc->work_bcb;
 912
 913         /*
 914          * ``If the allocation length is eighteen or greater, and a device
 915          * server returns less than eithteen bytes of data, the application
 916          * client should assume that the bytes not transferred would have been
 917          * zeroes had the device server returned those bytes.''
 918          *
 919          * We zero sense for all commands so that when a packet request
 920          * fails it does not return a stale sense.
 921          */
 922         memset(&sc->top_sense, 0, UB_SENSE_SIZE);
 923
 924         /* set up the command wrapper */
 925         bcb->Signature = cpu_to_le32(US_BULK_CB_SIGN);
 926         bcb->Tag = cmd->tag;            /* Endianness is not important */
 927         bcb->DataTransferLength = cpu_to_le32(cmd->len);
 928         bcb->Flags = (cmd->dir == UB_DIR_READ) ? 0x80 : 0;
 929         bcb->Lun = (cmd->lun != NULL) ? cmd->lun->num : 0;
 930         bcb->Length = cmd->cdb_len;
 931
 932         /* copy the command payload */
 933         memcpy(bcb->CDB, cmd->cdb, UB_MAX_CDB_SIZE);
 934
 935         UB_INIT_COMPLETION(sc->work_done);
 936
 937         sc->last_pipe = sc->send_bulk_pipe;
 938         usb_fill_bulk_urb(&sc->work_urb, sc->dev, sc->send_bulk_pipe,
 939             bcb, US_BULK_CB_WRAP_LEN, ub_urb_complete, sc);
 940
 941         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
 942                 /* XXX Clear stalls */
 943                 ub_complete(&sc->work_done);
 944                 return rc;
 945         }
 946
 947         sc->work_timer.expires = jiffies + UB_URB_TIMEOUT;
 948         add_timer(&sc->work_timer);
 949
 950         cmd->state = UB_CMDST_CMD;
 951         return 0;
 952 }
 953
 954 /*
 955  * Timeout handler.
 956  */
 957 static void ub_urb_timeout(unsigned long arg)
 958 {
 959         struct ub_dev *sc = (struct ub_dev *) arg;
 960         unsigned long flags;
 961
 962         spin_lock_irqsave(sc->lock, flags);
 963         if (!ub_is_completed(&sc->work_done))
 964                 usb_unlink_urb(&sc->work_urb);
 965         spin_unlock_irqrestore(sc->lock, flags);
 966 }
 967
 968 /*
 969  * Completion routine for the work URB.
 970  *
 971  * This can be called directly from usb_submit_urb (while we have
 972  * the sc->lock taken) and from an interrupt (while we do NOT have
 973  * the sc->lock taken). Therefore, bounce this off to a tasklet.
 974  */
 975 static void ub_urb_complete(struct urb *urb)
 976 {
 977         struct ub_dev *sc = urb->context;
 978
 979         ub_complete(&sc->work_done);
 980         tasklet_schedule(&sc->tasklet);
 981 }
 982
 983 static void ub_scsi_action(unsigned long _dev)
 984 {
 985         struct ub_dev *sc = (struct ub_dev *) _dev;
 986         unsigned long flags;
 987
 988         spin_lock_irqsave(sc->lock, flags);
 989         ub_scsi_dispatch(sc);
 990         spin_unlock_irqrestore(sc->lock, flags);
 991 }
 992
 993 static void ub_scsi_dispatch(struct ub_dev *sc)
 994 {
 995         struct ub_scsi_cmd *cmd;
 996         int rc;
 997
 998         while (!sc->reset && (cmd = ub_cmdq_peek(sc)) != NULL) {
 999                 if (cmd->state == UB_CMDST_DONE) {
1000                         ub_cmdq_pop(sc);
1001                         (*cmd->done)(sc, cmd);
1002                 } else if (cmd->state == UB_CMDST_INIT) {
1003                         if ((rc = ub_scsi_cmd_start(sc, cmd)) == 0)
1004                                 break;
1005                         cmd->error = rc;
1006                         cmd->state = UB_CMDST_DONE;
1007                 } else {
1008                         if (!ub_is_completed(&sc->work_done))
1009                                 break;
1010                         del_timer(&sc->work_timer);
1011                         ub_scsi_urb_compl(sc, cmd);
1012                 }
1013         }
1014 }
1015
1016 static void ub_scsi_urb_compl(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1017 {
1018         struct urb *urb = &sc->work_urb;
1019         struct bulk_cs_wrap *bcs;
1020         int endp;
1021         int len;
1022         int rc;
1023
1024         if (atomic_read(&sc->poison)) {
1025                 ub_state_done(sc, cmd, -ENODEV);
1026                 return;
1027         }
1028
1029         endp = usb_pipeendpoint(sc->last_pipe);
1030         if (usb_pipein(sc->last_pipe))
1031                 endp |= USB_DIR_IN;
1032
1033         if (cmd->state == UB_CMDST_CLEAR) {
1034                 if (urb->status == -EPIPE) {
1035                         /*
1036                          * STALL while clearning STALL.
1037                          * The control pipe clears itself - nothing to do.
1038                          */
1039                         printk(KERN_NOTICE "%s: stall on control pipe\n",
1040                             sc->name);
1041                         goto Bad_End;
1042                 }
1043
1044                 /*
1045                  * We ignore the result for the halt clear.
1046                  */
1047
1048                 usb_reset_endpoint(sc->dev, endp);
1049
1050                 ub_state_sense(sc, cmd);
1051
1052         } else if (cmd->state == UB_CMDST_CLR2STS) {
1053                 if (urb->status == -EPIPE) {
1054                         printk(KERN_NOTICE "%s: stall on control pipe\n",
1055                             sc->name);
1056                         goto Bad_End;
1057                 }
1058
1059                 /*
1060                  * We ignore the result for the halt clear.
1061                  */
1062
1063                 usb_reset_endpoint(sc->dev, endp);
1064
1065                 ub_state_stat(sc, cmd);
1066
1067         } else if (cmd->state == UB_CMDST_CLRRS) {
1068                 if (urb->status == -EPIPE) {
1069                         printk(KERN_NOTICE "%s: stall on control pipe\n",
1070                             sc->name);
1071                         goto Bad_End;
1072                 }
1073
1074                 /*
1075                  * We ignore the result for the halt clear.
1076                  */
1077
1078                 usb_reset_endpoint(sc->dev, endp);
1079
1080                 ub_state_stat_counted(sc, cmd);
1081
1082         } else if (cmd->state == UB_CMDST_CMD) {
1083                 switch (urb->status) {
1084                 case 0:
1085                         break;
1086                 case -EOVERFLOW:
1087                         goto Bad_End;
1088                 case -EPIPE:
1089                         rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
1090                         if (rc != 0) {
1091                                 printk(KERN_NOTICE "%s: "
1092                                     "unable to submit clear (%d)\n",
1093                                     sc->name, rc);
1094                                 /*
1095                                  * This is typically ENOMEM or some other such shit.
1096                                  * Retrying is pointless. Just do Bad End on it...
1097                                  */
1098                                 ub_state_done(sc, cmd, rc);
1099                                 return;
1100                         }
1101                         cmd->state = UB_CMDST_CLEAR;
1102                         return;
1103                 case -ESHUTDOWN:        /* unplug */
1104                 case -EILSEQ:           /* unplug timeout on uhci */
1105                         ub_state_done(sc, cmd, -ENODEV);
1106                         return;
1107                 default:
1108                         goto Bad_End;
1109                 }
1110                 if (urb->actual_length != US_BULK_CB_WRAP_LEN) {
1111                         goto Bad_End;
1112                 }
1113
1114                 if (cmd->dir == UB_DIR_NONE || cmd->nsg < 1) {
1115                         ub_state_stat(sc, cmd);
1116                         return;
1117                 }
1118
1119                 // udelay(125);         // usb-storage has this
1120                 ub_data_start(sc, cmd);
1121
1122         } else if (cmd->state == UB_CMDST_DATA) {
1123                 if (urb->status == -EPIPE) {
1124                         rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
1125                         if (rc != 0) {
1126                                 printk(KERN_NOTICE "%s: "
1127                                     "unable to submit clear (%d)\n",
1128                                     sc->name, rc);
1129                                 ub_state_done(sc, cmd, rc);
1130                                 return;
1131                         }
1132                         cmd->state = UB_CMDST_CLR2STS;
1133                         return;
1134                 }
1135                 if (urb->status == -EOVERFLOW) {
1136                         /*
1137                          * A babble? Failure, but we must transfer CSW now.
1138                          */
1139                         cmd->error = -EOVERFLOW;        /* A cheap trick... */
1140                         ub_state_stat(sc, cmd);
1141                         return;
1142                 }
1143
1144                 if (cmd->dir == UB_DIR_WRITE) {
1145                         /*
1146                          * Do not continue writes in case of a failure.
1147                          * Doing so would cause sectors to be mixed up,
1148                          * which is worse than sectors lost.
1149                          *
1150                          * We must try to read the CSW, or many devices
1151                          * get confused.
1152                          */
1153                         len = urb->actual_length;
1154                         if (urb->status != 0 ||
1155                             len != cmd->sgv[cmd->current_sg].length) {
1156                                 cmd->act_len += len;
1157
1158                                 cmd->error = -EIO;
1159                                 ub_state_stat(sc, cmd);
1160                                 return;
1161                         }
1162
1163                 } else {
1164                         /*
1165                          * If an error occurs on read, we record it, and
1166                          * continue to fetch data in order to avoid bubble.
1167                          *
1168                          * As a small shortcut, we stop if we detect that
1169                          * a CSW mixed into data.
1170                          */
1171                         if (urb->status != 0)
1172                                 cmd->error = -EIO;
1173
1174                         len = urb->actual_length;
1175                         if (urb->status != 0 ||
1176                             len != cmd->sgv[cmd->current_sg].length) {
1177                                 if ((len & 0x1FF) == US_BULK_CS_WRAP_LEN)
1178                                         goto Bad_End;
1179                         }
1180                 }
1181
1182                 cmd->act_len += urb->actual_length;
1183
1184                 if (++cmd->current_sg < cmd->nsg) {
1185                         ub_data_start(sc, cmd);
1186                         return;
1187                 }
1188                 ub_state_stat(sc, cmd);
1189
1190         } else if (cmd->state == UB_CMDST_STAT) {
1191                 if (urb->status == -EPIPE) {
1192                         rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
1193                         if (rc != 0) {
1194                                 printk(KERN_NOTICE "%s: "
1195                                     "unable to submit clear (%d)\n",
1196                                     sc->name, rc);
1197                                 ub_state_done(sc, cmd, rc);
1198                                 return;
1199                         }
1200
1201                         /*
1202                          * Having a stall when getting CSW is an error, so
1203                          * make sure uppper levels are not oblivious to it.
1204                          */
1205                         cmd->error = -EIO;              /* A cheap trick... */
1206
1207                         cmd->state = UB_CMDST_CLRRS;
1208                         return;
1209                 }
1210
1211                 /* Catch everything, including -EOVERFLOW and other nasties. */
1212                 if (urb->status != 0)
1213                         goto Bad_End;
1214
1215                 if (urb->actual_length == 0) {
1216                         ub_state_stat_counted(sc, cmd);
1217                         return;
1218                 }
1219
1220                 /*
1221                  * Check the returned Bulk protocol status.
1222                  * The status block has to be validated first.
1223                  */
1224
1225                 bcs = &sc->work_bcs;
1226
1227                 if (sc->signature == cpu_to_le32(0)) {
1228                         /*
1229                          * This is the first reply, so do not perform the check.
1230                          * Instead, remember the signature the device uses
1231                          * for future checks. But do not allow a nul.
1232                          */
1233                         sc->signature = bcs->Signature;
1234                         if (sc->signature == cpu_to_le32(0)) {
1235                                 ub_state_stat_counted(sc, cmd);
1236                                 return;
1237                         }
1238                 } else {
1239                         if (bcs->Signature != sc->signature) {
1240                                 ub_state_stat_counted(sc, cmd);
1241                                 return;
1242                         }
1243                 }
1244
1245                 if (bcs->Tag != cmd->tag) {
1246                         /*
1247                          * This usually happens when we disagree with the
1248                          * device's microcode about something. For instance,
1249                          * a few of them throw this after timeouts. They buffer
1250                          * commands and reply at commands we timed out before.
1251                          * Without flushing these replies we loop forever.
1252                          */
1253                         ub_state_stat_counted(sc, cmd);
1254                         return;
1255                 }
1256
1257                 if (!sc->bad_resid) {
1258                         len = le32_to_cpu(bcs->Residue);
1259                         if (len != cmd->len - cmd->act_len) {
1260                                 /*
1261                                  * Only start ignoring if this cmd ended well.
1262                                  */
1263                                 if (cmd->len == cmd->act_len) {
1264                                         printk(KERN_NOTICE "%s: "
1265                                             "bad residual %d of %d, ignoring\n",
1266                                             sc->name, len, cmd->len);
1267                                         sc->bad_resid = 1;
1268                                 }
1269                         }
1270                 }
1271
1272                 switch (bcs->Status) {
1273                 case US_BULK_STAT_OK:
1274                         break;
1275                 case US_BULK_STAT_FAIL:
1276                         ub_state_sense(sc, cmd);
1277                         return;
1278                 case US_BULK_STAT_PHASE:
1279                         goto Bad_End;
1280                 default:
1281                         printk(KERN_INFO "%s: unknown CSW status 0x%x\n",
1282                             sc->name, bcs->Status);
1283                         ub_state_done(sc, cmd, -EINVAL);
1284                         return;
1285                 }
1286
1287                 /* Not zeroing error to preserve a babble indicator */
1288                 if (cmd->error != 0) {
1289                         ub_state_sense(sc, cmd);
1290                         return;
1291                 }
1292                 cmd->state = UB_CMDST_DONE;
1293                 ub_cmdq_pop(sc);
1294                 (*cmd->done)(sc, cmd);
1295
1296         } else if (cmd->state == UB_CMDST_SENSE) {
1297                 ub_state_done(sc, cmd, -EIO);
1298
1299         } else {
1300                 printk(KERN_WARNING "%s: wrong command state %d\n",
1301                     sc->name, cmd->state);
1302                 ub_state_done(sc, cmd, -EINVAL);
1303                 return;
1304         }
1305         return;
1306
1307 Bad_End: /* Little Excel is dead */
1308         ub_state_done(sc, cmd, -EIO);
1309 }
1310
1311 /*
1312  * Factorization helper for the command state machine:
1313  * Initiate a data segment transfer.
1314  */
1315 static void ub_data_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1316 {
1317         struct scatterlist *sg = &cmd->sgv[cmd->current_sg];
1318         int pipe;
1319         int rc;
1320
1321         UB_INIT_COMPLETION(sc->work_done);
1322
1323         if (cmd->dir == UB_DIR_READ)
1324                 pipe = sc->recv_bulk_pipe;
1325         else
1326                 pipe = sc->send_bulk_pipe;
1327         sc->last_pipe = pipe;
1328         usb_fill_bulk_urb(&sc->work_urb, sc->dev, pipe, sg_virt(sg),
1329             sg->length, ub_urb_complete, sc);
1330
1331         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
1332                 /* XXX Clear stalls */
1333                 ub_complete(&sc->work_done);
1334                 ub_state_done(sc, cmd, rc);
1335                 return;
1336         }
1337
1338         if (cmd->timeo)
1339                 sc->work_timer.expires = jiffies + cmd->timeo;
1340         else
1341                 sc->work_timer.expires = jiffies + UB_DATA_TIMEOUT;
1342         add_timer(&sc->work_timer);
1343
1344         cmd->state = UB_CMDST_DATA;
1345 }
1346
1347 /*
1348  * Factorization helper for the command state machine:
1349  * Finish the command.
1350  */
1351 static void ub_state_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd, int rc)
1352 {
1353
1354         cmd->error = rc;
1355         cmd->state = UB_CMDST_DONE;
1356         ub_cmdq_pop(sc);
1357         (*cmd->done)(sc, cmd);
1358 }
1359
1360 /*
1361  * Factorization helper for the command state machine:
1362  * Submit a CSW read.
1363  */
1364 static int __ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1365 {
1366         int rc;
1367
1368         UB_INIT_COMPLETION(sc->work_done);
1369
1370         sc->last_pipe = sc->recv_bulk_pipe;
1371         usb_fill_bulk_urb(&sc->work_urb, sc->dev, sc->recv_bulk_pipe,
1372             &sc->work_bcs, US_BULK_CS_WRAP_LEN, ub_urb_complete, sc);
1373
1374         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
1375                 /* XXX Clear stalls */
1376                 ub_complete(&sc->work_done);
1377                 ub_state_done(sc, cmd, rc);
1378                 return -1;
1379         }
1380
1381         if (cmd->timeo)
1382                 sc->work_timer.expires = jiffies + cmd->timeo;
1383         else
1384                 sc->work_timer.expires = jiffies + UB_STAT_TIMEOUT;
1385         add_timer(&sc->work_timer);
1386         return 0;
1387 }
1388
1389 /*
1390  * Factorization helper for the command state machine:
1391  * Submit a CSW read and go to STAT state.
1392  */
1393 static void ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1394 {
1395
1396         if (__ub_state_stat(sc, cmd) != 0)
1397                 return;
1398
1399         cmd->stat_count = 0;
1400         cmd->state = UB_CMDST_STAT;
1401 }
1402
1403 /*
1404  * Factorization helper for the command state machine:
1405  * Submit a CSW read and go to STAT state with counter (along [C] path).
1406  */
1407 static void ub_state_stat_counted(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1408 {
1409
1410         if (++cmd->stat_count >= 4) {
1411                 ub_state_sense(sc, cmd);
1412                 return;
1413         }
1414
1415         if (__ub_state_stat(sc, cmd) != 0)
1416                 return;
1417
1418         cmd->state = UB_CMDST_STAT;
1419 }
1420
1421 /*
1422  * Factorization helper for the command state machine:
1423  * Submit a REQUEST SENSE and go to SENSE state.
1424  */
1425 static void ub_state_sense(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1426 {
1427         struct ub_scsi_cmd *scmd;
1428         struct scatterlist *sg;
1429         int rc;
1430
1431         if (cmd->cdb[0] == REQUEST_SENSE) {
1432                 rc = -EPIPE;
1433                 goto error;
1434         }
1435
1436         scmd = &sc->top_rqs_cmd;
1437         memset(scmd, 0, sizeof(struct ub_scsi_cmd));
1438         scmd->cdb[0] = REQUEST_SENSE;
1439         scmd->cdb[4] = UB_SENSE_SIZE;
1440         scmd->cdb_len = 6;
1441         scmd->dir = UB_DIR_READ;
1442         scmd->state = UB_CMDST_INIT;
1443         scmd->nsg = 1;
1444         sg = &scmd->sgv[0];
1445         sg_init_table(sg, UB_MAX_REQ_SG);
1446         sg_set_page(sg, virt_to_page(sc->top_sense), UB_SENSE_SIZE,
1447                         (unsigned long)sc->top_sense & (PAGE_SIZE-1));
1448         scmd->len = UB_SENSE_SIZE;
1449         scmd->lun = cmd->lun;
1450         scmd->done = ub_top_sense_done;
1451         scmd->back = cmd;
1452
1453         scmd->tag = sc->tagcnt++;
1454
1455         cmd->state = UB_CMDST_SENSE;
1456
1457         ub_cmdq_insert(sc, scmd);
1458         return;
1459
1460 error:
1461         ub_state_done(sc, cmd, rc);
1462 }
1463
1464 /*
1465  * A helper for the command's state machine:
1466  * Submit a stall clear.
1467  */
1468 static int ub_submit_clear_stall(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
1469     int stalled_pipe)
1470 {
1471         int endp;
1472         struct usb_ctrlrequest *cr;
1473         int rc;
1474
1475         endp = usb_pipeendpoint(stalled_pipe);
1476         if (usb_pipein (stalled_pipe))
1477                 endp |= USB_DIR_IN;
1478
1479         cr = &sc->work_cr;
1480         cr->bRequestType = USB_RECIP_ENDPOINT;
1481         cr->bRequest = USB_REQ_CLEAR_FEATURE;
1482         cr->wValue = cpu_to_le16(USB_ENDPOINT_HALT);
1483         cr->wIndex = cpu_to_le16(endp);
1484         cr->wLength = cpu_to_le16(0);
1485
1486         UB_INIT_COMPLETION(sc->work_done);
1487
1488         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->send_ctrl_pipe,
1489             (unsigned char*) cr, NULL, 0, ub_urb_complete, sc);
1490
1491         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
1492                 ub_complete(&sc->work_done);
1493                 return rc;
1494         }
1495
1496         sc->work_timer.expires = jiffies + UB_CTRL_TIMEOUT;
1497         add_timer(&sc->work_timer);
1498         return 0;
1499 }
1500
1501 /*
1502  */
1503 static void ub_top_sense_done(struct ub_dev *sc, struct ub_scsi_cmd *scmd)
1504 {
1505         unsigned char *sense = sc->top_sense;
1506         struct ub_scsi_cmd *cmd;
1507
1508         /*
1509          * Find the command which triggered the unit attention or a check,
1510          * save the sense into it, and advance its state machine.
1511          */
1512         if ((cmd = ub_cmdq_peek(sc)) == NULL) {
1513                 printk(KERN_WARNING "%s: sense done while idle\n", sc->name);
1514                 return;
1515         }
1516         if (cmd != scmd->back) {
1517                 printk(KERN_WARNING "%s: "
1518                     "sense done for wrong command 0x%x\n",
1519                     sc->name, cmd->tag);
1520                 return;
1521         }
1522         if (cmd->state != UB_CMDST_SENSE) {
1523                 printk(KERN_WARNING "%s: sense done with bad cmd state %d\n",
1524                     sc->name, cmd->state);
1525                 return;
1526         }
1527
1528         /*
1529          * Ignoring scmd->act_len, because the buffer was pre-zeroed.
1530          */
1531         cmd->key = sense[2] & 0x0F;
1532         cmd->asc = sense[12];
1533         cmd->ascq = sense[13];
1534
1535         ub_scsi_urb_compl(sc, cmd);
1536 }
1537
1538 /*
1539  * Reset management
1540  */
1541
1542 static void ub_reset_enter(struct ub_dev *sc, int try)
1543 {
1544
1545         if (sc->reset) {
1546                 /* This happens often on multi-LUN devices. */
1547                 return;
1548         }
1549         sc->reset = try + 1;
1550
1551 #if 0 /* Not needed because the disconnect waits for us. */
1552         unsigned long flags;
1553         spin_lock_irqsave(&ub_lock, flags);
1554         sc->openc++;
1555         spin_unlock_irqrestore(&ub_lock, flags);
1556 #endif
1557
1558 #if 0 /* We let them stop themselves. */
1559         struct ub_lun *lun;
1560         list_for_each_entry(lun, &sc->luns, link) {
1561                 blk_stop_queue(lun->disk->queue);
1562         }
1563 #endif
1564
1565         schedule_work(&sc->reset_work);
1566 }
1567
1568 static void ub_reset_task(struct work_struct *work)
1569 {
1570         struct ub_dev *sc = container_of(work, struct ub_dev, reset_work);
1571         unsigned long flags;
1572         struct ub_lun *lun;
1573         int rc;
1574
1575         if (!sc->reset) {
1576                 printk(KERN_WARNING "%s: Running reset unrequested\n",
1577                     sc->name);
1578                 return;
1579         }
1580
1581         if (atomic_read(&sc->poison)) {
1582                 ;
1583         } else if ((sc->reset & 1) == 0) {
1584                 ub_sync_reset(sc);
1585                 msleep(700);    /* usb-storage sleeps 6s (!) */
1586                 ub_probe_clear_stall(sc, sc->recv_bulk_pipe);
1587                 ub_probe_clear_stall(sc, sc->send_bulk_pipe);
1588         } else if (sc->dev->actconfig->desc.bNumInterfaces != 1) {
1589                 ;
1590         } else {
1591                 rc = usb_lock_device_for_reset(sc->dev, sc->intf);
1592                 if (rc < 0) {
1593                         printk(KERN_NOTICE
1594                             "%s: usb_lock_device_for_reset failed (%d)\n",
1595                             sc->name, rc);
1596                 } else {
1597                         rc = usb_reset_device(sc->dev);
1598                         if (rc < 0) {
1599                                 printk(KERN_NOTICE "%s: "
1600                                     "usb_lock_device_for_reset failed (%d)\n",
1601                                     sc->name, rc);
1602                         }
1603                         usb_unlock_device(sc->dev);
1604                 }
1605         }
1606
1607         /*
1608          * In theory, no commands can be running while reset is active,
1609          * so nobody can ask for another reset, and so we do not need any
1610          * queues of resets or anything. We do need a spinlock though,
1611          * to interact with block layer.
1612          */
1613         spin_lock_irqsave(sc->lock, flags);
1614         sc->reset = 0;
1615         tasklet_schedule(&sc->tasklet);
1616         list_for_each_entry(lun, &sc->luns, link) {
1617                 blk_start_queue(lun->disk->queue);
1618         }
1619         wake_up(&sc->reset_wait);
1620         spin_unlock_irqrestore(sc->lock, flags);
1621 }
1622
1623 /*
1624  * XXX Reset brackets are too much hassle to implement, so just stub them
1625  * in order to prevent forced unbinding (which deadlocks solid when our
1626  * ->disconnect method waits for the reset to complete and this kills keventd).
1627  *
1628  * XXX Tell Alan to move usb_unlock_device inside of usb_reset_device,
1629  * or else the post_reset is invoked, and restats I/O on a locked device.
1630  */
1631 static int ub_pre_reset(struct usb_interface *iface) {
1632         return 0;
1633 }
1634
1635 static int ub_post_reset(struct usb_interface *iface) {
1636         return 0;
1637 }
1638
1639 /*
1640  * This is called from a process context.
1641  */
1642 static void ub_revalidate(struct ub_dev *sc, struct ub_lun *lun)
1643 {
1644
1645         lun->readonly = 0;      /* XXX Query this from the device */
1646
1647         lun->capacity.nsec = 0;
1648         lun->capacity.bsize = 512;
1649         lun->capacity.bshift = 0;
1650
1651         if (ub_sync_tur(sc, lun) != 0)
1652                 return;                 /* Not ready */
1653         lun->changed = 0;
1654
1655         if (ub_sync_read_cap(sc, lun, &lun->capacity) != 0) {
1656                 /*
1657                  * The retry here means something is wrong, either with the
1658                  * device, with the transport, or with our code.
1659                  * We keep this because sd.c has retries for capacity.
1660                  */
1661                 if (ub_sync_read_cap(sc, lun, &lun->capacity) != 0) {
1662                         lun->capacity.nsec = 0;
1663                         lun->capacity.bsize = 512;
1664                         lun->capacity.bshift = 0;
1665                 }
1666         }
1667 }
1668
1669 /*
1670  * The open funcion.
1671  * This is mostly needed to keep refcounting, but also to support
1672  * media checks on removable media drives.
1673  */
1674 static int ub_bd_open(struct block_device *bdev, fmode_t mode)
1675 {
1676         struct ub_lun *lun = bdev->bd_disk->private_data;
1677         struct ub_dev *sc = lun->udev;
1678         unsigned long flags;
1679         int rc;
1680
1681         spin_lock_irqsave(&ub_lock, flags);
1682         if (atomic_read(&sc->poison)) {
1683                 spin_unlock_irqrestore(&ub_lock, flags);
1684                 return -ENXIO;
1685         }
1686         sc->openc++;
1687         spin_unlock_irqrestore(&ub_lock, flags);
1688
1689         if (lun->removable || lun->readonly)
1690                 check_disk_change(bdev);
1691
1692         /*
1693          * The sd.c considers ->media_present and ->changed not equivalent,
1694          * under some pretty murky conditions (a failure of READ CAPACITY).
1695          * We may need it one day.
1696          */
1697         if (lun->removable && lun->changed && !(mode & FMODE_NDELAY)) {
1698                 rc = -ENOMEDIUM;
1699                 goto err_open;
1700         }
1701
1702         if (lun->readonly && (mode & FMODE_WRITE)) {
1703                 rc = -EROFS;
1704                 goto err_open;
1705         }
1706
1707         return 0;
1708
1709 err_open:
1710         ub_put(sc);
1711         return rc;
1712 }
1713
1714 static int ub_bd_unlocked_open(struct block_device *bdev, fmode_t mode)
1715 {
1716         int ret;
1717
1718         lock_kernel();
1719         ret = ub_bd_open(bdev, mode);
1720         unlock_kernel();
1721
1722         return ret;
1723 }
1724
1725
1726 /*
1727  */
1728 static int ub_bd_release(struct gendisk *disk, fmode_t mode)
1729 {
1730         struct ub_lun *lun = disk->private_data;
1731         struct ub_dev *sc = lun->udev;
1732
1733         lock_kernel();
1734         ub_put(sc);
1735         unlock_kernel();
1736
1737         return 0;
1738 }
1739
1740 /*
1741  * The ioctl interface.
1742  */
1743 static int ub_bd_ioctl(struct block_device *bdev, fmode_t mode,
1744     unsigned int cmd, unsigned long arg)
1745 {
1746         struct gendisk *disk = bdev->bd_disk;
1747         void __user *usermem = (void __user *) arg;
1748         int ret;
1749
1750         lock_kernel();
1751         ret = scsi_cmd_ioctl(disk->queue, disk, mode, cmd, usermem);
1752         unlock_kernel();
1753
1754         return ret;
1755 }
1756
1757 /*
1758  * This is called by check_disk_change if we reported a media change.
1759  * The main onjective here is to discover the features of the media such as
1760  * the capacity, read-only status, etc. USB storage generally does not
1761  * need to be spun up, but if we needed it, this would be the place.
1762  *
1763  * This call can sleep.
1764  *
1765  * The return code is not used.
1766  */
1767 static int ub_bd_revalidate(struct gendisk *disk)
1768 {
1769         struct ub_lun *lun = disk->private_data;
1770
1771         ub_revalidate(lun->udev, lun);
1772
1773         /* XXX Support sector size switching like in sr.c */
1774         blk_queue_logical_block_size(disk->queue, lun->capacity.bsize);
1775         set_capacity(disk, lun->capacity.nsec);
1776         // set_disk_ro(sdkp->disk, lun->readonly);
1777
1778         return 0;
1779 }
1780
1781 /*
1782  * The check is called by the block layer to verify if the media
1783  * is still available. It is supposed to be harmless, lightweight and
1784  * non-intrusive in case the media was not changed.
1785  *
1786  * This call can sleep.
1787  *
1788  * The return code is bool!
1789  */
1790 static int ub_bd_media_changed(struct gendisk *disk)
1791 {
1792         struct ub_lun *lun = disk->private_data;
1793
1794         if (!lun->removable)
1795                 return 0;
1796
1797         /*
1798          * We clean checks always after every command, so this is not
1799          * as dangerous as it looks. If the TEST_UNIT_READY fails here,
1800          * the device is actually not ready with operator or software
1801          * intervention required. One dangerous item might be a drive which
1802          * spins itself down, and come the time to write dirty pages, this
1803          * will fail, then block layer discards the data. Since we never
1804          * spin drives up, such devices simply cannot be used with ub anyway.
1805          */
1806         if (ub_sync_tur(lun->udev, lun) != 0) {
1807                 lun->changed = 1;
1808                 return 1;
1809         }
1810
1811         return lun->changed;
1812 }
1813
1814 static const struct block_device_operations ub_bd_fops = {
1815         .owner          = THIS_MODULE,
1816         .open           = ub_bd_unlocked_open,
1817         .release        = ub_bd_release,
1818         .ioctl          = ub_bd_ioctl,
1819         .media_changed  = ub_bd_media_changed,
1820         .revalidate_disk = ub_bd_revalidate,
1821 };
1822
1823 /*
1824  * Common ->done routine for commands executed synchronously.
1825  */
1826 static void ub_probe_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1827 {
1828         struct completion *cop = cmd->back;
1829         complete(cop);
1830 }
1831
1832 /*
1833  * Test if the device has a check condition on it, synchronously.
1834  */
1835 static int ub_sync_tur(struct ub_dev *sc, struct ub_lun *lun)
1836 {
1837         struct ub_scsi_cmd *cmd;
1838         enum { ALLOC_SIZE = sizeof(struct ub_scsi_cmd) };
1839         unsigned long flags;
1840         struct completion compl;
1841         int rc;
1842
1843         init_completion(&compl);
1844
1845         rc = -ENOMEM;
1846         if ((cmd = kzalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
1847                 goto err_alloc;
1848
1849         cmd->cdb[0] = TEST_UNIT_READY;
1850         cmd->cdb_len = 6;
1851         cmd->dir = UB_DIR_NONE;
1852         cmd->state = UB_CMDST_INIT;
1853         cmd->lun = lun;                 /* This may be NULL, but that's ok */
1854         cmd->done = ub_probe_done;
1855         cmd->back = &compl;
1856
1857         spin_lock_irqsave(sc->lock, flags);
1858         cmd->tag = sc->tagcnt++;
1859
1860         rc = ub_submit_scsi(sc, cmd);
1861         spin_unlock_irqrestore(sc->lock, flags);
1862
1863         if (rc != 0)
1864                 goto err_submit;
1865
1866         wait_for_completion(&compl);
1867
1868         rc = cmd->error;
1869
1870         if (rc == -EIO && cmd->key != 0)        /* Retries for benh's key */
1871                 rc = cmd->key;
1872
1873 err_submit:
1874         kfree(cmd);
1875 err_alloc:
1876         return rc;
1877 }
1878
1879 /*
1880  * Read the SCSI capacity synchronously (for probing).
1881  */
1882 static int ub_sync_read_cap(struct ub_dev *sc, struct ub_lun *lun,
1883     struct ub_capacity *ret)
1884 {
1885         struct ub_scsi_cmd *cmd;
1886         struct scatterlist *sg;
1887         char *p;
1888         enum { ALLOC_SIZE = sizeof(struct ub_scsi_cmd) + 8 };
1889         unsigned long flags;
1890         unsigned int bsize, shift;
1891         unsigned long nsec;
1892         struct completion compl;
1893         int rc;
1894
1895         init_completion(&compl);
1896
1897         rc = -ENOMEM;
1898         if ((cmd = kzalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
1899                 goto err_alloc;
1900         p = (char *)cmd + sizeof(struct ub_scsi_cmd);
1901
1902         cmd->cdb[0] = 0x25;
1903         cmd->cdb_len = 10;
1904         cmd->dir = UB_DIR_READ;
1905         cmd->state = UB_CMDST_INIT;
1906         cmd->nsg = 1;
1907         sg = &cmd->sgv[0];
1908         sg_init_table(sg, UB_MAX_REQ_SG);
1909         sg_set_page(sg, virt_to_page(p), 8, (unsigned long)p & (PAGE_SIZE-1));
1910         cmd->len = 8;
1911         cmd->lun = lun;
1912         cmd->done = ub_probe_done;
1913         cmd->back = &compl;
1914
1915         spin_lock_irqsave(sc->lock, flags);
1916         cmd->tag = sc->tagcnt++;
1917
1918         rc = ub_submit_scsi(sc, cmd);
1919         spin_unlock_irqrestore(sc->lock, flags);
1920
1921         if (rc != 0)
1922                 goto err_submit;
1923
1924         wait_for_completion(&compl);
1925
1926         if (cmd->error != 0) {
1927                 rc = -EIO;
1928                 goto err_read;
1929         }
1930         if (cmd->act_len != 8) {
1931                 rc = -EIO;
1932                 goto err_read;
1933         }
1934
1935         /* sd.c special-cases sector size of 0 to mean 512. Needed? Safe? */
1936         nsec = be32_to_cpu(*(__be32 *)p) + 1;
1937         bsize = be32_to_cpu(*(__be32 *)(p + 4));
1938         switch (bsize) {
1939         case 512:       shift = 0;      break;
1940         case 1024:      shift = 1;      break;
1941         case 2048:      shift = 2;      break;
1942         case 4096:      shift = 3;      break;
1943         default:
1944                 rc = -EDOM;
1945                 goto err_inv_bsize;
1946         }
1947
1948         ret->bsize = bsize;
1949         ret->bshift = shift;
1950         ret->nsec = nsec << shift;
1951         rc = 0;
1952
1953 err_inv_bsize:
1954 err_read:
1955 err_submit:
1956         kfree(cmd);
1957 err_alloc:
1958         return rc;
1959 }
1960
1961 /*
1962  */
1963 static void ub_probe_urb_complete(struct urb *urb)
1964 {
1965         struct completion *cop = urb->context;
1966         complete(cop);
1967 }
1968
1969 static void ub_probe_timeout(unsigned long arg)
1970 {
1971         struct completion *cop = (struct completion *) arg;
1972         complete(cop);
1973 }
1974
1975 /*
1976  * Reset with a Bulk reset.
1977  */
1978 static int ub_sync_reset(struct ub_dev *sc)
1979 {
1980         int ifnum = sc->intf->cur_altsetting->desc.bInterfaceNumber;
1981         struct usb_ctrlrequest *cr;
1982         struct completion compl;
1983         struct timer_list timer;
1984         int rc;
1985
1986         init_completion(&compl);
1987
1988         cr = &sc->work_cr;
1989         cr->bRequestType = USB_TYPE_CLASS | USB_RECIP_INTERFACE;
1990         cr->bRequest = US_BULK_RESET_REQUEST;
1991         cr->wValue = cpu_to_le16(0);
1992         cr->wIndex = cpu_to_le16(ifnum);
1993         cr->wLength = cpu_to_le16(0);
1994
1995         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->send_ctrl_pipe,
1996             (unsigned char*) cr, NULL, 0, ub_probe_urb_complete, &compl);
1997
1998         if ((rc = usb_submit_urb(&sc->work_urb, GFP_KERNEL)) != 0) {
1999                 printk(KERN_WARNING
2000                      "%s: Unable to submit a bulk reset (%d)\n", sc->name, rc);
2001                 return rc;
2002         }
2003
2004         init_timer(&timer);
2005         timer.function = ub_probe_timeout;
2006         timer.data = (unsigned long) &compl;
2007         timer.expires = jiffies + UB_CTRL_TIMEOUT;
2008         add_timer(&timer);
2009
2010         wait_for_completion(&compl);
2011
2012         del_timer_sync(&timer);
2013         usb_kill_urb(&sc->work_urb);
2014
2015         return sc->work_urb.status;
2016 }
2017
2018 /*
2019  * Get number of LUNs by the way of Bulk GetMaxLUN command.
2020  */
2021 static int ub_sync_getmaxlun(struct ub_dev *sc)
2022 {
2023         int ifnum = sc->intf->cur_altsetting->desc.bInterfaceNumber;
2024         unsigned char *p;
2025         enum { ALLOC_SIZE = 1 };
2026         struct usb_ctrlrequest *cr;
2027         struct completion compl;
2028         struct timer_list timer;
2029         int nluns;
2030         int rc;
2031
2032         init_completion(&compl);
2033
2034         rc = -ENOMEM;
2035         if ((p = kmalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
2036                 goto err_alloc;
2037         *p = 55;
2038
2039         cr = &sc->work_cr;
2040         cr->bRequestType = USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE;
2041         cr->bRequest = US_BULK_GET_MAX_LUN;
2042         cr->wValue = cpu_to_le16(0);
2043         cr->wIndex = cpu_to_le16(ifnum);
2044         cr->wLength = cpu_to_le16(1);
2045
2046         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->recv_ctrl_pipe,
2047             (unsigned char*) cr, p, 1, ub_probe_urb_complete, &compl);
2048
2049         if ((rc = usb_submit_urb(&sc->work_urb, GFP_KERNEL)) != 0)
2050                 goto err_submit;
2051
2052         init_timer(&timer);
2053         timer.function = ub_probe_timeout;
2054         timer.data = (unsigned long) &compl;
2055         timer.expires = jiffies + UB_CTRL_TIMEOUT;
2056         add_timer(&timer);
2057
2058         wait_for_completion(&compl);
2059
2060         del_timer_sync(&timer);
2061         usb_kill_urb(&sc->work_urb);
2062
2063         if ((rc = sc->work_urb.status) < 0)
2064                 goto err_io;
2065
2066         if (sc->work_urb.actual_length != 1) {
2067                 nluns = 0;
2068         } else {
2069                 if ((nluns = *p) == 55) {
2070                         nluns = 0;
2071                 } else {
2072                         /* GetMaxLUN returns the maximum LUN number */
2073                         nluns += 1;
2074                         if (nluns > UB_MAX_LUNS)
2075                                 nluns = UB_MAX_LUNS;
2076                 }
2077         }
2078
2079         kfree(p);
2080         return nluns;
2081
2082 err_io:
2083 err_submit:
2084         kfree(p);
2085 err_alloc:
2086         return rc;
2087 }
2088
2089 /*
2090  * Clear initial stalls.
2091  */
2092 static int ub_probe_clear_stall(struct ub_dev *sc, int stalled_pipe)
2093 {
2094         int endp;
2095         struct usb_ctrlrequest *cr;
2096         struct completion compl;
2097         struct timer_list timer;
2098         int rc;
2099
2100         init_completion(&compl);
2101
2102         endp = usb_pipeendpoint(stalled_pipe);
2103         if (usb_pipein (stalled_pipe))
2104                 endp |= USB_DIR_IN;
2105
2106         cr = &sc->work_cr;
2107         cr->bRequestType = USB_RECIP_ENDPOINT;
2108         cr->bRequest = USB_REQ_CLEAR_FEATURE;
2109         cr->wValue = cpu_to_le16(USB_ENDPOINT_HALT);
2110         cr->wIndex = cpu_to_le16(endp);
2111         cr->wLength = cpu_to_le16(0);
2112
2113         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->send_ctrl_pipe,
2114             (unsigned char*) cr, NULL, 0, ub_probe_urb_complete, &compl);
2115
2116         if ((rc = usb_submit_urb(&sc->work_urb, GFP_KERNEL)) != 0) {
2117                 printk(KERN_WARNING
2118                      "%s: Unable to submit a probe clear (%d)\n", sc->name, rc);
2119                 return rc;
2120         }
2121
2122         init_timer(&timer);
2123         timer.function = ub_probe_timeout;
2124         timer.data = (unsigned long) &compl;
2125         timer.expires = jiffies + UB_CTRL_TIMEOUT;
2126         add_timer(&timer);
2127
2128         wait_for_completion(&compl);
2129
2130         del_timer_sync(&timer);
2131         usb_kill_urb(&sc->work_urb);
2132
2133         usb_reset_endpoint(sc->dev, endp);
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 (usb_endpoint_xfer_bulk(ep)) {
2160                         /* BULK in or out? */
2161                         if (usb_endpoint_dir_in(ep)) {
2162                                 if (ep_in == NULL)
2163                                         ep_in = ep;
2164                         } else {
2165                                 if (ep_out == NULL)
2166                                         ep_out = ep;
2167                         }
2168                 }
2169         }
2170
2171         if (ep_in == NULL || ep_out == NULL) {
2172                 printk(KERN_NOTICE "%s: failed endpoint check\n", sc->name);
2173                 return -ENODEV;
2174         }
2175
2176         /* Calculate and store the pipe values */
2177         sc->send_ctrl_pipe = usb_sndctrlpipe(dev, 0);
2178         sc->recv_ctrl_pipe = usb_rcvctrlpipe(dev, 0);
2179         sc->send_bulk_pipe = usb_sndbulkpipe(dev,
2180                 usb_endpoint_num(ep_out));
2181         sc->recv_bulk_pipe = usb_rcvbulkpipe(dev,
2182                 usb_endpoint_num(ep_in));
2183
2184         return 0;
2185 }
2186
2187 /*
2188  * Probing is done in the process context, which allows us to cheat
2189  * and not to build a state machine for the discovery.
2190  */
2191 static int ub_probe(struct usb_interface *intf,
2192     const struct usb_device_id *dev_id)
2193 {
2194         struct ub_dev *sc;
2195         int nluns;
2196         int rc;
2197         int i;
2198
2199         if (usb_usual_check_type(dev_id, USB_US_TYPE_UB))
2200                 return -ENXIO;
2201
2202         rc = -ENOMEM;
2203         if ((sc = kzalloc(sizeof(struct ub_dev), GFP_KERNEL)) == NULL)
2204                 goto err_core;
2205         sc->lock = ub_next_lock();
2206         INIT_LIST_HEAD(&sc->luns);
2207         usb_init_urb(&sc->work_urb);
2208         tasklet_init(&sc->tasklet, ub_scsi_action, (unsigned long)sc);
2209         atomic_set(&sc->poison, 0);
2210         INIT_WORK(&sc->reset_work, ub_reset_task);
2211         init_waitqueue_head(&sc->reset_wait);
2212
2213         init_timer(&sc->work_timer);
2214         sc->work_timer.data = (unsigned long) sc;
2215         sc->work_timer.function = ub_urb_timeout;
2216
2217         ub_init_completion(&sc->work_done);
2218         sc->work_done.done = 1;         /* A little yuk, but oh well... */
2219
2220         sc->dev = interface_to_usbdev(intf);
2221         sc->intf = intf;
2222         // sc->ifnum = intf->cur_altsetting->desc.bInterfaceNumber;
2223         usb_set_intfdata(intf, sc);
2224         usb_get_dev(sc->dev);
2225         /*
2226          * Since we give the interface struct to the block level through
2227          * disk->driverfs_dev, we have to pin it. Otherwise, block_uevent
2228          * oopses on close after a disconnect (kernels 2.6.16 and up).
2229          */
2230         usb_get_intf(sc->intf);
2231
2232         snprintf(sc->name, 12, DRV_NAME "(%d.%d)",
2233             sc->dev->bus->busnum, sc->dev->devnum);
2234
2235         /* XXX Verify that we can handle the device (from descriptors) */
2236
2237         if (ub_get_pipes(sc, sc->dev, intf) != 0)
2238                 goto err_dev_desc;
2239
2240         /*
2241          * At this point, all USB initialization is done, do upper layer.
2242          * We really hate halfway initialized structures, so from the
2243          * invariants perspective, this ub_dev is fully constructed at
2244          * this point.
2245          */
2246
2247         /*
2248          * This is needed to clear toggles. It is a problem only if we do
2249          * `rmmod ub && modprobe ub` without disconnects, but we like that.
2250          */
2251 #if 0 /* iPod Mini fails if we do this (big white iPod works) */
2252         ub_probe_clear_stall(sc, sc->recv_bulk_pipe);
2253         ub_probe_clear_stall(sc, sc->send_bulk_pipe);
2254 #endif
2255
2256         /*
2257          * The way this is used by the startup code is a little specific.
2258          * A SCSI check causes a USB stall. Our common case code sees it
2259          * and clears the check, after which the device is ready for use.
2260          * But if a check was not present, any command other than
2261          * TEST_UNIT_READY ends with a lockup (including REQUEST_SENSE).
2262          *
2263          * If we neglect to clear the SCSI check, the first real command fails
2264          * (which is the capacity readout). We clear that and retry, but why
2265          * causing spurious retries for no reason.
2266          *
2267          * Revalidation may start with its own TEST_UNIT_READY, but that one
2268          * has to succeed, so we clear checks with an additional one here.
2269          * In any case it's not our business how revaliadation is implemented.
2270          */
2271         for (i = 0; i < 3; i++) {  /* Retries for the schwag key from KS'04 */
2272                 if ((rc = ub_sync_tur(sc, NULL)) <= 0) break;
2273                 if (rc != 0x6) break;
2274                 msleep(10);
2275         }
2276
2277         nluns = 1;
2278         for (i = 0; i < 3; i++) {
2279                 if ((rc = ub_sync_getmaxlun(sc)) < 0)
2280                         break;
2281                 if (rc != 0) {
2282                         nluns = rc;
2283                         break;
2284                 }
2285                 msleep(100);
2286         }
2287
2288         for (i = 0; i < nluns; i++) {
2289                 ub_probe_lun(sc, i);
2290         }
2291         return 0;
2292
2293 err_dev_desc:
2294         usb_set_intfdata(intf, NULL);
2295         usb_put_intf(sc->intf);
2296         usb_put_dev(sc->dev);
2297         kfree(sc);
2298 err_core:
2299         return rc;
2300 }
2301
2302 static int ub_probe_lun(struct ub_dev *sc, int lnum)
2303 {
2304         struct ub_lun *lun;
2305         struct request_queue *q;
2306         struct gendisk *disk;
2307         int rc;
2308
2309         rc = -ENOMEM;
2310         if ((lun = kzalloc(sizeof(struct ub_lun), GFP_KERNEL)) == NULL)
2311                 goto err_alloc;
2312         lun->num = lnum;
2313
2314         rc = -ENOSR;
2315         if ((lun->id = ub_id_get()) == -1)
2316                 goto err_id;
2317
2318         lun->udev = sc;
2319
2320         snprintf(lun->name, 16, DRV_NAME "%c(%d.%d.%d)",
2321             lun->id + 'a', sc->dev->bus->busnum, sc->dev->devnum, lun->num);
2322
2323         lun->removable = 1;             /* XXX Query this from the device */
2324         lun->changed = 1;               /* ub_revalidate clears only */
2325         ub_revalidate(sc, lun);
2326
2327         rc = -ENOMEM;
2328         if ((disk = alloc_disk(UB_PARTS_PER_LUN)) == NULL)
2329                 goto err_diskalloc;
2330
2331         sprintf(disk->disk_name, DRV_NAME "%c", lun->id + 'a');
2332         disk->major = UB_MAJOR;
2333         disk->first_minor = lun->id * UB_PARTS_PER_LUN;
2334         disk->fops = &ub_bd_fops;
2335         disk->private_data = lun;
2336         disk->driverfs_dev = &sc->intf->dev;
2337
2338         rc = -ENOMEM;
2339         if ((q = blk_init_queue(ub_request_fn, sc->lock)) == NULL)
2340                 goto err_blkqinit;
2341
2342         disk->queue = q;
2343
2344         blk_queue_bounce_limit(q, BLK_BOUNCE_HIGH);
2345         blk_queue_max_segments(q, UB_MAX_REQ_SG);
2346         blk_queue_segment_boundary(q, 0xffffffff);      /* Dubious. */
2347         blk_queue_max_hw_sectors(q, UB_MAX_SECTORS);
2348         blk_queue_logical_block_size(q, lun->capacity.bsize);
2349
2350         lun->disk = disk;
2351         q->queuedata = lun;
2352         list_add(&lun->link, &sc->luns);
2353
2354         set_capacity(disk, lun->capacity.nsec);
2355         if (lun->removable)
2356                 disk->flags |= GENHD_FL_REMOVABLE;
2357
2358         add_disk(disk);
2359
2360         return 0;
2361
2362 err_blkqinit:
2363         put_disk(disk);
2364 err_diskalloc:
2365         ub_id_put(lun->id);
2366 err_id:
2367         kfree(lun);
2368 err_alloc:
2369         return rc;
2370 }
2371
2372 static void ub_disconnect(struct usb_interface *intf)
2373 {
2374         struct ub_dev *sc = usb_get_intfdata(intf);
2375         struct ub_lun *lun;
2376         unsigned long flags;
2377
2378         /*
2379          * Prevent ub_bd_release from pulling the rug from under us.
2380          * XXX This is starting to look like a kref.
2381          * XXX Why not to take this ref at probe time?
2382          */
2383         spin_lock_irqsave(&ub_lock, flags);
2384         sc->openc++;
2385         spin_unlock_irqrestore(&ub_lock, flags);
2386
2387         /*
2388          * Fence stall clearings, operations triggered by unlinkings and so on.
2389          * We do not attempt to unlink any URBs, because we do not trust the
2390          * unlink paths in HC drivers. Also, we get -84 upon disconnect anyway.
2391          */
2392         atomic_set(&sc->poison, 1);
2393
2394         /*
2395          * Wait for reset to end, if any.
2396          */
2397         wait_event(sc->reset_wait, !sc->reset);
2398
2399         /*
2400          * Blow away queued commands.
2401          *
2402          * Actually, this never works, because before we get here
2403          * the HCD terminates outstanding URB(s). It causes our
2404          * SCSI command queue to advance, commands fail to submit,
2405          * and the whole queue drains. So, we just use this code to
2406          * print warnings.
2407          */
2408         spin_lock_irqsave(sc->lock, flags);
2409         {
2410                 struct ub_scsi_cmd *cmd;
2411                 int cnt = 0;
2412                 while ((cmd = ub_cmdq_peek(sc)) != NULL) {
2413                         cmd->error = -ENOTCONN;
2414                         cmd->state = UB_CMDST_DONE;
2415                         ub_cmdq_pop(sc);
2416                         (*cmd->done)(sc, cmd);
2417                         cnt++;
2418                 }
2419                 if (cnt != 0) {
2420                         printk(KERN_WARNING "%s: "
2421                             "%d was queued after shutdown\n", sc->name, cnt);
2422                 }
2423         }
2424         spin_unlock_irqrestore(sc->lock, flags);
2425
2426         /*
2427          * Unregister the upper layer.
2428          */
2429         list_for_each_entry(lun, &sc->luns, link) {
2430                 del_gendisk(lun->disk);
2431                 /*
2432                  * I wish I could do:
2433                  *    queue_flag_set(QUEUE_FLAG_DEAD, q);
2434                  * As it is, we rely on our internal poisoning and let
2435                  * the upper levels to spin furiously failing all the I/O.
2436                  */
2437         }
2438
2439         /*
2440          * Testing for -EINPROGRESS is always a bug, so we are bending
2441          * the rules a little.
2442          */
2443         spin_lock_irqsave(sc->lock, flags);
2444         if (sc->work_urb.status == -EINPROGRESS) {      /* janitors: ignore */
2445                 printk(KERN_WARNING "%s: "
2446                     "URB is active after disconnect\n", sc->name);
2447         }
2448         spin_unlock_irqrestore(sc->lock, flags);
2449
2450         /*
2451          * There is virtually no chance that other CPU runs a timeout so long
2452          * after ub_urb_complete should have called del_timer, but only if HCD
2453          * didn't forget to deliver a callback on unlink.
2454          */
2455         del_timer_sync(&sc->work_timer);
2456
2457         /*
2458          * At this point there must be no commands coming from anyone
2459          * and no URBs left in transit.
2460          */
2461
2462         ub_put(sc);
2463 }
2464
2465 static struct usb_driver ub_driver = {
2466         .name =         "ub",
2467         .probe =        ub_probe,
2468         .disconnect =   ub_disconnect,
2469         .id_table =     ub_usb_ids,
2470         .pre_reset =    ub_pre_reset,
2471         .post_reset =   ub_post_reset,
2472 };
2473
2474 static int __init ub_init(void)
2475 {
2476         int rc;
2477         int i;
2478
2479         for (i = 0; i < UB_QLOCK_NUM; i++)
2480                 spin_lock_init(&ub_qlockv[i]);
2481
2482         if ((rc = register_blkdev(UB_MAJOR, DRV_NAME)) != 0)
2483                 goto err_regblkdev;
2484
2485         if ((rc = usb_register(&ub_driver)) != 0)
2486                 goto err_register;
2487
2488         usb_usual_set_present(USB_US_TYPE_UB);
2489         return 0;
2490
2491 err_register:
2492         unregister_blkdev(UB_MAJOR, DRV_NAME);
2493 err_regblkdev:
2494         return rc;
2495 }
2496
2497 static void __exit ub_exit(void)
2498 {
2499         usb_deregister(&ub_driver);
2500
2501         unregister_blkdev(UB_MAJOR, DRV_NAME);
2502         usb_usual_clear_present(USB_US_TYPE_UB);
2503 }
2504
2505 module_init(ub_init);
2506 module_exit(ub_exit);
2507
2508 MODULE_LICENSE("GPL");