drivers/block/ub.c

   1 /*
   2  * The low performance USB storage driver (ub).
   3  *
   4  * Copyright (c) 1999, 2000 Matthew Dharm (mdharm-usb@one-eyed-alien.net)
   5  * Copyright (C) 2004 Pete Zaitcev (zaitcev@yahoo.com)
   6  *
   7  * This work is a part of Linux kernel, is derived from it,
   8  * and is not licensed separately. See file COPYING for details.
   9  *
  10  * TODO (sorted by decreasing priority)
  11  *  -- set readonly flag for CDs, set removable flag for CF readers
  12  *  -- do inquiry and verify we got a disk and not a tape (for LUN mismatch)
  13  *  -- verify the 13 conditions and do bulk resets
  14  *  -- highmem
  15  *  -- move top_sense and work_bcs into separate allocations (if they survive)
  16  *     for cache purists and esoteric architectures.
  17  *  -- Allocate structure for LUN 0 before the first ub_sync_tur, avoid NULL. ?
  18  *  -- prune comments, they are too volumnous
  19  *  -- Resove XXX's
  20  *  -- CLEAR, CLR2STS, CLRRS seem to be ripe for refactoring.
  21  */
  22 #include <linux/kernel.h>
  23 #include <linux/module.h>
  24 #include <linux/usb.h>
  25 #include <linux/usb_usual.h>
  26 #include <linux/blkdev.h>
  27 #include <linux/timer.h>
  28 #include <scsi/scsi.h>
  29
  30 #define DRV_NAME "ub"
  31
  32 #define UB_MAJOR 180
  33
  34 /*
  35  * The command state machine is the key model for understanding of this driver.
  36  *
  37  * The general rule is that all transitions are done towards the bottom
  38  * of the diagram, thus preventing any loops.
  39  *
  40  * An exception to that is how the STAT state is handled. A counter allows it
  41  * to be re-entered along the path marked with [C].
  42  *
  43  *       +--------+
  44  *       ! INIT   !
  45  *       +--------+
  46  *           !
  47  *        ub_scsi_cmd_start fails ->--------------------------------------\
  48  *           !                                                            !
  49  *           V                                                            !
  50  *       +--------+                                                       !
  51  *       ! CMD    !                                                       !
  52  *       +--------+                                                       !
  53  *           !                                            +--------+      !
  54  *         was -EPIPE -->-------------------------------->! CLEAR  !      !
  55  *           !                                            +--------+      !
  56  *           !                                                !           !
  57  *         was error -->------------------------------------- ! --------->\
  58  *           !                                                !           !
  59  *  /--<-- cmd->dir == NONE ?                                 !           !
  60  *  !        !                                                !           !
  61  *  !        V                                                !           !
  62  *  !    +--------+                                           !           !
  63  *  !    ! DATA   !                                           !           !
  64  *  !    +--------+                                           !           !
  65  *  !        !                           +---------+          !           !
  66  *  !      was -EPIPE -->--------------->! CLR2STS !          !           !
  67  *  !        !                           +---------+          !           !
  68  *  !        !                                !               !           !
  69  *  !        !                              was error -->---- ! --------->\
  70  *  !      was error -->--------------------- ! ------------- ! --------->\
  71  *  !        !                                !               !           !
  72  *  !        V                                !               !           !
  73  *  \--->+--------+                           !               !           !
  74  *       ! STAT   !<--------------------------/               !           !
  75  *  /--->+--------+                                           !           !
  76  *  !        !                                                !           !
  77  * [C]     was -EPIPE -->-----------\                         !           !
  78  *  !        !                      !                         !           !
  79  *  +<---- len == 0                 !                         !           !
  80  *  !        !                      !                         !           !
  81  *  !      was error -->--------------------------------------!---------->\
  82  *  !        !                      !                         !           !
  83  *  +<---- bad CSW                  !                         !           !
  84  *  +<---- bad tag                  !                         !           !
  85  *  !        !                      V                         !           !
  86  *  !        !                 +--------+                     !           !
  87  *  !        !                 ! CLRRS  !                     !           !
  88  *  !        !                 +--------+                     !           !
  89  *  !        !                      !                         !           !
  90  *  \------- ! --------------------[C]--------\               !           !
  91  *           !                                !               !           !
  92  *         cmd->error---\                +--------+           !           !
  93  *           !          +--------------->! SENSE  !<----------/           !
  94  *         STAT_FAIL----/                +--------+                       !
  95  *           !                                !                           V
  96  *           !                                V                      +--------+
  97  *           \--------------------------------\--------------------->! DONE   !
  98  *                                                                   +--------+
  99  */
 100
 101 /*
 102  * This many LUNs per USB device.
 103  * Every one of them takes a host, see UB_MAX_HOSTS.
 104  */
 105 #define UB_MAX_LUNS   9
 106
 107 /*
 108  */
 109
 110 #define UB_PARTS_PER_LUN      8
 111
 112 #define UB_MAX_CDB_SIZE      16         /* Corresponds to Bulk */
 113
 114 #define UB_SENSE_SIZE  18
 115
 116 /*
 117  */
 118
 119 /* command block wrapper */
 120 struct bulk_cb_wrap {
 121         __le32  Signature;              /* contains 'USBC' */
 122         u32     Tag;                    /* unique per command id */
 123         __le32  DataTransferLength;     /* size of data */
 124         u8      Flags;                  /* direction in bit 0 */
 125         u8      Lun;                    /* LUN */
 126         u8      Length;                 /* of of the CDB */
 127         u8      CDB[UB_MAX_CDB_SIZE];   /* max command */
 128 };
 129
 130 #define US_BULK_CB_WRAP_LEN     31
 131 #define US_BULK_CB_SIGN         0x43425355      /*spells out USBC */
 132 #define US_BULK_FLAG_IN         1
 133 #define US_BULK_FLAG_OUT        0
 134
 135 /* command status wrapper */
 136 struct bulk_cs_wrap {
 137         __le32  Signature;              /* should = 'USBS' */
 138         u32     Tag;                    /* same as original command */
 139         __le32  Residue;                /* amount not transferred */
 140         u8      Status;                 /* see below */
 141 };
 142
 143 #define US_BULK_CS_WRAP_LEN     13
 144 #define US_BULK_CS_SIGN         0x53425355      /* spells out 'USBS' */
 145 #define US_BULK_STAT_OK         0
 146 #define US_BULK_STAT_FAIL       1
 147 #define US_BULK_STAT_PHASE      2
 148
 149 /* bulk-only class specific requests */
 150 #define US_BULK_RESET_REQUEST   0xff
 151 #define US_BULK_GET_MAX_LUN     0xfe
 152
 153 /*
 154  */
 155 struct ub_dev;
 156
 157 #define UB_MAX_REQ_SG   9       /* cdrecord requires 32KB and maybe a header */
 158 #define UB_MAX_SECTORS 64
 159
 160 /*
 161  * A second is more than enough for a 32K transfer (UB_MAX_SECTORS)
 162  * even if a webcam hogs the bus, but some devices need time to spin up.
 163  */
 164 #define UB_URB_TIMEOUT  (HZ*2)
 165 #define UB_DATA_TIMEOUT (HZ*5)  /* ZIP does spin-ups in the data phase */
 166 #define UB_STAT_TIMEOUT (HZ*5)  /* Same spinups and eject for a dataless cmd. */
 167 #define UB_CTRL_TIMEOUT (HZ/2)  /* 500ms ought to be enough to clear a stall */
 168
 169 /*
 170  * An instance of a SCSI command in transit.
 171  */
 172 #define UB_DIR_NONE     0
 173 #define UB_DIR_READ     1
 174 #define UB_DIR_ILLEGAL2 2
 175 #define UB_DIR_WRITE    3
 176
 177 #define UB_DIR_CHAR(c)  (((c)==UB_DIR_WRITE)? 'w': \
 178                          (((c)==UB_DIR_READ)? 'r': 'n'))
 179
 180 enum ub_scsi_cmd_state {
 181         UB_CMDST_INIT,                  /* Initial state */
 182         UB_CMDST_CMD,                   /* Command submitted */
 183         UB_CMDST_DATA,                  /* Data phase */
 184         UB_CMDST_CLR2STS,               /* Clearing before requesting status */
 185         UB_CMDST_STAT,                  /* Status phase */
 186         UB_CMDST_CLEAR,                 /* Clearing a stall (halt, actually) */
 187         UB_CMDST_CLRRS,                 /* Clearing before retrying status */
 188         UB_CMDST_SENSE,                 /* Sending Request Sense */
 189         UB_CMDST_DONE                   /* Final state */
 190 };
 191
 192 struct ub_scsi_cmd {
 193         unsigned char cdb[UB_MAX_CDB_SIZE];
 194         unsigned char cdb_len;
 195
 196         unsigned char dir;              /* 0 - none, 1 - read, 3 - write. */
 197         enum ub_scsi_cmd_state state;
 198         unsigned int tag;
 199         struct ub_scsi_cmd *next;
 200
 201         int error;                      /* Return code - valid upon done */
 202         unsigned int act_len;           /* Return size */
 203         unsigned char key, asc, ascq;   /* May be valid if error==-EIO */
 204
 205         int stat_count;                 /* Retries getting status. */
 206
 207         unsigned int len;               /* Requested length */
 208         unsigned int current_sg;
 209         unsigned int nsg;               /* sgv[nsg] */
 210         struct scatterlist sgv[UB_MAX_REQ_SG];
 211
 212         struct ub_lun *lun;
 213         void (*done)(struct ub_dev *, struct ub_scsi_cmd *);
 214         void *back;
 215 };
 216
 217 struct ub_request {
 218         struct request *rq;
 219         unsigned int current_try;
 220         unsigned int nsg;               /* sgv[nsg] */
 221         struct scatterlist sgv[UB_MAX_REQ_SG];
 222 };
 223
 224 /*
 225  */
 226 struct ub_capacity {
 227         unsigned long nsec;             /* Linux size - 512 byte sectors */
 228         unsigned int bsize;             /* Linux hardsect_size */
 229         unsigned int bshift;            /* Shift between 512 and hard sects */
 230 };
 231
 232 /*
 233  * This is a direct take-off from linux/include/completion.h
 234  * The difference is that I do not wait on this thing, just poll.
 235  * When I want to wait (ub_probe), I just use the stock completion.
 236  *
 237  * Note that INIT_COMPLETION takes no lock. It is correct. But why
 238  * in the bloody hell that thing takes struct instead of pointer to struct
 239  * is quite beyond me. I just copied it from the stock completion.
 240  */
 241 struct ub_completion {
 242         unsigned int done;
 243         spinlock_t lock;
 244 };
 245
 246 static inline void ub_init_completion(struct ub_completion *x)
 247 {
 248         x->done = 0;
 249         spin_lock_init(&x->lock);
 250 }
 251
 252 #define UB_INIT_COMPLETION(x)   ((x).done = 0)
 253
 254 static void ub_complete(struct ub_completion *x)
 255 {
 256         unsigned long flags;
 257
 258         spin_lock_irqsave(&x->lock, flags);
 259         x->done++;
 260         spin_unlock_irqrestore(&x->lock, flags);
 261 }
 262
 263 static int ub_is_completed(struct ub_completion *x)
 264 {
 265         unsigned long flags;
 266         int ret;
 267
 268         spin_lock_irqsave(&x->lock, flags);
 269         ret = x->done;
 270         spin_unlock_irqrestore(&x->lock, flags);
 271         return ret;
 272 }
 273
 274 /*
 275  */
 276 struct ub_scsi_cmd_queue {
 277         int qlen, qmax;
 278         struct ub_scsi_cmd *head, *tail;
 279 };
 280
 281 /*
 282  * The block device instance (one per LUN).
 283  */
 284 struct ub_lun {
 285         struct ub_dev *udev;
 286         struct list_head link;
 287         struct gendisk *disk;
 288         int id;                         /* Host index */
 289         int num;                        /* LUN number */
 290         char name[16];
 291
 292         int changed;                    /* Media was changed */
 293         int removable;
 294         int readonly;
 295
 296         struct ub_request urq;
 297
 298         /* Use Ingo's mempool if or when we have more than one command. */
 299         /*
 300          * Currently we never need more than one command for the whole device.
 301          * However, giving every LUN a command is a cheap and automatic way
 302          * to enforce fairness between them.
 303          */
 304         int cmda[1];
 305         struct ub_scsi_cmd cmdv[1];
 306
 307         struct ub_capacity capacity;
 308 };
 309
 310 /*
 311  * The USB device instance.
 312  */
 313 struct ub_dev {
 314         spinlock_t *lock;
 315         atomic_t poison;                /* The USB device is disconnected */
 316         int openc;                      /* protected by ub_lock! */
 317                                         /* kref is too implicit for our taste */
 318         int reset;                      /* Reset is running */
 319         unsigned int tagcnt;
 320         char name[12];
 321         struct usb_device *dev;
 322         struct usb_interface *intf;
 323
 324         struct list_head luns;
 325
 326         unsigned int send_bulk_pipe;    /* cached pipe values */
 327         unsigned int recv_bulk_pipe;
 328         unsigned int send_ctrl_pipe;
 329         unsigned int recv_ctrl_pipe;
 330
 331         struct tasklet_struct tasklet;
 332
 333         struct ub_scsi_cmd_queue cmd_queue;
 334         struct ub_scsi_cmd top_rqs_cmd; /* REQUEST SENSE */
 335         unsigned char top_sense[UB_SENSE_SIZE];
 336
 337         struct ub_completion work_done;
 338         struct urb work_urb;
 339         struct timer_list work_timer;
 340         int last_pipe;                  /* What might need clearing */
 341         __le32 signature;               /* Learned signature */
 342         struct bulk_cb_wrap work_bcb;
 343         struct bulk_cs_wrap work_bcs;
 344         struct usb_ctrlrequest work_cr;
 345
 346         struct work_struct reset_work;
 347         wait_queue_head_t reset_wait;
 348
 349         int sg_stat[6];
 350 };
 351
 352 /*
 353  */
 354 static void ub_cleanup(struct ub_dev *sc);
 355 static int ub_request_fn_1(struct ub_lun *lun, struct request *rq);
 356 static void ub_cmd_build_block(struct ub_dev *sc, struct ub_lun *lun,
 357     struct ub_scsi_cmd *cmd, struct ub_request *urq);
 358 static void ub_cmd_build_packet(struct ub_dev *sc, struct ub_lun *lun,
 359     struct ub_scsi_cmd *cmd, struct ub_request *urq);
 360 static void ub_rw_cmd_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 361 static void ub_end_rq(struct request *rq, unsigned int status);
 362 static int ub_rw_cmd_retry(struct ub_dev *sc, struct ub_lun *lun,
 363     struct ub_request *urq, struct ub_scsi_cmd *cmd);
 364 static int ub_submit_scsi(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 365 static void ub_urb_complete(struct urb *urb, struct pt_regs *pt);
 366 static void ub_scsi_action(unsigned long _dev);
 367 static void ub_scsi_dispatch(struct ub_dev *sc);
 368 static void ub_scsi_urb_compl(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 369 static void ub_data_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 370 static void ub_state_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd, int rc);
 371 static int __ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 372 static void ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 373 static void ub_state_stat_counted(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 374 static void ub_state_sense(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 375 static int ub_submit_clear_stall(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
 376     int stalled_pipe);
 377 static void ub_top_sense_done(struct ub_dev *sc, struct ub_scsi_cmd *scmd);
 378 static void ub_reset_enter(struct ub_dev *sc, int try);
 379 static void ub_reset_task(void *arg);
 380 static int ub_sync_tur(struct ub_dev *sc, struct ub_lun *lun);
 381 static int ub_sync_read_cap(struct ub_dev *sc, struct ub_lun *lun,
 382     struct ub_capacity *ret);
 383 static int ub_sync_reset(struct ub_dev *sc);
 384 static int ub_probe_clear_stall(struct ub_dev *sc, int stalled_pipe);
 385 static int ub_probe_lun(struct ub_dev *sc, int lnum);
 386
 387 /*
 388  */
 389 #ifdef CONFIG_USB_LIBUSUAL
 390
 391 #define ub_usb_ids  storage_usb_ids
 392 #else
 393
 394 static struct usb_device_id ub_usb_ids[] = {
 395         { USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, US_SC_SCSI, US_PR_BULK) },
 396         { }
 397 };
 398
 399 MODULE_DEVICE_TABLE(usb, ub_usb_ids);
 400 #endif /* CONFIG_USB_LIBUSUAL */
 401
 402 /*
 403  * Find me a way to identify "next free minor" for add_disk(),
 404  * and the array disappears the next day. However, the number of
 405  * hosts has something to do with the naming and /proc/partitions.
 406  * This has to be thought out in detail before changing.
 407  * If UB_MAX_HOST was 1000, we'd use a bitmap. Or a better data structure.
 408  */
 409 #define UB_MAX_HOSTS  26
 410 static char ub_hostv[UB_MAX_HOSTS];
 411
 412 #define UB_QLOCK_NUM 5
 413 static spinlock_t ub_qlockv[UB_QLOCK_NUM];
 414 static int ub_qlock_next = 0;
 415
 416 static DEFINE_SPINLOCK(ub_lock);        /* Locks globals and ->openc */
 417
 418 /*
 419  * The id allocator.
 420  *
 421  * This also stores the host for indexing by minor, which is somewhat dirty.
 422  */
 423 static int ub_id_get(void)
 424 {
 425         unsigned long flags;
 426         int i;
 427
 428         spin_lock_irqsave(&ub_lock, flags);
 429         for (i = 0; i < UB_MAX_HOSTS; i++) {
 430                 if (ub_hostv[i] == 0) {
 431                         ub_hostv[i] = 1;
 432                         spin_unlock_irqrestore(&ub_lock, flags);
 433                         return i;
 434                 }
 435         }
 436         spin_unlock_irqrestore(&ub_lock, flags);
 437         return -1;
 438 }
 439
 440 static void ub_id_put(int id)
 441 {
 442         unsigned long flags;
 443
 444         if (id < 0 || id >= UB_MAX_HOSTS) {
 445                 printk(KERN_ERR DRV_NAME ": bad host ID %d\n", id);
 446                 return;
 447         }
 448
 449         spin_lock_irqsave(&ub_lock, flags);
 450         if (ub_hostv[id] == 0) {
 451                 spin_unlock_irqrestore(&ub_lock, flags);
 452                 printk(KERN_ERR DRV_NAME ": freeing free host ID %d\n", id);
 453                 return;
 454         }
 455         ub_hostv[id] = 0;
 456         spin_unlock_irqrestore(&ub_lock, flags);
 457 }
 458
 459 /*
 460  * This is necessitated by the fact that blk_cleanup_queue does not
 461  * necesserily destroy the queue. Instead, it may merely decrease q->refcnt.
 462  * Since our blk_init_queue() passes a spinlock common with ub_dev,
 463  * we have life time issues when ub_cleanup frees ub_dev.
 464  */
 465 static spinlock_t *ub_next_lock(void)
 466 {
 467         unsigned long flags;
 468         spinlock_t *ret;
 469
 470         spin_lock_irqsave(&ub_lock, flags);
 471         ret = &ub_qlockv[ub_qlock_next];
 472         ub_qlock_next = (ub_qlock_next + 1) % UB_QLOCK_NUM;
 473         spin_unlock_irqrestore(&ub_lock, flags);
 474         return ret;
 475 }
 476
 477 /*
 478  * Downcount for deallocation. This rides on two assumptions:
 479  *  - once something is poisoned, its refcount cannot grow
 480  *  - opens cannot happen at this time (del_gendisk was done)
 481  * If the above is true, we can drop the lock, which we need for
 482  * blk_cleanup_queue(): the silly thing may attempt to sleep.
 483  * [Actually, it never needs to sleep for us, but it calls might_sleep()]
 484  */
 485 static void ub_put(struct ub_dev *sc)
 486 {
 487         unsigned long flags;
 488
 489         spin_lock_irqsave(&ub_lock, flags);
 490         --sc->openc;
 491         if (sc->openc == 0 && atomic_read(&sc->poison)) {
 492                 spin_unlock_irqrestore(&ub_lock, flags);
 493                 ub_cleanup(sc);
 494         } else {
 495                 spin_unlock_irqrestore(&ub_lock, flags);
 496         }
 497 }
 498
 499 /*
 500  * Final cleanup and deallocation.
 501  */
 502 static void ub_cleanup(struct ub_dev *sc)
 503 {
 504         struct list_head *p;
 505         struct ub_lun *lun;
 506         request_queue_t *q;
 507
 508         while (!list_empty(&sc->luns)) {
 509                 p = sc->luns.next;
 510                 lun = list_entry(p, struct ub_lun, link);
 511                 list_del(p);
 512
 513                 /* I don't think queue can be NULL. But... Stolen from sx8.c */
 514                 if ((q = lun->disk->queue) != NULL)
 515                         blk_cleanup_queue(q);
 516                 /*
 517                  * If we zero disk->private_data BEFORE put_disk, we have
 518                  * to check for NULL all over the place in open, release,
 519                  * check_media and revalidate, because the block level
 520                  * semaphore is well inside the put_disk.
 521                  * But we cannot zero after the call, because *disk is gone.
 522                  * The sd.c is blatantly racy in this area.
 523                  */
 524                 /* disk->private_data = NULL; */
 525                 put_disk(lun->disk);
 526                 lun->disk = NULL;
 527
 528                 ub_id_put(lun->id);
 529                 kfree(lun);
 530         }
 531
 532         usb_set_intfdata(sc->intf, NULL);
 533         usb_put_intf(sc->intf);
 534         usb_put_dev(sc->dev);
 535         kfree(sc);
 536 }
 537
 538 /*
 539  * The "command allocator".
 540  */
 541 static struct ub_scsi_cmd *ub_get_cmd(struct ub_lun *lun)
 542 {
 543         struct ub_scsi_cmd *ret;
 544
 545         if (lun->cmda[0])
 546                 return NULL;
 547         ret = &lun->cmdv[0];
 548         lun->cmda[0] = 1;
 549         return ret;
 550 }
 551
 552 static void ub_put_cmd(struct ub_lun *lun, struct ub_scsi_cmd *cmd)
 553 {
 554         if (cmd != &lun->cmdv[0]) {
 555                 printk(KERN_WARNING "%s: releasing a foreign cmd %p\n",
 556                     lun->name, cmd);
 557                 return;
 558         }
 559         if (!lun->cmda[0]) {
 560                 printk(KERN_WARNING "%s: releasing a free cmd\n", lun->name);
 561                 return;
 562         }
 563         lun->cmda[0] = 0;
 564 }
 565
 566 /*
 567  * The command queue.
 568  */
 569 static void ub_cmdq_add(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 570 {
 571         struct ub_scsi_cmd_queue *t = &sc->cmd_queue;
 572
 573         if (t->qlen++ == 0) {
 574                 t->head = cmd;
 575                 t->tail = cmd;
 576         } else {
 577                 t->tail->next = cmd;
 578                 t->tail = cmd;
 579         }
 580
 581         if (t->qlen > t->qmax)
 582                 t->qmax = t->qlen;
 583 }
 584
 585 static void ub_cmdq_insert(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 586 {
 587         struct ub_scsi_cmd_queue *t = &sc->cmd_queue;
 588
 589         if (t->qlen++ == 0) {
 590                 t->head = cmd;
 591                 t->tail = cmd;
 592         } else {
 593                 cmd->next = t->head;
 594                 t->head = cmd;
 595         }
 596
 597         if (t->qlen > t->qmax)
 598                 t->qmax = t->qlen;
 599 }
 600
 601 static struct ub_scsi_cmd *ub_cmdq_pop(struct ub_dev *sc)
 602 {
 603         struct ub_scsi_cmd_queue *t = &sc->cmd_queue;
 604         struct ub_scsi_cmd *cmd;
 605
 606         if (t->qlen == 0)
 607                 return NULL;
 608         if (--t->qlen == 0)
 609                 t->tail = NULL;
 610         cmd = t->head;
 611         t->head = cmd->next;
 612         cmd->next = NULL;
 613         return cmd;
 614 }
 615
 616 #define ub_cmdq_peek(sc)  ((sc)->cmd_queue.head)
 617
 618 /*
 619  * The request function is our main entry point
 620  */
 621
 622 static void ub_request_fn(request_queue_t *q)
 623 {
 624         struct ub_lun *lun = q->queuedata;
 625         struct request *rq;
 626
 627         while ((rq = elv_next_request(q)) != NULL) {
 628                 if (ub_request_fn_1(lun, rq) != 0) {
 629                         blk_stop_queue(q);
 630                         break;
 631                 }
 632         }
 633 }
 634
 635 static int ub_request_fn_1(struct ub_lun *lun, struct request *rq)
 636 {
 637         struct ub_dev *sc = lun->udev;
 638         struct ub_scsi_cmd *cmd;
 639         struct ub_request *urq;
 640         int n_elem;
 641
 642         if (atomic_read(&sc->poison)) {
 643                 blkdev_dequeue_request(rq);
 644                 ub_end_rq(rq, DID_NO_CONNECT << 16);
 645                 return 0;
 646         }
 647
 648         if (lun->changed && !blk_pc_request(rq)) {
 649                 blkdev_dequeue_request(rq);
 650                 ub_end_rq(rq, SAM_STAT_CHECK_CONDITION);
 651                 return 0;
 652         }
 653
 654         if (lun->urq.rq != NULL)
 655                 return -1;
 656         if ((cmd = ub_get_cmd(lun)) == NULL)
 657                 return -1;
 658         memset(cmd, 0, sizeof(struct ub_scsi_cmd));
 659
 660         blkdev_dequeue_request(rq);
 661
 662         urq = &lun->urq;
 663         memset(urq, 0, sizeof(struct ub_request));
 664         urq->rq = rq;
 665
 666         /*
 667          * get scatterlist from block layer
 668          */
 669         n_elem = blk_rq_map_sg(lun->disk->queue, rq, &urq->sgv[0]);
 670         if (n_elem < 0) {
 671                 /* Impossible, because blk_rq_map_sg should not hit ENOMEM. */
 672                 printk(KERN_INFO "%s: failed request map (%d)\n",
 673                     lun->name, n_elem);
 674                 goto drop;
 675         }
 676         if (n_elem > UB_MAX_REQ_SG) {   /* Paranoia */
 677                 printk(KERN_WARNING "%s: request with %d segments\n",
 678                     lun->name, n_elem);
 679                 goto drop;
 680         }
 681         urq->nsg = n_elem;
 682         sc->sg_stat[n_elem < 5 ? n_elem : 5]++;
 683
 684         if (blk_pc_request(rq)) {
 685                 ub_cmd_build_packet(sc, lun, cmd, urq);
 686         } else {
 687                 ub_cmd_build_block(sc, lun, cmd, urq);
 688         }
 689         cmd->state = UB_CMDST_INIT;
 690         cmd->lun = lun;
 691         cmd->done = ub_rw_cmd_done;
 692         cmd->back = urq;
 693
 694         cmd->tag = sc->tagcnt++;
 695         if (ub_submit_scsi(sc, cmd) != 0)
 696                 goto drop;
 697
 698         return 0;
 699
 700 drop:
 701         ub_put_cmd(lun, cmd);
 702         ub_end_rq(rq, DID_ERROR << 16);
 703         return 0;
 704 }
 705
 706 static void ub_cmd_build_block(struct ub_dev *sc, struct ub_lun *lun,
 707     struct ub_scsi_cmd *cmd, struct ub_request *urq)
 708 {
 709         struct request *rq = urq->rq;
 710         unsigned int block, nblks;
 711
 712         if (rq_data_dir(rq) == WRITE)
 713                 cmd->dir = UB_DIR_WRITE;
 714         else
 715                 cmd->dir = UB_DIR_READ;
 716
 717         cmd->nsg = urq->nsg;
 718         memcpy(cmd->sgv, urq->sgv, sizeof(struct scatterlist) * cmd->nsg);
 719
 720         /*
 721          * build the command
 722          *
 723          * The call to blk_queue_hardsect_size() guarantees that request
 724          * is aligned, but it is given in terms of 512 byte units, always.
 725          */
 726         block = rq->sector >> lun->capacity.bshift;
 727         nblks = rq->nr_sectors >> lun->capacity.bshift;
 728
 729         cmd->cdb[0] = (cmd->dir == UB_DIR_READ)? READ_10: WRITE_10;
 730         /* 10-byte uses 4 bytes of LBA: 2147483648KB, 2097152MB, 2048GB */
 731         cmd->cdb[2] = block >> 24;
 732         cmd->cdb[3] = block >> 16;
 733         cmd->cdb[4] = block >> 8;
 734         cmd->cdb[5] = block;
 735         cmd->cdb[7] = nblks >> 8;
 736         cmd->cdb[8] = nblks;
 737         cmd->cdb_len = 10;
 738
 739         cmd->len = rq->nr_sectors * 512;
 740 }
 741
 742 static void ub_cmd_build_packet(struct ub_dev *sc, struct ub_lun *lun,
 743     struct ub_scsi_cmd *cmd, struct ub_request *urq)
 744 {
 745         struct request *rq = urq->rq;
 746
 747         if (rq->data_len == 0) {
 748                 cmd->dir = UB_DIR_NONE;
 749         } else {
 750                 if (rq_data_dir(rq) == WRITE)
 751                         cmd->dir = UB_DIR_WRITE;
 752                 else
 753                         cmd->dir = UB_DIR_READ;
 754         }
 755
 756         cmd->nsg = urq->nsg;
 757         memcpy(cmd->sgv, urq->sgv, sizeof(struct scatterlist) * cmd->nsg);
 758
 759         memcpy(&cmd->cdb, rq->cmd, rq->cmd_len);
 760         cmd->cdb_len = rq->cmd_len;
 761
 762         cmd->len = rq->data_len;
 763 }
 764
 765 static void ub_rw_cmd_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 766 {
 767         struct ub_lun *lun = cmd->lun;
 768         struct ub_request *urq = cmd->back;
 769         struct request *rq;
 770         unsigned int scsi_status;
 771
 772         rq = urq->rq;
 773
 774         if (cmd->error == 0) {
 775                 if (blk_pc_request(rq)) {
 776                         if (cmd->act_len >= rq->data_len)
 777                                 rq->data_len = 0;
 778                         else
 779                                 rq->data_len -= cmd->act_len;
 780                 }
 781                 scsi_status = 0;
 782         } else {
 783                 if (blk_pc_request(rq)) {
 784                         /* UB_SENSE_SIZE is smaller than SCSI_SENSE_BUFFERSIZE */
 785                         memcpy(rq->sense, sc->top_sense, UB_SENSE_SIZE);
 786                         rq->sense_len = UB_SENSE_SIZE;
 787                         if (sc->top_sense[0] != 0)
 788                                 scsi_status = SAM_STAT_CHECK_CONDITION;
 789                         else
 790                                 scsi_status = DID_ERROR << 16;
 791                 } else {
 792                         if (cmd->error == -EIO) {
 793                                 if (ub_rw_cmd_retry(sc, lun, urq, cmd) == 0)
 794                                         return;
 795                         }
 796                         scsi_status = SAM_STAT_CHECK_CONDITION;
 797                 }
 798         }
 799
 800         urq->rq = NULL;
 801
 802         ub_put_cmd(lun, cmd);
 803         ub_end_rq(rq, scsi_status);
 804         blk_start_queue(lun->disk->queue);
 805 }
 806
 807 static void ub_end_rq(struct request *rq, unsigned int scsi_status)
 808 {
 809         int uptodate;
 810
 811         if (scsi_status == 0) {
 812                 uptodate = 1;
 813         } else {
 814                 uptodate = 0;
 815                 rq->errors = scsi_status;
 816         }
 817         end_that_request_first(rq, uptodate, rq->hard_nr_sectors);
 818         end_that_request_last(rq, uptodate);
 819 }
 820
 821 static int ub_rw_cmd_retry(struct ub_dev *sc, struct ub_lun *lun,
 822     struct ub_request *urq, struct ub_scsi_cmd *cmd)
 823 {
 824
 825         if (atomic_read(&sc->poison))
 826                 return -ENXIO;
 827
 828         ub_reset_enter(sc, urq->current_try);
 829
 830         if (urq->current_try >= 3)
 831                 return -EIO;
 832         urq->current_try++;
 833
 834         /* Remove this if anyone complains of flooding. */
 835         printk(KERN_DEBUG "%s: dir %c len/act %d/%d "
 836             "[sense %x %02x %02x] retry %d\n",
 837             sc->name, UB_DIR_CHAR(cmd->dir), cmd->len, cmd->act_len,
 838             cmd->key, cmd->asc, cmd->ascq, urq->current_try);
 839
 840         memset(cmd, 0, sizeof(struct ub_scsi_cmd));
 841         ub_cmd_build_block(sc, lun, cmd, urq);
 842
 843         cmd->state = UB_CMDST_INIT;
 844         cmd->lun = lun;
 845         cmd->done = ub_rw_cmd_done;
 846         cmd->back = urq;
 847
 848         cmd->tag = sc->tagcnt++;
 849
 850 #if 0 /* Wasteful */
 851         return ub_submit_scsi(sc, cmd);
 852 #else
 853         ub_cmdq_add(sc, cmd);
 854         return 0;
 855 #endif
 856 }
 857
 858 /*
 859  * Submit a regular SCSI operation (not an auto-sense).
 860  *
 861  * The Iron Law of Good Submit Routine is:
 862  * Zero return - callback is done, Nonzero return - callback is not done.
 863  * No exceptions.
 864  *
 865  * Host is assumed locked.
 866  */
 867 static int ub_submit_scsi(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 868 {
 869
 870         if (cmd->state != UB_CMDST_INIT ||
 871             (cmd->dir != UB_DIR_NONE && cmd->len == 0)) {
 872                 return -EINVAL;
 873         }
 874
 875         ub_cmdq_add(sc, cmd);
 876         /*
 877          * We can call ub_scsi_dispatch(sc) right away here, but it's a little
 878          * safer to jump to a tasklet, in case upper layers do something silly.
 879          */
 880         tasklet_schedule(&sc->tasklet);
 881         return 0;
 882 }
 883
 884 /*
 885  * Submit the first URB for the queued command.
 886  * This function does not deal with queueing in any way.
 887  */
 888 static int ub_scsi_cmd_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 889 {
 890         struct bulk_cb_wrap *bcb;
 891         int rc;
 892
 893         bcb = &sc->work_bcb;
 894
 895         /*
 896          * ``If the allocation length is eighteen or greater, and a device
 897          * server returns less than eithteen bytes of data, the application
 898          * client should assume that the bytes not transferred would have been
 899          * zeroes had the device server returned those bytes.''
 900          *
 901          * We zero sense for all commands so that when a packet request
 902          * fails it does not return a stale sense.
 903          */
 904         memset(&sc->top_sense, 0, UB_SENSE_SIZE);
 905
 906         /* set up the command wrapper */
 907         bcb->Signature = cpu_to_le32(US_BULK_CB_SIGN);
 908         bcb->Tag = cmd->tag;            /* Endianness is not important */
 909         bcb->DataTransferLength = cpu_to_le32(cmd->len);
 910         bcb->Flags = (cmd->dir == UB_DIR_READ) ? 0x80 : 0;
 911         bcb->Lun = (cmd->lun != NULL) ? cmd->lun->num : 0;
 912         bcb->Length = cmd->cdb_len;
 913
 914         /* copy the command payload */
 915         memcpy(bcb->CDB, cmd->cdb, UB_MAX_CDB_SIZE);
 916
 917         UB_INIT_COMPLETION(sc->work_done);
 918
 919         sc->last_pipe = sc->send_bulk_pipe;
 920         usb_fill_bulk_urb(&sc->work_urb, sc->dev, sc->send_bulk_pipe,
 921             bcb, US_BULK_CB_WRAP_LEN, ub_urb_complete, sc);
 922
 923         /* Fill what we shouldn't be filling, because usb-storage did so. */
 924         sc->work_urb.actual_length = 0;
 925         sc->work_urb.error_count = 0;
 926         sc->work_urb.status = 0;
 927
 928         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
 929                 /* XXX Clear stalls */
 930                 ub_complete(&sc->work_done);
 931                 return rc;
 932         }
 933
 934         sc->work_timer.expires = jiffies + UB_URB_TIMEOUT;
 935         add_timer(&sc->work_timer);
 936
 937         cmd->state = UB_CMDST_CMD;
 938         return 0;
 939 }
 940
 941 /*
 942  * Timeout handler.
 943  */
 944 static void ub_urb_timeout(unsigned long arg)
 945 {
 946         struct ub_dev *sc = (struct ub_dev *) arg;
 947         unsigned long flags;
 948
 949         spin_lock_irqsave(sc->lock, flags);
 950         if (!ub_is_completed(&sc->work_done))
 951                 usb_unlink_urb(&sc->work_urb);
 952         spin_unlock_irqrestore(sc->lock, flags);
 953 }
 954
 955 /*
 956  * Completion routine for the work URB.
 957  *
 958  * This can be called directly from usb_submit_urb (while we have
 959  * the sc->lock taken) and from an interrupt (while we do NOT have
 960  * the sc->lock taken). Therefore, bounce this off to a tasklet.
 961  */
 962 static void ub_urb_complete(struct urb *urb, struct pt_regs *pt)
 963 {
 964         struct ub_dev *sc = urb->context;
 965
 966         ub_complete(&sc->work_done);
 967         tasklet_schedule(&sc->tasklet);
 968 }
 969
 970 static void ub_scsi_action(unsigned long _dev)
 971 {
 972         struct ub_dev *sc = (struct ub_dev *) _dev;
 973         unsigned long flags;
 974
 975         spin_lock_irqsave(sc->lock, flags);
 976         ub_scsi_dispatch(sc);
 977         spin_unlock_irqrestore(sc->lock, flags);
 978 }
 979
 980 static void ub_scsi_dispatch(struct ub_dev *sc)
 981 {
 982         struct ub_scsi_cmd *cmd;
 983         int rc;
 984
 985         while (!sc->reset && (cmd = ub_cmdq_peek(sc)) != NULL) {
 986                 if (cmd->state == UB_CMDST_DONE) {
 987                         ub_cmdq_pop(sc);
 988                         (*cmd->done)(sc, cmd);
 989                 } else if (cmd->state == UB_CMDST_INIT) {
 990                         if ((rc = ub_scsi_cmd_start(sc, cmd)) == 0)
 991                                 break;
 992                         cmd->error = rc;
 993                         cmd->state = UB_CMDST_DONE;
 994                 } else {
 995                         if (!ub_is_completed(&sc->work_done))
 996                                 break;
 997                         del_timer(&sc->work_timer);
 998                         ub_scsi_urb_compl(sc, cmd);
 999                 }
1000         }
1001 }
1002
1003 static void ub_scsi_urb_compl(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1004 {
1005         struct urb *urb = &sc->work_urb;
1006         struct bulk_cs_wrap *bcs;
1007         int len;
1008         int rc;
1009
1010         if (atomic_read(&sc->poison)) {
1011                 ub_state_done(sc, cmd, -ENODEV);
1012                 return;
1013         }
1014
1015         if (cmd->state == UB_CMDST_CLEAR) {
1016                 if (urb->status == -EPIPE) {
1017                         /*
1018                          * STALL while clearning STALL.
1019                          * The control pipe clears itself - nothing to do.
1020                          */
1021                         printk(KERN_NOTICE "%s: stall on control pipe\n",
1022                             sc->name);
1023                         goto Bad_End;
1024                 }
1025
1026                 /*
1027                  * We ignore the result for the halt clear.
1028                  */
1029
1030                 /* reset the endpoint toggle */
1031                 usb_settoggle(sc->dev, usb_pipeendpoint(sc->last_pipe),
1032                         usb_pipeout(sc->last_pipe), 0);
1033
1034                 ub_state_sense(sc, cmd);
1035
1036         } else if (cmd->state == UB_CMDST_CLR2STS) {
1037                 if (urb->status == -EPIPE) {
1038                         printk(KERN_NOTICE "%s: stall on control pipe\n",
1039                             sc->name);
1040                         goto Bad_End;
1041                 }
1042
1043                 /*
1044                  * We ignore the result for the halt clear.
1045                  */
1046
1047                 /* reset the endpoint toggle */
1048                 usb_settoggle(sc->dev, usb_pipeendpoint(sc->last_pipe),
1049                         usb_pipeout(sc->last_pipe), 0);
1050
1051                 ub_state_stat(sc, cmd);
1052
1053         } else if (cmd->state == UB_CMDST_CLRRS) {
1054                 if (urb->status == -EPIPE) {
1055                         printk(KERN_NOTICE "%s: stall on control pipe\n",
1056                             sc->name);
1057                         goto Bad_End;
1058                 }
1059
1060                 /*
1061                  * We ignore the result for the halt clear.
1062                  */
1063
1064                 /* reset the endpoint toggle */
1065                 usb_settoggle(sc->dev, usb_pipeendpoint(sc->last_pipe),
1066                         usb_pipeout(sc->last_pipe), 0);
1067
1068                 ub_state_stat_counted(sc, cmd);
1069
1070         } else if (cmd->state == UB_CMDST_CMD) {
1071                 switch (urb->status) {
1072                 case 0:
1073                         break;
1074                 case -EOVERFLOW:
1075                         goto Bad_End;
1076                 case -EPIPE:
1077                         rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
1078                         if (rc != 0) {
1079                                 printk(KERN_NOTICE "%s: "
1080                                     "unable to submit clear (%d)\n",
1081                                     sc->name, rc);
1082                                 /*
1083                                  * This is typically ENOMEM or some other such shit.
1084                                  * Retrying is pointless. Just do Bad End on it...
1085                                  */
1086                                 ub_state_done(sc, cmd, rc);
1087                                 return;
1088                         }
1089                         cmd->state = UB_CMDST_CLEAR;
1090                         return;
1091                 case -ESHUTDOWN:        /* unplug */
1092                 case -EILSEQ:           /* unplug timeout on uhci */
1093                         ub_state_done(sc, cmd, -ENODEV);
1094                         return;
1095                 default:
1096                         goto Bad_End;
1097                 }
1098                 if (urb->actual_length != US_BULK_CB_WRAP_LEN) {
1099                         goto Bad_End;
1100                 }
1101
1102                 if (cmd->dir == UB_DIR_NONE || cmd->nsg < 1) {
1103                         ub_state_stat(sc, cmd);
1104                         return;
1105                 }
1106
1107                 // udelay(125);         // usb-storage has this
1108                 ub_data_start(sc, cmd);
1109
1110         } else if (cmd->state == UB_CMDST_DATA) {
1111                 if (urb->status == -EPIPE) {
1112                         rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
1113                         if (rc != 0) {
1114                                 printk(KERN_NOTICE "%s: "
1115                                     "unable to submit clear (%d)\n",
1116                                     sc->name, rc);
1117                                 ub_state_done(sc, cmd, rc);
1118                                 return;
1119                         }
1120                         cmd->state = UB_CMDST_CLR2STS;
1121                         return;
1122                 }
1123                 if (urb->status == -EOVERFLOW) {
1124                         /*
1125                          * A babble? Failure, but we must transfer CSW now.
1126                          */
1127                         cmd->error = -EOVERFLOW;        /* A cheap trick... */
1128                         ub_state_stat(sc, cmd);
1129                         return;
1130                 }
1131
1132                 if (cmd->dir == UB_DIR_WRITE) {
1133                         /*
1134                          * Do not continue writes in case of a failure.
1135                          * Doing so would cause sectors to be mixed up,
1136                          * which is worse than sectors lost.
1137                          *
1138                          * We must try to read the CSW, or many devices
1139                          * get confused.
1140                          */
1141                         len = urb->actual_length;
1142                         if (urb->status != 0 ||
1143                             len != cmd->sgv[cmd->current_sg].length) {
1144                                 cmd->act_len += len;
1145
1146                                 cmd->error = -EIO;
1147                                 ub_state_stat(sc, cmd);
1148                                 return;
1149                         }
1150
1151                 } else {
1152                         /*
1153                          * If an error occurs on read, we record it, and
1154                          * continue to fetch data in order to avoid bubble.
1155                          *
1156                          * As a small shortcut, we stop if we detect that
1157                          * a CSW mixed into data.
1158                          */
1159                         if (urb->status != 0)
1160                                 cmd->error = -EIO;
1161
1162                         len = urb->actual_length;
1163                         if (urb->status != 0 ||
1164                             len != cmd->sgv[cmd->current_sg].length) {
1165                                 if ((len & 0x1FF) == US_BULK_CS_WRAP_LEN)
1166                                         goto Bad_End;
1167                         }
1168                 }
1169
1170                 cmd->act_len += urb->actual_length;
1171
1172                 if (++cmd->current_sg < cmd->nsg) {
1173                         ub_data_start(sc, cmd);
1174                         return;
1175                 }
1176                 ub_state_stat(sc, cmd);
1177
1178         } else if (cmd->state == UB_CMDST_STAT) {
1179                 if (urb->status == -EPIPE) {
1180                         rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
1181                         if (rc != 0) {
1182                                 printk(KERN_NOTICE "%s: "
1183                                     "unable to submit clear (%d)\n",
1184                                     sc->name, rc);
1185                                 ub_state_done(sc, cmd, rc);
1186                                 return;
1187                         }
1188
1189                         /*
1190                          * Having a stall when getting CSW is an error, so
1191                          * make sure uppper levels are not oblivious to it.
1192                          */
1193                         cmd->error = -EIO;              /* A cheap trick... */
1194
1195                         cmd->state = UB_CMDST_CLRRS;
1196                         return;
1197                 }
1198
1199                 /* Catch everything, including -EOVERFLOW and other nasties. */
1200                 if (urb->status != 0)
1201                         goto Bad_End;
1202
1203                 if (urb->actual_length == 0) {
1204                         ub_state_stat_counted(sc, cmd);
1205                         return;
1206                 }
1207
1208                 /*
1209                  * Check the returned Bulk protocol status.
1210                  * The status block has to be validated first.
1211                  */
1212
1213                 bcs = &sc->work_bcs;
1214
1215                 if (sc->signature == cpu_to_le32(0)) {
1216                         /*
1217                          * This is the first reply, so do not perform the check.
1218                          * Instead, remember the signature the device uses
1219                          * for future checks. But do not allow a nul.
1220                          */
1221                         sc->signature = bcs->Signature;
1222                         if (sc->signature == cpu_to_le32(0)) {
1223                                 ub_state_stat_counted(sc, cmd);
1224                                 return;
1225                         }
1226                 } else {
1227                         if (bcs->Signature != sc->signature) {
1228                                 ub_state_stat_counted(sc, cmd);
1229                                 return;
1230                         }
1231                 }
1232
1233                 if (bcs->Tag != cmd->tag) {
1234                         /*
1235                          * This usually happens when we disagree with the
1236                          * device's microcode about something. For instance,
1237                          * a few of them throw this after timeouts. They buffer
1238                          * commands and reply at commands we timed out before.
1239                          * Without flushing these replies we loop forever.
1240                          */
1241                         ub_state_stat_counted(sc, cmd);
1242                         return;
1243                 }
1244
1245                 len = le32_to_cpu(bcs->Residue);
1246                 if (len != cmd->len - cmd->act_len) {
1247                         /*
1248                          * It is all right to transfer less, the caller has
1249                          * to check. But it's not all right if the device
1250                          * counts disagree with our counts.
1251                          */
1252                         goto Bad_End;
1253                 }
1254
1255                 switch (bcs->Status) {
1256                 case US_BULK_STAT_OK:
1257                         break;
1258                 case US_BULK_STAT_FAIL:
1259                         ub_state_sense(sc, cmd);
1260                         return;
1261                 case US_BULK_STAT_PHASE:
1262                         goto Bad_End;
1263                 default:
1264                         printk(KERN_INFO "%s: unknown CSW status 0x%x\n",
1265                             sc->name, bcs->Status);
1266                         ub_state_done(sc, cmd, -EINVAL);
1267                         return;
1268                 }
1269
1270                 /* Not zeroing error to preserve a babble indicator */
1271                 if (cmd->error != 0) {
1272                         ub_state_sense(sc, cmd);
1273                         return;
1274                 }
1275                 cmd->state = UB_CMDST_DONE;
1276                 ub_cmdq_pop(sc);
1277                 (*cmd->done)(sc, cmd);
1278
1279         } else if (cmd->state == UB_CMDST_SENSE) {
1280                 ub_state_done(sc, cmd, -EIO);
1281
1282         } else {
1283                 printk(KERN_WARNING "%s: "
1284                     "wrong command state %d\n",
1285                     sc->name, cmd->state);
1286                 ub_state_done(sc, cmd, -EINVAL);
1287                 return;
1288         }
1289         return;
1290
1291 Bad_End: /* Little Excel is dead */
1292         ub_state_done(sc, cmd, -EIO);
1293 }
1294
1295 /*
1296  * Factorization helper for the command state machine:
1297  * Initiate a data segment transfer.
1298  */
1299 static void ub_data_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1300 {
1301         struct scatterlist *sg = &cmd->sgv[cmd->current_sg];
1302         int pipe;
1303         int rc;
1304
1305         UB_INIT_COMPLETION(sc->work_done);
1306
1307         if (cmd->dir == UB_DIR_READ)
1308                 pipe = sc->recv_bulk_pipe;
1309         else
1310                 pipe = sc->send_bulk_pipe;
1311         sc->last_pipe = pipe;
1312         usb_fill_bulk_urb(&sc->work_urb, sc->dev, pipe,
1313             page_address(sg->page) + sg->offset, sg->length,
1314             ub_urb_complete, sc);
1315         sc->work_urb.actual_length = 0;
1316         sc->work_urb.error_count = 0;
1317         sc->work_urb.status = 0;
1318
1319         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
1320                 /* XXX Clear stalls */
1321                 ub_complete(&sc->work_done);
1322                 ub_state_done(sc, cmd, rc);
1323                 return;
1324         }
1325
1326         sc->work_timer.expires = jiffies + UB_DATA_TIMEOUT;
1327         add_timer(&sc->work_timer);
1328
1329         cmd->state = UB_CMDST_DATA;
1330 }
1331
1332 /*
1333  * Factorization helper for the command state machine:
1334  * Finish the command.
1335  */
1336 static void ub_state_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd, int rc)
1337 {
1338
1339         cmd->error = rc;
1340         cmd->state = UB_CMDST_DONE;
1341         ub_cmdq_pop(sc);
1342         (*cmd->done)(sc, cmd);
1343 }
1344
1345 /*
1346  * Factorization helper for the command state machine:
1347  * Submit a CSW read.
1348  */
1349 static int __ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1350 {
1351         int rc;
1352
1353         UB_INIT_COMPLETION(sc->work_done);
1354
1355         sc->last_pipe = sc->recv_bulk_pipe;
1356         usb_fill_bulk_urb(&sc->work_urb, sc->dev, sc->recv_bulk_pipe,
1357             &sc->work_bcs, US_BULK_CS_WRAP_LEN, ub_urb_complete, sc);
1358         sc->work_urb.actual_length = 0;
1359         sc->work_urb.error_count = 0;
1360         sc->work_urb.status = 0;
1361
1362         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
1363                 /* XXX Clear stalls */
1364                 ub_complete(&sc->work_done);
1365                 ub_state_done(sc, cmd, rc);
1366                 return -1;
1367         }
1368
1369         sc->work_timer.expires = jiffies + UB_STAT_TIMEOUT;
1370         add_timer(&sc->work_timer);
1371         return 0;
1372 }
1373
1374 /*
1375  * Factorization helper for the command state machine:
1376  * Submit a CSW read and go to STAT state.
1377  */
1378 static void ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1379 {
1380
1381         if (__ub_state_stat(sc, cmd) != 0)
1382                 return;
1383
1384         cmd->stat_count = 0;
1385         cmd->state = UB_CMDST_STAT;
1386 }
1387
1388 /*
1389  * Factorization helper for the command state machine:
1390  * Submit a CSW read and go to STAT state with counter (along [C] path).
1391  */
1392 static void ub_state_stat_counted(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1393 {
1394
1395         if (++cmd->stat_count >= 4) {
1396                 ub_state_sense(sc, cmd);
1397                 return;
1398         }
1399
1400         if (__ub_state_stat(sc, cmd) != 0)
1401                 return;
1402
1403         cmd->state = UB_CMDST_STAT;
1404 }
1405
1406 /*
1407  * Factorization helper for the command state machine:
1408  * Submit a REQUEST SENSE and go to SENSE state.
1409  */
1410 static void ub_state_sense(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1411 {
1412         struct ub_scsi_cmd *scmd;
1413         struct scatterlist *sg;
1414         int rc;
1415
1416         if (cmd->cdb[0] == REQUEST_SENSE) {
1417                 rc = -EPIPE;
1418                 goto error;
1419         }
1420
1421         scmd = &sc->top_rqs_cmd;
1422         memset(scmd, 0, sizeof(struct ub_scsi_cmd));
1423         scmd->cdb[0] = REQUEST_SENSE;
1424         scmd->cdb[4] = UB_SENSE_SIZE;
1425         scmd->cdb_len = 6;
1426         scmd->dir = UB_DIR_READ;
1427         scmd->state = UB_CMDST_INIT;
1428         scmd->nsg = 1;
1429         sg = &scmd->sgv[0];
1430         sg->page = virt_to_page(sc->top_sense);
1431         sg->offset = (unsigned long)sc->top_sense & (PAGE_SIZE-1);
1432         sg->length = UB_SENSE_SIZE;
1433         scmd->len = UB_SENSE_SIZE;
1434         scmd->lun = cmd->lun;
1435         scmd->done = ub_top_sense_done;
1436         scmd->back = cmd;
1437
1438         scmd->tag = sc->tagcnt++;
1439
1440         cmd->state = UB_CMDST_SENSE;
1441
1442         ub_cmdq_insert(sc, scmd);
1443         return;
1444
1445 error:
1446         ub_state_done(sc, cmd, rc);
1447 }
1448
1449 /*
1450  * A helper for the command's state machine:
1451  * Submit a stall clear.
1452  */
1453 static int ub_submit_clear_stall(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
1454     int stalled_pipe)
1455 {
1456         int endp;
1457         struct usb_ctrlrequest *cr;
1458         int rc;
1459
1460         endp = usb_pipeendpoint(stalled_pipe);
1461         if (usb_pipein (stalled_pipe))
1462                 endp |= USB_DIR_IN;
1463
1464         cr = &sc->work_cr;
1465         cr->bRequestType = USB_RECIP_ENDPOINT;
1466         cr->bRequest = USB_REQ_CLEAR_FEATURE;
1467         cr->wValue = cpu_to_le16(USB_ENDPOINT_HALT);
1468         cr->wIndex = cpu_to_le16(endp);
1469         cr->wLength = cpu_to_le16(0);
1470
1471         UB_INIT_COMPLETION(sc->work_done);
1472
1473         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->send_ctrl_pipe,
1474             (unsigned char*) cr, NULL, 0, ub_urb_complete, sc);
1475         sc->work_urb.actual_length = 0;
1476         sc->work_urb.error_count = 0;
1477         sc->work_urb.status = 0;
1478
1479         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
1480                 ub_complete(&sc->work_done);
1481                 return rc;
1482         }
1483
1484         sc->work_timer.expires = jiffies + UB_CTRL_TIMEOUT;
1485         add_timer(&sc->work_timer);
1486         return 0;
1487 }
1488
1489 /*
1490  */
1491 static void ub_top_sense_done(struct ub_dev *sc, struct ub_scsi_cmd *scmd)
1492 {
1493         unsigned char *sense = sc->top_sense;
1494         struct ub_scsi_cmd *cmd;
1495
1496         /*
1497          * Find the command which triggered the unit attention or a check,
1498          * save the sense into it, and advance its state machine.
1499          */
1500         if ((cmd = ub_cmdq_peek(sc)) == NULL) {
1501                 printk(KERN_WARNING "%s: sense done while idle\n", sc->name);
1502                 return;
1503         }
1504         if (cmd != scmd->back) {
1505                 printk(KERN_WARNING "%s: "
1506                     "sense done for wrong command 0x%x\n",
1507                     sc->name, cmd->tag);
1508                 return;
1509         }
1510         if (cmd->state != UB_CMDST_SENSE) {
1511                 printk(KERN_WARNING "%s: "
1512                     "sense done with bad cmd state %d\n",
1513                     sc->name, cmd->state);
1514                 return;
1515         }
1516
1517         /*
1518          * Ignoring scmd->act_len, because the buffer was pre-zeroed.
1519          */
1520         cmd->key = sense[2] & 0x0F;
1521         cmd->asc = sense[12];
1522         cmd->ascq = sense[13];
1523
1524         ub_scsi_urb_compl(sc, cmd);
1525 }
1526
1527 /*
1528  * Reset management
1529  * XXX Move usb_reset_device to khubd. Hogging kevent is not a good thing.
1530  * XXX Make usb_sync_reset asynchronous.
1531  */
1532
1533 static void ub_reset_enter(struct ub_dev *sc, int try)
1534 {
1535
1536         if (sc->reset) {
1537                 /* This happens often on multi-LUN devices. */
1538                 return;
1539         }
1540         sc->reset = try + 1;
1541
1542 #if 0 /* Not needed because the disconnect waits for us. */
1543         unsigned long flags;
1544         spin_lock_irqsave(&ub_lock, flags);
1545         sc->openc++;
1546         spin_unlock_irqrestore(&ub_lock, flags);
1547 #endif
1548
1549 #if 0 /* We let them stop themselves. */
1550         struct list_head *p;
1551         struct ub_lun *lun;
1552         list_for_each(p, &sc->luns) {
1553                 lun = list_entry(p, struct ub_lun, link);
1554                 blk_stop_queue(lun->disk->queue);
1555         }
1556 #endif
1557
1558         schedule_work(&sc->reset_work);
1559 }
1560
1561 static void ub_reset_task(void *arg)
1562 {
1563         struct ub_dev *sc = arg;
1564         unsigned long flags;
1565         struct list_head *p;
1566         struct ub_lun *lun;
1567         int lkr, rc;
1568
1569         if (!sc->reset) {
1570                 printk(KERN_WARNING "%s: Running reset unrequested\n",
1571                     sc->name);
1572                 return;
1573         }
1574
1575         if (atomic_read(&sc->poison)) {
1576                 ;
1577         } else if ((sc->reset & 1) == 0) {
1578                 ub_sync_reset(sc);
1579                 msleep(700);    /* usb-storage sleeps 6s (!) */
1580                 ub_probe_clear_stall(sc, sc->recv_bulk_pipe);
1581                 ub_probe_clear_stall(sc, sc->send_bulk_pipe);
1582         } else if (sc->dev->actconfig->desc.bNumInterfaces != 1) {
1583                 ;
1584         } else {
1585                 if ((lkr = usb_lock_device_for_reset(sc->dev, sc->intf)) < 0) {
1586                         printk(KERN_NOTICE
1587                             "%s: usb_lock_device_for_reset failed (%d)\n",
1588                             sc->name, lkr);
1589                 } else {
1590                         rc = usb_reset_device(sc->dev);
1591                         if (rc < 0) {
1592                                 printk(KERN_NOTICE "%s: "
1593                                     "usb_lock_device_for_reset failed (%d)\n",
1594                                     sc->name, rc);
1595                         }
1596
1597                         if (lkr)
1598                                 usb_unlock_device(sc->dev);
1599                 }
1600         }
1601
1602         /*
1603          * In theory, no commands can be running while reset is active,
1604          * so nobody can ask for another reset, and so we do not need any
1605          * queues of resets or anything. We do need a spinlock though,
1606          * to interact with block layer.
1607          */
1608         spin_lock_irqsave(sc->lock, flags);
1609         sc->reset = 0;
1610         tasklet_schedule(&sc->tasklet);
1611         list_for_each(p, &sc->luns) {
1612                 lun = list_entry(p, struct ub_lun, link);
1613                 blk_start_queue(lun->disk->queue);
1614         }
1615         wake_up(&sc->reset_wait);
1616         spin_unlock_irqrestore(sc->lock, flags);
1617 }
1618
1619 /*
1620  * This is called from a process context.
1621  */
1622 static void ub_revalidate(struct ub_dev *sc, struct ub_lun *lun)
1623 {
1624
1625         lun->readonly = 0;      /* XXX Query this from the device */
1626
1627         lun->capacity.nsec = 0;
1628         lun->capacity.bsize = 512;
1629         lun->capacity.bshift = 0;
1630
1631         if (ub_sync_tur(sc, lun) != 0)
1632                 return;                 /* Not ready */
1633         lun->changed = 0;
1634
1635         if (ub_sync_read_cap(sc, lun, &lun->capacity) != 0) {
1636                 /*
1637                  * The retry here means something is wrong, either with the
1638                  * device, with the transport, or with our code.
1639                  * We keep this because sd.c has retries for capacity.
1640                  */
1641                 if (ub_sync_read_cap(sc, lun, &lun->capacity) != 0) {
1642                         lun->capacity.nsec = 0;
1643                         lun->capacity.bsize = 512;
1644                         lun->capacity.bshift = 0;
1645                 }
1646         }
1647 }
1648
1649 /*
1650  * The open funcion.
1651  * This is mostly needed to keep refcounting, but also to support
1652  * media checks on removable media drives.
1653  */
1654 static int ub_bd_open(struct inode *inode, struct file *filp)
1655 {
1656         struct gendisk *disk = inode->i_bdev->bd_disk;
1657         struct ub_lun *lun = disk->private_data;
1658         struct ub_dev *sc = lun->udev;
1659         unsigned long flags;
1660         int rc;
1661
1662         spin_lock_irqsave(&ub_lock, flags);
1663         if (atomic_read(&sc->poison)) {
1664                 spin_unlock_irqrestore(&ub_lock, flags);
1665                 return -ENXIO;
1666         }
1667         sc->openc++;
1668         spin_unlock_irqrestore(&ub_lock, flags);
1669
1670         if (lun->removable || lun->readonly)
1671                 check_disk_change(inode->i_bdev);
1672
1673         /*
1674          * The sd.c considers ->media_present and ->changed not equivalent,
1675          * under some pretty murky conditions (a failure of READ CAPACITY).
1676          * We may need it one day.
1677          */
1678         if (lun->removable && lun->changed && !(filp->f_flags & O_NDELAY)) {
1679                 rc = -ENOMEDIUM;
1680                 goto err_open;
1681         }
1682
1683         if (lun->readonly && (filp->f_mode & FMODE_WRITE)) {
1684                 rc = -EROFS;
1685                 goto err_open;
1686         }
1687
1688         return 0;
1689
1690 err_open:
1691         ub_put(sc);
1692         return rc;
1693 }
1694
1695 /*
1696  */
1697 static int ub_bd_release(struct inode *inode, struct file *filp)
1698 {
1699         struct gendisk *disk = inode->i_bdev->bd_disk;
1700         struct ub_lun *lun = disk->private_data;
1701         struct ub_dev *sc = lun->udev;
1702
1703         ub_put(sc);
1704         return 0;
1705 }
1706
1707 /*
1708  * The ioctl interface.
1709  */
1710 static int ub_bd_ioctl(struct inode *inode, struct file *filp,
1711     unsigned int cmd, unsigned long arg)
1712 {
1713         struct gendisk *disk = inode->i_bdev->bd_disk;
1714         void __user *usermem = (void __user *) arg;
1715
1716         return scsi_cmd_ioctl(filp, disk, cmd, usermem);
1717 }
1718
1719 /*
1720  * This is called once a new disk was seen by the block layer or by ub_probe().
1721  * The main onjective here is to discover the features of the media such as
1722  * the capacity, read-only status, etc. USB storage generally does not
1723  * need to be spun up, but if we needed it, this would be the place.
1724  *
1725  * This call can sleep.
1726  *
1727  * The return code is not used.
1728  */
1729 static int ub_bd_revalidate(struct gendisk *disk)
1730 {
1731         struct ub_lun *lun = disk->private_data;
1732
1733         ub_revalidate(lun->udev, lun);
1734
1735         /* XXX Support sector size switching like in sr.c */
1736         blk_queue_hardsect_size(disk->queue, lun->capacity.bsize);
1737         set_capacity(disk, lun->capacity.nsec);
1738         // set_disk_ro(sdkp->disk, lun->readonly);
1739
1740         return 0;
1741 }
1742
1743 /*
1744  * The check is called by the block layer to verify if the media
1745  * is still available. It is supposed to be harmless, lightweight and
1746  * non-intrusive in case the media was not changed.
1747  *
1748  * This call can sleep.
1749  *
1750  * The return code is bool!
1751  */
1752 static int ub_bd_media_changed(struct gendisk *disk)
1753 {
1754         struct ub_lun *lun = disk->private_data;
1755
1756         if (!lun->removable)
1757                 return 0;
1758
1759         /*
1760          * We clean checks always after every command, so this is not
1761          * as dangerous as it looks. If the TEST_UNIT_READY fails here,
1762          * the device is actually not ready with operator or software
1763          * intervention required. One dangerous item might be a drive which
1764          * spins itself down, and come the time to write dirty pages, this
1765          * will fail, then block layer discards the data. Since we never
1766          * spin drives up, such devices simply cannot be used with ub anyway.
1767          */
1768         if (ub_sync_tur(lun->udev, lun) != 0) {
1769                 lun->changed = 1;
1770                 return 1;
1771         }
1772
1773         return lun->changed;
1774 }
1775
1776 static struct block_device_operations ub_bd_fops = {
1777         .owner          = THIS_MODULE,
1778         .open           = ub_bd_open,
1779         .release        = ub_bd_release,
1780         .ioctl          = ub_bd_ioctl,
1781         .media_changed  = ub_bd_media_changed,
1782         .revalidate_disk = ub_bd_revalidate,
1783 };
1784
1785 /*
1786  * Common ->done routine for commands executed synchronously.
1787  */
1788 static void ub_probe_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1789 {
1790         struct completion *cop = cmd->back;
1791         complete(cop);
1792 }
1793
1794 /*
1795  * Test if the device has a check condition on it, synchronously.
1796  */
1797 static int ub_sync_tur(struct ub_dev *sc, struct ub_lun *lun)
1798 {
1799         struct ub_scsi_cmd *cmd;
1800         enum { ALLOC_SIZE = sizeof(struct ub_scsi_cmd) };
1801         unsigned long flags;
1802         struct completion compl;
1803         int rc;
1804
1805         init_completion(&compl);
1806
1807         rc = -ENOMEM;
1808         if ((cmd = kzalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
1809                 goto err_alloc;
1810
1811         cmd->cdb[0] = TEST_UNIT_READY;
1812         cmd->cdb_len = 6;
1813         cmd->dir = UB_DIR_NONE;
1814         cmd->state = UB_CMDST_INIT;
1815         cmd->lun = lun;                 /* This may be NULL, but that's ok */
1816         cmd->done = ub_probe_done;
1817         cmd->back = &compl;
1818
1819         spin_lock_irqsave(sc->lock, flags);
1820         cmd->tag = sc->tagcnt++;
1821
1822         rc = ub_submit_scsi(sc, cmd);
1823         spin_unlock_irqrestore(sc->lock, flags);
1824
1825         if (rc != 0)
1826                 goto err_submit;
1827
1828         wait_for_completion(&compl);
1829
1830         rc = cmd->error;
1831
1832         if (rc == -EIO && cmd->key != 0)        /* Retries for benh's key */
1833                 rc = cmd->key;
1834
1835 err_submit:
1836         kfree(cmd);
1837 err_alloc:
1838         return rc;
1839 }
1840
1841 /*
1842  * Read the SCSI capacity synchronously (for probing).
1843  */
1844 static int ub_sync_read_cap(struct ub_dev *sc, struct ub_lun *lun,
1845     struct ub_capacity *ret)
1846 {
1847         struct ub_scsi_cmd *cmd;
1848         struct scatterlist *sg;
1849         char *p;
1850         enum { ALLOC_SIZE = sizeof(struct ub_scsi_cmd) + 8 };
1851         unsigned long flags;
1852         unsigned int bsize, shift;
1853         unsigned long nsec;
1854         struct completion compl;
1855         int rc;
1856
1857         init_completion(&compl);
1858
1859         rc = -ENOMEM;
1860         if ((cmd = kzalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
1861                 goto err_alloc;
1862         p = (char *)cmd + sizeof(struct ub_scsi_cmd);
1863
1864         cmd->cdb[0] = 0x25;
1865         cmd->cdb_len = 10;
1866         cmd->dir = UB_DIR_READ;
1867         cmd->state = UB_CMDST_INIT;
1868         cmd->nsg = 1;
1869         sg = &cmd->sgv[0];
1870         sg->page = virt_to_page(p);
1871         sg->offset = (unsigned long)p & (PAGE_SIZE-1);
1872         sg->length = 8;
1873         cmd->len = 8;
1874         cmd->lun = lun;
1875         cmd->done = ub_probe_done;
1876         cmd->back = &compl;
1877
1878         spin_lock_irqsave(sc->lock, flags);
1879         cmd->tag = sc->tagcnt++;
1880
1881         rc = ub_submit_scsi(sc, cmd);
1882         spin_unlock_irqrestore(sc->lock, flags);
1883
1884         if (rc != 0)
1885                 goto err_submit;
1886
1887         wait_for_completion(&compl);
1888
1889         if (cmd->error != 0) {
1890                 rc = -EIO;
1891                 goto err_read;
1892         }
1893         if (cmd->act_len != 8) {
1894                 rc = -EIO;
1895                 goto err_read;
1896         }
1897
1898         /* sd.c special-cases sector size of 0 to mean 512. Needed? Safe? */
1899         nsec = be32_to_cpu(*(__be32 *)p) + 1;
1900         bsize = be32_to_cpu(*(__be32 *)(p + 4));
1901         switch (bsize) {
1902         case 512:       shift = 0;      break;
1903         case 1024:      shift = 1;      break;
1904         case 2048:      shift = 2;      break;
1905         case 4096:      shift = 3;      break;
1906         default:
1907                 rc = -EDOM;
1908                 goto err_inv_bsize;
1909         }
1910
1911         ret->bsize = bsize;
1912         ret->bshift = shift;
1913         ret->nsec = nsec << shift;
1914         rc = 0;
1915
1916 err_inv_bsize:
1917 err_read:
1918 err_submit:
1919         kfree(cmd);
1920 err_alloc:
1921         return rc;
1922 }
1923
1924 /*
1925  */
1926 static void ub_probe_urb_complete(struct urb *urb, struct pt_regs *pt)
1927 {
1928         struct completion *cop = urb->context;
1929         complete(cop);
1930 }
1931
1932 static void ub_probe_timeout(unsigned long arg)
1933 {
1934         struct completion *cop = (struct completion *) arg;
1935         complete(cop);
1936 }
1937
1938 /*
1939  * Reset with a Bulk reset.
1940  */
1941 static int ub_sync_reset(struct ub_dev *sc)
1942 {
1943         int ifnum = sc->intf->cur_altsetting->desc.bInterfaceNumber;
1944         struct usb_ctrlrequest *cr;
1945         struct completion compl;
1946         struct timer_list timer;
1947         int rc;
1948
1949         init_completion(&compl);
1950
1951         cr = &sc->work_cr;
1952         cr->bRequestType = USB_TYPE_CLASS | USB_RECIP_INTERFACE;
1953         cr->bRequest = US_BULK_RESET_REQUEST;
1954         cr->wValue = cpu_to_le16(0);
1955         cr->wIndex = cpu_to_le16(ifnum);
1956         cr->wLength = cpu_to_le16(0);
1957
1958         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->send_ctrl_pipe,
1959             (unsigned char*) cr, NULL, 0, ub_probe_urb_complete, &compl);
1960         sc->work_urb.actual_length = 0;
1961         sc->work_urb.error_count = 0;
1962         sc->work_urb.status = 0;
1963
1964         if ((rc = usb_submit_urb(&sc->work_urb, GFP_KERNEL)) != 0) {
1965                 printk(KERN_WARNING
1966                      "%s: Unable to submit a bulk reset (%d)\n", sc->name, rc);
1967                 return rc;
1968         }
1969
1970         init_timer(&timer);
1971         timer.function = ub_probe_timeout;
1972         timer.data = (unsigned long) &compl;
1973         timer.expires = jiffies + UB_CTRL_TIMEOUT;
1974         add_timer(&timer);
1975
1976         wait_for_completion(&compl);
1977
1978         del_timer_sync(&timer);
1979         usb_kill_urb(&sc->work_urb);
1980
1981         return sc->work_urb.status;
1982 }
1983
1984 /*
1985  * Get number of LUNs by the way of Bulk GetMaxLUN command.
1986  */
1987 static int ub_sync_getmaxlun(struct ub_dev *sc)
1988 {
1989         int ifnum = sc->intf->cur_altsetting->desc.bInterfaceNumber;
1990         unsigned char *p;
1991         enum { ALLOC_SIZE = 1 };
1992         struct usb_ctrlrequest *cr;
1993         struct completion compl;
1994         struct timer_list timer;
1995         int nluns;
1996         int rc;
1997
1998         init_completion(&compl);
1999
2000         rc = -ENOMEM;
2001         if ((p = kmalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
2002                 goto err_alloc;
2003         *p = 55;
2004
2005         cr = &sc->work_cr;
2006         cr->bRequestType = USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE;
2007         cr->bRequest = US_BULK_GET_MAX_LUN;
2008         cr->wValue = cpu_to_le16(0);
2009         cr->wIndex = cpu_to_le16(ifnum);
2010         cr->wLength = cpu_to_le16(1);
2011
2012         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->recv_ctrl_pipe,
2013             (unsigned char*) cr, p, 1, ub_probe_urb_complete, &compl);
2014         sc->work_urb.actual_length = 0;
2015         sc->work_urb.error_count = 0;
2016         sc->work_urb.status = 0;
2017
2018         if ((rc = usb_submit_urb(&sc->work_urb, GFP_KERNEL)) != 0)
2019                 goto err_submit;
2020
2021         init_timer(&timer);
2022         timer.function = ub_probe_timeout;
2023         timer.data = (unsigned long) &compl;
2024         timer.expires = jiffies + UB_CTRL_TIMEOUT;
2025         add_timer(&timer);
2026
2027         wait_for_completion(&compl);
2028
2029         del_timer_sync(&timer);
2030         usb_kill_urb(&sc->work_urb);
2031
2032         if ((rc = sc->work_urb.status) < 0)
2033                 goto err_io;
2034
2035         if (sc->work_urb.actual_length != 1) {
2036                 nluns = 0;
2037         } else {
2038                 if ((nluns = *p) == 55) {
2039                         nluns = 0;
2040                 } else {
2041                         /* GetMaxLUN returns the maximum LUN number */
2042                         nluns += 1;
2043                         if (nluns > UB_MAX_LUNS)
2044                                 nluns = UB_MAX_LUNS;
2045                 }
2046         }
2047
2048         kfree(p);
2049         return nluns;
2050
2051 err_io:
2052 err_submit:
2053         kfree(p);
2054 err_alloc:
2055         return rc;
2056 }
2057
2058 /*
2059  * Clear initial stalls.
2060  */
2061 static int ub_probe_clear_stall(struct ub_dev *sc, int stalled_pipe)
2062 {
2063         int endp;
2064         struct usb_ctrlrequest *cr;
2065         struct completion compl;
2066         struct timer_list timer;
2067         int rc;
2068
2069         init_completion(&compl);
2070
2071         endp = usb_pipeendpoint(stalled_pipe);
2072         if (usb_pipein (stalled_pipe))
2073                 endp |= USB_DIR_IN;
2074
2075         cr = &sc->work_cr;
2076         cr->bRequestType = USB_RECIP_ENDPOINT;
2077         cr->bRequest = USB_REQ_CLEAR_FEATURE;
2078         cr->wValue = cpu_to_le16(USB_ENDPOINT_HALT);
2079         cr->wIndex = cpu_to_le16(endp);
2080         cr->wLength = cpu_to_le16(0);
2081
2082         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->send_ctrl_pipe,
2083             (unsigned char*) cr, NULL, 0, ub_probe_urb_complete, &compl);
2084         sc->work_urb.actual_length = 0;
2085         sc->work_urb.error_count = 0;
2086         sc->work_urb.status = 0;
2087
2088         if ((rc = usb_submit_urb(&sc->work_urb, GFP_KERNEL)) != 0) {
2089                 printk(KERN_WARNING
2090                      "%s: Unable to submit a probe clear (%d)\n", sc->name, rc);
2091                 return rc;
2092         }
2093
2094         init_timer(&timer);
2095         timer.function = ub_probe_timeout;
2096         timer.data = (unsigned long) &compl;
2097         timer.expires = jiffies + UB_CTRL_TIMEOUT;
2098         add_timer(&timer);
2099
2100         wait_for_completion(&compl);
2101
2102         del_timer_sync(&timer);
2103         usb_kill_urb(&sc->work_urb);
2104
2105         /* reset the endpoint toggle */
2106         usb_settoggle(sc->dev, endp, usb_pipeout(sc->last_pipe), 0);
2107
2108         return 0;
2109 }
2110
2111 /*
2112  * Get the pipe settings.
2113  */
2114 static int ub_get_pipes(struct ub_dev *sc, struct usb_device *dev,
2115     struct usb_interface *intf)
2116 {
2117         struct usb_host_interface *altsetting = intf->cur_altsetting;
2118         struct usb_endpoint_descriptor *ep_in = NULL;
2119         struct usb_endpoint_descriptor *ep_out = NULL;
2120         struct usb_endpoint_descriptor *ep;
2121         int i;
2122
2123         /*
2124          * Find the endpoints we need.
2125          * We are expecting a minimum of 2 endpoints - in and out (bulk).
2126          * We will ignore any others.
2127          */
2128         for (i = 0; i < altsetting->desc.bNumEndpoints; i++) {
2129                 ep = &altsetting->endpoint[i].desc;
2130
2131                 /* Is it a BULK endpoint? */
2132                 if ((ep->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK)
2133                                 == USB_ENDPOINT_XFER_BULK) {
2134                         /* BULK in or out? */
2135                         if (ep->bEndpointAddress & USB_DIR_IN)
2136                                 ep_in = ep;
2137                         else
2138                                 ep_out = ep;
2139                 }
2140         }
2141
2142         if (ep_in == NULL || ep_out == NULL) {
2143                 printk(KERN_NOTICE "%s: failed endpoint check\n",
2144                     sc->name);
2145                 return -ENODEV;
2146         }
2147
2148         /* Calculate and store the pipe values */
2149         sc->send_ctrl_pipe = usb_sndctrlpipe(dev, 0);
2150         sc->recv_ctrl_pipe = usb_rcvctrlpipe(dev, 0);
2151         sc->send_bulk_pipe = usb_sndbulkpipe(dev,
2152                 ep_out->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2153         sc->recv_bulk_pipe = usb_rcvbulkpipe(dev,
2154                 ep_in->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2155
2156         return 0;
2157 }
2158
2159 /*
2160  * Probing is done in the process context, which allows us to cheat
2161  * and not to build a state machine for the discovery.
2162  */
2163 static int ub_probe(struct usb_interface *intf,
2164     const struct usb_device_id *dev_id)
2165 {
2166         struct ub_dev *sc;
2167         int nluns;
2168         int rc;
2169         int i;
2170
2171         if (usb_usual_check_type(dev_id, USB_US_TYPE_UB))
2172                 return -ENXIO;
2173
2174         rc = -ENOMEM;
2175         if ((sc = kzalloc(sizeof(struct ub_dev), GFP_KERNEL)) == NULL)
2176                 goto err_core;
2177         sc->lock = ub_next_lock();
2178         INIT_LIST_HEAD(&sc->luns);
2179         usb_init_urb(&sc->work_urb);
2180         tasklet_init(&sc->tasklet, ub_scsi_action, (unsigned long)sc);
2181         atomic_set(&sc->poison, 0);
2182         INIT_WORK(&sc->reset_work, ub_reset_task, sc);
2183         init_waitqueue_head(&sc->reset_wait);
2184
2185         init_timer(&sc->work_timer);
2186         sc->work_timer.data = (unsigned long) sc;
2187         sc->work_timer.function = ub_urb_timeout;
2188
2189         ub_init_completion(&sc->work_done);
2190         sc->work_done.done = 1;         /* A little yuk, but oh well... */
2191
2192         sc->dev = interface_to_usbdev(intf);
2193         sc->intf = intf;
2194         // sc->ifnum = intf->cur_altsetting->desc.bInterfaceNumber;
2195         usb_set_intfdata(intf, sc);
2196         usb_get_dev(sc->dev);
2197         /*
2198          * Since we give the interface struct to the block level through
2199          * disk->driverfs_dev, we have to pin it. Otherwise, block_uevent
2200          * oopses on close after a disconnect (kernels 2.6.16 and up).
2201          */
2202         usb_get_intf(sc->intf);
2203
2204         snprintf(sc->name, 12, DRV_NAME "(%d.%d)",
2205             sc->dev->bus->busnum, sc->dev->devnum);
2206
2207         /* XXX Verify that we can handle the device (from descriptors) */
2208
2209         if (ub_get_pipes(sc, sc->dev, intf) != 0)
2210                 goto err_dev_desc;
2211
2212         /*
2213          * At this point, all USB initialization is done, do upper layer.
2214          * We really hate halfway initialized structures, so from the
2215          * invariants perspective, this ub_dev is fully constructed at
2216          * this point.
2217          */
2218
2219         /*
2220          * This is needed to clear toggles. It is a problem only if we do
2221          * `rmmod ub && modprobe ub` without disconnects, but we like that.
2222          */
2223 #if 0 /* iPod Mini fails if we do this (big white iPod works) */
2224         ub_probe_clear_stall(sc, sc->recv_bulk_pipe);
2225         ub_probe_clear_stall(sc, sc->send_bulk_pipe);
2226 #endif
2227
2228         /*
2229          * The way this is used by the startup code is a little specific.
2230          * A SCSI check causes a USB stall. Our common case code sees it
2231          * and clears the check, after which the device is ready for use.
2232          * But if a check was not present, any command other than
2233          * TEST_UNIT_READY ends with a lockup (including REQUEST_SENSE).
2234          *
2235          * If we neglect to clear the SCSI check, the first real command fails
2236          * (which is the capacity readout). We clear that and retry, but why
2237          * causing spurious retries for no reason.
2238          *
2239          * Revalidation may start with its own TEST_UNIT_READY, but that one
2240          * has to succeed, so we clear checks with an additional one here.
2241          * In any case it's not our business how revaliadation is implemented.
2242          */
2243         for (i = 0; i < 3; i++) {  /* Retries for the schwag key from KS'04 */
2244                 if ((rc = ub_sync_tur(sc, NULL)) <= 0) break;
2245                 if (rc != 0x6) break;
2246                 msleep(10);
2247         }
2248
2249         nluns = 1;
2250         for (i = 0; i < 3; i++) {
2251                 if ((rc = ub_sync_getmaxlun(sc)) < 0)
2252                         break;
2253                 if (rc != 0) {
2254                         nluns = rc;
2255                         break;
2256                 }
2257                 msleep(100);
2258         }
2259
2260         for (i = 0; i < nluns; i++) {
2261                 ub_probe_lun(sc, i);
2262         }
2263         return 0;
2264
2265 err_dev_desc:
2266         usb_set_intfdata(intf, NULL);
2267         usb_put_intf(sc->intf);
2268         usb_put_dev(sc->dev);
2269         kfree(sc);
2270 err_core:
2271         return rc;
2272 }
2273
2274 static int ub_probe_lun(struct ub_dev *sc, int lnum)
2275 {
2276         struct ub_lun *lun;
2277         request_queue_t *q;
2278         struct gendisk *disk;
2279         int rc;
2280
2281         rc = -ENOMEM;
2282         if ((lun = kzalloc(sizeof(struct ub_lun), GFP_KERNEL)) == NULL)
2283                 goto err_alloc;
2284         lun->num = lnum;
2285
2286         rc = -ENOSR;
2287         if ((lun->id = ub_id_get()) == -1)
2288                 goto err_id;
2289
2290         lun->udev = sc;
2291
2292         snprintf(lun->name, 16, DRV_NAME "%c(%d.%d.%d)",
2293             lun->id + 'a', sc->dev->bus->busnum, sc->dev->devnum, lun->num);
2294
2295         lun->removable = 1;             /* XXX Query this from the device */
2296         lun->changed = 1;               /* ub_revalidate clears only */
2297         ub_revalidate(sc, lun);
2298
2299         rc = -ENOMEM;
2300         if ((disk = alloc_disk(UB_PARTS_PER_LUN)) == NULL)
2301                 goto err_diskalloc;
2302
2303         sprintf(disk->disk_name, DRV_NAME "%c", lun->id + 'a');
2304         disk->major = UB_MAJOR;
2305         disk->first_minor = lun->id * UB_PARTS_PER_LUN;
2306         disk->fops = &ub_bd_fops;
2307         disk->private_data = lun;
2308         disk->driverfs_dev = &sc->intf->dev;
2309
2310         rc = -ENOMEM;
2311         if ((q = blk_init_queue(ub_request_fn, sc->lock)) == NULL)
2312                 goto err_blkqinit;
2313
2314         disk->queue = q;
2315
2316         blk_queue_bounce_limit(q, BLK_BOUNCE_HIGH);
2317         blk_queue_max_hw_segments(q, UB_MAX_REQ_SG);
2318         blk_queue_max_phys_segments(q, UB_MAX_REQ_SG);
2319         blk_queue_segment_boundary(q, 0xffffffff);      /* Dubious. */
2320         blk_queue_max_sectors(q, UB_MAX_SECTORS);
2321         blk_queue_hardsect_size(q, lun->capacity.bsize);
2322
2323         lun->disk = disk;
2324         q->queuedata = lun;
2325         list_add(&lun->link, &sc->luns);
2326
2327         set_capacity(disk, lun->capacity.nsec);
2328         if (lun->removable)
2329                 disk->flags |= GENHD_FL_REMOVABLE;
2330
2331         add_disk(disk);
2332
2333         return 0;
2334
2335 err_blkqinit:
2336         put_disk(disk);
2337 err_diskalloc:
2338         ub_id_put(lun->id);
2339 err_id:
2340         kfree(lun);
2341 err_alloc:
2342         return rc;
2343 }
2344
2345 static void ub_disconnect(struct usb_interface *intf)
2346 {
2347         struct ub_dev *sc = usb_get_intfdata(intf);
2348         struct list_head *p;
2349         struct ub_lun *lun;
2350         unsigned long flags;
2351
2352         /*
2353          * Prevent ub_bd_release from pulling the rug from under us.
2354          * XXX This is starting to look like a kref.
2355          * XXX Why not to take this ref at probe time?
2356          */
2357         spin_lock_irqsave(&ub_lock, flags);
2358         sc->openc++;
2359         spin_unlock_irqrestore(&ub_lock, flags);
2360
2361         /*
2362          * Fence stall clearnings, operations triggered by unlinkings and so on.
2363          * We do not attempt to unlink any URBs, because we do not trust the
2364          * unlink paths in HC drivers. Also, we get -84 upon disconnect anyway.
2365          */
2366         atomic_set(&sc->poison, 1);
2367
2368         /*
2369          * Wait for reset to end, if any.
2370          */
2371         wait_event(sc->reset_wait, !sc->reset);
2372
2373         /*
2374          * Blow away queued commands.
2375          *
2376          * Actually, this never works, because before we get here
2377          * the HCD terminates outstanding URB(s). It causes our
2378          * SCSI command queue to advance, commands fail to submit,
2379          * and the whole queue drains. So, we just use this code to
2380          * print warnings.
2381          */
2382         spin_lock_irqsave(sc->lock, flags);
2383         {
2384                 struct ub_scsi_cmd *cmd;
2385                 int cnt = 0;
2386                 while ((cmd = ub_cmdq_peek(sc)) != NULL) {
2387                         cmd->error = -ENOTCONN;
2388                         cmd->state = UB_CMDST_DONE;
2389                         ub_cmdq_pop(sc);
2390                         (*cmd->done)(sc, cmd);
2391                         cnt++;
2392                 }
2393                 if (cnt != 0) {
2394                         printk(KERN_WARNING "%s: "
2395                             "%d was queued after shutdown\n", sc->name, cnt);
2396                 }
2397         }
2398         spin_unlock_irqrestore(sc->lock, flags);
2399
2400         /*
2401          * Unregister the upper layer.
2402          */
2403         list_for_each (p, &sc->luns) {
2404                 lun = list_entry(p, struct ub_lun, link);
2405                 del_gendisk(lun->disk);
2406                 /*
2407                  * I wish I could do:
2408                  *    set_bit(QUEUE_FLAG_DEAD, &q->queue_flags);
2409                  * As it is, we rely on our internal poisoning and let
2410                  * the upper levels to spin furiously failing all the I/O.
2411                  */
2412         }
2413
2414         /*
2415          * Testing for -EINPROGRESS is always a bug, so we are bending
2416          * the rules a little.
2417          */
2418         spin_lock_irqsave(sc->lock, flags);
2419         if (sc->work_urb.status == -EINPROGRESS) {      /* janitors: ignore */
2420                 printk(KERN_WARNING "%s: "
2421                     "URB is active after disconnect\n", sc->name);
2422         }
2423         spin_unlock_irqrestore(sc->lock, flags);
2424
2425         /*
2426          * There is virtually no chance that other CPU runs times so long
2427          * after ub_urb_complete should have called del_timer, but only if HCD
2428          * didn't forget to deliver a callback on unlink.
2429          */
2430         del_timer_sync(&sc->work_timer);
2431
2432         /*
2433          * At this point there must be no commands coming from anyone
2434          * and no URBs left in transit.
2435          */
2436
2437         ub_put(sc);
2438 }
2439
2440 static struct usb_driver ub_driver = {
2441         .name =         "ub",
2442         .probe =        ub_probe,
2443         .disconnect =   ub_disconnect,
2444         .id_table =     ub_usb_ids,
2445 };
2446
2447 static int __init ub_init(void)
2448 {
2449         int rc;
2450         int i;
2451
2452         for (i = 0; i < UB_QLOCK_NUM; i++)
2453                 spin_lock_init(&ub_qlockv[i]);
2454
2455         if ((rc = register_blkdev(UB_MAJOR, DRV_NAME)) != 0)
2456                 goto err_regblkdev;
2457
2458         if ((rc = usb_register(&ub_driver)) != 0)
2459                 goto err_register;
2460
2461         usb_usual_set_present(USB_US_TYPE_UB);
2462         return 0;
2463
2464 err_register:
2465         unregister_blkdev(UB_MAJOR, DRV_NAME);
2466 err_regblkdev:
2467         return rc;
2468 }
2469
2470 static void __exit ub_exit(void)
2471 {
2472         usb_deregister(&ub_driver);
2473
2474         unregister_blkdev(UB_MAJOR, DRV_NAME);
2475         usb_usual_clear_present(USB_US_TYPE_UB);
2476 }
2477
2478 module_init(ub_init);
2479 module_exit(ub_exit);
2480
2481 MODULE_LICENSE("GPL");