drivers/block/ub.c

   1 /*
   2  * The low performance USB storage driver (ub).
   3  *
   4  * Copyright (c) 1999, 2000 Matthew Dharm (mdharm-usb@one-eyed-alien.net)
   5  * Copyright (C) 2004 Pete Zaitcev (zaitcev@yahoo.com)
   6  *
   7  * This work is a part of Linux kernel, is derived from it,
   8  * and is not licensed separately. See file COPYING for details.
   9  *
  10  * TODO (sorted by decreasing priority)
  11  *  -- Return sense now that rq allows it (we always auto-sense anyway).
  12  *  -- set readonly flag for CDs, set removable flag for CF readers
  13  *  -- do inquiry and verify we got a disk and not a tape (for LUN mismatch)
  14  *  -- verify the 13 conditions and do bulk resets
  15  *  -- highmem
  16  *  -- move top_sense and work_bcs into separate allocations (if they survive)
  17  *     for cache purists and esoteric architectures.
  18  *  -- Allocate structure for LUN 0 before the first ub_sync_tur, avoid NULL. ?
  19  *  -- prune comments, they are too volumnous
  20  *  -- Resove XXX's
  21  *  -- CLEAR, CLR2STS, CLRRS seem to be ripe for refactoring.
  22  */
  23 #include <linux/kernel.h>
  24 #include <linux/module.h>
  25 #include <linux/usb.h>
  26 #include <linux/usb_usual.h>
  27 #include <linux/blkdev.h>
  28 #include <linux/timer.h>
  29 #include <linux/scatterlist.h>
  30 #include <scsi/scsi.h>
  31
  32 #define DRV_NAME "ub"
  33
  34 #define UB_MAJOR 180
  35
  36 /*
  37  * The command state machine is the key model for understanding of this driver.
  38  *
  39  * The general rule is that all transitions are done towards the bottom
  40  * of the diagram, thus preventing any loops.
  41  *
  42  * An exception to that is how the STAT state is handled. A counter allows it
  43  * to be re-entered along the path marked with [C].
  44  *
  45  *       +--------+
  46  *       ! INIT   !
  47  *       +--------+
  48  *           !
  49  *        ub_scsi_cmd_start fails ->--------------------------------------\
  50  *           !                                                            !
  51  *           V                                                            !
  52  *       +--------+                                                       !
  53  *       ! CMD    !                                                       !
  54  *       +--------+                                                       !
  55  *           !                                            +--------+      !
  56  *         was -EPIPE -->-------------------------------->! CLEAR  !      !
  57  *           !                                            +--------+      !
  58  *           !                                                !           !
  59  *         was error -->------------------------------------- ! --------->\
  60  *           !                                                !           !
  61  *  /--<-- cmd->dir == NONE ?                                 !           !
  62  *  !        !                                                !           !
  63  *  !        V                                                !           !
  64  *  !    +--------+                                           !           !
  65  *  !    ! DATA   !                                           !           !
  66  *  !    +--------+                                           !           !
  67  *  !        !                           +---------+          !           !
  68  *  !      was -EPIPE -->--------------->! CLR2STS !          !           !
  69  *  !        !                           +---------+          !           !
  70  *  !        !                                !               !           !
  71  *  !        !                              was error -->---- ! --------->\
  72  *  !      was error -->--------------------- ! ------------- ! --------->\
  73  *  !        !                                !               !           !
  74  *  !        V                                !               !           !
  75  *  \--->+--------+                           !               !           !
  76  *       ! STAT   !<--------------------------/               !           !
  77  *  /--->+--------+                                           !           !
  78  *  !        !                                                !           !
  79  * [C]     was -EPIPE -->-----------\                         !           !
  80  *  !        !                      !                         !           !
  81  *  +<---- len == 0                 !                         !           !
  82  *  !        !                      !                         !           !
  83  *  !      was error -->--------------------------------------!---------->\
  84  *  !        !                      !                         !           !
  85  *  +<---- bad CSW                  !                         !           !
  86  *  +<---- bad tag                  !                         !           !
  87  *  !        !                      V                         !           !
  88  *  !        !                 +--------+                     !           !
  89  *  !        !                 ! CLRRS  !                     !           !
  90  *  !        !                 +--------+                     !           !
  91  *  !        !                      !                         !           !
  92  *  \------- ! --------------------[C]--------\               !           !
  93  *           !                                !               !           !
  94  *         cmd->error---\                +--------+           !           !
  95  *           !          +--------------->! SENSE  !<----------/           !
  96  *         STAT_FAIL----/                +--------+                       !
  97  *           !                                !                           V
  98  *           !                                V                      +--------+
  99  *           \--------------------------------\--------------------->! DONE   !
 100  *                                                                   +--------+
 101  */
 102
 103 /*
 104  * This many LUNs per USB device.
 105  * Every one of them takes a host, see UB_MAX_HOSTS.
 106  */
 107 #define UB_MAX_LUNS   9
 108
 109 /*
 110  */
 111
 112 #define UB_PARTS_PER_LUN      8
 113
 114 #define UB_MAX_CDB_SIZE      16         /* Corresponds to Bulk */
 115
 116 #define UB_SENSE_SIZE  18
 117
 118 /*
 119  */
 120
 121 /* command block wrapper */
 122 struct bulk_cb_wrap {
 123         __le32  Signature;              /* contains 'USBC' */
 124         u32     Tag;                    /* unique per command id */
 125         __le32  DataTransferLength;     /* size of data */
 126         u8      Flags;                  /* direction in bit 0 */
 127         u8      Lun;                    /* LUN */
 128         u8      Length;                 /* of of the CDB */
 129         u8      CDB[UB_MAX_CDB_SIZE];   /* max command */
 130 };
 131
 132 #define US_BULK_CB_WRAP_LEN     31
 133 #define US_BULK_CB_SIGN         0x43425355      /*spells out USBC */
 134 #define US_BULK_FLAG_IN         1
 135 #define US_BULK_FLAG_OUT        0
 136
 137 /* command status wrapper */
 138 struct bulk_cs_wrap {
 139         __le32  Signature;              /* should = 'USBS' */
 140         u32     Tag;                    /* same as original command */
 141         __le32  Residue;                /* amount not transferred */
 142         u8      Status;                 /* see below */
 143 };
 144
 145 #define US_BULK_CS_WRAP_LEN     13
 146 #define US_BULK_CS_SIGN         0x53425355      /* spells out 'USBS' */
 147 #define US_BULK_STAT_OK         0
 148 #define US_BULK_STAT_FAIL       1
 149 #define US_BULK_STAT_PHASE      2
 150
 151 /* bulk-only class specific requests */
 152 #define US_BULK_RESET_REQUEST   0xff
 153 #define US_BULK_GET_MAX_LUN     0xfe
 154
 155 /*
 156  */
 157 struct ub_dev;
 158
 159 #define UB_MAX_REQ_SG   9       /* cdrecord requires 32KB and maybe a header */
 160 #define UB_MAX_SECTORS 64
 161
 162 /*
 163  * A second is more than enough for a 32K transfer (UB_MAX_SECTORS)
 164  * even if a webcam hogs the bus, but some devices need time to spin up.
 165  */
 166 #define UB_URB_TIMEOUT  (HZ*2)
 167 #define UB_DATA_TIMEOUT (HZ*5)  /* ZIP does spin-ups in the data phase */
 168 #define UB_STAT_TIMEOUT (HZ*5)  /* Same spinups and eject for a dataless cmd. */
 169 #define UB_CTRL_TIMEOUT (HZ/2)  /* 500ms ought to be enough to clear a stall */
 170
 171 /*
 172  * An instance of a SCSI command in transit.
 173  */
 174 #define UB_DIR_NONE     0
 175 #define UB_DIR_READ     1
 176 #define UB_DIR_ILLEGAL2 2
 177 #define UB_DIR_WRITE    3
 178
 179 #define UB_DIR_CHAR(c)  (((c)==UB_DIR_WRITE)? 'w': \
 180                          (((c)==UB_DIR_READ)? 'r': 'n'))
 181
 182 enum ub_scsi_cmd_state {
 183         UB_CMDST_INIT,                  /* Initial state */
 184         UB_CMDST_CMD,                   /* Command submitted */
 185         UB_CMDST_DATA,                  /* Data phase */
 186         UB_CMDST_CLR2STS,               /* Clearing before requesting status */
 187         UB_CMDST_STAT,                  /* Status phase */
 188         UB_CMDST_CLEAR,                 /* Clearing a stall (halt, actually) */
 189         UB_CMDST_CLRRS,                 /* Clearing before retrying status */
 190         UB_CMDST_SENSE,                 /* Sending Request Sense */
 191         UB_CMDST_DONE                   /* Final state */
 192 };
 193
 194 struct ub_scsi_cmd {
 195         unsigned char cdb[UB_MAX_CDB_SIZE];
 196         unsigned char cdb_len;
 197
 198         unsigned char dir;              /* 0 - none, 1 - read, 3 - write. */
 199         enum ub_scsi_cmd_state state;
 200         unsigned int tag;
 201         struct ub_scsi_cmd *next;
 202
 203         int error;                      /* Return code - valid upon done */
 204         unsigned int act_len;           /* Return size */
 205         unsigned char key, asc, ascq;   /* May be valid if error==-EIO */
 206
 207         int stat_count;                 /* Retries getting status. */
 208         unsigned int timeo;             /* jiffies until rq->timeout changes */
 209
 210         unsigned int len;               /* Requested length */
 211         unsigned int current_sg;
 212         unsigned int nsg;               /* sgv[nsg] */
 213         struct scatterlist sgv[UB_MAX_REQ_SG];
 214
 215         struct ub_lun *lun;
 216         void (*done)(struct ub_dev *, struct ub_scsi_cmd *);
 217         void *back;
 218 };
 219
 220 struct ub_request {
 221         struct request *rq;
 222         unsigned int current_try;
 223         unsigned int nsg;               /* sgv[nsg] */
 224         struct scatterlist sgv[UB_MAX_REQ_SG];
 225 };
 226
 227 /*
 228  */
 229 struct ub_capacity {
 230         unsigned long nsec;             /* Linux size - 512 byte sectors */
 231         unsigned int bsize;             /* Linux hardsect_size */
 232         unsigned int bshift;            /* Shift between 512 and hard sects */
 233 };
 234
 235 /*
 236  * This is a direct take-off from linux/include/completion.h
 237  * The difference is that I do not wait on this thing, just poll.
 238  * When I want to wait (ub_probe), I just use the stock completion.
 239  *
 240  * Note that INIT_COMPLETION takes no lock. It is correct. But why
 241  * in the bloody hell that thing takes struct instead of pointer to struct
 242  * is quite beyond me. I just copied it from the stock completion.
 243  */
 244 struct ub_completion {
 245         unsigned int done;
 246         spinlock_t lock;
 247 };
 248
 249 static inline void ub_init_completion(struct ub_completion *x)
 250 {
 251         x->done = 0;
 252         spin_lock_init(&x->lock);
 253 }
 254
 255 #define UB_INIT_COMPLETION(x)   ((x).done = 0)
 256
 257 static void ub_complete(struct ub_completion *x)
 258 {
 259         unsigned long flags;
 260
 261         spin_lock_irqsave(&x->lock, flags);
 262         x->done++;
 263         spin_unlock_irqrestore(&x->lock, flags);
 264 }
 265
 266 static int ub_is_completed(struct ub_completion *x)
 267 {
 268         unsigned long flags;
 269         int ret;
 270
 271         spin_lock_irqsave(&x->lock, flags);
 272         ret = x->done;
 273         spin_unlock_irqrestore(&x->lock, flags);
 274         return ret;
 275 }
 276
 277 /*
 278  */
 279 struct ub_scsi_cmd_queue {
 280         int qlen, qmax;
 281         struct ub_scsi_cmd *head, *tail;
 282 };
 283
 284 /*
 285  * The block device instance (one per LUN).
 286  */
 287 struct ub_lun {
 288         struct ub_dev *udev;
 289         struct list_head link;
 290         struct gendisk *disk;
 291         int id;                         /* Host index */
 292         int num;                        /* LUN number */
 293         char name[16];
 294
 295         int changed;                    /* Media was changed */
 296         int removable;
 297         int readonly;
 298
 299         struct ub_request urq;
 300
 301         /* Use Ingo's mempool if or when we have more than one command. */
 302         /*
 303          * Currently we never need more than one command for the whole device.
 304          * However, giving every LUN a command is a cheap and automatic way
 305          * to enforce fairness between them.
 306          */
 307         int cmda[1];
 308         struct ub_scsi_cmd cmdv[1];
 309
 310         struct ub_capacity capacity;
 311 };
 312
 313 /*
 314  * The USB device instance.
 315  */
 316 struct ub_dev {
 317         spinlock_t *lock;
 318         atomic_t poison;                /* The USB device is disconnected */
 319         int openc;                      /* protected by ub_lock! */
 320                                         /* kref is too implicit for our taste */
 321         int reset;                      /* Reset is running */
 322         int bad_resid;
 323         unsigned int tagcnt;
 324         char name[12];
 325         struct usb_device *dev;
 326         struct usb_interface *intf;
 327
 328         struct list_head luns;
 329
 330         unsigned int send_bulk_pipe;    /* cached pipe values */
 331         unsigned int recv_bulk_pipe;
 332         unsigned int send_ctrl_pipe;
 333         unsigned int recv_ctrl_pipe;
 334
 335         struct tasklet_struct tasklet;
 336
 337         struct ub_scsi_cmd_queue cmd_queue;
 338         struct ub_scsi_cmd top_rqs_cmd; /* REQUEST SENSE */
 339         unsigned char top_sense[UB_SENSE_SIZE];
 340
 341         struct ub_completion work_done;
 342         struct urb work_urb;
 343         struct timer_list work_timer;
 344         int last_pipe;                  /* What might need clearing */
 345         __le32 signature;               /* Learned signature */
 346         struct bulk_cb_wrap work_bcb;
 347         struct bulk_cs_wrap work_bcs;
 348         struct usb_ctrlrequest work_cr;
 349
 350         struct work_struct reset_work;
 351         wait_queue_head_t reset_wait;
 352 };
 353
 354 /*
 355  */
 356 static void ub_cleanup(struct ub_dev *sc);
 357 static int ub_request_fn_1(struct ub_lun *lun, struct request *rq);
 358 static void ub_cmd_build_block(struct ub_dev *sc, struct ub_lun *lun,
 359     struct ub_scsi_cmd *cmd, struct ub_request *urq);
 360 static void ub_cmd_build_packet(struct ub_dev *sc, struct ub_lun *lun,
 361     struct ub_scsi_cmd *cmd, struct ub_request *urq);
 362 static void ub_rw_cmd_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 363 static void ub_end_rq(struct request *rq, unsigned int status,
 364     unsigned int cmd_len);
 365 static int ub_rw_cmd_retry(struct ub_dev *sc, struct ub_lun *lun,
 366     struct ub_request *urq, struct ub_scsi_cmd *cmd);
 367 static int ub_submit_scsi(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 368 static void ub_urb_complete(struct urb *urb);
 369 static void ub_scsi_action(unsigned long _dev);
 370 static void ub_scsi_dispatch(struct ub_dev *sc);
 371 static void ub_scsi_urb_compl(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 372 static void ub_data_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 373 static void ub_state_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd, int rc);
 374 static int __ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 375 static void ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 376 static void ub_state_stat_counted(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 377 static void ub_state_sense(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 378 static int ub_submit_clear_stall(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
 379     int stalled_pipe);
 380 static void ub_top_sense_done(struct ub_dev *sc, struct ub_scsi_cmd *scmd);
 381 static void ub_reset_enter(struct ub_dev *sc, int try);
 382 static void ub_reset_task(struct work_struct *work);
 383 static int ub_sync_tur(struct ub_dev *sc, struct ub_lun *lun);
 384 static int ub_sync_read_cap(struct ub_dev *sc, struct ub_lun *lun,
 385     struct ub_capacity *ret);
 386 static int ub_sync_reset(struct ub_dev *sc);
 387 static int ub_probe_clear_stall(struct ub_dev *sc, int stalled_pipe);
 388 static int ub_probe_lun(struct ub_dev *sc, int lnum);
 389
 390 /*
 391  */
 392 #ifdef CONFIG_USB_LIBUSUAL
 393
 394 #define ub_usb_ids  usb_storage_usb_ids
 395 #else
 396
 397 static struct usb_device_id ub_usb_ids[] = {
 398         { USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, US_SC_SCSI, US_PR_BULK) },
 399         { }
 400 };
 401
 402 MODULE_DEVICE_TABLE(usb, ub_usb_ids);
 403 #endif /* CONFIG_USB_LIBUSUAL */
 404
 405 /*
 406  * Find me a way to identify "next free minor" for add_disk(),
 407  * and the array disappears the next day. However, the number of
 408  * hosts has something to do with the naming and /proc/partitions.
 409  * This has to be thought out in detail before changing.
 410  * If UB_MAX_HOST was 1000, we'd use a bitmap. Or a better data structure.
 411  */
 412 #define UB_MAX_HOSTS  26
 413 static char ub_hostv[UB_MAX_HOSTS];
 414
 415 #define UB_QLOCK_NUM 5
 416 static spinlock_t ub_qlockv[UB_QLOCK_NUM];
 417 static int ub_qlock_next = 0;
 418
 419 static DEFINE_SPINLOCK(ub_lock);        /* Locks globals and ->openc */
 420
 421 /*
 422  * The id allocator.
 423  *
 424  * This also stores the host for indexing by minor, which is somewhat dirty.
 425  */
 426 static int ub_id_get(void)
 427 {
 428         unsigned long flags;
 429         int i;
 430
 431         spin_lock_irqsave(&ub_lock, flags);
 432         for (i = 0; i < UB_MAX_HOSTS; i++) {
 433                 if (ub_hostv[i] == 0) {
 434                         ub_hostv[i] = 1;
 435                         spin_unlock_irqrestore(&ub_lock, flags);
 436                         return i;
 437                 }
 438         }
 439         spin_unlock_irqrestore(&ub_lock, flags);
 440         return -1;
 441 }
 442
 443 static void ub_id_put(int id)
 444 {
 445         unsigned long flags;
 446
 447         if (id < 0 || id >= UB_MAX_HOSTS) {
 448                 printk(KERN_ERR DRV_NAME ": bad host ID %d\n", id);
 449                 return;
 450         }
 451
 452         spin_lock_irqsave(&ub_lock, flags);
 453         if (ub_hostv[id] == 0) {
 454                 spin_unlock_irqrestore(&ub_lock, flags);
 455                 printk(KERN_ERR DRV_NAME ": freeing free host ID %d\n", id);
 456                 return;
 457         }
 458         ub_hostv[id] = 0;
 459         spin_unlock_irqrestore(&ub_lock, flags);
 460 }
 461
 462 /*
 463  * This is necessitated by the fact that blk_cleanup_queue does not
 464  * necesserily destroy the queue. Instead, it may merely decrease q->refcnt.
 465  * Since our blk_init_queue() passes a spinlock common with ub_dev,
 466  * we have life time issues when ub_cleanup frees ub_dev.
 467  */
 468 static spinlock_t *ub_next_lock(void)
 469 {
 470         unsigned long flags;
 471         spinlock_t *ret;
 472
 473         spin_lock_irqsave(&ub_lock, flags);
 474         ret = &ub_qlockv[ub_qlock_next];
 475         ub_qlock_next = (ub_qlock_next + 1) % UB_QLOCK_NUM;
 476         spin_unlock_irqrestore(&ub_lock, flags);
 477         return ret;
 478 }
 479
 480 /*
 481  * Downcount for deallocation. This rides on two assumptions:
 482  *  - once something is poisoned, its refcount cannot grow
 483  *  - opens cannot happen at this time (del_gendisk was done)
 484  * If the above is true, we can drop the lock, which we need for
 485  * blk_cleanup_queue(): the silly thing may attempt to sleep.
 486  * [Actually, it never needs to sleep for us, but it calls might_sleep()]
 487  */
 488 static void ub_put(struct ub_dev *sc)
 489 {
 490         unsigned long flags;
 491
 492         spin_lock_irqsave(&ub_lock, flags);
 493         --sc->openc;
 494         if (sc->openc == 0 && atomic_read(&sc->poison)) {
 495                 spin_unlock_irqrestore(&ub_lock, flags);
 496                 ub_cleanup(sc);
 497         } else {
 498                 spin_unlock_irqrestore(&ub_lock, flags);
 499         }
 500 }
 501
 502 /*
 503  * Final cleanup and deallocation.
 504  */
 505 static void ub_cleanup(struct ub_dev *sc)
 506 {
 507         struct list_head *p;
 508         struct ub_lun *lun;
 509         struct request_queue *q;
 510
 511         while (!list_empty(&sc->luns)) {
 512                 p = sc->luns.next;
 513                 lun = list_entry(p, struct ub_lun, link);
 514                 list_del(p);
 515
 516                 /* I don't think queue can be NULL. But... Stolen from sx8.c */
 517                 if ((q = lun->disk->queue) != NULL)
 518                         blk_cleanup_queue(q);
 519                 /*
 520                  * If we zero disk->private_data BEFORE put_disk, we have
 521                  * to check for NULL all over the place in open, release,
 522                  * check_media and revalidate, because the block level
 523                  * semaphore is well inside the put_disk.
 524                  * But we cannot zero after the call, because *disk is gone.
 525                  * The sd.c is blatantly racy in this area.
 526                  */
 527                 /* disk->private_data = NULL; */
 528                 put_disk(lun->disk);
 529                 lun->disk = NULL;
 530
 531                 ub_id_put(lun->id);
 532                 kfree(lun);
 533         }
 534
 535         usb_set_intfdata(sc->intf, NULL);
 536         usb_put_intf(sc->intf);
 537         usb_put_dev(sc->dev);
 538         kfree(sc);
 539 }
 540
 541 /*
 542  * The "command allocator".
 543  */
 544 static struct ub_scsi_cmd *ub_get_cmd(struct ub_lun *lun)
 545 {
 546         struct ub_scsi_cmd *ret;
 547
 548         if (lun->cmda[0])
 549                 return NULL;
 550         ret = &lun->cmdv[0];
 551         lun->cmda[0] = 1;
 552         return ret;
 553 }
 554
 555 static void ub_put_cmd(struct ub_lun *lun, struct ub_scsi_cmd *cmd)
 556 {
 557         if (cmd != &lun->cmdv[0]) {
 558                 printk(KERN_WARNING "%s: releasing a foreign cmd %p\n",
 559                     lun->name, cmd);
 560                 return;
 561         }
 562         if (!lun->cmda[0]) {
 563                 printk(KERN_WARNING "%s: releasing a free cmd\n", lun->name);
 564                 return;
 565         }
 566         lun->cmda[0] = 0;
 567 }
 568
 569 /*
 570  * The command queue.
 571  */
 572 static void ub_cmdq_add(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 573 {
 574         struct ub_scsi_cmd_queue *t = &sc->cmd_queue;
 575
 576         if (t->qlen++ == 0) {
 577                 t->head = cmd;
 578                 t->tail = cmd;
 579         } else {
 580                 t->tail->next = cmd;
 581                 t->tail = cmd;
 582         }
 583
 584         if (t->qlen > t->qmax)
 585                 t->qmax = t->qlen;
 586 }
 587
 588 static void ub_cmdq_insert(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 589 {
 590         struct ub_scsi_cmd_queue *t = &sc->cmd_queue;
 591
 592         if (t->qlen++ == 0) {
 593                 t->head = cmd;
 594                 t->tail = cmd;
 595         } else {
 596                 cmd->next = t->head;
 597                 t->head = cmd;
 598         }
 599
 600         if (t->qlen > t->qmax)
 601                 t->qmax = t->qlen;
 602 }
 603
 604 static struct ub_scsi_cmd *ub_cmdq_pop(struct ub_dev *sc)
 605 {
 606         struct ub_scsi_cmd_queue *t = &sc->cmd_queue;
 607         struct ub_scsi_cmd *cmd;
 608
 609         if (t->qlen == 0)
 610                 return NULL;
 611         if (--t->qlen == 0)
 612                 t->tail = NULL;
 613         cmd = t->head;
 614         t->head = cmd->next;
 615         cmd->next = NULL;
 616         return cmd;
 617 }
 618
 619 #define ub_cmdq_peek(sc)  ((sc)->cmd_queue.head)
 620
 621 /*
 622  * The request function is our main entry point
 623  */
 624
 625 static void ub_request_fn(struct request_queue *q)
 626 {
 627         struct ub_lun *lun = q->queuedata;
 628         struct request *rq;
 629
 630         while ((rq = elv_next_request(q)) != NULL) {
 631                 if (ub_request_fn_1(lun, rq) != 0) {
 632                         blk_stop_queue(q);
 633                         break;
 634                 }
 635         }
 636 }
 637
 638 static int ub_request_fn_1(struct ub_lun *lun, struct request *rq)
 639 {
 640         struct ub_dev *sc = lun->udev;
 641         struct ub_scsi_cmd *cmd;
 642         struct ub_request *urq;
 643         int n_elem;
 644
 645         if (atomic_read(&sc->poison)) {
 646                 blkdev_dequeue_request(rq);
 647                 ub_end_rq(rq, DID_NO_CONNECT << 16, blk_rq_bytes(rq));
 648                 return 0;
 649         }
 650
 651         if (lun->changed && !blk_pc_request(rq)) {
 652                 blkdev_dequeue_request(rq);
 653                 ub_end_rq(rq, SAM_STAT_CHECK_CONDITION, blk_rq_bytes(rq));
 654                 return 0;
 655         }
 656
 657         if (lun->urq.rq != NULL)
 658                 return -1;
 659         if ((cmd = ub_get_cmd(lun)) == NULL)
 660                 return -1;
 661         memset(cmd, 0, sizeof(struct ub_scsi_cmd));
 662
 663         blkdev_dequeue_request(rq);
 664
 665         urq = &lun->urq;
 666         memset(urq, 0, sizeof(struct ub_request));
 667         urq->rq = rq;
 668
 669         /*
 670          * get scatterlist from block layer
 671          */
 672         sg_init_table(&urq->sgv[0], UB_MAX_REQ_SG);
 673         n_elem = blk_rq_map_sg(lun->disk->queue, rq, &urq->sgv[0]);
 674         if (n_elem < 0) {
 675                 /* Impossible, because blk_rq_map_sg should not hit ENOMEM. */
 676                 printk(KERN_INFO "%s: failed request map (%d)\n",
 677                     lun->name, n_elem);
 678                 goto drop;
 679         }
 680         if (n_elem > UB_MAX_REQ_SG) {   /* Paranoia */
 681                 printk(KERN_WARNING "%s: request with %d segments\n",
 682                     lun->name, n_elem);
 683                 goto drop;
 684         }
 685         urq->nsg = n_elem;
 686
 687         if (blk_pc_request(rq)) {
 688                 ub_cmd_build_packet(sc, lun, cmd, urq);
 689         } else {
 690                 ub_cmd_build_block(sc, lun, cmd, urq);
 691         }
 692         cmd->state = UB_CMDST_INIT;
 693         cmd->lun = lun;
 694         cmd->done = ub_rw_cmd_done;
 695         cmd->back = urq;
 696
 697         cmd->tag = sc->tagcnt++;
 698         if (ub_submit_scsi(sc, cmd) != 0)
 699                 goto drop;
 700
 701         return 0;
 702
 703 drop:
 704         ub_put_cmd(lun, cmd);
 705         ub_end_rq(rq, DID_ERROR << 16, blk_rq_bytes(rq));
 706         return 0;
 707 }
 708
 709 static void ub_cmd_build_block(struct ub_dev *sc, struct ub_lun *lun,
 710     struct ub_scsi_cmd *cmd, struct ub_request *urq)
 711 {
 712         struct request *rq = urq->rq;
 713         unsigned int block, nblks;
 714
 715         if (rq_data_dir(rq) == WRITE)
 716                 cmd->dir = UB_DIR_WRITE;
 717         else
 718                 cmd->dir = UB_DIR_READ;
 719
 720         cmd->nsg = urq->nsg;
 721         memcpy(cmd->sgv, urq->sgv, sizeof(struct scatterlist) * cmd->nsg);
 722
 723         /*
 724          * build the command
 725          *
 726          * The call to blk_queue_hardsect_size() guarantees that request
 727          * is aligned, but it is given in terms of 512 byte units, always.
 728          */
 729         block = rq->sector >> lun->capacity.bshift;
 730         nblks = rq->nr_sectors >> lun->capacity.bshift;
 731
 732         cmd->cdb[0] = (cmd->dir == UB_DIR_READ)? READ_10: WRITE_10;
 733         /* 10-byte uses 4 bytes of LBA: 2147483648KB, 2097152MB, 2048GB */
 734         cmd->cdb[2] = block >> 24;
 735         cmd->cdb[3] = block >> 16;
 736         cmd->cdb[4] = block >> 8;
 737         cmd->cdb[5] = block;
 738         cmd->cdb[7] = nblks >> 8;
 739         cmd->cdb[8] = nblks;
 740         cmd->cdb_len = 10;
 741
 742         cmd->len = rq->nr_sectors * 512;
 743 }
 744
 745 static void ub_cmd_build_packet(struct ub_dev *sc, struct ub_lun *lun,
 746     struct ub_scsi_cmd *cmd, struct ub_request *urq)
 747 {
 748         struct request *rq = urq->rq;
 749
 750         if (rq->data_len == 0) {
 751                 cmd->dir = UB_DIR_NONE;
 752         } else {
 753                 if (rq_data_dir(rq) == WRITE)
 754                         cmd->dir = UB_DIR_WRITE;
 755                 else
 756                         cmd->dir = UB_DIR_READ;
 757         }
 758
 759         cmd->nsg = urq->nsg;
 760         memcpy(cmd->sgv, urq->sgv, sizeof(struct scatterlist) * cmd->nsg);
 761
 762         memcpy(&cmd->cdb, rq->cmd, rq->cmd_len);
 763         cmd->cdb_len = rq->cmd_len;
 764
 765         cmd->len = rq->data_len;
 766
 767         /*
 768          * To reapply this to every URB is not as incorrect as it looks.
 769          * In return, we avoid any complicated tracking calculations.
 770          */
 771         cmd->timeo = rq->timeout;
 772 }
 773
 774 static void ub_rw_cmd_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 775 {
 776         struct ub_lun *lun = cmd->lun;
 777         struct ub_request *urq = cmd->back;
 778         struct request *rq;
 779         unsigned int scsi_status;
 780         unsigned int cmd_len;
 781
 782         rq = urq->rq;
 783
 784         if (cmd->error == 0) {
 785                 if (blk_pc_request(rq)) {
 786                         if (cmd->act_len >= rq->data_len)
 787                                 rq->data_len = 0;
 788                         else
 789                                 rq->data_len -= cmd->act_len;
 790                         scsi_status = 0;
 791                 } else {
 792                         if (cmd->act_len != cmd->len) {
 793                                 scsi_status = SAM_STAT_CHECK_CONDITION;
 794                         } else {
 795                                 scsi_status = 0;
 796                         }
 797                 }
 798         } else {
 799                 if (blk_pc_request(rq)) {
 800                         /* UB_SENSE_SIZE is smaller than SCSI_SENSE_BUFFERSIZE */
 801                         memcpy(rq->sense, sc->top_sense, UB_SENSE_SIZE);
 802                         rq->sense_len = UB_SENSE_SIZE;
 803                         if (sc->top_sense[0] != 0)
 804                                 scsi_status = SAM_STAT_CHECK_CONDITION;
 805                         else
 806                                 scsi_status = DID_ERROR << 16;
 807                 } else {
 808                         if (cmd->error == -EIO &&
 809                             (cmd->key == 0 ||
 810                              cmd->key == MEDIUM_ERROR ||
 811                              cmd->key == UNIT_ATTENTION)) {
 812                                 if (ub_rw_cmd_retry(sc, lun, urq, cmd) == 0)
 813                                         return;
 814                         }
 815                         scsi_status = SAM_STAT_CHECK_CONDITION;
 816                 }
 817         }
 818
 819         urq->rq = NULL;
 820
 821         cmd_len = cmd->len;
 822         ub_put_cmd(lun, cmd);
 823         ub_end_rq(rq, scsi_status, cmd_len);
 824         blk_start_queue(lun->disk->queue);
 825 }
 826
 827 static void ub_end_rq(struct request *rq, unsigned int scsi_status,
 828     unsigned int cmd_len)
 829 {
 830         int error;
 831         long rqlen;
 832
 833         if (scsi_status == 0) {
 834                 error = 0;
 835         } else {
 836                 error = -EIO;
 837                 rq->errors = scsi_status;
 838         }
 839         rqlen = blk_rq_bytes(rq);    /* Oddly enough, this is the residue. */
 840         if (__blk_end_request(rq, error, cmd_len)) {
 841                 printk(KERN_WARNING DRV_NAME
 842                     ": __blk_end_request blew, %s-cmd total %u rqlen %ld\n",
 843                     blk_pc_request(rq)? "pc": "fs", cmd_len, rqlen);
 844         }
 845 }
 846
 847 static int ub_rw_cmd_retry(struct ub_dev *sc, struct ub_lun *lun,
 848     struct ub_request *urq, struct ub_scsi_cmd *cmd)
 849 {
 850
 851         if (atomic_read(&sc->poison))
 852                 return -ENXIO;
 853
 854         ub_reset_enter(sc, urq->current_try);
 855
 856         if (urq->current_try >= 3)
 857                 return -EIO;
 858         urq->current_try++;
 859
 860         /* Remove this if anyone complains of flooding. */
 861         printk(KERN_DEBUG "%s: dir %c len/act %d/%d "
 862             "[sense %x %02x %02x] retry %d\n",
 863             sc->name, UB_DIR_CHAR(cmd->dir), cmd->len, cmd->act_len,
 864             cmd->key, cmd->asc, cmd->ascq, urq->current_try);
 865
 866         memset(cmd, 0, sizeof(struct ub_scsi_cmd));
 867         ub_cmd_build_block(sc, lun, cmd, urq);
 868
 869         cmd->state = UB_CMDST_INIT;
 870         cmd->lun = lun;
 871         cmd->done = ub_rw_cmd_done;
 872         cmd->back = urq;
 873
 874         cmd->tag = sc->tagcnt++;
 875
 876 #if 0 /* Wasteful */
 877         return ub_submit_scsi(sc, cmd);
 878 #else
 879         ub_cmdq_add(sc, cmd);
 880         return 0;
 881 #endif
 882 }
 883
 884 /*
 885  * Submit a regular SCSI operation (not an auto-sense).
 886  *
 887  * The Iron Law of Good Submit Routine is:
 888  * Zero return - callback is done, Nonzero return - callback is not done.
 889  * No exceptions.
 890  *
 891  * Host is assumed locked.
 892  */
 893 static int ub_submit_scsi(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 894 {
 895
 896         if (cmd->state != UB_CMDST_INIT ||
 897             (cmd->dir != UB_DIR_NONE && cmd->len == 0)) {
 898                 return -EINVAL;
 899         }
 900
 901         ub_cmdq_add(sc, cmd);
 902         /*
 903          * We can call ub_scsi_dispatch(sc) right away here, but it's a little
 904          * safer to jump to a tasklet, in case upper layers do something silly.
 905          */
 906         tasklet_schedule(&sc->tasklet);
 907         return 0;
 908 }
 909
 910 /*
 911  * Submit the first URB for the queued command.
 912  * This function does not deal with queueing in any way.
 913  */
 914 static int ub_scsi_cmd_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 915 {
 916         struct bulk_cb_wrap *bcb;
 917         int rc;
 918
 919         bcb = &sc->work_bcb;
 920
 921         /*
 922          * ``If the allocation length is eighteen or greater, and a device
 923          * server returns less than eithteen bytes of data, the application
 924          * client should assume that the bytes not transferred would have been
 925          * zeroes had the device server returned those bytes.''
 926          *
 927          * We zero sense for all commands so that when a packet request
 928          * fails it does not return a stale sense.
 929          */
 930         memset(&sc->top_sense, 0, UB_SENSE_SIZE);
 931
 932         /* set up the command wrapper */
 933         bcb->Signature = cpu_to_le32(US_BULK_CB_SIGN);
 934         bcb->Tag = cmd->tag;            /* Endianness is not important */
 935         bcb->DataTransferLength = cpu_to_le32(cmd->len);
 936         bcb->Flags = (cmd->dir == UB_DIR_READ) ? 0x80 : 0;
 937         bcb->Lun = (cmd->lun != NULL) ? cmd->lun->num : 0;
 938         bcb->Length = cmd->cdb_len;
 939
 940         /* copy the command payload */
 941         memcpy(bcb->CDB, cmd->cdb, UB_MAX_CDB_SIZE);
 942
 943         UB_INIT_COMPLETION(sc->work_done);
 944
 945         sc->last_pipe = sc->send_bulk_pipe;
 946         usb_fill_bulk_urb(&sc->work_urb, sc->dev, sc->send_bulk_pipe,
 947             bcb, US_BULK_CB_WRAP_LEN, ub_urb_complete, sc);
 948
 949         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
 950                 /* XXX Clear stalls */
 951                 ub_complete(&sc->work_done);
 952                 return rc;
 953         }
 954
 955         sc->work_timer.expires = jiffies + UB_URB_TIMEOUT;
 956         add_timer(&sc->work_timer);
 957
 958         cmd->state = UB_CMDST_CMD;
 959         return 0;
 960 }
 961
 962 /*
 963  * Timeout handler.
 964  */
 965 static void ub_urb_timeout(unsigned long arg)
 966 {
 967         struct ub_dev *sc = (struct ub_dev *) arg;
 968         unsigned long flags;
 969
 970         spin_lock_irqsave(sc->lock, flags);
 971         if (!ub_is_completed(&sc->work_done))
 972                 usb_unlink_urb(&sc->work_urb);
 973         spin_unlock_irqrestore(sc->lock, flags);
 974 }
 975
 976 /*
 977  * Completion routine for the work URB.
 978  *
 979  * This can be called directly from usb_submit_urb (while we have
 980  * the sc->lock taken) and from an interrupt (while we do NOT have
 981  * the sc->lock taken). Therefore, bounce this off to a tasklet.
 982  */
 983 static void ub_urb_complete(struct urb *urb)
 984 {
 985         struct ub_dev *sc = urb->context;
 986
 987         ub_complete(&sc->work_done);
 988         tasklet_schedule(&sc->tasklet);
 989 }
 990
 991 static void ub_scsi_action(unsigned long _dev)
 992 {
 993         struct ub_dev *sc = (struct ub_dev *) _dev;
 994         unsigned long flags;
 995
 996         spin_lock_irqsave(sc->lock, flags);
 997         ub_scsi_dispatch(sc);
 998         spin_unlock_irqrestore(sc->lock, flags);
 999 }
1000
1001 static void ub_scsi_dispatch(struct ub_dev *sc)
1002 {
1003         struct ub_scsi_cmd *cmd;
1004         int rc;
1005
1006         while (!sc->reset && (cmd = ub_cmdq_peek(sc)) != NULL) {
1007                 if (cmd->state == UB_CMDST_DONE) {
1008                         ub_cmdq_pop(sc);
1009                         (*cmd->done)(sc, cmd);
1010                 } else if (cmd->state == UB_CMDST_INIT) {
1011                         if ((rc = ub_scsi_cmd_start(sc, cmd)) == 0)
1012                                 break;
1013                         cmd->error = rc;
1014                         cmd->state = UB_CMDST_DONE;
1015                 } else {
1016                         if (!ub_is_completed(&sc->work_done))
1017                                 break;
1018                         del_timer(&sc->work_timer);
1019                         ub_scsi_urb_compl(sc, cmd);
1020                 }
1021         }
1022 }
1023
1024 static void ub_scsi_urb_compl(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1025 {
1026         struct urb *urb = &sc->work_urb;
1027         struct bulk_cs_wrap *bcs;
1028         int endp;
1029         int len;
1030         int rc;
1031
1032         if (atomic_read(&sc->poison)) {
1033                 ub_state_done(sc, cmd, -ENODEV);
1034                 return;
1035         }
1036
1037         endp = usb_pipeendpoint(sc->last_pipe);
1038         if (usb_pipein(sc->last_pipe))
1039                 endp |= USB_DIR_IN;
1040
1041         if (cmd->state == UB_CMDST_CLEAR) {
1042                 if (urb->status == -EPIPE) {
1043                         /*
1044                          * STALL while clearning STALL.
1045                          * The control pipe clears itself - nothing to do.
1046                          */
1047                         printk(KERN_NOTICE "%s: stall on control pipe\n",
1048                             sc->name);
1049                         goto Bad_End;
1050                 }
1051
1052                 /*
1053                  * We ignore the result for the halt clear.
1054                  */
1055
1056                 usb_reset_endpoint(sc->dev, endp);
1057
1058                 ub_state_sense(sc, cmd);
1059
1060         } else if (cmd->state == UB_CMDST_CLR2STS) {
1061                 if (urb->status == -EPIPE) {
1062                         printk(KERN_NOTICE "%s: stall on control pipe\n",
1063                             sc->name);
1064                         goto Bad_End;
1065                 }
1066
1067                 /*
1068                  * We ignore the result for the halt clear.
1069                  */
1070
1071                 usb_reset_endpoint(sc->dev, endp);
1072
1073                 ub_state_stat(sc, cmd);
1074
1075         } else if (cmd->state == UB_CMDST_CLRRS) {
1076                 if (urb->status == -EPIPE) {
1077                         printk(KERN_NOTICE "%s: stall on control pipe\n",
1078                             sc->name);
1079                         goto Bad_End;
1080                 }
1081
1082                 /*
1083                  * We ignore the result for the halt clear.
1084                  */
1085
1086                 usb_reset_endpoint(sc->dev, endp);
1087
1088                 ub_state_stat_counted(sc, cmd);
1089
1090         } else if (cmd->state == UB_CMDST_CMD) {
1091                 switch (urb->status) {
1092                 case 0:
1093                         break;
1094                 case -EOVERFLOW:
1095                         goto Bad_End;
1096                 case -EPIPE:
1097                         rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
1098                         if (rc != 0) {
1099                                 printk(KERN_NOTICE "%s: "
1100                                     "unable to submit clear (%d)\n",
1101                                     sc->name, rc);
1102                                 /*
1103                                  * This is typically ENOMEM or some other such shit.
1104                                  * Retrying is pointless. Just do Bad End on it...
1105                                  */
1106                                 ub_state_done(sc, cmd, rc);
1107                                 return;
1108                         }
1109                         cmd->state = UB_CMDST_CLEAR;
1110                         return;
1111                 case -ESHUTDOWN:        /* unplug */
1112                 case -EILSEQ:           /* unplug timeout on uhci */
1113                         ub_state_done(sc, cmd, -ENODEV);
1114                         return;
1115                 default:
1116                         goto Bad_End;
1117                 }
1118                 if (urb->actual_length != US_BULK_CB_WRAP_LEN) {
1119                         goto Bad_End;
1120                 }
1121
1122                 if (cmd->dir == UB_DIR_NONE || cmd->nsg < 1) {
1123                         ub_state_stat(sc, cmd);
1124                         return;
1125                 }
1126
1127                 // udelay(125);         // usb-storage has this
1128                 ub_data_start(sc, cmd);
1129
1130         } else if (cmd->state == UB_CMDST_DATA) {
1131                 if (urb->status == -EPIPE) {
1132                         rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
1133                         if (rc != 0) {
1134                                 printk(KERN_NOTICE "%s: "
1135                                     "unable to submit clear (%d)\n",
1136                                     sc->name, rc);
1137                                 ub_state_done(sc, cmd, rc);
1138                                 return;
1139                         }
1140                         cmd->state = UB_CMDST_CLR2STS;
1141                         return;
1142                 }
1143                 if (urb->status == -EOVERFLOW) {
1144                         /*
1145                          * A babble? Failure, but we must transfer CSW now.
1146                          */
1147                         cmd->error = -EOVERFLOW;        /* A cheap trick... */
1148                         ub_state_stat(sc, cmd);
1149                         return;
1150                 }
1151
1152                 if (cmd->dir == UB_DIR_WRITE) {
1153                         /*
1154                          * Do not continue writes in case of a failure.
1155                          * Doing so would cause sectors to be mixed up,
1156                          * which is worse than sectors lost.
1157                          *
1158                          * We must try to read the CSW, or many devices
1159                          * get confused.
1160                          */
1161                         len = urb->actual_length;
1162                         if (urb->status != 0 ||
1163                             len != cmd->sgv[cmd->current_sg].length) {
1164                                 cmd->act_len += len;
1165
1166                                 cmd->error = -EIO;
1167                                 ub_state_stat(sc, cmd);
1168                                 return;
1169                         }
1170
1171                 } else {
1172                         /*
1173                          * If an error occurs on read, we record it, and
1174                          * continue to fetch data in order to avoid bubble.
1175                          *
1176                          * As a small shortcut, we stop if we detect that
1177                          * a CSW mixed into data.
1178                          */
1179                         if (urb->status != 0)
1180                                 cmd->error = -EIO;
1181
1182                         len = urb->actual_length;
1183                         if (urb->status != 0 ||
1184                             len != cmd->sgv[cmd->current_sg].length) {
1185                                 if ((len & 0x1FF) == US_BULK_CS_WRAP_LEN)
1186                                         goto Bad_End;
1187                         }
1188                 }
1189
1190                 cmd->act_len += urb->actual_length;
1191
1192                 if (++cmd->current_sg < cmd->nsg) {
1193                         ub_data_start(sc, cmd);
1194                         return;
1195                 }
1196                 ub_state_stat(sc, cmd);
1197
1198         } else if (cmd->state == UB_CMDST_STAT) {
1199                 if (urb->status == -EPIPE) {
1200                         rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
1201                         if (rc != 0) {
1202                                 printk(KERN_NOTICE "%s: "
1203                                     "unable to submit clear (%d)\n",
1204                                     sc->name, rc);
1205                                 ub_state_done(sc, cmd, rc);
1206                                 return;
1207                         }
1208
1209                         /*
1210                          * Having a stall when getting CSW is an error, so
1211                          * make sure uppper levels are not oblivious to it.
1212                          */
1213                         cmd->error = -EIO;              /* A cheap trick... */
1214
1215                         cmd->state = UB_CMDST_CLRRS;
1216                         return;
1217                 }
1218
1219                 /* Catch everything, including -EOVERFLOW and other nasties. */
1220                 if (urb->status != 0)
1221                         goto Bad_End;
1222
1223                 if (urb->actual_length == 0) {
1224                         ub_state_stat_counted(sc, cmd);
1225                         return;
1226                 }
1227
1228                 /*
1229                  * Check the returned Bulk protocol status.
1230                  * The status block has to be validated first.
1231                  */
1232
1233                 bcs = &sc->work_bcs;
1234
1235                 if (sc->signature == cpu_to_le32(0)) {
1236                         /*
1237                          * This is the first reply, so do not perform the check.
1238                          * Instead, remember the signature the device uses
1239                          * for future checks. But do not allow a nul.
1240                          */
1241                         sc->signature = bcs->Signature;
1242                         if (sc->signature == cpu_to_le32(0)) {
1243                                 ub_state_stat_counted(sc, cmd);
1244                                 return;
1245                         }
1246                 } else {
1247                         if (bcs->Signature != sc->signature) {
1248                                 ub_state_stat_counted(sc, cmd);
1249                                 return;
1250                         }
1251                 }
1252
1253                 if (bcs->Tag != cmd->tag) {
1254                         /*
1255                          * This usually happens when we disagree with the
1256                          * device's microcode about something. For instance,
1257                          * a few of them throw this after timeouts. They buffer
1258                          * commands and reply at commands we timed out before.
1259                          * Without flushing these replies we loop forever.
1260                          */
1261                         ub_state_stat_counted(sc, cmd);
1262                         return;
1263                 }
1264
1265                 if (!sc->bad_resid) {
1266                         len = le32_to_cpu(bcs->Residue);
1267                         if (len != cmd->len - cmd->act_len) {
1268                                 /*
1269                                  * Only start ignoring if this cmd ended well.
1270                                  */
1271                                 if (cmd->len == cmd->act_len) {
1272                                         printk(KERN_NOTICE "%s: "
1273                                             "bad residual %d of %d, ignoring\n",
1274                                             sc->name, len, cmd->len);
1275                                         sc->bad_resid = 1;
1276                                 }
1277                         }
1278                 }
1279
1280                 switch (bcs->Status) {
1281                 case US_BULK_STAT_OK:
1282                         break;
1283                 case US_BULK_STAT_FAIL:
1284                         ub_state_sense(sc, cmd);
1285                         return;
1286                 case US_BULK_STAT_PHASE:
1287                         goto Bad_End;
1288                 default:
1289                         printk(KERN_INFO "%s: unknown CSW status 0x%x\n",
1290                             sc->name, bcs->Status);
1291                         ub_state_done(sc, cmd, -EINVAL);
1292                         return;
1293                 }
1294
1295                 /* Not zeroing error to preserve a babble indicator */
1296                 if (cmd->error != 0) {
1297                         ub_state_sense(sc, cmd);
1298                         return;
1299                 }
1300                 cmd->state = UB_CMDST_DONE;
1301                 ub_cmdq_pop(sc);
1302                 (*cmd->done)(sc, cmd);
1303
1304         } else if (cmd->state == UB_CMDST_SENSE) {
1305                 ub_state_done(sc, cmd, -EIO);
1306
1307         } else {
1308                 printk(KERN_WARNING "%s: wrong command state %d\n",
1309                     sc->name, cmd->state);
1310                 ub_state_done(sc, cmd, -EINVAL);
1311                 return;
1312         }
1313         return;
1314
1315 Bad_End: /* Little Excel is dead */
1316         ub_state_done(sc, cmd, -EIO);
1317 }
1318
1319 /*
1320  * Factorization helper for the command state machine:
1321  * Initiate a data segment transfer.
1322  */
1323 static void ub_data_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1324 {
1325         struct scatterlist *sg = &cmd->sgv[cmd->current_sg];
1326         int pipe;
1327         int rc;
1328
1329         UB_INIT_COMPLETION(sc->work_done);
1330
1331         if (cmd->dir == UB_DIR_READ)
1332                 pipe = sc->recv_bulk_pipe;
1333         else
1334                 pipe = sc->send_bulk_pipe;
1335         sc->last_pipe = pipe;
1336         usb_fill_bulk_urb(&sc->work_urb, sc->dev, pipe, sg_virt(sg),
1337             sg->length, ub_urb_complete, sc);
1338
1339         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
1340                 /* XXX Clear stalls */
1341                 ub_complete(&sc->work_done);
1342                 ub_state_done(sc, cmd, rc);
1343                 return;
1344         }
1345
1346         if (cmd->timeo)
1347                 sc->work_timer.expires = jiffies + cmd->timeo;
1348         else
1349                 sc->work_timer.expires = jiffies + UB_DATA_TIMEOUT;
1350         add_timer(&sc->work_timer);
1351
1352         cmd->state = UB_CMDST_DATA;
1353 }
1354
1355 /*
1356  * Factorization helper for the command state machine:
1357  * Finish the command.
1358  */
1359 static void ub_state_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd, int rc)
1360 {
1361
1362         cmd->error = rc;
1363         cmd->state = UB_CMDST_DONE;
1364         ub_cmdq_pop(sc);
1365         (*cmd->done)(sc, cmd);
1366 }
1367
1368 /*
1369  * Factorization helper for the command state machine:
1370  * Submit a CSW read.
1371  */
1372 static int __ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1373 {
1374         int rc;
1375
1376         UB_INIT_COMPLETION(sc->work_done);
1377
1378         sc->last_pipe = sc->recv_bulk_pipe;
1379         usb_fill_bulk_urb(&sc->work_urb, sc->dev, sc->recv_bulk_pipe,
1380             &sc->work_bcs, US_BULK_CS_WRAP_LEN, ub_urb_complete, sc);
1381
1382         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
1383                 /* XXX Clear stalls */
1384                 ub_complete(&sc->work_done);
1385                 ub_state_done(sc, cmd, rc);
1386                 return -1;
1387         }
1388
1389         if (cmd->timeo)
1390                 sc->work_timer.expires = jiffies + cmd->timeo;
1391         else
1392                 sc->work_timer.expires = jiffies + UB_STAT_TIMEOUT;
1393         add_timer(&sc->work_timer);
1394         return 0;
1395 }
1396
1397 /*
1398  * Factorization helper for the command state machine:
1399  * Submit a CSW read and go to STAT state.
1400  */
1401 static void ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1402 {
1403
1404         if (__ub_state_stat(sc, cmd) != 0)
1405                 return;
1406
1407         cmd->stat_count = 0;
1408         cmd->state = UB_CMDST_STAT;
1409 }
1410
1411 /*
1412  * Factorization helper for the command state machine:
1413  * Submit a CSW read and go to STAT state with counter (along [C] path).
1414  */
1415 static void ub_state_stat_counted(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1416 {
1417
1418         if (++cmd->stat_count >= 4) {
1419                 ub_state_sense(sc, cmd);
1420                 return;
1421         }
1422
1423         if (__ub_state_stat(sc, cmd) != 0)
1424                 return;
1425
1426         cmd->state = UB_CMDST_STAT;
1427 }
1428
1429 /*
1430  * Factorization helper for the command state machine:
1431  * Submit a REQUEST SENSE and go to SENSE state.
1432  */
1433 static void ub_state_sense(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1434 {
1435         struct ub_scsi_cmd *scmd;
1436         struct scatterlist *sg;
1437         int rc;
1438
1439         if (cmd->cdb[0] == REQUEST_SENSE) {
1440                 rc = -EPIPE;
1441                 goto error;
1442         }
1443
1444         scmd = &sc->top_rqs_cmd;
1445         memset(scmd, 0, sizeof(struct ub_scsi_cmd));
1446         scmd->cdb[0] = REQUEST_SENSE;
1447         scmd->cdb[4] = UB_SENSE_SIZE;
1448         scmd->cdb_len = 6;
1449         scmd->dir = UB_DIR_READ;
1450         scmd->state = UB_CMDST_INIT;
1451         scmd->nsg = 1;
1452         sg = &scmd->sgv[0];
1453         sg_init_table(sg, UB_MAX_REQ_SG);
1454         sg_set_page(sg, virt_to_page(sc->top_sense), UB_SENSE_SIZE,
1455                         (unsigned long)sc->top_sense & (PAGE_SIZE-1));
1456         scmd->len = UB_SENSE_SIZE;
1457         scmd->lun = cmd->lun;
1458         scmd->done = ub_top_sense_done;
1459         scmd->back = cmd;
1460
1461         scmd->tag = sc->tagcnt++;
1462
1463         cmd->state = UB_CMDST_SENSE;
1464
1465         ub_cmdq_insert(sc, scmd);
1466         return;
1467
1468 error:
1469         ub_state_done(sc, cmd, rc);
1470 }
1471
1472 /*
1473  * A helper for the command's state machine:
1474  * Submit a stall clear.
1475  */
1476 static int ub_submit_clear_stall(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
1477     int stalled_pipe)
1478 {
1479         int endp;
1480         struct usb_ctrlrequest *cr;
1481         int rc;
1482
1483         endp = usb_pipeendpoint(stalled_pipe);
1484         if (usb_pipein (stalled_pipe))
1485                 endp |= USB_DIR_IN;
1486
1487         cr = &sc->work_cr;
1488         cr->bRequestType = USB_RECIP_ENDPOINT;
1489         cr->bRequest = USB_REQ_CLEAR_FEATURE;
1490         cr->wValue = cpu_to_le16(USB_ENDPOINT_HALT);
1491         cr->wIndex = cpu_to_le16(endp);
1492         cr->wLength = cpu_to_le16(0);
1493
1494         UB_INIT_COMPLETION(sc->work_done);
1495
1496         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->send_ctrl_pipe,
1497             (unsigned char*) cr, NULL, 0, ub_urb_complete, sc);
1498
1499         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
1500                 ub_complete(&sc->work_done);
1501                 return rc;
1502         }
1503
1504         sc->work_timer.expires = jiffies + UB_CTRL_TIMEOUT;
1505         add_timer(&sc->work_timer);
1506         return 0;
1507 }
1508
1509 /*
1510  */
1511 static void ub_top_sense_done(struct ub_dev *sc, struct ub_scsi_cmd *scmd)
1512 {
1513         unsigned char *sense = sc->top_sense;
1514         struct ub_scsi_cmd *cmd;
1515
1516         /*
1517          * Find the command which triggered the unit attention or a check,
1518          * save the sense into it, and advance its state machine.
1519          */
1520         if ((cmd = ub_cmdq_peek(sc)) == NULL) {
1521                 printk(KERN_WARNING "%s: sense done while idle\n", sc->name);
1522                 return;
1523         }
1524         if (cmd != scmd->back) {
1525                 printk(KERN_WARNING "%s: "
1526                     "sense done for wrong command 0x%x\n",
1527                     sc->name, cmd->tag);
1528                 return;
1529         }
1530         if (cmd->state != UB_CMDST_SENSE) {
1531                 printk(KERN_WARNING "%s: sense done with bad cmd state %d\n",
1532                     sc->name, cmd->state);
1533                 return;
1534         }
1535
1536         /*
1537          * Ignoring scmd->act_len, because the buffer was pre-zeroed.
1538          */
1539         cmd->key = sense[2] & 0x0F;
1540         cmd->asc = sense[12];
1541         cmd->ascq = sense[13];
1542
1543         ub_scsi_urb_compl(sc, cmd);
1544 }
1545
1546 /*
1547  * Reset management
1548  */
1549
1550 static void ub_reset_enter(struct ub_dev *sc, int try)
1551 {
1552
1553         if (sc->reset) {
1554                 /* This happens often on multi-LUN devices. */
1555                 return;
1556         }
1557         sc->reset = try + 1;
1558
1559 #if 0 /* Not needed because the disconnect waits for us. */
1560         unsigned long flags;
1561         spin_lock_irqsave(&ub_lock, flags);
1562         sc->openc++;
1563         spin_unlock_irqrestore(&ub_lock, flags);
1564 #endif
1565
1566 #if 0 /* We let them stop themselves. */
1567         struct ub_lun *lun;
1568         list_for_each_entry(lun, &sc->luns, link) {
1569                 blk_stop_queue(lun->disk->queue);
1570         }
1571 #endif
1572
1573         schedule_work(&sc->reset_work);
1574 }
1575
1576 static void ub_reset_task(struct work_struct *work)
1577 {
1578         struct ub_dev *sc = container_of(work, struct ub_dev, reset_work);
1579         unsigned long flags;
1580         struct ub_lun *lun;
1581         int rc;
1582
1583         if (!sc->reset) {
1584                 printk(KERN_WARNING "%s: Running reset unrequested\n",
1585                     sc->name);
1586                 return;
1587         }
1588
1589         if (atomic_read(&sc->poison)) {
1590                 ;
1591         } else if ((sc->reset & 1) == 0) {
1592                 ub_sync_reset(sc);
1593                 msleep(700);    /* usb-storage sleeps 6s (!) */
1594                 ub_probe_clear_stall(sc, sc->recv_bulk_pipe);
1595                 ub_probe_clear_stall(sc, sc->send_bulk_pipe);
1596         } else if (sc->dev->actconfig->desc.bNumInterfaces != 1) {
1597                 ;
1598         } else {
1599                 rc = usb_lock_device_for_reset(sc->dev, sc->intf);
1600                 if (rc < 0) {
1601                         printk(KERN_NOTICE
1602                             "%s: usb_lock_device_for_reset failed (%d)\n",
1603                             sc->name, rc);
1604                 } else {
1605                         rc = usb_reset_device(sc->dev);
1606                         if (rc < 0) {
1607                                 printk(KERN_NOTICE "%s: "
1608                                     "usb_lock_device_for_reset failed (%d)\n",
1609                                     sc->name, rc);
1610                         }
1611                         usb_unlock_device(sc->dev);
1612                 }
1613         }
1614
1615         /*
1616          * In theory, no commands can be running while reset is active,
1617          * so nobody can ask for another reset, and so we do not need any
1618          * queues of resets or anything. We do need a spinlock though,
1619          * to interact with block layer.
1620          */
1621         spin_lock_irqsave(sc->lock, flags);
1622         sc->reset = 0;
1623         tasklet_schedule(&sc->tasklet);
1624         list_for_each_entry(lun, &sc->luns, link) {
1625                 blk_start_queue(lun->disk->queue);
1626         }
1627         wake_up(&sc->reset_wait);
1628         spin_unlock_irqrestore(sc->lock, flags);
1629 }
1630
1631 /*
1632  * XXX Reset brackets are too much hassle to implement, so just stub them
1633  * in order to prevent forced unbinding (which deadlocks solid when our
1634  * ->disconnect method waits for the reset to complete and this kills keventd).
1635  *
1636  * XXX Tell Alan to move usb_unlock_device inside of usb_reset_device,
1637  * or else the post_reset is invoked, and restats I/O on a locked device.
1638  */
1639 static int ub_pre_reset(struct usb_interface *iface) {
1640         return 0;
1641 }
1642
1643 static int ub_post_reset(struct usb_interface *iface) {
1644         return 0;
1645 }
1646
1647 /*
1648  * This is called from a process context.
1649  */
1650 static void ub_revalidate(struct ub_dev *sc, struct ub_lun *lun)
1651 {
1652
1653         lun->readonly = 0;      /* XXX Query this from the device */
1654
1655         lun->capacity.nsec = 0;
1656         lun->capacity.bsize = 512;
1657         lun->capacity.bshift = 0;
1658
1659         if (ub_sync_tur(sc, lun) != 0)
1660                 return;                 /* Not ready */
1661         lun->changed = 0;
1662
1663         if (ub_sync_read_cap(sc, lun, &lun->capacity) != 0) {
1664                 /*
1665                  * The retry here means something is wrong, either with the
1666                  * device, with the transport, or with our code.
1667                  * We keep this because sd.c has retries for capacity.
1668                  */
1669                 if (ub_sync_read_cap(sc, lun, &lun->capacity) != 0) {
1670                         lun->capacity.nsec = 0;
1671                         lun->capacity.bsize = 512;
1672                         lun->capacity.bshift = 0;
1673                 }
1674         }
1675 }
1676
1677 /*
1678  * The open funcion.
1679  * This is mostly needed to keep refcounting, but also to support
1680  * media checks on removable media drives.
1681  */
1682 static int ub_bd_open(struct block_device *bdev, fmode_t mode)
1683 {
1684         struct ub_lun *lun = bdev->bd_disk->private_data;
1685         struct ub_dev *sc = lun->udev;
1686         unsigned long flags;
1687         int rc;
1688
1689         spin_lock_irqsave(&ub_lock, flags);
1690         if (atomic_read(&sc->poison)) {
1691                 spin_unlock_irqrestore(&ub_lock, flags);
1692                 return -ENXIO;
1693         }
1694         sc->openc++;
1695         spin_unlock_irqrestore(&ub_lock, flags);
1696
1697         if (lun->removable || lun->readonly)
1698                 check_disk_change(bdev);
1699
1700         /*
1701          * The sd.c considers ->media_present and ->changed not equivalent,
1702          * under some pretty murky conditions (a failure of READ CAPACITY).
1703          * We may need it one day.
1704          */
1705         if (lun->removable && lun->changed && !(mode & FMODE_NDELAY)) {
1706                 rc = -ENOMEDIUM;
1707                 goto err_open;
1708         }
1709
1710         if (lun->readonly && (mode & FMODE_WRITE)) {
1711                 rc = -EROFS;
1712                 goto err_open;
1713         }
1714
1715         return 0;
1716
1717 err_open:
1718         ub_put(sc);
1719         return rc;
1720 }
1721
1722 /*
1723  */
1724 static int ub_bd_release(struct gendisk *disk, fmode_t mode)
1725 {
1726         struct ub_lun *lun = disk->private_data;
1727         struct ub_dev *sc = lun->udev;
1728
1729         ub_put(sc);
1730         return 0;
1731 }
1732
1733 /*
1734  * The ioctl interface.
1735  */
1736 static int ub_bd_ioctl(struct block_device *bdev, fmode_t mode,
1737     unsigned int cmd, unsigned long arg)
1738 {
1739         struct gendisk *disk = bdev->bd_disk;
1740         void __user *usermem = (void __user *) arg;
1741
1742         return scsi_cmd_ioctl(disk->queue, disk, mode, cmd, usermem);
1743 }
1744
1745 /*
1746  * This is called by check_disk_change if we reported a media change.
1747  * The main onjective here is to discover the features of the media such as
1748  * the capacity, read-only status, etc. USB storage generally does not
1749  * need to be spun up, but if we needed it, this would be the place.
1750  *
1751  * This call can sleep.
1752  *
1753  * The return code is not used.
1754  */
1755 static int ub_bd_revalidate(struct gendisk *disk)
1756 {
1757         struct ub_lun *lun = disk->private_data;
1758
1759         ub_revalidate(lun->udev, lun);
1760
1761         /* XXX Support sector size switching like in sr.c */
1762         blk_queue_hardsect_size(disk->queue, lun->capacity.bsize);
1763         set_capacity(disk, lun->capacity.nsec);
1764         // set_disk_ro(sdkp->disk, lun->readonly);
1765
1766         return 0;
1767 }
1768
1769 /*
1770  * The check is called by the block layer to verify if the media
1771  * is still available. It is supposed to be harmless, lightweight and
1772  * non-intrusive in case the media was not changed.
1773  *
1774  * This call can sleep.
1775  *
1776  * The return code is bool!
1777  */
1778 static int ub_bd_media_changed(struct gendisk *disk)
1779 {
1780         struct ub_lun *lun = disk->private_data;
1781
1782         if (!lun->removable)
1783                 return 0;
1784
1785         /*
1786          * We clean checks always after every command, so this is not
1787          * as dangerous as it looks. If the TEST_UNIT_READY fails here,
1788          * the device is actually not ready with operator or software
1789          * intervention required. One dangerous item might be a drive which
1790          * spins itself down, and come the time to write dirty pages, this
1791          * will fail, then block layer discards the data. Since we never
1792          * spin drives up, such devices simply cannot be used with ub anyway.
1793          */
1794         if (ub_sync_tur(lun->udev, lun) != 0) {
1795                 lun->changed = 1;
1796                 return 1;
1797         }
1798
1799         return lun->changed;
1800 }
1801
1802 static struct block_device_operations ub_bd_fops = {
1803         .owner          = THIS_MODULE,
1804         .open           = ub_bd_open,
1805         .release        = ub_bd_release,
1806         .locked_ioctl   = ub_bd_ioctl,
1807         .media_changed  = ub_bd_media_changed,
1808         .revalidate_disk = ub_bd_revalidate,
1809 };
1810
1811 /*
1812  * Common ->done routine for commands executed synchronously.
1813  */
1814 static void ub_probe_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1815 {
1816         struct completion *cop = cmd->back;
1817         complete(cop);
1818 }
1819
1820 /*
1821  * Test if the device has a check condition on it, synchronously.
1822  */
1823 static int ub_sync_tur(struct ub_dev *sc, struct ub_lun *lun)
1824 {
1825         struct ub_scsi_cmd *cmd;
1826         enum { ALLOC_SIZE = sizeof(struct ub_scsi_cmd) };
1827         unsigned long flags;
1828         struct completion compl;
1829         int rc;
1830
1831         init_completion(&compl);
1832
1833         rc = -ENOMEM;
1834         if ((cmd = kzalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
1835                 goto err_alloc;
1836
1837         cmd->cdb[0] = TEST_UNIT_READY;
1838         cmd->cdb_len = 6;
1839         cmd->dir = UB_DIR_NONE;
1840         cmd->state = UB_CMDST_INIT;
1841         cmd->lun = lun;                 /* This may be NULL, but that's ok */
1842         cmd->done = ub_probe_done;
1843         cmd->back = &compl;
1844
1845         spin_lock_irqsave(sc->lock, flags);
1846         cmd->tag = sc->tagcnt++;
1847
1848         rc = ub_submit_scsi(sc, cmd);
1849         spin_unlock_irqrestore(sc->lock, flags);
1850
1851         if (rc != 0)
1852                 goto err_submit;
1853
1854         wait_for_completion(&compl);
1855
1856         rc = cmd->error;
1857
1858         if (rc == -EIO && cmd->key != 0)        /* Retries for benh's key */
1859                 rc = cmd->key;
1860
1861 err_submit:
1862         kfree(cmd);
1863 err_alloc:
1864         return rc;
1865 }
1866
1867 /*
1868  * Read the SCSI capacity synchronously (for probing).
1869  */
1870 static int ub_sync_read_cap(struct ub_dev *sc, struct ub_lun *lun,
1871     struct ub_capacity *ret)
1872 {
1873         struct ub_scsi_cmd *cmd;
1874         struct scatterlist *sg;
1875         char *p;
1876         enum { ALLOC_SIZE = sizeof(struct ub_scsi_cmd) + 8 };
1877         unsigned long flags;
1878         unsigned int bsize, shift;
1879         unsigned long nsec;
1880         struct completion compl;
1881         int rc;
1882
1883         init_completion(&compl);
1884
1885         rc = -ENOMEM;
1886         if ((cmd = kzalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
1887                 goto err_alloc;
1888         p = (char *)cmd + sizeof(struct ub_scsi_cmd);
1889
1890         cmd->cdb[0] = 0x25;
1891         cmd->cdb_len = 10;
1892         cmd->dir = UB_DIR_READ;
1893         cmd->state = UB_CMDST_INIT;
1894         cmd->nsg = 1;
1895         sg = &cmd->sgv[0];
1896         sg_init_table(sg, UB_MAX_REQ_SG);
1897         sg_set_page(sg, virt_to_page(p), 8, (unsigned long)p & (PAGE_SIZE-1));
1898         cmd->len = 8;
1899         cmd->lun = lun;
1900         cmd->done = ub_probe_done;
1901         cmd->back = &compl;
1902
1903         spin_lock_irqsave(sc->lock, flags);
1904         cmd->tag = sc->tagcnt++;
1905
1906         rc = ub_submit_scsi(sc, cmd);
1907         spin_unlock_irqrestore(sc->lock, flags);
1908
1909         if (rc != 0)
1910                 goto err_submit;
1911
1912         wait_for_completion(&compl);
1913
1914         if (cmd->error != 0) {
1915                 rc = -EIO;
1916                 goto err_read;
1917         }
1918         if (cmd->act_len != 8) {
1919                 rc = -EIO;
1920                 goto err_read;
1921         }
1922
1923         /* sd.c special-cases sector size of 0 to mean 512. Needed? Safe? */
1924         nsec = be32_to_cpu(*(__be32 *)p) + 1;
1925         bsize = be32_to_cpu(*(__be32 *)(p + 4));
1926         switch (bsize) {
1927         case 512:       shift = 0;      break;
1928         case 1024:      shift = 1;      break;
1929         case 2048:      shift = 2;      break;
1930         case 4096:      shift = 3;      break;
1931         default:
1932                 rc = -EDOM;
1933                 goto err_inv_bsize;
1934         }
1935
1936         ret->bsize = bsize;
1937         ret->bshift = shift;
1938         ret->nsec = nsec << shift;
1939         rc = 0;
1940
1941 err_inv_bsize:
1942 err_read:
1943 err_submit:
1944         kfree(cmd);
1945 err_alloc:
1946         return rc;
1947 }
1948
1949 /*
1950  */
1951 static void ub_probe_urb_complete(struct urb *urb)
1952 {
1953         struct completion *cop = urb->context;
1954         complete(cop);
1955 }
1956
1957 static void ub_probe_timeout(unsigned long arg)
1958 {
1959         struct completion *cop = (struct completion *) arg;
1960         complete(cop);
1961 }
1962
1963 /*
1964  * Reset with a Bulk reset.
1965  */
1966 static int ub_sync_reset(struct ub_dev *sc)
1967 {
1968         int ifnum = sc->intf->cur_altsetting->desc.bInterfaceNumber;
1969         struct usb_ctrlrequest *cr;
1970         struct completion compl;
1971         struct timer_list timer;
1972         int rc;
1973
1974         init_completion(&compl);
1975
1976         cr = &sc->work_cr;
1977         cr->bRequestType = USB_TYPE_CLASS | USB_RECIP_INTERFACE;
1978         cr->bRequest = US_BULK_RESET_REQUEST;
1979         cr->wValue = cpu_to_le16(0);
1980         cr->wIndex = cpu_to_le16(ifnum);
1981         cr->wLength = cpu_to_le16(0);
1982
1983         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->send_ctrl_pipe,
1984             (unsigned char*) cr, NULL, 0, ub_probe_urb_complete, &compl);
1985
1986         if ((rc = usb_submit_urb(&sc->work_urb, GFP_KERNEL)) != 0) {
1987                 printk(KERN_WARNING
1988                      "%s: Unable to submit a bulk reset (%d)\n", sc->name, rc);
1989                 return rc;
1990         }
1991
1992         init_timer(&timer);
1993         timer.function = ub_probe_timeout;
1994         timer.data = (unsigned long) &compl;
1995         timer.expires = jiffies + UB_CTRL_TIMEOUT;
1996         add_timer(&timer);
1997
1998         wait_for_completion(&compl);
1999
2000         del_timer_sync(&timer);
2001         usb_kill_urb(&sc->work_urb);
2002
2003         return sc->work_urb.status;
2004 }
2005
2006 /*
2007  * Get number of LUNs by the way of Bulk GetMaxLUN command.
2008  */
2009 static int ub_sync_getmaxlun(struct ub_dev *sc)
2010 {
2011         int ifnum = sc->intf->cur_altsetting->desc.bInterfaceNumber;
2012         unsigned char *p;
2013         enum { ALLOC_SIZE = 1 };
2014         struct usb_ctrlrequest *cr;
2015         struct completion compl;
2016         struct timer_list timer;
2017         int nluns;
2018         int rc;
2019
2020         init_completion(&compl);
2021
2022         rc = -ENOMEM;
2023         if ((p = kmalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
2024                 goto err_alloc;
2025         *p = 55;
2026
2027         cr = &sc->work_cr;
2028         cr->bRequestType = USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE;
2029         cr->bRequest = US_BULK_GET_MAX_LUN;
2030         cr->wValue = cpu_to_le16(0);
2031         cr->wIndex = cpu_to_le16(ifnum);
2032         cr->wLength = cpu_to_le16(1);
2033
2034         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->recv_ctrl_pipe,
2035             (unsigned char*) cr, p, 1, ub_probe_urb_complete, &compl);
2036
2037         if ((rc = usb_submit_urb(&sc->work_urb, GFP_KERNEL)) != 0)
2038                 goto err_submit;
2039
2040         init_timer(&timer);
2041         timer.function = ub_probe_timeout;
2042         timer.data = (unsigned long) &compl;
2043         timer.expires = jiffies + UB_CTRL_TIMEOUT;
2044         add_timer(&timer);
2045
2046         wait_for_completion(&compl);
2047
2048         del_timer_sync(&timer);
2049         usb_kill_urb(&sc->work_urb);
2050
2051         if ((rc = sc->work_urb.status) < 0)
2052                 goto err_io;
2053
2054         if (sc->work_urb.actual_length != 1) {
2055                 nluns = 0;
2056         } else {
2057                 if ((nluns = *p) == 55) {
2058                         nluns = 0;
2059                 } else {
2060                         /* GetMaxLUN returns the maximum LUN number */
2061                         nluns += 1;
2062                         if (nluns > UB_MAX_LUNS)
2063                                 nluns = UB_MAX_LUNS;
2064                 }
2065         }
2066
2067         kfree(p);
2068         return nluns;
2069
2070 err_io:
2071 err_submit:
2072         kfree(p);
2073 err_alloc:
2074         return rc;
2075 }
2076
2077 /*
2078  * Clear initial stalls.
2079  */
2080 static int ub_probe_clear_stall(struct ub_dev *sc, int stalled_pipe)
2081 {
2082         int endp;
2083         struct usb_ctrlrequest *cr;
2084         struct completion compl;
2085         struct timer_list timer;
2086         int rc;
2087
2088         init_completion(&compl);
2089
2090         endp = usb_pipeendpoint(stalled_pipe);
2091         if (usb_pipein (stalled_pipe))
2092                 endp |= USB_DIR_IN;
2093
2094         cr = &sc->work_cr;
2095         cr->bRequestType = USB_RECIP_ENDPOINT;
2096         cr->bRequest = USB_REQ_CLEAR_FEATURE;
2097         cr->wValue = cpu_to_le16(USB_ENDPOINT_HALT);
2098         cr->wIndex = cpu_to_le16(endp);
2099         cr->wLength = cpu_to_le16(0);
2100
2101         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->send_ctrl_pipe,
2102             (unsigned char*) cr, NULL, 0, ub_probe_urb_complete, &compl);
2103
2104         if ((rc = usb_submit_urb(&sc->work_urb, GFP_KERNEL)) != 0) {
2105                 printk(KERN_WARNING
2106                      "%s: Unable to submit a probe clear (%d)\n", sc->name, rc);
2107                 return rc;
2108         }
2109
2110         init_timer(&timer);
2111         timer.function = ub_probe_timeout;
2112         timer.data = (unsigned long) &compl;
2113         timer.expires = jiffies + UB_CTRL_TIMEOUT;
2114         add_timer(&timer);
2115
2116         wait_for_completion(&compl);
2117
2118         del_timer_sync(&timer);
2119         usb_kill_urb(&sc->work_urb);
2120
2121         usb_reset_endpoint(sc->dev, endp);
2122
2123         return 0;
2124 }
2125
2126 /*
2127  * Get the pipe settings.
2128  */
2129 static int ub_get_pipes(struct ub_dev *sc, struct usb_device *dev,
2130     struct usb_interface *intf)
2131 {
2132         struct usb_host_interface *altsetting = intf->cur_altsetting;
2133         struct usb_endpoint_descriptor *ep_in = NULL;
2134         struct usb_endpoint_descriptor *ep_out = NULL;
2135         struct usb_endpoint_descriptor *ep;
2136         int i;
2137
2138         /*
2139          * Find the endpoints we need.
2140          * We are expecting a minimum of 2 endpoints - in and out (bulk).
2141          * We will ignore any others.
2142          */
2143         for (i = 0; i < altsetting->desc.bNumEndpoints; i++) {
2144                 ep = &altsetting->endpoint[i].desc;
2145
2146                 /* Is it a BULK endpoint? */
2147                 if (usb_endpoint_xfer_bulk(ep)) {
2148                         /* BULK in or out? */
2149                         if (usb_endpoint_dir_in(ep)) {
2150                                 if (ep_in == NULL)
2151                                         ep_in = ep;
2152                         } else {
2153                                 if (ep_out == NULL)
2154                                         ep_out = ep;
2155                         }
2156                 }
2157         }
2158
2159         if (ep_in == NULL || ep_out == NULL) {
2160                 printk(KERN_NOTICE "%s: failed endpoint check\n", sc->name);
2161                 return -ENODEV;
2162         }
2163
2164         /* Calculate and store the pipe values */
2165         sc->send_ctrl_pipe = usb_sndctrlpipe(dev, 0);
2166         sc->recv_ctrl_pipe = usb_rcvctrlpipe(dev, 0);
2167         sc->send_bulk_pipe = usb_sndbulkpipe(dev,
2168                 usb_endpoint_num(ep_out));
2169         sc->recv_bulk_pipe = usb_rcvbulkpipe(dev,
2170                 usb_endpoint_num(ep_in));
2171
2172         return 0;
2173 }
2174
2175 /*
2176  * Probing is done in the process context, which allows us to cheat
2177  * and not to build a state machine for the discovery.
2178  */
2179 static int ub_probe(struct usb_interface *intf,
2180     const struct usb_device_id *dev_id)
2181 {
2182         struct ub_dev *sc;
2183         int nluns;
2184         int rc;
2185         int i;
2186
2187         if (usb_usual_check_type(dev_id, USB_US_TYPE_UB))
2188                 return -ENXIO;
2189
2190         rc = -ENOMEM;
2191         if ((sc = kzalloc(sizeof(struct ub_dev), GFP_KERNEL)) == NULL)
2192                 goto err_core;
2193         sc->lock = ub_next_lock();
2194         INIT_LIST_HEAD(&sc->luns);
2195         usb_init_urb(&sc->work_urb);
2196         tasklet_init(&sc->tasklet, ub_scsi_action, (unsigned long)sc);
2197         atomic_set(&sc->poison, 0);
2198         INIT_WORK(&sc->reset_work, ub_reset_task);
2199         init_waitqueue_head(&sc->reset_wait);
2200
2201         init_timer(&sc->work_timer);
2202         sc->work_timer.data = (unsigned long) sc;
2203         sc->work_timer.function = ub_urb_timeout;
2204
2205         ub_init_completion(&sc->work_done);
2206         sc->work_done.done = 1;         /* A little yuk, but oh well... */
2207
2208         sc->dev = interface_to_usbdev(intf);
2209         sc->intf = intf;
2210         // sc->ifnum = intf->cur_altsetting->desc.bInterfaceNumber;
2211         usb_set_intfdata(intf, sc);
2212         usb_get_dev(sc->dev);
2213         /*
2214          * Since we give the interface struct to the block level through
2215          * disk->driverfs_dev, we have to pin it. Otherwise, block_uevent
2216          * oopses on close after a disconnect (kernels 2.6.16 and up).
2217          */
2218         usb_get_intf(sc->intf);
2219
2220         snprintf(sc->name, 12, DRV_NAME "(%d.%d)",
2221             sc->dev->bus->busnum, sc->dev->devnum);
2222
2223         /* XXX Verify that we can handle the device (from descriptors) */
2224
2225         if (ub_get_pipes(sc, sc->dev, intf) != 0)
2226                 goto err_dev_desc;
2227
2228         /*
2229          * At this point, all USB initialization is done, do upper layer.
2230          * We really hate halfway initialized structures, so from the
2231          * invariants perspective, this ub_dev is fully constructed at
2232          * this point.
2233          */
2234
2235         /*
2236          * This is needed to clear toggles. It is a problem only if we do
2237          * `rmmod ub && modprobe ub` without disconnects, but we like that.
2238          */
2239 #if 0 /* iPod Mini fails if we do this (big white iPod works) */
2240         ub_probe_clear_stall(sc, sc->recv_bulk_pipe);
2241         ub_probe_clear_stall(sc, sc->send_bulk_pipe);
2242 #endif
2243
2244         /*
2245          * The way this is used by the startup code is a little specific.
2246          * A SCSI check causes a USB stall. Our common case code sees it
2247          * and clears the check, after which the device is ready for use.
2248          * But if a check was not present, any command other than
2249          * TEST_UNIT_READY ends with a lockup (including REQUEST_SENSE).
2250          *
2251          * If we neglect to clear the SCSI check, the first real command fails
2252          * (which is the capacity readout). We clear that and retry, but why
2253          * causing spurious retries for no reason.
2254          *
2255          * Revalidation may start with its own TEST_UNIT_READY, but that one
2256          * has to succeed, so we clear checks with an additional one here.
2257          * In any case it's not our business how revaliadation is implemented.
2258          */
2259         for (i = 0; i < 3; i++) {  /* Retries for the schwag key from KS'04 */
2260                 if ((rc = ub_sync_tur(sc, NULL)) <= 0) break;
2261                 if (rc != 0x6) break;
2262                 msleep(10);
2263         }
2264
2265         nluns = 1;
2266         for (i = 0; i < 3; i++) {
2267                 if ((rc = ub_sync_getmaxlun(sc)) < 0)
2268                         break;
2269                 if (rc != 0) {
2270                         nluns = rc;
2271                         break;
2272                 }
2273                 msleep(100);
2274         }
2275
2276         for (i = 0; i < nluns; i++) {
2277                 ub_probe_lun(sc, i);
2278         }
2279         return 0;
2280
2281 err_dev_desc:
2282         usb_set_intfdata(intf, NULL);
2283         usb_put_intf(sc->intf);
2284         usb_put_dev(sc->dev);
2285         kfree(sc);
2286 err_core:
2287         return rc;
2288 }
2289
2290 static int ub_probe_lun(struct ub_dev *sc, int lnum)
2291 {
2292         struct ub_lun *lun;
2293         struct request_queue *q;
2294         struct gendisk *disk;
2295         int rc;
2296
2297         rc = -ENOMEM;
2298         if ((lun = kzalloc(sizeof(struct ub_lun), GFP_KERNEL)) == NULL)
2299                 goto err_alloc;
2300         lun->num = lnum;
2301
2302         rc = -ENOSR;
2303         if ((lun->id = ub_id_get()) == -1)
2304                 goto err_id;
2305
2306         lun->udev = sc;
2307
2308         snprintf(lun->name, 16, DRV_NAME "%c(%d.%d.%d)",
2309             lun->id + 'a', sc->dev->bus->busnum, sc->dev->devnum, lun->num);
2310
2311         lun->removable = 1;             /* XXX Query this from the device */
2312         lun->changed = 1;               /* ub_revalidate clears only */
2313         ub_revalidate(sc, lun);
2314
2315         rc = -ENOMEM;
2316         if ((disk = alloc_disk(UB_PARTS_PER_LUN)) == NULL)
2317                 goto err_diskalloc;
2318
2319         sprintf(disk->disk_name, DRV_NAME "%c", lun->id + 'a');
2320         disk->major = UB_MAJOR;
2321         disk->first_minor = lun->id * UB_PARTS_PER_LUN;
2322         disk->fops = &ub_bd_fops;
2323         disk->private_data = lun;
2324         disk->driverfs_dev = &sc->intf->dev;
2325
2326         rc = -ENOMEM;
2327         if ((q = blk_init_queue(ub_request_fn, sc->lock)) == NULL)
2328                 goto err_blkqinit;
2329
2330         disk->queue = q;
2331
2332         blk_queue_bounce_limit(q, BLK_BOUNCE_HIGH);
2333         blk_queue_max_hw_segments(q, UB_MAX_REQ_SG);
2334         blk_queue_max_phys_segments(q, UB_MAX_REQ_SG);
2335         blk_queue_segment_boundary(q, 0xffffffff);      /* Dubious. */
2336         blk_queue_max_sectors(q, UB_MAX_SECTORS);
2337         blk_queue_hardsect_size(q, lun->capacity.bsize);
2338
2339         lun->disk = disk;
2340         q->queuedata = lun;
2341         list_add(&lun->link, &sc->luns);
2342
2343         set_capacity(disk, lun->capacity.nsec);
2344         if (lun->removable)
2345                 disk->flags |= GENHD_FL_REMOVABLE;
2346
2347         add_disk(disk);
2348
2349         return 0;
2350
2351 err_blkqinit:
2352         put_disk(disk);
2353 err_diskalloc:
2354         ub_id_put(lun->id);
2355 err_id:
2356         kfree(lun);
2357 err_alloc:
2358         return rc;
2359 }
2360
2361 static void ub_disconnect(struct usb_interface *intf)
2362 {
2363         struct ub_dev *sc = usb_get_intfdata(intf);
2364         struct ub_lun *lun;
2365         unsigned long flags;
2366
2367         /*
2368          * Prevent ub_bd_release from pulling the rug from under us.
2369          * XXX This is starting to look like a kref.
2370          * XXX Why not to take this ref at probe time?
2371          */
2372         spin_lock_irqsave(&ub_lock, flags);
2373         sc->openc++;
2374         spin_unlock_irqrestore(&ub_lock, flags);
2375
2376         /*
2377          * Fence stall clearings, operations triggered by unlinkings and so on.
2378          * We do not attempt to unlink any URBs, because we do not trust the
2379          * unlink paths in HC drivers. Also, we get -84 upon disconnect anyway.
2380          */
2381         atomic_set(&sc->poison, 1);
2382
2383         /*
2384          * Wait for reset to end, if any.
2385          */
2386         wait_event(sc->reset_wait, !sc->reset);
2387
2388         /*
2389          * Blow away queued commands.
2390          *
2391          * Actually, this never works, because before we get here
2392          * the HCD terminates outstanding URB(s). It causes our
2393          * SCSI command queue to advance, commands fail to submit,
2394          * and the whole queue drains. So, we just use this code to
2395          * print warnings.
2396          */
2397         spin_lock_irqsave(sc->lock, flags);
2398         {
2399                 struct ub_scsi_cmd *cmd;
2400                 int cnt = 0;
2401                 while ((cmd = ub_cmdq_peek(sc)) != NULL) {
2402                         cmd->error = -ENOTCONN;
2403                         cmd->state = UB_CMDST_DONE;
2404                         ub_cmdq_pop(sc);
2405                         (*cmd->done)(sc, cmd);
2406                         cnt++;
2407                 }
2408                 if (cnt != 0) {
2409                         printk(KERN_WARNING "%s: "
2410                             "%d was queued after shutdown\n", sc->name, cnt);
2411                 }
2412         }
2413         spin_unlock_irqrestore(sc->lock, flags);
2414
2415         /*
2416          * Unregister the upper layer.
2417          */
2418         list_for_each_entry(lun, &sc->luns, link) {
2419                 del_gendisk(lun->disk);
2420                 /*
2421                  * I wish I could do:
2422                  *    queue_flag_set(QUEUE_FLAG_DEAD, q);
2423                  * As it is, we rely on our internal poisoning and let
2424                  * the upper levels to spin furiously failing all the I/O.
2425                  */
2426         }
2427
2428         /*
2429          * Testing for -EINPROGRESS is always a bug, so we are bending
2430          * the rules a little.
2431          */
2432         spin_lock_irqsave(sc->lock, flags);
2433         if (sc->work_urb.status == -EINPROGRESS) {      /* janitors: ignore */
2434                 printk(KERN_WARNING "%s: "
2435                     "URB is active after disconnect\n", sc->name);
2436         }
2437         spin_unlock_irqrestore(sc->lock, flags);
2438
2439         /*
2440          * There is virtually no chance that other CPU runs a timeout so long
2441          * after ub_urb_complete should have called del_timer, but only if HCD
2442          * didn't forget to deliver a callback on unlink.
2443          */
2444         del_timer_sync(&sc->work_timer);
2445
2446         /*
2447          * At this point there must be no commands coming from anyone
2448          * and no URBs left in transit.
2449          */
2450
2451         ub_put(sc);
2452 }
2453
2454 static struct usb_driver ub_driver = {
2455         .name =         "ub",
2456         .probe =        ub_probe,
2457         .disconnect =   ub_disconnect,
2458         .id_table =     ub_usb_ids,
2459         .pre_reset =    ub_pre_reset,
2460         .post_reset =   ub_post_reset,
2461 };
2462
2463 static int __init ub_init(void)
2464 {
2465         int rc;
2466         int i;
2467
2468         for (i = 0; i < UB_QLOCK_NUM; i++)
2469                 spin_lock_init(&ub_qlockv[i]);
2470
2471         if ((rc = register_blkdev(UB_MAJOR, DRV_NAME)) != 0)
2472                 goto err_regblkdev;
2473
2474         if ((rc = usb_register(&ub_driver)) != 0)
2475                 goto err_register;
2476
2477         usb_usual_set_present(USB_US_TYPE_UB);
2478         return 0;
2479
2480 err_register:
2481         unregister_blkdev(UB_MAJOR, DRV_NAME);
2482 err_regblkdev:
2483         return rc;
2484 }
2485
2486 static void __exit ub_exit(void)
2487 {
2488         usb_deregister(&ub_driver);
2489
2490         unregister_blkdev(UB_MAJOR, DRV_NAME);
2491         usb_usual_clear_present(USB_US_TYPE_UB);
2492 }
2493
2494 module_init(ub_init);
2495 module_exit(ub_exit);
2496
2497 MODULE_LICENSE("GPL");