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