mtip32xx: make setting comp_time as common
[linux-2.6.git] / drivers / block / ub.c
1 /*
2  * The low performance USB storage driver (ub).
3  *
4  * Copyright (c) 1999, 2000 Matthew Dharm (mdharm-usb@one-eyed-alien.net)
5  * Copyright (C) 2004 Pete Zaitcev (zaitcev@yahoo.com)
6  *
7  * This work is a part of Linux kernel, is derived from it,
8  * and is not licensed separately. See file COPYING for details.
9  *
10  * TODO (sorted by decreasing priority)
11  *  -- Return sense now that rq allows it (we always auto-sense anyway).
12  *  -- set readonly flag for CDs, set removable flag for CF readers
13  *  -- do inquiry and verify we got a disk and not a tape (for LUN mismatch)
14  *  -- verify the 13 conditions and do bulk resets
15  *  -- highmem
16  *  -- move top_sense and work_bcs into separate allocations (if they survive)
17  *     for cache purists and esoteric architectures.
18  *  -- Allocate structure for LUN 0 before the first ub_sync_tur, avoid NULL. ?
19  *  -- prune comments, they are too volumnous
20  *  -- Resove XXX's
21  *  -- CLEAR, CLR2STS, CLRRS seem to be ripe for refactoring.
22  */
23 #include <linux/kernel.h>
24 #include <linux/module.h>
25 #include <linux/usb.h>
26 #include <linux/usb_usual.h>
27 #include <linux/blkdev.h>
28 #include <linux/timer.h>
29 #include <linux/scatterlist.h>
30 #include <linux/slab.h>
31 #include <linux/mutex.h>
32 #include <scsi/scsi.h>
33
34 #define DRV_NAME "ub"
35
36 #define UB_MAJOR 180
37
38 /*
39  * The command state machine is the key model for understanding of this driver.
40  *
41  * The general rule is that all transitions are done towards the bottom
42  * of the diagram, thus preventing any loops.
43  *
44  * An exception to that is how the STAT state is handled. A counter allows it
45  * to be re-entered along the path marked with [C].
46  *
47  *       +--------+
48  *       ! INIT   !
49  *       +--------+
50  *           !
51  *        ub_scsi_cmd_start fails ->--------------------------------------\
52  *           !                                                            !
53  *           V                                                            !
54  *       +--------+                                                       !
55  *       ! CMD    !                                                       !
56  *       +--------+                                                       !
57  *           !                                            +--------+      !
58  *         was -EPIPE -->-------------------------------->! CLEAR  !      !
59  *           !                                            +--------+      !
60  *           !                                                !           !
61  *         was error -->------------------------------------- ! --------->\
62  *           !                                                !           !
63  *  /--<-- cmd->dir == NONE ?                                 !           !
64  *  !        !                                                !           !
65  *  !        V                                                !           !
66  *  !    +--------+                                           !           !
67  *  !    ! DATA   !                                           !           !
68  *  !    +--------+                                           !           !
69  *  !        !                           +---------+          !           !
70  *  !      was -EPIPE -->--------------->! CLR2STS !          !           !
71  *  !        !                           +---------+          !           !
72  *  !        !                                !               !           !
73  *  !        !                              was error -->---- ! --------->\
74  *  !      was error -->--------------------- ! ------------- ! --------->\
75  *  !        !                                !               !           !
76  *  !        V                                !               !           !
77  *  \--->+--------+                           !               !           !
78  *       ! STAT   !<--------------------------/               !           !
79  *  /--->+--------+                                           !           !
80  *  !        !                                                !           !
81  * [C]     was -EPIPE -->-----------\                         !           !
82  *  !        !                      !                         !           !
83  *  +<---- len == 0                 !                         !           !
84  *  !        !                      !                         !           !
85  *  !      was error -->--------------------------------------!---------->\
86  *  !        !                      !                         !           !
87  *  +<---- bad CSW                  !                         !           !
88  *  +<---- bad tag                  !                         !           !
89  *  !        !                      V                         !           !
90  *  !        !                 +--------+                     !           !
91  *  !        !                 ! CLRRS  !                     !           !
92  *  !        !                 +--------+                     !           !
93  *  !        !                      !                         !           !
94  *  \------- ! --------------------[C]--------\               !           !
95  *           !                                !               !           !
96  *         cmd->error---\                +--------+           !           !
97  *           !          +--------------->! SENSE  !<----------/           !
98  *         STAT_FAIL----/                +--------+                       !
99  *           !                                !                           V
100  *           !                                V                      +--------+
101  *           \--------------------------------\--------------------->! DONE   !
102  *                                                                   +--------+
103  */
104
105 /*
106  * This many LUNs per USB device.
107  * Every one of them takes a host, see UB_MAX_HOSTS.
108  */
109 #define UB_MAX_LUNS   9
110
111 /*
112  */
113
114 #define UB_PARTS_PER_LUN      8
115
116 #define UB_MAX_CDB_SIZE      16         /* Corresponds to Bulk */
117
118 #define UB_SENSE_SIZE  18
119
120 /*
121  */
122
123 /* command block wrapper */
124 struct bulk_cb_wrap {
125         __le32  Signature;              /* contains 'USBC' */
126         u32     Tag;                    /* unique per command id */
127         __le32  DataTransferLength;     /* size of data */
128         u8      Flags;                  /* direction in bit 0 */
129         u8      Lun;                    /* LUN */
130         u8      Length;                 /* of of the CDB */
131         u8      CDB[UB_MAX_CDB_SIZE];   /* max command */
132 };
133
134 #define US_BULK_CB_WRAP_LEN     31
135 #define US_BULK_CB_SIGN         0x43425355      /*spells out USBC */
136 #define US_BULK_FLAG_IN         1
137 #define US_BULK_FLAG_OUT        0
138
139 /* command status wrapper */
140 struct bulk_cs_wrap {
141         __le32  Signature;              /* should = 'USBS' */
142         u32     Tag;                    /* same as original command */
143         __le32  Residue;                /* amount not transferred */
144         u8      Status;                 /* see below */
145 };
146
147 #define US_BULK_CS_WRAP_LEN     13
148 #define US_BULK_CS_SIGN         0x53425355      /* spells out 'USBS' */
149 #define US_BULK_STAT_OK         0
150 #define US_BULK_STAT_FAIL       1
151 #define US_BULK_STAT_PHASE      2
152
153 /* bulk-only class specific requests */
154 #define US_BULK_RESET_REQUEST   0xff
155 #define US_BULK_GET_MAX_LUN     0xfe
156
157 /*
158  */
159 struct ub_dev;
160
161 #define UB_MAX_REQ_SG   9       /* cdrecord requires 32KB and maybe a header */
162 #define UB_MAX_SECTORS 64
163
164 /*
165  * A second is more than enough for a 32K transfer (UB_MAX_SECTORS)
166  * even if a webcam hogs the bus, but some devices need time to spin up.
167  */
168 #define UB_URB_TIMEOUT  (HZ*2)
169 #define UB_DATA_TIMEOUT (HZ*5)  /* ZIP does spin-ups in the data phase */
170 #define UB_STAT_TIMEOUT (HZ*5)  /* Same spinups and eject for a dataless cmd. */
171 #define UB_CTRL_TIMEOUT (HZ/2)  /* 500ms ought to be enough to clear a stall */
172
173 /*
174  * An instance of a SCSI command in transit.
175  */
176 #define UB_DIR_NONE     0
177 #define UB_DIR_READ     1
178 #define UB_DIR_ILLEGAL2 2
179 #define UB_DIR_WRITE    3
180
181 #define UB_DIR_CHAR(c)  (((c)==UB_DIR_WRITE)? 'w': \
182                          (((c)==UB_DIR_READ)? 'r': 'n'))
183
184 enum ub_scsi_cmd_state {
185         UB_CMDST_INIT,                  /* Initial state */
186         UB_CMDST_CMD,                   /* Command submitted */
187         UB_CMDST_DATA,                  /* Data phase */
188         UB_CMDST_CLR2STS,               /* Clearing before requesting status */
189         UB_CMDST_STAT,                  /* Status phase */
190         UB_CMDST_CLEAR,                 /* Clearing a stall (halt, actually) */
191         UB_CMDST_CLRRS,                 /* Clearing before retrying status */
192         UB_CMDST_SENSE,                 /* Sending Request Sense */
193         UB_CMDST_DONE                   /* Final state */
194 };
195
196 struct ub_scsi_cmd {
197         unsigned char cdb[UB_MAX_CDB_SIZE];
198         unsigned char cdb_len;
199
200         unsigned char dir;              /* 0 - none, 1 - read, 3 - write. */
201         enum ub_scsi_cmd_state state;
202         unsigned int tag;
203         struct ub_scsi_cmd *next;
204
205         int error;                      /* Return code - valid upon done */
206         unsigned int act_len;           /* Return size */
207         unsigned char key, asc, ascq;   /* May be valid if error==-EIO */
208
209         int stat_count;                 /* Retries getting status. */
210         unsigned int timeo;             /* jiffies until rq->timeout changes */
211
212         unsigned int len;               /* Requested length */
213         unsigned int current_sg;
214         unsigned int nsg;               /* sgv[nsg] */
215         struct scatterlist sgv[UB_MAX_REQ_SG];
216
217         struct ub_lun *lun;
218         void (*done)(struct ub_dev *, struct ub_scsi_cmd *);
219         void *back;
220 };
221
222 struct ub_request {
223         struct request *rq;
224         unsigned int current_try;
225         unsigned int nsg;               /* sgv[nsg] */
226         struct scatterlist sgv[UB_MAX_REQ_SG];
227 };
228
229 /*
230  */
231 struct ub_capacity {
232         unsigned long nsec;             /* Linux size - 512 byte sectors */
233         unsigned int bsize;             /* Linux hardsect_size */
234         unsigned int bshift;            /* Shift between 512 and hard sects */
235 };
236
237 /*
238  * This is a direct take-off from linux/include/completion.h
239  * The difference is that I do not wait on this thing, just poll.
240  * When I want to wait (ub_probe), I just use the stock completion.
241  *
242  * Note that INIT_COMPLETION takes no lock. It is correct. But why
243  * in the bloody hell that thing takes struct instead of pointer to struct
244  * is quite beyond me. I just copied it from the stock completion.
245  */
246 struct ub_completion {
247         unsigned int done;
248         spinlock_t lock;
249 };
250
251 static DEFINE_MUTEX(ub_mutex);
252 static inline void ub_init_completion(struct ub_completion *x)
253 {
254         x->done = 0;
255         spin_lock_init(&x->lock);
256 }
257
258 #define UB_INIT_COMPLETION(x)   ((x).done = 0)
259
260 static void ub_complete(struct ub_completion *x)
261 {
262         unsigned long flags;
263
264         spin_lock_irqsave(&x->lock, flags);
265         x->done++;
266         spin_unlock_irqrestore(&x->lock, flags);
267 }
268
269 static int ub_is_completed(struct ub_completion *x)
270 {
271         unsigned long flags;
272         int ret;
273
274         spin_lock_irqsave(&x->lock, flags);
275         ret = x->done;
276         spin_unlock_irqrestore(&x->lock, flags);
277         return ret;
278 }
279
280 /*
281  */
282 struct ub_scsi_cmd_queue {
283         int qlen, qmax;
284         struct ub_scsi_cmd *head, *tail;
285 };
286
287 /*
288  * The block device instance (one per LUN).
289  */
290 struct ub_lun {
291         struct ub_dev *udev;
292         struct list_head link;
293         struct gendisk *disk;
294         int id;                         /* Host index */
295         int num;                        /* LUN number */
296         char name[16];
297
298         int changed;                    /* Media was changed */
299         int removable;
300         int readonly;
301
302         struct ub_request urq;
303
304         /* Use Ingo's mempool if or when we have more than one command. */
305         /*
306          * Currently we never need more than one command for the whole device.
307          * However, giving every LUN a command is a cheap and automatic way
308          * to enforce fairness between them.
309          */
310         int cmda[1];
311         struct ub_scsi_cmd cmdv[1];
312
313         struct ub_capacity capacity; 
314 };
315
316 /*
317  * The USB device instance.
318  */
319 struct ub_dev {
320         spinlock_t *lock;
321         atomic_t poison;                /* The USB device is disconnected */
322         int openc;                      /* protected by ub_lock! */
323                                         /* kref is too implicit for our taste */
324         int reset;                      /* Reset is running */
325         int bad_resid;
326         unsigned int tagcnt;
327         char name[12];
328         struct usb_device *dev;
329         struct usb_interface *intf;
330
331         struct list_head luns;
332
333         unsigned int send_bulk_pipe;    /* cached pipe values */
334         unsigned int recv_bulk_pipe;
335         unsigned int send_ctrl_pipe;
336         unsigned int recv_ctrl_pipe;
337
338         struct tasklet_struct tasklet;
339
340         struct ub_scsi_cmd_queue cmd_queue;
341         struct ub_scsi_cmd top_rqs_cmd; /* REQUEST SENSE */
342         unsigned char top_sense[UB_SENSE_SIZE];
343
344         struct ub_completion work_done;
345         struct urb work_urb;
346         struct timer_list work_timer;
347         int last_pipe;                  /* What might need clearing */
348         __le32 signature;               /* Learned signature */
349         struct bulk_cb_wrap work_bcb;
350         struct bulk_cs_wrap work_bcs;
351         struct usb_ctrlrequest work_cr;
352
353         struct work_struct reset_work;
354         wait_queue_head_t reset_wait;
355 };
356
357 /*
358  */
359 static void ub_cleanup(struct ub_dev *sc);
360 static int ub_request_fn_1(struct ub_lun *lun, struct request *rq);
361 static void ub_cmd_build_block(struct ub_dev *sc, struct ub_lun *lun,
362     struct ub_scsi_cmd *cmd, struct ub_request *urq);
363 static void ub_cmd_build_packet(struct ub_dev *sc, struct ub_lun *lun,
364     struct ub_scsi_cmd *cmd, struct ub_request *urq);
365 static void ub_rw_cmd_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
366 static void ub_end_rq(struct request *rq, unsigned int status);
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  usb_storage_usb_ids
397 #else
398
399 static const struct usb_device_id ub_usb_ids[] = {
400         { USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, USB_SC_SCSI, USB_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 = blk_peek_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                 blk_start_request(rq);
649                 ub_end_rq(rq, DID_NO_CONNECT << 16);
650                 return 0;
651         }
652
653         if (lun->changed && rq->cmd_type != REQ_TYPE_BLOCK_PC) {
654                 blk_start_request(rq);
655                 ub_end_rq(rq, SAM_STAT_CHECK_CONDITION);
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         blk_start_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
689         if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
690                 ub_cmd_build_packet(sc, lun, cmd, urq);
691         } else {
692                 ub_cmd_build_block(sc, lun, cmd, urq);
693         }
694         cmd->state = UB_CMDST_INIT;
695         cmd->lun = lun;
696         cmd->done = ub_rw_cmd_done;
697         cmd->back = urq;
698
699         cmd->tag = sc->tagcnt++;
700         if (ub_submit_scsi(sc, cmd) != 0)
701                 goto drop;
702
703         return 0;
704
705 drop:
706         ub_put_cmd(lun, cmd);
707         ub_end_rq(rq, DID_ERROR << 16);
708         return 0;
709 }
710
711 static void ub_cmd_build_block(struct ub_dev *sc, struct ub_lun *lun,
712     struct ub_scsi_cmd *cmd, struct ub_request *urq)
713 {
714         struct request *rq = urq->rq;
715         unsigned int block, nblks;
716
717         if (rq_data_dir(rq) == WRITE)
718                 cmd->dir = UB_DIR_WRITE;
719         else
720                 cmd->dir = UB_DIR_READ;
721
722         cmd->nsg = urq->nsg;
723         memcpy(cmd->sgv, urq->sgv, sizeof(struct scatterlist) * cmd->nsg);
724
725         /*
726          * build the command
727          *
728          * The call to blk_queue_logical_block_size() guarantees that request
729          * is aligned, but it is given in terms of 512 byte units, always.
730          */
731         block = blk_rq_pos(rq) >> lun->capacity.bshift;
732         nblks = blk_rq_sectors(rq) >> lun->capacity.bshift;
733
734         cmd->cdb[0] = (cmd->dir == UB_DIR_READ)? READ_10: WRITE_10;
735         /* 10-byte uses 4 bytes of LBA: 2147483648KB, 2097152MB, 2048GB */
736         cmd->cdb[2] = block >> 24;
737         cmd->cdb[3] = block >> 16;
738         cmd->cdb[4] = block >> 8;
739         cmd->cdb[5] = block;
740         cmd->cdb[7] = nblks >> 8;
741         cmd->cdb[8] = nblks;
742         cmd->cdb_len = 10;
743
744         cmd->len = blk_rq_bytes(rq);
745 }
746
747 static void ub_cmd_build_packet(struct ub_dev *sc, struct ub_lun *lun,
748     struct ub_scsi_cmd *cmd, struct ub_request *urq)
749 {
750         struct request *rq = urq->rq;
751
752         if (blk_rq_bytes(rq) == 0) {
753                 cmd->dir = UB_DIR_NONE;
754         } else {
755                 if (rq_data_dir(rq) == WRITE)
756                         cmd->dir = UB_DIR_WRITE;
757                 else
758                         cmd->dir = UB_DIR_READ;
759         }
760
761         cmd->nsg = urq->nsg;
762         memcpy(cmd->sgv, urq->sgv, sizeof(struct scatterlist) * cmd->nsg);
763
764         memcpy(&cmd->cdb, rq->cmd, rq->cmd_len);
765         cmd->cdb_len = rq->cmd_len;
766
767         cmd->len = blk_rq_bytes(rq);
768
769         /*
770          * To reapply this to every URB is not as incorrect as it looks.
771          * In return, we avoid any complicated tracking calculations.
772          */
773         cmd->timeo = rq->timeout;
774 }
775
776 static void ub_rw_cmd_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
777 {
778         struct ub_lun *lun = cmd->lun;
779         struct ub_request *urq = cmd->back;
780         struct request *rq;
781         unsigned int scsi_status;
782
783         rq = urq->rq;
784
785         if (cmd->error == 0) {
786                 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
787                         if (cmd->act_len >= rq->resid_len)
788                                 rq->resid_len = 0;
789                         else
790                                 rq->resid_len -= cmd->act_len;
791                         scsi_status = 0;
792                 } else {
793                         if (cmd->act_len != cmd->len) {
794                                 scsi_status = SAM_STAT_CHECK_CONDITION;
795                         } else {
796                                 scsi_status = 0;
797                         }
798                 }
799         } else {
800                 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
801                         /* UB_SENSE_SIZE is smaller than SCSI_SENSE_BUFFERSIZE */
802                         memcpy(rq->sense, sc->top_sense, UB_SENSE_SIZE);
803                         rq->sense_len = UB_SENSE_SIZE;
804                         if (sc->top_sense[0] != 0)
805                                 scsi_status = SAM_STAT_CHECK_CONDITION;
806                         else
807                                 scsi_status = DID_ERROR << 16;
808                 } else {
809                         if (cmd->error == -EIO &&
810                             (cmd->key == 0 ||
811                              cmd->key == MEDIUM_ERROR ||
812                              cmd->key == UNIT_ATTENTION)) {
813                                 if (ub_rw_cmd_retry(sc, lun, urq, cmd) == 0)
814                                         return;
815                         }
816                         scsi_status = SAM_STAT_CHECK_CONDITION;
817                 }
818         }
819
820         urq->rq = NULL;
821
822         ub_put_cmd(lun, cmd);
823         ub_end_rq(rq, scsi_status);
824         blk_start_queue(lun->disk->queue);
825 }
826
827 static void ub_end_rq(struct request *rq, unsigned int scsi_status)
828 {
829         int error;
830
831         if (scsi_status == 0) {
832                 error = 0;
833         } else {
834                 error = -EIO;
835                 rq->errors = scsi_status;
836         }
837         __blk_end_request_all(rq, error);
838 }
839
840 static int ub_rw_cmd_retry(struct ub_dev *sc, struct ub_lun *lun,
841     struct ub_request *urq, struct ub_scsi_cmd *cmd)
842 {
843
844         if (atomic_read(&sc->poison))
845                 return -ENXIO;
846
847         ub_reset_enter(sc, urq->current_try);
848
849         if (urq->current_try >= 3)
850                 return -EIO;
851         urq->current_try++;
852
853         /* Remove this if anyone complains of flooding. */
854         printk(KERN_DEBUG "%s: dir %c len/act %d/%d "
855             "[sense %x %02x %02x] retry %d\n",
856             sc->name, UB_DIR_CHAR(cmd->dir), cmd->len, cmd->act_len,
857             cmd->key, cmd->asc, cmd->ascq, urq->current_try);
858
859         memset(cmd, 0, sizeof(struct ub_scsi_cmd));
860         ub_cmd_build_block(sc, lun, cmd, urq);
861
862         cmd->state = UB_CMDST_INIT;
863         cmd->lun = lun;
864         cmd->done = ub_rw_cmd_done;
865         cmd->back = urq;
866
867         cmd->tag = sc->tagcnt++;
868
869 #if 0 /* Wasteful */
870         return ub_submit_scsi(sc, cmd);
871 #else
872         ub_cmdq_add(sc, cmd);
873         return 0;
874 #endif
875 }
876
877 /*
878  * Submit a regular SCSI operation (not an auto-sense).
879  *
880  * The Iron Law of Good Submit Routine is:
881  * Zero return - callback is done, Nonzero return - callback is not done.
882  * No exceptions.
883  *
884  * Host is assumed locked.
885  */
886 static int ub_submit_scsi(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
887 {
888
889         if (cmd->state != UB_CMDST_INIT ||
890             (cmd->dir != UB_DIR_NONE && cmd->len == 0)) {
891                 return -EINVAL;
892         }
893
894         ub_cmdq_add(sc, cmd);
895         /*
896          * We can call ub_scsi_dispatch(sc) right away here, but it's a little
897          * safer to jump to a tasklet, in case upper layers do something silly.
898          */
899         tasklet_schedule(&sc->tasklet);
900         return 0;
901 }
902
903 /*
904  * Submit the first URB for the queued command.
905  * This function does not deal with queueing in any way.
906  */
907 static int ub_scsi_cmd_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
908 {
909         struct bulk_cb_wrap *bcb;
910         int rc;
911
912         bcb = &sc->work_bcb;
913
914         /*
915          * ``If the allocation length is eighteen or greater, and a device
916          * server returns less than eithteen bytes of data, the application
917          * client should assume that the bytes not transferred would have been
918          * zeroes had the device server returned those bytes.''
919          *
920          * We zero sense for all commands so that when a packet request
921          * fails it does not return a stale sense.
922          */
923         memset(&sc->top_sense, 0, UB_SENSE_SIZE);
924
925         /* set up the command wrapper */
926         bcb->Signature = cpu_to_le32(US_BULK_CB_SIGN);
927         bcb->Tag = cmd->tag;            /* Endianness is not important */
928         bcb->DataTransferLength = cpu_to_le32(cmd->len);
929         bcb->Flags = (cmd->dir == UB_DIR_READ) ? 0x80 : 0;
930         bcb->Lun = (cmd->lun != NULL) ? cmd->lun->num : 0;
931         bcb->Length = cmd->cdb_len;
932
933         /* copy the command payload */
934         memcpy(bcb->CDB, cmd->cdb, UB_MAX_CDB_SIZE);
935
936         UB_INIT_COMPLETION(sc->work_done);
937
938         sc->last_pipe = sc->send_bulk_pipe;
939         usb_fill_bulk_urb(&sc->work_urb, sc->dev, sc->send_bulk_pipe,
940             bcb, US_BULK_CB_WRAP_LEN, ub_urb_complete, sc);
941
942         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
943                 /* XXX Clear stalls */
944                 ub_complete(&sc->work_done);
945                 return rc;
946         }
947
948         sc->work_timer.expires = jiffies + UB_URB_TIMEOUT;
949         add_timer(&sc->work_timer);
950
951         cmd->state = UB_CMDST_CMD;
952         return 0;
953 }
954
955 /*
956  * Timeout handler.
957  */
958 static void ub_urb_timeout(unsigned long arg)
959 {
960         struct ub_dev *sc = (struct ub_dev *) arg;
961         unsigned long flags;
962
963         spin_lock_irqsave(sc->lock, flags);
964         if (!ub_is_completed(&sc->work_done))
965                 usb_unlink_urb(&sc->work_urb);
966         spin_unlock_irqrestore(sc->lock, flags);
967 }
968
969 /*
970  * Completion routine for the work URB.
971  *
972  * This can be called directly from usb_submit_urb (while we have
973  * the sc->lock taken) and from an interrupt (while we do NOT have
974  * the sc->lock taken). Therefore, bounce this off to a tasklet.
975  */
976 static void ub_urb_complete(struct urb *urb)
977 {
978         struct ub_dev *sc = urb->context;
979
980         ub_complete(&sc->work_done);
981         tasklet_schedule(&sc->tasklet);
982 }
983
984 static void ub_scsi_action(unsigned long _dev)
985 {
986         struct ub_dev *sc = (struct ub_dev *) _dev;
987         unsigned long flags;
988
989         spin_lock_irqsave(sc->lock, flags);
990         ub_scsi_dispatch(sc);
991         spin_unlock_irqrestore(sc->lock, flags);
992 }
993
994 static void ub_scsi_dispatch(struct ub_dev *sc)
995 {
996         struct ub_scsi_cmd *cmd;
997         int rc;
998
999         while (!sc->reset && (cmd = ub_cmdq_peek(sc)) != NULL) {
1000                 if (cmd->state == UB_CMDST_DONE) {
1001                         ub_cmdq_pop(sc);
1002                         (*cmd->done)(sc, cmd);
1003                 } else if (cmd->state == UB_CMDST_INIT) {
1004                         if ((rc = ub_scsi_cmd_start(sc, cmd)) == 0)
1005                                 break;
1006                         cmd->error = rc;
1007                         cmd->state = UB_CMDST_DONE;
1008                 } else {
1009                         if (!ub_is_completed(&sc->work_done))
1010                                 break;
1011                         del_timer(&sc->work_timer);
1012                         ub_scsi_urb_compl(sc, cmd);
1013                 }
1014         }
1015 }
1016
1017 static void ub_scsi_urb_compl(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1018 {
1019         struct urb *urb = &sc->work_urb;
1020         struct bulk_cs_wrap *bcs;
1021         int endp;
1022         int len;
1023         int rc;
1024
1025         if (atomic_read(&sc->poison)) {
1026                 ub_state_done(sc, cmd, -ENODEV);
1027                 return;
1028         }
1029
1030         endp = usb_pipeendpoint(sc->last_pipe);
1031         if (usb_pipein(sc->last_pipe))
1032                 endp |= USB_DIR_IN;
1033
1034         if (cmd->state == UB_CMDST_CLEAR) {
1035                 if (urb->status == -EPIPE) {
1036                         /*
1037                          * STALL while clearning STALL.
1038                          * The control pipe clears itself - nothing to do.
1039                          */
1040                         printk(KERN_NOTICE "%s: stall on control pipe\n",
1041                             sc->name);
1042                         goto Bad_End;
1043                 }
1044
1045                 /*
1046                  * We ignore the result for the halt clear.
1047                  */
1048
1049                 usb_reset_endpoint(sc->dev, endp);
1050
1051                 ub_state_sense(sc, cmd);
1052
1053         } else if (cmd->state == UB_CMDST_CLR2STS) {
1054                 if (urb->status == -EPIPE) {
1055                         printk(KERN_NOTICE "%s: stall on control pipe\n",
1056                             sc->name);
1057                         goto Bad_End;
1058                 }
1059
1060                 /*
1061                  * We ignore the result for the halt clear.
1062                  */
1063
1064                 usb_reset_endpoint(sc->dev, endp);
1065
1066                 ub_state_stat(sc, cmd);
1067
1068         } else if (cmd->state == UB_CMDST_CLRRS) {
1069                 if (urb->status == -EPIPE) {
1070                         printk(KERN_NOTICE "%s: stall on control pipe\n",
1071                             sc->name);
1072                         goto Bad_End;
1073                 }
1074
1075                 /*
1076                  * We ignore the result for the halt clear.
1077                  */
1078
1079                 usb_reset_endpoint(sc->dev, endp);
1080
1081                 ub_state_stat_counted(sc, cmd);
1082
1083         } else if (cmd->state == UB_CMDST_CMD) {
1084                 switch (urb->status) {
1085                 case 0:
1086                         break;
1087                 case -EOVERFLOW:
1088                         goto Bad_End;
1089                 case -EPIPE:
1090                         rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
1091                         if (rc != 0) {
1092                                 printk(KERN_NOTICE "%s: "
1093                                     "unable to submit clear (%d)\n",
1094                                     sc->name, rc);
1095                                 /*
1096                                  * This is typically ENOMEM or some other such shit.
1097                                  * Retrying is pointless. Just do Bad End on it...
1098                                  */
1099                                 ub_state_done(sc, cmd, rc);
1100                                 return;
1101                         }
1102                         cmd->state = UB_CMDST_CLEAR;
1103                         return;
1104                 case -ESHUTDOWN:        /* unplug */
1105                 case -EILSEQ:           /* unplug timeout on uhci */
1106                         ub_state_done(sc, cmd, -ENODEV);
1107                         return;
1108                 default:
1109                         goto Bad_End;
1110                 }
1111                 if (urb->actual_length != US_BULK_CB_WRAP_LEN) {
1112                         goto Bad_End;
1113                 }
1114
1115                 if (cmd->dir == UB_DIR_NONE || cmd->nsg < 1) {
1116                         ub_state_stat(sc, cmd);
1117                         return;
1118                 }
1119
1120                 // udelay(125);         // usb-storage has this
1121                 ub_data_start(sc, cmd);
1122
1123         } else if (cmd->state == UB_CMDST_DATA) {
1124                 if (urb->status == -EPIPE) {
1125                         rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
1126                         if (rc != 0) {
1127                                 printk(KERN_NOTICE "%s: "
1128                                     "unable to submit clear (%d)\n",
1129                                     sc->name, rc);
1130                                 ub_state_done(sc, cmd, rc);
1131                                 return;
1132                         }
1133                         cmd->state = UB_CMDST_CLR2STS;
1134                         return;
1135                 }
1136                 if (urb->status == -EOVERFLOW) {
1137                         /*
1138                          * A babble? Failure, but we must transfer CSW now.
1139                          */
1140                         cmd->error = -EOVERFLOW;        /* A cheap trick... */
1141                         ub_state_stat(sc, cmd);
1142                         return;
1143                 }
1144
1145                 if (cmd->dir == UB_DIR_WRITE) {
1146                         /*
1147                          * Do not continue writes in case of a failure.
1148                          * Doing so would cause sectors to be mixed up,
1149                          * which is worse than sectors lost.
1150                          *
1151                          * We must try to read the CSW, or many devices
1152                          * get confused.
1153                          */
1154                         len = urb->actual_length;
1155                         if (urb->status != 0 ||
1156                             len != cmd->sgv[cmd->current_sg].length) {
1157                                 cmd->act_len += len;
1158
1159                                 cmd->error = -EIO;
1160                                 ub_state_stat(sc, cmd);
1161                                 return;
1162                         }
1163
1164                 } else {
1165                         /*
1166                          * If an error occurs on read, we record it, and
1167                          * continue to fetch data in order to avoid bubble.
1168                          *
1169                          * As a small shortcut, we stop if we detect that
1170                          * a CSW mixed into data.
1171                          */
1172                         if (urb->status != 0)
1173                                 cmd->error = -EIO;
1174
1175                         len = urb->actual_length;
1176                         if (urb->status != 0 ||
1177                             len != cmd->sgv[cmd->current_sg].length) {
1178                                 if ((len & 0x1FF) == US_BULK_CS_WRAP_LEN)
1179                                         goto Bad_End;
1180                         }
1181                 }
1182
1183                 cmd->act_len += urb->actual_length;
1184
1185                 if (++cmd->current_sg < cmd->nsg) {
1186                         ub_data_start(sc, cmd);
1187                         return;
1188                 }
1189                 ub_state_stat(sc, cmd);
1190
1191         } else if (cmd->state == UB_CMDST_STAT) {
1192                 if (urb->status == -EPIPE) {
1193                         rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
1194                         if (rc != 0) {
1195                                 printk(KERN_NOTICE "%s: "
1196                                     "unable to submit clear (%d)\n",
1197                                     sc->name, rc);
1198                                 ub_state_done(sc, cmd, rc);
1199                                 return;
1200                         }
1201
1202                         /*
1203                          * Having a stall when getting CSW is an error, so
1204                          * make sure uppper levels are not oblivious to it.
1205                          */
1206                         cmd->error = -EIO;              /* A cheap trick... */
1207
1208                         cmd->state = UB_CMDST_CLRRS;
1209                         return;
1210                 }
1211
1212                 /* Catch everything, including -EOVERFLOW and other nasties. */
1213                 if (urb->status != 0)
1214                         goto Bad_End;
1215
1216                 if (urb->actual_length == 0) {
1217                         ub_state_stat_counted(sc, cmd);
1218                         return;
1219                 }
1220
1221                 /*
1222                  * Check the returned Bulk protocol status.
1223                  * The status block has to be validated first.
1224                  */
1225
1226                 bcs = &sc->work_bcs;
1227
1228                 if (sc->signature == cpu_to_le32(0)) {
1229                         /*
1230                          * This is the first reply, so do not perform the check.
1231                          * Instead, remember the signature the device uses
1232                          * for future checks. But do not allow a nul.
1233                          */
1234                         sc->signature = bcs->Signature;
1235                         if (sc->signature == cpu_to_le32(0)) {
1236                                 ub_state_stat_counted(sc, cmd);
1237                                 return;
1238                         }
1239                 } else {
1240                         if (bcs->Signature != sc->signature) {
1241                                 ub_state_stat_counted(sc, cmd);
1242                                 return;
1243                         }
1244                 }
1245
1246                 if (bcs->Tag != cmd->tag) {
1247                         /*
1248                          * This usually happens when we disagree with the
1249                          * device's microcode about something. For instance,
1250                          * a few of them throw this after timeouts. They buffer
1251                          * commands and reply at commands we timed out before.
1252                          * Without flushing these replies we loop forever.
1253                          */
1254                         ub_state_stat_counted(sc, cmd);
1255                         return;
1256                 }
1257
1258                 if (!sc->bad_resid) {
1259                         len = le32_to_cpu(bcs->Residue);
1260                         if (len != cmd->len - cmd->act_len) {
1261                                 /*
1262                                  * Only start ignoring if this cmd ended well.
1263                                  */
1264                                 if (cmd->len == cmd->act_len) {
1265                                         printk(KERN_NOTICE "%s: "
1266                                             "bad residual %d of %d, ignoring\n",
1267                                             sc->name, len, cmd->len);
1268                                         sc->bad_resid = 1;
1269                                 }
1270                         }
1271                 }
1272
1273                 switch (bcs->Status) {
1274                 case US_BULK_STAT_OK:
1275                         break;
1276                 case US_BULK_STAT_FAIL:
1277                         ub_state_sense(sc, cmd);
1278                         return;
1279                 case US_BULK_STAT_PHASE:
1280                         goto Bad_End;
1281                 default:
1282                         printk(KERN_INFO "%s: unknown CSW status 0x%x\n",
1283                             sc->name, bcs->Status);
1284                         ub_state_done(sc, cmd, -EINVAL);
1285                         return;
1286                 }
1287
1288                 /* Not zeroing error to preserve a babble indicator */
1289                 if (cmd->error != 0) {
1290                         ub_state_sense(sc, cmd);
1291                         return;
1292                 }
1293                 cmd->state = UB_CMDST_DONE;
1294                 ub_cmdq_pop(sc);
1295                 (*cmd->done)(sc, cmd);
1296
1297         } else if (cmd->state == UB_CMDST_SENSE) {
1298                 ub_state_done(sc, cmd, -EIO);
1299
1300         } else {
1301                 printk(KERN_WARNING "%s: wrong command state %d\n",
1302                     sc->name, cmd->state);
1303                 ub_state_done(sc, cmd, -EINVAL);
1304                 return;
1305         }
1306         return;
1307
1308 Bad_End: /* Little Excel is dead */
1309         ub_state_done(sc, cmd, -EIO);
1310 }
1311
1312 /*
1313  * Factorization helper for the command state machine:
1314  * Initiate a data segment transfer.
1315  */
1316 static void ub_data_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1317 {
1318         struct scatterlist *sg = &cmd->sgv[cmd->current_sg];
1319         int pipe;
1320         int rc;
1321
1322         UB_INIT_COMPLETION(sc->work_done);
1323
1324         if (cmd->dir == UB_DIR_READ)
1325                 pipe = sc->recv_bulk_pipe;
1326         else
1327                 pipe = sc->send_bulk_pipe;
1328         sc->last_pipe = pipe;
1329         usb_fill_bulk_urb(&sc->work_urb, sc->dev, pipe, sg_virt(sg),
1330             sg->length, ub_urb_complete, sc);
1331
1332         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
1333                 /* XXX Clear stalls */
1334                 ub_complete(&sc->work_done);
1335                 ub_state_done(sc, cmd, rc);
1336                 return;
1337         }
1338
1339         if (cmd->timeo)
1340                 sc->work_timer.expires = jiffies + cmd->timeo;
1341         else
1342                 sc->work_timer.expires = jiffies + UB_DATA_TIMEOUT;
1343         add_timer(&sc->work_timer);
1344
1345         cmd->state = UB_CMDST_DATA;
1346 }
1347
1348 /*
1349  * Factorization helper for the command state machine:
1350  * Finish the command.
1351  */
1352 static void ub_state_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd, int rc)
1353 {
1354
1355         cmd->error = rc;
1356         cmd->state = UB_CMDST_DONE;
1357         ub_cmdq_pop(sc);
1358         (*cmd->done)(sc, cmd);
1359 }
1360
1361 /*
1362  * Factorization helper for the command state machine:
1363  * Submit a CSW read.
1364  */
1365 static int __ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1366 {
1367         int rc;
1368
1369         UB_INIT_COMPLETION(sc->work_done);
1370
1371         sc->last_pipe = sc->recv_bulk_pipe;
1372         usb_fill_bulk_urb(&sc->work_urb, sc->dev, sc->recv_bulk_pipe,
1373             &sc->work_bcs, US_BULK_CS_WRAP_LEN, ub_urb_complete, sc);
1374
1375         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
1376                 /* XXX Clear stalls */
1377                 ub_complete(&sc->work_done);
1378                 ub_state_done(sc, cmd, rc);
1379                 return -1;
1380         }
1381
1382         if (cmd->timeo)
1383                 sc->work_timer.expires = jiffies + cmd->timeo;
1384         else
1385                 sc->work_timer.expires = jiffies + UB_STAT_TIMEOUT;
1386         add_timer(&sc->work_timer);
1387         return 0;
1388 }
1389
1390 /*
1391  * Factorization helper for the command state machine:
1392  * Submit a CSW read and go to STAT state.
1393  */
1394 static void ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1395 {
1396
1397         if (__ub_state_stat(sc, cmd) != 0)
1398                 return;
1399
1400         cmd->stat_count = 0;
1401         cmd->state = UB_CMDST_STAT;
1402 }
1403
1404 /*
1405  * Factorization helper for the command state machine:
1406  * Submit a CSW read and go to STAT state with counter (along [C] path).
1407  */
1408 static void ub_state_stat_counted(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1409 {
1410
1411         if (++cmd->stat_count >= 4) {
1412                 ub_state_sense(sc, cmd);
1413                 return;
1414         }
1415
1416         if (__ub_state_stat(sc, cmd) != 0)
1417                 return;
1418
1419         cmd->state = UB_CMDST_STAT;
1420 }
1421
1422 /*
1423  * Factorization helper for the command state machine:
1424  * Submit a REQUEST SENSE and go to SENSE state.
1425  */
1426 static void ub_state_sense(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1427 {
1428         struct ub_scsi_cmd *scmd;
1429         struct scatterlist *sg;
1430         int rc;
1431
1432         if (cmd->cdb[0] == REQUEST_SENSE) {
1433                 rc = -EPIPE;
1434                 goto error;
1435         }
1436
1437         scmd = &sc->top_rqs_cmd;
1438         memset(scmd, 0, sizeof(struct ub_scsi_cmd));
1439         scmd->cdb[0] = REQUEST_SENSE;
1440         scmd->cdb[4] = UB_SENSE_SIZE;
1441         scmd->cdb_len = 6;
1442         scmd->dir = UB_DIR_READ;
1443         scmd->state = UB_CMDST_INIT;
1444         scmd->nsg = 1;
1445         sg = &scmd->sgv[0];
1446         sg_init_table(sg, UB_MAX_REQ_SG);
1447         sg_set_page(sg, virt_to_page(sc->top_sense), UB_SENSE_SIZE,
1448                         (unsigned long)sc->top_sense & (PAGE_SIZE-1));
1449         scmd->len = UB_SENSE_SIZE;
1450         scmd->lun = cmd->lun;
1451         scmd->done = ub_top_sense_done;
1452         scmd->back = cmd;
1453
1454         scmd->tag = sc->tagcnt++;
1455
1456         cmd->state = UB_CMDST_SENSE;
1457
1458         ub_cmdq_insert(sc, scmd);
1459         return;
1460
1461 error:
1462         ub_state_done(sc, cmd, rc);
1463 }
1464
1465 /*
1466  * A helper for the command's state machine:
1467  * Submit a stall clear.
1468  */
1469 static int ub_submit_clear_stall(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
1470     int stalled_pipe)
1471 {
1472         int endp;
1473         struct usb_ctrlrequest *cr;
1474         int rc;
1475
1476         endp = usb_pipeendpoint(stalled_pipe);
1477         if (usb_pipein (stalled_pipe))
1478                 endp |= USB_DIR_IN;
1479
1480         cr = &sc->work_cr;
1481         cr->bRequestType = USB_RECIP_ENDPOINT;
1482         cr->bRequest = USB_REQ_CLEAR_FEATURE;
1483         cr->wValue = cpu_to_le16(USB_ENDPOINT_HALT);
1484         cr->wIndex = cpu_to_le16(endp);
1485         cr->wLength = cpu_to_le16(0);
1486
1487         UB_INIT_COMPLETION(sc->work_done);
1488
1489         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->send_ctrl_pipe,
1490             (unsigned char*) cr, NULL, 0, ub_urb_complete, sc);
1491
1492         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
1493                 ub_complete(&sc->work_done);
1494                 return rc;
1495         }
1496
1497         sc->work_timer.expires = jiffies + UB_CTRL_TIMEOUT;
1498         add_timer(&sc->work_timer);
1499         return 0;
1500 }
1501
1502 /*
1503  */
1504 static void ub_top_sense_done(struct ub_dev *sc, struct ub_scsi_cmd *scmd)
1505 {
1506         unsigned char *sense = sc->top_sense;
1507         struct ub_scsi_cmd *cmd;
1508
1509         /*
1510          * Find the command which triggered the unit attention or a check,
1511          * save the sense into it, and advance its state machine.
1512          */
1513         if ((cmd = ub_cmdq_peek(sc)) == NULL) {
1514                 printk(KERN_WARNING "%s: sense done while idle\n", sc->name);
1515                 return;
1516         }
1517         if (cmd != scmd->back) {
1518                 printk(KERN_WARNING "%s: "
1519                     "sense done for wrong command 0x%x\n",
1520                     sc->name, cmd->tag);
1521                 return;
1522         }
1523         if (cmd->state != UB_CMDST_SENSE) {
1524                 printk(KERN_WARNING "%s: sense done with bad cmd state %d\n",
1525                     sc->name, cmd->state);
1526                 return;
1527         }
1528
1529         /*
1530          * Ignoring scmd->act_len, because the buffer was pre-zeroed.
1531          */
1532         cmd->key = sense[2] & 0x0F;
1533         cmd->asc = sense[12];
1534         cmd->ascq = sense[13];
1535
1536         ub_scsi_urb_compl(sc, cmd);
1537 }
1538
1539 /*
1540  * Reset management
1541  */
1542
1543 static void ub_reset_enter(struct ub_dev *sc, int try)
1544 {
1545
1546         if (sc->reset) {
1547                 /* This happens often on multi-LUN devices. */
1548                 return;
1549         }
1550         sc->reset = try + 1;
1551
1552 #if 0 /* Not needed because the disconnect waits for us. */
1553         unsigned long flags;
1554         spin_lock_irqsave(&ub_lock, flags);
1555         sc->openc++;
1556         spin_unlock_irqrestore(&ub_lock, flags);
1557 #endif
1558
1559 #if 0 /* We let them stop themselves. */
1560         struct ub_lun *lun;
1561         list_for_each_entry(lun, &sc->luns, link) {
1562                 blk_stop_queue(lun->disk->queue);
1563         }
1564 #endif
1565
1566         schedule_work(&sc->reset_work);
1567 }
1568
1569 static void ub_reset_task(struct work_struct *work)
1570 {
1571         struct ub_dev *sc = container_of(work, struct ub_dev, reset_work);
1572         unsigned long flags;
1573         struct ub_lun *lun;
1574         int rc;
1575
1576         if (!sc->reset) {
1577                 printk(KERN_WARNING "%s: Running reset unrequested\n",
1578                     sc->name);
1579                 return;
1580         }
1581
1582         if (atomic_read(&sc->poison)) {
1583                 ;
1584         } else if ((sc->reset & 1) == 0) {
1585                 ub_sync_reset(sc);
1586                 msleep(700);    /* usb-storage sleeps 6s (!) */
1587                 ub_probe_clear_stall(sc, sc->recv_bulk_pipe);
1588                 ub_probe_clear_stall(sc, sc->send_bulk_pipe);
1589         } else if (sc->dev->actconfig->desc.bNumInterfaces != 1) {
1590                 ;
1591         } else {
1592                 rc = usb_lock_device_for_reset(sc->dev, sc->intf);
1593                 if (rc < 0) {
1594                         printk(KERN_NOTICE
1595                             "%s: usb_lock_device_for_reset failed (%d)\n",
1596                             sc->name, rc);
1597                 } else {
1598                         rc = usb_reset_device(sc->dev);
1599                         if (rc < 0) {
1600                                 printk(KERN_NOTICE "%s: "
1601                                     "usb_lock_device_for_reset failed (%d)\n",
1602                                     sc->name, rc);
1603                         }
1604                         usb_unlock_device(sc->dev);
1605                 }
1606         }
1607
1608         /*
1609          * In theory, no commands can be running while reset is active,
1610          * so nobody can ask for another reset, and so we do not need any
1611          * queues of resets or anything. We do need a spinlock though,
1612          * to interact with block layer.
1613          */
1614         spin_lock_irqsave(sc->lock, flags);
1615         sc->reset = 0;
1616         tasklet_schedule(&sc->tasklet);
1617         list_for_each_entry(lun, &sc->luns, link) {
1618                 blk_start_queue(lun->disk->queue);
1619         }
1620         wake_up(&sc->reset_wait);
1621         spin_unlock_irqrestore(sc->lock, flags);
1622 }
1623
1624 /*
1625  * XXX Reset brackets are too much hassle to implement, so just stub them
1626  * in order to prevent forced unbinding (which deadlocks solid when our
1627  * ->disconnect method waits for the reset to complete and this kills keventd).
1628  *
1629  * XXX Tell Alan to move usb_unlock_device inside of usb_reset_device,
1630  * or else the post_reset is invoked, and restats I/O on a locked device.
1631  */
1632 static int ub_pre_reset(struct usb_interface *iface) {
1633         return 0;
1634 }
1635
1636 static int ub_post_reset(struct usb_interface *iface) {
1637         return 0;
1638 }
1639
1640 /*
1641  * This is called from a process context.
1642  */
1643 static void ub_revalidate(struct ub_dev *sc, struct ub_lun *lun)
1644 {
1645
1646         lun->readonly = 0;      /* XXX Query this from the device */
1647
1648         lun->capacity.nsec = 0;
1649         lun->capacity.bsize = 512;
1650         lun->capacity.bshift = 0;
1651
1652         if (ub_sync_tur(sc, lun) != 0)
1653                 return;                 /* Not ready */
1654         lun->changed = 0;
1655
1656         if (ub_sync_read_cap(sc, lun, &lun->capacity) != 0) {
1657                 /*
1658                  * The retry here means something is wrong, either with the
1659                  * device, with the transport, or with our code.
1660                  * We keep this because sd.c has retries for capacity.
1661                  */
1662                 if (ub_sync_read_cap(sc, lun, &lun->capacity) != 0) {
1663                         lun->capacity.nsec = 0;
1664                         lun->capacity.bsize = 512;
1665                         lun->capacity.bshift = 0;
1666                 }
1667         }
1668 }
1669
1670 /*
1671  * The open funcion.
1672  * This is mostly needed to keep refcounting, but also to support
1673  * media checks on removable media drives.
1674  */
1675 static int ub_bd_open(struct block_device *bdev, fmode_t mode)
1676 {
1677         struct ub_lun *lun = bdev->bd_disk->private_data;
1678         struct ub_dev *sc = lun->udev;
1679         unsigned long flags;
1680         int rc;
1681
1682         spin_lock_irqsave(&ub_lock, flags);
1683         if (atomic_read(&sc->poison)) {
1684                 spin_unlock_irqrestore(&ub_lock, flags);
1685                 return -ENXIO;
1686         }
1687         sc->openc++;
1688         spin_unlock_irqrestore(&ub_lock, flags);
1689
1690         if (lun->removable || lun->readonly)
1691                 check_disk_change(bdev);
1692
1693         /*
1694          * The sd.c considers ->media_present and ->changed not equivalent,
1695          * under some pretty murky conditions (a failure of READ CAPACITY).
1696          * We may need it one day.
1697          */
1698         if (lun->removable && lun->changed && !(mode & FMODE_NDELAY)) {
1699                 rc = -ENOMEDIUM;
1700                 goto err_open;
1701         }
1702
1703         if (lun->readonly && (mode & FMODE_WRITE)) {
1704                 rc = -EROFS;
1705                 goto err_open;
1706         }
1707
1708         return 0;
1709
1710 err_open:
1711         ub_put(sc);
1712         return rc;
1713 }
1714
1715 static int ub_bd_unlocked_open(struct block_device *bdev, fmode_t mode)
1716 {
1717         int ret;
1718
1719         mutex_lock(&ub_mutex);
1720         ret = ub_bd_open(bdev, mode);
1721         mutex_unlock(&ub_mutex);
1722
1723         return ret;
1724 }
1725
1726
1727 /*
1728  */
1729 static int ub_bd_release(struct gendisk *disk, fmode_t mode)
1730 {
1731         struct ub_lun *lun = disk->private_data;
1732         struct ub_dev *sc = lun->udev;
1733
1734         mutex_lock(&ub_mutex);
1735         ub_put(sc);
1736         mutex_unlock(&ub_mutex);
1737
1738         return 0;
1739 }
1740
1741 /*
1742  * The ioctl interface.
1743  */
1744 static int ub_bd_ioctl(struct block_device *bdev, fmode_t mode,
1745     unsigned int cmd, unsigned long arg)
1746 {
1747         void __user *usermem = (void __user *) arg;
1748         int ret;
1749
1750         mutex_lock(&ub_mutex);
1751         ret = scsi_cmd_blk_ioctl(bdev, mode, cmd, usermem);
1752         mutex_unlock(&ub_mutex);
1753
1754         return ret;
1755 }
1756
1757 /*
1758  * This is called by check_disk_change if we reported a media change.
1759  * The main onjective here is to discover the features of the media such as
1760  * the capacity, read-only status, etc. USB storage generally does not
1761  * need to be spun up, but if we needed it, this would be the place.
1762  *
1763  * This call can sleep.
1764  *
1765  * The return code is not used.
1766  */
1767 static int ub_bd_revalidate(struct gendisk *disk)
1768 {
1769         struct ub_lun *lun = disk->private_data;
1770
1771         ub_revalidate(lun->udev, lun);
1772
1773         /* XXX Support sector size switching like in sr.c */
1774         blk_queue_logical_block_size(disk->queue, lun->capacity.bsize);
1775         set_capacity(disk, lun->capacity.nsec);
1776         // set_disk_ro(sdkp->disk, lun->readonly);
1777
1778         return 0;
1779 }
1780
1781 /*
1782  * The check is called by the block layer to verify if the media
1783  * is still available. It is supposed to be harmless, lightweight and
1784  * non-intrusive in case the media was not changed.
1785  *
1786  * This call can sleep.
1787  *
1788  * The return code is bool!
1789  */
1790 static unsigned int ub_bd_check_events(struct gendisk *disk,
1791                                        unsigned int clearing)
1792 {
1793         struct ub_lun *lun = disk->private_data;
1794
1795         if (!lun->removable)
1796                 return 0;
1797
1798         /*
1799          * We clean checks always after every command, so this is not
1800          * as dangerous as it looks. If the TEST_UNIT_READY fails here,
1801          * the device is actually not ready with operator or software
1802          * intervention required. One dangerous item might be a drive which
1803          * spins itself down, and come the time to write dirty pages, this
1804          * will fail, then block layer discards the data. Since we never
1805          * spin drives up, such devices simply cannot be used with ub anyway.
1806          */
1807         if (ub_sync_tur(lun->udev, lun) != 0) {
1808                 lun->changed = 1;
1809                 return DISK_EVENT_MEDIA_CHANGE;
1810         }
1811
1812         return lun->changed ? DISK_EVENT_MEDIA_CHANGE : 0;
1813 }
1814
1815 static const struct block_device_operations ub_bd_fops = {
1816         .owner          = THIS_MODULE,
1817         .open           = ub_bd_unlocked_open,
1818         .release        = ub_bd_release,
1819         .ioctl          = ub_bd_ioctl,
1820         .check_events   = ub_bd_check_events,
1821         .revalidate_disk = ub_bd_revalidate,
1822 };
1823
1824 /*
1825  * Common ->done routine for commands executed synchronously.
1826  */
1827 static void ub_probe_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1828 {
1829         struct completion *cop = cmd->back;
1830         complete(cop);
1831 }
1832
1833 /*
1834  * Test if the device has a check condition on it, synchronously.
1835  */
1836 static int ub_sync_tur(struct ub_dev *sc, struct ub_lun *lun)
1837 {
1838         struct ub_scsi_cmd *cmd;
1839         enum { ALLOC_SIZE = sizeof(struct ub_scsi_cmd) };
1840         unsigned long flags;
1841         struct completion compl;
1842         int rc;
1843
1844         init_completion(&compl);
1845
1846         rc = -ENOMEM;
1847         if ((cmd = kzalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
1848                 goto err_alloc;
1849
1850         cmd->cdb[0] = TEST_UNIT_READY;
1851         cmd->cdb_len = 6;
1852         cmd->dir = UB_DIR_NONE;
1853         cmd->state = UB_CMDST_INIT;
1854         cmd->lun = lun;                 /* This may be NULL, but that's ok */
1855         cmd->done = ub_probe_done;
1856         cmd->back = &compl;
1857
1858         spin_lock_irqsave(sc->lock, flags);
1859         cmd->tag = sc->tagcnt++;
1860
1861         rc = ub_submit_scsi(sc, cmd);
1862         spin_unlock_irqrestore(sc->lock, flags);
1863
1864         if (rc != 0)
1865                 goto err_submit;
1866
1867         wait_for_completion(&compl);
1868
1869         rc = cmd->error;
1870
1871         if (rc == -EIO && cmd->key != 0)        /* Retries for benh's key */
1872                 rc = cmd->key;
1873
1874 err_submit:
1875         kfree(cmd);
1876 err_alloc:
1877         return rc;
1878 }
1879
1880 /*
1881  * Read the SCSI capacity synchronously (for probing).
1882  */
1883 static int ub_sync_read_cap(struct ub_dev *sc, struct ub_lun *lun,
1884     struct ub_capacity *ret)
1885 {
1886         struct ub_scsi_cmd *cmd;
1887         struct scatterlist *sg;
1888         char *p;
1889         enum { ALLOC_SIZE = sizeof(struct ub_scsi_cmd) + 8 };
1890         unsigned long flags;
1891         unsigned int bsize, shift;
1892         unsigned long nsec;
1893         struct completion compl;
1894         int rc;
1895
1896         init_completion(&compl);
1897
1898         rc = -ENOMEM;
1899         if ((cmd = kzalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
1900                 goto err_alloc;
1901         p = (char *)cmd + sizeof(struct ub_scsi_cmd);
1902
1903         cmd->cdb[0] = 0x25;
1904         cmd->cdb_len = 10;
1905         cmd->dir = UB_DIR_READ;
1906         cmd->state = UB_CMDST_INIT;
1907         cmd->nsg = 1;
1908         sg = &cmd->sgv[0];
1909         sg_init_table(sg, UB_MAX_REQ_SG);
1910         sg_set_page(sg, virt_to_page(p), 8, (unsigned long)p & (PAGE_SIZE-1));
1911         cmd->len = 8;
1912         cmd->lun = lun;
1913         cmd->done = ub_probe_done;
1914         cmd->back = &compl;
1915
1916         spin_lock_irqsave(sc->lock, flags);
1917         cmd->tag = sc->tagcnt++;
1918
1919         rc = ub_submit_scsi(sc, cmd);
1920         spin_unlock_irqrestore(sc->lock, flags);
1921
1922         if (rc != 0)
1923                 goto err_submit;
1924
1925         wait_for_completion(&compl);
1926
1927         if (cmd->error != 0) {
1928                 rc = -EIO;
1929                 goto err_read;
1930         }
1931         if (cmd->act_len != 8) {
1932                 rc = -EIO;
1933                 goto err_read;
1934         }
1935
1936         /* sd.c special-cases sector size of 0 to mean 512. Needed? Safe? */
1937         nsec = be32_to_cpu(*(__be32 *)p) + 1;
1938         bsize = be32_to_cpu(*(__be32 *)(p + 4));
1939         switch (bsize) {
1940         case 512:       shift = 0;      break;
1941         case 1024:      shift = 1;      break;
1942         case 2048:      shift = 2;      break;
1943         case 4096:      shift = 3;      break;
1944         default:
1945                 rc = -EDOM;
1946                 goto err_inv_bsize;
1947         }
1948
1949         ret->bsize = bsize;
1950         ret->bshift = shift;
1951         ret->nsec = nsec << shift;
1952         rc = 0;
1953
1954 err_inv_bsize:
1955 err_read:
1956 err_submit:
1957         kfree(cmd);
1958 err_alloc:
1959         return rc;
1960 }
1961
1962 /*
1963  */
1964 static void ub_probe_urb_complete(struct urb *urb)
1965 {
1966         struct completion *cop = urb->context;
1967         complete(cop);
1968 }
1969
1970 static void ub_probe_timeout(unsigned long arg)
1971 {
1972         struct completion *cop = (struct completion *) arg;
1973         complete(cop);
1974 }
1975
1976 /*
1977  * Reset with a Bulk reset.
1978  */
1979 static int ub_sync_reset(struct ub_dev *sc)
1980 {
1981         int ifnum = sc->intf->cur_altsetting->desc.bInterfaceNumber;
1982         struct usb_ctrlrequest *cr;
1983         struct completion compl;
1984         struct timer_list timer;
1985         int rc;
1986
1987         init_completion(&compl);
1988
1989         cr = &sc->work_cr;
1990         cr->bRequestType = USB_TYPE_CLASS | USB_RECIP_INTERFACE;
1991         cr->bRequest = US_BULK_RESET_REQUEST;
1992         cr->wValue = cpu_to_le16(0);
1993         cr->wIndex = cpu_to_le16(ifnum);
1994         cr->wLength = cpu_to_le16(0);
1995
1996         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->send_ctrl_pipe,
1997             (unsigned char*) cr, NULL, 0, ub_probe_urb_complete, &compl);
1998
1999         if ((rc = usb_submit_urb(&sc->work_urb, GFP_KERNEL)) != 0) {
2000                 printk(KERN_WARNING
2001                      "%s: Unable to submit a bulk reset (%d)\n", sc->name, rc);
2002                 return rc;
2003         }
2004
2005         init_timer(&timer);
2006         timer.function = ub_probe_timeout;
2007         timer.data = (unsigned long) &compl;
2008         timer.expires = jiffies + UB_CTRL_TIMEOUT;
2009         add_timer(&timer);
2010
2011         wait_for_completion(&compl);
2012
2013         del_timer_sync(&timer);
2014         usb_kill_urb(&sc->work_urb);
2015
2016         return sc->work_urb.status;
2017 }
2018
2019 /*
2020  * Get number of LUNs by the way of Bulk GetMaxLUN command.
2021  */
2022 static int ub_sync_getmaxlun(struct ub_dev *sc)
2023 {
2024         int ifnum = sc->intf->cur_altsetting->desc.bInterfaceNumber;
2025         unsigned char *p;
2026         enum { ALLOC_SIZE = 1 };
2027         struct usb_ctrlrequest *cr;
2028         struct completion compl;
2029         struct timer_list timer;
2030         int nluns;
2031         int rc;
2032
2033         init_completion(&compl);
2034
2035         rc = -ENOMEM;
2036         if ((p = kmalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
2037                 goto err_alloc;
2038         *p = 55;
2039
2040         cr = &sc->work_cr;
2041         cr->bRequestType = USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE;
2042         cr->bRequest = US_BULK_GET_MAX_LUN;
2043         cr->wValue = cpu_to_le16(0);
2044         cr->wIndex = cpu_to_le16(ifnum);
2045         cr->wLength = cpu_to_le16(1);
2046
2047         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->recv_ctrl_pipe,
2048             (unsigned char*) cr, p, 1, ub_probe_urb_complete, &compl);
2049
2050         if ((rc = usb_submit_urb(&sc->work_urb, GFP_KERNEL)) != 0)
2051                 goto err_submit;
2052
2053         init_timer(&timer);
2054         timer.function = ub_probe_timeout;
2055         timer.data = (unsigned long) &compl;
2056         timer.expires = jiffies + UB_CTRL_TIMEOUT;
2057         add_timer(&timer);
2058
2059         wait_for_completion(&compl);
2060
2061         del_timer_sync(&timer);
2062         usb_kill_urb(&sc->work_urb);
2063
2064         if ((rc = sc->work_urb.status) < 0)
2065                 goto err_io;
2066
2067         if (sc->work_urb.actual_length != 1) {
2068                 nluns = 0;
2069         } else {
2070                 if ((nluns = *p) == 55) {
2071                         nluns = 0;
2072                 } else {
2073                         /* GetMaxLUN returns the maximum LUN number */
2074                         nluns += 1;
2075                         if (nluns > UB_MAX_LUNS)
2076                                 nluns = UB_MAX_LUNS;
2077                 }
2078         }
2079
2080         kfree(p);
2081         return nluns;
2082
2083 err_io:
2084 err_submit:
2085         kfree(p);
2086 err_alloc:
2087         return rc;
2088 }
2089
2090 /*
2091  * Clear initial stalls.
2092  */
2093 static int ub_probe_clear_stall(struct ub_dev *sc, int stalled_pipe)
2094 {
2095         int endp;
2096         struct usb_ctrlrequest *cr;
2097         struct completion compl;
2098         struct timer_list timer;
2099         int rc;
2100
2101         init_completion(&compl);
2102
2103         endp = usb_pipeendpoint(stalled_pipe);
2104         if (usb_pipein (stalled_pipe))
2105                 endp |= USB_DIR_IN;
2106
2107         cr = &sc->work_cr;
2108         cr->bRequestType = USB_RECIP_ENDPOINT;
2109         cr->bRequest = USB_REQ_CLEAR_FEATURE;
2110         cr->wValue = cpu_to_le16(USB_ENDPOINT_HALT);
2111         cr->wIndex = cpu_to_le16(endp);
2112         cr->wLength = cpu_to_le16(0);
2113
2114         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->send_ctrl_pipe,
2115             (unsigned char*) cr, NULL, 0, ub_probe_urb_complete, &compl);
2116
2117         if ((rc = usb_submit_urb(&sc->work_urb, GFP_KERNEL)) != 0) {
2118                 printk(KERN_WARNING
2119                      "%s: Unable to submit a probe clear (%d)\n", sc->name, rc);
2120                 return rc;
2121         }
2122
2123         init_timer(&timer);
2124         timer.function = ub_probe_timeout;
2125         timer.data = (unsigned long) &compl;
2126         timer.expires = jiffies + UB_CTRL_TIMEOUT;
2127         add_timer(&timer);
2128
2129         wait_for_completion(&compl);
2130
2131         del_timer_sync(&timer);
2132         usb_kill_urb(&sc->work_urb);
2133
2134         usb_reset_endpoint(sc->dev, endp);
2135
2136         return 0;
2137 }
2138
2139 /*
2140  * Get the pipe settings.
2141  */
2142 static int ub_get_pipes(struct ub_dev *sc, struct usb_device *dev,
2143     struct usb_interface *intf)
2144 {
2145         struct usb_host_interface *altsetting = intf->cur_altsetting;
2146         struct usb_endpoint_descriptor *ep_in = NULL;
2147         struct usb_endpoint_descriptor *ep_out = NULL;
2148         struct usb_endpoint_descriptor *ep;
2149         int i;
2150
2151         /*
2152          * Find the endpoints we need.
2153          * We are expecting a minimum of 2 endpoints - in and out (bulk).
2154          * We will ignore any others.
2155          */
2156         for (i = 0; i < altsetting->desc.bNumEndpoints; i++) {
2157                 ep = &altsetting->endpoint[i].desc;
2158
2159                 /* Is it a BULK endpoint? */
2160                 if (usb_endpoint_xfer_bulk(ep)) {
2161                         /* BULK in or out? */
2162                         if (usb_endpoint_dir_in(ep)) {
2163                                 if (ep_in == NULL)
2164                                         ep_in = ep;
2165                         } else {
2166                                 if (ep_out == NULL)
2167                                         ep_out = ep;
2168                         }
2169                 }
2170         }
2171
2172         if (ep_in == NULL || ep_out == NULL) {
2173                 printk(KERN_NOTICE "%s: failed endpoint check\n", sc->name);
2174                 return -ENODEV;
2175         }
2176
2177         /* Calculate and store the pipe values */
2178         sc->send_ctrl_pipe = usb_sndctrlpipe(dev, 0);
2179         sc->recv_ctrl_pipe = usb_rcvctrlpipe(dev, 0);
2180         sc->send_bulk_pipe = usb_sndbulkpipe(dev,
2181                 usb_endpoint_num(ep_out));
2182         sc->recv_bulk_pipe = usb_rcvbulkpipe(dev, 
2183                 usb_endpoint_num(ep_in));
2184
2185         return 0;
2186 }
2187
2188 /*
2189  * Probing is done in the process context, which allows us to cheat
2190  * and not to build a state machine for the discovery.
2191  */
2192 static int ub_probe(struct usb_interface *intf,
2193     const struct usb_device_id *dev_id)
2194 {
2195         struct ub_dev *sc;
2196         int nluns;
2197         int rc;
2198         int i;
2199
2200         if (usb_usual_check_type(dev_id, USB_US_TYPE_UB))
2201                 return -ENXIO;
2202
2203         rc = -ENOMEM;
2204         if ((sc = kzalloc(sizeof(struct ub_dev), GFP_KERNEL)) == NULL)
2205                 goto err_core;
2206         sc->lock = ub_next_lock();
2207         INIT_LIST_HEAD(&sc->luns);
2208         usb_init_urb(&sc->work_urb);
2209         tasklet_init(&sc->tasklet, ub_scsi_action, (unsigned long)sc);
2210         atomic_set(&sc->poison, 0);
2211         INIT_WORK(&sc->reset_work, ub_reset_task);
2212         init_waitqueue_head(&sc->reset_wait);
2213
2214         init_timer(&sc->work_timer);
2215         sc->work_timer.data = (unsigned long) sc;
2216         sc->work_timer.function = ub_urb_timeout;
2217
2218         ub_init_completion(&sc->work_done);
2219         sc->work_done.done = 1;         /* A little yuk, but oh well... */
2220
2221         sc->dev = interface_to_usbdev(intf);
2222         sc->intf = intf;
2223         // sc->ifnum = intf->cur_altsetting->desc.bInterfaceNumber;
2224         usb_set_intfdata(intf, sc);
2225         usb_get_dev(sc->dev);
2226         /*
2227          * Since we give the interface struct to the block level through
2228          * disk->driverfs_dev, we have to pin it. Otherwise, block_uevent
2229          * oopses on close after a disconnect (kernels 2.6.16 and up).
2230          */
2231         usb_get_intf(sc->intf);
2232
2233         snprintf(sc->name, 12, DRV_NAME "(%d.%d)",
2234             sc->dev->bus->busnum, sc->dev->devnum);
2235
2236         /* XXX Verify that we can handle the device (from descriptors) */
2237
2238         if (ub_get_pipes(sc, sc->dev, intf) != 0)
2239                 goto err_dev_desc;
2240
2241         /*
2242          * At this point, all USB initialization is done, do upper layer.
2243          * We really hate halfway initialized structures, so from the
2244          * invariants perspective, this ub_dev is fully constructed at
2245          * this point.
2246          */
2247
2248         /*
2249          * This is needed to clear toggles. It is a problem only if we do
2250          * `rmmod ub && modprobe ub` without disconnects, but we like that.
2251          */
2252 #if 0 /* iPod Mini fails if we do this (big white iPod works) */
2253         ub_probe_clear_stall(sc, sc->recv_bulk_pipe);
2254         ub_probe_clear_stall(sc, sc->send_bulk_pipe);
2255 #endif
2256
2257         /*
2258          * The way this is used by the startup code is a little specific.
2259          * A SCSI check causes a USB stall. Our common case code sees it
2260          * and clears the check, after which the device is ready for use.
2261          * But if a check was not present, any command other than
2262          * TEST_UNIT_READY ends with a lockup (including REQUEST_SENSE).
2263          *
2264          * If we neglect to clear the SCSI check, the first real command fails
2265          * (which is the capacity readout). We clear that and retry, but why
2266          * causing spurious retries for no reason.
2267          *
2268          * Revalidation may start with its own TEST_UNIT_READY, but that one
2269          * has to succeed, so we clear checks with an additional one here.
2270          * In any case it's not our business how revaliadation is implemented.
2271          */
2272         for (i = 0; i < 3; i++) {  /* Retries for the schwag key from KS'04 */
2273                 if ((rc = ub_sync_tur(sc, NULL)) <= 0) break;
2274                 if (rc != 0x6) break;
2275                 msleep(10);
2276         }
2277
2278         nluns = 1;
2279         for (i = 0; i < 3; i++) {
2280                 if ((rc = ub_sync_getmaxlun(sc)) < 0)
2281                         break;
2282                 if (rc != 0) {
2283                         nluns = rc;
2284                         break;
2285                 }
2286                 msleep(100);
2287         }
2288
2289         for (i = 0; i < nluns; i++) {
2290                 ub_probe_lun(sc, i);
2291         }
2292         return 0;
2293
2294 err_dev_desc:
2295         usb_set_intfdata(intf, NULL);
2296         usb_put_intf(sc->intf);
2297         usb_put_dev(sc->dev);
2298         kfree(sc);
2299 err_core:
2300         return rc;
2301 }
2302
2303 static int ub_probe_lun(struct ub_dev *sc, int lnum)
2304 {
2305         struct ub_lun *lun;
2306         struct request_queue *q;
2307         struct gendisk *disk;
2308         int rc;
2309
2310         rc = -ENOMEM;
2311         if ((lun = kzalloc(sizeof(struct ub_lun), GFP_KERNEL)) == NULL)
2312                 goto err_alloc;
2313         lun->num = lnum;
2314
2315         rc = -ENOSR;
2316         if ((lun->id = ub_id_get()) == -1)
2317                 goto err_id;
2318
2319         lun->udev = sc;
2320
2321         snprintf(lun->name, 16, DRV_NAME "%c(%d.%d.%d)",
2322             lun->id + 'a', sc->dev->bus->busnum, sc->dev->devnum, lun->num);
2323
2324         lun->removable = 1;             /* XXX Query this from the device */
2325         lun->changed = 1;               /* ub_revalidate clears only */
2326         ub_revalidate(sc, lun);
2327
2328         rc = -ENOMEM;
2329         if ((disk = alloc_disk(UB_PARTS_PER_LUN)) == NULL)
2330                 goto err_diskalloc;
2331
2332         sprintf(disk->disk_name, DRV_NAME "%c", lun->id + 'a');
2333         disk->major = UB_MAJOR;
2334         disk->first_minor = lun->id * UB_PARTS_PER_LUN;
2335         disk->fops = &ub_bd_fops;
2336         disk->private_data = lun;
2337         disk->driverfs_dev = &sc->intf->dev;
2338
2339         rc = -ENOMEM;
2340         if ((q = blk_init_queue(ub_request_fn, sc->lock)) == NULL)
2341                 goto err_blkqinit;
2342
2343         disk->queue = q;
2344
2345         blk_queue_bounce_limit(q, BLK_BOUNCE_HIGH);
2346         blk_queue_max_segments(q, UB_MAX_REQ_SG);
2347         blk_queue_segment_boundary(q, 0xffffffff);      /* Dubious. */
2348         blk_queue_max_hw_sectors(q, UB_MAX_SECTORS);
2349         blk_queue_logical_block_size(q, lun->capacity.bsize);
2350
2351         lun->disk = disk;
2352         q->queuedata = lun;
2353         list_add(&lun->link, &sc->luns);
2354
2355         set_capacity(disk, lun->capacity.nsec);
2356         if (lun->removable)
2357                 disk->flags |= GENHD_FL_REMOVABLE;
2358
2359         add_disk(disk);
2360
2361         return 0;
2362
2363 err_blkqinit:
2364         put_disk(disk);
2365 err_diskalloc:
2366         ub_id_put(lun->id);
2367 err_id:
2368         kfree(lun);
2369 err_alloc:
2370         return rc;
2371 }
2372
2373 static void ub_disconnect(struct usb_interface *intf)
2374 {
2375         struct ub_dev *sc = usb_get_intfdata(intf);
2376         struct ub_lun *lun;
2377         unsigned long flags;
2378
2379         /*
2380          * Prevent ub_bd_release from pulling the rug from under us.
2381          * XXX This is starting to look like a kref.
2382          * XXX Why not to take this ref at probe time?
2383          */
2384         spin_lock_irqsave(&ub_lock, flags);
2385         sc->openc++;
2386         spin_unlock_irqrestore(&ub_lock, flags);
2387
2388         /*
2389          * Fence stall clearings, operations triggered by unlinkings and so on.
2390          * We do not attempt to unlink any URBs, because we do not trust the
2391          * unlink paths in HC drivers. Also, we get -84 upon disconnect anyway.
2392          */
2393         atomic_set(&sc->poison, 1);
2394
2395         /*
2396          * Wait for reset to end, if any.
2397          */
2398         wait_event(sc->reset_wait, !sc->reset);
2399
2400         /*
2401          * Blow away queued commands.
2402          *
2403          * Actually, this never works, because before we get here
2404          * the HCD terminates outstanding URB(s). It causes our
2405          * SCSI command queue to advance, commands fail to submit,
2406          * and the whole queue drains. So, we just use this code to
2407          * print warnings.
2408          */
2409         spin_lock_irqsave(sc->lock, flags);
2410         {
2411                 struct ub_scsi_cmd *cmd;
2412                 int cnt = 0;
2413                 while ((cmd = ub_cmdq_peek(sc)) != NULL) {
2414                         cmd->error = -ENOTCONN;
2415                         cmd->state = UB_CMDST_DONE;
2416                         ub_cmdq_pop(sc);
2417                         (*cmd->done)(sc, cmd);
2418                         cnt++;
2419                 }
2420                 if (cnt != 0) {
2421                         printk(KERN_WARNING "%s: "
2422                             "%d was queued after shutdown\n", sc->name, cnt);
2423                 }
2424         }
2425         spin_unlock_irqrestore(sc->lock, flags);
2426
2427         /*
2428          * Unregister the upper layer.
2429          */
2430         list_for_each_entry(lun, &sc->luns, link) {
2431                 del_gendisk(lun->disk);
2432                 /*
2433                  * I wish I could do:
2434                  *    queue_flag_set(QUEUE_FLAG_DEAD, q);
2435                  * As it is, we rely on our internal poisoning and let
2436                  * the upper levels to spin furiously failing all the I/O.
2437                  */
2438         }
2439
2440         /*
2441          * Testing for -EINPROGRESS is always a bug, so we are bending
2442          * the rules a little.
2443          */
2444         spin_lock_irqsave(sc->lock, flags);
2445         if (sc->work_urb.status == -EINPROGRESS) {      /* janitors: ignore */
2446                 printk(KERN_WARNING "%s: "
2447                     "URB is active after disconnect\n", sc->name);
2448         }
2449         spin_unlock_irqrestore(sc->lock, flags);
2450
2451         /*
2452          * There is virtually no chance that other CPU runs a timeout so long
2453          * after ub_urb_complete should have called del_timer, but only if HCD
2454          * didn't forget to deliver a callback on unlink.
2455          */
2456         del_timer_sync(&sc->work_timer);
2457
2458         /*
2459          * At this point there must be no commands coming from anyone
2460          * and no URBs left in transit.
2461          */
2462
2463         ub_put(sc);
2464 }
2465
2466 static struct usb_driver ub_driver = {
2467         .name =         "ub",
2468         .probe =        ub_probe,
2469         .disconnect =   ub_disconnect,
2470         .id_table =     ub_usb_ids,
2471         .pre_reset =    ub_pre_reset,
2472         .post_reset =   ub_post_reset,
2473 };
2474
2475 static int __init ub_init(void)
2476 {
2477         int rc;
2478         int i;
2479
2480         for (i = 0; i < UB_QLOCK_NUM; i++)
2481                 spin_lock_init(&ub_qlockv[i]);
2482
2483         if ((rc = register_blkdev(UB_MAJOR, DRV_NAME)) != 0)
2484                 goto err_regblkdev;
2485
2486         if ((rc = usb_register(&ub_driver)) != 0)
2487                 goto err_register;
2488
2489         usb_usual_set_present(USB_US_TYPE_UB);
2490         return 0;
2491
2492 err_register:
2493         unregister_blkdev(UB_MAJOR, DRV_NAME);
2494 err_regblkdev:
2495         return rc;
2496 }
2497
2498 static void __exit ub_exit(void)
2499 {
2500         usb_deregister(&ub_driver);
2501
2502         unregister_blkdev(UB_MAJOR, DRV_NAME);
2503         usb_usual_clear_present(USB_US_TYPE_UB);
2504 }
2505
2506 module_init(ub_init);
2507 module_exit(ub_exit);
2508
2509 MODULE_LICENSE("GPL");