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