8c2cc71327e3f47f9d04ae16927fcd972110f44a
[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 <scsi/scsi.h>
31
32 #define DRV_NAME "ub"
33
34 #define UB_MAJOR 180
35
36 /*
37  * The command state machine is the key model for understanding of this driver.
38  *
39  * The general rule is that all transitions are done towards the bottom
40  * of the diagram, thus preventing any loops.
41  *
42  * An exception to that is how the STAT state is handled. A counter allows it
43  * to be re-entered along the path marked with [C].
44  *
45  *       +--------+
46  *       ! INIT   !
47  *       +--------+
48  *           !
49  *        ub_scsi_cmd_start fails ->--------------------------------------\
50  *           !                                                            !
51  *           V                                                            !
52  *       +--------+                                                       !
53  *       ! CMD    !                                                       !
54  *       +--------+                                                       !
55  *           !                                            +--------+      !
56  *         was -EPIPE -->-------------------------------->! CLEAR  !      !
57  *           !                                            +--------+      !
58  *           !                                                !           !
59  *         was error -->------------------------------------- ! --------->\
60  *           !                                                !           !
61  *  /--<-- cmd->dir == NONE ?                                 !           !
62  *  !        !                                                !           !
63  *  !        V                                                !           !
64  *  !    +--------+                                           !           !
65  *  !    ! DATA   !                                           !           !
66  *  !    +--------+                                           !           !
67  *  !        !                           +---------+          !           !
68  *  !      was -EPIPE -->--------------->! CLR2STS !          !           !
69  *  !        !                           +---------+          !           !
70  *  !        !                                !               !           !
71  *  !        !                              was error -->---- ! --------->\
72  *  !      was error -->--------------------- ! ------------- ! --------->\
73  *  !        !                                !               !           !
74  *  !        V                                !               !           !
75  *  \--->+--------+                           !               !           !
76  *       ! STAT   !<--------------------------/               !           !
77  *  /--->+--------+                                           !           !
78  *  !        !                                                !           !
79  * [C]     was -EPIPE -->-----------\                         !           !
80  *  !        !                      !                         !           !
81  *  +<---- len == 0                 !                         !           !
82  *  !        !                      !                         !           !
83  *  !      was error -->--------------------------------------!---------->\
84  *  !        !                      !                         !           !
85  *  +<---- bad CSW                  !                         !           !
86  *  +<---- bad tag                  !                         !           !
87  *  !        !                      V                         !           !
88  *  !        !                 +--------+                     !           !
89  *  !        !                 ! CLRRS  !                     !           !
90  *  !        !                 +--------+                     !           !
91  *  !        !                      !                         !           !
92  *  \------- ! --------------------[C]--------\               !           !
93  *           !                                !               !           !
94  *         cmd->error---\                +--------+           !           !
95  *           !          +--------------->! SENSE  !<----------/           !
96  *         STAT_FAIL----/                +--------+                       !
97  *           !                                !                           V
98  *           !                                V                      +--------+
99  *           \--------------------------------\--------------------->! DONE   !
100  *                                                                   +--------+
101  */
102
103 /*
104  * This many LUNs per USB device.
105  * Every one of them takes a host, see UB_MAX_HOSTS.
106  */
107 #define UB_MAX_LUNS   9
108
109 /*
110  */
111
112 #define UB_PARTS_PER_LUN      8
113
114 #define UB_MAX_CDB_SIZE      16         /* Corresponds to Bulk */
115
116 #define UB_SENSE_SIZE  18
117
118 /*
119  */
120
121 /* command block wrapper */
122 struct bulk_cb_wrap {
123         __le32  Signature;              /* contains 'USBC' */
124         u32     Tag;                    /* unique per command id */
125         __le32  DataTransferLength;     /* size of data */
126         u8      Flags;                  /* direction in bit 0 */
127         u8      Lun;                    /* LUN */
128         u8      Length;                 /* of of the CDB */
129         u8      CDB[UB_MAX_CDB_SIZE];   /* max command */
130 };
131
132 #define US_BULK_CB_WRAP_LEN     31
133 #define US_BULK_CB_SIGN         0x43425355      /*spells out USBC */
134 #define US_BULK_FLAG_IN         1
135 #define US_BULK_FLAG_OUT        0
136
137 /* command status wrapper */
138 struct bulk_cs_wrap {
139         __le32  Signature;              /* should = 'USBS' */
140         u32     Tag;                    /* same as original command */
141         __le32  Residue;                /* amount not transferred */
142         u8      Status;                 /* see below */
143 };
144
145 #define US_BULK_CS_WRAP_LEN     13
146 #define US_BULK_CS_SIGN         0x53425355      /* spells out 'USBS' */
147 #define US_BULK_STAT_OK         0
148 #define US_BULK_STAT_FAIL       1
149 #define US_BULK_STAT_PHASE      2
150
151 /* bulk-only class specific requests */
152 #define US_BULK_RESET_REQUEST   0xff
153 #define US_BULK_GET_MAX_LUN     0xfe
154
155 /*
156  */
157 struct ub_dev;
158
159 #define UB_MAX_REQ_SG   9       /* cdrecord requires 32KB and maybe a header */
160 #define UB_MAX_SECTORS 64
161
162 /*
163  * A second is more than enough for a 32K transfer (UB_MAX_SECTORS)
164  * even if a webcam hogs the bus, but some devices need time to spin up.
165  */
166 #define UB_URB_TIMEOUT  (HZ*2)
167 #define UB_DATA_TIMEOUT (HZ*5)  /* ZIP does spin-ups in the data phase */
168 #define UB_STAT_TIMEOUT (HZ*5)  /* Same spinups and eject for a dataless cmd. */
169 #define UB_CTRL_TIMEOUT (HZ/2)  /* 500ms ought to be enough to clear a stall */
170
171 /*
172  * An instance of a SCSI command in transit.
173  */
174 #define UB_DIR_NONE     0
175 #define UB_DIR_READ     1
176 #define UB_DIR_ILLEGAL2 2
177 #define UB_DIR_WRITE    3
178
179 #define UB_DIR_CHAR(c)  (((c)==UB_DIR_WRITE)? 'w': \
180                          (((c)==UB_DIR_READ)? 'r': 'n'))
181
182 enum ub_scsi_cmd_state {
183         UB_CMDST_INIT,                  /* Initial state */
184         UB_CMDST_CMD,                   /* Command submitted */
185         UB_CMDST_DATA,                  /* Data phase */
186         UB_CMDST_CLR2STS,               /* Clearing before requesting status */
187         UB_CMDST_STAT,                  /* Status phase */
188         UB_CMDST_CLEAR,                 /* Clearing a stall (halt, actually) */
189         UB_CMDST_CLRRS,                 /* Clearing before retrying status */
190         UB_CMDST_SENSE,                 /* Sending Request Sense */
191         UB_CMDST_DONE                   /* Final state */
192 };
193
194 struct ub_scsi_cmd {
195         unsigned char cdb[UB_MAX_CDB_SIZE];
196         unsigned char cdb_len;
197
198         unsigned char dir;              /* 0 - none, 1 - read, 3 - write. */
199         enum ub_scsi_cmd_state state;
200         unsigned int tag;
201         struct ub_scsi_cmd *next;
202
203         int error;                      /* Return code - valid upon done */
204         unsigned int act_len;           /* Return size */
205         unsigned char key, asc, ascq;   /* May be valid if error==-EIO */
206
207         int stat_count;                 /* Retries getting status. */
208         unsigned int timeo;             /* jiffies until rq->timeout changes */
209
210         unsigned int len;               /* Requested length */
211         unsigned int current_sg;
212         unsigned int nsg;               /* sgv[nsg] */
213         struct scatterlist sgv[UB_MAX_REQ_SG];
214
215         struct ub_lun *lun;
216         void (*done)(struct ub_dev *, struct ub_scsi_cmd *);
217         void *back;
218 };
219
220 struct ub_request {
221         struct request *rq;
222         unsigned int current_try;
223         unsigned int nsg;               /* sgv[nsg] */
224         struct scatterlist sgv[UB_MAX_REQ_SG];
225 };
226
227 /*
228  */
229 struct ub_capacity {
230         unsigned long nsec;             /* Linux size - 512 byte sectors */
231         unsigned int bsize;             /* Linux hardsect_size */
232         unsigned int bshift;            /* Shift between 512 and hard sects */
233 };
234
235 /*
236  * This is a direct take-off from linux/include/completion.h
237  * The difference is that I do not wait on this thing, just poll.
238  * When I want to wait (ub_probe), I just use the stock completion.
239  *
240  * Note that INIT_COMPLETION takes no lock. It is correct. But why
241  * in the bloody hell that thing takes struct instead of pointer to struct
242  * is quite beyond me. I just copied it from the stock completion.
243  */
244 struct ub_completion {
245         unsigned int done;
246         spinlock_t lock;
247 };
248
249 static inline void ub_init_completion(struct ub_completion *x)
250 {
251         x->done = 0;
252         spin_lock_init(&x->lock);
253 }
254
255 #define UB_INIT_COMPLETION(x)   ((x).done = 0)
256
257 static void ub_complete(struct ub_completion *x)
258 {
259         unsigned long flags;
260
261         spin_lock_irqsave(&x->lock, flags);
262         x->done++;
263         spin_unlock_irqrestore(&x->lock, flags);
264 }
265
266 static int ub_is_completed(struct ub_completion *x)
267 {
268         unsigned long flags;
269         int ret;
270
271         spin_lock_irqsave(&x->lock, flags);
272         ret = x->done;
273         spin_unlock_irqrestore(&x->lock, flags);
274         return ret;
275 }
276
277 /*
278  */
279 struct ub_scsi_cmd_queue {
280         int qlen, qmax;
281         struct ub_scsi_cmd *head, *tail;
282 };
283
284 /*
285  * The block device instance (one per LUN).
286  */
287 struct ub_lun {
288         struct ub_dev *udev;
289         struct list_head link;
290         struct gendisk *disk;
291         int id;                         /* Host index */
292         int num;                        /* LUN number */
293         char name[16];
294
295         int changed;                    /* Media was changed */
296         int removable;
297         int readonly;
298
299         struct ub_request urq;
300
301         /* Use Ingo's mempool if or when we have more than one command. */
302         /*
303          * Currently we never need more than one command for the whole device.
304          * However, giving every LUN a command is a cheap and automatic way
305          * to enforce fairness between them.
306          */
307         int cmda[1];
308         struct ub_scsi_cmd cmdv[1];
309
310         struct ub_capacity capacity; 
311 };
312
313 /*
314  * The USB device instance.
315  */
316 struct ub_dev {
317         spinlock_t *lock;
318         atomic_t poison;                /* The USB device is disconnected */
319         int openc;                      /* protected by ub_lock! */
320                                         /* kref is too implicit for our taste */
321         int reset;                      /* Reset is running */
322         int bad_resid;
323         unsigned int tagcnt;
324         char name[12];
325         struct usb_device *dev;
326         struct usb_interface *intf;
327
328         struct list_head luns;
329
330         unsigned int send_bulk_pipe;    /* cached pipe values */
331         unsigned int recv_bulk_pipe;
332         unsigned int send_ctrl_pipe;
333         unsigned int recv_ctrl_pipe;
334
335         struct tasklet_struct tasklet;
336
337         struct ub_scsi_cmd_queue cmd_queue;
338         struct ub_scsi_cmd top_rqs_cmd; /* REQUEST SENSE */
339         unsigned char top_sense[UB_SENSE_SIZE];
340
341         struct ub_completion work_done;
342         struct urb work_urb;
343         struct timer_list work_timer;
344         int last_pipe;                  /* What might need clearing */
345         __le32 signature;               /* Learned signature */
346         struct bulk_cb_wrap work_bcb;
347         struct bulk_cs_wrap work_bcs;
348         struct usb_ctrlrequest work_cr;
349
350         struct work_struct reset_work;
351         wait_queue_head_t reset_wait;
352 };
353
354 /*
355  */
356 static void ub_cleanup(struct ub_dev *sc);
357 static int ub_request_fn_1(struct ub_lun *lun, struct request *rq);
358 static void ub_cmd_build_block(struct ub_dev *sc, struct ub_lun *lun,
359     struct ub_scsi_cmd *cmd, struct ub_request *urq);
360 static void ub_cmd_build_packet(struct ub_dev *sc, struct ub_lun *lun,
361     struct ub_scsi_cmd *cmd, struct ub_request *urq);
362 static void ub_rw_cmd_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
363 static void ub_end_rq(struct request *rq, unsigned int status,
364     unsigned int cmd_len);
365 static int ub_rw_cmd_retry(struct ub_dev *sc, struct ub_lun *lun,
366     struct ub_request *urq, struct ub_scsi_cmd *cmd);
367 static int ub_submit_scsi(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
368 static void ub_urb_complete(struct urb *urb);
369 static void ub_scsi_action(unsigned long _dev);
370 static void ub_scsi_dispatch(struct ub_dev *sc);
371 static void ub_scsi_urb_compl(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
372 static void ub_data_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
373 static void ub_state_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd, int rc);
374 static int __ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
375 static void ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
376 static void ub_state_stat_counted(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
377 static void ub_state_sense(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
378 static int ub_submit_clear_stall(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
379     int stalled_pipe);
380 static void ub_top_sense_done(struct ub_dev *sc, struct ub_scsi_cmd *scmd);
381 static void ub_reset_enter(struct ub_dev *sc, int try);
382 static void ub_reset_task(struct work_struct *work);
383 static int ub_sync_tur(struct ub_dev *sc, struct ub_lun *lun);
384 static int ub_sync_read_cap(struct ub_dev *sc, struct ub_lun *lun,
385     struct ub_capacity *ret);
386 static int ub_sync_reset(struct ub_dev *sc);
387 static int ub_probe_clear_stall(struct ub_dev *sc, int stalled_pipe);
388 static int ub_probe_lun(struct ub_dev *sc, int lnum);
389
390 /*
391  */
392 #ifdef CONFIG_USB_LIBUSUAL
393
394 #define ub_usb_ids  usb_storage_usb_ids
395 #else
396
397 static struct usb_device_id ub_usb_ids[] = {
398         { USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, US_SC_SCSI, US_PR_BULK) },
399         { }
400 };
401
402 MODULE_DEVICE_TABLE(usb, ub_usb_ids);
403 #endif /* CONFIG_USB_LIBUSUAL */
404
405 /*
406  * Find me a way to identify "next free minor" for add_disk(),
407  * and the array disappears the next day. However, the number of
408  * hosts has something to do with the naming and /proc/partitions.
409  * This has to be thought out in detail before changing.
410  * If UB_MAX_HOST was 1000, we'd use a bitmap. Or a better data structure.
411  */
412 #define UB_MAX_HOSTS  26
413 static char ub_hostv[UB_MAX_HOSTS];
414
415 #define UB_QLOCK_NUM 5
416 static spinlock_t ub_qlockv[UB_QLOCK_NUM];
417 static int ub_qlock_next = 0;
418
419 static DEFINE_SPINLOCK(ub_lock);        /* Locks globals and ->openc */
420
421 /*
422  * The id allocator.
423  *
424  * This also stores the host for indexing by minor, which is somewhat dirty.
425  */
426 static int ub_id_get(void)
427 {
428         unsigned long flags;
429         int i;
430
431         spin_lock_irqsave(&ub_lock, flags);
432         for (i = 0; i < UB_MAX_HOSTS; i++) {
433                 if (ub_hostv[i] == 0) {
434                         ub_hostv[i] = 1;
435                         spin_unlock_irqrestore(&ub_lock, flags);
436                         return i;
437                 }
438         }
439         spin_unlock_irqrestore(&ub_lock, flags);
440         return -1;
441 }
442
443 static void ub_id_put(int id)
444 {
445         unsigned long flags;
446
447         if (id < 0 || id >= UB_MAX_HOSTS) {
448                 printk(KERN_ERR DRV_NAME ": bad host ID %d\n", id);
449                 return;
450         }
451
452         spin_lock_irqsave(&ub_lock, flags);
453         if (ub_hostv[id] == 0) {
454                 spin_unlock_irqrestore(&ub_lock, flags);
455                 printk(KERN_ERR DRV_NAME ": freeing free host ID %d\n", id);
456                 return;
457         }
458         ub_hostv[id] = 0;
459         spin_unlock_irqrestore(&ub_lock, flags);
460 }
461
462 /*
463  * This is necessitated by the fact that blk_cleanup_queue does not
464  * necesserily destroy the queue. Instead, it may merely decrease q->refcnt.
465  * Since our blk_init_queue() passes a spinlock common with ub_dev,
466  * we have life time issues when ub_cleanup frees ub_dev.
467  */
468 static spinlock_t *ub_next_lock(void)
469 {
470         unsigned long flags;
471         spinlock_t *ret;
472
473         spin_lock_irqsave(&ub_lock, flags);
474         ret = &ub_qlockv[ub_qlock_next];
475         ub_qlock_next = (ub_qlock_next + 1) % UB_QLOCK_NUM;
476         spin_unlock_irqrestore(&ub_lock, flags);
477         return ret;
478 }
479
480 /*
481  * Downcount for deallocation. This rides on two assumptions:
482  *  - once something is poisoned, its refcount cannot grow
483  *  - opens cannot happen at this time (del_gendisk was done)
484  * If the above is true, we can drop the lock, which we need for
485  * blk_cleanup_queue(): the silly thing may attempt to sleep.
486  * [Actually, it never needs to sleep for us, but it calls might_sleep()]
487  */
488 static void ub_put(struct ub_dev *sc)
489 {
490         unsigned long flags;
491
492         spin_lock_irqsave(&ub_lock, flags);
493         --sc->openc;
494         if (sc->openc == 0 && atomic_read(&sc->poison)) {
495                 spin_unlock_irqrestore(&ub_lock, flags);
496                 ub_cleanup(sc);
497         } else {
498                 spin_unlock_irqrestore(&ub_lock, flags);
499         }
500 }
501
502 /*
503  * Final cleanup and deallocation.
504  */
505 static void ub_cleanup(struct ub_dev *sc)
506 {
507         struct list_head *p;
508         struct ub_lun *lun;
509         struct request_queue *q;
510
511         while (!list_empty(&sc->luns)) {
512                 p = sc->luns.next;
513                 lun = list_entry(p, struct ub_lun, link);
514                 list_del(p);
515
516                 /* I don't think queue can be NULL. But... Stolen from sx8.c */
517                 if ((q = lun->disk->queue) != NULL)
518                         blk_cleanup_queue(q);
519                 /*
520                  * If we zero disk->private_data BEFORE put_disk, we have
521                  * to check for NULL all over the place in open, release,
522                  * check_media and revalidate, because the block level
523                  * semaphore is well inside the put_disk.
524                  * But we cannot zero after the call, because *disk is gone.
525                  * The sd.c is blatantly racy in this area.
526                  */
527                 /* disk->private_data = NULL; */
528                 put_disk(lun->disk);
529                 lun->disk = NULL;
530
531                 ub_id_put(lun->id);
532                 kfree(lun);
533         }
534
535         usb_set_intfdata(sc->intf, NULL);
536         usb_put_intf(sc->intf);
537         usb_put_dev(sc->dev);
538         kfree(sc);
539 }
540
541 /*
542  * The "command allocator".
543  */
544 static struct ub_scsi_cmd *ub_get_cmd(struct ub_lun *lun)
545 {
546         struct ub_scsi_cmd *ret;
547
548         if (lun->cmda[0])
549                 return NULL;
550         ret = &lun->cmdv[0];
551         lun->cmda[0] = 1;
552         return ret;
553 }
554
555 static void ub_put_cmd(struct ub_lun *lun, struct ub_scsi_cmd *cmd)
556 {
557         if (cmd != &lun->cmdv[0]) {
558                 printk(KERN_WARNING "%s: releasing a foreign cmd %p\n",
559                     lun->name, cmd);
560                 return;
561         }
562         if (!lun->cmda[0]) {
563                 printk(KERN_WARNING "%s: releasing a free cmd\n", lun->name);
564                 return;
565         }
566         lun->cmda[0] = 0;
567 }
568
569 /*
570  * The command queue.
571  */
572 static void ub_cmdq_add(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
573 {
574         struct ub_scsi_cmd_queue *t = &sc->cmd_queue;
575
576         if (t->qlen++ == 0) {
577                 t->head = cmd;
578                 t->tail = cmd;
579         } else {
580                 t->tail->next = cmd;
581                 t->tail = cmd;
582         }
583
584         if (t->qlen > t->qmax)
585                 t->qmax = t->qlen;
586 }
587
588 static void ub_cmdq_insert(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
589 {
590         struct ub_scsi_cmd_queue *t = &sc->cmd_queue;
591
592         if (t->qlen++ == 0) {
593                 t->head = cmd;
594                 t->tail = cmd;
595         } else {
596                 cmd->next = t->head;
597                 t->head = cmd;
598         }
599
600         if (t->qlen > t->qmax)
601                 t->qmax = t->qlen;
602 }
603
604 static struct ub_scsi_cmd *ub_cmdq_pop(struct ub_dev *sc)
605 {
606         struct ub_scsi_cmd_queue *t = &sc->cmd_queue;
607         struct ub_scsi_cmd *cmd;
608
609         if (t->qlen == 0)
610                 return NULL;
611         if (--t->qlen == 0)
612                 t->tail = NULL;
613         cmd = t->head;
614         t->head = cmd->next;
615         cmd->next = NULL;
616         return cmd;
617 }
618
619 #define ub_cmdq_peek(sc)  ((sc)->cmd_queue.head)
620
621 /*
622  * The request function is our main entry point
623  */
624
625 static void ub_request_fn(struct request_queue *q)
626 {
627         struct ub_lun *lun = q->queuedata;
628         struct request *rq;
629
630         while ((rq = elv_next_request(q)) != NULL) {
631                 if (ub_request_fn_1(lun, rq) != 0) {
632                         blk_stop_queue(q);
633                         break;
634                 }
635         }
636 }
637
638 static int ub_request_fn_1(struct ub_lun *lun, struct request *rq)
639 {
640         struct ub_dev *sc = lun->udev;
641         struct ub_scsi_cmd *cmd;
642         struct ub_request *urq;
643         int n_elem;
644
645         if (atomic_read(&sc->poison)) {
646                 blkdev_dequeue_request(rq);
647                 ub_end_rq(rq, DID_NO_CONNECT << 16, blk_rq_bytes(rq));
648                 return 0;
649         }
650
651         if (lun->changed && !blk_pc_request(rq)) {
652                 blkdev_dequeue_request(rq);
653                 ub_end_rq(rq, SAM_STAT_CHECK_CONDITION, blk_rq_bytes(rq));
654                 return 0;
655         }
656
657         if (lun->urq.rq != NULL)
658                 return -1;
659         if ((cmd = ub_get_cmd(lun)) == NULL)
660                 return -1;
661         memset(cmd, 0, sizeof(struct ub_scsi_cmd));
662
663         blkdev_dequeue_request(rq);
664
665         urq = &lun->urq;
666         memset(urq, 0, sizeof(struct ub_request));
667         urq->rq = rq;
668
669         /*
670          * get scatterlist from block layer
671          */
672         sg_init_table(&urq->sgv[0], UB_MAX_REQ_SG);
673         n_elem = blk_rq_map_sg(lun->disk->queue, rq, &urq->sgv[0]);
674         if (n_elem < 0) {
675                 /* Impossible, because blk_rq_map_sg should not hit ENOMEM. */
676                 printk(KERN_INFO "%s: failed request map (%d)\n",
677                     lun->name, n_elem);
678                 goto drop;
679         }
680         if (n_elem > UB_MAX_REQ_SG) {   /* Paranoia */
681                 printk(KERN_WARNING "%s: request with %d segments\n",
682                     lun->name, n_elem);
683                 goto drop;
684         }
685         urq->nsg = n_elem;
686
687         if (blk_pc_request(rq)) {
688                 ub_cmd_build_packet(sc, lun, cmd, urq);
689         } else {
690                 ub_cmd_build_block(sc, lun, cmd, urq);
691         }
692         cmd->state = UB_CMDST_INIT;
693         cmd->lun = lun;
694         cmd->done = ub_rw_cmd_done;
695         cmd->back = urq;
696
697         cmd->tag = sc->tagcnt++;
698         if (ub_submit_scsi(sc, cmd) != 0)
699                 goto drop;
700
701         return 0;
702
703 drop:
704         ub_put_cmd(lun, cmd);
705         ub_end_rq(rq, DID_ERROR << 16, blk_rq_bytes(rq));
706         return 0;
707 }
708
709 static void ub_cmd_build_block(struct ub_dev *sc, struct ub_lun *lun,
710     struct ub_scsi_cmd *cmd, struct ub_request *urq)
711 {
712         struct request *rq = urq->rq;
713         unsigned int block, nblks;
714
715         if (rq_data_dir(rq) == WRITE)
716                 cmd->dir = UB_DIR_WRITE;
717         else
718                 cmd->dir = UB_DIR_READ;
719
720         cmd->nsg = urq->nsg;
721         memcpy(cmd->sgv, urq->sgv, sizeof(struct scatterlist) * cmd->nsg);
722
723         /*
724          * build the command
725          *
726          * The call to blk_queue_hardsect_size() guarantees that request
727          * is aligned, but it is given in terms of 512 byte units, always.
728          */
729         block = rq->sector >> lun->capacity.bshift;
730         nblks = rq->nr_sectors >> lun->capacity.bshift;
731
732         cmd->cdb[0] = (cmd->dir == UB_DIR_READ)? READ_10: WRITE_10;
733         /* 10-byte uses 4 bytes of LBA: 2147483648KB, 2097152MB, 2048GB */
734         cmd->cdb[2] = block >> 24;
735         cmd->cdb[3] = block >> 16;
736         cmd->cdb[4] = block >> 8;
737         cmd->cdb[5] = block;
738         cmd->cdb[7] = nblks >> 8;
739         cmd->cdb[8] = nblks;
740         cmd->cdb_len = 10;
741
742         cmd->len = rq->nr_sectors * 512;
743 }
744
745 static void ub_cmd_build_packet(struct ub_dev *sc, struct ub_lun *lun,
746     struct ub_scsi_cmd *cmd, struct ub_request *urq)
747 {
748         struct request *rq = urq->rq;
749
750         if (rq->data_len == 0) {
751                 cmd->dir = UB_DIR_NONE;
752         } else {
753                 if (rq_data_dir(rq) == WRITE)
754                         cmd->dir = UB_DIR_WRITE;
755                 else
756                         cmd->dir = UB_DIR_READ;
757         }
758
759         cmd->nsg = urq->nsg;
760         memcpy(cmd->sgv, urq->sgv, sizeof(struct scatterlist) * cmd->nsg);
761
762         memcpy(&cmd->cdb, rq->cmd, rq->cmd_len);
763         cmd->cdb_len = rq->cmd_len;
764
765         cmd->len = rq->data_len;
766
767         /*
768          * To reapply this to every URB is not as incorrect as it looks.
769          * In return, we avoid any complicated tracking calculations.
770          */
771         cmd->timeo = rq->timeout;
772 }
773
774 static void ub_rw_cmd_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
775 {
776         struct ub_lun *lun = cmd->lun;
777         struct ub_request *urq = cmd->back;
778         struct request *rq;
779         unsigned int scsi_status;
780         unsigned int cmd_len;
781
782         rq = urq->rq;
783
784         if (cmd->error == 0) {
785                 if (blk_pc_request(rq)) {
786                         if (cmd->act_len < rq->data_len)
787                                 rq->resid_len = rq->data_len - cmd->act_len;
788                         scsi_status = 0;
789                 } else {
790                         if (cmd->act_len != cmd->len) {
791                                 scsi_status = SAM_STAT_CHECK_CONDITION;
792                         } else {
793                                 scsi_status = 0;
794                         }
795                 }
796         } else {
797                 if (blk_pc_request(rq)) {
798                         /* UB_SENSE_SIZE is smaller than SCSI_SENSE_BUFFERSIZE */
799                         memcpy(rq->sense, sc->top_sense, UB_SENSE_SIZE);
800                         rq->sense_len = UB_SENSE_SIZE;
801                         if (sc->top_sense[0] != 0)
802                                 scsi_status = SAM_STAT_CHECK_CONDITION;
803                         else
804                                 scsi_status = DID_ERROR << 16;
805                 } else {
806                         if (cmd->error == -EIO &&
807                             (cmd->key == 0 ||
808                              cmd->key == MEDIUM_ERROR ||
809                              cmd->key == UNIT_ATTENTION)) {
810                                 if (ub_rw_cmd_retry(sc, lun, urq, cmd) == 0)
811                                         return;
812                         }
813                         scsi_status = SAM_STAT_CHECK_CONDITION;
814                 }
815         }
816
817         urq->rq = NULL;
818
819         cmd_len = cmd->len;
820         ub_put_cmd(lun, cmd);
821         ub_end_rq(rq, scsi_status, cmd_len);
822         blk_start_queue(lun->disk->queue);
823 }
824
825 static void ub_end_rq(struct request *rq, unsigned int scsi_status,
826     unsigned int cmd_len)
827 {
828         int error;
829         long rqlen;
830
831         if (scsi_status == 0) {
832                 error = 0;
833         } else {
834                 error = -EIO;
835                 rq->errors = scsi_status;
836         }
837         rqlen = blk_rq_bytes(rq);    /* Oddly enough, this is the residue. */
838         if (__blk_end_request(rq, error, cmd_len)) {
839                 printk(KERN_WARNING DRV_NAME
840                     ": __blk_end_request blew, %s-cmd total %u rqlen %ld\n",
841                     blk_pc_request(rq)? "pc": "fs", cmd_len, rqlen);
842         }
843 }
844
845 static int ub_rw_cmd_retry(struct ub_dev *sc, struct ub_lun *lun,
846     struct ub_request *urq, struct ub_scsi_cmd *cmd)
847 {
848
849         if (atomic_read(&sc->poison))
850                 return -ENXIO;
851
852         ub_reset_enter(sc, urq->current_try);
853
854         if (urq->current_try >= 3)
855                 return -EIO;
856         urq->current_try++;
857
858         /* Remove this if anyone complains of flooding. */
859         printk(KERN_DEBUG "%s: dir %c len/act %d/%d "
860             "[sense %x %02x %02x] retry %d\n",
861             sc->name, UB_DIR_CHAR(cmd->dir), cmd->len, cmd->act_len,
862             cmd->key, cmd->asc, cmd->ascq, urq->current_try);
863
864         memset(cmd, 0, sizeof(struct ub_scsi_cmd));
865         ub_cmd_build_block(sc, lun, cmd, urq);
866
867         cmd->state = UB_CMDST_INIT;
868         cmd->lun = lun;
869         cmd->done = ub_rw_cmd_done;
870         cmd->back = urq;
871
872         cmd->tag = sc->tagcnt++;
873
874 #if 0 /* Wasteful */
875         return ub_submit_scsi(sc, cmd);
876 #else
877         ub_cmdq_add(sc, cmd);
878         return 0;
879 #endif
880 }
881
882 /*
883  * Submit a regular SCSI operation (not an auto-sense).
884  *
885  * The Iron Law of Good Submit Routine is:
886  * Zero return - callback is done, Nonzero return - callback is not done.
887  * No exceptions.
888  *
889  * Host is assumed locked.
890  */
891 static int ub_submit_scsi(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
892 {
893
894         if (cmd->state != UB_CMDST_INIT ||
895             (cmd->dir != UB_DIR_NONE && cmd->len == 0)) {
896                 return -EINVAL;
897         }
898
899         ub_cmdq_add(sc, cmd);
900         /*
901          * We can call ub_scsi_dispatch(sc) right away here, but it's a little
902          * safer to jump to a tasklet, in case upper layers do something silly.
903          */
904         tasklet_schedule(&sc->tasklet);
905         return 0;
906 }
907
908 /*
909  * Submit the first URB for the queued command.
910  * This function does not deal with queueing in any way.
911  */
912 static int ub_scsi_cmd_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
913 {
914         struct bulk_cb_wrap *bcb;
915         int rc;
916
917         bcb = &sc->work_bcb;
918
919         /*
920          * ``If the allocation length is eighteen or greater, and a device
921          * server returns less than eithteen bytes of data, the application
922          * client should assume that the bytes not transferred would have been
923          * zeroes had the device server returned those bytes.''
924          *
925          * We zero sense for all commands so that when a packet request
926          * fails it does not return a stale sense.
927          */
928         memset(&sc->top_sense, 0, UB_SENSE_SIZE);
929
930         /* set up the command wrapper */
931         bcb->Signature = cpu_to_le32(US_BULK_CB_SIGN);
932         bcb->Tag = cmd->tag;            /* Endianness is not important */
933         bcb->DataTransferLength = cpu_to_le32(cmd->len);
934         bcb->Flags = (cmd->dir == UB_DIR_READ) ? 0x80 : 0;
935         bcb->Lun = (cmd->lun != NULL) ? cmd->lun->num : 0;
936         bcb->Length = cmd->cdb_len;
937
938         /* copy the command payload */
939         memcpy(bcb->CDB, cmd->cdb, UB_MAX_CDB_SIZE);
940
941         UB_INIT_COMPLETION(sc->work_done);
942
943         sc->last_pipe = sc->send_bulk_pipe;
944         usb_fill_bulk_urb(&sc->work_urb, sc->dev, sc->send_bulk_pipe,
945             bcb, US_BULK_CB_WRAP_LEN, ub_urb_complete, sc);
946
947         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
948                 /* XXX Clear stalls */
949                 ub_complete(&sc->work_done);
950                 return rc;
951         }
952
953         sc->work_timer.expires = jiffies + UB_URB_TIMEOUT;
954         add_timer(&sc->work_timer);
955
956         cmd->state = UB_CMDST_CMD;
957         return 0;
958 }
959
960 /*
961  * Timeout handler.
962  */
963 static void ub_urb_timeout(unsigned long arg)
964 {
965         struct ub_dev *sc = (struct ub_dev *) arg;
966         unsigned long flags;
967
968         spin_lock_irqsave(sc->lock, flags);
969         if (!ub_is_completed(&sc->work_done))
970                 usb_unlink_urb(&sc->work_urb);
971         spin_unlock_irqrestore(sc->lock, flags);
972 }
973
974 /*
975  * Completion routine for the work URB.
976  *
977  * This can be called directly from usb_submit_urb (while we have
978  * the sc->lock taken) and from an interrupt (while we do NOT have
979  * the sc->lock taken). Therefore, bounce this off to a tasklet.
980  */
981 static void ub_urb_complete(struct urb *urb)
982 {
983         struct ub_dev *sc = urb->context;
984
985         ub_complete(&sc->work_done);
986         tasklet_schedule(&sc->tasklet);
987 }
988
989 static void ub_scsi_action(unsigned long _dev)
990 {
991         struct ub_dev *sc = (struct ub_dev *) _dev;
992         unsigned long flags;
993
994         spin_lock_irqsave(sc->lock, flags);
995         ub_scsi_dispatch(sc);
996         spin_unlock_irqrestore(sc->lock, flags);
997 }
998
999 static void ub_scsi_dispatch(struct ub_dev *sc)
1000 {
1001         struct ub_scsi_cmd *cmd;
1002         int rc;
1003
1004         while (!sc->reset && (cmd = ub_cmdq_peek(sc)) != NULL) {
1005                 if (cmd->state == UB_CMDST_DONE) {
1006                         ub_cmdq_pop(sc);
1007                         (*cmd->done)(sc, cmd);
1008                 } else if (cmd->state == UB_CMDST_INIT) {
1009                         if ((rc = ub_scsi_cmd_start(sc, cmd)) == 0)
1010                                 break;
1011                         cmd->error = rc;
1012                         cmd->state = UB_CMDST_DONE;
1013                 } else {
1014                         if (!ub_is_completed(&sc->work_done))
1015                                 break;
1016                         del_timer(&sc->work_timer);
1017                         ub_scsi_urb_compl(sc, cmd);
1018                 }
1019         }
1020 }
1021
1022 static void ub_scsi_urb_compl(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1023 {
1024         struct urb *urb = &sc->work_urb;
1025         struct bulk_cs_wrap *bcs;
1026         int endp;
1027         int len;
1028         int rc;
1029
1030         if (atomic_read(&sc->poison)) {
1031                 ub_state_done(sc, cmd, -ENODEV);
1032                 return;
1033         }
1034
1035         endp = usb_pipeendpoint(sc->last_pipe);
1036         if (usb_pipein(sc->last_pipe))
1037                 endp |= USB_DIR_IN;
1038
1039         if (cmd->state == UB_CMDST_CLEAR) {
1040                 if (urb->status == -EPIPE) {
1041                         /*
1042                          * STALL while clearning STALL.
1043                          * The control pipe clears itself - nothing to do.
1044                          */
1045                         printk(KERN_NOTICE "%s: stall on control pipe\n",
1046                             sc->name);
1047                         goto Bad_End;
1048                 }
1049
1050                 /*
1051                  * We ignore the result for the halt clear.
1052                  */
1053
1054                 usb_reset_endpoint(sc->dev, endp);
1055
1056                 ub_state_sense(sc, cmd);
1057
1058         } else if (cmd->state == UB_CMDST_CLR2STS) {
1059                 if (urb->status == -EPIPE) {
1060                         printk(KERN_NOTICE "%s: stall on control pipe\n",
1061                             sc->name);
1062                         goto Bad_End;
1063                 }
1064
1065                 /*
1066                  * We ignore the result for the halt clear.
1067                  */
1068
1069                 usb_reset_endpoint(sc->dev, endp);
1070
1071                 ub_state_stat(sc, cmd);
1072
1073         } else if (cmd->state == UB_CMDST_CLRRS) {
1074                 if (urb->status == -EPIPE) {
1075                         printk(KERN_NOTICE "%s: stall on control pipe\n",
1076                             sc->name);
1077                         goto Bad_End;
1078                 }
1079
1080                 /*
1081                  * We ignore the result for the halt clear.
1082                  */
1083
1084                 usb_reset_endpoint(sc->dev, endp);
1085
1086                 ub_state_stat_counted(sc, cmd);
1087
1088         } else if (cmd->state == UB_CMDST_CMD) {
1089                 switch (urb->status) {
1090                 case 0:
1091                         break;
1092                 case -EOVERFLOW:
1093                         goto Bad_End;
1094                 case -EPIPE:
1095                         rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
1096                         if (rc != 0) {
1097                                 printk(KERN_NOTICE "%s: "
1098                                     "unable to submit clear (%d)\n",
1099                                     sc->name, rc);
1100                                 /*
1101                                  * This is typically ENOMEM or some other such shit.
1102                                  * Retrying is pointless. Just do Bad End on it...
1103                                  */
1104                                 ub_state_done(sc, cmd, rc);
1105                                 return;
1106                         }
1107                         cmd->state = UB_CMDST_CLEAR;
1108                         return;
1109                 case -ESHUTDOWN:        /* unplug */
1110                 case -EILSEQ:           /* unplug timeout on uhci */
1111                         ub_state_done(sc, cmd, -ENODEV);
1112                         return;
1113                 default:
1114                         goto Bad_End;
1115                 }
1116                 if (urb->actual_length != US_BULK_CB_WRAP_LEN) {
1117                         goto Bad_End;
1118                 }
1119
1120                 if (cmd->dir == UB_DIR_NONE || cmd->nsg < 1) {
1121                         ub_state_stat(sc, cmd);
1122                         return;
1123                 }
1124
1125                 // udelay(125);         // usb-storage has this
1126                 ub_data_start(sc, cmd);
1127
1128         } else if (cmd->state == UB_CMDST_DATA) {
1129                 if (urb->status == -EPIPE) {
1130                         rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
1131                         if (rc != 0) {
1132                                 printk(KERN_NOTICE "%s: "
1133                                     "unable to submit clear (%d)\n",
1134                                     sc->name, rc);
1135                                 ub_state_done(sc, cmd, rc);
1136                                 return;
1137                         }
1138                         cmd->state = UB_CMDST_CLR2STS;
1139                         return;
1140                 }
1141                 if (urb->status == -EOVERFLOW) {
1142                         /*
1143                          * A babble? Failure, but we must transfer CSW now.
1144                          */
1145                         cmd->error = -EOVERFLOW;        /* A cheap trick... */
1146                         ub_state_stat(sc, cmd);
1147                         return;
1148                 }
1149
1150                 if (cmd->dir == UB_DIR_WRITE) {
1151                         /*
1152                          * Do not continue writes in case of a failure.
1153                          * Doing so would cause sectors to be mixed up,
1154                          * which is worse than sectors lost.
1155                          *
1156                          * We must try to read the CSW, or many devices
1157                          * get confused.
1158                          */
1159                         len = urb->actual_length;
1160                         if (urb->status != 0 ||
1161                             len != cmd->sgv[cmd->current_sg].length) {
1162                                 cmd->act_len += len;
1163
1164                                 cmd->error = -EIO;
1165                                 ub_state_stat(sc, cmd);
1166                                 return;
1167                         }
1168
1169                 } else {
1170                         /*
1171                          * If an error occurs on read, we record it, and
1172                          * continue to fetch data in order to avoid bubble.
1173                          *
1174                          * As a small shortcut, we stop if we detect that
1175                          * a CSW mixed into data.
1176                          */
1177                         if (urb->status != 0)
1178                                 cmd->error = -EIO;
1179
1180                         len = urb->actual_length;
1181                         if (urb->status != 0 ||
1182                             len != cmd->sgv[cmd->current_sg].length) {
1183                                 if ((len & 0x1FF) == US_BULK_CS_WRAP_LEN)
1184                                         goto Bad_End;
1185                         }
1186                 }
1187
1188                 cmd->act_len += urb->actual_length;
1189
1190                 if (++cmd->current_sg < cmd->nsg) {
1191                         ub_data_start(sc, cmd);
1192                         return;
1193                 }
1194                 ub_state_stat(sc, cmd);
1195
1196         } else if (cmd->state == UB_CMDST_STAT) {
1197                 if (urb->status == -EPIPE) {
1198                         rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
1199                         if (rc != 0) {
1200                                 printk(KERN_NOTICE "%s: "
1201                                     "unable to submit clear (%d)\n",
1202                                     sc->name, rc);
1203                                 ub_state_done(sc, cmd, rc);
1204                                 return;
1205                         }
1206
1207                         /*
1208                          * Having a stall when getting CSW is an error, so
1209                          * make sure uppper levels are not oblivious to it.
1210                          */
1211                         cmd->error = -EIO;              /* A cheap trick... */
1212
1213                         cmd->state = UB_CMDST_CLRRS;
1214                         return;
1215                 }
1216
1217                 /* Catch everything, including -EOVERFLOW and other nasties. */
1218                 if (urb->status != 0)
1219                         goto Bad_End;
1220
1221                 if (urb->actual_length == 0) {
1222                         ub_state_stat_counted(sc, cmd);
1223                         return;
1224                 }
1225
1226                 /*
1227                  * Check the returned Bulk protocol status.
1228                  * The status block has to be validated first.
1229                  */
1230
1231                 bcs = &sc->work_bcs;
1232
1233                 if (sc->signature == cpu_to_le32(0)) {
1234                         /*
1235                          * This is the first reply, so do not perform the check.
1236                          * Instead, remember the signature the device uses
1237                          * for future checks. But do not allow a nul.
1238                          */
1239                         sc->signature = bcs->Signature;
1240                         if (sc->signature == cpu_to_le32(0)) {
1241                                 ub_state_stat_counted(sc, cmd);
1242                                 return;
1243                         }
1244                 } else {
1245                         if (bcs->Signature != sc->signature) {
1246                                 ub_state_stat_counted(sc, cmd);
1247                                 return;
1248                         }
1249                 }
1250
1251                 if (bcs->Tag != cmd->tag) {
1252                         /*
1253                          * This usually happens when we disagree with the
1254                          * device's microcode about something. For instance,
1255                          * a few of them throw this after timeouts. They buffer
1256                          * commands and reply at commands we timed out before.
1257                          * Without flushing these replies we loop forever.
1258                          */
1259                         ub_state_stat_counted(sc, cmd);
1260                         return;
1261                 }
1262
1263                 if (!sc->bad_resid) {
1264                         len = le32_to_cpu(bcs->Residue);
1265                         if (len != cmd->len - cmd->act_len) {
1266                                 /*
1267                                  * Only start ignoring if this cmd ended well.
1268                                  */
1269                                 if (cmd->len == cmd->act_len) {
1270                                         printk(KERN_NOTICE "%s: "
1271                                             "bad residual %d of %d, ignoring\n",
1272                                             sc->name, len, cmd->len);
1273                                         sc->bad_resid = 1;
1274                                 }
1275                         }
1276                 }
1277
1278                 switch (bcs->Status) {
1279                 case US_BULK_STAT_OK:
1280                         break;
1281                 case US_BULK_STAT_FAIL:
1282                         ub_state_sense(sc, cmd);
1283                         return;
1284                 case US_BULK_STAT_PHASE:
1285                         goto Bad_End;
1286                 default:
1287                         printk(KERN_INFO "%s: unknown CSW status 0x%x\n",
1288                             sc->name, bcs->Status);
1289                         ub_state_done(sc, cmd, -EINVAL);
1290                         return;
1291                 }
1292
1293                 /* Not zeroing error to preserve a babble indicator */
1294                 if (cmd->error != 0) {
1295                         ub_state_sense(sc, cmd);
1296                         return;
1297                 }
1298                 cmd->state = UB_CMDST_DONE;
1299                 ub_cmdq_pop(sc);
1300                 (*cmd->done)(sc, cmd);
1301
1302         } else if (cmd->state == UB_CMDST_SENSE) {
1303                 ub_state_done(sc, cmd, -EIO);
1304
1305         } else {
1306                 printk(KERN_WARNING "%s: wrong command state %d\n",
1307                     sc->name, cmd->state);
1308                 ub_state_done(sc, cmd, -EINVAL);
1309                 return;
1310         }
1311         return;
1312
1313 Bad_End: /* Little Excel is dead */
1314         ub_state_done(sc, cmd, -EIO);
1315 }
1316
1317 /*
1318  * Factorization helper for the command state machine:
1319  * Initiate a data segment transfer.
1320  */
1321 static void ub_data_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1322 {
1323         struct scatterlist *sg = &cmd->sgv[cmd->current_sg];
1324         int pipe;
1325         int rc;
1326
1327         UB_INIT_COMPLETION(sc->work_done);
1328
1329         if (cmd->dir == UB_DIR_READ)
1330                 pipe = sc->recv_bulk_pipe;
1331         else
1332                 pipe = sc->send_bulk_pipe;
1333         sc->last_pipe = pipe;
1334         usb_fill_bulk_urb(&sc->work_urb, sc->dev, pipe, sg_virt(sg),
1335             sg->length, ub_urb_complete, sc);
1336
1337         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
1338                 /* XXX Clear stalls */
1339                 ub_complete(&sc->work_done);
1340                 ub_state_done(sc, cmd, rc);
1341                 return;
1342         }
1343
1344         if (cmd->timeo)
1345                 sc->work_timer.expires = jiffies + cmd->timeo;
1346         else
1347                 sc->work_timer.expires = jiffies + UB_DATA_TIMEOUT;
1348         add_timer(&sc->work_timer);
1349
1350         cmd->state = UB_CMDST_DATA;
1351 }
1352
1353 /*
1354  * Factorization helper for the command state machine:
1355  * Finish the command.
1356  */
1357 static void ub_state_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd, int rc)
1358 {
1359
1360         cmd->error = rc;
1361         cmd->state = UB_CMDST_DONE;
1362         ub_cmdq_pop(sc);
1363         (*cmd->done)(sc, cmd);
1364 }
1365
1366 /*
1367  * Factorization helper for the command state machine:
1368  * Submit a CSW read.
1369  */
1370 static int __ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1371 {
1372         int rc;
1373
1374         UB_INIT_COMPLETION(sc->work_done);
1375
1376         sc->last_pipe = sc->recv_bulk_pipe;
1377         usb_fill_bulk_urb(&sc->work_urb, sc->dev, sc->recv_bulk_pipe,
1378             &sc->work_bcs, US_BULK_CS_WRAP_LEN, ub_urb_complete, sc);
1379
1380         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
1381                 /* XXX Clear stalls */
1382                 ub_complete(&sc->work_done);
1383                 ub_state_done(sc, cmd, rc);
1384                 return -1;
1385         }
1386
1387         if (cmd->timeo)
1388                 sc->work_timer.expires = jiffies + cmd->timeo;
1389         else
1390                 sc->work_timer.expires = jiffies + UB_STAT_TIMEOUT;
1391         add_timer(&sc->work_timer);
1392         return 0;
1393 }
1394
1395 /*
1396  * Factorization helper for the command state machine:
1397  * Submit a CSW read and go to STAT state.
1398  */
1399 static void ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1400 {
1401
1402         if (__ub_state_stat(sc, cmd) != 0)
1403                 return;
1404
1405         cmd->stat_count = 0;
1406         cmd->state = UB_CMDST_STAT;
1407 }
1408
1409 /*
1410  * Factorization helper for the command state machine:
1411  * Submit a CSW read and go to STAT state with counter (along [C] path).
1412  */
1413 static void ub_state_stat_counted(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1414 {
1415
1416         if (++cmd->stat_count >= 4) {
1417                 ub_state_sense(sc, cmd);
1418                 return;
1419         }
1420
1421         if (__ub_state_stat(sc, cmd) != 0)
1422                 return;
1423
1424         cmd->state = UB_CMDST_STAT;
1425 }
1426
1427 /*
1428  * Factorization helper for the command state machine:
1429  * Submit a REQUEST SENSE and go to SENSE state.
1430  */
1431 static void ub_state_sense(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1432 {
1433         struct ub_scsi_cmd *scmd;
1434         struct scatterlist *sg;
1435         int rc;
1436
1437         if (cmd->cdb[0] == REQUEST_SENSE) {
1438                 rc = -EPIPE;
1439                 goto error;
1440         }
1441
1442         scmd = &sc->top_rqs_cmd;
1443         memset(scmd, 0, sizeof(struct ub_scsi_cmd));
1444         scmd->cdb[0] = REQUEST_SENSE;
1445         scmd->cdb[4] = UB_SENSE_SIZE;
1446         scmd->cdb_len = 6;
1447         scmd->dir = UB_DIR_READ;
1448         scmd->state = UB_CMDST_INIT;
1449         scmd->nsg = 1;
1450         sg = &scmd->sgv[0];
1451         sg_init_table(sg, UB_MAX_REQ_SG);
1452         sg_set_page(sg, virt_to_page(sc->top_sense), UB_SENSE_SIZE,
1453                         (unsigned long)sc->top_sense & (PAGE_SIZE-1));
1454         scmd->len = UB_SENSE_SIZE;
1455         scmd->lun = cmd->lun;
1456         scmd->done = ub_top_sense_done;
1457         scmd->back = cmd;
1458
1459         scmd->tag = sc->tagcnt++;
1460
1461         cmd->state = UB_CMDST_SENSE;
1462
1463         ub_cmdq_insert(sc, scmd);
1464         return;
1465
1466 error:
1467         ub_state_done(sc, cmd, rc);
1468 }
1469
1470 /*
1471  * A helper for the command's state machine:
1472  * Submit a stall clear.
1473  */
1474 static int ub_submit_clear_stall(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
1475     int stalled_pipe)
1476 {
1477         int endp;
1478         struct usb_ctrlrequest *cr;
1479         int rc;
1480
1481         endp = usb_pipeendpoint(stalled_pipe);
1482         if (usb_pipein (stalled_pipe))
1483                 endp |= USB_DIR_IN;
1484
1485         cr = &sc->work_cr;
1486         cr->bRequestType = USB_RECIP_ENDPOINT;
1487         cr->bRequest = USB_REQ_CLEAR_FEATURE;
1488         cr->wValue = cpu_to_le16(USB_ENDPOINT_HALT);
1489         cr->wIndex = cpu_to_le16(endp);
1490         cr->wLength = cpu_to_le16(0);
1491
1492         UB_INIT_COMPLETION(sc->work_done);
1493
1494         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->send_ctrl_pipe,
1495             (unsigned char*) cr, NULL, 0, ub_urb_complete, sc);
1496
1497         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
1498                 ub_complete(&sc->work_done);
1499                 return rc;
1500         }
1501
1502         sc->work_timer.expires = jiffies + UB_CTRL_TIMEOUT;
1503         add_timer(&sc->work_timer);
1504         return 0;
1505 }
1506
1507 /*
1508  */
1509 static void ub_top_sense_done(struct ub_dev *sc, struct ub_scsi_cmd *scmd)
1510 {
1511         unsigned char *sense = sc->top_sense;
1512         struct ub_scsi_cmd *cmd;
1513
1514         /*
1515          * Find the command which triggered the unit attention or a check,
1516          * save the sense into it, and advance its state machine.
1517          */
1518         if ((cmd = ub_cmdq_peek(sc)) == NULL) {
1519                 printk(KERN_WARNING "%s: sense done while idle\n", sc->name);
1520                 return;
1521         }
1522         if (cmd != scmd->back) {
1523                 printk(KERN_WARNING "%s: "
1524                     "sense done for wrong command 0x%x\n",
1525                     sc->name, cmd->tag);
1526                 return;
1527         }
1528         if (cmd->state != UB_CMDST_SENSE) {
1529                 printk(KERN_WARNING "%s: sense done with bad cmd state %d\n",
1530                     sc->name, cmd->state);
1531                 return;
1532         }
1533
1534         /*
1535          * Ignoring scmd->act_len, because the buffer was pre-zeroed.
1536          */
1537         cmd->key = sense[2] & 0x0F;
1538         cmd->asc = sense[12];
1539         cmd->ascq = sense[13];
1540
1541         ub_scsi_urb_compl(sc, cmd);
1542 }
1543
1544 /*
1545  * Reset management
1546  */
1547
1548 static void ub_reset_enter(struct ub_dev *sc, int try)
1549 {
1550
1551         if (sc->reset) {
1552                 /* This happens often on multi-LUN devices. */
1553                 return;
1554         }
1555         sc->reset = try + 1;
1556
1557 #if 0 /* Not needed because the disconnect waits for us. */
1558         unsigned long flags;
1559         spin_lock_irqsave(&ub_lock, flags);
1560         sc->openc++;
1561         spin_unlock_irqrestore(&ub_lock, flags);
1562 #endif
1563
1564 #if 0 /* We let them stop themselves. */
1565         struct ub_lun *lun;
1566         list_for_each_entry(lun, &sc->luns, link) {
1567                 blk_stop_queue(lun->disk->queue);
1568         }
1569 #endif
1570
1571         schedule_work(&sc->reset_work);
1572 }
1573
1574 static void ub_reset_task(struct work_struct *work)
1575 {
1576         struct ub_dev *sc = container_of(work, struct ub_dev, reset_work);
1577         unsigned long flags;
1578         struct ub_lun *lun;
1579         int rc;
1580
1581         if (!sc->reset) {
1582                 printk(KERN_WARNING "%s: Running reset unrequested\n",
1583                     sc->name);
1584                 return;
1585         }
1586
1587         if (atomic_read(&sc->poison)) {
1588                 ;
1589         } else if ((sc->reset & 1) == 0) {
1590                 ub_sync_reset(sc);
1591                 msleep(700);    /* usb-storage sleeps 6s (!) */
1592                 ub_probe_clear_stall(sc, sc->recv_bulk_pipe);
1593                 ub_probe_clear_stall(sc, sc->send_bulk_pipe);
1594         } else if (sc->dev->actconfig->desc.bNumInterfaces != 1) {
1595                 ;
1596         } else {
1597                 rc = usb_lock_device_for_reset(sc->dev, sc->intf);
1598                 if (rc < 0) {
1599                         printk(KERN_NOTICE
1600                             "%s: usb_lock_device_for_reset failed (%d)\n",
1601                             sc->name, rc);
1602                 } else {
1603                         rc = usb_reset_device(sc->dev);
1604                         if (rc < 0) {
1605                                 printk(KERN_NOTICE "%s: "
1606                                     "usb_lock_device_for_reset failed (%d)\n",
1607                                     sc->name, rc);
1608                         }
1609                         usb_unlock_device(sc->dev);
1610                 }
1611         }
1612
1613         /*
1614          * In theory, no commands can be running while reset is active,
1615          * so nobody can ask for another reset, and so we do not need any
1616          * queues of resets or anything. We do need a spinlock though,
1617          * to interact with block layer.
1618          */
1619         spin_lock_irqsave(sc->lock, flags);
1620         sc->reset = 0;
1621         tasklet_schedule(&sc->tasklet);
1622         list_for_each_entry(lun, &sc->luns, link) {
1623                 blk_start_queue(lun->disk->queue);
1624         }
1625         wake_up(&sc->reset_wait);
1626         spin_unlock_irqrestore(sc->lock, flags);
1627 }
1628
1629 /*
1630  * XXX Reset brackets are too much hassle to implement, so just stub them
1631  * in order to prevent forced unbinding (which deadlocks solid when our
1632  * ->disconnect method waits for the reset to complete and this kills keventd).
1633  *
1634  * XXX Tell Alan to move usb_unlock_device inside of usb_reset_device,
1635  * or else the post_reset is invoked, and restats I/O on a locked device.
1636  */
1637 static int ub_pre_reset(struct usb_interface *iface) {
1638         return 0;
1639 }
1640
1641 static int ub_post_reset(struct usb_interface *iface) {
1642         return 0;
1643 }
1644
1645 /*
1646  * This is called from a process context.
1647  */
1648 static void ub_revalidate(struct ub_dev *sc, struct ub_lun *lun)
1649 {
1650
1651         lun->readonly = 0;      /* XXX Query this from the device */
1652
1653         lun->capacity.nsec = 0;
1654         lun->capacity.bsize = 512;
1655         lun->capacity.bshift = 0;
1656
1657         if (ub_sync_tur(sc, lun) != 0)
1658                 return;                 /* Not ready */
1659         lun->changed = 0;
1660
1661         if (ub_sync_read_cap(sc, lun, &lun->capacity) != 0) {
1662                 /*
1663                  * The retry here means something is wrong, either with the
1664                  * device, with the transport, or with our code.
1665                  * We keep this because sd.c has retries for capacity.
1666                  */
1667                 if (ub_sync_read_cap(sc, lun, &lun->capacity) != 0) {
1668                         lun->capacity.nsec = 0;
1669                         lun->capacity.bsize = 512;
1670                         lun->capacity.bshift = 0;
1671                 }
1672         }
1673 }
1674
1675 /*
1676  * The open funcion.
1677  * This is mostly needed to keep refcounting, but also to support
1678  * media checks on removable media drives.
1679  */
1680 static int ub_bd_open(struct block_device *bdev, fmode_t mode)
1681 {
1682         struct ub_lun *lun = bdev->bd_disk->private_data;
1683         struct ub_dev *sc = lun->udev;
1684         unsigned long flags;
1685         int rc;
1686
1687         spin_lock_irqsave(&ub_lock, flags);
1688         if (atomic_read(&sc->poison)) {
1689                 spin_unlock_irqrestore(&ub_lock, flags);
1690                 return -ENXIO;
1691         }
1692         sc->openc++;
1693         spin_unlock_irqrestore(&ub_lock, flags);
1694
1695         if (lun->removable || lun->readonly)
1696                 check_disk_change(bdev);
1697
1698         /*
1699          * The sd.c considers ->media_present and ->changed not equivalent,
1700          * under some pretty murky conditions (a failure of READ CAPACITY).
1701          * We may need it one day.
1702          */
1703         if (lun->removable && lun->changed && !(mode & FMODE_NDELAY)) {
1704                 rc = -ENOMEDIUM;
1705                 goto err_open;
1706         }
1707
1708         if (lun->readonly && (mode & FMODE_WRITE)) {
1709                 rc = -EROFS;
1710                 goto err_open;
1711         }
1712
1713         return 0;
1714
1715 err_open:
1716         ub_put(sc);
1717         return rc;
1718 }
1719
1720 /*
1721  */
1722 static int ub_bd_release(struct gendisk *disk, fmode_t mode)
1723 {
1724         struct ub_lun *lun = disk->private_data;
1725         struct ub_dev *sc = lun->udev;
1726
1727         ub_put(sc);
1728         return 0;
1729 }
1730
1731 /*
1732  * The ioctl interface.
1733  */
1734 static int ub_bd_ioctl(struct block_device *bdev, fmode_t mode,
1735     unsigned int cmd, unsigned long arg)
1736 {
1737         struct gendisk *disk = bdev->bd_disk;
1738         void __user *usermem = (void __user *) arg;
1739
1740         return scsi_cmd_ioctl(disk->queue, disk, mode, cmd, usermem);
1741 }
1742
1743 /*
1744  * This is called by check_disk_change if we reported a media change.
1745  * The main onjective here is to discover the features of the media such as
1746  * the capacity, read-only status, etc. USB storage generally does not
1747  * need to be spun up, but if we needed it, this would be the place.
1748  *
1749  * This call can sleep.
1750  *
1751  * The return code is not used.
1752  */
1753 static int ub_bd_revalidate(struct gendisk *disk)
1754 {
1755         struct ub_lun *lun = disk->private_data;
1756
1757         ub_revalidate(lun->udev, lun);
1758
1759         /* XXX Support sector size switching like in sr.c */
1760         blk_queue_hardsect_size(disk->queue, lun->capacity.bsize);
1761         set_capacity(disk, lun->capacity.nsec);
1762         // set_disk_ro(sdkp->disk, lun->readonly);
1763
1764         return 0;
1765 }
1766
1767 /*
1768  * The check is called by the block layer to verify if the media
1769  * is still available. It is supposed to be harmless, lightweight and
1770  * non-intrusive in case the media was not changed.
1771  *
1772  * This call can sleep.
1773  *
1774  * The return code is bool!
1775  */
1776 static int ub_bd_media_changed(struct gendisk *disk)
1777 {
1778         struct ub_lun *lun = disk->private_data;
1779
1780         if (!lun->removable)
1781                 return 0;
1782
1783         /*
1784          * We clean checks always after every command, so this is not
1785          * as dangerous as it looks. If the TEST_UNIT_READY fails here,
1786          * the device is actually not ready with operator or software
1787          * intervention required. One dangerous item might be a drive which
1788          * spins itself down, and come the time to write dirty pages, this
1789          * will fail, then block layer discards the data. Since we never
1790          * spin drives up, such devices simply cannot be used with ub anyway.
1791          */
1792         if (ub_sync_tur(lun->udev, lun) != 0) {
1793                 lun->changed = 1;
1794                 return 1;
1795         }
1796
1797         return lun->changed;
1798 }
1799
1800 static struct block_device_operations ub_bd_fops = {
1801         .owner          = THIS_MODULE,
1802         .open           = ub_bd_open,
1803         .release        = ub_bd_release,
1804         .locked_ioctl   = ub_bd_ioctl,
1805         .media_changed  = ub_bd_media_changed,
1806         .revalidate_disk = ub_bd_revalidate,
1807 };
1808
1809 /*
1810  * Common ->done routine for commands executed synchronously.
1811  */
1812 static void ub_probe_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1813 {
1814         struct completion *cop = cmd->back;
1815         complete(cop);
1816 }
1817
1818 /*
1819  * Test if the device has a check condition on it, synchronously.
1820  */
1821 static int ub_sync_tur(struct ub_dev *sc, struct ub_lun *lun)
1822 {
1823         struct ub_scsi_cmd *cmd;
1824         enum { ALLOC_SIZE = sizeof(struct ub_scsi_cmd) };
1825         unsigned long flags;
1826         struct completion compl;
1827         int rc;
1828
1829         init_completion(&compl);
1830
1831         rc = -ENOMEM;
1832         if ((cmd = kzalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
1833                 goto err_alloc;
1834
1835         cmd->cdb[0] = TEST_UNIT_READY;
1836         cmd->cdb_len = 6;
1837         cmd->dir = UB_DIR_NONE;
1838         cmd->state = UB_CMDST_INIT;
1839         cmd->lun = lun;                 /* This may be NULL, but that's ok */
1840         cmd->done = ub_probe_done;
1841         cmd->back = &compl;
1842
1843         spin_lock_irqsave(sc->lock, flags);
1844         cmd->tag = sc->tagcnt++;
1845
1846         rc = ub_submit_scsi(sc, cmd);
1847         spin_unlock_irqrestore(sc->lock, flags);
1848
1849         if (rc != 0)
1850                 goto err_submit;
1851
1852         wait_for_completion(&compl);
1853
1854         rc = cmd->error;
1855
1856         if (rc == -EIO && cmd->key != 0)        /* Retries for benh's key */
1857                 rc = cmd->key;
1858
1859 err_submit:
1860         kfree(cmd);
1861 err_alloc:
1862         return rc;
1863 }
1864
1865 /*
1866  * Read the SCSI capacity synchronously (for probing).
1867  */
1868 static int ub_sync_read_cap(struct ub_dev *sc, struct ub_lun *lun,
1869     struct ub_capacity *ret)
1870 {
1871         struct ub_scsi_cmd *cmd;
1872         struct scatterlist *sg;
1873         char *p;
1874         enum { ALLOC_SIZE = sizeof(struct ub_scsi_cmd) + 8 };
1875         unsigned long flags;
1876         unsigned int bsize, shift;
1877         unsigned long nsec;
1878         struct completion compl;
1879         int rc;
1880
1881         init_completion(&compl);
1882
1883         rc = -ENOMEM;
1884         if ((cmd = kzalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
1885                 goto err_alloc;
1886         p = (char *)cmd + sizeof(struct ub_scsi_cmd);
1887
1888         cmd->cdb[0] = 0x25;
1889         cmd->cdb_len = 10;
1890         cmd->dir = UB_DIR_READ;
1891         cmd->state = UB_CMDST_INIT;
1892         cmd->nsg = 1;
1893         sg = &cmd->sgv[0];
1894         sg_init_table(sg, UB_MAX_REQ_SG);
1895         sg_set_page(sg, virt_to_page(p), 8, (unsigned long)p & (PAGE_SIZE-1));
1896         cmd->len = 8;
1897         cmd->lun = lun;
1898         cmd->done = ub_probe_done;
1899         cmd->back = &compl;
1900
1901         spin_lock_irqsave(sc->lock, flags);
1902         cmd->tag = sc->tagcnt++;
1903
1904         rc = ub_submit_scsi(sc, cmd);
1905         spin_unlock_irqrestore(sc->lock, flags);
1906
1907         if (rc != 0)
1908                 goto err_submit;
1909
1910         wait_for_completion(&compl);
1911
1912         if (cmd->error != 0) {
1913                 rc = -EIO;
1914                 goto err_read;
1915         }
1916         if (cmd->act_len != 8) {
1917                 rc = -EIO;
1918                 goto err_read;
1919         }
1920
1921         /* sd.c special-cases sector size of 0 to mean 512. Needed? Safe? */
1922         nsec = be32_to_cpu(*(__be32 *)p) + 1;
1923         bsize = be32_to_cpu(*(__be32 *)(p + 4));
1924         switch (bsize) {
1925         case 512:       shift = 0;      break;
1926         case 1024:      shift = 1;      break;
1927         case 2048:      shift = 2;      break;
1928         case 4096:      shift = 3;      break;
1929         default:
1930                 rc = -EDOM;
1931                 goto err_inv_bsize;
1932         }
1933
1934         ret->bsize = bsize;
1935         ret->bshift = shift;
1936         ret->nsec = nsec << shift;
1937         rc = 0;
1938
1939 err_inv_bsize:
1940 err_read:
1941 err_submit:
1942         kfree(cmd);
1943 err_alloc:
1944         return rc;
1945 }
1946
1947 /*
1948  */
1949 static void ub_probe_urb_complete(struct urb *urb)
1950 {
1951         struct completion *cop = urb->context;
1952         complete(cop);
1953 }
1954
1955 static void ub_probe_timeout(unsigned long arg)
1956 {
1957         struct completion *cop = (struct completion *) arg;
1958         complete(cop);
1959 }
1960
1961 /*
1962  * Reset with a Bulk reset.
1963  */
1964 static int ub_sync_reset(struct ub_dev *sc)
1965 {
1966         int ifnum = sc->intf->cur_altsetting->desc.bInterfaceNumber;
1967         struct usb_ctrlrequest *cr;
1968         struct completion compl;
1969         struct timer_list timer;
1970         int rc;
1971
1972         init_completion(&compl);
1973
1974         cr = &sc->work_cr;
1975         cr->bRequestType = USB_TYPE_CLASS | USB_RECIP_INTERFACE;
1976         cr->bRequest = US_BULK_RESET_REQUEST;
1977         cr->wValue = cpu_to_le16(0);
1978         cr->wIndex = cpu_to_le16(ifnum);
1979         cr->wLength = cpu_to_le16(0);
1980
1981         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->send_ctrl_pipe,
1982             (unsigned char*) cr, NULL, 0, ub_probe_urb_complete, &compl);
1983
1984         if ((rc = usb_submit_urb(&sc->work_urb, GFP_KERNEL)) != 0) {
1985                 printk(KERN_WARNING
1986                      "%s: Unable to submit a bulk reset (%d)\n", sc->name, rc);
1987                 return rc;
1988         }
1989
1990         init_timer(&timer);
1991         timer.function = ub_probe_timeout;
1992         timer.data = (unsigned long) &compl;
1993         timer.expires = jiffies + UB_CTRL_TIMEOUT;
1994         add_timer(&timer);
1995
1996         wait_for_completion(&compl);
1997
1998         del_timer_sync(&timer);
1999         usb_kill_urb(&sc->work_urb);
2000
2001         return sc->work_urb.status;
2002 }
2003
2004 /*
2005  * Get number of LUNs by the way of Bulk GetMaxLUN command.
2006  */
2007 static int ub_sync_getmaxlun(struct ub_dev *sc)
2008 {
2009         int ifnum = sc->intf->cur_altsetting->desc.bInterfaceNumber;
2010         unsigned char *p;
2011         enum { ALLOC_SIZE = 1 };
2012         struct usb_ctrlrequest *cr;
2013         struct completion compl;
2014         struct timer_list timer;
2015         int nluns;
2016         int rc;
2017
2018         init_completion(&compl);
2019
2020         rc = -ENOMEM;
2021         if ((p = kmalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
2022                 goto err_alloc;
2023         *p = 55;
2024
2025         cr = &sc->work_cr;
2026         cr->bRequestType = USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE;
2027         cr->bRequest = US_BULK_GET_MAX_LUN;
2028         cr->wValue = cpu_to_le16(0);
2029         cr->wIndex = cpu_to_le16(ifnum);
2030         cr->wLength = cpu_to_le16(1);
2031
2032         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->recv_ctrl_pipe,
2033             (unsigned char*) cr, p, 1, ub_probe_urb_complete, &compl);
2034
2035         if ((rc = usb_submit_urb(&sc->work_urb, GFP_KERNEL)) != 0)
2036                 goto err_submit;
2037
2038         init_timer(&timer);
2039         timer.function = ub_probe_timeout;
2040         timer.data = (unsigned long) &compl;
2041         timer.expires = jiffies + UB_CTRL_TIMEOUT;
2042         add_timer(&timer);
2043
2044         wait_for_completion(&compl);
2045
2046         del_timer_sync(&timer);
2047         usb_kill_urb(&sc->work_urb);
2048
2049         if ((rc = sc->work_urb.status) < 0)
2050                 goto err_io;
2051
2052         if (sc->work_urb.actual_length != 1) {
2053                 nluns = 0;
2054         } else {
2055                 if ((nluns = *p) == 55) {
2056                         nluns = 0;
2057                 } else {
2058                         /* GetMaxLUN returns the maximum LUN number */
2059                         nluns += 1;
2060                         if (nluns > UB_MAX_LUNS)
2061                                 nluns = UB_MAX_LUNS;
2062                 }
2063         }
2064
2065         kfree(p);
2066         return nluns;
2067
2068 err_io:
2069 err_submit:
2070         kfree(p);
2071 err_alloc:
2072         return rc;
2073 }
2074
2075 /*
2076  * Clear initial stalls.
2077  */
2078 static int ub_probe_clear_stall(struct ub_dev *sc, int stalled_pipe)
2079 {
2080         int endp;
2081         struct usb_ctrlrequest *cr;
2082         struct completion compl;
2083         struct timer_list timer;
2084         int rc;
2085
2086         init_completion(&compl);
2087
2088         endp = usb_pipeendpoint(stalled_pipe);
2089         if (usb_pipein (stalled_pipe))
2090                 endp |= USB_DIR_IN;
2091
2092         cr = &sc->work_cr;
2093         cr->bRequestType = USB_RECIP_ENDPOINT;
2094         cr->bRequest = USB_REQ_CLEAR_FEATURE;
2095         cr->wValue = cpu_to_le16(USB_ENDPOINT_HALT);
2096         cr->wIndex = cpu_to_le16(endp);
2097         cr->wLength = cpu_to_le16(0);
2098
2099         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->send_ctrl_pipe,
2100             (unsigned char*) cr, NULL, 0, ub_probe_urb_complete, &compl);
2101
2102         if ((rc = usb_submit_urb(&sc->work_urb, GFP_KERNEL)) != 0) {
2103                 printk(KERN_WARNING
2104                      "%s: Unable to submit a probe clear (%d)\n", sc->name, rc);
2105                 return rc;
2106         }
2107
2108         init_timer(&timer);
2109         timer.function = ub_probe_timeout;
2110         timer.data = (unsigned long) &compl;
2111         timer.expires = jiffies + UB_CTRL_TIMEOUT;
2112         add_timer(&timer);
2113
2114         wait_for_completion(&compl);
2115
2116         del_timer_sync(&timer);
2117         usb_kill_urb(&sc->work_urb);
2118
2119         usb_reset_endpoint(sc->dev, endp);
2120
2121         return 0;
2122 }
2123
2124 /*
2125  * Get the pipe settings.
2126  */
2127 static int ub_get_pipes(struct ub_dev *sc, struct usb_device *dev,
2128     struct usb_interface *intf)
2129 {
2130         struct usb_host_interface *altsetting = intf->cur_altsetting;
2131         struct usb_endpoint_descriptor *ep_in = NULL;
2132         struct usb_endpoint_descriptor *ep_out = NULL;
2133         struct usb_endpoint_descriptor *ep;
2134         int i;
2135
2136         /*
2137          * Find the endpoints we need.
2138          * We are expecting a minimum of 2 endpoints - in and out (bulk).
2139          * We will ignore any others.
2140          */
2141         for (i = 0; i < altsetting->desc.bNumEndpoints; i++) {
2142                 ep = &altsetting->endpoint[i].desc;
2143
2144                 /* Is it a BULK endpoint? */
2145                 if (usb_endpoint_xfer_bulk(ep)) {
2146                         /* BULK in or out? */
2147                         if (usb_endpoint_dir_in(ep)) {
2148                                 if (ep_in == NULL)
2149                                         ep_in = ep;
2150                         } else {
2151                                 if (ep_out == NULL)
2152                                         ep_out = ep;
2153                         }
2154                 }
2155         }
2156
2157         if (ep_in == NULL || ep_out == NULL) {
2158                 printk(KERN_NOTICE "%s: failed endpoint check\n", sc->name);
2159                 return -ENODEV;
2160         }
2161
2162         /* Calculate and store the pipe values */
2163         sc->send_ctrl_pipe = usb_sndctrlpipe(dev, 0);
2164         sc->recv_ctrl_pipe = usb_rcvctrlpipe(dev, 0);
2165         sc->send_bulk_pipe = usb_sndbulkpipe(dev,
2166                 usb_endpoint_num(ep_out));
2167         sc->recv_bulk_pipe = usb_rcvbulkpipe(dev, 
2168                 usb_endpoint_num(ep_in));
2169
2170         return 0;
2171 }
2172
2173 /*
2174  * Probing is done in the process context, which allows us to cheat
2175  * and not to build a state machine for the discovery.
2176  */
2177 static int ub_probe(struct usb_interface *intf,
2178     const struct usb_device_id *dev_id)
2179 {
2180         struct ub_dev *sc;
2181         int nluns;
2182         int rc;
2183         int i;
2184
2185         if (usb_usual_check_type(dev_id, USB_US_TYPE_UB))
2186                 return -ENXIO;
2187
2188         rc = -ENOMEM;
2189         if ((sc = kzalloc(sizeof(struct ub_dev), GFP_KERNEL)) == NULL)
2190                 goto err_core;
2191         sc->lock = ub_next_lock();
2192         INIT_LIST_HEAD(&sc->luns);
2193         usb_init_urb(&sc->work_urb);
2194         tasklet_init(&sc->tasklet, ub_scsi_action, (unsigned long)sc);
2195         atomic_set(&sc->poison, 0);
2196         INIT_WORK(&sc->reset_work, ub_reset_task);
2197         init_waitqueue_head(&sc->reset_wait);
2198
2199         init_timer(&sc->work_timer);
2200         sc->work_timer.data = (unsigned long) sc;
2201         sc->work_timer.function = ub_urb_timeout;
2202
2203         ub_init_completion(&sc->work_done);
2204         sc->work_done.done = 1;         /* A little yuk, but oh well... */
2205
2206         sc->dev = interface_to_usbdev(intf);
2207         sc->intf = intf;
2208         // sc->ifnum = intf->cur_altsetting->desc.bInterfaceNumber;
2209         usb_set_intfdata(intf, sc);
2210         usb_get_dev(sc->dev);
2211         /*
2212          * Since we give the interface struct to the block level through
2213          * disk->driverfs_dev, we have to pin it. Otherwise, block_uevent
2214          * oopses on close after a disconnect (kernels 2.6.16 and up).
2215          */
2216         usb_get_intf(sc->intf);
2217
2218         snprintf(sc->name, 12, DRV_NAME "(%d.%d)",
2219             sc->dev->bus->busnum, sc->dev->devnum);
2220
2221         /* XXX Verify that we can handle the device (from descriptors) */
2222
2223         if (ub_get_pipes(sc, sc->dev, intf) != 0)
2224                 goto err_dev_desc;
2225
2226         /*
2227          * At this point, all USB initialization is done, do upper layer.
2228          * We really hate halfway initialized structures, so from the
2229          * invariants perspective, this ub_dev is fully constructed at
2230          * this point.
2231          */
2232
2233         /*
2234          * This is needed to clear toggles. It is a problem only if we do
2235          * `rmmod ub && modprobe ub` without disconnects, but we like that.
2236          */
2237 #if 0 /* iPod Mini fails if we do this (big white iPod works) */
2238         ub_probe_clear_stall(sc, sc->recv_bulk_pipe);
2239         ub_probe_clear_stall(sc, sc->send_bulk_pipe);
2240 #endif
2241
2242         /*
2243          * The way this is used by the startup code is a little specific.
2244          * A SCSI check causes a USB stall. Our common case code sees it
2245          * and clears the check, after which the device is ready for use.
2246          * But if a check was not present, any command other than
2247          * TEST_UNIT_READY ends with a lockup (including REQUEST_SENSE).
2248          *
2249          * If we neglect to clear the SCSI check, the first real command fails
2250          * (which is the capacity readout). We clear that and retry, but why
2251          * causing spurious retries for no reason.
2252          *
2253          * Revalidation may start with its own TEST_UNIT_READY, but that one
2254          * has to succeed, so we clear checks with an additional one here.
2255          * In any case it's not our business how revaliadation is implemented.
2256          */
2257         for (i = 0; i < 3; i++) {  /* Retries for the schwag key from KS'04 */
2258                 if ((rc = ub_sync_tur(sc, NULL)) <= 0) break;
2259                 if (rc != 0x6) break;
2260                 msleep(10);
2261         }
2262
2263         nluns = 1;
2264         for (i = 0; i < 3; i++) {
2265                 if ((rc = ub_sync_getmaxlun(sc)) < 0)
2266                         break;
2267                 if (rc != 0) {
2268                         nluns = rc;
2269                         break;
2270                 }
2271                 msleep(100);
2272         }
2273
2274         for (i = 0; i < nluns; i++) {
2275                 ub_probe_lun(sc, i);
2276         }
2277         return 0;
2278
2279 err_dev_desc:
2280         usb_set_intfdata(intf, NULL);
2281         usb_put_intf(sc->intf);
2282         usb_put_dev(sc->dev);
2283         kfree(sc);
2284 err_core:
2285         return rc;
2286 }
2287
2288 static int ub_probe_lun(struct ub_dev *sc, int lnum)
2289 {
2290         struct ub_lun *lun;
2291         struct request_queue *q;
2292         struct gendisk *disk;
2293         int rc;
2294
2295         rc = -ENOMEM;
2296         if ((lun = kzalloc(sizeof(struct ub_lun), GFP_KERNEL)) == NULL)
2297                 goto err_alloc;
2298         lun->num = lnum;
2299
2300         rc = -ENOSR;
2301         if ((lun->id = ub_id_get()) == -1)
2302                 goto err_id;
2303
2304         lun->udev = sc;
2305
2306         snprintf(lun->name, 16, DRV_NAME "%c(%d.%d.%d)",
2307             lun->id + 'a', sc->dev->bus->busnum, sc->dev->devnum, lun->num);
2308
2309         lun->removable = 1;             /* XXX Query this from the device */
2310         lun->changed = 1;               /* ub_revalidate clears only */
2311         ub_revalidate(sc, lun);
2312
2313         rc = -ENOMEM;
2314         if ((disk = alloc_disk(UB_PARTS_PER_LUN)) == NULL)
2315                 goto err_diskalloc;
2316
2317         sprintf(disk->disk_name, DRV_NAME "%c", lun->id + 'a');
2318         disk->major = UB_MAJOR;
2319         disk->first_minor = lun->id * UB_PARTS_PER_LUN;
2320         disk->fops = &ub_bd_fops;
2321         disk->private_data = lun;
2322         disk->driverfs_dev = &sc->intf->dev;
2323
2324         rc = -ENOMEM;
2325         if ((q = blk_init_queue(ub_request_fn, sc->lock)) == NULL)
2326                 goto err_blkqinit;
2327
2328         disk->queue = q;
2329
2330         blk_queue_bounce_limit(q, BLK_BOUNCE_HIGH);
2331         blk_queue_max_hw_segments(q, UB_MAX_REQ_SG);
2332         blk_queue_max_phys_segments(q, UB_MAX_REQ_SG);
2333         blk_queue_segment_boundary(q, 0xffffffff);      /* Dubious. */
2334         blk_queue_max_sectors(q, UB_MAX_SECTORS);
2335         blk_queue_hardsect_size(q, lun->capacity.bsize);
2336
2337         lun->disk = disk;
2338         q->queuedata = lun;
2339         list_add(&lun->link, &sc->luns);
2340
2341         set_capacity(disk, lun->capacity.nsec);
2342         if (lun->removable)
2343                 disk->flags |= GENHD_FL_REMOVABLE;
2344
2345         add_disk(disk);
2346
2347         return 0;
2348
2349 err_blkqinit:
2350         put_disk(disk);
2351 err_diskalloc:
2352         ub_id_put(lun->id);
2353 err_id:
2354         kfree(lun);
2355 err_alloc:
2356         return rc;
2357 }
2358
2359 static void ub_disconnect(struct usb_interface *intf)
2360 {
2361         struct ub_dev *sc = usb_get_intfdata(intf);
2362         struct ub_lun *lun;
2363         unsigned long flags;
2364
2365         /*
2366          * Prevent ub_bd_release from pulling the rug from under us.
2367          * XXX This is starting to look like a kref.
2368          * XXX Why not to take this ref at probe time?
2369          */
2370         spin_lock_irqsave(&ub_lock, flags);
2371         sc->openc++;
2372         spin_unlock_irqrestore(&ub_lock, flags);
2373
2374         /*
2375          * Fence stall clearings, operations triggered by unlinkings and so on.
2376          * We do not attempt to unlink any URBs, because we do not trust the
2377          * unlink paths in HC drivers. Also, we get -84 upon disconnect anyway.
2378          */
2379         atomic_set(&sc->poison, 1);
2380
2381         /*
2382          * Wait for reset to end, if any.
2383          */
2384         wait_event(sc->reset_wait, !sc->reset);
2385
2386         /*
2387          * Blow away queued commands.
2388          *
2389          * Actually, this never works, because before we get here
2390          * the HCD terminates outstanding URB(s). It causes our
2391          * SCSI command queue to advance, commands fail to submit,
2392          * and the whole queue drains. So, we just use this code to
2393          * print warnings.
2394          */
2395         spin_lock_irqsave(sc->lock, flags);
2396         {
2397                 struct ub_scsi_cmd *cmd;
2398                 int cnt = 0;
2399                 while ((cmd = ub_cmdq_peek(sc)) != NULL) {
2400                         cmd->error = -ENOTCONN;
2401                         cmd->state = UB_CMDST_DONE;
2402                         ub_cmdq_pop(sc);
2403                         (*cmd->done)(sc, cmd);
2404                         cnt++;
2405                 }
2406                 if (cnt != 0) {
2407                         printk(KERN_WARNING "%s: "
2408                             "%d was queued after shutdown\n", sc->name, cnt);
2409                 }
2410         }
2411         spin_unlock_irqrestore(sc->lock, flags);
2412
2413         /*
2414          * Unregister the upper layer.
2415          */
2416         list_for_each_entry(lun, &sc->luns, link) {
2417                 del_gendisk(lun->disk);
2418                 /*
2419                  * I wish I could do:
2420                  *    queue_flag_set(QUEUE_FLAG_DEAD, q);
2421                  * As it is, we rely on our internal poisoning and let
2422                  * the upper levels to spin furiously failing all the I/O.
2423                  */
2424         }
2425
2426         /*
2427          * Testing for -EINPROGRESS is always a bug, so we are bending
2428          * the rules a little.
2429          */
2430         spin_lock_irqsave(sc->lock, flags);
2431         if (sc->work_urb.status == -EINPROGRESS) {      /* janitors: ignore */
2432                 printk(KERN_WARNING "%s: "
2433                     "URB is active after disconnect\n", sc->name);
2434         }
2435         spin_unlock_irqrestore(sc->lock, flags);
2436
2437         /*
2438          * There is virtually no chance that other CPU runs a timeout so long
2439          * after ub_urb_complete should have called del_timer, but only if HCD
2440          * didn't forget to deliver a callback on unlink.
2441          */
2442         del_timer_sync(&sc->work_timer);
2443
2444         /*
2445          * At this point there must be no commands coming from anyone
2446          * and no URBs left in transit.
2447          */
2448
2449         ub_put(sc);
2450 }
2451
2452 static struct usb_driver ub_driver = {
2453         .name =         "ub",
2454         .probe =        ub_probe,
2455         .disconnect =   ub_disconnect,
2456         .id_table =     ub_usb_ids,
2457         .pre_reset =    ub_pre_reset,
2458         .post_reset =   ub_post_reset,
2459 };
2460
2461 static int __init ub_init(void)
2462 {
2463         int rc;
2464         int i;
2465
2466         for (i = 0; i < UB_QLOCK_NUM; i++)
2467                 spin_lock_init(&ub_qlockv[i]);
2468
2469         if ((rc = register_blkdev(UB_MAJOR, DRV_NAME)) != 0)
2470                 goto err_regblkdev;
2471
2472         if ((rc = usb_register(&ub_driver)) != 0)
2473                 goto err_register;
2474
2475         usb_usual_set_present(USB_US_TYPE_UB);
2476         return 0;
2477
2478 err_register:
2479         unregister_blkdev(UB_MAJOR, DRV_NAME);
2480 err_regblkdev:
2481         return rc;
2482 }
2483
2484 static void __exit ub_exit(void)
2485 {
2486         usb_deregister(&ub_driver);
2487
2488         unregister_blkdev(UB_MAJOR, DRV_NAME);
2489         usb_usual_clear_present(USB_US_TYPE_UB);
2490 }
2491
2492 module_init(ub_init);
2493 module_exit(ub_exit);
2494
2495 MODULE_LICENSE("GPL");