Root/drivers/block/ub.c

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

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