aboutsummaryrefslogtreecommitdiff
path: root/drivers/media/video/pvrusb2/pvrusb2-io.c
blob: 1e393762546c174b55c71f967d5c9bdc9f7e65db (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
/*
 *
 *  $Id$
 *
 *  Copyright (C) 2005 Mike Isely <isely@pobox.com>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#include "pvrusb2-io.h"
#include "pvrusb2-debug.h"
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/mutex.h>

static const char *pvr2_buffer_state_decode(enum pvr2_buffer_state);

#define BUFFER_SIG 0x47653271

// #define SANITY_CHECK_BUFFERS


#ifdef SANITY_CHECK_BUFFERS
#define BUFFER_CHECK(bp) do { \
	if ((bp)->signature != BUFFER_SIG) { \
		pvr2_trace(PVR2_TRACE_ERROR_LEGS, \
		"Buffer %p is bad at %s:%d", \
		(bp),__FILE__,__LINE__); \
		pvr2_buffer_describe(bp,"BadSig"); \
		BUG(); \
	} \
} while (0)
#else
#define BUFFER_CHECK(bp) do {} while(0)
#endif

struct pvr2_stream {
	/* Buffers queued for reading */
	struct list_head queued_list;
	unsigned int q_count;
	unsigned int q_bcount;
	/* Buffers with retrieved data */
	struct list_head ready_list;
	unsigned int r_count;
	unsigned int r_bcount;
	/* Buffers available for use */
	struct list_head idle_list;
	unsigned int i_count;
	unsigned int i_bcount;
	/* Pointers to all buffers */
	struct pvr2_buffer **buffers;
	/* Array size of buffers */
	unsigned int buffer_slot_count;
	/* Total buffers actually in circulation */
	unsigned int buffer_total_count;
	/* Designed number of buffers to be in circulation */
	unsigned int buffer_target_count;
	/* Executed when ready list become non-empty */
	pvr2_stream_callback callback_func;
	void *callback_data;
	/* Context for transfer endpoint */
	struct usb_device *dev;
	int endpoint;
	/* Overhead for mutex enforcement */
	spinlock_t list_lock;
	struct mutex mutex;
	/* Tracking state for tolerating errors */
	unsigned int fail_count;
	unsigned int fail_tolerance;
};

struct pvr2_buffer {
	int id;
	int signature;
	enum pvr2_buffer_state state;
	void *ptr;               /* Pointer to storage area */
	unsigned int max_count;  /* Size of storage area */
	unsigned int used_count; /* Amount of valid data in storage area */
	int status;              /* Transfer result status */
	struct pvr2_stream *stream;
	struct list_head list_overhead;
	struct urb *purb;
};

static const char *pvr2_buffer_state_decode(enum pvr2_buffer_state st)
{
	switch (st) {
	case pvr2_buffer_state_none: return "none";
	case pvr2_buffer_state_idle: return "idle";
	case pvr2_buffer_state_queued: return "queued";
	case pvr2_buffer_state_ready: return "ready";
	}
	return "unknown";
}

#ifdef SANITY_CHECK_BUFFERS
static void pvr2_buffer_describe(struct pvr2_buffer *bp,const char *msg)
{
	pvr2_trace(PVR2_TRACE_INFO,
		   "buffer%s%s %p state=%s id=%d status=%d"
		   " stream=%p purb=%p sig=0x%x",
		   (msg ? " " : ""),
		   (msg ? msg : ""),
		   bp,
		   (bp ? pvr2_buffer_state_decode(bp->state) : "(invalid)"),
		   (bp ? bp->id : 0),
		   (bp ? bp->status : 0),
		   (bp ? bp->stream : NULL),
		   (bp ? bp->purb : NULL),
		   (bp ? bp->signature : 0));
}
#endif  /*  SANITY_CHECK_BUFFERS  */

static void pvr2_buffer_remove(struct pvr2_buffer *bp)
{
	unsigned int *cnt;
	unsigned int *bcnt;
	unsigned int ccnt;
	struct pvr2_stream *sp = bp->stream;
	switch (bp->state) {
	case pvr2_buffer_state_idle:
		cnt = &sp->i_count;
		bcnt = &sp->i_bcount;
		ccnt = bp->max_count;
		break;
	case pvr2_buffer_state_queued:
		cnt = &sp->q_count;
		bcnt = &sp->q_bcount;
		ccnt = bp->max_count;
		break;
	case pvr2_buffer_state_ready:
		cnt = &sp->r_count;
		bcnt = &sp->r_bcount;
		ccnt = bp->used_count;
		break;
	default:
		return;
	}
	list_del_init(&bp->list_overhead);
	(*cnt)--;
	(*bcnt) -= ccnt;
	pvr2_trace(PVR2_TRACE_BUF_FLOW,
		   "/*---TRACE_FLOW---*/"
		   " bufferPool     %8s dec cap=%07d cnt=%02d",
		   pvr2_buffer_state_decode(bp->state),*bcnt,*cnt);
	bp->state = pvr2_buffer_state_none;
}

static void pvr2_buffer_set_none(struct pvr2_buffer *bp)
{
	unsigned long irq_flags;
	struct pvr2_stream *sp;
	BUFFER_CHECK(bp);
	sp = bp->stream;
	pvr2_trace(PVR2_TRACE_BUF_FLOW,
		   "/*---TRACE_FLOW---*/ bufferState    %p %6s --> %6s",
		   bp,
		   pvr2_buffer_state_decode(bp->state),
		   pvr2_buffer_state_decode(pvr2_buffer_state_none));
	spin_lock_irqsave(&sp->list_lock,irq_flags);
	pvr2_buffer_remove(bp);
	spin_unlock_irqrestore(&sp->list_lock,irq_flags);
}

static int pvr2_buffer_set_ready(struct pvr2_buffer *bp)
{
	int fl;
	unsigned long irq_flags;
	struct pvr2_stream *sp;
	BUFFER_CHECK(bp);
	sp = bp->stream;
	pvr2_trace(PVR2_TRACE_BUF_FLOW,
		   "/*---TRACE_FLOW---*/ bufferState    %p %6s --> %6s",
		   bp,
		   pvr2_buffer_state_decode(bp->state),
		   pvr2_buffer_state_decode(pvr2_buffer_state_ready));
	spin_lock_irqsave(&sp->list_lock,irq_flags);
	fl = (sp->r_count == 0);
	pvr2_buffer_remove(bp);
	list_add_tail(&bp->list_overhead,&sp->ready_list);
	bp->state = pvr2_buffer_state_ready;
	(sp->r_count)++;
	sp->r_bcount += bp->used_count;
	pvr2_trace(PVR2_TRACE_BUF_FLOW,
		   "/*---TRACE_FLOW---*/"
		   " bufferPool     %8s inc cap=%07d cnt=%02d",
		   pvr2_buffer_state_decode(bp->state),
		   sp->r_bcount,sp->r_count);
	spin_unlock_irqrestore(&sp->list_lock,irq_flags);
	return fl;
}

static void pvr2_buffer_set_idle(struct pvr2_buffer *bp)
{
	unsigned long irq_flags;
	struct pvr2_stream *sp;
	BUFFER_CHECK(bp);
	sp = bp->stream;
	pvr2_trace(PVR2_TRACE_BUF_FLOW,
		   "/*---TRACE_FLOW---*/ bufferState    %p %6s --> %6s",
		   bp,
		   pvr2_buffer_state_decode(bp->state),
		   pvr2_buffer_state_decode(pvr2_buffer_state_idle));
	spin_lock_irqsave(&sp->list_lock,irq_flags);
	pvr2_buffer_remove(bp);
	list_add_tail(&bp->list_overhead,&sp->idle_list);
	bp->state = pvr2_buffer_state_idle;
	(sp->i_count)++;
	sp->i_bcount += bp->max_count;
	pvr2_trace(PVR2_TRACE_BUF_FLOW,
		   "/*---TRACE_FLOW---*/"
		   " bufferPool     %8s inc cap=%07d cnt=%02d",
		   pvr2_buffer_state_decode(bp->state),
		   sp->i_bcount,sp->i_count);
	spin_unlock_irqrestore(&sp->list_lock,irq_flags);
}

static void pvr2_buffer_set_queued(struct pvr2_buffer *bp)
{
	unsigned long irq_flags;
	struct pvr2_stream *sp;
	BUFFER_CHECK(bp);
	sp = bp->stream;
	pvr2_trace(PVR2_TRACE_BUF_FLOW,
		   "/*---TRACE_FLOW---*/ bufferState    %p %6s --> %6s",
		   bp,
		   pvr2_buffer_state_decode(bp->state),
		   pvr2_buffer_state_decode(pvr2_buffer_state_queued));
	spin_lock_irqsave(&sp->list_lock,irq_flags);
	pvr2_buffer_remove(bp);
	list_add_tail(&bp->list_overhead,&sp->queued_list);
	bp->state = pvr2_buffer_state_queued;
	(sp->q_count)++;
	sp->q_bcount += bp->max_count;
	pvr2_trace(PVR2_TRACE_BUF_FLOW,
		   "/*---TRACE_FLOW---*/"
		   " bufferPool     %8s inc cap=%07d cnt=%02d",
		   pvr2_buffer_state_decode(bp->state),
		   sp->q_bcount,sp->q_count);
	spin_unlock_irqrestore(&sp->list_lock,irq_flags);
}

static void pvr2_buffer_wipe(struct pvr2_buffer *bp)
{
	if (bp->state == pvr2_buffer_state_queued) {
		usb_kill_urb(bp->purb);
	}
}

static int pvr2_buffer_init(struct pvr2_buffer *bp,
			    struct pvr2_stream *sp,
			    unsigned int id)
{
	memset(bp,0,sizeof(*bp));
	bp->signature = BUFFER_SIG;
	bp->id = id;
	pvr2_trace(PVR2_TRACE_BUF_POOL,
		   "/*---TRACE_FLOW---*/ bufferInit     %p stream=%p",bp,sp);
	bp->stream = sp;
	bp->state = pvr2_buffer_state_none;
	INIT_LIST_HEAD(&bp->list_overhead);
	bp->purb = usb_alloc_urb(0,GFP_KERNEL);
	if (! bp->purb) return -ENOMEM;
#ifdef SANITY_CHECK_BUFFERS
	pvr2_buffer_describe(bp,"create");
#endif
	return 0;
}

static void pvr2_buffer_done(struct pvr2_buffer *bp)
{
#ifdef SANITY_CHECK_BUFFERS
	pvr2_buffer_describe(bp,"delete");
#endif
	pvr2_buffer_wipe(bp);
	pvr2_buffer_set_none(bp);
	bp->signature = 0;
	bp->stream = NULL;
	if (bp->purb) usb_free_urb(bp->purb);
	pvr2_trace(PVR2_TRACE_BUF_POOL,"/*---TRACE_FLOW---*/"
		   " bufferDone     %p",bp);
}

static int pvr2_stream_buffer_count(struct pvr2_stream *sp,unsigned int cnt)
{
	int ret;
	unsigned int scnt;

	/* Allocate buffers pointer array in multiples of 32 entries */
	if (cnt == sp->buffer_total_count) return 0;

	pvr2_trace(PVR2_TRACE_BUF_POOL,
		   "/*---TRACE_FLOW---*/ poolResize    "
		   " stream=%p cur=%d adj=%+d",
		   sp,
		   sp->buffer_total_count,
		   cnt-sp->buffer_total_count);

	scnt = cnt & ~0x1f;
	if (cnt > scnt) scnt += 0x20;

	if (cnt > sp->buffer_total_count) {
		if (scnt > sp->buffer_slot_count) {
			struct pvr2_buffer **nb;
			nb = kmalloc(scnt * sizeof(*nb),GFP_KERNEL);
			if (!nb) return -ENOMEM;
			if (sp->buffer_slot_count) {
				memcpy(nb,sp->buffers,
				       sp->buffer_slot_count * sizeof(*nb));
				kfree(sp->buffers);
			}
			sp->buffers = nb;
			sp->buffer_slot_count = scnt;
		}
		while (sp->buffer_total_count < cnt) {
			struct pvr2_buffer *bp;
			bp = kmalloc(sizeof(*bp),GFP_KERNEL);
			if (!bp) return -ENOMEM;
			ret = pvr2_buffer_init(bp,sp,sp->buffer_total_count);
			if (ret) {
				kfree(bp);
				return -ENOMEM;
			}
			sp->buffers[sp->buffer_total_count] = bp;
			(sp->buffer_total_count)++;
			pvr2_buffer_set_idle(bp);
		}
	} else {
		while (sp->buffer_total_count > cnt) {
			struct pvr2_buffer *bp;
			bp = sp->buffers[sp->buffer_total_count - 1];
			/* Paranoia */
			sp->buffers[sp->buffer_total_count - 1] = NULL;
			(sp->buffer_total_count)--;
			pvr2_buffer_done(bp);
			kfree(bp);
		}
		if (scnt < sp->buffer_slot_count) {
			struct pvr2_buffer **nb = NULL;
			if (scnt) {
				nb = kmalloc(scnt * sizeof(*nb),GFP_KERNEL);
				if (!nb) return -ENOMEM;
				memcpy(nb,sp->buffers,scnt * sizeof(*nb));
			}
			kfree(sp->buffers);
			sp->buffers = nb;
			sp->buffer_slot_count = scnt;
		}
	}
	return 0;
}

static int pvr2_stream_achieve_buffer_count(struct pvr2_stream *sp)
{
	struct pvr2_buffer *bp;
	unsigned int cnt;

	if (sp->buffer_total_count == sp->buffer_target_count) return 0;

	pvr2_trace(PVR2_TRACE_BUF_POOL,
		   "/*---TRACE_FLOW---*/"
		   " poolCheck      stream=%p cur=%d tgt=%d",
		   sp,sp->buffer_total_count,sp->buffer_target_count);

	if (sp->buffer_total_count < sp->buffer_target_count) {
		return pvr2_stream_buffer_count(sp,sp->buffer_target_count);
	}

	cnt = 0;
	while ((sp->buffer_total_count - cnt) > sp->buffer_target_count) {
		bp = sp->buffers[sp->buffer_total_count - (cnt + 1)];
		if (bp->state != pvr2_buffer_state_idle) break;
		cnt++;
	}
	if (cnt) {
		pvr2_stream_buffer_count(sp,sp->buffer_total_count - cnt);
	}

	return 0;
}

static void pvr2_stream_internal_flush(struct pvr2_stream *sp)
{
	struct list_head *lp;
	struct pvr2_buffer *bp1;
	while ((lp = sp->queued_list.next) != &sp->queued_list) {
		bp1 = list_entry(lp,struct pvr2_buffer,list_overhead);
		pvr2_buffer_wipe(bp1);
		/* At this point, we should be guaranteed that no
		   completion callback may happen on this buffer.  But it's
		   possible that it might have completed after we noticed
		   it but before we wiped it.  So double check its status
		   here first. */
		if (bp1->state != pvr2_buffer_state_queued) continue;
		pvr2_buffer_set_idle(bp1);
	}
	if (sp->buffer_total_count != sp->buffer_target_count) {
		pvr2_stream_achieve_buffer_count(sp);
	}
}

static void pvr2_stream_init(struct pvr2_stream *sp)
{
	spin_lock_init(&sp->list_lock);
	mutex_init(&sp->mutex);
	INIT_LIST_HEAD(&sp->queued_list);
	INIT_LIST_HEAD(&sp->ready_list);
	INIT_LIST_HEAD(&sp->idle_list);
}

static void pvr2_stream_done(struct pvr2_stream *sp)
{
	mutex_lock(&sp->mutex); do {
		pvr2_stream_internal_flush(sp);
		pvr2_stream_buffer_count(sp,0);
	} while (0); mutex_unlock(&sp->mutex);
}

static void buffer_complete(struct urb *urb, struct pt_regs *regs)
{
	struct pvr2_buffer *bp = urb->context;
	struct pvr2_stream *sp;
	unsigned long irq_flags;
	BUFFER_CHECK(bp);
	sp = bp->stream;
	bp->used_count = 0;
	bp->status = 0;
	pvr2_trace(PVR2_TRACE_BUF_FLOW,
		   "/*---TRACE_FLOW---*/ bufferComplete %p stat=%d cnt=%d",
		   bp,urb->status,urb->actual_length);
	spin_lock_irqsave(&sp->list_lock,irq_flags);
	if ((!(urb->status)) ||
	    (urb->status == -ENOENT) ||
	    (urb->status == -ECONNRESET) ||
	    (urb->status == -ESHUTDOWN)) {
		bp->used_count = urb->actual_length;
		if (sp->fail_count) {
			pvr2_trace(PVR2_TRACE_TOLERANCE,
				   "stream %p transfer ok"
				   " - fail count reset",sp);
			sp->fail_count = 0;
		}
	} else if (sp->fail_count < sp->fail_tolerance) {
		// We can tolerate this error, because we're below the
		// threshold...
		(sp->fail_count)++;
		pvr2_trace(PVR2_TRACE_TOLERANCE,
			   "stream %p ignoring error %d"
			   " - fail count increased to %u",
			   sp,urb->status,sp->fail_count);
	} else {
		bp->status = urb->status;
	}
	spin_unlock_irqrestore(&sp->list_lock,irq_flags);
	pvr2_buffer_set_ready(bp);
	if (sp && sp->callback_func) {
		sp->callback_func(sp->callback_data);
	}
}

struct pvr2_stream *pvr2_stream_create(void)
{
	struct pvr2_stream *sp;
	sp = kmalloc(sizeof(*sp),GFP_KERNEL);
	if (!sp) return sp;
	memset(sp,0,sizeof(*sp));
	pvr2_trace(PVR2_TRACE_INIT,"pvr2_stream_create: sp=%p",sp);
	pvr2_stream_init(sp);
	return sp;
}

void pvr2_stream_destroy(struct pvr2_stream *sp)
{
	if (!sp) return;
	pvr2_trace(PVR2_TRACE_INIT,"pvr2_stream_destroy: sp=%p",sp);
	pvr2_stream_done(sp);
	kfree(sp);
}

void pvr2_stream_setup(struct pvr2_stream *sp,
		       struct usb_device *dev,
		       int endpoint,
		       unsigned int tolerance)
{
	mutex_lock(&sp->mutex); do {
		pvr2_stream_internal_flush(sp);
		sp->dev = dev;
		sp->endpoint = endpoint;
		sp->fail_tolerance = tolerance;
	} while(0); mutex_unlock(&sp->mutex);
}

void pvr2_stream_set_callback(struct pvr2_stream *sp,
			      pvr2_stream_callback func,
			      void *data)
{
	unsigned long irq_flags;
	mutex_lock(&sp->mutex); do {
		spin_lock_irqsave(&sp->list_lock,irq_flags);
		sp->callback_data = data;
		sp->callback_func = func;
		spin_unlock_irqrestore(&sp->list_lock,irq_flags);
	} while(0); mutex_unlock(&sp->mutex);
}

/* Query / set the nominal buffer count */
int pvr2_stream_get_buffer_count(struct pvr2_stream *sp)
{
	return sp->buffer_target_count;
}

int pvr2_stream_set_buffer_count(struct pvr2_stream *sp,unsigned int cnt)
{
	int ret;
	if (sp->buffer_target_count == cnt) return 0;
	mutex_lock(&sp->mutex); do {
		sp->buffer_target_count = cnt;
		ret = pvr2_stream_achieve_buffer_count(sp);
	} while(0); mutex_unlock(&sp->mutex);
	return ret;
}

struct pvr2_buffer *pvr2_stream_get_idle_buffer(struct pvr2_stream *sp)
{
	struct list_head *lp = sp->idle_list.next;
	if (lp == &sp->idle_list) return NULL;
	return list_entry(lp,struct pvr2_buffer,list_overhead);
}

struct pvr2_buffer *pvr2_stream_get_ready_buffer(struct pvr2_stream *sp)
{
	struct list_head *lp = sp->ready_list.next;
	if (lp == &sp->ready_list) return NULL;
	return list_entry(lp,struct pvr2_buffer,list_overhead);
}

struct pvr2_buffer *pvr2_stream_get_buffer(struct pvr2_stream *sp,int id)
{
	if (id < 0) return NULL;
	if (id >= sp->buffer_total_count) return NULL;
	return sp->buffers[id];
}

int pvr2_stream_get_ready_count(struct pvr2_stream *sp)
{
	return sp->r_count;
}

void pvr2_stream_kill(struct pvr2_stream *sp)
{
	struct pvr2_buffer *bp;
	mutex_lock(&sp->mutex); do {
		pvr2_stream_internal_flush(sp);
		while ((bp = pvr2_stream_get_ready_buffer(sp)) != 0) {
			pvr2_buffer_set_idle(bp);
		}
		if (sp->buffer_total_count != sp->buffer_target_count) {
			pvr2_stream_achieve_buffer_count(sp);
		}
	} while(0); mutex_unlock(&sp->mutex);
}

int pvr2_buffer_queue(struct pvr2_buffer *bp)
{
#undef SEED_BUFFER
#ifdef SEED_BUFFER
	unsigned int idx;
	unsigned int val;
#endif
	int ret = 0;
	struct pvr2_stream *sp;
	if (!bp) return -EINVAL;
	sp = bp->stream;
	mutex_lock(&sp->mutex); do {
		pvr2_buffer_wipe(bp);
		if (!sp->dev) {
			ret = -EIO;
			break;
		}
		pvr2_buffer_set_queued(bp);
#ifdef SEED_BUFFER
		for (idx = 0; idx < (bp->max_count) / 4; idx++) {
			val = bp->id << 24;
			val |= idx;
			((unsigned int *)(bp->ptr))[idx] = val;
		}
#endif
		bp->status = -EINPROGRESS;
		usb_fill_bulk_urb(bp->purb,      // struct urb *urb
				  sp->dev,       // struct usb_device *dev
				  // endpoint (below)
				  usb_rcvbulkpipe(sp->dev,sp->endpoint),
				  bp->ptr,       // void *transfer_buffer
				  bp->max_count, // int buffer_length
				  buffer_complete,
				  bp);
		usb_submit_urb(bp->purb,GFP_KERNEL);
	} while(0); mutex_unlock(&sp->mutex);
	return ret;
}

int pvr2_buffer_set_buffer(struct pvr2_buffer *bp,void *ptr,unsigned int cnt)
{
	int ret = 0;
	unsigned long irq_flags;
	struct pvr2_stream *sp;
	if (!bp) return -EINVAL;
	sp = bp->stream;
	mutex_lock(&sp->mutex); do {
		spin_lock_irqsave(&sp->list_lock,irq_flags);
		if (bp->state != pvr2_buffer_state_idle) {
			ret = -EPERM;
		} else {
			bp->ptr = ptr;
			bp->stream->i_bcount -= bp->max_count;
			bp->max_count = cnt;
			bp->stream->i_bcount += bp->max_count;
			pvr2_trace(PVR2_TRACE_BUF_FLOW,
				   "/*---TRACE_FLOW---*/ bufferPool    "
				   " %8s cap cap=%07d cnt=%02d",
				   pvr2_buffer_state_decode(
					   pvr2_buffer_state_idle),
				   bp->stream->i_bcount,bp->stream->i_count);
		}
		spin_unlock_irqrestore(&sp->list_lock,irq_flags);
	} while(0); mutex_unlock(&sp->mutex);
	return ret;
}

unsigned int pvr2_buffer_get_count(struct pvr2_buffer *bp)
{
	return bp->used_count;
}

int pvr2_buffer_get_status(struct pvr2_buffer *bp)
{
	return bp->status;
}

int pvr2_buffer_get_id(struct pvr2_buffer *bp)
{
	return bp->id;
}


/*
  Stuff for Emacs to see, in order to encourage consistent editing style:
  *** Local Variables: ***
  *** mode: c ***
  *** fill-column: 75 ***
  *** tab-width: 8 ***
  *** c-basic-offset: 8 ***
  *** End: ***
  */