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[PATCH] USB: ehci: microframe handling fix
[linux-2.6/verdex.git] / arch / arm / common / dmabounce.c
blobcbf2165476b09df908799fa7660e9c9e5681ac17
1 /*
2 * arch/arm/common/dmabounce.c
3 *
4 * Special dma_{map/unmap/dma_sync}_* routines for systems that have
5 * limited DMA windows. These functions utilize bounce buffers to
6 * copy data to/from buffers located outside the DMA region. This
7 * only works for systems in which DMA memory is at the bottom of
8 * RAM and the remainder of memory is at the top an the DMA memory
9 * can be marked as ZONE_DMA. Anything beyond that such as discontigous
10 * DMA windows will require custom implementations that reserve memory
11 * areas at early bootup.
12 *
13 * Original version by Brad Parker (brad@heeltoe.com)
14 * Re-written by Christopher Hoover <ch@murgatroid.com>
15 * Made generic by Deepak Saxena <dsaxena@plexity.net>
16 *
17 * Copyright (C) 2002 Hewlett Packard Company.
18 * Copyright (C) 2004 MontaVista Software, Inc.
19 *
20 * This program is free software; you can redistribute it and/or
21 * modify it under the terms of the GNU General Public License
22 * version 2 as published by the Free Software Foundation.
23 */
24
25 #include <linux/module.h>
26 #include <linux/init.h>
27 #include <linux/slab.h>
28 #include <linux/device.h>
29 #include <linux/dma-mapping.h>
30 #include <linux/dmapool.h>
31 #include <linux/list.h>
32
33 #include <asm/cacheflush.h>
34
35 #undef DEBUG
36
37 #undef STATS
38 #ifdef STATS
39 #define DO_STATS(X) do { X ; } while (0)
40 #else
41 #define DO_STATS(X) do { } while (0)
42 #endif
43
44 /* ************************************************** */
45
46 struct safe_buffer {
47 struct list_head node;
48
49 /* original request */
50 void *ptr;
51 size_t size;
52 int direction;
53
54 /* safe buffer info */
55 struct dma_pool *pool;
56 void *safe;
57 dma_addr_t safe_dma_addr;
58 };
59
60 struct dmabounce_device_info {
61 struct list_head node;
62
63 struct device *dev;
64 struct dma_pool *small_buffer_pool;
65 struct dma_pool *large_buffer_pool;
66 struct list_head safe_buffers;
67 unsigned long small_buffer_size, large_buffer_size;
68 #ifdef STATS
69 unsigned long sbp_allocs;
70 unsigned long lbp_allocs;
71 unsigned long total_allocs;
72 unsigned long map_op_count;
73 unsigned long bounce_count;
74 #endif
75 };
76
77 static LIST_HEAD(dmabounce_devs);
78
79 #ifdef STATS
80 static void print_alloc_stats(struct dmabounce_device_info *device_info)
81 {
82 printk(KERN_INFO
83 "%s: dmabounce: sbp: %lu, lbp: %lu, other: %lu, total: %lu\n",
84 device_info->dev->bus_id,
85 device_info->sbp_allocs, device_info->lbp_allocs,
86 device_info->total_allocs - device_info->sbp_allocs -
87 device_info->lbp_allocs,
88 device_info->total_allocs);
89 }
90 #endif
91
92 /* find the given device in the dmabounce device list */
93 static inline struct dmabounce_device_info *
94 find_dmabounce_dev(struct device *dev)
95 {
96 struct dmabounce_device_info *d;
97
98 list_for_each_entry(d, &dmabounce_devs, node)
99 if (d->dev == dev)
100 return d;
101
102 return NULL;
103 }
104
105
106 /* allocate a 'safe' buffer and keep track of it */
107 static inline struct safe_buffer *
108 alloc_safe_buffer(struct dmabounce_device_info *device_info, void *ptr,
109 size_t size, enum dma_data_direction dir)
110 {
111 struct safe_buffer *buf;
112 struct dma_pool *pool;
113 struct device *dev = device_info->dev;
114 void *safe;
115 dma_addr_t safe_dma_addr;
116
117 dev_dbg(dev, "%s(ptr=%p, size=%d, dir=%d)\n",
118 __func__, ptr, size, dir);
119
120 DO_STATS ( device_info->total_allocs++ );
121
122 buf = kmalloc(sizeof(struct safe_buffer), GFP_ATOMIC);
123 if (buf == NULL) {
124 dev_warn(dev, "%s: kmalloc failed\n", __func__);
125 return NULL;
126 }
127
128 if (size <= device_info->small_buffer_size) {
129 pool = device_info->small_buffer_pool;
130 safe = dma_pool_alloc(pool, GFP_ATOMIC, &safe_dma_addr);
131
132 DO_STATS ( device_info->sbp_allocs++ );
133 } else if (size <= device_info->large_buffer_size) {
134 pool = device_info->large_buffer_pool;
135 safe = dma_pool_alloc(pool, GFP_ATOMIC, &safe_dma_addr);
136
137 DO_STATS ( device_info->lbp_allocs++ );
138 } else {
139 pool = NULL;
140 safe = dma_alloc_coherent(dev, size, &safe_dma_addr, GFP_ATOMIC);
141 }
142
143 if (safe == NULL) {
144 dev_warn(device_info->dev,
145 "%s: could not alloc dma memory (size=%d)\n",
146 __func__, size);
147 kfree(buf);
148 return NULL;
149 }
150
151 #ifdef STATS
152 if (device_info->total_allocs % 1000 == 0)
153 print_alloc_stats(device_info);
154 #endif
155
156 buf->ptr = ptr;
157 buf->size = size;
158 buf->direction = dir;
159 buf->pool = pool;
160 buf->safe = safe;
161 buf->safe_dma_addr = safe_dma_addr;
162
163 list_add(&buf->node, &device_info->safe_buffers);
164
165 return buf;
166 }
167
168 /* determine if a buffer is from our "safe" pool */
169 static inline struct safe_buffer *
170 find_safe_buffer(struct dmabounce_device_info *device_info, dma_addr_t safe_dma_addr)
171 {
172 struct safe_buffer *b;
173
174 list_for_each_entry(b, &device_info->safe_buffers, node)
175 if (b->safe_dma_addr == safe_dma_addr)
176 return b;
177
178 return NULL;
179 }
180
181 static inline void
182 free_safe_buffer(struct dmabounce_device_info *device_info, struct safe_buffer *buf)
183 {
184 dev_dbg(device_info->dev, "%s(buf=%p)\n", __func__, buf);
185
186 list_del(&buf->node);
187
188 if (buf->pool)
189 dma_pool_free(buf->pool, buf->safe, buf->safe_dma_addr);
190 else
191 dma_free_coherent(device_info->dev, buf->size, buf->safe,
192 buf->safe_dma_addr);
193
194 kfree(buf);
195 }
196
197 /* ************************************************** */
198
199 #ifdef STATS
200
201 static void print_map_stats(struct dmabounce_device_info *device_info)
202 {
203 printk(KERN_INFO
204 "%s: dmabounce: map_op_count=%lu, bounce_count=%lu\n",
205 device_info->dev->bus_id,
206 device_info->map_op_count, device_info->bounce_count);
207 }
208 #endif
209
210 static inline dma_addr_t
211 map_single(struct device *dev, void *ptr, size_t size,
212 enum dma_data_direction dir)
213 {
214 struct dmabounce_device_info *device_info = find_dmabounce_dev(dev);
215 dma_addr_t dma_addr;
216 int needs_bounce = 0;
217
218 if (device_info)
219 DO_STATS ( device_info->map_op_count++ );
220
221 dma_addr = virt_to_dma(dev, ptr);
222
223 if (dev->dma_mask) {
224 unsigned long mask = *dev->dma_mask;
225 unsigned long limit;
226
227 limit = (mask + 1) & ~mask;
228 if (limit && size > limit) {
229 dev_err(dev, "DMA mapping too big (requested %#x "
230 "mask %#Lx)\n", size, *dev->dma_mask);
231 return ~0;
232 }
233
234 /*
235 * Figure out if we need to bounce from the DMA mask.
236 */
237 needs_bounce = (dma_addr | (dma_addr + size - 1)) & ~mask;
238 }
239
240 if (device_info && (needs_bounce || dma_needs_bounce(dev, dma_addr, size))) {
241 struct safe_buffer *buf;
242
243 buf = alloc_safe_buffer(device_info, ptr, size, dir);
244 if (buf == 0) {
245 dev_err(dev, "%s: unable to map unsafe buffer %p!\n",
246 __func__, ptr);
247 return 0;
248 }
249
250 dev_dbg(dev,
251 "%s: unsafe buffer %p (phy=%p) mapped to %p (phy=%p)\n",
252 __func__, buf->ptr, (void *) virt_to_dma(dev, buf->ptr),
253 buf->safe, (void *) buf->safe_dma_addr);
254
255 if ((dir == DMA_TO_DEVICE) ||
256 (dir == DMA_BIDIRECTIONAL)) {
257 dev_dbg(dev, "%s: copy unsafe %p to safe %p, size %d\n",
258 __func__, ptr, buf->safe, size);
259 memcpy(buf->safe, ptr, size);
260 }
261 consistent_sync(buf->safe, size, dir);
262
263 dma_addr = buf->safe_dma_addr;
264 } else {
265 consistent_sync(ptr, size, dir);
266 }
267
268 return dma_addr;
269 }
270
271 static inline void
272 unmap_single(struct device *dev, dma_addr_t dma_addr, size_t size,
273 enum dma_data_direction dir)
274 {
275 struct dmabounce_device_info *device_info = find_dmabounce_dev(dev);
276 struct safe_buffer *buf = NULL;
277
278 /*
279 * Trying to unmap an invalid mapping
280 */
281 if (dma_addr == ~0) {
282 dev_err(dev, "Trying to unmap invalid mapping\n");
283 return;
284 }
285
286 if (device_info)
287 buf = find_safe_buffer(device_info, dma_addr);
288
289 if (buf) {
290 BUG_ON(buf->size != size);
291
292 dev_dbg(dev,
293 "%s: unsafe buffer %p (phy=%p) mapped to %p (phy=%p)\n",
294 __func__, buf->ptr, (void *) virt_to_dma(dev, buf->ptr),
295 buf->safe, (void *) buf->safe_dma_addr);
296
297 DO_STATS ( device_info->bounce_count++ );
298
299 if (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL) {
300 unsigned long ptr;
301
302 dev_dbg(dev,
303 "%s: copy back safe %p to unsafe %p size %d\n",
304 __func__, buf->safe, buf->ptr, size);
305 memcpy(buf->ptr, buf->safe, size);
306
307 /*
308 * DMA buffers must have the same cache properties
309 * as if they were really used for DMA - which means
310 * data must be written back to RAM. Note that
311 * we don't use dmac_flush_range() here for the
312 * bidirectional case because we know the cache
313 * lines will be coherent with the data written.
314 */
315 ptr = (unsigned long)buf->ptr;
316 dmac_clean_range(ptr, ptr + size);
317 }
318 free_safe_buffer(device_info, buf);
319 }
320 }
321
322 static inline void
323 sync_single(struct device *dev, dma_addr_t dma_addr, size_t size,
324 enum dma_data_direction dir)
325 {
326 struct dmabounce_device_info *device_info = find_dmabounce_dev(dev);
327 struct safe_buffer *buf = NULL;
328
329 if (device_info)
330 buf = find_safe_buffer(device_info, dma_addr);
331
332 if (buf) {
333 /*
334 * Both of these checks from original code need to be
335 * commented out b/c some drivers rely on the following:
336 *
337 * 1) Drivers may map a large chunk of memory into DMA space
338 * but only sync a small portion of it. Good example is
339 * allocating a large buffer, mapping it, and then
340 * breaking it up into small descriptors. No point
341 * in syncing the whole buffer if you only have to
342 * touch one descriptor.
343 *
344 * 2) Buffers that are mapped as DMA_BIDIRECTIONAL are
345 * usually only synced in one dir at a time.
346 *
347 * See drivers/net/eepro100.c for examples of both cases.
348 *
349 * -ds
350 *
351 * BUG_ON(buf->size != size);
352 * BUG_ON(buf->direction != dir);
353 */
354
355 dev_dbg(dev,
356 "%s: unsafe buffer %p (phy=%p) mapped to %p (phy=%p)\n",
357 __func__, buf->ptr, (void *) virt_to_dma(dev, buf->ptr),
358 buf->safe, (void *) buf->safe_dma_addr);
359
360 DO_STATS ( device_info->bounce_count++ );
361
362 switch (dir) {
363 case DMA_FROM_DEVICE:
364 dev_dbg(dev,
365 "%s: copy back safe %p to unsafe %p size %d\n",
366 __func__, buf->safe, buf->ptr, size);
367 memcpy(buf->ptr, buf->safe, size);
368 break;
369 case DMA_TO_DEVICE:
370 dev_dbg(dev,
371 "%s: copy out unsafe %p to safe %p, size %d\n",
372 __func__,buf->ptr, buf->safe, size);
373 memcpy(buf->safe, buf->ptr, size);
374 break;
375 case DMA_BIDIRECTIONAL:
376 BUG(); /* is this allowed? what does it mean? */
377 default:
378 BUG();
379 }
380 consistent_sync(buf->safe, size, dir);
381 } else {
382 consistent_sync(dma_to_virt(dev, dma_addr), size, dir);
383 }
384 }
385
386 /* ************************************************** */
387
388 /*
389 * see if a buffer address is in an 'unsafe' range. if it is
390 * allocate a 'safe' buffer and copy the unsafe buffer into it.
391 * substitute the safe buffer for the unsafe one.
392 * (basically move the buffer from an unsafe area to a safe one)
393 */
394 dma_addr_t
395 dma_map_single(struct device *dev, void *ptr, size_t size,
396 enum dma_data_direction dir)
397 {
398 unsigned long flags;
399 dma_addr_t dma_addr;
400
401 dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n",
402 __func__, ptr, size, dir);
403
404 BUG_ON(dir == DMA_NONE);
405
406 local_irq_save(flags);
407
408 dma_addr = map_single(dev, ptr, size, dir);
409
410 local_irq_restore(flags);
411
412 return dma_addr;
413 }
414
415 /*
416 * see if a mapped address was really a "safe" buffer and if so, copy
417 * the data from the safe buffer back to the unsafe buffer and free up
418 * the safe buffer. (basically return things back to the way they
419 * should be)
420 */
421
422 void
423 dma_unmap_single(struct device *dev, dma_addr_t dma_addr, size_t size,
424 enum dma_data_direction dir)
425 {
426 unsigned long flags;
427
428 dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n",
429 __func__, (void *) dma_addr, size, dir);
430
431 BUG_ON(dir == DMA_NONE);
432
433 local_irq_save(flags);
434
435 unmap_single(dev, dma_addr, size, dir);
436
437 local_irq_restore(flags);
438 }
439
440 int
441 dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
442 enum dma_data_direction dir)
443 {
444 unsigned long flags;
445 int i;
446
447 dev_dbg(dev, "%s(sg=%p,nents=%d,dir=%x)\n",
448 __func__, sg, nents, dir);
449
450 BUG_ON(dir == DMA_NONE);
451
452 local_irq_save(flags);
453
454 for (i = 0; i < nents; i++, sg++) {
455 struct page *page = sg->page;
456 unsigned int offset = sg->offset;
457 unsigned int length = sg->length;
458 void *ptr = page_address(page) + offset;
459
460 sg->dma_address =
461 map_single(dev, ptr, length, dir);
462 }
463
464 local_irq_restore(flags);
465
466 return nents;
467 }
468
469 void
470 dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,
471 enum dma_data_direction dir)
472 {
473 unsigned long flags;
474 int i;
475
476 dev_dbg(dev, "%s(sg=%p,nents=%d,dir=%x)\n",
477 __func__, sg, nents, dir);
478
479 BUG_ON(dir == DMA_NONE);
480
481 local_irq_save(flags);
482
483 for (i = 0; i < nents; i++, sg++) {
484 dma_addr_t dma_addr = sg->dma_address;
485 unsigned int length = sg->length;
486
487 unmap_single(dev, dma_addr, length, dir);
488 }
489
490 local_irq_restore(flags);
491 }
492
493 void
494 dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_addr, size_t size,
495 enum dma_data_direction dir)
496 {
497 unsigned long flags;
498
499 dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n",
500 __func__, (void *) dma_addr, size, dir);
501
502 local_irq_save(flags);
503
504 sync_single(dev, dma_addr, size, dir);
505
506 local_irq_restore(flags);
507 }
508
509 void
510 dma_sync_single_for_device(struct device *dev, dma_addr_t dma_addr, size_t size,
511 enum dma_data_direction dir)
512 {
513 unsigned long flags;
514
515 dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n",
516 __func__, (void *) dma_addr, size, dir);
517
518 local_irq_save(flags);
519
520 sync_single(dev, dma_addr, size, dir);
521
522 local_irq_restore(flags);
523 }
524
525 void
526 dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg, int nents,
527 enum dma_data_direction dir)
528 {
529 unsigned long flags;
530 int i;
531
532 dev_dbg(dev, "%s(sg=%p,nents=%d,dir=%x)\n",
533 __func__, sg, nents, dir);
534
535 BUG_ON(dir == DMA_NONE);
536
537 local_irq_save(flags);
538
539 for (i = 0; i < nents; i++, sg++) {
540 dma_addr_t dma_addr = sg->dma_address;
541 unsigned int length = sg->length;
542
543 sync_single(dev, dma_addr, length, dir);
544 }
545
546 local_irq_restore(flags);
547 }
548
549 void
550 dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg, int nents,
551 enum dma_data_direction dir)
552 {
553 unsigned long flags;
554 int i;
555
556 dev_dbg(dev, "%s(sg=%p,nents=%d,dir=%x)\n",
557 __func__, sg, nents, dir);
558
559 BUG_ON(dir == DMA_NONE);
560
561 local_irq_save(flags);
562
563 for (i = 0; i < nents; i++, sg++) {
564 dma_addr_t dma_addr = sg->dma_address;
565 unsigned int length = sg->length;
566
567 sync_single(dev, dma_addr, length, dir);
568 }
569
570 local_irq_restore(flags);
571 }
572
573 int
574 dmabounce_register_dev(struct device *dev, unsigned long small_buffer_size,
575 unsigned long large_buffer_size)
576 {
577 struct dmabounce_device_info *device_info;
578
579 device_info = kmalloc(sizeof(struct dmabounce_device_info), GFP_ATOMIC);
580 if (!device_info) {
581 printk(KERN_ERR
582 "Could not allocated dmabounce_device_info for %s",
583 dev->bus_id);
584 return -ENOMEM;
585 }
586
587 device_info->small_buffer_pool =
588 dma_pool_create("small_dmabounce_pool",
589 dev,
590 small_buffer_size,
591 0 /* byte alignment */,
592 0 /* no page-crossing issues */);
593 if (!device_info->small_buffer_pool) {
594 printk(KERN_ERR
595 "dmabounce: could not allocate small DMA pool for %s\n",
596 dev->bus_id);
597 kfree(device_info);
598 return -ENOMEM;
599 }
600
601 if (large_buffer_size) {
602 device_info->large_buffer_pool =
603 dma_pool_create("large_dmabounce_pool",
604 dev,
605 large_buffer_size,
606 0 /* byte alignment */,
607 0 /* no page-crossing issues */);
608 if (!device_info->large_buffer_pool) {
609 printk(KERN_ERR
610 "dmabounce: could not allocate large DMA pool for %s\n",
611 dev->bus_id);
612 dma_pool_destroy(device_info->small_buffer_pool);
613
614 return -ENOMEM;
615 }
616 }
617
618 device_info->dev = dev;
619 device_info->small_buffer_size = small_buffer_size;
620 device_info->large_buffer_size = large_buffer_size;
621 INIT_LIST_HEAD(&device_info->safe_buffers);
622
623 #ifdef STATS
624 device_info->sbp_allocs = 0;
625 device_info->lbp_allocs = 0;
626 device_info->total_allocs = 0;
627 device_info->map_op_count = 0;
628 device_info->bounce_count = 0;
629 #endif
630
631 list_add(&device_info->node, &dmabounce_devs);
632
633 printk(KERN_INFO "dmabounce: registered device %s on %s bus\n",
634 dev->bus_id, dev->bus->name);
635
636 return 0;
637 }
638
639 void
640 dmabounce_unregister_dev(struct device *dev)
641 {
642 struct dmabounce_device_info *device_info = find_dmabounce_dev(dev);
643
644 if (!device_info) {
645 printk(KERN_WARNING
646 "%s: Never registered with dmabounce but attempting" \
647 "to unregister!\n", dev->bus_id);
648 return;
649 }
650
651 if (!list_empty(&device_info->safe_buffers)) {
652 printk(KERN_ERR
653 "%s: Removing from dmabounce with pending buffers!\n",
654 dev->bus_id);
655 BUG();
656 }
657
658 if (device_info->small_buffer_pool)
659 dma_pool_destroy(device_info->small_buffer_pool);
660 if (device_info->large_buffer_pool)
661 dma_pool_destroy(device_info->large_buffer_pool);
662
663 #ifdef STATS
664 print_alloc_stats(device_info);
665 print_map_stats(device_info);
666 #endif
667
668 list_del(&device_info->node);
669
670 kfree(device_info);
671
672 printk(KERN_INFO "dmabounce: device %s on %s bus unregistered\n",
673 dev->bus_id, dev->bus->name);
674 }
675
676
677 EXPORT_SYMBOL(dma_map_single);
678 EXPORT_SYMBOL(dma_unmap_single);
679 EXPORT_SYMBOL(dma_map_sg);
680 EXPORT_SYMBOL(dma_unmap_sg);
681 EXPORT_SYMBOL(dma_sync_single);
682 EXPORT_SYMBOL(dma_sync_sg);
683 EXPORT_SYMBOL(dmabounce_register_dev);
684 EXPORT_SYMBOL(dmabounce_unregister_dev);
685
686 MODULE_AUTHOR("Christopher Hoover <ch@hpl.hp.com>, Deepak Saxena <dsaxena@plexity.net>");
687 MODULE_DESCRIPTION("Special dma_{map/unmap/dma_sync}_* routines for systems with limited DMA windows");
688 MODULE_LICENSE("GPL");
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