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x86: cpa self-test, WARN_ON()
[wrt350n-kernel.git] / arch / arm / common / dmabounce.c
blob52fc6a883281120f7c80e2d332247971658b1ffa
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, the remainder of memory is at the top and the DMA memory
9 * can be marked as ZONE_DMA. Anything beyond that such as discontiguous
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 #include <linux/scatterlist.h>
33
34 #include <asm/cacheflush.h>
35
36 #undef STATS
37
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 dmabounce_pool *pool;
56 void *safe;
57 dma_addr_t safe_dma_addr;
58 };
59
60 struct dmabounce_pool {
61 unsigned long size;
62 struct dma_pool *pool;
63 #ifdef STATS
64 unsigned long allocs;
65 #endif
66 };
67
68 struct dmabounce_device_info {
69 struct device *dev;
70 struct list_head safe_buffers;
71 #ifdef STATS
72 unsigned long total_allocs;
73 unsigned long map_op_count;
74 unsigned long bounce_count;
75 int attr_res;
76 #endif
77 struct dmabounce_pool small;
78 struct dmabounce_pool large;
79
80 rwlock_t lock;
81 };
82
83 #ifdef STATS
84 static ssize_t dmabounce_show(struct device *dev, struct device_attribute *attr,
85 char *buf)
86 {
87 struct dmabounce_device_info *device_info = dev->archdata.dmabounce;
88 return sprintf(buf, "%lu %lu %lu %lu %lu %lu\n",
89 device_info->small.allocs,
90 device_info->large.allocs,
91 device_info->total_allocs - device_info->small.allocs -
92 device_info->large.allocs,
93 device_info->total_allocs,
94 device_info->map_op_count,
95 device_info->bounce_count);
96 }
97
98 static DEVICE_ATTR(dmabounce_stats, 0400, dmabounce_show, NULL);
99 #endif
100
101
102 /* allocate a 'safe' buffer and keep track of it */
103 static inline struct safe_buffer *
104 alloc_safe_buffer(struct dmabounce_device_info *device_info, void *ptr,
105 size_t size, enum dma_data_direction dir)
106 {
107 struct safe_buffer *buf;
108 struct dmabounce_pool *pool;
109 struct device *dev = device_info->dev;
110 unsigned long flags;
111
112 dev_dbg(dev, "%s(ptr=%p, size=%d, dir=%d)\n",
113 __func__, ptr, size, dir);
114
115 if (size <= device_info->small.size) {
116 pool = &device_info->small;
117 } else if (size <= device_info->large.size) {
118 pool = &device_info->large;
119 } else {
120 pool = NULL;
121 }
122
123 buf = kmalloc(sizeof(struct safe_buffer), GFP_ATOMIC);
124 if (buf == NULL) {
125 dev_warn(dev, "%s: kmalloc failed\n", __func__);
126 return NULL;
127 }
128
129 buf->ptr = ptr;
130 buf->size = size;
131 buf->direction = dir;
132 buf->pool = pool;
133
134 if (pool) {
135 buf->safe = dma_pool_alloc(pool->pool, GFP_ATOMIC,
136 &buf->safe_dma_addr);
137 } else {
138 buf->safe = dma_alloc_coherent(dev, size, &buf->safe_dma_addr,
139 GFP_ATOMIC);
140 }
141
142 if (buf->safe == NULL) {
143 dev_warn(dev,
144 "%s: could not alloc dma memory (size=%d)\n",
145 __func__, size);
146 kfree(buf);
147 return NULL;
148 }
149
150 #ifdef STATS
151 if (pool)
152 pool->allocs++;
153 device_info->total_allocs++;
154 #endif
155
156 write_lock_irqsave(&device_info->lock, flags);
157
158 list_add(&buf->node, &device_info->safe_buffers);
159
160 write_unlock_irqrestore(&device_info->lock, flags);
161
162 return buf;
163 }
164
165 /* determine if a buffer is from our "safe" pool */
166 static inline struct safe_buffer *
167 find_safe_buffer(struct dmabounce_device_info *device_info, dma_addr_t safe_dma_addr)
168 {
169 struct safe_buffer *b, *rb = NULL;
170 unsigned long flags;
171
172 read_lock_irqsave(&device_info->lock, flags);
173
174 list_for_each_entry(b, &device_info->safe_buffers, node)
175 if (b->safe_dma_addr == safe_dma_addr) {
176 rb = b;
177 break;
178 }
179
180 read_unlock_irqrestore(&device_info->lock, flags);
181 return rb;
182 }
183
184 static inline void
185 free_safe_buffer(struct dmabounce_device_info *device_info, struct safe_buffer *buf)
186 {
187 unsigned long flags;
188
189 dev_dbg(device_info->dev, "%s(buf=%p)\n", __func__, buf);
190
191 write_lock_irqsave(&device_info->lock, flags);
192
193 list_del(&buf->node);
194
195 write_unlock_irqrestore(&device_info->lock, flags);
196
197 if (buf->pool)
198 dma_pool_free(buf->pool->pool, buf->safe, buf->safe_dma_addr);
199 else
200 dma_free_coherent(device_info->dev, buf->size, buf->safe,
201 buf->safe_dma_addr);
202
203 kfree(buf);
204 }
205
206 /* ************************************************** */
207
208 static inline dma_addr_t
209 map_single(struct device *dev, void *ptr, size_t size,
210 enum dma_data_direction dir)
211 {
212 struct dmabounce_device_info *device_info = dev->archdata.dmabounce;
213 dma_addr_t dma_addr;
214 int needs_bounce = 0;
215
216 if (device_info)
217 DO_STATS ( device_info->map_op_count++ );
218
219 dma_addr = virt_to_dma(dev, ptr);
220
221 if (dev->dma_mask) {
222 unsigned long mask = *dev->dma_mask;
223 unsigned long limit;
224
225 limit = (mask + 1) & ~mask;
226 if (limit && size > limit) {
227 dev_err(dev, "DMA mapping too big (requested %#x "
228 "mask %#Lx)\n", size, *dev->dma_mask);
229 return ~0;
230 }
231
232 /*
233 * Figure out if we need to bounce from the DMA mask.
234 */
235 needs_bounce = (dma_addr | (dma_addr + size - 1)) & ~mask;
236 }
237
238 if (device_info && (needs_bounce || dma_needs_bounce(dev, dma_addr, size))) {
239 struct safe_buffer *buf;
240
241 buf = alloc_safe_buffer(device_info, ptr, size, dir);
242 if (buf == 0) {
243 dev_err(dev, "%s: unable to map unsafe buffer %p!\n",
244 __func__, ptr);
245 return 0;
246 }
247
248 dev_dbg(dev,
249 "%s: unsafe buffer %p (phy=%p) mapped to %p (phy=%p)\n",
250 __func__, buf->ptr, (void *) virt_to_dma(dev, buf->ptr),
251 buf->safe, (void *) buf->safe_dma_addr);
252
253 if ((dir == DMA_TO_DEVICE) ||
254 (dir == DMA_BIDIRECTIONAL)) {
255 dev_dbg(dev, "%s: copy unsafe %p to safe %p, size %d\n",
256 __func__, ptr, buf->safe, size);
257 memcpy(buf->safe, ptr, size);
258 }
259 ptr = buf->safe;
260
261 dma_addr = buf->safe_dma_addr;
262 } else {
263 /*
264 * We don't need to sync the DMA buffer since
265 * it was allocated via the coherent allocators.
266 */
267 dma_cache_maint(ptr, size, dir);
268 }
269
270 return dma_addr;
271 }
272
273 static inline void
274 unmap_single(struct device *dev, dma_addr_t dma_addr, size_t size,
275 enum dma_data_direction dir)
276 {
277 struct dmabounce_device_info *device_info = dev->archdata.dmabounce;
278 struct safe_buffer *buf = NULL;
279
280 /*
281 * Trying to unmap an invalid mapping
282 */
283 if (dma_mapping_error(dma_addr)) {
284 dev_err(dev, "Trying to unmap invalid mapping\n");
285 return;
286 }
287
288 if (device_info)
289 buf = find_safe_buffer(device_info, dma_addr);
290
291 if (buf) {
292 BUG_ON(buf->size != size);
293
294 dev_dbg(dev,
295 "%s: unsafe buffer %p (phy=%p) mapped to %p (phy=%p)\n",
296 __func__, buf->ptr, (void *) virt_to_dma(dev, buf->ptr),
297 buf->safe, (void *) buf->safe_dma_addr);
298
299 DO_STATS ( device_info->bounce_count++ );
300
301 if (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL) {
302 void *ptr = buf->ptr;
303
304 dev_dbg(dev,
305 "%s: copy back safe %p to unsafe %p size %d\n",
306 __func__, buf->safe, ptr, size);
307 memcpy(ptr, buf->safe, size);
308
309 /*
310 * DMA buffers must have the same cache properties
311 * as if they were really used for DMA - which means
312 * data must be written back to RAM. Note that
313 * we don't use dmac_flush_range() here for the
314 * bidirectional case because we know the cache
315 * lines will be coherent with the data written.
316 */
317 dmac_clean_range(ptr, ptr + size);
318 outer_clean_range(__pa(ptr), __pa(ptr) + size);
319 }
320 free_safe_buffer(device_info, buf);
321 }
322 }
323
324 static inline void
325 sync_single(struct device *dev, dma_addr_t dma_addr, size_t size,
326 enum dma_data_direction dir)
327 {
328 struct dmabounce_device_info *device_info = dev->archdata.dmabounce;
329 struct safe_buffer *buf = NULL;
330
331 if (device_info)
332 buf = find_safe_buffer(device_info, dma_addr);
333
334 if (buf) {
335 /*
336 * Both of these checks from original code need to be
337 * commented out b/c some drivers rely on the following:
338 *
339 * 1) Drivers may map a large chunk of memory into DMA space
340 * but only sync a small portion of it. Good example is
341 * allocating a large buffer, mapping it, and then
342 * breaking it up into small descriptors. No point
343 * in syncing the whole buffer if you only have to
344 * touch one descriptor.
345 *
346 * 2) Buffers that are mapped as DMA_BIDIRECTIONAL are
347 * usually only synced in one dir at a time.
348 *
349 * See drivers/net/eepro100.c for examples of both cases.
350 *
351 * -ds
352 *
353 * BUG_ON(buf->size != size);
354 * BUG_ON(buf->direction != dir);
355 */
356
357 dev_dbg(dev,
358 "%s: unsafe buffer %p (phy=%p) mapped to %p (phy=%p)\n",
359 __func__, buf->ptr, (void *) virt_to_dma(dev, buf->ptr),
360 buf->safe, (void *) buf->safe_dma_addr);
361
362 DO_STATS ( device_info->bounce_count++ );
363
364 switch (dir) {
365 case DMA_FROM_DEVICE:
366 dev_dbg(dev,
367 "%s: copy back safe %p to unsafe %p size %d\n",
368 __func__, buf->safe, buf->ptr, size);
369 memcpy(buf->ptr, buf->safe, size);
370 break;
371 case DMA_TO_DEVICE:
372 dev_dbg(dev,
373 "%s: copy out unsafe %p to safe %p, size %d\n",
374 __func__,buf->ptr, buf->safe, size);
375 memcpy(buf->safe, buf->ptr, size);
376 break;
377 case DMA_BIDIRECTIONAL:
378 BUG(); /* is this allowed? what does it mean? */
379 default:
380 BUG();
381 }
382 /*
383 * No need to sync the safe buffer - it was allocated
384 * via the coherent allocators.
385 */
386 } else {
387 dma_cache_maint(dma_to_virt(dev, dma_addr), size, dir);
388 }
389 }
390
391 /* ************************************************** */
392
393 /*
394 * see if a buffer address is in an 'unsafe' range. if it is
395 * allocate a 'safe' buffer and copy the unsafe buffer into it.
396 * substitute the safe buffer for the unsafe one.
397 * (basically move the buffer from an unsafe area to a safe one)
398 */
399 dma_addr_t
400 dma_map_single(struct device *dev, void *ptr, size_t size,
401 enum dma_data_direction dir)
402 {
403 dma_addr_t dma_addr;
404
405 dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n",
406 __func__, ptr, size, dir);
407
408 BUG_ON(dir == DMA_NONE);
409
410 dma_addr = map_single(dev, ptr, size, dir);
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 dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n",
427 __func__, (void *) dma_addr, size, dir);
428
429 BUG_ON(dir == DMA_NONE);
430
431 unmap_single(dev, dma_addr, size, dir);
432 }
433
434 int
435 dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
436 enum dma_data_direction dir)
437 {
438 int i;
439
440 dev_dbg(dev, "%s(sg=%p,nents=%d,dir=%x)\n",
441 __func__, sg, nents, dir);
442
443 BUG_ON(dir == DMA_NONE);
444
445 for (i = 0; i < nents; i++, sg++) {
446 struct page *page = sg_page(sg);
447 unsigned int offset = sg->offset;
448 unsigned int length = sg->length;
449 void *ptr = page_address(page) + offset;
450
451 sg->dma_address =
452 map_single(dev, ptr, length, dir);
453 }
454
455 return nents;
456 }
457
458 void
459 dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,
460 enum dma_data_direction dir)
461 {
462 int i;
463
464 dev_dbg(dev, "%s(sg=%p,nents=%d,dir=%x)\n",
465 __func__, sg, nents, dir);
466
467 BUG_ON(dir == DMA_NONE);
468
469 for (i = 0; i < nents; i++, sg++) {
470 dma_addr_t dma_addr = sg->dma_address;
471 unsigned int length = sg->length;
472
473 unmap_single(dev, dma_addr, length, dir);
474 }
475 }
476
477 void
478 dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_addr, size_t size,
479 enum dma_data_direction dir)
480 {
481 dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n",
482 __func__, (void *) dma_addr, size, dir);
483
484 sync_single(dev, dma_addr, size, dir);
485 }
486
487 void
488 dma_sync_single_for_device(struct device *dev, dma_addr_t dma_addr, size_t size,
489 enum dma_data_direction dir)
490 {
491 dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n",
492 __func__, (void *) dma_addr, size, dir);
493
494 sync_single(dev, dma_addr, size, dir);
495 }
496
497 void
498 dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg, int nents,
499 enum dma_data_direction dir)
500 {
501 int i;
502
503 dev_dbg(dev, "%s(sg=%p,nents=%d,dir=%x)\n",
504 __func__, sg, nents, dir);
505
506 BUG_ON(dir == DMA_NONE);
507
508 for (i = 0; i < nents; i++, sg++) {
509 dma_addr_t dma_addr = sg->dma_address;
510 unsigned int length = sg->length;
511
512 sync_single(dev, dma_addr, length, dir);
513 }
514 }
515
516 void
517 dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg, int nents,
518 enum dma_data_direction dir)
519 {
520 int i;
521
522 dev_dbg(dev, "%s(sg=%p,nents=%d,dir=%x)\n",
523 __func__, sg, nents, dir);
524
525 BUG_ON(dir == DMA_NONE);
526
527 for (i = 0; i < nents; i++, sg++) {
528 dma_addr_t dma_addr = sg->dma_address;
529 unsigned int length = sg->length;
530
531 sync_single(dev, dma_addr, length, dir);
532 }
533 }
534
535 static int
536 dmabounce_init_pool(struct dmabounce_pool *pool, struct device *dev, const char *name,
537 unsigned long size)
538 {
539 pool->size = size;
540 DO_STATS(pool->allocs = 0);
541 pool->pool = dma_pool_create(name, dev, size,
542 0 /* byte alignment */,
543 0 /* no page-crossing issues */);
544
545 return pool->pool ? 0 : -ENOMEM;
546 }
547
548 int
549 dmabounce_register_dev(struct device *dev, unsigned long small_buffer_size,
550 unsigned long large_buffer_size)
551 {
552 struct dmabounce_device_info *device_info;
553 int ret;
554
555 device_info = kmalloc(sizeof(struct dmabounce_device_info), GFP_ATOMIC);
556 if (!device_info) {
557 printk(KERN_ERR
558 "Could not allocated dmabounce_device_info for %s",
559 dev->bus_id);
560 return -ENOMEM;
561 }
562
563 ret = dmabounce_init_pool(&device_info->small, dev,
564 "small_dmabounce_pool", small_buffer_size);
565 if (ret) {
566 dev_err(dev,
567 "dmabounce: could not allocate DMA pool for %ld byte objects\n",
568 small_buffer_size);
569 goto err_free;
570 }
571
572 if (large_buffer_size) {
573 ret = dmabounce_init_pool(&device_info->large, dev,
574 "large_dmabounce_pool",
575 large_buffer_size);
576 if (ret) {
577 dev_err(dev,
578 "dmabounce: could not allocate DMA pool for %ld byte objects\n",
579 large_buffer_size);
580 goto err_destroy;
581 }
582 }
583
584 device_info->dev = dev;
585 INIT_LIST_HEAD(&device_info->safe_buffers);
586 rwlock_init(&device_info->lock);
587
588 #ifdef STATS
589 device_info->total_allocs = 0;
590 device_info->map_op_count = 0;
591 device_info->bounce_count = 0;
592 device_info->attr_res = device_create_file(dev, &dev_attr_dmabounce_stats);
593 #endif
594
595 dev->archdata.dmabounce = device_info;
596
597 printk(KERN_INFO "dmabounce: registered device %s on %s bus\n",
598 dev->bus_id, dev->bus->name);
599
600 return 0;
601
602 err_destroy:
603 dma_pool_destroy(device_info->small.pool);
604 err_free:
605 kfree(device_info);
606 return ret;
607 }
608
609 void
610 dmabounce_unregister_dev(struct device *dev)
611 {
612 struct dmabounce_device_info *device_info = dev->archdata.dmabounce;
613
614 dev->archdata.dmabounce = NULL;
615
616 if (!device_info) {
617 printk(KERN_WARNING
618 "%s: Never registered with dmabounce but attempting" \
619 "to unregister!\n", dev->bus_id);
620 return;
621 }
622
623 if (!list_empty(&device_info->safe_buffers)) {
624 printk(KERN_ERR
625 "%s: Removing from dmabounce with pending buffers!\n",
626 dev->bus_id);
627 BUG();
628 }
629
630 if (device_info->small.pool)
631 dma_pool_destroy(device_info->small.pool);
632 if (device_info->large.pool)
633 dma_pool_destroy(device_info->large.pool);
634
635 #ifdef STATS
636 if (device_info->attr_res == 0)
637 device_remove_file(dev, &dev_attr_dmabounce_stats);
638 #endif
639
640 kfree(device_info);
641
642 printk(KERN_INFO "dmabounce: device %s on %s bus unregistered\n",
643 dev->bus_id, dev->bus->name);
644 }
645
646
647 EXPORT_SYMBOL(dma_map_single);
648 EXPORT_SYMBOL(dma_unmap_single);
649 EXPORT_SYMBOL(dma_map_sg);
650 EXPORT_SYMBOL(dma_unmap_sg);
651 EXPORT_SYMBOL(dma_sync_single_for_cpu);
652 EXPORT_SYMBOL(dma_sync_single_for_device);
653 EXPORT_SYMBOL(dma_sync_sg);
654 EXPORT_SYMBOL(dmabounce_register_dev);
655 EXPORT_SYMBOL(dmabounce_unregister_dev);
656
657 MODULE_AUTHOR("Christopher Hoover <ch@hpl.hp.com>, Deepak Saxena <dsaxena@plexity.net>");
658 MODULE_DESCRIPTION("Special dma_{map/unmap/dma_sync}_* routines for systems with limited DMA windows");
659 MODULE_LICENSE("GPL");
WRT350N Kernel Patches