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