Merge tag 'r8169-20060920-00' of git://electric-eye.fr.zoreil.com/home/romieu/linux...
[pandora-kernel.git] / 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         }
285
286         consistent_sync(ptr, size, dir);
287
288         return dma_addr;
289 }
290
291 static inline void
292 unmap_single(struct device *dev, dma_addr_t dma_addr, size_t size,
293                 enum dma_data_direction dir)
294 {
295         struct dmabounce_device_info *device_info = find_dmabounce_dev(dev);
296         struct safe_buffer *buf = NULL;
297
298         /*
299          * Trying to unmap an invalid mapping
300          */
301         if (dma_mapping_error(dma_addr)) {
302                 dev_err(dev, "Trying to unmap invalid mapping\n");
303                 return;
304         }
305
306         if (device_info)
307                 buf = find_safe_buffer(device_info, dma_addr);
308
309         if (buf) {
310                 BUG_ON(buf->size != size);
311
312                 dev_dbg(dev,
313                         "%s: unsafe buffer %p (phy=%p) mapped to %p (phy=%p)\n",
314                         __func__, buf->ptr, (void *) virt_to_dma(dev, buf->ptr),
315                         buf->safe, (void *) buf->safe_dma_addr);
316
317                 DO_STATS ( device_info->bounce_count++ );
318
319                 if (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL) {
320                         unsigned long ptr;
321
322                         dev_dbg(dev,
323                                 "%s: copy back safe %p to unsafe %p size %d\n",
324                                 __func__, buf->safe, buf->ptr, size);
325                         memcpy(buf->ptr, buf->safe, size);
326
327                         /*
328                          * DMA buffers must have the same cache properties
329                          * as if they were really used for DMA - which means
330                          * data must be written back to RAM.  Note that
331                          * we don't use dmac_flush_range() here for the
332                          * bidirectional case because we know the cache
333                          * lines will be coherent with the data written.
334                          */
335                         ptr = (unsigned long)buf->ptr;
336                         dmac_clean_range(ptr, ptr + size);
337                 }
338                 free_safe_buffer(device_info, buf);
339         }
340 }
341
342 static inline void
343 sync_single(struct device *dev, dma_addr_t dma_addr, size_t size,
344                 enum dma_data_direction dir)
345 {
346         struct dmabounce_device_info *device_info = find_dmabounce_dev(dev);
347         struct safe_buffer *buf = NULL;
348
349         if (device_info)
350                 buf = find_safe_buffer(device_info, dma_addr);
351
352         if (buf) {
353                 /*
354                  * Both of these checks from original code need to be
355                  * commented out b/c some drivers rely on the following:
356                  *
357                  * 1) Drivers may map a large chunk of memory into DMA space
358                  *    but only sync a small portion of it. Good example is
359                  *    allocating a large buffer, mapping it, and then
360                  *    breaking it up into small descriptors. No point
361                  *    in syncing the whole buffer if you only have to
362                  *    touch one descriptor.
363                  *
364                  * 2) Buffers that are mapped as DMA_BIDIRECTIONAL are
365                  *    usually only synced in one dir at a time.
366                  *
367                  * See drivers/net/eepro100.c for examples of both cases.
368                  *
369                  * -ds
370                  *
371                  * BUG_ON(buf->size != size);
372                  * BUG_ON(buf->direction != dir);
373                  */
374
375                 dev_dbg(dev,
376                         "%s: unsafe buffer %p (phy=%p) mapped to %p (phy=%p)\n",
377                         __func__, buf->ptr, (void *) virt_to_dma(dev, buf->ptr),
378                         buf->safe, (void *) buf->safe_dma_addr);
379
380                 DO_STATS ( device_info->bounce_count++ );
381
382                 switch (dir) {
383                 case DMA_FROM_DEVICE:
384                         dev_dbg(dev,
385                                 "%s: copy back safe %p to unsafe %p size %d\n",
386                                 __func__, buf->safe, buf->ptr, size);
387                         memcpy(buf->ptr, buf->safe, size);
388                         break;
389                 case DMA_TO_DEVICE:
390                         dev_dbg(dev,
391                                 "%s: copy out unsafe %p to safe %p, size %d\n",
392                                 __func__,buf->ptr, buf->safe, size);
393                         memcpy(buf->safe, buf->ptr, size);
394                         break;
395                 case DMA_BIDIRECTIONAL:
396                         BUG();  /* is this allowed?  what does it mean? */
397                 default:
398                         BUG();
399                 }
400                 consistent_sync(buf->safe, size, dir);
401         } else {
402                 consistent_sync(dma_to_virt(dev, dma_addr), size, dir);
403         }
404 }
405
406 /* ************************************************** */
407
408 /*
409  * see if a buffer address is in an 'unsafe' range.  if it is
410  * allocate a 'safe' buffer and copy the unsafe buffer into it.
411  * substitute the safe buffer for the unsafe one.
412  * (basically move the buffer from an unsafe area to a safe one)
413  */
414 dma_addr_t
415 dma_map_single(struct device *dev, void *ptr, size_t size,
416                 enum dma_data_direction dir)
417 {
418         dma_addr_t dma_addr;
419
420         dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n",
421                 __func__, ptr, size, dir);
422
423         BUG_ON(dir == DMA_NONE);
424
425         dma_addr = map_single(dev, ptr, size, dir);
426
427         return dma_addr;
428 }
429
430 /*
431  * see if a mapped address was really a "safe" buffer and if so, copy
432  * the data from the safe buffer back to the unsafe buffer and free up
433  * the safe buffer.  (basically return things back to the way they
434  * should be)
435  */
436
437 void
438 dma_unmap_single(struct device *dev, dma_addr_t dma_addr, size_t size,
439                         enum dma_data_direction dir)
440 {
441         dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n",
442                 __func__, (void *) dma_addr, size, dir);
443
444         BUG_ON(dir == DMA_NONE);
445
446         unmap_single(dev, dma_addr, size, dir);
447 }
448
449 int
450 dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
451                 enum dma_data_direction dir)
452 {
453         int i;
454
455         dev_dbg(dev, "%s(sg=%p,nents=%d,dir=%x)\n",
456                 __func__, sg, nents, dir);
457
458         BUG_ON(dir == DMA_NONE);
459
460         for (i = 0; i < nents; i++, sg++) {
461                 struct page *page = sg->page;
462                 unsigned int offset = sg->offset;
463                 unsigned int length = sg->length;
464                 void *ptr = page_address(page) + offset;
465
466                 sg->dma_address =
467                         map_single(dev, ptr, length, dir);
468         }
469
470         return nents;
471 }
472
473 void
474 dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,
475                 enum dma_data_direction dir)
476 {
477         int i;
478
479         dev_dbg(dev, "%s(sg=%p,nents=%d,dir=%x)\n",
480                 __func__, sg, nents, dir);
481
482         BUG_ON(dir == DMA_NONE);
483
484         for (i = 0; i < nents; i++, sg++) {
485                 dma_addr_t dma_addr = sg->dma_address;
486                 unsigned int length = sg->length;
487
488                 unmap_single(dev, dma_addr, length, dir);
489         }
490 }
491
492 void
493 dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_addr, size_t size,
494                                 enum dma_data_direction dir)
495 {
496         dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n",
497                 __func__, (void *) dma_addr, size, dir);
498
499         sync_single(dev, dma_addr, size, dir);
500 }
501
502 void
503 dma_sync_single_for_device(struct device *dev, dma_addr_t dma_addr, size_t size,
504                                 enum dma_data_direction dir)
505 {
506         dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n",
507                 __func__, (void *) dma_addr, size, dir);
508
509         sync_single(dev, dma_addr, size, dir);
510 }
511
512 void
513 dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg, int nents,
514                         enum dma_data_direction dir)
515 {
516         int i;
517
518         dev_dbg(dev, "%s(sg=%p,nents=%d,dir=%x)\n",
519                 __func__, sg, nents, dir);
520
521         BUG_ON(dir == DMA_NONE);
522
523         for (i = 0; i < nents; i++, sg++) {
524                 dma_addr_t dma_addr = sg->dma_address;
525                 unsigned int length = sg->length;
526
527                 sync_single(dev, dma_addr, length, dir);
528         }
529 }
530
531 void
532 dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg, int nents,
533                         enum dma_data_direction dir)
534 {
535         int i;
536
537         dev_dbg(dev, "%s(sg=%p,nents=%d,dir=%x)\n",
538                 __func__, sg, nents, dir);
539
540         BUG_ON(dir == DMA_NONE);
541
542         for (i = 0; i < nents; i++, sg++) {
543                 dma_addr_t dma_addr = sg->dma_address;
544                 unsigned int length = sg->length;
545
546                 sync_single(dev, dma_addr, length, dir);
547         }
548 }
549
550 static int
551 dmabounce_init_pool(struct dmabounce_pool *pool, struct device *dev, const char *name,
552                     unsigned long size)
553 {
554         pool->size = size;
555         DO_STATS(pool->allocs = 0);
556         pool->pool = dma_pool_create(name, dev, size,
557                                      0 /* byte alignment */,
558                                      0 /* no page-crossing issues */);
559
560         return pool->pool ? 0 : -ENOMEM;
561 }
562
563 int
564 dmabounce_register_dev(struct device *dev, unsigned long small_buffer_size,
565                         unsigned long large_buffer_size)
566 {
567         struct dmabounce_device_info *device_info;
568         int ret;
569
570         device_info = kmalloc(sizeof(struct dmabounce_device_info), GFP_ATOMIC);
571         if (!device_info) {
572                 printk(KERN_ERR
573                         "Could not allocated dmabounce_device_info for %s",
574                         dev->bus_id);
575                 return -ENOMEM;
576         }
577
578         ret = dmabounce_init_pool(&device_info->small, dev,
579                                   "small_dmabounce_pool", small_buffer_size);
580         if (ret) {
581                 dev_err(dev,
582                         "dmabounce: could not allocate DMA pool for %ld byte objects\n",
583                         small_buffer_size);
584                 goto err_free;
585         }
586
587         if (large_buffer_size) {
588                 ret = dmabounce_init_pool(&device_info->large, dev,
589                                           "large_dmabounce_pool",
590                                           large_buffer_size);
591                 if (ret) {
592                         dev_err(dev,
593                                 "dmabounce: could not allocate DMA pool for %ld byte objects\n",
594                                 large_buffer_size);
595                         goto err_destroy;
596                 }
597         }
598
599         device_info->dev = dev;
600         INIT_LIST_HEAD(&device_info->safe_buffers);
601         rwlock_init(&device_info->lock);
602
603 #ifdef STATS
604         device_info->total_allocs = 0;
605         device_info->map_op_count = 0;
606         device_info->bounce_count = 0;
607 #endif
608
609         list_add(&device_info->node, &dmabounce_devs);
610
611         printk(KERN_INFO "dmabounce: registered device %s on %s bus\n",
612                 dev->bus_id, dev->bus->name);
613
614         return 0;
615
616  err_destroy:
617         dma_pool_destroy(device_info->small.pool);
618  err_free:
619         kfree(device_info);
620         return ret;
621 }
622
623 void
624 dmabounce_unregister_dev(struct device *dev)
625 {
626         struct dmabounce_device_info *device_info = find_dmabounce_dev(dev);
627
628         if (!device_info) {
629                 printk(KERN_WARNING
630                         "%s: Never registered with dmabounce but attempting" \
631                         "to unregister!\n", dev->bus_id);
632                 return;
633         }
634
635         if (!list_empty(&device_info->safe_buffers)) {
636                 printk(KERN_ERR
637                         "%s: Removing from dmabounce with pending buffers!\n",
638                         dev->bus_id);
639                 BUG();
640         }
641
642         if (device_info->small.pool)
643                 dma_pool_destroy(device_info->small.pool);
644         if (device_info->large.pool)
645                 dma_pool_destroy(device_info->large.pool);
646
647 #ifdef STATS
648         print_alloc_stats(device_info);
649         print_map_stats(device_info);
650 #endif
651
652         list_del(&device_info->node);
653
654         kfree(device_info);
655
656         printk(KERN_INFO "dmabounce: device %s on %s bus unregistered\n",
657                 dev->bus_id, dev->bus->name);
658 }
659
660
661 EXPORT_SYMBOL(dma_map_single);
662 EXPORT_SYMBOL(dma_unmap_single);
663 EXPORT_SYMBOL(dma_map_sg);
664 EXPORT_SYMBOL(dma_unmap_sg);
665 EXPORT_SYMBOL(dma_sync_single);
666 EXPORT_SYMBOL(dma_sync_sg);
667 EXPORT_SYMBOL(dmabounce_register_dev);
668 EXPORT_SYMBOL(dmabounce_unregister_dev);
669
670 MODULE_AUTHOR("Christopher Hoover <ch@hpl.hp.com>, Deepak Saxena <dsaxena@plexity.net>");
671 MODULE_DESCRIPTION("Special dma_{map/unmap/dma_sync}_* routines for systems with limited DMA windows");
672 MODULE_LICENSE("GPL");