Merge git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc
[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
82 static LIST_HEAD(dmabounce_devs);
83
84 #ifdef STATS
85 static void print_alloc_stats(struct dmabounce_device_info *device_info)
86 {
87         printk(KERN_INFO
88                 "%s: dmabounce: sbp: %lu, lbp: %lu, other: %lu, total: %lu\n",
89                 device_info->dev->bus_id,
90                 device_info->small.allocs, device_info->large.allocs,
91                 device_info->total_allocs - device_info->small.allocs -
92                         device_info->large.allocs,
93                 device_info->total_allocs);
94 }
95 #endif
96
97 /* find the given device in the dmabounce device list */
98 static inline struct dmabounce_device_info *
99 find_dmabounce_dev(struct device *dev)
100 {
101         struct dmabounce_device_info *d;
102
103         list_for_each_entry(d, &dmabounce_devs, node)
104                 if (d->dev == dev)
105                         return d;
106
107         return NULL;
108 }
109
110
111 /* allocate a 'safe' buffer and keep track of it */
112 static inline struct safe_buffer *
113 alloc_safe_buffer(struct dmabounce_device_info *device_info, void *ptr,
114                   size_t size, enum dma_data_direction dir)
115 {
116         struct safe_buffer *buf;
117         struct dmabounce_pool *pool;
118         struct device *dev = device_info->dev;
119
120         dev_dbg(dev, "%s(ptr=%p, size=%d, dir=%d)\n",
121                 __func__, ptr, size, dir);
122
123         if (size <= device_info->small.size) {
124                 pool = &device_info->small;
125         } else if (size <= device_info->large.size) {
126                 pool = &device_info->large;
127         } else {
128                 pool = NULL;
129         }
130
131         buf = kmalloc(sizeof(struct safe_buffer), GFP_ATOMIC);
132         if (buf == NULL) {
133                 dev_warn(dev, "%s: kmalloc failed\n", __func__);
134                 return NULL;
135         }
136
137         buf->ptr = ptr;
138         buf->size = size;
139         buf->direction = dir;
140         buf->pool = pool;
141
142         if (pool) {
143                 buf->safe = dma_pool_alloc(pool->pool, GFP_ATOMIC,
144                                            &buf->safe_dma_addr);
145         } else {
146                 buf->safe = dma_alloc_coherent(dev, size, &buf->safe_dma_addr,
147                                                GFP_ATOMIC);
148         }
149
150         if (buf->safe == NULL) {
151                 dev_warn(dev,
152                          "%s: could not alloc dma memory (size=%d)\n",
153                          __func__, size);
154                 kfree(buf);
155                 return NULL;
156         }
157
158 #ifdef STATS
159         if (pool)
160                 pool->allocs++;
161         device_info->total_allocs++;
162         if (device_info->total_allocs % 1000 == 0)
163                 print_alloc_stats(device_info);
164 #endif
165
166         list_add(&buf->node, &device_info->safe_buffers);
167
168         return buf;
169 }
170
171 /* determine if a buffer is from our "safe" pool */
172 static inline struct safe_buffer *
173 find_safe_buffer(struct dmabounce_device_info *device_info, dma_addr_t safe_dma_addr)
174 {
175         struct safe_buffer *b;
176
177         list_for_each_entry(b, &device_info->safe_buffers, node)
178                 if (b->safe_dma_addr == safe_dma_addr)
179                         return b;
180
181         return NULL;
182 }
183
184 static inline void
185 free_safe_buffer(struct dmabounce_device_info *device_info, struct safe_buffer *buf)
186 {
187         dev_dbg(device_info->dev, "%s(buf=%p)\n", __func__, buf);
188
189         list_del(&buf->node);
190
191         if (buf->pool)
192                 dma_pool_free(buf->pool->pool, buf->safe, buf->safe_dma_addr);
193         else
194                 dma_free_coherent(device_info->dev, buf->size, buf->safe,
195                                     buf->safe_dma_addr);
196
197         kfree(buf);
198 }
199
200 /* ************************************************** */
201
202 #ifdef STATS
203 static void print_map_stats(struct dmabounce_device_info *device_info)
204 {
205         dev_info(device_info->dev,
206                 "dmabounce: map_op_count=%lu, bounce_count=%lu\n",
207                 device_info->map_op_count, device_info->bounce_count);
208 }
209 #endif
210
211 static inline dma_addr_t
212 map_single(struct device *dev, void *ptr, size_t size,
213                 enum dma_data_direction dir)
214 {
215         struct dmabounce_device_info *device_info = find_dmabounce_dev(dev);
216         dma_addr_t dma_addr;
217         int needs_bounce = 0;
218
219         if (device_info)
220                 DO_STATS ( device_info->map_op_count++ );
221
222         dma_addr = virt_to_dma(dev, ptr);
223
224         if (dev->dma_mask) {
225                 unsigned long mask = *dev->dma_mask;
226                 unsigned long limit;
227
228                 limit = (mask + 1) & ~mask;
229                 if (limit && size > limit) {
230                         dev_err(dev, "DMA mapping too big (requested %#x "
231                                 "mask %#Lx)\n", size, *dev->dma_mask);
232                         return ~0;
233                 }
234
235                 /*
236                  * Figure out if we need to bounce from the DMA mask.
237                  */
238                 needs_bounce = (dma_addr | (dma_addr + size - 1)) & ~mask;
239         }
240
241         if (device_info && (needs_bounce || dma_needs_bounce(dev, dma_addr, size))) {
242                 struct safe_buffer *buf;
243
244                 buf = alloc_safe_buffer(device_info, ptr, size, dir);
245                 if (buf == 0) {
246                         dev_err(dev, "%s: unable to map unsafe buffer %p!\n",
247                                __func__, ptr);
248                         return 0;
249                 }
250
251                 dev_dbg(dev,
252                         "%s: unsafe buffer %p (phy=%p) mapped to %p (phy=%p)\n",
253                         __func__, buf->ptr, (void *) virt_to_dma(dev, buf->ptr),
254                         buf->safe, (void *) buf->safe_dma_addr);
255
256                 if ((dir == DMA_TO_DEVICE) ||
257                     (dir == DMA_BIDIRECTIONAL)) {
258                         dev_dbg(dev, "%s: copy unsafe %p to safe %p, size %d\n",
259                                 __func__, ptr, buf->safe, size);
260                         memcpy(buf->safe, ptr, size);
261                 }
262                 ptr = buf->safe;
263
264                 dma_addr = buf->safe_dma_addr;
265         }
266
267         consistent_sync(ptr, size, dir);
268
269         return dma_addr;
270 }
271
272 static inline void
273 unmap_single(struct device *dev, dma_addr_t dma_addr, size_t size,
274                 enum dma_data_direction dir)
275 {
276         struct dmabounce_device_info *device_info = find_dmabounce_dev(dev);
277         struct safe_buffer *buf = NULL;
278
279         /*
280          * Trying to unmap an invalid mapping
281          */
282         if (dma_mapping_error(dma_addr)) {
283                 dev_err(dev, "Trying to unmap invalid mapping\n");
284                 return;
285         }
286
287         if (device_info)
288                 buf = find_safe_buffer(device_info, dma_addr);
289
290         if (buf) {
291                 BUG_ON(buf->size != size);
292
293                 dev_dbg(dev,
294                         "%s: unsafe buffer %p (phy=%p) mapped to %p (phy=%p)\n",
295                         __func__, buf->ptr, (void *) virt_to_dma(dev, buf->ptr),
296                         buf->safe, (void *) buf->safe_dma_addr);
297
298                 DO_STATS ( device_info->bounce_count++ );
299
300                 if (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL) {
301                         unsigned long ptr;
302
303                         dev_dbg(dev,
304                                 "%s: copy back safe %p to unsafe %p size %d\n",
305                                 __func__, buf->safe, buf->ptr, size);
306                         memcpy(buf->ptr, buf->safe, size);
307
308                         /*
309                          * DMA buffers must have the same cache properties
310                          * as if they were really used for DMA - which means
311                          * data must be written back to RAM.  Note that
312                          * we don't use dmac_flush_range() here for the
313                          * bidirectional case because we know the cache
314                          * lines will be coherent with the data written.
315                          */
316                         ptr = (unsigned long)buf->ptr;
317                         dmac_clean_range(ptr, ptr + size);
318                 }
319                 free_safe_buffer(device_info, buf);
320         }
321 }
322
323 static inline void
324 sync_single(struct device *dev, dma_addr_t dma_addr, size_t size,
325                 enum dma_data_direction dir)
326 {
327         struct dmabounce_device_info *device_info = find_dmabounce_dev(dev);
328         struct safe_buffer *buf = NULL;
329
330         if (device_info)
331                 buf = find_safe_buffer(device_info, dma_addr);
332
333         if (buf) {
334                 /*
335                  * Both of these checks from original code need to be
336                  * commented out b/c some drivers rely on the following:
337                  *
338                  * 1) Drivers may map a large chunk of memory into DMA space
339                  *    but only sync a small portion of it. Good example is
340                  *    allocating a large buffer, mapping it, and then
341                  *    breaking it up into small descriptors. No point
342                  *    in syncing the whole buffer if you only have to
343                  *    touch one descriptor.
344                  *
345                  * 2) Buffers that are mapped as DMA_BIDIRECTIONAL are
346                  *    usually only synced in one dir at a time.
347                  *
348                  * See drivers/net/eepro100.c for examples of both cases.
349                  *
350                  * -ds
351                  *
352                  * BUG_ON(buf->size != size);
353                  * BUG_ON(buf->direction != dir);
354                  */
355
356                 dev_dbg(dev,
357                         "%s: unsafe buffer %p (phy=%p) mapped to %p (phy=%p)\n",
358                         __func__, buf->ptr, (void *) virt_to_dma(dev, buf->ptr),
359                         buf->safe, (void *) buf->safe_dma_addr);
360
361                 DO_STATS ( device_info->bounce_count++ );
362
363                 switch (dir) {
364                 case DMA_FROM_DEVICE:
365                         dev_dbg(dev,
366                                 "%s: copy back safe %p to unsafe %p size %d\n",
367                                 __func__, buf->safe, buf->ptr, size);
368                         memcpy(buf->ptr, buf->safe, size);
369                         break;
370                 case DMA_TO_DEVICE:
371                         dev_dbg(dev,
372                                 "%s: copy out unsafe %p to safe %p, size %d\n",
373                                 __func__,buf->ptr, buf->safe, size);
374                         memcpy(buf->safe, buf->ptr, size);
375                         break;
376                 case DMA_BIDIRECTIONAL:
377                         BUG();  /* is this allowed?  what does it mean? */
378                 default:
379                         BUG();
380                 }
381                 consistent_sync(buf->safe, size, dir);
382         } else {
383                 consistent_sync(dma_to_virt(dev, dma_addr), size, dir);
384         }
385 }
386
387 /* ************************************************** */
388
389 /*
390  * see if a buffer address is in an 'unsafe' range.  if it is
391  * allocate a 'safe' buffer and copy the unsafe buffer into it.
392  * substitute the safe buffer for the unsafe one.
393  * (basically move the buffer from an unsafe area to a safe one)
394  */
395 dma_addr_t
396 dma_map_single(struct device *dev, void *ptr, size_t size,
397                 enum dma_data_direction dir)
398 {
399         unsigned long flags;
400         dma_addr_t dma_addr;
401
402         dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n",
403                 __func__, ptr, size, dir);
404
405         BUG_ON(dir == DMA_NONE);
406
407         local_irq_save(flags);
408
409         dma_addr = map_single(dev, ptr, size, dir);
410
411         local_irq_restore(flags);
412
413         return dma_addr;
414 }
415
416 /*
417  * see if a mapped address was really a "safe" buffer and if so, copy
418  * the data from the safe buffer back to the unsafe buffer and free up
419  * the safe buffer.  (basically return things back to the way they
420  * should be)
421  */
422
423 void
424 dma_unmap_single(struct device *dev, dma_addr_t dma_addr, size_t size,
425                         enum dma_data_direction dir)
426 {
427         unsigned long flags;
428
429         dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n",
430                 __func__, (void *) dma_addr, size, dir);
431
432         BUG_ON(dir == DMA_NONE);
433
434         local_irq_save(flags);
435
436         unmap_single(dev, dma_addr, size, dir);
437
438         local_irq_restore(flags);
439 }
440
441 int
442 dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
443                 enum dma_data_direction dir)
444 {
445         unsigned long flags;
446         int i;
447
448         dev_dbg(dev, "%s(sg=%p,nents=%d,dir=%x)\n",
449                 __func__, sg, nents, dir);
450
451         BUG_ON(dir == DMA_NONE);
452
453         local_irq_save(flags);
454
455         for (i = 0; i < nents; i++, sg++) {
456                 struct page *page = sg->page;
457                 unsigned int offset = sg->offset;
458                 unsigned int length = sg->length;
459                 void *ptr = page_address(page) + offset;
460
461                 sg->dma_address =
462                         map_single(dev, ptr, length, dir);
463         }
464
465         local_irq_restore(flags);
466
467         return nents;
468 }
469
470 void
471 dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,
472                 enum dma_data_direction dir)
473 {
474         unsigned long flags;
475         int i;
476
477         dev_dbg(dev, "%s(sg=%p,nents=%d,dir=%x)\n",
478                 __func__, sg, nents, dir);
479
480         BUG_ON(dir == DMA_NONE);
481
482         local_irq_save(flags);
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         local_irq_restore(flags);
492 }
493
494 void
495 dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_addr, size_t size,
496                                 enum dma_data_direction dir)
497 {
498         unsigned long flags;
499
500         dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n",
501                 __func__, (void *) dma_addr, size, dir);
502
503         local_irq_save(flags);
504
505         sync_single(dev, dma_addr, size, dir);
506
507         local_irq_restore(flags);
508 }
509
510 void
511 dma_sync_single_for_device(struct device *dev, dma_addr_t dma_addr, size_t size,
512                                 enum dma_data_direction dir)
513 {
514         unsigned long flags;
515
516         dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n",
517                 __func__, (void *) dma_addr, size, dir);
518
519         local_irq_save(flags);
520
521         sync_single(dev, dma_addr, size, dir);
522
523         local_irq_restore(flags);
524 }
525
526 void
527 dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg, int nents,
528                         enum dma_data_direction dir)
529 {
530         unsigned long flags;
531         int i;
532
533         dev_dbg(dev, "%s(sg=%p,nents=%d,dir=%x)\n",
534                 __func__, sg, nents, dir);
535
536         BUG_ON(dir == DMA_NONE);
537
538         local_irq_save(flags);
539
540         for (i = 0; i < nents; i++, sg++) {
541                 dma_addr_t dma_addr = sg->dma_address;
542                 unsigned int length = sg->length;
543
544                 sync_single(dev, dma_addr, length, dir);
545         }
546
547         local_irq_restore(flags);
548 }
549
550 void
551 dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg, int nents,
552                         enum dma_data_direction dir)
553 {
554         unsigned long flags;
555         int i;
556
557         dev_dbg(dev, "%s(sg=%p,nents=%d,dir=%x)\n",
558                 __func__, sg, nents, dir);
559
560         BUG_ON(dir == DMA_NONE);
561
562         local_irq_save(flags);
563
564         for (i = 0; i < nents; i++, sg++) {
565                 dma_addr_t dma_addr = sg->dma_address;
566                 unsigned int length = sg->length;
567
568                 sync_single(dev, dma_addr, length, dir);
569         }
570
571         local_irq_restore(flags);
572 }
573
574 static int
575 dmabounce_init_pool(struct dmabounce_pool *pool, struct device *dev, const char *name,
576                     unsigned long size)
577 {
578         pool->size = size;
579         DO_STATS(pool->allocs = 0);
580         pool->pool = dma_pool_create(name, dev, size,
581                                      0 /* byte alignment */,
582                                      0 /* no page-crossing issues */);
583
584         return pool->pool ? 0 : -ENOMEM;
585 }
586
587 int
588 dmabounce_register_dev(struct device *dev, unsigned long small_buffer_size,
589                         unsigned long large_buffer_size)
590 {
591         struct dmabounce_device_info *device_info;
592         int ret;
593
594         device_info = kmalloc(sizeof(struct dmabounce_device_info), GFP_ATOMIC);
595         if (!device_info) {
596                 printk(KERN_ERR
597                         "Could not allocated dmabounce_device_info for %s",
598                         dev->bus_id);
599                 return -ENOMEM;
600         }
601
602         ret = dmabounce_init_pool(&device_info->small, dev,
603                                   "small_dmabounce_pool", small_buffer_size);
604         if (ret) {
605                 dev_err(dev,
606                         "dmabounce: could not allocate DMA pool for %ld byte objects\n",
607                         small_buffer_size);
608                 goto err_free;
609         }
610
611         if (large_buffer_size) {
612                 ret = dmabounce_init_pool(&device_info->large, dev,
613                                           "large_dmabounce_pool",
614                                           large_buffer_size);
615                 if (ret) {
616                         dev_err(dev,
617                                 "dmabounce: could not allocate DMA pool for %ld byte objects\n",
618                                 large_buffer_size);
619                         goto err_destroy;
620                 }
621         }
622
623         device_info->dev = dev;
624         INIT_LIST_HEAD(&device_info->safe_buffers);
625
626 #ifdef STATS
627         device_info->total_allocs = 0;
628         device_info->map_op_count = 0;
629         device_info->bounce_count = 0;
630 #endif
631
632         list_add(&device_info->node, &dmabounce_devs);
633
634         printk(KERN_INFO "dmabounce: registered device %s on %s bus\n",
635                 dev->bus_id, dev->bus->name);
636
637         return 0;
638
639  err_destroy:
640         dma_pool_destroy(device_info->small.pool);
641  err_free:
642         kfree(device_info);
643         return ret;
644 }
645
646 void
647 dmabounce_unregister_dev(struct device *dev)
648 {
649         struct dmabounce_device_info *device_info = find_dmabounce_dev(dev);
650
651         if (!device_info) {
652                 printk(KERN_WARNING
653                         "%s: Never registered with dmabounce but attempting" \
654                         "to unregister!\n", dev->bus_id);
655                 return;
656         }
657
658         if (!list_empty(&device_info->safe_buffers)) {
659                 printk(KERN_ERR
660                         "%s: Removing from dmabounce with pending buffers!\n",
661                         dev->bus_id);
662                 BUG();
663         }
664
665         if (device_info->small.pool)
666                 dma_pool_destroy(device_info->small.pool);
667         if (device_info->large.pool)
668                 dma_pool_destroy(device_info->large.pool);
669
670 #ifdef STATS
671         print_alloc_stats(device_info);
672         print_map_stats(device_info);
673 #endif
674
675         list_del(&device_info->node);
676
677         kfree(device_info);
678
679         printk(KERN_INFO "dmabounce: device %s on %s bus unregistered\n",
680                 dev->bus_id, dev->bus->name);
681 }
682
683
684 EXPORT_SYMBOL(dma_map_single);
685 EXPORT_SYMBOL(dma_unmap_single);
686 EXPORT_SYMBOL(dma_map_sg);
687 EXPORT_SYMBOL(dma_unmap_sg);
688 EXPORT_SYMBOL(dma_sync_single);
689 EXPORT_SYMBOL(dma_sync_sg);
690 EXPORT_SYMBOL(dmabounce_register_dev);
691 EXPORT_SYMBOL(dmabounce_unregister_dev);
692
693 MODULE_AUTHOR("Christopher Hoover <ch@hpl.hp.com>, Deepak Saxena <dsaxena@plexity.net>");
694 MODULE_DESCRIPTION("Special dma_{map/unmap/dma_sync}_* routines for systems with limited DMA windows");
695 MODULE_LICENSE("GPL");