Merge branches 'at91', 'cache', 'cup', 'ep93xx', 'ixp4xx', 'nuc', 'pending-dma-stream...
[sfrench/cifs-2.6.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 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/page-flags.h>
29 #include <linux/device.h>
30 #include <linux/dma-mapping.h>
31 #include <linux/dmapool.h>
32 #include <linux/list.h>
33 #include <linux/scatterlist.h>
34
35 #include <asm/cacheflush.h>
36
37 #undef STATS
38
39 #ifdef STATS
40 #define DO_STATS(X) do { X ; } while (0)
41 #else
42 #define DO_STATS(X) do { } while (0)
43 #endif
44
45 /* ************************************************** */
46
47 struct safe_buffer {
48         struct list_head node;
49
50         /* original request */
51         void            *ptr;
52         size_t          size;
53         int             direction;
54
55         /* safe buffer info */
56         struct dmabounce_pool *pool;
57         void            *safe;
58         dma_addr_t      safe_dma_addr;
59 };
60
61 struct dmabounce_pool {
62         unsigned long   size;
63         struct dma_pool *pool;
64 #ifdef STATS
65         unsigned long   allocs;
66 #endif
67 };
68
69 struct dmabounce_device_info {
70         struct device *dev;
71         struct list_head safe_buffers;
72 #ifdef STATS
73         unsigned long total_allocs;
74         unsigned long map_op_count;
75         unsigned long bounce_count;
76         int attr_res;
77 #endif
78         struct dmabounce_pool   small;
79         struct dmabounce_pool   large;
80
81         rwlock_t lock;
82 };
83
84 #ifdef STATS
85 static ssize_t dmabounce_show(struct device *dev, struct device_attribute *attr,
86                               char *buf)
87 {
88         struct dmabounce_device_info *device_info = dev->archdata.dmabounce;
89         return sprintf(buf, "%lu %lu %lu %lu %lu %lu\n",
90                 device_info->small.allocs,
91                 device_info->large.allocs,
92                 device_info->total_allocs - device_info->small.allocs -
93                         device_info->large.allocs,
94                 device_info->total_allocs,
95                 device_info->map_op_count,
96                 device_info->bounce_count);
97 }
98
99 static DEVICE_ATTR(dmabounce_stats, 0400, dmabounce_show, NULL);
100 #endif
101
102
103 /* allocate a 'safe' buffer and keep track of it */
104 static inline struct safe_buffer *
105 alloc_safe_buffer(struct dmabounce_device_info *device_info, void *ptr,
106                   size_t size, enum dma_data_direction dir)
107 {
108         struct safe_buffer *buf;
109         struct dmabounce_pool *pool;
110         struct device *dev = device_info->dev;
111         unsigned long flags;
112
113         dev_dbg(dev, "%s(ptr=%p, size=%d, dir=%d)\n",
114                 __func__, ptr, size, dir);
115
116         if (size <= device_info->small.size) {
117                 pool = &device_info->small;
118         } else if (size <= device_info->large.size) {
119                 pool = &device_info->large;
120         } else {
121                 pool = NULL;
122         }
123
124         buf = kmalloc(sizeof(struct safe_buffer), GFP_ATOMIC);
125         if (buf == NULL) {
126                 dev_warn(dev, "%s: kmalloc failed\n", __func__);
127                 return NULL;
128         }
129
130         buf->ptr = ptr;
131         buf->size = size;
132         buf->direction = dir;
133         buf->pool = pool;
134
135         if (pool) {
136                 buf->safe = dma_pool_alloc(pool->pool, GFP_ATOMIC,
137                                            &buf->safe_dma_addr);
138         } else {
139                 buf->safe = dma_alloc_coherent(dev, size, &buf->safe_dma_addr,
140                                                GFP_ATOMIC);
141         }
142
143         if (buf->safe == NULL) {
144                 dev_warn(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 (pool)
153                 pool->allocs++;
154         device_info->total_allocs++;
155 #endif
156
157         write_lock_irqsave(&device_info->lock, flags);
158         list_add(&buf->node, &device_info->safe_buffers);
159         write_unlock_irqrestore(&device_info->lock, flags);
160
161         return buf;
162 }
163
164 /* determine if a buffer is from our "safe" pool */
165 static inline struct safe_buffer *
166 find_safe_buffer(struct dmabounce_device_info *device_info, dma_addr_t safe_dma_addr)
167 {
168         struct safe_buffer *b, *rb = NULL;
169         unsigned long flags;
170
171         read_lock_irqsave(&device_info->lock, flags);
172
173         list_for_each_entry(b, &device_info->safe_buffers, node)
174                 if (b->safe_dma_addr == safe_dma_addr) {
175                         rb = b;
176                         break;
177                 }
178
179         read_unlock_irqrestore(&device_info->lock, flags);
180         return rb;
181 }
182
183 static inline void
184 free_safe_buffer(struct dmabounce_device_info *device_info, struct safe_buffer *buf)
185 {
186         unsigned long flags;
187
188         dev_dbg(device_info->dev, "%s(buf=%p)\n", __func__, buf);
189
190         write_lock_irqsave(&device_info->lock, flags);
191
192         list_del(&buf->node);
193
194         write_unlock_irqrestore(&device_info->lock, flags);
195
196         if (buf->pool)
197                 dma_pool_free(buf->pool->pool, buf->safe, buf->safe_dma_addr);
198         else
199                 dma_free_coherent(device_info->dev, buf->size, buf->safe,
200                                     buf->safe_dma_addr);
201
202         kfree(buf);
203 }
204
205 /* ************************************************** */
206
207 static struct safe_buffer *find_safe_buffer_dev(struct device *dev,
208                 dma_addr_t dma_addr, const char *where)
209 {
210         if (!dev || !dev->archdata.dmabounce)
211                 return NULL;
212         if (dma_mapping_error(dev, dma_addr)) {
213                 if (dev)
214                         dev_err(dev, "Trying to %s invalid mapping\n", where);
215                 else
216                         pr_err("unknown device: Trying to %s invalid mapping\n", where);
217                 return NULL;
218         }
219         return find_safe_buffer(dev->archdata.dmabounce, dma_addr);
220 }
221
222 static inline dma_addr_t map_single(struct device *dev, void *ptr, size_t size,
223                 enum dma_data_direction dir)
224 {
225         struct dmabounce_device_info *device_info = dev->archdata.dmabounce;
226         dma_addr_t dma_addr;
227         int needs_bounce = 0;
228
229         if (device_info)
230                 DO_STATS ( device_info->map_op_count++ );
231
232         dma_addr = virt_to_dma(dev, ptr);
233
234         if (dev->dma_mask) {
235                 unsigned long mask = *dev->dma_mask;
236                 unsigned long limit;
237
238                 limit = (mask + 1) & ~mask;
239                 if (limit && size > limit) {
240                         dev_err(dev, "DMA mapping too big (requested %#x "
241                                 "mask %#Lx)\n", size, *dev->dma_mask);
242                         return ~0;
243                 }
244
245                 /*
246                  * Figure out if we need to bounce from the DMA mask.
247                  */
248                 needs_bounce = (dma_addr | (dma_addr + size - 1)) & ~mask;
249         }
250
251         if (device_info && (needs_bounce || dma_needs_bounce(dev, dma_addr, size))) {
252                 struct safe_buffer *buf;
253
254                 buf = alloc_safe_buffer(device_info, ptr, size, dir);
255                 if (buf == 0) {
256                         dev_err(dev, "%s: unable to map unsafe buffer %p!\n",
257                                __func__, ptr);
258                         return 0;
259                 }
260
261                 dev_dbg(dev,
262                         "%s: unsafe buffer %p (dma=%#x) mapped to %p (dma=%#x)\n",
263                         __func__, buf->ptr, virt_to_dma(dev, buf->ptr),
264                         buf->safe, buf->safe_dma_addr);
265
266                 if ((dir == DMA_TO_DEVICE) ||
267                     (dir == DMA_BIDIRECTIONAL)) {
268                         dev_dbg(dev, "%s: copy unsafe %p to safe %p, size %d\n",
269                                 __func__, ptr, buf->safe, size);
270                         memcpy(buf->safe, ptr, size);
271                 }
272                 ptr = buf->safe;
273
274                 dma_addr = buf->safe_dma_addr;
275         } else {
276                 /*
277                  * We don't need to sync the DMA buffer since
278                  * it was allocated via the coherent allocators.
279                  */
280                 __dma_single_cpu_to_dev(ptr, size, dir);
281         }
282
283         return dma_addr;
284 }
285
286 static inline void unmap_single(struct device *dev, dma_addr_t dma_addr,
287                 size_t size, enum dma_data_direction dir)
288 {
289         struct safe_buffer *buf = find_safe_buffer_dev(dev, dma_addr, "unmap");
290
291         if (buf) {
292                 BUG_ON(buf->size != size);
293                 BUG_ON(buf->direction != dir);
294
295                 dev_dbg(dev,
296                         "%s: unsafe buffer %p (dma=%#x) mapped to %p (dma=%#x)\n",
297                         __func__, buf->ptr, virt_to_dma(dev, buf->ptr),
298                         buf->safe, buf->safe_dma_addr);
299
300                 DO_STATS(dev->archdata.dmabounce->bounce_count++);
301
302                 if (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL) {
303                         void *ptr = buf->ptr;
304
305                         dev_dbg(dev,
306                                 "%s: copy back safe %p to unsafe %p size %d\n",
307                                 __func__, buf->safe, ptr, size);
308                         memcpy(ptr, buf->safe, size);
309
310                         /*
311                          * Since we may have written to a page cache page,
312                          * we need to ensure that the data will be coherent
313                          * with user mappings.
314                          */
315                         __cpuc_flush_dcache_area(ptr, size);
316                 }
317                 free_safe_buffer(dev->archdata.dmabounce, buf);
318         } else {
319                 __dma_single_dev_to_cpu(dma_to_virt(dev, dma_addr), size, dir);
320         }
321 }
322
323 /* ************************************************** */
324
325 /*
326  * see if a buffer address is in an 'unsafe' range.  if it is
327  * allocate a 'safe' buffer and copy the unsafe buffer into it.
328  * substitute the safe buffer for the unsafe one.
329  * (basically move the buffer from an unsafe area to a safe one)
330  */
331 dma_addr_t dma_map_single(struct device *dev, void *ptr, size_t size,
332                 enum dma_data_direction dir)
333 {
334         dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n",
335                 __func__, ptr, size, dir);
336
337         BUG_ON(!valid_dma_direction(dir));
338
339         return map_single(dev, ptr, size, dir);
340 }
341 EXPORT_SYMBOL(dma_map_single);
342
343 /*
344  * see if a mapped address was really a "safe" buffer and if so, copy
345  * the data from the safe buffer back to the unsafe buffer and free up
346  * the safe buffer.  (basically return things back to the way they
347  * should be)
348  */
349 void dma_unmap_single(struct device *dev, dma_addr_t dma_addr, size_t size,
350                 enum dma_data_direction dir)
351 {
352         dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n",
353                 __func__, (void *) dma_addr, size, dir);
354
355         unmap_single(dev, dma_addr, size, dir);
356 }
357 EXPORT_SYMBOL(dma_unmap_single);
358
359 dma_addr_t dma_map_page(struct device *dev, struct page *page,
360                 unsigned long offset, size_t size, enum dma_data_direction dir)
361 {
362         dev_dbg(dev, "%s(page=%p,off=%#lx,size=%zx,dir=%x)\n",
363                 __func__, page, offset, size, dir);
364
365         BUG_ON(!valid_dma_direction(dir));
366
367         if (PageHighMem(page)) {
368                 dev_err(dev, "DMA buffer bouncing of HIGHMEM pages "
369                              "is not supported\n");
370                 return ~0;
371         }
372
373         return map_single(dev, page_address(page) + offset, size, dir);
374 }
375 EXPORT_SYMBOL(dma_map_page);
376
377 /*
378  * see if a mapped address was really a "safe" buffer and if so, copy
379  * the data from the safe buffer back to the unsafe buffer and free up
380  * the safe buffer.  (basically return things back to the way they
381  * should be)
382  */
383 void dma_unmap_page(struct device *dev, dma_addr_t dma_addr, size_t size,
384                 enum dma_data_direction dir)
385 {
386         dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n",
387                 __func__, (void *) dma_addr, size, dir);
388
389         unmap_single(dev, dma_addr, size, dir);
390 }
391 EXPORT_SYMBOL(dma_unmap_page);
392
393 int dmabounce_sync_for_cpu(struct device *dev, dma_addr_t addr,
394                 unsigned long off, size_t sz, enum dma_data_direction dir)
395 {
396         struct safe_buffer *buf;
397
398         dev_dbg(dev, "%s(dma=%#x,off=%#lx,sz=%zx,dir=%x)\n",
399                 __func__, addr, off, sz, dir);
400
401         buf = find_safe_buffer_dev(dev, addr, __func__);
402         if (!buf)
403                 return 1;
404
405         BUG_ON(buf->direction != dir);
406
407         dev_dbg(dev, "%s: unsafe buffer %p (dma=%#x) mapped to %p (dma=%#x)\n",
408                 __func__, buf->ptr, virt_to_dma(dev, buf->ptr),
409                 buf->safe, buf->safe_dma_addr);
410
411         DO_STATS(dev->archdata.dmabounce->bounce_count++);
412
413         if (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL) {
414                 dev_dbg(dev, "%s: copy back safe %p to unsafe %p size %d\n",
415                         __func__, buf->safe + off, buf->ptr + off, sz);
416                 memcpy(buf->ptr + off, buf->safe + off, sz);
417         }
418         return 0;
419 }
420 EXPORT_SYMBOL(dmabounce_sync_for_cpu);
421
422 int dmabounce_sync_for_device(struct device *dev, dma_addr_t addr,
423                 unsigned long off, size_t sz, enum dma_data_direction dir)
424 {
425         struct safe_buffer *buf;
426
427         dev_dbg(dev, "%s(dma=%#x,off=%#lx,sz=%zx,dir=%x)\n",
428                 __func__, addr, off, sz, dir);
429
430         buf = find_safe_buffer_dev(dev, addr, __func__);
431         if (!buf)
432                 return 1;
433
434         BUG_ON(buf->direction != dir);
435
436         dev_dbg(dev, "%s: unsafe buffer %p (dma=%#x) mapped to %p (dma=%#x)\n",
437                 __func__, buf->ptr, virt_to_dma(dev, buf->ptr),
438                 buf->safe, buf->safe_dma_addr);
439
440         DO_STATS(dev->archdata.dmabounce->bounce_count++);
441
442         if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL) {
443                 dev_dbg(dev, "%s: copy out unsafe %p to safe %p, size %d\n",
444                         __func__,buf->ptr + off, buf->safe + off, sz);
445                 memcpy(buf->safe + off, buf->ptr + off, sz);
446         }
447         return 0;
448 }
449 EXPORT_SYMBOL(dmabounce_sync_for_device);
450
451 static int dmabounce_init_pool(struct dmabounce_pool *pool, struct device *dev,
452                 const char *name, unsigned long size)
453 {
454         pool->size = size;
455         DO_STATS(pool->allocs = 0);
456         pool->pool = dma_pool_create(name, dev, size,
457                                      0 /* byte alignment */,
458                                      0 /* no page-crossing issues */);
459
460         return pool->pool ? 0 : -ENOMEM;
461 }
462
463 int dmabounce_register_dev(struct device *dev, unsigned long small_buffer_size,
464                 unsigned long large_buffer_size)
465 {
466         struct dmabounce_device_info *device_info;
467         int ret;
468
469         device_info = kmalloc(sizeof(struct dmabounce_device_info), GFP_ATOMIC);
470         if (!device_info) {
471                 dev_err(dev,
472                         "Could not allocated dmabounce_device_info\n");
473                 return -ENOMEM;
474         }
475
476         ret = dmabounce_init_pool(&device_info->small, dev,
477                                   "small_dmabounce_pool", small_buffer_size);
478         if (ret) {
479                 dev_err(dev,
480                         "dmabounce: could not allocate DMA pool for %ld byte objects\n",
481                         small_buffer_size);
482                 goto err_free;
483         }
484
485         if (large_buffer_size) {
486                 ret = dmabounce_init_pool(&device_info->large, dev,
487                                           "large_dmabounce_pool",
488                                           large_buffer_size);
489                 if (ret) {
490                         dev_err(dev,
491                                 "dmabounce: could not allocate DMA pool for %ld byte objects\n",
492                                 large_buffer_size);
493                         goto err_destroy;
494                 }
495         }
496
497         device_info->dev = dev;
498         INIT_LIST_HEAD(&device_info->safe_buffers);
499         rwlock_init(&device_info->lock);
500
501 #ifdef STATS
502         device_info->total_allocs = 0;
503         device_info->map_op_count = 0;
504         device_info->bounce_count = 0;
505         device_info->attr_res = device_create_file(dev, &dev_attr_dmabounce_stats);
506 #endif
507
508         dev->archdata.dmabounce = device_info;
509
510         dev_info(dev, "dmabounce: registered device\n");
511
512         return 0;
513
514  err_destroy:
515         dma_pool_destroy(device_info->small.pool);
516  err_free:
517         kfree(device_info);
518         return ret;
519 }
520 EXPORT_SYMBOL(dmabounce_register_dev);
521
522 void dmabounce_unregister_dev(struct device *dev)
523 {
524         struct dmabounce_device_info *device_info = dev->archdata.dmabounce;
525
526         dev->archdata.dmabounce = NULL;
527
528         if (!device_info) {
529                 dev_warn(dev,
530                          "Never registered with dmabounce but attempting"
531                          "to unregister!\n");
532                 return;
533         }
534
535         if (!list_empty(&device_info->safe_buffers)) {
536                 dev_err(dev,
537                         "Removing from dmabounce with pending buffers!\n");
538                 BUG();
539         }
540
541         if (device_info->small.pool)
542                 dma_pool_destroy(device_info->small.pool);
543         if (device_info->large.pool)
544                 dma_pool_destroy(device_info->large.pool);
545
546 #ifdef STATS
547         if (device_info->attr_res == 0)
548                 device_remove_file(dev, &dev_attr_dmabounce_stats);
549 #endif
550
551         kfree(device_info);
552
553         dev_info(dev, "dmabounce: device unregistered\n");
554 }
555 EXPORT_SYMBOL(dmabounce_unregister_dev);
556
557 MODULE_AUTHOR("Christopher Hoover <ch@hpl.hp.com>, Deepak Saxena <dsaxena@plexity.net>");
558 MODULE_DESCRIPTION("Special dma_{map/unmap/dma_sync}_* routines for systems with limited DMA windows");
559 MODULE_LICENSE("GPL");