ARM: dmabounce: correct unmap_single dev_dbg
[linux-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                 dev_err(dev, "Trying to %s invalid mapping\n", where);
214                 return NULL;
215         }
216         return find_safe_buffer(dev->archdata.dmabounce, dma_addr);
217 }
218
219 static int needs_bounce(struct device *dev, dma_addr_t dma_addr, size_t size)
220 {
221         if (!dev || !dev->archdata.dmabounce)
222                 return 0;
223
224         if (dev->dma_mask) {
225                 unsigned long limit, mask = *dev->dma_mask;
226
227                 limit = (mask + 1) & ~mask;
228                 if (limit && size > limit) {
229                         dev_err(dev, "DMA mapping too big (requested %#x "
230                                 "mask %#Lx)\n", size, *dev->dma_mask);
231                         return -E2BIG;
232                 }
233
234                 /* Figure out if we need to bounce from the DMA mask. */
235                 if ((dma_addr | (dma_addr + size - 1)) & ~mask)
236                         return 1;
237         }
238
239         return dma_needs_bounce(dev, dma_addr, size) ? 1 : 0;
240 }
241
242 static inline dma_addr_t map_single(struct device *dev, void *ptr, size_t size,
243                 enum dma_data_direction dir)
244 {
245         struct dmabounce_device_info *device_info = dev->archdata.dmabounce;
246         struct safe_buffer *buf;
247
248         if (device_info)
249                 DO_STATS ( device_info->map_op_count++ );
250
251         buf = alloc_safe_buffer(device_info, ptr, size, dir);
252         if (buf == NULL) {
253                 dev_err(dev, "%s: unable to map unsafe buffer %p!\n",
254                        __func__, ptr);
255                 return ~0;
256         }
257
258         dev_dbg(dev, "%s: unsafe buffer %p (dma=%#x) mapped to %p (dma=%#x)\n",
259                 __func__, buf->ptr, virt_to_dma(dev, buf->ptr),
260                 buf->safe, buf->safe_dma_addr);
261
262         if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL) {
263                 dev_dbg(dev, "%s: copy unsafe %p to safe %p, size %d\n",
264                         __func__, ptr, buf->safe, size);
265                 memcpy(buf->safe, ptr, size);
266         }
267
268         return buf->safe_dma_addr;
269 }
270
271 static inline void unmap_single(struct device *dev, struct safe_buffer *buf,
272                 size_t size, enum dma_data_direction dir)
273 {
274         BUG_ON(buf->size != size);
275         BUG_ON(buf->direction != dir);
276
277         dev_dbg(dev, "%s: unsafe buffer %p (dma=%#x) mapped to %p (dma=%#x)\n",
278                 __func__, buf->ptr, virt_to_dma(dev, buf->ptr),
279                 buf->safe, buf->safe_dma_addr);
280
281         DO_STATS(dev->archdata.dmabounce->bounce_count++);
282
283         if (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL) {
284                 void *ptr = buf->ptr;
285
286                 dev_dbg(dev, "%s: copy back safe %p to unsafe %p size %d\n",
287                         __func__, buf->safe, ptr, size);
288                 memcpy(ptr, buf->safe, size);
289
290                 /*
291                  * Since we may have written to a page cache page,
292                  * we need to ensure that the data will be coherent
293                  * with user mappings.
294                  */
295                 __cpuc_flush_dcache_area(ptr, size);
296         }
297         free_safe_buffer(dev->archdata.dmabounce, buf);
298 }
299
300 /* ************************************************** */
301
302 /*
303  * see if a buffer address is in an 'unsafe' range.  if it is
304  * allocate a 'safe' buffer and copy the unsafe buffer into it.
305  * substitute the safe buffer for the unsafe one.
306  * (basically move the buffer from an unsafe area to a safe one)
307  */
308 dma_addr_t __dma_map_page(struct device *dev, struct page *page,
309                 unsigned long offset, size_t size, enum dma_data_direction dir)
310 {
311         dma_addr_t dma_addr;
312         int ret;
313
314         dev_dbg(dev, "%s(page=%p,off=%#lx,size=%zx,dir=%x)\n",
315                 __func__, page, offset, size, dir);
316
317         dma_addr = pfn_to_dma(dev, page_to_pfn(page)) + offset;
318
319         ret = needs_bounce(dev, dma_addr, size);
320         if (ret < 0)
321                 return ~0;
322
323         if (ret == 0) {
324                 __dma_page_cpu_to_dev(page, offset, size, dir);
325                 return dma_addr;
326         }
327
328         if (PageHighMem(page)) {
329                 dev_err(dev, "DMA buffer bouncing of HIGHMEM pages is not supported\n");
330                 return ~0;
331         }
332
333         return map_single(dev, page_address(page) + offset, size, dir);
334 }
335 EXPORT_SYMBOL(__dma_map_page);
336
337 /*
338  * see if a mapped address was really a "safe" buffer and if so, copy
339  * the data from the safe buffer back to the unsafe buffer and free up
340  * the safe buffer.  (basically return things back to the way they
341  * should be)
342  */
343 void __dma_unmap_page(struct device *dev, dma_addr_t dma_addr, size_t size,
344                 enum dma_data_direction dir)
345 {
346         struct safe_buffer *buf;
347
348         dev_dbg(dev, "%s(dma=%#x,size=%d,dir=%x)\n",
349                 __func__, dma_addr, size, dir);
350
351         buf = find_safe_buffer_dev(dev, dma_addr, __func__);
352         if (!buf) {
353                 __dma_page_dev_to_cpu(pfn_to_page(dma_to_pfn(dev, dma_addr)),
354                         dma_addr & ~PAGE_MASK, size, dir);
355                 return;
356         }
357
358         unmap_single(dev, buf, size, dir);
359 }
360 EXPORT_SYMBOL(__dma_unmap_page);
361
362 int dmabounce_sync_for_cpu(struct device *dev, dma_addr_t addr,
363                 unsigned long off, size_t sz, enum dma_data_direction dir)
364 {
365         struct safe_buffer *buf;
366
367         dev_dbg(dev, "%s(dma=%#x,off=%#lx,sz=%zx,dir=%x)\n",
368                 __func__, addr, off, sz, dir);
369
370         buf = find_safe_buffer_dev(dev, addr, __func__);
371         if (!buf)
372                 return 1;
373
374         BUG_ON(buf->direction != dir);
375
376         dev_dbg(dev, "%s: unsafe buffer %p (dma=%#x) mapped to %p (dma=%#x)\n",
377                 __func__, buf->ptr, virt_to_dma(dev, buf->ptr),
378                 buf->safe, buf->safe_dma_addr);
379
380         DO_STATS(dev->archdata.dmabounce->bounce_count++);
381
382         if (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL) {
383                 dev_dbg(dev, "%s: copy back safe %p to unsafe %p size %d\n",
384                         __func__, buf->safe + off, buf->ptr + off, sz);
385                 memcpy(buf->ptr + off, buf->safe + off, sz);
386         }
387         return 0;
388 }
389 EXPORT_SYMBOL(dmabounce_sync_for_cpu);
390
391 int dmabounce_sync_for_device(struct device *dev, dma_addr_t addr,
392                 unsigned long off, size_t sz, enum dma_data_direction dir)
393 {
394         struct safe_buffer *buf;
395
396         dev_dbg(dev, "%s(dma=%#x,off=%#lx,sz=%zx,dir=%x)\n",
397                 __func__, addr, off, sz, dir);
398
399         buf = find_safe_buffer_dev(dev, addr, __func__);
400         if (!buf)
401                 return 1;
402
403         BUG_ON(buf->direction != dir);
404
405         dev_dbg(dev, "%s: unsafe buffer %p (dma=%#x) mapped to %p (dma=%#x)\n",
406                 __func__, buf->ptr, virt_to_dma(dev, buf->ptr),
407                 buf->safe, buf->safe_dma_addr);
408
409         DO_STATS(dev->archdata.dmabounce->bounce_count++);
410
411         if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL) {
412                 dev_dbg(dev, "%s: copy out unsafe %p to safe %p, size %d\n",
413                         __func__,buf->ptr + off, buf->safe + off, sz);
414                 memcpy(buf->safe + off, buf->ptr + off, sz);
415         }
416         return 0;
417 }
418 EXPORT_SYMBOL(dmabounce_sync_for_device);
419
420 static int dmabounce_init_pool(struct dmabounce_pool *pool, struct device *dev,
421                 const char *name, unsigned long size)
422 {
423         pool->size = size;
424         DO_STATS(pool->allocs = 0);
425         pool->pool = dma_pool_create(name, dev, size,
426                                      0 /* byte alignment */,
427                                      0 /* no page-crossing issues */);
428
429         return pool->pool ? 0 : -ENOMEM;
430 }
431
432 int dmabounce_register_dev(struct device *dev, unsigned long small_buffer_size,
433                 unsigned long large_buffer_size)
434 {
435         struct dmabounce_device_info *device_info;
436         int ret;
437
438         device_info = kmalloc(sizeof(struct dmabounce_device_info), GFP_ATOMIC);
439         if (!device_info) {
440                 dev_err(dev,
441                         "Could not allocated dmabounce_device_info\n");
442                 return -ENOMEM;
443         }
444
445         ret = dmabounce_init_pool(&device_info->small, dev,
446                                   "small_dmabounce_pool", small_buffer_size);
447         if (ret) {
448                 dev_err(dev,
449                         "dmabounce: could not allocate DMA pool for %ld byte objects\n",
450                         small_buffer_size);
451                 goto err_free;
452         }
453
454         if (large_buffer_size) {
455                 ret = dmabounce_init_pool(&device_info->large, dev,
456                                           "large_dmabounce_pool",
457                                           large_buffer_size);
458                 if (ret) {
459                         dev_err(dev,
460                                 "dmabounce: could not allocate DMA pool for %ld byte objects\n",
461                                 large_buffer_size);
462                         goto err_destroy;
463                 }
464         }
465
466         device_info->dev = dev;
467         INIT_LIST_HEAD(&device_info->safe_buffers);
468         rwlock_init(&device_info->lock);
469
470 #ifdef STATS
471         device_info->total_allocs = 0;
472         device_info->map_op_count = 0;
473         device_info->bounce_count = 0;
474         device_info->attr_res = device_create_file(dev, &dev_attr_dmabounce_stats);
475 #endif
476
477         dev->archdata.dmabounce = device_info;
478
479         dev_info(dev, "dmabounce: registered device\n");
480
481         return 0;
482
483  err_destroy:
484         dma_pool_destroy(device_info->small.pool);
485  err_free:
486         kfree(device_info);
487         return ret;
488 }
489 EXPORT_SYMBOL(dmabounce_register_dev);
490
491 void dmabounce_unregister_dev(struct device *dev)
492 {
493         struct dmabounce_device_info *device_info = dev->archdata.dmabounce;
494
495         dev->archdata.dmabounce = NULL;
496
497         if (!device_info) {
498                 dev_warn(dev,
499                          "Never registered with dmabounce but attempting"
500                          "to unregister!\n");
501                 return;
502         }
503
504         if (!list_empty(&device_info->safe_buffers)) {
505                 dev_err(dev,
506                         "Removing from dmabounce with pending buffers!\n");
507                 BUG();
508         }
509
510         if (device_info->small.pool)
511                 dma_pool_destroy(device_info->small.pool);
512         if (device_info->large.pool)
513                 dma_pool_destroy(device_info->large.pool);
514
515 #ifdef STATS
516         if (device_info->attr_res == 0)
517                 device_remove_file(dev, &dev_attr_dmabounce_stats);
518 #endif
519
520         kfree(device_info);
521
522         dev_info(dev, "dmabounce: device unregistered\n");
523 }
524 EXPORT_SYMBOL(dmabounce_unregister_dev);
525
526 MODULE_AUTHOR("Christopher Hoover <ch@hpl.hp.com>, Deepak Saxena <dsaxena@plexity.net>");
527 MODULE_DESCRIPTION("Special dma_{map/unmap/dma_sync}_* routines for systems with limited DMA windows");
528 MODULE_LICENSE("GPL");