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SFFSDR: Update to board code to support FPGA and lyrvpss drivers
[linux-davinci-sffsdr.git] / arch / arm / common / dmabounce.c
blobf030f0775be7d11016d14ed4add82c16be38d254
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/device.h>
29 #include <linux/dma-mapping.h>
30 #include <linux/dmapool.h>
31 #include <linux/list.h>
32 #include <linux/scatterlist.h>
33
34 #include <asm/cacheflush.h>
35
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 device *dev;
70 struct list_head safe_buffers;
71 #ifdef STATS
72 unsigned long total_allocs;
73 unsigned long map_op_count;
74 unsigned long bounce_count;
75 int attr_res;
76 #endif
77 struct dmabounce_pool small;
78 struct dmabounce_pool large;
79
80 rwlock_t lock;
81 };
82
83 #ifdef STATS
84 static ssize_t dmabounce_show(struct device *dev, struct device_attribute *attr,
85 char *buf)
86 {
87 struct dmabounce_device_info *device_info = dev->archdata.dmabounce;
88 return sprintf(buf, "%lu %lu %lu %lu %lu %lu\n",
89 device_info->small.allocs,
90 device_info->large.allocs,
91 device_info->total_allocs - device_info->small.allocs -
92 device_info->large.allocs,
93 device_info->total_allocs,
94 device_info->map_op_count,
95 device_info->bounce_count);
96 }
97
98 static DEVICE_ATTR(dmabounce_stats, 0400, dmabounce_show, NULL);
99 #endif
100
101
102 /* allocate a 'safe' buffer and keep track of it */
103 static inline struct safe_buffer *
104 alloc_safe_buffer(struct dmabounce_device_info *device_info, void *ptr,
105 size_t size, enum dma_data_direction dir)
106 {
107 struct safe_buffer *buf;
108 struct dmabounce_pool *pool;
109 struct device *dev = device_info->dev;
110 unsigned long flags;
111
112 dev_dbg(dev, "%s(ptr=%p, size=%d, dir=%d)\n",
113 __func__, ptr, size, dir);
114
115 if (size <= device_info->small.size) {
116 pool = &device_info->small;
117 } else if (size <= device_info->large.size) {
118 pool = &device_info->large;
119 } else {
120 pool = NULL;
121 }
122
123 buf = kmalloc(sizeof(struct safe_buffer), GFP_ATOMIC);
124 if (buf == NULL) {
125 dev_warn(dev, "%s: kmalloc failed\n", __func__);
126 return NULL;
127 }
128
129 buf->ptr = ptr;
130 buf->size = size;
131 buf->direction = dir;
132 buf->pool = pool;
133
134 if (pool) {
135 buf->safe = dma_pool_alloc(pool->pool, GFP_ATOMIC,
136 &buf->safe_dma_addr);
137 } else {
138 buf->safe = dma_alloc_coherent(dev, size, &buf->safe_dma_addr,
139 GFP_ATOMIC);
140 }
141
142 if (buf->safe == NULL) {
143 dev_warn(dev,
144 "%s: could not alloc dma memory (size=%d)\n",
145 __func__, size);
146 kfree(buf);
147 return NULL;
148 }
149
150 #ifdef STATS
151 if (pool)
152 pool->allocs++;
153 device_info->total_allocs++;
154 #endif
155
156 write_lock_irqsave(&device_info->lock, flags);
157 list_add(&buf->node, &device_info->safe_buffers);
158 write_unlock_irqrestore(&device_info->lock, flags);
159
160 return buf;
161 }
162
163 /* determine if a buffer is from our "safe" pool */
164 static inline struct safe_buffer *
165 find_safe_buffer(struct dmabounce_device_info *device_info, dma_addr_t safe_dma_addr)
166 {
167 struct safe_buffer *b, *rb = NULL;
168 unsigned long flags;
169
170 read_lock_irqsave(&device_info->lock, flags);
171
172 list_for_each_entry(b, &device_info->safe_buffers, node)
173 if (b->safe_dma_addr == safe_dma_addr) {
174 rb = b;
175 break;
176 }
177
178 read_unlock_irqrestore(&device_info->lock, flags);
179 return rb;
180 }
181
182 static inline void
183 free_safe_buffer(struct dmabounce_device_info *device_info, struct safe_buffer *buf)
184 {
185 unsigned long flags;
186
187 dev_dbg(device_info->dev, "%s(buf=%p)\n", __func__, buf);
188
189 write_lock_irqsave(&device_info->lock, flags);
190
191 list_del(&buf->node);
192
193 write_unlock_irqrestore(&device_info->lock, flags);
194
195 if (buf->pool)
196 dma_pool_free(buf->pool->pool, buf->safe, buf->safe_dma_addr);
197 else
198 dma_free_coherent(device_info->dev, buf->size, buf->safe,
199 buf->safe_dma_addr);
200
201 kfree(buf);
202 }
203
204 /* ************************************************** */
205
206 static struct safe_buffer *find_safe_buffer_dev(struct device *dev,
207 dma_addr_t dma_addr, const char *where)
208 {
209 if (!dev || !dev->archdata.dmabounce)
210 return NULL;
211 if (dma_mapping_error(dev, dma_addr)) {
212 if (dev)
213 dev_err(dev, "Trying to %s invalid mapping\n", where);
214 else
215 pr_err("unknown device: Trying to %s invalid mapping\n", where);
216 return NULL;
217 }
218 return find_safe_buffer(dev->archdata.dmabounce, dma_addr);
219 }
220
221 static inline dma_addr_t map_single(struct device *dev, void *ptr, size_t size,
222 enum dma_data_direction dir)
223 {
224 struct dmabounce_device_info *device_info = dev->archdata.dmabounce;
225 dma_addr_t dma_addr;
226 int needs_bounce = 0;
227
228 if (device_info)
229 DO_STATS ( device_info->map_op_count++ );
230
231 dma_addr = virt_to_dma(dev, ptr);
232
233 if (dev->dma_mask) {
234 unsigned long mask = *dev->dma_mask;
235 unsigned long limit;
236
237 limit = (mask + 1) & ~mask;
238 if (limit && size > limit) {
239 dev_err(dev, "DMA mapping too big (requested %#x "
240 "mask %#Lx)\n", size, *dev->dma_mask);
241 return ~0;
242 }
243
244 /*
245 * Figure out if we need to bounce from the DMA mask.
246 */
247 needs_bounce = (dma_addr | (dma_addr + size - 1)) & ~mask;
248 }
249
250 if (device_info && (needs_bounce || dma_needs_bounce(dev, dma_addr, size))) {
251 struct safe_buffer *buf;
252
253 buf = alloc_safe_buffer(device_info, ptr, size, dir);
254 if (buf == 0) {
255 dev_err(dev, "%s: unable to map unsafe buffer %p!\n",
256 __func__, ptr);
257 return 0;
258 }
259
260 dev_dbg(dev,
261 "%s: unsafe buffer %p (dma=%#x) mapped to %p (dma=%#x)\n",
262 __func__, buf->ptr, virt_to_dma(dev, buf->ptr),
263 buf->safe, buf->safe_dma_addr);
264
265 if ((dir == DMA_TO_DEVICE) ||
266 (dir == DMA_BIDIRECTIONAL)) {
267 dev_dbg(dev, "%s: copy unsafe %p to safe %p, size %d\n",
268 __func__, ptr, buf->safe, size);
269 memcpy(buf->safe, ptr, size);
270 }
271 ptr = buf->safe;
272
273 dma_addr = buf->safe_dma_addr;
274 } else {
275 /*
276 * We don't need to sync the DMA buffer since
277 * it was allocated via the coherent allocators.
278 */
279 dma_cache_maint(ptr, size, dir);
280 }
281
282 return dma_addr;
283 }
284
285 static inline void unmap_single(struct device *dev, dma_addr_t dma_addr,
286 size_t size, enum dma_data_direction dir)
287 {
288 struct safe_buffer *buf = find_safe_buffer_dev(dev, dma_addr, "unmap");
289
290 if (buf) {
291 BUG_ON(buf->size != size);
292 BUG_ON(buf->direction != dir);
293
294 dev_dbg(dev,
295 "%s: unsafe buffer %p (dma=%#x) mapped to %p (dma=%#x)\n",
296 __func__, buf->ptr, virt_to_dma(dev, buf->ptr),
297 buf->safe, buf->safe_dma_addr);
298
299 DO_STATS(dev->archdata.dmabounce->bounce_count++);
300
301 if (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL) {
302 void *ptr = buf->ptr;
303
304 dev_dbg(dev,
305 "%s: copy back safe %p to unsafe %p size %d\n",
306 __func__, buf->safe, ptr, size);
307 memcpy(ptr, buf->safe, size);
308
309 /*
310 * DMA buffers must have the same cache properties
311 * as if they were really used for DMA - which means
312 * data must be written back to RAM. Note that
313 * we don't use dmac_flush_range() here for the
314 * bidirectional case because we know the cache
315 * lines will be coherent with the data written.
316 */
317 dmac_clean_range(ptr, ptr + size);
318 outer_clean_range(__pa(ptr), __pa(ptr) + size);
319 }
320 free_safe_buffer(dev->archdata.dmabounce, buf);
321 }
322 }
323
324 /* ************************************************** */
325
326 /*
327 * see if a buffer address is in an 'unsafe' range. if it is
328 * allocate a 'safe' buffer and copy the unsafe buffer into it.
329 * substitute the safe buffer for the unsafe one.
330 * (basically move the buffer from an unsafe area to a safe one)
331 */
332 dma_addr_t dma_map_single(struct device *dev, void *ptr, size_t size,
333 enum dma_data_direction dir)
334 {
335 dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n",
336 __func__, ptr, size, dir);
337
338 BUG_ON(!valid_dma_direction(dir));
339
340 return map_single(dev, ptr, size, dir);
341 }
342 EXPORT_SYMBOL(dma_map_single);
343
344 dma_addr_t dma_map_page(struct device *dev, struct page *page,
345 unsigned long offset, size_t size, enum dma_data_direction dir)
346 {
347 dev_dbg(dev, "%s(page=%p,off=%#lx,size=%zx,dir=%x)\n",
348 __func__, page, offset, size, dir);
349
350 BUG_ON(!valid_dma_direction(dir));
351
352 return map_single(dev, page_address(page) + offset, size, dir);
353 }
354 EXPORT_SYMBOL(dma_map_page);
355
356 /*
357 * see if a mapped address was really a "safe" buffer and if so, copy
358 * the data from the safe buffer back to the unsafe buffer and free up
359 * the safe buffer. (basically return things back to the way they
360 * should be)
361 */
362
363 void dma_unmap_single(struct device *dev, dma_addr_t dma_addr, size_t size,
364 enum dma_data_direction dir)
365 {
366 dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n",
367 __func__, (void *) dma_addr, size, dir);
368
369 unmap_single(dev, dma_addr, size, dir);
370 }
371 EXPORT_SYMBOL(dma_unmap_single);
372
373 int dmabounce_sync_for_cpu(struct device *dev, dma_addr_t addr,
374 unsigned long off, size_t sz, enum dma_data_direction dir)
375 {
376 struct safe_buffer *buf;
377
378 dev_dbg(dev, "%s(dma=%#x,off=%#lx,sz=%zx,dir=%x)\n",
379 __func__, addr, off, sz, dir);
380
381 buf = find_safe_buffer_dev(dev, addr, __func__);
382 if (!buf)
383 return 1;
384
385 BUG_ON(buf->direction != dir);
386
387 dev_dbg(dev, "%s: unsafe buffer %p (dma=%#x) mapped to %p (dma=%#x)\n",
388 __func__, buf->ptr, virt_to_dma(dev, buf->ptr),
389 buf->safe, buf->safe_dma_addr);
390
391 DO_STATS(dev->archdata.dmabounce->bounce_count++);
392
393 if (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL) {
394 dev_dbg(dev, "%s: copy back safe %p to unsafe %p size %d\n",
395 __func__, buf->safe + off, buf->ptr + off, sz);
396 memcpy(buf->ptr + off, buf->safe + off, sz);
397 }
398 return 0;
399 }
400 EXPORT_SYMBOL(dmabounce_sync_for_cpu);
401
402 int dmabounce_sync_for_device(struct device *dev, dma_addr_t addr,
403 unsigned long off, size_t sz, enum dma_data_direction dir)
404 {
405 struct safe_buffer *buf;
406
407 dev_dbg(dev, "%s(dma=%#x,off=%#lx,sz=%zx,dir=%x)\n",
408 __func__, addr, off, sz, dir);
409
410 buf = find_safe_buffer_dev(dev, addr, __func__);
411 if (!buf)
412 return 1;
413
414 BUG_ON(buf->direction != dir);
415
416 dev_dbg(dev, "%s: unsafe buffer %p (dma=%#x) mapped to %p (dma=%#x)\n",
417 __func__, buf->ptr, virt_to_dma(dev, buf->ptr),
418 buf->safe, buf->safe_dma_addr);
419
420 DO_STATS(dev->archdata.dmabounce->bounce_count++);
421
422 if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL) {
423 dev_dbg(dev, "%s: copy out unsafe %p to safe %p, size %d\n",
424 __func__,buf->ptr + off, buf->safe + off, sz);
425 memcpy(buf->safe + off, buf->ptr + off, sz);
426 }
427 return 0;
428 }
429 EXPORT_SYMBOL(dmabounce_sync_for_device);
430
431 static int dmabounce_init_pool(struct dmabounce_pool *pool, struct device *dev,
432 const char *name, unsigned long size)
433 {
434 pool->size = size;
435 DO_STATS(pool->allocs = 0);
436 pool->pool = dma_pool_create(name, dev, size,
437 0 /* byte alignment */,
438 0 /* no page-crossing issues */);
439
440 return pool->pool ? 0 : -ENOMEM;
441 }
442
443 int dmabounce_register_dev(struct device *dev, unsigned long small_buffer_size,
444 unsigned long large_buffer_size)
445 {
446 struct dmabounce_device_info *device_info;
447 int ret;
448
449 device_info = kmalloc(sizeof(struct dmabounce_device_info), GFP_ATOMIC);
450 if (!device_info) {
451 dev_err(dev,
452 "Could not allocated dmabounce_device_info\n");
453 return -ENOMEM;
454 }
455
456 ret = dmabounce_init_pool(&device_info->small, dev,
457 "small_dmabounce_pool", small_buffer_size);
458 if (ret) {
459 dev_err(dev,
460 "dmabounce: could not allocate DMA pool for %ld byte objects\n",
461 small_buffer_size);
462 goto err_free;
463 }
464
465 if (large_buffer_size) {
466 ret = dmabounce_init_pool(&device_info->large, dev,
467 "large_dmabounce_pool",
468 large_buffer_size);
469 if (ret) {
470 dev_err(dev,
471 "dmabounce: could not allocate DMA pool for %ld byte objects\n",
472 large_buffer_size);
473 goto err_destroy;
474 }
475 }
476
477 device_info->dev = dev;
478 INIT_LIST_HEAD(&device_info->safe_buffers);
479 rwlock_init(&device_info->lock);
480
481 #ifdef STATS
482 device_info->total_allocs = 0;
483 device_info->map_op_count = 0;
484 device_info->bounce_count = 0;
485 device_info->attr_res = device_create_file(dev, &dev_attr_dmabounce_stats);
486 #endif
487
488 dev->archdata.dmabounce = device_info;
489
490 dev_info(dev, "dmabounce: registered device\n");
491
492 return 0;
493
494 err_destroy:
495 dma_pool_destroy(device_info->small.pool);
496 err_free:
497 kfree(device_info);
498 return ret;
499 }
500 EXPORT_SYMBOL(dmabounce_register_dev);
501
502 void dmabounce_unregister_dev(struct device *dev)
503 {
504 struct dmabounce_device_info *device_info = dev->archdata.dmabounce;
505
506 dev->archdata.dmabounce = NULL;
507
508 if (!device_info) {
509 dev_warn(dev,
510 "Never registered with dmabounce but attempting"
511 "to unregister!\n");
512 return;
513 }
514
515 if (!list_empty(&device_info->safe_buffers)) {
516 dev_err(dev,
517 "Removing from dmabounce with pending buffers!\n");
518 BUG();
519 }
520
521 if (device_info->small.pool)
522 dma_pool_destroy(device_info->small.pool);
523 if (device_info->large.pool)
524 dma_pool_destroy(device_info->large.pool);
525
526 #ifdef STATS
527 if (device_info->attr_res == 0)
528 device_remove_file(dev, &dev_attr_dmabounce_stats);
529 #endif
530
531 kfree(device_info);
532
533 dev_info(dev, "dmabounce: device unregistered\n");
534 }
535 EXPORT_SYMBOL(dmabounce_unregister_dev);
536
537 MODULE_AUTHOR("Christopher Hoover <ch@hpl.hp.com>, Deepak Saxena <dsaxena@plexity.net>");
538 MODULE_DESCRIPTION("Special dma_{map/unmap/dma_sync}_* routines for systems with limited DMA windows");
539 MODULE_LICENSE("GPL");
Linux for the Lyrtech SFFSDR board