Merge master.kernel.org:/pub/scm/linux/kernel/git/sfrench/cifs-2.6
[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 STATS
36
37 #ifdef STATS
38 #define DO_STATS(X) do { X ; } while (0)
39 #else
40 #define DO_STATS(X) do { } while (0)
41 #endif
42
43 /* ************************************************** */
44
45 struct safe_buffer {
46         struct list_head node;
47
48         /* original request */
49         void            *ptr;
50         size_t          size;
51         int             direction;
52
53         /* safe buffer info */
54         struct dmabounce_pool *pool;
55         void            *safe;
56         dma_addr_t      safe_dma_addr;
57 };
58
59 struct dmabounce_pool {
60         unsigned long   size;
61         struct dma_pool *pool;
62 #ifdef STATS
63         unsigned long   allocs;
64 #endif
65 };
66
67 struct dmabounce_device_info {
68         struct device *dev;
69         struct list_head safe_buffers;
70 #ifdef STATS
71         unsigned long total_allocs;
72         unsigned long map_op_count;
73         unsigned long bounce_count;
74         int attr_res;
75 #endif
76         struct dmabounce_pool   small;
77         struct dmabounce_pool   large;
78
79         rwlock_t lock;
80 };
81
82 #ifdef STATS
83 static ssize_t dmabounce_show(struct device *dev, struct device_attribute *attr,
84                               char *buf)
85 {
86         struct dmabounce_device_info *device_info = dev->archdata.dmabounce;
87         return sprintf(buf, "%lu %lu %lu %lu %lu %lu\n",
88                 device_info->small.allocs,
89                 device_info->large.allocs,
90                 device_info->total_allocs - device_info->small.allocs -
91                         device_info->large.allocs,
92                 device_info->total_allocs,
93                 device_info->map_op_count,
94                 device_info->bounce_count);
95 }
96
97 static DEVICE_ATTR(dmabounce_stats, 0400, dmabounce_show, NULL);
98 #endif
99
100
101 /* allocate a 'safe' buffer and keep track of it */
102 static inline struct safe_buffer *
103 alloc_safe_buffer(struct dmabounce_device_info *device_info, void *ptr,
104                   size_t size, enum dma_data_direction dir)
105 {
106         struct safe_buffer *buf;
107         struct dmabounce_pool *pool;
108         struct device *dev = device_info->dev;
109         unsigned long flags;
110
111         dev_dbg(dev, "%s(ptr=%p, size=%d, dir=%d)\n",
112                 __func__, ptr, size, dir);
113
114         if (size <= device_info->small.size) {
115                 pool = &device_info->small;
116         } else if (size <= device_info->large.size) {
117                 pool = &device_info->large;
118         } else {
119                 pool = NULL;
120         }
121
122         buf = kmalloc(sizeof(struct safe_buffer), GFP_ATOMIC);
123         if (buf == NULL) {
124                 dev_warn(dev, "%s: kmalloc failed\n", __func__);
125                 return NULL;
126         }
127
128         buf->ptr = ptr;
129         buf->size = size;
130         buf->direction = dir;
131         buf->pool = pool;
132
133         if (pool) {
134                 buf->safe = dma_pool_alloc(pool->pool, GFP_ATOMIC,
135                                            &buf->safe_dma_addr);
136         } else {
137                 buf->safe = dma_alloc_coherent(dev, size, &buf->safe_dma_addr,
138                                                GFP_ATOMIC);
139         }
140
141         if (buf->safe == NULL) {
142                 dev_warn(dev,
143                          "%s: could not alloc dma memory (size=%d)\n",
144                          __func__, size);
145                 kfree(buf);
146                 return NULL;
147         }
148
149 #ifdef STATS
150         if (pool)
151                 pool->allocs++;
152         device_info->total_allocs++;
153 #endif
154
155         write_lock_irqsave(&device_info->lock, flags);
156
157         list_add(&buf->node, &device_info->safe_buffers);
158
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 inline dma_addr_t
208 map_single(struct device *dev, void *ptr, size_t size,
209                 enum dma_data_direction dir)
210 {
211         struct dmabounce_device_info *device_info = dev->archdata.dmabounce;
212         dma_addr_t dma_addr;
213         int needs_bounce = 0;
214
215         if (device_info)
216                 DO_STATS ( device_info->map_op_count++ );
217
218         dma_addr = virt_to_dma(dev, ptr);
219
220         if (dev->dma_mask) {
221                 unsigned long mask = *dev->dma_mask;
222                 unsigned long limit;
223
224                 limit = (mask + 1) & ~mask;
225                 if (limit && size > limit) {
226                         dev_err(dev, "DMA mapping too big (requested %#x "
227                                 "mask %#Lx)\n", size, *dev->dma_mask);
228                         return ~0;
229                 }
230
231                 /*
232                  * Figure out if we need to bounce from the DMA mask.
233                  */
234                 needs_bounce = (dma_addr | (dma_addr + size - 1)) & ~mask;
235         }
236
237         if (device_info && (needs_bounce || dma_needs_bounce(dev, dma_addr, size))) {
238                 struct safe_buffer *buf;
239
240                 buf = alloc_safe_buffer(device_info, ptr, size, dir);
241                 if (buf == 0) {
242                         dev_err(dev, "%s: unable to map unsafe buffer %p!\n",
243                                __func__, ptr);
244                         return 0;
245                 }
246
247                 dev_dbg(dev,
248                         "%s: unsafe buffer %p (phy=%p) mapped to %p (phy=%p)\n",
249                         __func__, buf->ptr, (void *) virt_to_dma(dev, buf->ptr),
250                         buf->safe, (void *) buf->safe_dma_addr);
251
252                 if ((dir == DMA_TO_DEVICE) ||
253                     (dir == DMA_BIDIRECTIONAL)) {
254                         dev_dbg(dev, "%s: copy unsafe %p to safe %p, size %d\n",
255                                 __func__, ptr, buf->safe, size);
256                         memcpy(buf->safe, ptr, size);
257                 }
258                 ptr = buf->safe;
259
260                 dma_addr = buf->safe_dma_addr;
261         } else {
262                 /*
263                  * We don't need to sync the DMA buffer since
264                  * it was allocated via the coherent allocators.
265                  */
266                 consistent_sync(ptr, size, dir);
267         }
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 = dev->archdata.dmabounce;
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                         void *ptr = buf->ptr;
302
303                         dev_dbg(dev,
304                                 "%s: copy back safe %p to unsafe %p size %d\n",
305                                 __func__, buf->safe, ptr, size);
306                         memcpy(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                         dmac_clean_range(ptr, ptr + size);
317                         outer_clean_range(__pa(ptr), __pa(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 = dev->archdata.dmabounce;
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                 /*
382                  * No need to sync the safe buffer - it was allocated
383                  * via the coherent allocators.
384                  */
385         } else {
386                 consistent_sync(dma_to_virt(dev, dma_addr), size, dir);
387         }
388 }
389
390 /* ************************************************** */
391
392 /*
393  * see if a buffer address is in an 'unsafe' range.  if it is
394  * allocate a 'safe' buffer and copy the unsafe buffer into it.
395  * substitute the safe buffer for the unsafe one.
396  * (basically move the buffer from an unsafe area to a safe one)
397  */
398 dma_addr_t
399 dma_map_single(struct device *dev, void *ptr, size_t size,
400                 enum dma_data_direction dir)
401 {
402         dma_addr_t dma_addr;
403
404         dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n",
405                 __func__, ptr, size, dir);
406
407         BUG_ON(dir == DMA_NONE);
408
409         dma_addr = map_single(dev, ptr, size, dir);
410
411         return dma_addr;
412 }
413
414 /*
415  * see if a mapped address was really a "safe" buffer and if so, copy
416  * the data from the safe buffer back to the unsafe buffer and free up
417  * the safe buffer.  (basically return things back to the way they
418  * should be)
419  */
420
421 void
422 dma_unmap_single(struct device *dev, dma_addr_t dma_addr, size_t size,
423                         enum dma_data_direction dir)
424 {
425         dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n",
426                 __func__, (void *) dma_addr, size, dir);
427
428         BUG_ON(dir == DMA_NONE);
429
430         unmap_single(dev, dma_addr, size, dir);
431 }
432
433 int
434 dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
435                 enum dma_data_direction dir)
436 {
437         int i;
438
439         dev_dbg(dev, "%s(sg=%p,nents=%d,dir=%x)\n",
440                 __func__, sg, nents, dir);
441
442         BUG_ON(dir == DMA_NONE);
443
444         for (i = 0; i < nents; i++, sg++) {
445                 struct page *page = sg->page;
446                 unsigned int offset = sg->offset;
447                 unsigned int length = sg->length;
448                 void *ptr = page_address(page) + offset;
449
450                 sg->dma_address =
451                         map_single(dev, ptr, length, dir);
452         }
453
454         return nents;
455 }
456
457 void
458 dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,
459                 enum dma_data_direction dir)
460 {
461         int i;
462
463         dev_dbg(dev, "%s(sg=%p,nents=%d,dir=%x)\n",
464                 __func__, sg, nents, dir);
465
466         BUG_ON(dir == DMA_NONE);
467
468         for (i = 0; i < nents; i++, sg++) {
469                 dma_addr_t dma_addr = sg->dma_address;
470                 unsigned int length = sg->length;
471
472                 unmap_single(dev, dma_addr, length, dir);
473         }
474 }
475
476 void
477 dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_addr, size_t size,
478                                 enum dma_data_direction dir)
479 {
480         dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n",
481                 __func__, (void *) dma_addr, size, dir);
482
483         sync_single(dev, dma_addr, size, dir);
484 }
485
486 void
487 dma_sync_single_for_device(struct device *dev, dma_addr_t dma_addr, size_t size,
488                                 enum dma_data_direction dir)
489 {
490         dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n",
491                 __func__, (void *) dma_addr, size, dir);
492
493         sync_single(dev, dma_addr, size, dir);
494 }
495
496 void
497 dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg, int nents,
498                         enum dma_data_direction dir)
499 {
500         int i;
501
502         dev_dbg(dev, "%s(sg=%p,nents=%d,dir=%x)\n",
503                 __func__, sg, nents, dir);
504
505         BUG_ON(dir == DMA_NONE);
506
507         for (i = 0; i < nents; i++, sg++) {
508                 dma_addr_t dma_addr = sg->dma_address;
509                 unsigned int length = sg->length;
510
511                 sync_single(dev, dma_addr, length, dir);
512         }
513 }
514
515 void
516 dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg, int nents,
517                         enum dma_data_direction dir)
518 {
519         int i;
520
521         dev_dbg(dev, "%s(sg=%p,nents=%d,dir=%x)\n",
522                 __func__, sg, nents, dir);
523
524         BUG_ON(dir == DMA_NONE);
525
526         for (i = 0; i < nents; i++, sg++) {
527                 dma_addr_t dma_addr = sg->dma_address;
528                 unsigned int length = sg->length;
529
530                 sync_single(dev, dma_addr, length, dir);
531         }
532 }
533
534 static int
535 dmabounce_init_pool(struct dmabounce_pool *pool, struct device *dev, const char *name,
536                     unsigned long size)
537 {
538         pool->size = size;
539         DO_STATS(pool->allocs = 0);
540         pool->pool = dma_pool_create(name, dev, size,
541                                      0 /* byte alignment */,
542                                      0 /* no page-crossing issues */);
543
544         return pool->pool ? 0 : -ENOMEM;
545 }
546
547 int
548 dmabounce_register_dev(struct device *dev, unsigned long small_buffer_size,
549                         unsigned long large_buffer_size)
550 {
551         struct dmabounce_device_info *device_info;
552         int ret;
553
554         device_info = kmalloc(sizeof(struct dmabounce_device_info), GFP_ATOMIC);
555         if (!device_info) {
556                 printk(KERN_ERR
557                         "Could not allocated dmabounce_device_info for %s",
558                         dev->bus_id);
559                 return -ENOMEM;
560         }
561
562         ret = dmabounce_init_pool(&device_info->small, dev,
563                                   "small_dmabounce_pool", small_buffer_size);
564         if (ret) {
565                 dev_err(dev,
566                         "dmabounce: could not allocate DMA pool for %ld byte objects\n",
567                         small_buffer_size);
568                 goto err_free;
569         }
570
571         if (large_buffer_size) {
572                 ret = dmabounce_init_pool(&device_info->large, dev,
573                                           "large_dmabounce_pool",
574                                           large_buffer_size);
575                 if (ret) {
576                         dev_err(dev,
577                                 "dmabounce: could not allocate DMA pool for %ld byte objects\n",
578                                 large_buffer_size);
579                         goto err_destroy;
580                 }
581         }
582
583         device_info->dev = dev;
584         INIT_LIST_HEAD(&device_info->safe_buffers);
585         rwlock_init(&device_info->lock);
586
587 #ifdef STATS
588         device_info->total_allocs = 0;
589         device_info->map_op_count = 0;
590         device_info->bounce_count = 0;
591         device_info->attr_res = device_create_file(dev, &dev_attr_dmabounce_stats);
592 #endif
593
594         dev->archdata.dmabounce = device_info;
595
596         printk(KERN_INFO "dmabounce: registered device %s on %s bus\n",
597                 dev->bus_id, dev->bus->name);
598
599         return 0;
600
601  err_destroy:
602         dma_pool_destroy(device_info->small.pool);
603  err_free:
604         kfree(device_info);
605         return ret;
606 }
607
608 void
609 dmabounce_unregister_dev(struct device *dev)
610 {
611         struct dmabounce_device_info *device_info = dev->archdata.dmabounce;
612
613         dev->archdata.dmabounce = NULL;
614
615         if (!device_info) {
616                 printk(KERN_WARNING
617                         "%s: Never registered with dmabounce but attempting" \
618                         "to unregister!\n", dev->bus_id);
619                 return;
620         }
621
622         if (!list_empty(&device_info->safe_buffers)) {
623                 printk(KERN_ERR
624                         "%s: Removing from dmabounce with pending buffers!\n",
625                         dev->bus_id);
626                 BUG();
627         }
628
629         if (device_info->small.pool)
630                 dma_pool_destroy(device_info->small.pool);
631         if (device_info->large.pool)
632                 dma_pool_destroy(device_info->large.pool);
633
634 #ifdef STATS
635         if (device_info->attr_res == 0)
636                 device_remove_file(dev, &dev_attr_dmabounce_stats);
637 #endif
638
639         kfree(device_info);
640
641         printk(KERN_INFO "dmabounce: device %s on %s bus unregistered\n",
642                 dev->bus_id, dev->bus->name);
643 }
644
645
646 EXPORT_SYMBOL(dma_map_single);
647 EXPORT_SYMBOL(dma_unmap_single);
648 EXPORT_SYMBOL(dma_map_sg);
649 EXPORT_SYMBOL(dma_unmap_sg);
650 EXPORT_SYMBOL(dma_sync_single_for_cpu);
651 EXPORT_SYMBOL(dma_sync_single_for_device);
652 EXPORT_SYMBOL(dma_sync_sg);
653 EXPORT_SYMBOL(dmabounce_register_dev);
654 EXPORT_SYMBOL(dmabounce_unregister_dev);
655
656 MODULE_AUTHOR("Christopher Hoover <ch@hpl.hp.com>, Deepak Saxena <dsaxena@plexity.net>");
657 MODULE_DESCRIPTION("Special dma_{map/unmap/dma_sync}_* routines for systems with limited DMA windows");
658 MODULE_LICENSE("GPL");