release/src-rt-6.x.4708/linux/linux-2.6.36/arch/arm/common/dmabounce.c

   1 /* Modified by Broadcom Corp. Portions Copyright (c) Broadcom Corp, 2012. */
   2 /*
   3  *  arch/arm/common/dmabounce.c
   4  *
   5  *  Special dma_{map/unmap/dma_sync}_* routines for systems that have
   6  *  limited DMA windows. These functions utilize bounce buffers to
   7  *  copy data to/from buffers located outside the DMA region. This
   8  *  only works for systems in which DMA memory is at the bottom of
   9  *  RAM, the remainder of memory is at the top and the DMA memory
  10  *  can be marked as ZONE_DMA. Anything beyond that such as discontiguous
  11  *  DMA windows will require custom implementations that reserve memory
  12  *  areas at early bootup.
  13  *
  14  *  Original version by Brad Parker (brad@heeltoe.com)
  15  *  Re-written by Christopher Hoover <ch@murgatroid.com>
  16  *  Made generic by Deepak Saxena <dsaxena@plexity.net>
  17  *
  18  *  Copyright (C) 2002 Hewlett Packard Company.
  19  *  Copyright (C) 2004 MontaVista Software, Inc.
  20  *
  21  *  This program is free software; you can redistribute it and/or
  22  *  modify it under the terms of the GNU General Public License
  23  *  version 2 as published by the Free Software Foundation.
  24  */
  25
  26 #include <linux/module.h>
  27 #include <linux/init.h>
  28 #include <linux/slab.h>
  29 #include <linux/page-flags.h>
  30 #include <linux/device.h>
  31 #include <linux/dma-mapping.h>
  32 #include <linux/dmapool.h>
  33 #include <linux/list.h>
  34 #include <linux/scatterlist.h>
  35
  36 #include <asm/cacheflush.h>
  37
  38 #include <typedefs.h>
  39 #include <bcmdefs.h>
  40
  41 #undef STATS
  42
  43 #ifdef STATS
  44 #define DO_STATS(X) do { X ; } while (0)
  45 #else
  46 #define DO_STATS(X) do { } while (0)
  47 #endif
  48
  49 /* ************************************************** */
  50
  51 struct safe_buffer {
  52         struct list_head node;
  53
  54         /* original request */
  55         void            *ptr;
  56         size_t          size;
  57         int             direction;
  58
  59         /* safe buffer info */
  60         struct dmabounce_pool *pool;
  61         void            *safe;
  62         dma_addr_t      safe_dma_addr;
  63 };
  64
  65 struct dmabounce_pool {
  66         unsigned long   size;
  67         struct dma_pool *pool;
  68 #ifdef STATS
  69         unsigned long   allocs;
  70 #endif
  71 };
  72
  73 struct dmabounce_device_info {
  74         struct device *dev;
  75         struct list_head safe_buffers;
  76 #ifdef STATS
  77         unsigned long total_allocs;
  78         unsigned long map_op_count;
  79         unsigned long bounce_count;
  80         int attr_res;
  81 #endif
  82         struct dmabounce_pool   small;
  83         struct dmabounce_pool   large;
  84
  85         rwlock_t lock;
  86 };
  87
  88 #ifdef STATS
  89 static ssize_t dmabounce_show(struct device *dev, struct device_attribute *attr,
  90                               char *buf)
  91 {
  92         struct dmabounce_device_info *device_info = dev->archdata.dmabounce;
  93         return sprintf(buf, "%lu %lu %lu %lu %lu %lu\n",
  94                 device_info->small.allocs,
  95                 device_info->large.allocs,
  96                 device_info->total_allocs - device_info->small.allocs -
  97                         device_info->large.allocs,
  98                 device_info->total_allocs,
  99                 device_info->map_op_count,
 100                 device_info->bounce_count);
 101 }
 102
 103 static DEVICE_ATTR(dmabounce_stats, 0400, dmabounce_show, NULL);
 104 #endif
 105
 106
 107 /* allocate a 'safe' buffer and keep track of it */
 108 static inline struct safe_buffer *
 109 alloc_safe_buffer(struct dmabounce_device_info *device_info, void *ptr,
 110                   size_t size, enum dma_data_direction dir)
 111 {
 112         struct safe_buffer *buf;
 113         struct dmabounce_pool *pool;
 114         struct device *dev = device_info->dev;
 115         unsigned long flags;
 116
 117         dev_dbg(dev, "%s(ptr=%p, size=%d, dir=%d)\n",
 118                 __func__, ptr, size, dir);
 119
 120         if (size <= device_info->small.size) {
 121                 pool = &device_info->small;
 122         } else if (size <= device_info->large.size) {
 123                 pool = &device_info->large;
 124         } else {
 125                 pool = NULL;
 126         }
 127
 128         buf = kmalloc(sizeof(struct safe_buffer), GFP_ATOMIC);
 129         if (buf == NULL) {
 130                 dev_warn(dev, "%s: kmalloc failed\n", __func__);
 131                 return NULL;
 132         }
 133
 134         buf->ptr = ptr;
 135         buf->size = size;
 136         buf->direction = dir;
 137         buf->pool = pool;
 138
 139         if (pool) {
 140                 buf->safe = dma_pool_alloc(pool->pool, GFP_ATOMIC,
 141                                            &buf->safe_dma_addr);
 142         } else {
 143                 buf->safe = dma_alloc_coherent(dev, size, &buf->safe_dma_addr,
 144                                                GFP_ATOMIC);
 145         }
 146
 147         if (buf->safe == NULL) {
 148                 dev_warn(dev,
 149                          "%s: could not alloc dma memory (size=%d)\n",
 150                          __func__, size);
 151                 kfree(buf);
 152                 return NULL;
 153         }
 154
 155 #ifdef STATS
 156         if (pool)
 157                 pool->allocs++;
 158         device_info->total_allocs++;
 159 #endif
 160
 161         write_lock_irqsave(&device_info->lock, flags);
 162         list_add(&buf->node, &device_info->safe_buffers);
 163         write_unlock_irqrestore(&device_info->lock, flags);
 164
 165         return buf;
 166 }
 167
 168 /* determine if a buffer is from our "safe" pool */
 169 static inline struct safe_buffer *
 170 find_safe_buffer(struct dmabounce_device_info *device_info, dma_addr_t safe_dma_addr)
 171 {
 172         struct safe_buffer *b, *rb = NULL;
 173         unsigned long flags;
 174
 175         read_lock_irqsave(&device_info->lock, flags);
 176
 177         list_for_each_entry(b, &device_info->safe_buffers, node)
 178                 if (b->safe_dma_addr == safe_dma_addr) {
 179                         rb = b;
 180                         break;
 181                 }
 182
 183         read_unlock_irqrestore(&device_info->lock, flags);
 184         return rb;
 185 }
 186
 187 static inline void
 188 free_safe_buffer(struct dmabounce_device_info *device_info, struct safe_buffer *buf)
 189 {
 190         unsigned long flags;
 191
 192         dev_dbg(device_info->dev, "%s(buf=%p)\n", __func__, buf);
 193
 194         write_lock_irqsave(&device_info->lock, flags);
 195
 196         list_del(&buf->node);
 197
 198         write_unlock_irqrestore(&device_info->lock, flags);
 199
 200         if (buf->pool)
 201                 dma_pool_free(buf->pool->pool, buf->safe, buf->safe_dma_addr);
 202         else
 203                 dma_free_coherent(device_info->dev, buf->size, buf->safe,
 204                                     buf->safe_dma_addr);
 205
 206         kfree(buf);
 207 }
 208
 209 /* ************************************************** */
 210
 211 static struct safe_buffer *find_safe_buffer_dev(struct device *dev,
 212                 dma_addr_t dma_addr, const char *where)
 213 {
 214         if (!dev || !dev->archdata.dmabounce)
 215                 return NULL;
 216         if (dma_mapping_error(dev, dma_addr)) {
 217                 if (dev)
 218                         dev_err(dev, "Trying to %s invalid mapping\n", where);
 219                 else
 220                         pr_err("unknown device: Trying to %s invalid mapping\n", where);
 221                 return NULL;
 222         }
 223         return find_safe_buffer(dev->archdata.dmabounce, dma_addr);
 224 }
 225
 226 static inline dma_addr_t map_single(struct device *dev, void *ptr, size_t size,
 227                 enum dma_data_direction dir)
 228 {
 229         struct dmabounce_device_info *device_info = dev->archdata.dmabounce;
 230         dma_addr_t dma_addr;
 231         int needs_bounce = 0;
 232
 233         if (device_info)
 234                 DO_STATS ( device_info->map_op_count++ );
 235
 236         dma_addr = virt_to_dma(dev, ptr);
 237
 238         if (dev->dma_mask) {
 239                 unsigned long mask = *dev->dma_mask;
 240                 unsigned long limit;
 241
 242                 limit = (mask + 1) & ~mask;
 243                 if (limit && size > limit) {
 244                         dev_err(dev, "DMA mapping too big (requested %#x "
 245                                 "mask %#Lx)\n", size, *dev->dma_mask);
 246                         return ~0;
 247                 }
 248
 249                 /*
 250                  * Figure out if we need to bounce from the DMA mask.
 251                  */
 252                 needs_bounce = (dma_addr | (dma_addr + size - 1)) & ~mask;
 253         }
 254
 255         if (device_info && (needs_bounce || dma_needs_bounce(dev, dma_addr, size))) {
 256                 struct safe_buffer *buf;
 257
 258                 buf = alloc_safe_buffer(device_info, ptr, size, dir);
 259                 if (buf == 0) {
 260                         dev_err(dev, "%s: unable to map unsafe buffer %p!\n",
 261                                __func__, ptr);
 262                         return 0;
 263                 }
 264
 265                 dev_dbg(dev,
 266                         "%s: unsafe buffer %p (dma=%#x) mapped to %p (dma=%#x)\n",
 267                         __func__, buf->ptr, virt_to_dma(dev, buf->ptr),
 268                         buf->safe, buf->safe_dma_addr);
 269
 270                 if ((dir == DMA_TO_DEVICE) ||
 271                     (dir == DMA_BIDIRECTIONAL)) {
 272                         dev_dbg(dev, "%s: copy unsafe %p to safe %p, size %d\n",
 273                                 __func__, ptr, buf->safe, size);
 274                         memcpy(buf->safe, ptr, size);
 275                 }
 276                 ptr = buf->safe;
 277
 278                 dma_addr = buf->safe_dma_addr;
 279         } else {
 280                 /*
 281                  * We don't need to sync the DMA buffer since
 282                  * it was allocated via the coherent allocators.
 283                  */
 284                 __dma_single_cpu_to_dev(ptr, size, dir);
 285         }
 286
 287         return dma_addr;
 288 }
 289
 290 static inline void unmap_single(struct device *dev, dma_addr_t dma_addr,
 291                 size_t size, enum dma_data_direction dir)
 292 {
 293         struct safe_buffer *buf = find_safe_buffer_dev(dev, dma_addr, "unmap");
 294
 295         if (buf) {
 296                 BUG_ON(buf->size != size);
 297                 BUG_ON(buf->direction != dir);
 298
 299                 dev_dbg(dev,
 300                         "%s: unsafe buffer %p (dma=%#x) mapped to %p (dma=%#x)\n",
 301                         __func__, buf->ptr, virt_to_dma(dev, buf->ptr),
 302                         buf->safe, buf->safe_dma_addr);
 303
 304                 DO_STATS(dev->archdata.dmabounce->bounce_count++);
 305
 306                 if (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL) {
 307                         void *ptr = buf->ptr;
 308
 309                         dev_dbg(dev,
 310                                 "%s: copy back safe %p to unsafe %p size %d\n",
 311                                 __func__, buf->safe, ptr, size);
 312                         memcpy(ptr, buf->safe, size);
 313
 314                         /*
 315                          * Since we may have written to a page cache page,
 316                          * we need to ensure that the data will be coherent
 317                          * with user mappings.
 318                          */
 319                         __cpuc_flush_dcache_area(ptr, size);
 320                 }
 321                 free_safe_buffer(dev->archdata.dmabounce, buf);
 322         } else {
 323                 __dma_single_dev_to_cpu(dma_to_virt(dev, dma_addr), size, dir);
 324         }
 325 }
 326
 327 /* ************************************************** */
 328
 329 /*
 330  * see if a buffer address is in an 'unsafe' range.  if it is
 331  * allocate a 'safe' buffer and copy the unsafe buffer into it.
 332  * substitute the safe buffer for the unsafe one.
 333  * (basically move the buffer from an unsafe area to a safe one)
 334  */
 335 dma_addr_t BCMFASTPATH dma_map_single(struct device *dev, void *ptr, size_t size,
 336                 enum dma_data_direction dir)
 337 {
 338         dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n",
 339                 __func__, ptr, size, dir);
 340
 341         BUG_ON(!valid_dma_direction(dir));
 342
 343         return map_single(dev, ptr, size, dir);
 344 }
 345 EXPORT_SYMBOL(dma_map_single);
 346
 347 /*
 348  * see if a mapped address was really a "safe" buffer and if so, copy
 349  * the data from the safe buffer back to the unsafe buffer and free up
 350  * the safe buffer.  (basically return things back to the way they
 351  * should be)
 352  */
 353 void BCMFASTPATH dma_unmap_single(struct device *dev, dma_addr_t dma_addr, size_t size,
 354                 enum dma_data_direction dir)
 355 {
 356         dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n",
 357                 __func__, (void *) dma_addr, size, dir);
 358
 359         unmap_single(dev, dma_addr, size, dir);
 360 }
 361 EXPORT_SYMBOL(dma_unmap_single);
 362
 363 dma_addr_t dma_map_page(struct device *dev, struct page *page,
 364                 unsigned long offset, size_t size, enum dma_data_direction dir)
 365 {
 366         dev_dbg(dev, "%s(page=%p,off=%#lx,size=%zx,dir=%x)\n",
 367                 __func__, page, offset, size, dir);
 368
 369         BUG_ON(!valid_dma_direction(dir));
 370
 371         if (PageHighMem(page)) {
 372                 dev_err(dev, "DMA buffer bouncing of HIGHMEM pages "
 373                              "is not supported\n");
 374                 return ~0;
 375         }
 376
 377         return map_single(dev, page_address(page) + offset, size, dir);
 378 }
 379 EXPORT_SYMBOL(dma_map_page);
 380
 381 /*
 382  * see if a mapped address was really a "safe" buffer and if so, copy
 383  * the data from the safe buffer back to the unsafe buffer and free up
 384  * the safe buffer.  (basically return things back to the way they
 385  * should be)
 386  */
 387 void dma_unmap_page(struct device *dev, dma_addr_t dma_addr, size_t size,
 388                 enum dma_data_direction dir)
 389 {
 390         dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n",
 391                 __func__, (void *) dma_addr, size, dir);
 392
 393         unmap_single(dev, dma_addr, size, dir);
 394 }
 395 EXPORT_SYMBOL(dma_unmap_page);
 396
 397 int dmabounce_sync_for_cpu(struct device *dev, dma_addr_t addr,
 398                 unsigned long off, size_t sz, enum dma_data_direction dir)
 399 {
 400         struct safe_buffer *buf;
 401
 402         dev_dbg(dev, "%s(dma=%#x,off=%#lx,sz=%zx,dir=%x)\n",
 403                 __func__, addr, off, sz, dir);
 404
 405         buf = find_safe_buffer_dev(dev, addr, __func__);
 406         if (!buf)
 407                 return 1;
 408
 409         BUG_ON(buf->direction != dir);
 410
 411         dev_dbg(dev, "%s: unsafe buffer %p (dma=%#x) mapped to %p (dma=%#x)\n",
 412                 __func__, buf->ptr, virt_to_dma(dev, buf->ptr),
 413                 buf->safe, buf->safe_dma_addr);
 414
 415         DO_STATS(dev->archdata.dmabounce->bounce_count++);
 416
 417         if (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL) {
 418                 dev_dbg(dev, "%s: copy back safe %p to unsafe %p size %d\n",
 419                         __func__, buf->safe + off, buf->ptr + off, sz);
 420                 memcpy(buf->ptr + off, buf->safe + off, sz);
 421         }
 422         return 0;
 423 }
 424 EXPORT_SYMBOL(dmabounce_sync_for_cpu);
 425
 426 int dmabounce_sync_for_device(struct device *dev, dma_addr_t addr,
 427                 unsigned long off, size_t sz, enum dma_data_direction dir)
 428 {
 429         struct safe_buffer *buf;
 430
 431         dev_dbg(dev, "%s(dma=%#x,off=%#lx,sz=%zx,dir=%x)\n",
 432                 __func__, addr, off, sz, dir);
 433
 434         buf = find_safe_buffer_dev(dev, addr, __func__);
 435         if (!buf)
 436                 return 1;
 437
 438         BUG_ON(buf->direction != dir);
 439
 440         dev_dbg(dev, "%s: unsafe buffer %p (dma=%#x) mapped to %p (dma=%#x)\n",
 441                 __func__, buf->ptr, virt_to_dma(dev, buf->ptr),
 442                 buf->safe, buf->safe_dma_addr);
 443
 444         DO_STATS(dev->archdata.dmabounce->bounce_count++);
 445
 446         if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL) {
 447                 dev_dbg(dev, "%s: copy out unsafe %p to safe %p, size %d\n",
 448                         __func__,buf->ptr + off, buf->safe + off, sz);
 449                 memcpy(buf->safe + off, buf->ptr + off, sz);
 450         }
 451         return 0;
 452 }
 453 EXPORT_SYMBOL(dmabounce_sync_for_device);
 454
 455 static int dmabounce_init_pool(struct dmabounce_pool *pool, struct device *dev,
 456                 const char *name, unsigned long size)
 457 {
 458         pool->size = size;
 459         DO_STATS(pool->allocs = 0);
 460         pool->pool = dma_pool_create(name, dev, size,
 461                                      0 /* byte alignment */,
 462                                      0 /* no page-crossing issues */);
 463
 464         return pool->pool ? 0 : -ENOMEM;
 465 }
 466
 467 int dmabounce_register_dev(struct device *dev, unsigned long small_buffer_size,
 468                 unsigned long large_buffer_size)
 469 {
 470         struct dmabounce_device_info *device_info;
 471         int ret;
 472
 473         device_info = kmalloc(sizeof(struct dmabounce_device_info), GFP_ATOMIC);
 474         if (!device_info) {
 475                 dev_err(dev,
 476                         "Could not allocated dmabounce_device_info\n");
 477                 return -ENOMEM;
 478         }
 479
 480         ret = dmabounce_init_pool(&device_info->small, dev,
 481                                   "small_dmabounce_pool", small_buffer_size);
 482         if (ret) {
 483                 dev_err(dev,
 484                         "dmabounce: could not allocate DMA pool for %ld byte objects\n",
 485                         small_buffer_size);
 486                 goto err_free;
 487         }
 488
 489         if (large_buffer_size) {
 490                 ret = dmabounce_init_pool(&device_info->large, dev,
 491                                           "large_dmabounce_pool",
 492                                           large_buffer_size);
 493                 if (ret) {
 494                         dev_err(dev,
 495                                 "dmabounce: could not allocate DMA pool for %ld byte objects\n",
 496                                 large_buffer_size);
 497                         goto err_destroy;
 498                 }
 499         }
 500
 501         device_info->dev = dev;
 502         INIT_LIST_HEAD(&device_info->safe_buffers);
 503         rwlock_init(&device_info->lock);
 504
 505 #ifdef STATS
 506         device_info->total_allocs = 0;
 507         device_info->map_op_count = 0;
 508         device_info->bounce_count = 0;
 509         device_info->attr_res = device_create_file(dev, &dev_attr_dmabounce_stats);
 510 #endif
 511
 512         dev->archdata.dmabounce = device_info;
 513
 514         dev_info(dev, "dmabounce: registered device\n");
 515
 516         return 0;
 517
 518  err_destroy:
 519         dma_pool_destroy(device_info->small.pool);
 520  err_free:
 521         kfree(device_info);
 522         return ret;
 523 }
 524 EXPORT_SYMBOL(dmabounce_register_dev);
 525
 526 void dmabounce_unregister_dev(struct device *dev)
 527 {
 528         struct dmabounce_device_info *device_info = dev->archdata.dmabounce;
 529
 530         dev->archdata.dmabounce = NULL;
 531
 532         if (!device_info) {
 533                 dev_warn(dev,
 534                          "Never registered with dmabounce but attempting"
 535                          "to unregister!\n");
 536                 return;
 537         }
 538
 539         if (!list_empty(&device_info->safe_buffers)) {
 540                 dev_err(dev,
 541                         "Removing from dmabounce with pending buffers!\n");
 542                 BUG();
 543         }
 544
 545         if (device_info->small.pool)
 546                 dma_pool_destroy(device_info->small.pool);
 547         if (device_info->large.pool)
 548                 dma_pool_destroy(device_info->large.pool);
 549
 550 #ifdef STATS
 551         if (device_info->attr_res == 0)
 552                 device_remove_file(dev, &dev_attr_dmabounce_stats);
 553 #endif
 554
 555         kfree(device_info);
 556
 557         dev_info(dev, "dmabounce: device unregistered\n");
 558 }
 559 EXPORT_SYMBOL(dmabounce_unregister_dev);
 560
 561 MODULE_AUTHOR("Christopher Hoover <ch@hpl.hp.com>, Deepak Saxena <dsaxena@plexity.net>");
 562 MODULE_DESCRIPTION("Special dma_{map/unmap/dma_sync}_* routines for systems with limited DMA windows");
 563 MODULE_LICENSE("GPL");