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1 | /* | |
2 | * DMA Pool allocator | |
3 | * | |
4 | * Copyright 2001 David Brownell | |
5 | * Copyright 2007 Intel Corporation | |
6 | * Author: Matthew Wilcox <willy@linux.intel.com> | |
7 | * | |
8 | * This software may be redistributed and/or modified under the terms of | |
9 | * the GNU General Public License ("GPL") version 2 as published by the | |
10 | * Free Software Foundation. | |
11 | * | |
12 | * This allocator returns small blocks of a given size which are DMA-able by | |
13 | * the given device. It uses the dma_alloc_coherent page allocator to get | |
14 | * new pages, then splits them up into blocks of the required size. | |
15 | * Many older drivers still have their own code to do this. | |
16 | * | |
17 | * The current design of this allocator is fairly simple. The pool is | |
18 | * represented by the 'struct dma_pool' which keeps a doubly-linked list of | |
19 | * allocated pages. Each page in the page_list is split into blocks of at | |
20 | * least 'size' bytes. Free blocks are tracked in an unsorted singly-linked | |
21 | * list of free blocks within the page. Used blocks aren't tracked, but we | |
22 | * keep a count of how many are currently allocated from each page. | |
23 | */ | |
24 | ||
25 | #include <linux/device.h> | |
26 | #include <linux/dma-mapping.h> | |
27 | #include <linux/dmapool.h> | |
28 | #include <linux/kernel.h> | |
29 | #include <linux/list.h> | |
30 | #include <linux/export.h> | |
31 | #include <linux/mutex.h> | |
32 | #include <linux/poison.h> | |
33 | #include <linux/sched.h> | |
34 | #include <linux/slab.h> | |
35 | #include <linux/stat.h> | |
36 | #include <linux/spinlock.h> | |
37 | #include <linux/string.h> | |
38 | #include <linux/types.h> | |
39 | #include <linux/wait.h> | |
40 | ||
41 | #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB_DEBUG_ON) | |
42 | #define DMAPOOL_DEBUG 1 | |
43 | #endif | |
44 | ||
45 | struct dma_pool { /* the pool */ | |
46 | struct list_head page_list; | |
47 | spinlock_t lock; | |
48 | size_t size; | |
49 | struct device *dev; | |
50 | size_t allocation; | |
51 | size_t boundary; | |
52 | char name[32]; | |
53 | struct list_head pools; | |
54 | }; | |
55 | ||
56 | struct dma_page { /* cacheable header for 'allocation' bytes */ | |
57 | struct list_head page_list; | |
58 | void *vaddr; | |
59 | dma_addr_t dma; | |
60 | unsigned int in_use; | |
61 | unsigned int offset; | |
62 | }; | |
63 | ||
64 | static DEFINE_MUTEX(pools_lock); | |
65 | static DEFINE_MUTEX(pools_reg_lock); | |
66 | ||
67 | static ssize_t | |
68 | show_pools(struct device *dev, struct device_attribute *attr, char *buf) | |
69 | { | |
70 | unsigned temp; | |
71 | unsigned size; | |
72 | char *next; | |
73 | struct dma_page *page; | |
74 | struct dma_pool *pool; | |
75 | ||
76 | next = buf; | |
77 | size = PAGE_SIZE; | |
78 | ||
79 | temp = scnprintf(next, size, "poolinfo - 0.1\n"); | |
80 | size -= temp; | |
81 | next += temp; | |
82 | ||
83 | mutex_lock(&pools_lock); | |
84 | list_for_each_entry(pool, &dev->dma_pools, pools) { | |
85 | unsigned pages = 0; | |
86 | unsigned blocks = 0; | |
87 | ||
88 | spin_lock_irq(&pool->lock); | |
89 | list_for_each_entry(page, &pool->page_list, page_list) { | |
90 | pages++; | |
91 | blocks += page->in_use; | |
92 | } | |
93 | spin_unlock_irq(&pool->lock); | |
94 | ||
95 | /* per-pool info, no real statistics yet */ | |
96 | temp = scnprintf(next, size, "%-16s %4u %4Zu %4Zu %2u\n", | |
97 | pool->name, blocks, | |
98 | pages * (pool->allocation / pool->size), | |
99 | pool->size, pages); | |
100 | size -= temp; | |
101 | next += temp; | |
102 | } | |
103 | mutex_unlock(&pools_lock); | |
104 | ||
105 | return PAGE_SIZE - size; | |
106 | } | |
107 | ||
108 | static DEVICE_ATTR(pools, S_IRUGO, show_pools, NULL); | |
109 | ||
110 | /** | |
111 | * dma_pool_create - Creates a pool of consistent memory blocks, for dma. | |
112 | * @name: name of pool, for diagnostics | |
113 | * @dev: device that will be doing the DMA | |
114 | * @size: size of the blocks in this pool. | |
115 | * @align: alignment requirement for blocks; must be a power of two | |
116 | * @boundary: returned blocks won't cross this power of two boundary | |
117 | * Context: !in_interrupt() | |
118 | * | |
119 | * Returns a dma allocation pool with the requested characteristics, or | |
120 | * null if one can't be created. Given one of these pools, dma_pool_alloc() | |
121 | * may be used to allocate memory. Such memory will all have "consistent" | |
122 | * DMA mappings, accessible by the device and its driver without using | |
123 | * cache flushing primitives. The actual size of blocks allocated may be | |
124 | * larger than requested because of alignment. | |
125 | * | |
126 | * If @boundary is nonzero, objects returned from dma_pool_alloc() won't | |
127 | * cross that size boundary. This is useful for devices which have | |
128 | * addressing restrictions on individual DMA transfers, such as not crossing | |
129 | * boundaries of 4KBytes. | |
130 | */ | |
131 | struct dma_pool *dma_pool_create(const char *name, struct device *dev, | |
132 | size_t size, size_t align, size_t boundary) | |
133 | { | |
134 | struct dma_pool *retval; | |
135 | size_t allocation; | |
136 | bool empty = false; | |
137 | ||
138 | if (align == 0) | |
139 | align = 1; | |
140 | else if (align & (align - 1)) | |
141 | return NULL; | |
142 | ||
143 | if (size == 0) | |
144 | return NULL; | |
145 | else if (size < 4) | |
146 | size = 4; | |
147 | ||
148 | if ((size % align) != 0) | |
149 | size = ALIGN(size, align); | |
150 | ||
151 | allocation = max_t(size_t, size, PAGE_SIZE); | |
152 | ||
153 | if (!boundary) | |
154 | boundary = allocation; | |
155 | else if ((boundary < size) || (boundary & (boundary - 1))) | |
156 | return NULL; | |
157 | ||
158 | retval = kmalloc_node(sizeof(*retval), GFP_KERNEL, dev_to_node(dev)); | |
159 | if (!retval) | |
160 | return retval; | |
161 | ||
162 | strlcpy(retval->name, name, sizeof(retval->name)); | |
163 | ||
164 | retval->dev = dev; | |
165 | ||
166 | INIT_LIST_HEAD(&retval->page_list); | |
167 | spin_lock_init(&retval->lock); | |
168 | retval->size = size; | |
169 | retval->boundary = boundary; | |
170 | retval->allocation = allocation; | |
171 | ||
172 | INIT_LIST_HEAD(&retval->pools); | |
173 | ||
174 | /* | |
175 | * pools_lock ensures that the ->dma_pools list does not get corrupted. | |
176 | * pools_reg_lock ensures that there is not a race between | |
177 | * dma_pool_create() and dma_pool_destroy() or within dma_pool_create() | |
178 | * when the first invocation of dma_pool_create() failed on | |
179 | * device_create_file() and the second assumes that it has been done (I | |
180 | * know it is a short window). | |
181 | */ | |
182 | mutex_lock(&pools_reg_lock); | |
183 | mutex_lock(&pools_lock); | |
184 | if (list_empty(&dev->dma_pools)) | |
185 | empty = true; | |
186 | list_add(&retval->pools, &dev->dma_pools); | |
187 | mutex_unlock(&pools_lock); | |
188 | if (empty) { | |
189 | int err; | |
190 | ||
191 | err = device_create_file(dev, &dev_attr_pools); | |
192 | if (err) { | |
193 | mutex_lock(&pools_lock); | |
194 | list_del(&retval->pools); | |
195 | mutex_unlock(&pools_lock); | |
196 | mutex_unlock(&pools_reg_lock); | |
197 | kfree(retval); | |
198 | return NULL; | |
199 | } | |
200 | } | |
201 | mutex_unlock(&pools_reg_lock); | |
202 | return retval; | |
203 | } | |
204 | EXPORT_SYMBOL(dma_pool_create); | |
205 | ||
206 | static void pool_initialise_page(struct dma_pool *pool, struct dma_page *page) | |
207 | { | |
208 | unsigned int offset = 0; | |
209 | unsigned int next_boundary = pool->boundary; | |
210 | ||
211 | do { | |
212 | unsigned int next = offset + pool->size; | |
213 | if (unlikely((next + pool->size) >= next_boundary)) { | |
214 | next = next_boundary; | |
215 | next_boundary += pool->boundary; | |
216 | } | |
217 | *(int *)(page->vaddr + offset) = next; | |
218 | offset = next; | |
219 | } while (offset < pool->allocation); | |
220 | } | |
221 | ||
222 | static struct dma_page *pool_alloc_page(struct dma_pool *pool, gfp_t mem_flags) | |
223 | { | |
224 | struct dma_page *page; | |
225 | ||
226 | page = kmalloc(sizeof(*page), mem_flags); | |
227 | if (!page) | |
228 | return NULL; | |
229 | page->vaddr = dma_alloc_coherent(pool->dev, pool->allocation, | |
230 | &page->dma, mem_flags); | |
231 | if (page->vaddr) { | |
232 | #ifdef DMAPOOL_DEBUG | |
233 | memset(page->vaddr, POOL_POISON_FREED, pool->allocation); | |
234 | #endif | |
235 | pool_initialise_page(pool, page); | |
236 | page->in_use = 0; | |
237 | page->offset = 0; | |
238 | } else { | |
239 | kfree(page); | |
240 | page = NULL; | |
241 | } | |
242 | return page; | |
243 | } | |
244 | ||
245 | static inline bool is_page_busy(struct dma_page *page) | |
246 | { | |
247 | return page->in_use != 0; | |
248 | } | |
249 | ||
250 | static void pool_free_page(struct dma_pool *pool, struct dma_page *page) | |
251 | { | |
252 | dma_addr_t dma = page->dma; | |
253 | ||
254 | #ifdef DMAPOOL_DEBUG | |
255 | memset(page->vaddr, POOL_POISON_FREED, pool->allocation); | |
256 | #endif | |
257 | dma_free_coherent(pool->dev, pool->allocation, page->vaddr, dma); | |
258 | list_del(&page->page_list); | |
259 | kfree(page); | |
260 | } | |
261 | ||
262 | /** | |
263 | * dma_pool_destroy - destroys a pool of dma memory blocks. | |
264 | * @pool: dma pool that will be destroyed | |
265 | * Context: !in_interrupt() | |
266 | * | |
267 | * Caller guarantees that no more memory from the pool is in use, | |
268 | * and that nothing will try to use the pool after this call. | |
269 | */ | |
270 | void dma_pool_destroy(struct dma_pool *pool) | |
271 | { | |
272 | bool empty = false; | |
273 | ||
274 | if (unlikely(!pool)) | |
275 | return; | |
276 | ||
277 | mutex_lock(&pools_reg_lock); | |
278 | mutex_lock(&pools_lock); | |
279 | list_del(&pool->pools); | |
280 | if (pool->dev && list_empty(&pool->dev->dma_pools)) | |
281 | empty = true; | |
282 | mutex_unlock(&pools_lock); | |
283 | if (empty) | |
284 | device_remove_file(pool->dev, &dev_attr_pools); | |
285 | mutex_unlock(&pools_reg_lock); | |
286 | ||
287 | while (!list_empty(&pool->page_list)) { | |
288 | struct dma_page *page; | |
289 | page = list_entry(pool->page_list.next, | |
290 | struct dma_page, page_list); | |
291 | if (is_page_busy(page)) { | |
292 | if (pool->dev) | |
293 | dev_err(pool->dev, | |
294 | "dma_pool_destroy %s, %p busy\n", | |
295 | pool->name, page->vaddr); | |
296 | else | |
297 | pr_err("dma_pool_destroy %s, %p busy\n", | |
298 | pool->name, page->vaddr); | |
299 | /* leak the still-in-use consistent memory */ | |
300 | list_del(&page->page_list); | |
301 | kfree(page); | |
302 | } else | |
303 | pool_free_page(pool, page); | |
304 | } | |
305 | ||
306 | kfree(pool); | |
307 | } | |
308 | EXPORT_SYMBOL(dma_pool_destroy); | |
309 | ||
310 | /** | |
311 | * dma_pool_alloc - get a block of consistent memory | |
312 | * @pool: dma pool that will produce the block | |
313 | * @mem_flags: GFP_* bitmask | |
314 | * @handle: pointer to dma address of block | |
315 | * | |
316 | * This returns the kernel virtual address of a currently unused block, | |
317 | * and reports its dma address through the handle. | |
318 | * If such a memory block can't be allocated, %NULL is returned. | |
319 | */ | |
320 | void *dma_pool_alloc(struct dma_pool *pool, gfp_t mem_flags, | |
321 | dma_addr_t *handle) | |
322 | { | |
323 | unsigned long flags; | |
324 | struct dma_page *page; | |
325 | size_t offset; | |
326 | void *retval; | |
327 | ||
328 | might_sleep_if(gfpflags_allow_blocking(mem_flags)); | |
329 | ||
330 | spin_lock_irqsave(&pool->lock, flags); | |
331 | list_for_each_entry(page, &pool->page_list, page_list) { | |
332 | if (page->offset < pool->allocation) | |
333 | goto ready; | |
334 | } | |
335 | ||
336 | /* pool_alloc_page() might sleep, so temporarily drop &pool->lock */ | |
337 | spin_unlock_irqrestore(&pool->lock, flags); | |
338 | ||
339 | page = pool_alloc_page(pool, mem_flags & (~__GFP_ZERO)); | |
340 | if (!page) | |
341 | return NULL; | |
342 | ||
343 | spin_lock_irqsave(&pool->lock, flags); | |
344 | ||
345 | list_add(&page->page_list, &pool->page_list); | |
346 | ready: | |
347 | page->in_use++; | |
348 | offset = page->offset; | |
349 | page->offset = *(int *)(page->vaddr + offset); | |
350 | retval = offset + page->vaddr; | |
351 | *handle = offset + page->dma; | |
352 | #ifdef DMAPOOL_DEBUG | |
353 | { | |
354 | int i; | |
355 | u8 *data = retval; | |
356 | /* page->offset is stored in first 4 bytes */ | |
357 | for (i = sizeof(page->offset); i < pool->size; i++) { | |
358 | if (data[i] == POOL_POISON_FREED) | |
359 | continue; | |
360 | if (pool->dev) | |
361 | dev_err(pool->dev, | |
362 | "dma_pool_alloc %s, %p (corrupted)\n", | |
363 | pool->name, retval); | |
364 | else | |
365 | pr_err("dma_pool_alloc %s, %p (corrupted)\n", | |
366 | pool->name, retval); | |
367 | ||
368 | /* | |
369 | * Dump the first 4 bytes even if they are not | |
370 | * POOL_POISON_FREED | |
371 | */ | |
372 | print_hex_dump(KERN_ERR, "", DUMP_PREFIX_OFFSET, 16, 1, | |
373 | data, pool->size, 1); | |
374 | break; | |
375 | } | |
376 | } | |
377 | if (!(mem_flags & __GFP_ZERO)) | |
378 | memset(retval, POOL_POISON_ALLOCATED, pool->size); | |
379 | #endif | |
380 | spin_unlock_irqrestore(&pool->lock, flags); | |
381 | ||
382 | if (mem_flags & __GFP_ZERO) | |
383 | memset(retval, 0, pool->size); | |
384 | ||
385 | return retval; | |
386 | } | |
387 | EXPORT_SYMBOL(dma_pool_alloc); | |
388 | ||
389 | static struct dma_page *pool_find_page(struct dma_pool *pool, dma_addr_t dma) | |
390 | { | |
391 | struct dma_page *page; | |
392 | ||
393 | list_for_each_entry(page, &pool->page_list, page_list) { | |
394 | if (dma < page->dma) | |
395 | continue; | |
396 | if ((dma - page->dma) < pool->allocation) | |
397 | return page; | |
398 | } | |
399 | return NULL; | |
400 | } | |
401 | ||
402 | /** | |
403 | * dma_pool_free - put block back into dma pool | |
404 | * @pool: the dma pool holding the block | |
405 | * @vaddr: virtual address of block | |
406 | * @dma: dma address of block | |
407 | * | |
408 | * Caller promises neither device nor driver will again touch this block | |
409 | * unless it is first re-allocated. | |
410 | */ | |
411 | void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma) | |
412 | { | |
413 | struct dma_page *page; | |
414 | unsigned long flags; | |
415 | unsigned int offset; | |
416 | ||
417 | spin_lock_irqsave(&pool->lock, flags); | |
418 | page = pool_find_page(pool, dma); | |
419 | if (!page) { | |
420 | spin_unlock_irqrestore(&pool->lock, flags); | |
421 | if (pool->dev) | |
422 | dev_err(pool->dev, | |
423 | "dma_pool_free %s, %p/%lx (bad dma)\n", | |
424 | pool->name, vaddr, (unsigned long)dma); | |
425 | else | |
426 | pr_err("dma_pool_free %s, %p/%lx (bad dma)\n", | |
427 | pool->name, vaddr, (unsigned long)dma); | |
428 | return; | |
429 | } | |
430 | ||
431 | offset = vaddr - page->vaddr; | |
432 | #ifdef DMAPOOL_DEBUG | |
433 | if ((dma - page->dma) != offset) { | |
434 | spin_unlock_irqrestore(&pool->lock, flags); | |
435 | if (pool->dev) | |
436 | dev_err(pool->dev, | |
437 | "dma_pool_free %s, %p (bad vaddr)/%Lx\n", | |
438 | pool->name, vaddr, (unsigned long long)dma); | |
439 | else | |
440 | pr_err("dma_pool_free %s, %p (bad vaddr)/%Lx\n", | |
441 | pool->name, vaddr, (unsigned long long)dma); | |
442 | return; | |
443 | } | |
444 | { | |
445 | unsigned int chain = page->offset; | |
446 | while (chain < pool->allocation) { | |
447 | if (chain != offset) { | |
448 | chain = *(int *)(page->vaddr + chain); | |
449 | continue; | |
450 | } | |
451 | spin_unlock_irqrestore(&pool->lock, flags); | |
452 | if (pool->dev) | |
453 | dev_err(pool->dev, "dma_pool_free %s, dma %Lx already free\n", | |
454 | pool->name, (unsigned long long)dma); | |
455 | else | |
456 | pr_err("dma_pool_free %s, dma %Lx already free\n", | |
457 | pool->name, (unsigned long long)dma); | |
458 | return; | |
459 | } | |
460 | } | |
461 | memset(vaddr, POOL_POISON_FREED, pool->size); | |
462 | #endif | |
463 | ||
464 | page->in_use--; | |
465 | *(int *)vaddr = page->offset; | |
466 | page->offset = offset; | |
467 | /* | |
468 | * Resist a temptation to do | |
469 | * if (!is_page_busy(page)) pool_free_page(pool, page); | |
470 | * Better have a few empty pages hang around. | |
471 | */ | |
472 | spin_unlock_irqrestore(&pool->lock, flags); | |
473 | } | |
474 | EXPORT_SYMBOL(dma_pool_free); | |
475 | ||
476 | /* | |
477 | * Managed DMA pool | |
478 | */ | |
479 | static void dmam_pool_release(struct device *dev, void *res) | |
480 | { | |
481 | struct dma_pool *pool = *(struct dma_pool **)res; | |
482 | ||
483 | dma_pool_destroy(pool); | |
484 | } | |
485 | ||
486 | static int dmam_pool_match(struct device *dev, void *res, void *match_data) | |
487 | { | |
488 | return *(struct dma_pool **)res == match_data; | |
489 | } | |
490 | ||
491 | /** | |
492 | * dmam_pool_create - Managed dma_pool_create() | |
493 | * @name: name of pool, for diagnostics | |
494 | * @dev: device that will be doing the DMA | |
495 | * @size: size of the blocks in this pool. | |
496 | * @align: alignment requirement for blocks; must be a power of two | |
497 | * @allocation: returned blocks won't cross this boundary (or zero) | |
498 | * | |
499 | * Managed dma_pool_create(). DMA pool created with this function is | |
500 | * automatically destroyed on driver detach. | |
501 | */ | |
502 | struct dma_pool *dmam_pool_create(const char *name, struct device *dev, | |
503 | size_t size, size_t align, size_t allocation) | |
504 | { | |
505 | struct dma_pool **ptr, *pool; | |
506 | ||
507 | ptr = devres_alloc(dmam_pool_release, sizeof(*ptr), GFP_KERNEL); | |
508 | if (!ptr) | |
509 | return NULL; | |
510 | ||
511 | pool = *ptr = dma_pool_create(name, dev, size, align, allocation); | |
512 | if (pool) | |
513 | devres_add(dev, ptr); | |
514 | else | |
515 | devres_free(ptr); | |
516 | ||
517 | return pool; | |
518 | } | |
519 | EXPORT_SYMBOL(dmam_pool_create); | |
520 | ||
521 | /** | |
522 | * dmam_pool_destroy - Managed dma_pool_destroy() | |
523 | * @pool: dma pool that will be destroyed | |
524 | * | |
525 | * Managed dma_pool_destroy(). | |
526 | */ | |
527 | void dmam_pool_destroy(struct dma_pool *pool) | |
528 | { | |
529 | struct device *dev = pool->dev; | |
530 | ||
531 | WARN_ON(devres_release(dev, dmam_pool_release, dmam_pool_match, pool)); | |
532 | } | |
533 | EXPORT_SYMBOL(dmam_pool_destroy); |