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1 | // SPDX-License-Identifier: GPL-2.0-only | |
2 | /* | |
3 | * DMA Pool allocator | |
4 | * | |
5 | * Copyright 2001 David Brownell | |
6 | * Copyright 2007 Intel Corporation | |
7 | * Author: Matthew Wilcox <willy@linux.intel.com> | |
8 | * | |
9 | * This allocator returns small blocks of a given size which are DMA-able by | |
10 | * the given device. It uses the dma_alloc_coherent page allocator to get | |
11 | * new pages, then splits them up into blocks of the required size. | |
12 | * Many older drivers still have their own code to do this. | |
13 | * | |
14 | * The current design of this allocator is fairly simple. The pool is | |
15 | * represented by the 'struct dma_pool' which keeps a doubly-linked list of | |
16 | * allocated pages. Each page in the page_list is split into blocks of at | |
17 | * least 'size' bytes. Free blocks are tracked in an unsorted singly-linked | |
18 | * list of free blocks within the page. Used blocks aren't tracked, but we | |
19 | * keep a count of how many are currently allocated from each page. | |
20 | */ | |
21 | ||
22 | #include <linux/device.h> | |
23 | #include <linux/dma-mapping.h> | |
24 | #include <linux/dmapool.h> | |
25 | #include <linux/kernel.h> | |
26 | #include <linux/list.h> | |
27 | #include <linux/export.h> | |
28 | #include <linux/mutex.h> | |
29 | #include <linux/poison.h> | |
30 | #include <linux/sched.h> | |
31 | #include <linux/slab.h> | |
32 | #include <linux/stat.h> | |
33 | #include <linux/spinlock.h> | |
34 | #include <linux/string.h> | |
35 | #include <linux/types.h> | |
36 | #include <linux/wait.h> | |
37 | ||
38 | #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB_DEBUG_ON) | |
39 | #define DMAPOOL_DEBUG 1 | |
40 | #endif | |
41 | ||
42 | struct dma_pool { /* the pool */ | |
43 | struct list_head page_list; | |
44 | spinlock_t lock; | |
45 | size_t size; | |
46 | struct device *dev; | |
47 | size_t allocation; | |
48 | size_t boundary; | |
49 | char name[32]; | |
50 | struct list_head pools; | |
51 | }; | |
52 | ||
53 | struct dma_page { /* cacheable header for 'allocation' bytes */ | |
54 | struct list_head page_list; | |
55 | void *vaddr; | |
56 | dma_addr_t dma; | |
57 | unsigned int in_use; | |
58 | unsigned int offset; | |
59 | }; | |
60 | ||
61 | static DEFINE_MUTEX(pools_lock); | |
62 | static DEFINE_MUTEX(pools_reg_lock); | |
63 | ||
64 | static ssize_t | |
65 | show_pools(struct device *dev, struct device_attribute *attr, char *buf) | |
66 | { | |
67 | unsigned temp; | |
68 | unsigned size; | |
69 | char *next; | |
70 | struct dma_page *page; | |
71 | struct dma_pool *pool; | |
72 | ||
73 | next = buf; | |
74 | size = PAGE_SIZE; | |
75 | ||
76 | temp = scnprintf(next, size, "poolinfo - 0.1\n"); | |
77 | size -= temp; | |
78 | next += temp; | |
79 | ||
80 | mutex_lock(&pools_lock); | |
81 | list_for_each_entry(pool, &dev->dma_pools, pools) { | |
82 | unsigned pages = 0; | |
83 | unsigned blocks = 0; | |
84 | ||
85 | spin_lock_irq(&pool->lock); | |
86 | list_for_each_entry(page, &pool->page_list, page_list) { | |
87 | pages++; | |
88 | blocks += page->in_use; | |
89 | } | |
90 | spin_unlock_irq(&pool->lock); | |
91 | ||
92 | /* per-pool info, no real statistics yet */ | |
93 | temp = scnprintf(next, size, "%-16s %4u %4zu %4zu %2u\n", | |
94 | pool->name, blocks, | |
95 | pages * (pool->allocation / pool->size), | |
96 | pool->size, pages); | |
97 | size -= temp; | |
98 | next += temp; | |
99 | } | |
100 | mutex_unlock(&pools_lock); | |
101 | ||
102 | return PAGE_SIZE - size; | |
103 | } | |
104 | ||
105 | static DEVICE_ATTR(pools, 0444, show_pools, NULL); | |
106 | ||
107 | /** | |
108 | * dma_pool_create - Creates a pool of consistent memory blocks, for dma. | |
109 | * @name: name of pool, for diagnostics | |
110 | * @dev: device that will be doing the DMA | |
111 | * @size: size of the blocks in this pool. | |
112 | * @align: alignment requirement for blocks; must be a power of two | |
113 | * @boundary: returned blocks won't cross this power of two boundary | |
114 | * Context: not in_interrupt() | |
115 | * | |
116 | * Given one of these pools, dma_pool_alloc() | |
117 | * may be used to allocate memory. Such memory will all have "consistent" | |
118 | * DMA mappings, accessible by the device and its driver without using | |
119 | * cache flushing primitives. The actual size of blocks allocated may be | |
120 | * larger than requested because of alignment. | |
121 | * | |
122 | * If @boundary is nonzero, objects returned from dma_pool_alloc() won't | |
123 | * cross that size boundary. This is useful for devices which have | |
124 | * addressing restrictions on individual DMA transfers, such as not crossing | |
125 | * boundaries of 4KBytes. | |
126 | * | |
127 | * Return: a dma allocation pool with the requested characteristics, or | |
128 | * %NULL if one can't be created. | |
129 | */ | |
130 | struct dma_pool *dma_pool_create(const char *name, struct device *dev, | |
131 | size_t size, size_t align, size_t boundary) | |
132 | { | |
133 | struct dma_pool *retval; | |
134 | size_t allocation; | |
135 | bool empty = false; | |
136 | ||
137 | if (align == 0) | |
138 | align = 1; | |
139 | else if (align & (align - 1)) | |
140 | return NULL; | |
141 | ||
142 | if (size == 0) | |
143 | return NULL; | |
144 | else if (size < 4) | |
145 | size = 4; | |
146 | ||
147 | if ((size % align) != 0) | |
148 | size = ALIGN(size, align); | |
149 | ||
150 | allocation = max_t(size_t, size, PAGE_SIZE); | |
151 | ||
152 | if (!boundary) | |
153 | boundary = allocation; | |
154 | else if ((boundary < size) || (boundary & (boundary - 1))) | |
155 | return NULL; | |
156 | ||
157 | retval = kmalloc_node(sizeof(*retval), GFP_KERNEL, dev_to_node(dev)); | |
158 | if (!retval) | |
159 | return retval; | |
160 | ||
161 | strlcpy(retval->name, name, sizeof(retval->name)); | |
162 | ||
163 | retval->dev = dev; | |
164 | ||
165 | INIT_LIST_HEAD(&retval->page_list); | |
166 | spin_lock_init(&retval->lock); | |
167 | retval->size = size; | |
168 | retval->boundary = boundary; | |
169 | retval->allocation = allocation; | |
170 | ||
171 | INIT_LIST_HEAD(&retval->pools); | |
172 | ||
173 | /* | |
174 | * pools_lock ensures that the ->dma_pools list does not get corrupted. | |
175 | * pools_reg_lock ensures that there is not a race between | |
176 | * dma_pool_create() and dma_pool_destroy() or within dma_pool_create() | |
177 | * when the first invocation of dma_pool_create() failed on | |
178 | * device_create_file() and the second assumes that it has been done (I | |
179 | * know it is a short window). | |
180 | */ | |
181 | mutex_lock(&pools_reg_lock); | |
182 | mutex_lock(&pools_lock); | |
183 | if (list_empty(&dev->dma_pools)) | |
184 | empty = true; | |
185 | list_add(&retval->pools, &dev->dma_pools); | |
186 | mutex_unlock(&pools_lock); | |
187 | if (empty) { | |
188 | int err; | |
189 | ||
190 | err = device_create_file(dev, &dev_attr_pools); | |
191 | if (err) { | |
192 | mutex_lock(&pools_lock); | |
193 | list_del(&retval->pools); | |
194 | mutex_unlock(&pools_lock); | |
195 | mutex_unlock(&pools_reg_lock); | |
196 | kfree(retval); | |
197 | return NULL; | |
198 | } | |
199 | } | |
200 | mutex_unlock(&pools_reg_lock); | |
201 | return retval; | |
202 | } | |
203 | EXPORT_SYMBOL(dma_pool_create); | |
204 | ||
205 | static void pool_initialise_page(struct dma_pool *pool, struct dma_page *page) | |
206 | { | |
207 | unsigned int offset = 0; | |
208 | unsigned int next_boundary = pool->boundary; | |
209 | ||
210 | do { | |
211 | unsigned int next = offset + pool->size; | |
212 | if (unlikely((next + pool->size) >= next_boundary)) { | |
213 | next = next_boundary; | |
214 | next_boundary += pool->boundary; | |
215 | } | |
216 | *(int *)(page->vaddr + offset) = next; | |
217 | offset = next; | |
218 | } while (offset < pool->allocation); | |
219 | } | |
220 | ||
221 | static struct dma_page *pool_alloc_page(struct dma_pool *pool, gfp_t mem_flags) | |
222 | { | |
223 | struct dma_page *page; | |
224 | ||
225 | page = kmalloc(sizeof(*page), mem_flags); | |
226 | if (!page) | |
227 | return NULL; | |
228 | page->vaddr = dma_alloc_coherent(pool->dev, pool->allocation, | |
229 | &page->dma, mem_flags); | |
230 | if (page->vaddr) { | |
231 | #ifdef DMAPOOL_DEBUG | |
232 | memset(page->vaddr, POOL_POISON_FREED, pool->allocation); | |
233 | #endif | |
234 | pool_initialise_page(pool, page); | |
235 | page->in_use = 0; | |
236 | page->offset = 0; | |
237 | } else { | |
238 | kfree(page); | |
239 | page = NULL; | |
240 | } | |
241 | return page; | |
242 | } | |
243 | ||
244 | static inline bool is_page_busy(struct dma_page *page) | |
245 | { | |
246 | return page->in_use != 0; | |
247 | } | |
248 | ||
249 | static void pool_free_page(struct dma_pool *pool, struct dma_page *page) | |
250 | { | |
251 | dma_addr_t dma = page->dma; | |
252 | ||
253 | #ifdef DMAPOOL_DEBUG | |
254 | memset(page->vaddr, POOL_POISON_FREED, pool->allocation); | |
255 | #endif | |
256 | dma_free_coherent(pool->dev, pool->allocation, page->vaddr, dma); | |
257 | list_del(&page->page_list); | |
258 | kfree(page); | |
259 | } | |
260 | ||
261 | /** | |
262 | * dma_pool_destroy - destroys a pool of dma memory blocks. | |
263 | * @pool: dma pool that will be destroyed | |
264 | * Context: !in_interrupt() | |
265 | * | |
266 | * Caller guarantees that no more memory from the pool is in use, | |
267 | * and that nothing will try to use the pool after this call. | |
268 | */ | |
269 | void dma_pool_destroy(struct dma_pool *pool) | |
270 | { | |
271 | bool empty = false; | |
272 | ||
273 | if (unlikely(!pool)) | |
274 | return; | |
275 | ||
276 | mutex_lock(&pools_reg_lock); | |
277 | mutex_lock(&pools_lock); | |
278 | list_del(&pool->pools); | |
279 | if (pool->dev && list_empty(&pool->dev->dma_pools)) | |
280 | empty = true; | |
281 | mutex_unlock(&pools_lock); | |
282 | if (empty) | |
283 | device_remove_file(pool->dev, &dev_attr_pools); | |
284 | mutex_unlock(&pools_reg_lock); | |
285 | ||
286 | while (!list_empty(&pool->page_list)) { | |
287 | struct dma_page *page; | |
288 | page = list_entry(pool->page_list.next, | |
289 | struct dma_page, page_list); | |
290 | if (is_page_busy(page)) { | |
291 | if (pool->dev) | |
292 | dev_err(pool->dev, | |
293 | "dma_pool_destroy %s, %p busy\n", | |
294 | pool->name, page->vaddr); | |
295 | else | |
296 | pr_err("dma_pool_destroy %s, %p busy\n", | |
297 | pool->name, page->vaddr); | |
298 | /* leak the still-in-use consistent memory */ | |
299 | list_del(&page->page_list); | |
300 | kfree(page); | |
301 | } else | |
302 | pool_free_page(pool, page); | |
303 | } | |
304 | ||
305 | kfree(pool); | |
306 | } | |
307 | EXPORT_SYMBOL(dma_pool_destroy); | |
308 | ||
309 | /** | |
310 | * dma_pool_alloc - get a block of consistent memory | |
311 | * @pool: dma pool that will produce the block | |
312 | * @mem_flags: GFP_* bitmask | |
313 | * @handle: pointer to dma address of block | |
314 | * | |
315 | * Return: the kernel virtual address of a currently unused block, | |
316 | * and reports its dma address through the handle. | |
317 | * If such a memory block can't be allocated, %NULL is returned. | |
318 | */ | |
319 | void *dma_pool_alloc(struct dma_pool *pool, gfp_t mem_flags, | |
320 | dma_addr_t *handle) | |
321 | { | |
322 | unsigned long flags; | |
323 | struct dma_page *page; | |
324 | size_t offset; | |
325 | void *retval; | |
326 | ||
327 | might_sleep_if(gfpflags_allow_blocking(mem_flags)); | |
328 | ||
329 | spin_lock_irqsave(&pool->lock, flags); | |
330 | list_for_each_entry(page, &pool->page_list, page_list) { | |
331 | if (page->offset < pool->allocation) | |
332 | goto ready; | |
333 | } | |
334 | ||
335 | /* pool_alloc_page() might sleep, so temporarily drop &pool->lock */ | |
336 | spin_unlock_irqrestore(&pool->lock, flags); | |
337 | ||
338 | page = pool_alloc_page(pool, mem_flags & (~__GFP_ZERO)); | |
339 | if (!page) | |
340 | return NULL; | |
341 | ||
342 | spin_lock_irqsave(&pool->lock, flags); | |
343 | ||
344 | list_add(&page->page_list, &pool->page_list); | |
345 | ready: | |
346 | page->in_use++; | |
347 | offset = page->offset; | |
348 | page->offset = *(int *)(page->vaddr + offset); | |
349 | retval = offset + page->vaddr; | |
350 | *handle = offset + page->dma; | |
351 | #ifdef DMAPOOL_DEBUG | |
352 | { | |
353 | int i; | |
354 | u8 *data = retval; | |
355 | /* page->offset is stored in first 4 bytes */ | |
356 | for (i = sizeof(page->offset); i < pool->size; i++) { | |
357 | if (data[i] == POOL_POISON_FREED) | |
358 | continue; | |
359 | if (pool->dev) | |
360 | dev_err(pool->dev, | |
361 | "dma_pool_alloc %s, %p (corrupted)\n", | |
362 | pool->name, retval); | |
363 | else | |
364 | pr_err("dma_pool_alloc %s, %p (corrupted)\n", | |
365 | pool->name, retval); | |
366 | ||
367 | /* | |
368 | * Dump the first 4 bytes even if they are not | |
369 | * POOL_POISON_FREED | |
370 | */ | |
371 | print_hex_dump(KERN_ERR, "", DUMP_PREFIX_OFFSET, 16, 1, | |
372 | data, pool->size, 1); | |
373 | break; | |
374 | } | |
375 | } | |
376 | if (!(mem_flags & __GFP_ZERO)) | |
377 | memset(retval, POOL_POISON_ALLOCATED, pool->size); | |
378 | #endif | |
379 | spin_unlock_irqrestore(&pool->lock, flags); | |
380 | ||
381 | if (want_init_on_alloc(mem_flags)) | |
382 | memset(retval, 0, pool->size); | |
383 | ||
384 | return retval; | |
385 | } | |
386 | EXPORT_SYMBOL(dma_pool_alloc); | |
387 | ||
388 | static struct dma_page *pool_find_page(struct dma_pool *pool, dma_addr_t dma) | |
389 | { | |
390 | struct dma_page *page; | |
391 | ||
392 | list_for_each_entry(page, &pool->page_list, page_list) { | |
393 | if (dma < page->dma) | |
394 | continue; | |
395 | if ((dma - page->dma) < pool->allocation) | |
396 | return page; | |
397 | } | |
398 | return NULL; | |
399 | } | |
400 | ||
401 | /** | |
402 | * dma_pool_free - put block back into dma pool | |
403 | * @pool: the dma pool holding the block | |
404 | * @vaddr: virtual address of block | |
405 | * @dma: dma address of block | |
406 | * | |
407 | * Caller promises neither device nor driver will again touch this block | |
408 | * unless it is first re-allocated. | |
409 | */ | |
410 | void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma) | |
411 | { | |
412 | struct dma_page *page; | |
413 | unsigned long flags; | |
414 | unsigned int offset; | |
415 | ||
416 | spin_lock_irqsave(&pool->lock, flags); | |
417 | page = pool_find_page(pool, dma); | |
418 | if (!page) { | |
419 | spin_unlock_irqrestore(&pool->lock, flags); | |
420 | if (pool->dev) | |
421 | dev_err(pool->dev, | |
422 | "dma_pool_free %s, %p/%lx (bad dma)\n", | |
423 | pool->name, vaddr, (unsigned long)dma); | |
424 | else | |
425 | pr_err("dma_pool_free %s, %p/%lx (bad dma)\n", | |
426 | pool->name, vaddr, (unsigned long)dma); | |
427 | return; | |
428 | } | |
429 | ||
430 | offset = vaddr - page->vaddr; | |
431 | if (want_init_on_free()) | |
432 | memset(vaddr, 0, pool->size); | |
433 | #ifdef DMAPOOL_DEBUG | |
434 | if ((dma - page->dma) != offset) { | |
435 | spin_unlock_irqrestore(&pool->lock, flags); | |
436 | if (pool->dev) | |
437 | dev_err(pool->dev, | |
438 | "dma_pool_free %s, %p (bad vaddr)/%pad\n", | |
439 | pool->name, vaddr, &dma); | |
440 | else | |
441 | pr_err("dma_pool_free %s, %p (bad vaddr)/%pad\n", | |
442 | pool->name, vaddr, &dma); | |
443 | return; | |
444 | } | |
445 | { | |
446 | unsigned int chain = page->offset; | |
447 | while (chain < pool->allocation) { | |
448 | if (chain != offset) { | |
449 | chain = *(int *)(page->vaddr + chain); | |
450 | continue; | |
451 | } | |
452 | spin_unlock_irqrestore(&pool->lock, flags); | |
453 | if (pool->dev) | |
454 | dev_err(pool->dev, "dma_pool_free %s, dma %pad already free\n", | |
455 | pool->name, &dma); | |
456 | else | |
457 | pr_err("dma_pool_free %s, dma %pad already free\n", | |
458 | pool->name, &dma); | |
459 | return; | |
460 | } | |
461 | } | |
462 | memset(vaddr, POOL_POISON_FREED, pool->size); | |
463 | #endif | |
464 | ||
465 | page->in_use--; | |
466 | *(int *)vaddr = page->offset; | |
467 | page->offset = offset; | |
468 | /* | |
469 | * Resist a temptation to do | |
470 | * if (!is_page_busy(page)) pool_free_page(pool, page); | |
471 | * Better have a few empty pages hang around. | |
472 | */ | |
473 | spin_unlock_irqrestore(&pool->lock, flags); | |
474 | } | |
475 | EXPORT_SYMBOL(dma_pool_free); | |
476 | ||
477 | /* | |
478 | * Managed DMA pool | |
479 | */ | |
480 | static void dmam_pool_release(struct device *dev, void *res) | |
481 | { | |
482 | struct dma_pool *pool = *(struct dma_pool **)res; | |
483 | ||
484 | dma_pool_destroy(pool); | |
485 | } | |
486 | ||
487 | static int dmam_pool_match(struct device *dev, void *res, void *match_data) | |
488 | { | |
489 | return *(struct dma_pool **)res == match_data; | |
490 | } | |
491 | ||
492 | /** | |
493 | * dmam_pool_create - Managed dma_pool_create() | |
494 | * @name: name of pool, for diagnostics | |
495 | * @dev: device that will be doing the DMA | |
496 | * @size: size of the blocks in this pool. | |
497 | * @align: alignment requirement for blocks; must be a power of two | |
498 | * @allocation: returned blocks won't cross this boundary (or zero) | |
499 | * | |
500 | * Managed dma_pool_create(). DMA pool created with this function is | |
501 | * automatically destroyed on driver detach. | |
502 | * | |
503 | * Return: a managed dma allocation pool with the requested | |
504 | * characteristics, or %NULL if one can't be created. | |
505 | */ | |
506 | struct dma_pool *dmam_pool_create(const char *name, struct device *dev, | |
507 | size_t size, size_t align, size_t allocation) | |
508 | { | |
509 | struct dma_pool **ptr, *pool; | |
510 | ||
511 | ptr = devres_alloc(dmam_pool_release, sizeof(*ptr), GFP_KERNEL); | |
512 | if (!ptr) | |
513 | return NULL; | |
514 | ||
515 | pool = *ptr = dma_pool_create(name, dev, size, align, allocation); | |
516 | if (pool) | |
517 | devres_add(dev, ptr); | |
518 | else | |
519 | devres_free(ptr); | |
520 | ||
521 | return pool; | |
522 | } | |
523 | EXPORT_SYMBOL(dmam_pool_create); | |
524 | ||
525 | /** | |
526 | * dmam_pool_destroy - Managed dma_pool_destroy() | |
527 | * @pool: dma pool that will be destroyed | |
528 | * | |
529 | * Managed dma_pool_destroy(). | |
530 | */ | |
531 | void dmam_pool_destroy(struct dma_pool *pool) | |
532 | { | |
533 | struct device *dev = pool->dev; | |
534 | ||
535 | WARN_ON(devres_release(dev, dmam_pool_release, dmam_pool_match, pool)); | |
536 | } | |
537 | EXPORT_SYMBOL(dmam_pool_destroy); |