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