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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 size = ALIGN(size, align);
148 allocation = max_t(size_t, size, PAGE_SIZE);
149
150 if (!boundary)
151 boundary = allocation;
152 else if ((boundary < size) || (boundary & (boundary - 1)))
153 return NULL;
154
155 retval = kmalloc_node(sizeof(*retval), GFP_KERNEL, dev_to_node(dev));
156 if (!retval)
157 return retval;
158
159 strlcpy(retval->name, name, sizeof(retval->name));
160
161 retval->dev = dev;
162
163 INIT_LIST_HEAD(&retval->page_list);
164 spin_lock_init(&retval->lock);
165 retval->size = size;
166 retval->boundary = boundary;
167 retval->allocation = allocation;
168
169 INIT_LIST_HEAD(&retval->pools);
170
171 /*
172 * pools_lock ensures that the ->dma_pools list does not get corrupted.
173 * pools_reg_lock ensures that there is not a race between
174 * dma_pool_create() and dma_pool_destroy() or within dma_pool_create()
175 * when the first invocation of dma_pool_create() failed on
176 * device_create_file() and the second assumes that it has been done (I
177 * know it is a short window).
178 */
179 mutex_lock(&pools_reg_lock);
180 mutex_lock(&pools_lock);
181 if (list_empty(&dev->dma_pools))
182 empty = true;
183 list_add(&retval->pools, &dev->dma_pools);
184 mutex_unlock(&pools_lock);
185 if (empty) {
186 int err;
187
188 err = device_create_file(dev, &dev_attr_pools);
189 if (err) {
190 mutex_lock(&pools_lock);
191 list_del(&retval->pools);
192 mutex_unlock(&pools_lock);
193 mutex_unlock(&pools_reg_lock);
194 kfree(retval);
195 return NULL;
196 }
197 }
198 mutex_unlock(&pools_reg_lock);
199 return retval;
200}
201EXPORT_SYMBOL(dma_pool_create);
202
203static void pool_initialise_page(struct dma_pool *pool, struct dma_page *page)
204{
205 unsigned int offset = 0;
206 unsigned int next_boundary = pool->boundary;
207
208 do {
209 unsigned int next = offset + pool->size;
210 if (unlikely((next + pool->size) >= next_boundary)) {
211 next = next_boundary;
212 next_boundary += pool->boundary;
213 }
214 *(int *)(page->vaddr + offset) = next;
215 offset = next;
216 } while (offset < pool->allocation);
217}
218
219static struct dma_page *pool_alloc_page(struct dma_pool *pool, gfp_t mem_flags)
220{
221 struct dma_page *page;
222
223 page = kmalloc(sizeof(*page), mem_flags);
224 if (!page)
225 return NULL;
226 page->vaddr = dma_alloc_coherent(pool->dev, pool->allocation,
227 &page->dma, mem_flags);
228 if (page->vaddr) {
229#ifdef DMAPOOL_DEBUG
230 memset(page->vaddr, POOL_POISON_FREED, pool->allocation);
231#endif
232 pool_initialise_page(pool, page);
233 page->in_use = 0;
234 page->offset = 0;
235 } else {
236 kfree(page);
237 page = NULL;
238 }
239 return page;
240}
241
242static inline bool is_page_busy(struct dma_page *page)
243{
244 return page->in_use != 0;
245}
246
247static void pool_free_page(struct dma_pool *pool, struct dma_page *page)
248{
249 dma_addr_t dma = page->dma;
250
251#ifdef DMAPOOL_DEBUG
252 memset(page->vaddr, POOL_POISON_FREED, pool->allocation);
253#endif
254 dma_free_coherent(pool->dev, pool->allocation, page->vaddr, dma);
255 list_del(&page->page_list);
256 kfree(page);
257}
258
259/**
260 * dma_pool_destroy - destroys a pool of dma memory blocks.
261 * @pool: dma pool that will be destroyed
262 * Context: !in_interrupt()
263 *
264 * Caller guarantees that no more memory from the pool is in use,
265 * and that nothing will try to use the pool after this call.
266 */
267void dma_pool_destroy(struct dma_pool *pool)
268{
269 bool empty = false;
270
271 if (unlikely(!pool))
272 return;
273
274 mutex_lock(&pools_reg_lock);
275 mutex_lock(&pools_lock);
276 list_del(&pool->pools);
277 if (pool->dev && list_empty(&pool->dev->dma_pools))
278 empty = true;
279 mutex_unlock(&pools_lock);
280 if (empty)
281 device_remove_file(pool->dev, &dev_attr_pools);
282 mutex_unlock(&pools_reg_lock);
283
284 while (!list_empty(&pool->page_list)) {
285 struct dma_page *page;
286 page = list_entry(pool->page_list.next,
287 struct dma_page, page_list);
288 if (is_page_busy(page)) {
289 if (pool->dev)
290 dev_err(pool->dev,
291 "dma_pool_destroy %s, %p busy\n",
292 pool->name, page->vaddr);
293 else
294 pr_err("dma_pool_destroy %s, %p busy\n",
295 pool->name, page->vaddr);
296 /* leak the still-in-use consistent memory */
297 list_del(&page->page_list);
298 kfree(page);
299 } else
300 pool_free_page(pool, page);
301 }
302
303 kfree(pool);
304}
305EXPORT_SYMBOL(dma_pool_destroy);
306
307/**
308 * dma_pool_alloc - get a block of consistent memory
309 * @pool: dma pool that will produce the block
310 * @mem_flags: GFP_* bitmask
311 * @handle: pointer to dma address of block
312 *
313 * Return: the kernel virtual address of a currently unused block,
314 * and reports its dma address through the handle.
315 * If such a memory block can't be allocated, %NULL is returned.
316 */
317void *dma_pool_alloc(struct dma_pool *pool, gfp_t mem_flags,
318 dma_addr_t *handle)
319{
320 unsigned long flags;
321 struct dma_page *page;
322 size_t offset;
323 void *retval;
324
325 might_sleep_if(gfpflags_allow_blocking(mem_flags));
326
327 spin_lock_irqsave(&pool->lock, flags);
328 list_for_each_entry(page, &pool->page_list, page_list) {
329 if (page->offset < pool->allocation)
330 goto ready;
331 }
332
333 /* pool_alloc_page() might sleep, so temporarily drop &pool->lock */
334 spin_unlock_irqrestore(&pool->lock, flags);
335
336 page = pool_alloc_page(pool, mem_flags & (~__GFP_ZERO));
337 if (!page)
338 return NULL;
339
340 spin_lock_irqsave(&pool->lock, flags);
341
342 list_add(&page->page_list, &pool->page_list);
343 ready:
344 page->in_use++;
345 offset = page->offset;
346 page->offset = *(int *)(page->vaddr + offset);
347 retval = offset + page->vaddr;
348 *handle = offset + page->dma;
349#ifdef DMAPOOL_DEBUG
350 {
351 int i;
352 u8 *data = retval;
353 /* page->offset is stored in first 4 bytes */
354 for (i = sizeof(page->offset); i < pool->size; i++) {
355 if (data[i] == POOL_POISON_FREED)
356 continue;
357 if (pool->dev)
358 dev_err(pool->dev,
359 "dma_pool_alloc %s, %p (corrupted)\n",
360 pool->name, retval);
361 else
362 pr_err("dma_pool_alloc %s, %p (corrupted)\n",
363 pool->name, retval);
364
365 /*
366 * Dump the first 4 bytes even if they are not
367 * POOL_POISON_FREED
368 */
369 print_hex_dump(KERN_ERR, "", DUMP_PREFIX_OFFSET, 16, 1,
370 data, pool->size, 1);
371 break;
372 }
373 }
374 if (!(mem_flags & __GFP_ZERO))
375 memset(retval, POOL_POISON_ALLOCATED, pool->size);
376#endif
377 spin_unlock_irqrestore(&pool->lock, flags);
378
379 if (want_init_on_alloc(mem_flags))
380 memset(retval, 0, pool->size);
381
382 return retval;
383}
384EXPORT_SYMBOL(dma_pool_alloc);
385
386static struct dma_page *pool_find_page(struct dma_pool *pool, dma_addr_t dma)
387{
388 struct dma_page *page;
389
390 list_for_each_entry(page, &pool->page_list, page_list) {
391 if (dma < page->dma)
392 continue;
393 if ((dma - page->dma) < pool->allocation)
394 return page;
395 }
396 return NULL;
397}
398
399/**
400 * dma_pool_free - put block back into dma pool
401 * @pool: the dma pool holding the block
402 * @vaddr: virtual address of block
403 * @dma: dma address of block
404 *
405 * Caller promises neither device nor driver will again touch this block
406 * unless it is first re-allocated.
407 */
408void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma)
409{
410 struct dma_page *page;
411 unsigned long flags;
412 unsigned int offset;
413
414 spin_lock_irqsave(&pool->lock, flags);
415 page = pool_find_page(pool, dma);
416 if (!page) {
417 spin_unlock_irqrestore(&pool->lock, flags);
418 if (pool->dev)
419 dev_err(pool->dev,
420 "dma_pool_free %s, %p/%lx (bad dma)\n",
421 pool->name, vaddr, (unsigned long)dma);
422 else
423 pr_err("dma_pool_free %s, %p/%lx (bad dma)\n",
424 pool->name, vaddr, (unsigned long)dma);
425 return;
426 }
427
428 offset = vaddr - page->vaddr;
429 if (want_init_on_free())
430 memset(vaddr, 0, pool->size);
431#ifdef DMAPOOL_DEBUG
432 if ((dma - page->dma) != offset) {
433 spin_unlock_irqrestore(&pool->lock, flags);
434 if (pool->dev)
435 dev_err(pool->dev,
436 "dma_pool_free %s, %p (bad vaddr)/%pad\n",
437 pool->name, vaddr, &dma);
438 else
439 pr_err("dma_pool_free %s, %p (bad vaddr)/%pad\n",
440 pool->name, vaddr, &dma);
441 return;
442 }
443 {
444 unsigned int chain = page->offset;
445 while (chain < pool->allocation) {
446 if (chain != offset) {
447 chain = *(int *)(page->vaddr + chain);
448 continue;
449 }
450 spin_unlock_irqrestore(&pool->lock, flags);
451 if (pool->dev)
452 dev_err(pool->dev, "dma_pool_free %s, dma %pad already free\n",
453 pool->name, &dma);
454 else
455 pr_err("dma_pool_free %s, dma %pad already free\n",
456 pool->name, &dma);
457 return;
458 }
459 }
460 memset(vaddr, POOL_POISON_FREED, pool->size);
461#endif
462
463 page->in_use--;
464 *(int *)vaddr = page->offset;
465 page->offset = offset;
466 /*
467 * Resist a temptation to do
468 * if (!is_page_busy(page)) pool_free_page(pool, page);
469 * Better have a few empty pages hang around.
470 */
471 spin_unlock_irqrestore(&pool->lock, flags);
472}
473EXPORT_SYMBOL(dma_pool_free);
474
475/*
476 * Managed DMA pool
477 */
478static void dmam_pool_release(struct device *dev, void *res)
479{
480 struct dma_pool *pool = *(struct dma_pool **)res;
481
482 dma_pool_destroy(pool);
483}
484
485static int dmam_pool_match(struct device *dev, void *res, void *match_data)
486{
487 return *(struct dma_pool **)res == match_data;
488}
489
490/**
491 * dmam_pool_create - Managed dma_pool_create()
492 * @name: name of pool, for diagnostics
493 * @dev: device that will be doing the DMA
494 * @size: size of the blocks in this pool.
495 * @align: alignment requirement for blocks; must be a power of two
496 * @allocation: returned blocks won't cross this boundary (or zero)
497 *
498 * Managed dma_pool_create(). DMA pool created with this function is
499 * automatically destroyed on driver detach.
500 *
501 * Return: a managed dma allocation pool with the requested
502 * characteristics, or %NULL if one can't be created.
503 */
504struct dma_pool *dmam_pool_create(const char *name, struct device *dev,
505 size_t size, size_t align, size_t allocation)
506{
507 struct dma_pool **ptr, *pool;
508
509 ptr = devres_alloc(dmam_pool_release, sizeof(*ptr), GFP_KERNEL);
510 if (!ptr)
511 return NULL;
512
513 pool = *ptr = dma_pool_create(name, dev, size, align, allocation);
514 if (pool)
515 devres_add(dev, ptr);
516 else
517 devres_free(ptr);
518
519 return pool;
520}
521EXPORT_SYMBOL(dmam_pool_create);
522
523/**
524 * dmam_pool_destroy - Managed dma_pool_destroy()
525 * @pool: dma pool that will be destroyed
526 *
527 * Managed dma_pool_destroy().
528 */
529void dmam_pool_destroy(struct dma_pool *pool)
530{
531 struct device *dev = pool->dev;
532
533 WARN_ON(devres_release(dev, dmam_pool_release, dmam_pool_match, pool));
534}
535EXPORT_SYMBOL(dmam_pool_destroy);
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
45struct 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 wait_queue_head_t waitq;
54 struct list_head pools;
55};
56
57struct dma_page { /* cacheable header for 'allocation' bytes */
58 struct list_head page_list;
59 void *vaddr;
60 dma_addr_t dma;
61 unsigned int in_use;
62 unsigned int offset;
63};
64
65#define POOL_TIMEOUT_JIFFIES ((100 /* msec */ * HZ) / 1000)
66
67static DEFINE_MUTEX(pools_lock);
68
69static ssize_t
70show_pools(struct device *dev, struct device_attribute *attr, char *buf)
71{
72 unsigned temp;
73 unsigned size;
74 char *next;
75 struct dma_page *page;
76 struct dma_pool *pool;
77
78 next = buf;
79 size = PAGE_SIZE;
80
81 temp = scnprintf(next, size, "poolinfo - 0.1\n");
82 size -= temp;
83 next += temp;
84
85 mutex_lock(&pools_lock);
86 list_for_each_entry(pool, &dev->dma_pools, pools) {
87 unsigned pages = 0;
88 unsigned blocks = 0;
89
90 spin_lock_irq(&pool->lock);
91 list_for_each_entry(page, &pool->page_list, page_list) {
92 pages++;
93 blocks += page->in_use;
94 }
95 spin_unlock_irq(&pool->lock);
96
97 /* per-pool info, no real statistics yet */
98 temp = scnprintf(next, size, "%-16s %4u %4Zu %4Zu %2u\n",
99 pool->name, blocks,
100 pages * (pool->allocation / pool->size),
101 pool->size, pages);
102 size -= temp;
103 next += temp;
104 }
105 mutex_unlock(&pools_lock);
106
107 return PAGE_SIZE - size;
108}
109
110static DEVICE_ATTR(pools, S_IRUGO, show_pools, NULL);
111
112/**
113 * dma_pool_create - Creates a pool of consistent memory blocks, for dma.
114 * @name: name of pool, for diagnostics
115 * @dev: device that will be doing the DMA
116 * @size: size of the blocks in this pool.
117 * @align: alignment requirement for blocks; must be a power of two
118 * @boundary: returned blocks won't cross this power of two boundary
119 * Context: !in_interrupt()
120 *
121 * Returns a dma allocation pool with the requested characteristics, or
122 * null if one can't be created. Given one of these pools, dma_pool_alloc()
123 * may be used to allocate memory. Such memory will all have "consistent"
124 * DMA mappings, accessible by the device and its driver without using
125 * cache flushing primitives. The actual size of blocks allocated may be
126 * larger than requested because of alignment.
127 *
128 * If @boundary is nonzero, objects returned from dma_pool_alloc() won't
129 * cross that size boundary. This is useful for devices which have
130 * addressing restrictions on individual DMA transfers, such as not crossing
131 * boundaries of 4KBytes.
132 */
133struct dma_pool *dma_pool_create(const char *name, struct device *dev,
134 size_t size, size_t align, size_t boundary)
135{
136 struct dma_pool *retval;
137 size_t allocation;
138
139 if (align == 0) {
140 align = 1;
141 } else if (align & (align - 1)) {
142 return NULL;
143 }
144
145 if (size == 0) {
146 return NULL;
147 } else if (size < 4) {
148 size = 4;
149 }
150
151 if ((size % align) != 0)
152 size = ALIGN(size, align);
153
154 allocation = max_t(size_t, size, PAGE_SIZE);
155
156 if (!boundary) {
157 boundary = allocation;
158 } else if ((boundary < size) || (boundary & (boundary - 1))) {
159 return NULL;
160 }
161
162 retval = kmalloc_node(sizeof(*retval), GFP_KERNEL, dev_to_node(dev));
163 if (!retval)
164 return retval;
165
166 strlcpy(retval->name, name, sizeof(retval->name));
167
168 retval->dev = dev;
169
170 INIT_LIST_HEAD(&retval->page_list);
171 spin_lock_init(&retval->lock);
172 retval->size = size;
173 retval->boundary = boundary;
174 retval->allocation = allocation;
175 init_waitqueue_head(&retval->waitq);
176
177 if (dev) {
178 int ret;
179
180 mutex_lock(&pools_lock);
181 if (list_empty(&dev->dma_pools))
182 ret = device_create_file(dev, &dev_attr_pools);
183 else
184 ret = 0;
185 /* note: not currently insisting "name" be unique */
186 if (!ret)
187 list_add(&retval->pools, &dev->dma_pools);
188 else {
189 kfree(retval);
190 retval = NULL;
191 }
192 mutex_unlock(&pools_lock);
193 } else
194 INIT_LIST_HEAD(&retval->pools);
195
196 return retval;
197}
198EXPORT_SYMBOL(dma_pool_create);
199
200static void pool_initialise_page(struct dma_pool *pool, struct dma_page *page)
201{
202 unsigned int offset = 0;
203 unsigned int next_boundary = pool->boundary;
204
205 do {
206 unsigned int next = offset + pool->size;
207 if (unlikely((next + pool->size) >= next_boundary)) {
208 next = next_boundary;
209 next_boundary += pool->boundary;
210 }
211 *(int *)(page->vaddr + offset) = next;
212 offset = next;
213 } while (offset < pool->allocation);
214}
215
216static struct dma_page *pool_alloc_page(struct dma_pool *pool, gfp_t mem_flags)
217{
218 struct dma_page *page;
219
220 page = kmalloc(sizeof(*page), mem_flags);
221 if (!page)
222 return NULL;
223 page->vaddr = dma_alloc_coherent(pool->dev, pool->allocation,
224 &page->dma, mem_flags);
225 if (page->vaddr) {
226#ifdef DMAPOOL_DEBUG
227 memset(page->vaddr, POOL_POISON_FREED, pool->allocation);
228#endif
229 pool_initialise_page(pool, page);
230 list_add(&page->page_list, &pool->page_list);
231 page->in_use = 0;
232 page->offset = 0;
233 } else {
234 kfree(page);
235 page = NULL;
236 }
237 return page;
238}
239
240static inline int is_page_busy(struct dma_page *page)
241{
242 return page->in_use != 0;
243}
244
245static void pool_free_page(struct dma_pool *pool, struct dma_page *page)
246{
247 dma_addr_t dma = page->dma;
248
249#ifdef DMAPOOL_DEBUG
250 memset(page->vaddr, POOL_POISON_FREED, pool->allocation);
251#endif
252 dma_free_coherent(pool->dev, pool->allocation, page->vaddr, dma);
253 list_del(&page->page_list);
254 kfree(page);
255}
256
257/**
258 * dma_pool_destroy - destroys a pool of dma memory blocks.
259 * @pool: dma pool that will be destroyed
260 * Context: !in_interrupt()
261 *
262 * Caller guarantees that no more memory from the pool is in use,
263 * and that nothing will try to use the pool after this call.
264 */
265void dma_pool_destroy(struct dma_pool *pool)
266{
267 mutex_lock(&pools_lock);
268 list_del(&pool->pools);
269 if (pool->dev && list_empty(&pool->dev->dma_pools))
270 device_remove_file(pool->dev, &dev_attr_pools);
271 mutex_unlock(&pools_lock);
272
273 while (!list_empty(&pool->page_list)) {
274 struct dma_page *page;
275 page = list_entry(pool->page_list.next,
276 struct dma_page, page_list);
277 if (is_page_busy(page)) {
278 if (pool->dev)
279 dev_err(pool->dev,
280 "dma_pool_destroy %s, %p busy\n",
281 pool->name, page->vaddr);
282 else
283 printk(KERN_ERR
284 "dma_pool_destroy %s, %p busy\n",
285 pool->name, page->vaddr);
286 /* leak the still-in-use consistent memory */
287 list_del(&page->page_list);
288 kfree(page);
289 } else
290 pool_free_page(pool, page);
291 }
292
293 kfree(pool);
294}
295EXPORT_SYMBOL(dma_pool_destroy);
296
297/**
298 * dma_pool_alloc - get a block of consistent memory
299 * @pool: dma pool that will produce the block
300 * @mem_flags: GFP_* bitmask
301 * @handle: pointer to dma address of block
302 *
303 * This returns the kernel virtual address of a currently unused block,
304 * and reports its dma address through the handle.
305 * If such a memory block can't be allocated, %NULL is returned.
306 */
307void *dma_pool_alloc(struct dma_pool *pool, gfp_t mem_flags,
308 dma_addr_t *handle)
309{
310 unsigned long flags;
311 struct dma_page *page;
312 size_t offset;
313 void *retval;
314
315 might_sleep_if(mem_flags & __GFP_WAIT);
316
317 spin_lock_irqsave(&pool->lock, flags);
318 restart:
319 list_for_each_entry(page, &pool->page_list, page_list) {
320 if (page->offset < pool->allocation)
321 goto ready;
322 }
323 page = pool_alloc_page(pool, GFP_ATOMIC);
324 if (!page) {
325 if (mem_flags & __GFP_WAIT) {
326 DECLARE_WAITQUEUE(wait, current);
327
328 __set_current_state(TASK_UNINTERRUPTIBLE);
329 __add_wait_queue(&pool->waitq, &wait);
330 spin_unlock_irqrestore(&pool->lock, flags);
331
332 schedule_timeout(POOL_TIMEOUT_JIFFIES);
333
334 spin_lock_irqsave(&pool->lock, flags);
335 __remove_wait_queue(&pool->waitq, &wait);
336 goto restart;
337 }
338 retval = NULL;
339 goto done;
340 }
341
342 ready:
343 page->in_use++;
344 offset = page->offset;
345 page->offset = *(int *)(page->vaddr + offset);
346 retval = offset + page->vaddr;
347 *handle = offset + page->dma;
348#ifdef DMAPOOL_DEBUG
349 memset(retval, POOL_POISON_ALLOCATED, pool->size);
350#endif
351 done:
352 spin_unlock_irqrestore(&pool->lock, flags);
353 return retval;
354}
355EXPORT_SYMBOL(dma_pool_alloc);
356
357static struct dma_page *pool_find_page(struct dma_pool *pool, dma_addr_t dma)
358{
359 struct dma_page *page;
360
361 list_for_each_entry(page, &pool->page_list, page_list) {
362 if (dma < page->dma)
363 continue;
364 if (dma < (page->dma + pool->allocation))
365 return page;
366 }
367 return NULL;
368}
369
370/**
371 * dma_pool_free - put block back into dma pool
372 * @pool: the dma pool holding the block
373 * @vaddr: virtual address of block
374 * @dma: dma address of block
375 *
376 * Caller promises neither device nor driver will again touch this block
377 * unless it is first re-allocated.
378 */
379void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma)
380{
381 struct dma_page *page;
382 unsigned long flags;
383 unsigned int offset;
384
385 spin_lock_irqsave(&pool->lock, flags);
386 page = pool_find_page(pool, dma);
387 if (!page) {
388 spin_unlock_irqrestore(&pool->lock, flags);
389 if (pool->dev)
390 dev_err(pool->dev,
391 "dma_pool_free %s, %p/%lx (bad dma)\n",
392 pool->name, vaddr, (unsigned long)dma);
393 else
394 printk(KERN_ERR "dma_pool_free %s, %p/%lx (bad dma)\n",
395 pool->name, vaddr, (unsigned long)dma);
396 return;
397 }
398
399 offset = vaddr - page->vaddr;
400#ifdef DMAPOOL_DEBUG
401 if ((dma - page->dma) != offset) {
402 spin_unlock_irqrestore(&pool->lock, flags);
403 if (pool->dev)
404 dev_err(pool->dev,
405 "dma_pool_free %s, %p (bad vaddr)/%Lx\n",
406 pool->name, vaddr, (unsigned long long)dma);
407 else
408 printk(KERN_ERR
409 "dma_pool_free %s, %p (bad vaddr)/%Lx\n",
410 pool->name, vaddr, (unsigned long long)dma);
411 return;
412 }
413 {
414 unsigned int chain = page->offset;
415 while (chain < pool->allocation) {
416 if (chain != offset) {
417 chain = *(int *)(page->vaddr + chain);
418 continue;
419 }
420 spin_unlock_irqrestore(&pool->lock, flags);
421 if (pool->dev)
422 dev_err(pool->dev, "dma_pool_free %s, dma %Lx "
423 "already free\n", pool->name,
424 (unsigned long long)dma);
425 else
426 printk(KERN_ERR "dma_pool_free %s, dma %Lx "
427 "already free\n", pool->name,
428 (unsigned long long)dma);
429 return;
430 }
431 }
432 memset(vaddr, POOL_POISON_FREED, pool->size);
433#endif
434
435 page->in_use--;
436 *(int *)vaddr = page->offset;
437 page->offset = offset;
438 if (waitqueue_active(&pool->waitq))
439 wake_up_locked(&pool->waitq);
440 /*
441 * Resist a temptation to do
442 * if (!is_page_busy(page)) pool_free_page(pool, page);
443 * Better have a few empty pages hang around.
444 */
445 spin_unlock_irqrestore(&pool->lock, flags);
446}
447EXPORT_SYMBOL(dma_pool_free);
448
449/*
450 * Managed DMA pool
451 */
452static void dmam_pool_release(struct device *dev, void *res)
453{
454 struct dma_pool *pool = *(struct dma_pool **)res;
455
456 dma_pool_destroy(pool);
457}
458
459static int dmam_pool_match(struct device *dev, void *res, void *match_data)
460{
461 return *(struct dma_pool **)res == match_data;
462}
463
464/**
465 * dmam_pool_create - Managed dma_pool_create()
466 * @name: name of pool, for diagnostics
467 * @dev: device that will be doing the DMA
468 * @size: size of the blocks in this pool.
469 * @align: alignment requirement for blocks; must be a power of two
470 * @allocation: returned blocks won't cross this boundary (or zero)
471 *
472 * Managed dma_pool_create(). DMA pool created with this function is
473 * automatically destroyed on driver detach.
474 */
475struct dma_pool *dmam_pool_create(const char *name, struct device *dev,
476 size_t size, size_t align, size_t allocation)
477{
478 struct dma_pool **ptr, *pool;
479
480 ptr = devres_alloc(dmam_pool_release, sizeof(*ptr), GFP_KERNEL);
481 if (!ptr)
482 return NULL;
483
484 pool = *ptr = dma_pool_create(name, dev, size, align, allocation);
485 if (pool)
486 devres_add(dev, ptr);
487 else
488 devres_free(ptr);
489
490 return pool;
491}
492EXPORT_SYMBOL(dmam_pool_create);
493
494/**
495 * dmam_pool_destroy - Managed dma_pool_destroy()
496 * @pool: dma pool that will be destroyed
497 *
498 * Managed dma_pool_destroy().
499 */
500void dmam_pool_destroy(struct dma_pool *pool)
501{
502 struct device *dev = pool->dev;
503
504 WARN_ON(devres_destroy(dev, dmam_pool_release, dmam_pool_match, pool));
505 dma_pool_destroy(pool);
506}
507EXPORT_SYMBOL(dmam_pool_destroy);