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b2139ce0 1// SPDX-License-Identifier: GPL-2.0-only
6182a094
MW
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 *
6182a094
MW
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
a35a3455
MW
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.
6182a094 20 */
1da177e4
LT
21
22#include <linux/device.h>
1da177e4
LT
23#include <linux/dma-mapping.h>
24#include <linux/dmapool.h>
6182a094
MW
25#include <linux/kernel.h>
26#include <linux/list.h>
b95f1b31 27#include <linux/export.h>
6182a094 28#include <linux/mutex.h>
c9cf5528 29#include <linux/poison.h>
e8edc6e0 30#include <linux/sched.h>
6182a094 31#include <linux/slab.h>
7c77509c 32#include <linux/stat.h>
6182a094
MW
33#include <linux/spinlock.h>
34#include <linux/string.h>
35#include <linux/types.h>
36#include <linux/wait.h>
1da177e4 37
b5ee5bef
AK
38#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB_DEBUG_ON)
39#define DMAPOOL_DEBUG 1
40#endif
41
e87aa773
MW
42struct dma_pool { /* the pool */
43 struct list_head page_list;
44 spinlock_t lock;
e87aa773
MW
45 size_t size;
46 struct device *dev;
47 size_t allocation;
e34f44b3 48 size_t boundary;
e87aa773 49 char name[32];
e87aa773 50 struct list_head pools;
1da177e4
LT
51};
52
e87aa773
MW
53struct dma_page { /* cacheable header for 'allocation' bytes */
54 struct list_head page_list;
55 void *vaddr;
56 dma_addr_t dma;
a35a3455
MW
57 unsigned int in_use;
58 unsigned int offset;
1da177e4
LT
59};
60
e87aa773 61static DEFINE_MUTEX(pools_lock);
01c2965f 62static DEFINE_MUTEX(pools_reg_lock);
1da177e4
LT
63
64static ssize_t
e87aa773 65show_pools(struct device *dev, struct device_attribute *attr, char *buf)
1da177e4
LT
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
b2366d68 80 mutex_lock(&pools_lock);
1da177e4
LT
81 list_for_each_entry(pool, &dev->dma_pools, pools) {
82 unsigned pages = 0;
83 unsigned blocks = 0;
84
c4956823 85 spin_lock_irq(&pool->lock);
1da177e4
LT
86 list_for_each_entry(page, &pool->page_list, page_list) {
87 pages++;
88 blocks += page->in_use;
89 }
c4956823 90 spin_unlock_irq(&pool->lock);
1da177e4
LT
91
92 /* per-pool info, no real statistics yet */
5b5e0928 93 temp = scnprintf(next, size, "%-16s %4u %4zu %4zu %2u\n",
a35a3455
MW
94 pool->name, blocks,
95 pages * (pool->allocation / pool->size),
e87aa773 96 pool->size, pages);
1da177e4
LT
97 size -= temp;
98 next += temp;
99 }
b2366d68 100 mutex_unlock(&pools_lock);
1da177e4
LT
101
102 return PAGE_SIZE - size;
103}
e87aa773 104
0825a6f9 105static DEVICE_ATTR(pools, 0444, show_pools, NULL);
1da177e4
LT
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
e34f44b3 113 * @boundary: returned blocks won't cross this power of two boundary
a862f68a 114 * Context: not in_interrupt()
1da177e4 115 *
a862f68a 116 * Given one of these pools, dma_pool_alloc()
1da177e4
LT
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 *
e34f44b3 122 * If @boundary is nonzero, objects returned from dma_pool_alloc() won't
1da177e4
LT
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.
a862f68a
MR
126 *
127 * Return: a dma allocation pool with the requested characteristics, or
128 * %NULL if one can't be created.
1da177e4 129 */
e87aa773 130struct dma_pool *dma_pool_create(const char *name, struct device *dev,
e34f44b3 131 size_t size, size_t align, size_t boundary)
1da177e4 132{
e87aa773 133 struct dma_pool *retval;
e34f44b3 134 size_t allocation;
01c2965f 135 bool empty = false;
1da177e4 136
baa2ef83 137 if (align == 0)
1da177e4 138 align = 1;
baa2ef83 139 else if (align & (align - 1))
1da177e4 140 return NULL;
1da177e4 141
baa2ef83 142 if (size == 0)
399154be 143 return NULL;
baa2ef83 144 else if (size < 4)
a35a3455 145 size = 4;
399154be 146
1386f7a3 147 size = ALIGN(size, align);
e34f44b3
MW
148 allocation = max_t(size_t, size, PAGE_SIZE);
149
baa2ef83 150 if (!boundary)
e34f44b3 151 boundary = allocation;
baa2ef83 152 else if ((boundary < size) || (boundary & (boundary - 1)))
1da177e4
LT
153 return NULL;
154
e34f44b3
MW
155 retval = kmalloc_node(sizeof(*retval), GFP_KERNEL, dev_to_node(dev));
156 if (!retval)
1da177e4
LT
157 return retval;
158
e34f44b3 159 strlcpy(retval->name, name, sizeof(retval->name));
1da177e4
LT
160
161 retval->dev = dev;
162
e87aa773
MW
163 INIT_LIST_HEAD(&retval->page_list);
164 spin_lock_init(&retval->lock);
1da177e4 165 retval->size = size;
e34f44b3 166 retval->boundary = boundary;
1da177e4 167 retval->allocation = allocation;
1da177e4 168
cc6b664a
DY
169 INIT_LIST_HEAD(&retval->pools);
170
01c2965f
SAS
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);
cc6b664a 180 mutex_lock(&pools_lock);
01c2965f
SAS
181 if (list_empty(&dev->dma_pools))
182 empty = true;
183 list_add(&retval->pools, &dev->dma_pools);
cc6b664a 184 mutex_unlock(&pools_lock);
01c2965f
SAS
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);
1da177e4
LT
199 return retval;
200}
e87aa773 201EXPORT_SYMBOL(dma_pool_create);
1da177e4 202
a35a3455
MW
203static void pool_initialise_page(struct dma_pool *pool, struct dma_page *page)
204{
205 unsigned int offset = 0;
e34f44b3 206 unsigned int next_boundary = pool->boundary;
a35a3455
MW
207
208 do {
209 unsigned int next = offset + pool->size;
e34f44b3
MW
210 if (unlikely((next + pool->size) >= next_boundary)) {
211 next = next_boundary;
212 next_boundary += pool->boundary;
213 }
a35a3455
MW
214 *(int *)(page->vaddr + offset) = next;
215 offset = next;
216 } while (offset < pool->allocation);
217}
218
e87aa773 219static struct dma_page *pool_alloc_page(struct dma_pool *pool, gfp_t mem_flags)
1da177e4 220{
e87aa773 221 struct dma_page *page;
1da177e4 222
a35a3455 223 page = kmalloc(sizeof(*page), mem_flags);
1da177e4
LT
224 if (!page)
225 return NULL;
a35a3455 226 page->vaddr = dma_alloc_coherent(pool->dev, pool->allocation,
e87aa773 227 &page->dma, mem_flags);
1da177e4 228 if (page->vaddr) {
b5ee5bef 229#ifdef DMAPOOL_DEBUG
e87aa773 230 memset(page->vaddr, POOL_POISON_FREED, pool->allocation);
1da177e4 231#endif
a35a3455 232 pool_initialise_page(pool, page);
1da177e4 233 page->in_use = 0;
a35a3455 234 page->offset = 0;
1da177e4 235 } else {
e87aa773 236 kfree(page);
1da177e4
LT
237 page = NULL;
238 }
239 return page;
240}
241
d9e7e37b 242static inline bool is_page_busy(struct dma_page *page)
1da177e4 243{
a35a3455 244 return page->in_use != 0;
1da177e4
LT
245}
246
e87aa773 247static void pool_free_page(struct dma_pool *pool, struct dma_page *page)
1da177e4 248{
e87aa773 249 dma_addr_t dma = page->dma;
1da177e4 250
b5ee5bef 251#ifdef DMAPOOL_DEBUG
e87aa773 252 memset(page->vaddr, POOL_POISON_FREED, pool->allocation);
1da177e4 253#endif
e87aa773
MW
254 dma_free_coherent(pool->dev, pool->allocation, page->vaddr, dma);
255 list_del(&page->page_list);
256 kfree(page);
1da177e4
LT
257}
258
1da177e4
LT
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 */
e87aa773 267void dma_pool_destroy(struct dma_pool *pool)
1da177e4 268{
42286f83 269 struct dma_page *page, *tmp;
01c2965f
SAS
270 bool empty = false;
271
44d7175d
SS
272 if (unlikely(!pool))
273 return;
274
01c2965f 275 mutex_lock(&pools_reg_lock);
b2366d68 276 mutex_lock(&pools_lock);
e87aa773
MW
277 list_del(&pool->pools);
278 if (pool->dev && list_empty(&pool->dev->dma_pools))
01c2965f 279 empty = true;
b2366d68 280 mutex_unlock(&pools_lock);
01c2965f
SAS
281 if (empty)
282 device_remove_file(pool->dev, &dev_attr_pools);
283 mutex_unlock(&pools_reg_lock);
1da177e4 284
42286f83 285 list_for_each_entry_safe(page, tmp, &pool->page_list, page_list) {
a35a3455 286 if (is_page_busy(page)) {
1da177e4 287 if (pool->dev)
e87aa773
MW
288 dev_err(pool->dev,
289 "dma_pool_destroy %s, %p busy\n",
1da177e4
LT
290 pool->name, page->vaddr);
291 else
1170532b 292 pr_err("dma_pool_destroy %s, %p busy\n",
e87aa773 293 pool->name, page->vaddr);
1da177e4 294 /* leak the still-in-use consistent memory */
e87aa773
MW
295 list_del(&page->page_list);
296 kfree(page);
1da177e4 297 } else
e87aa773 298 pool_free_page(pool, page);
1da177e4
LT
299 }
300
e87aa773 301 kfree(pool);
1da177e4 302}
e87aa773 303EXPORT_SYMBOL(dma_pool_destroy);
1da177e4
LT
304
305/**
306 * dma_pool_alloc - get a block of consistent memory
307 * @pool: dma pool that will produce the block
308 * @mem_flags: GFP_* bitmask
309 * @handle: pointer to dma address of block
310 *
a862f68a 311 * Return: the kernel virtual address of a currently unused block,
1da177e4 312 * and reports its dma address through the handle.
6182a094 313 * If such a memory block can't be allocated, %NULL is returned.
1da177e4 314 */
e87aa773
MW
315void *dma_pool_alloc(struct dma_pool *pool, gfp_t mem_flags,
316 dma_addr_t *handle)
1da177e4 317{
e87aa773
MW
318 unsigned long flags;
319 struct dma_page *page;
e87aa773
MW
320 size_t offset;
321 void *retval;
322
d0164adc 323 might_sleep_if(gfpflags_allow_blocking(mem_flags));
ea05c844 324
e87aa773 325 spin_lock_irqsave(&pool->lock, flags);
1da177e4 326 list_for_each_entry(page, &pool->page_list, page_list) {
a35a3455
MW
327 if (page->offset < pool->allocation)
328 goto ready;
1da177e4 329 }
1da177e4 330
387870f2
MS
331 /* pool_alloc_page() might sleep, so temporarily drop &pool->lock */
332 spin_unlock_irqrestore(&pool->lock, flags);
1da177e4 333
fa23f56d 334 page = pool_alloc_page(pool, mem_flags & (~__GFP_ZERO));
387870f2
MS
335 if (!page)
336 return NULL;
1da177e4 337
387870f2 338 spin_lock_irqsave(&pool->lock, flags);
1da177e4 339
387870f2 340 list_add(&page->page_list, &pool->page_list);
e87aa773 341 ready:
1da177e4 342 page->in_use++;
a35a3455
MW
343 offset = page->offset;
344 page->offset = *(int *)(page->vaddr + offset);
1da177e4
LT
345 retval = offset + page->vaddr;
346 *handle = offset + page->dma;
b5ee5bef 347#ifdef DMAPOOL_DEBUG
5de55b26
MC
348 {
349 int i;
350 u8 *data = retval;
351 /* page->offset is stored in first 4 bytes */
352 for (i = sizeof(page->offset); i < pool->size; i++) {
353 if (data[i] == POOL_POISON_FREED)
354 continue;
355 if (pool->dev)
356 dev_err(pool->dev,
5835f251 357 "dma_pool_alloc %s, %p (corrupted)\n",
5de55b26
MC
358 pool->name, retval);
359 else
5835f251 360 pr_err("dma_pool_alloc %s, %p (corrupted)\n",
5de55b26
MC
361 pool->name, retval);
362
363 /*
364 * Dump the first 4 bytes even if they are not
365 * POOL_POISON_FREED
366 */
367 print_hex_dump(KERN_ERR, "", DUMP_PREFIX_OFFSET, 16, 1,
368 data, pool->size, 1);
369 break;
370 }
371 }
fa23f56d
SS
372 if (!(mem_flags & __GFP_ZERO))
373 memset(retval, POOL_POISON_ALLOCATED, pool->size);
1da177e4 374#endif
e87aa773 375 spin_unlock_irqrestore(&pool->lock, flags);
fa23f56d 376
6471384a 377 if (want_init_on_alloc(mem_flags))
fa23f56d
SS
378 memset(retval, 0, pool->size);
379
1da177e4
LT
380 return retval;
381}
e87aa773 382EXPORT_SYMBOL(dma_pool_alloc);
1da177e4 383
e87aa773 384static struct dma_page *pool_find_page(struct dma_pool *pool, dma_addr_t dma)
1da177e4 385{
e87aa773 386 struct dma_page *page;
1da177e4 387
1da177e4
LT
388 list_for_each_entry(page, &pool->page_list, page_list) {
389 if (dma < page->dma)
390 continue;
676bd991 391 if ((dma - page->dma) < pool->allocation)
84bc227d 392 return page;
1da177e4 393 }
84bc227d 394 return NULL;
1da177e4
LT
395}
396
1da177e4
LT
397/**
398 * dma_pool_free - put block back into dma pool
399 * @pool: the dma pool holding the block
400 * @vaddr: virtual address of block
401 * @dma: dma address of block
402 *
403 * Caller promises neither device nor driver will again touch this block
404 * unless it is first re-allocated.
405 */
e87aa773 406void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma)
1da177e4 407{
e87aa773
MW
408 struct dma_page *page;
409 unsigned long flags;
a35a3455 410 unsigned int offset;
1da177e4 411
84bc227d 412 spin_lock_irqsave(&pool->lock, flags);
e87aa773
MW
413 page = pool_find_page(pool, dma);
414 if (!page) {
84bc227d 415 spin_unlock_irqrestore(&pool->lock, flags);
1da177e4 416 if (pool->dev)
e87aa773
MW
417 dev_err(pool->dev,
418 "dma_pool_free %s, %p/%lx (bad dma)\n",
419 pool->name, vaddr, (unsigned long)dma);
1da177e4 420 else
1170532b 421 pr_err("dma_pool_free %s, %p/%lx (bad dma)\n",
e87aa773 422 pool->name, vaddr, (unsigned long)dma);
1da177e4
LT
423 return;
424 }
425
a35a3455 426 offset = vaddr - page->vaddr;
6471384a
AP
427 if (want_init_on_free())
428 memset(vaddr, 0, pool->size);
b5ee5bef 429#ifdef DMAPOOL_DEBUG
a35a3455 430 if ((dma - page->dma) != offset) {
84bc227d 431 spin_unlock_irqrestore(&pool->lock, flags);
1da177e4 432 if (pool->dev)
e87aa773 433 dev_err(pool->dev,
199eaa05
MC
434 "dma_pool_free %s, %p (bad vaddr)/%pad\n",
435 pool->name, vaddr, &dma);
1da177e4 436 else
199eaa05
MC
437 pr_err("dma_pool_free %s, %p (bad vaddr)/%pad\n",
438 pool->name, vaddr, &dma);
1da177e4
LT
439 return;
440 }
a35a3455
MW
441 {
442 unsigned int chain = page->offset;
443 while (chain < pool->allocation) {
444 if (chain != offset) {
445 chain = *(int *)(page->vaddr + chain);
446 continue;
447 }
84bc227d 448 spin_unlock_irqrestore(&pool->lock, flags);
a35a3455 449 if (pool->dev)
199eaa05
MC
450 dev_err(pool->dev, "dma_pool_free %s, dma %pad already free\n",
451 pool->name, &dma);
a35a3455 452 else
199eaa05
MC
453 pr_err("dma_pool_free %s, dma %pad already free\n",
454 pool->name, &dma);
a35a3455
MW
455 return;
456 }
1da177e4 457 }
e87aa773 458 memset(vaddr, POOL_POISON_FREED, pool->size);
1da177e4
LT
459#endif
460
1da177e4 461 page->in_use--;
a35a3455
MW
462 *(int *)vaddr = page->offset;
463 page->offset = offset;
1da177e4
LT
464 /*
465 * Resist a temptation to do
a35a3455 466 * if (!is_page_busy(page)) pool_free_page(pool, page);
1da177e4
LT
467 * Better have a few empty pages hang around.
468 */
e87aa773 469 spin_unlock_irqrestore(&pool->lock, flags);
1da177e4 470}
e87aa773 471EXPORT_SYMBOL(dma_pool_free);
1da177e4 472
9ac7849e
TH
473/*
474 * Managed DMA pool
475 */
476static void dmam_pool_release(struct device *dev, void *res)
477{
478 struct dma_pool *pool = *(struct dma_pool **)res;
479
480 dma_pool_destroy(pool);
481}
482
483static int dmam_pool_match(struct device *dev, void *res, void *match_data)
484{
485 return *(struct dma_pool **)res == match_data;
486}
487
488/**
489 * dmam_pool_create - Managed dma_pool_create()
490 * @name: name of pool, for diagnostics
491 * @dev: device that will be doing the DMA
492 * @size: size of the blocks in this pool.
493 * @align: alignment requirement for blocks; must be a power of two
494 * @allocation: returned blocks won't cross this boundary (or zero)
495 *
496 * Managed dma_pool_create(). DMA pool created with this function is
497 * automatically destroyed on driver detach.
a862f68a
MR
498 *
499 * Return: a managed dma allocation pool with the requested
500 * characteristics, or %NULL if one can't be created.
9ac7849e
TH
501 */
502struct 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}
e87aa773 519EXPORT_SYMBOL(dmam_pool_create);
9ac7849e
TH
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 */
527void dmam_pool_destroy(struct dma_pool *pool)
528{
529 struct device *dev = pool->dev;
530
172cb4b3 531 WARN_ON(devres_release(dev, dmam_pool_release, dmam_pool_match, pool));
9ac7849e 532}
e87aa773 533EXPORT_SYMBOL(dmam_pool_destroy);