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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * DMA Pool allocator4 *5 * Copyright 2001 David Brownell6 * Copyright 2007 Intel Corporation7 * Author: Matthew Wilcox <willy@linux.intel.com>8 *9 * This allocator returns small blocks of a given size which are DMA-able by10 * the given device. It uses the dma_alloc_coherent page allocator to get11 * 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 is15 * represented by the 'struct dma_pool' which keeps a doubly-linked list of16 * allocated pages. Each page in the page_list is split into blocks of at17 * least 'size' bytes. Free blocks are tracked in an unsorted singly-linked18 * list of free blocks across all pages. Used blocks aren't tracked, but we19 * 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_ON40#define DMAPOOL_DEBUG 141#endif42 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_DEBUG95static 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 not109 * POOL_POISON_FREED110 */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#else164static 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#endif180 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 diagnostics204 * @dev: device that will be doing the DMA205 * @size: size of the blocks in this pool.206 * @align: alignment requirement for blocks; must be a power of two207 * @boundary: returned blocks won't cross this power of two boundary208 * 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 using213 * cache flushing primitives. The actual size of blocks allocated may be214 * larger than requested because of alignment.215 *216 * If @boundary is nonzero, objects returned from dma_pool_alloc() won't217 * cross that size boundary. This is useful for devices which have218 * addressing restrictions on individual DMA transfers, such as not crossing219 * boundaries of 4KBytes.220 *221 * Return: a dma allocation pool with the requested characteristics, or222 * %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 between272 * dma_pool_create() and dma_pool_destroy() or within dma_pool_create()273 * when the first invocation of dma_pool_create() failed on274 * device_create_file() and the second assumes that it has been done (I275 * 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 else320 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 destroyed355 * 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 memory396 * @pool: dma pool that will produce the block397 * @mem_flags: GFP_* bitmask398 * @handle: pointer to dma address of block399 *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 drop418 * &pool->lock419 */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 pool443 * @pool: the dma pool holding the block444 * @vaddr: virtual address of block445 * @dma: dma address of block446 *447 * Caller promises neither device nor driver will again touch this block448 * 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 pool466 */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 diagnostics482 * @dev: device that will be doing the DMA483 * @size: size of the blocks in this pool.484 * @align: alignment requirement for blocks; must be a power of two485 * @allocation: returned blocks won't cross this boundary (or zero)486 *487 * Managed dma_pool_create(). DMA pool created with this function is488 * automatically destroyed on driver detach.489 *490 * Return: a managed dma allocation pool with the requested491 * 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 else506 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 destroyed515 *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);525