1 // SPDX-License-Identifier: GPL-2.0-only
3  * DMA Pool allocator
9  * This allocator returns small blocks of a given size which are DMA-able by
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
17  * least 'size' bytes.  Free blocks are tracked in an unsorted singly-linked
23 #include <linux/dma-mapping.h>
45 	dma_addr_t dma;  member
48 struct dma_pool {		/* the pool */
66 	dma_addr_t dma;  member
74 	struct dma_pool *pool;  in pools_show()  local
77 	size = sysfs_emit(buf, "poolinfo - 0.1\n");  in pools_show()
80 	list_for_each_entry(pool, &dev->dma_pools, pools) {  in pools_show()
81 		/* per-pool info, no real statistics yet */  in pools_show()
82 		size += sysfs_emit_at(buf, size, "%-16s %4zu %4zu %4u %2zu\n",  in pools_show()
83 				      pool->name, pool->nr_active,  in pools_show()
84 				      pool->nr_blocks, pool->size,  in pools_show()
85 				      pool->nr_pages);  in pools_show()
95 static void pool_check_block(struct dma_pool *pool, struct dma_block *block,  in pool_check_block()  argument
101 	for (i = sizeof(struct dma_block); i < pool->size; i++) {  in pool_check_block()
104 		dev_err(pool->dev, "%s %s, %p (corrupted)\n", __func__,  in pool_check_block()
105 			pool->name, block);  in pool_check_block()
112 				data, pool->size, 1);  in pool_check_block()
117 		memset(block, POOL_POISON_ALLOCATED, pool->size);  in pool_check_block()
120 static struct dma_page *pool_find_page(struct dma_pool *pool, dma_addr_t dma)  in pool_find_page()  argument
124 	list_for_each_entry(page, &pool->page_list, page_list) {  in pool_find_page()
125 		if (dma < page->dma)  in pool_find_page()
127 		if ((dma - page->dma) < pool->allocation)  in pool_find_page()
133 static bool pool_block_err(struct dma_pool *pool, void *vaddr, dma_addr_t dma)  in pool_block_err()  argument
135 	struct dma_block *block = pool->next_block;  in pool_block_err()
138 	page = pool_find_page(pool, dma);  in pool_block_err()
140 		dev_err(pool->dev, "%s %s, %p/%pad (bad dma)\n",  in pool_block_err()
141 			__func__, pool->name, vaddr, &dma);  in pool_block_err()
147 			block = block->next_block;  in pool_block_err()
150 		dev_err(pool->dev, "%s %s, dma %pad already free\n",  in pool_block_err()
151 			__func__, pool->name, &dma);  in pool_block_err()
155 	memset(vaddr, POOL_POISON_FREED, pool->size);  in pool_block_err()
159 static void pool_init_page(struct dma_pool *pool, struct dma_page *page)  in pool_init_page()  argument
161 	memset(page->vaddr, POOL_POISON_FREED, pool->allocation);  in pool_init_page()
164 static void pool_check_block(struct dma_pool *pool, struct dma_block *block,  in pool_check_block()  argument
169 static bool pool_block_err(struct dma_pool *pool, void *vaddr, dma_addr_t dma)  in pool_block_err()  argument
172 		memset(vaddr, 0, pool->size);  in pool_block_err()
176 static void pool_init_page(struct dma_pool *pool, struct dma_page *page)  in pool_init_page()  argument
181 static struct dma_block *pool_block_pop(struct dma_pool *pool)  in pool_block_pop()  argument
183 	struct dma_block *block = pool->next_block;  in pool_block_pop()
186 		pool->next_block = block->next_block;  in pool_block_pop()
187 		pool->nr_active++;  in pool_block_pop()
192 static void pool_block_push(struct dma_pool *pool, struct dma_block *block,  in pool_block_push()  argument
193 			    dma_addr_t dma)  in pool_block_push()  argument
195 	block->dma = dma;  in pool_block_push()
196 	block->next_block = pool->next_block;  in pool_block_push()
197 	pool->next_block = block;  in pool_block_push()
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.
212  * DMA mappings, accessible by the device and its driver without using
218  * addressing restrictions on individual DMA transfers, such as not crossing
221  * Return: a dma allocation pool with the requested characteristics, or
236 	else if (align & (align - 1))  in dma_pool_create()
249 	else if ((boundary < size) || (boundary & (boundary - 1)))  in dma_pool_create()
258 	strscpy(retval->name, name, sizeof(retval->name));  in dma_pool_create()
260 	retval->dev = dev;  in dma_pool_create()
262 	INIT_LIST_HEAD(&retval->page_list);  in dma_pool_create()
263 	spin_lock_init(&retval->lock);  in dma_pool_create()
264 	retval->size = size;  in dma_pool_create()
265 	retval->boundary = boundary;  in dma_pool_create()
266 	retval->allocation = allocation;  in dma_pool_create()
267 	INIT_LIST_HEAD(&retval->pools);  in dma_pool_create()
270 	 * pools_lock ensures that the ->dma_pools list does not get corrupted.  in dma_pool_create()
279 	empty = list_empty(&dev->dma_pools);  in dma_pool_create()
280 	list_add(&retval->pools, &dev->dma_pools);  in dma_pool_create()
288 			list_del(&retval->pools);  in dma_pool_create()
300 static void pool_initialise_page(struct dma_pool *pool, struct dma_page *page)  in pool_initialise_page()  argument
302 	unsigned int next_boundary = pool->boundary, offset = 0;  in pool_initialise_page()
305 	pool_init_page(pool, page);  in pool_initialise_page()
306 	while (offset + pool->size <= pool->allocation) {  in pool_initialise_page()
307 		if (offset + pool->size > next_boundary) {  in pool_initialise_page()
309 			next_boundary += pool->boundary;  in pool_initialise_page()
313 		block = page->vaddr + offset;  in pool_initialise_page()
314 		block->dma = page->dma + offset;  in pool_initialise_page()
315 		block->next_block = NULL;  in pool_initialise_page()
318 			last->next_block = block;  in pool_initialise_page()
323 		offset += pool->size;  in pool_initialise_page()
324 		pool->nr_blocks++;  in pool_initialise_page()
327 	last->next_block = pool->next_block;  in pool_initialise_page()
328 	pool->next_block = first;  in pool_initialise_page()
330 	list_add(&page->page_list, &pool->page_list);  in pool_initialise_page()
331 	pool->nr_pages++;  in pool_initialise_page()
334 static struct dma_page *pool_alloc_page(struct dma_pool *pool, gfp_t mem_flags)  in pool_alloc_page()  argument
342 	page->vaddr = dma_alloc_coherent(pool->dev, pool->allocation,  in pool_alloc_page()
343 					 &page->dma, mem_flags);  in pool_alloc_page()
344 	if (!page->vaddr) {  in pool_alloc_page()
353  * dma_pool_destroy - destroys a pool of dma memory blocks.
354  * @pool: dma pool that will be destroyed
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.
360 void dma_pool_destroy(struct dma_pool *pool)  in dma_pool_destroy()  argument
365 	if (unlikely(!pool))  in dma_pool_destroy()
370 	list_del(&pool->pools);  in dma_pool_destroy()
371 	empty = list_empty(&pool->dev->dma_pools);  in dma_pool_destroy()
374 		device_remove_file(pool->dev, &dev_attr_pools);  in dma_pool_destroy()
377 	if (pool->nr_active) {  in dma_pool_destroy()
378 		dev_err(pool->dev, "%s %s busy\n", __func__, pool->name);  in dma_pool_destroy()
382 	list_for_each_entry_safe(page, tmp, &pool->page_list, page_list) {  in dma_pool_destroy()
384 			dma_free_coherent(pool->dev, pool->allocation,  in dma_pool_destroy()
385 					  page->vaddr, page->dma);  in dma_pool_destroy()
386 		list_del(&page->page_list);  in dma_pool_destroy()
390 	kfree(pool);  in dma_pool_destroy()
395  * dma_pool_alloc - get a block of consistent memory
396  * @pool: dma pool that will produce the block
398  * @handle: pointer to dma address of block
401  * and reports its dma address through the handle.
404 void *dma_pool_alloc(struct dma_pool *pool, gfp_t mem_flags,  in dma_pool_alloc()  argument
413 	spin_lock_irqsave(&pool->lock, flags);  in dma_pool_alloc()
414 	block = pool_block_pop(pool);  in dma_pool_alloc()
418 		 * &pool->lock  in dma_pool_alloc()
420 		spin_unlock_irqrestore(&pool->lock, flags);  in dma_pool_alloc()
422 		page = pool_alloc_page(pool, mem_flags & (~__GFP_ZERO));  in dma_pool_alloc()
426 		spin_lock_irqsave(&pool->lock, flags);  in dma_pool_alloc()
427 		pool_initialise_page(pool, page);  in dma_pool_alloc()
428 		block = pool_block_pop(pool);  in dma_pool_alloc()
430 	spin_unlock_irqrestore(&pool->lock, flags);  in dma_pool_alloc()
432 	*handle = block->dma;  in dma_pool_alloc()
433 	pool_check_block(pool, block, mem_flags);  in dma_pool_alloc()
435 		memset(block, 0, pool->size);  in dma_pool_alloc()
442  * dma_pool_free - put block back into dma pool
443  * @pool: the dma pool holding the block
445  * @dma: dma address of block
448  * unless it is first re-allocated.
450 void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma)  in dma_pool_free()  argument
455 	spin_lock_irqsave(&pool->lock, flags);  in dma_pool_free()
456 	if (!pool_block_err(pool, vaddr, dma)) {  in dma_pool_free()
457 		pool_block_push(pool, block, dma);  in dma_pool_free()
458 		pool->nr_active--;  in dma_pool_free()
460 	spin_unlock_irqrestore(&pool->lock, flags);  in dma_pool_free()
465  * Managed DMA pool
469 	struct dma_pool *pool = *(struct dma_pool **)res;  in dmam_pool_release()  local
471 	dma_pool_destroy(pool);  in dmam_pool_release()
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.
487  * Managed dma_pool_create().  DMA pool created with this function is
490  * Return: a managed dma allocation pool with the requested
496 	struct dma_pool **ptr, *pool;  in dmam_pool_create()  local
502 	pool = *ptr = dma_pool_create(name, dev, size, align, allocation);  in dmam_pool_create()
503 	if (pool)  in dmam_pool_create()
508 	return pool;  in dmam_pool_create()
513  * dmam_pool_destroy - Managed dma_pool_destroy()
514  * @pool: dma pool that will be destroyed
518 void dmam_pool_destroy(struct dma_pool *pool)  in dmam_pool_destroy()  argument
520 	struct device *dev = pool->dev;  in dmam_pool_destroy()
522 	WARN_ON(devres_release(dev, dmam_pool_release, dmam_pool_match, pool));  in dmam_pool_destroy()