| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * DMA Pool allocator |
| * |
| * Copyright 2001 David Brownell |
| * Copyright 2007 Intel Corporation |
| * Author: Matthew Wilcox <willy@linux.intel.com> |
| * |
| * This allocator returns small blocks of a given size which are DMA-able by |
| * the given device. It uses the dma_alloc_coherent page allocator to get |
| * new pages, then splits them up into blocks of the required size. |
| * Many older drivers still have their own code to do this. |
| * |
| * The current design of this allocator is fairly simple. The pool is |
| * represented by the 'struct dma_pool' which keeps a doubly-linked list of |
| * allocated pages. Each page in the page_list is split into blocks of at |
| * least 'size' bytes. Free blocks are tracked in an unsorted singly-linked |
| * list of free blocks within the page. Used blocks aren't tracked, but we |
| * keep a count of how many are currently allocated from each page. |
| */ |
| |
| #include <linux/device.h> |
| #include <linux/dma-mapping.h> |
| #include <linux/dmapool.h> |
| #include <linux/kernel.h> |
| #include <linux/list.h> |
| #include <linux/export.h> |
| #include <linux/mutex.h> |
| #include <linux/poison.h> |
| #include <linux/sched.h> |
| #include <linux/sched/mm.h> |
| #include <linux/slab.h> |
| #include <linux/stat.h> |
| #include <linux/spinlock.h> |
| #include <linux/string.h> |
| #include <linux/types.h> |
| #include <linux/wait.h> |
| |
| #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB_DEBUG_ON) |
| #define DMAPOOL_DEBUG 1 |
| #endif |
| |
| struct dma_pool { /* the pool */ |
| struct list_head page_list; |
| spinlock_t lock; |
| struct device *dev; |
| unsigned int size; |
| unsigned int allocation; |
| unsigned int boundary; |
| char name[32]; |
| struct list_head pools; |
| }; |
| |
| struct dma_page { /* cacheable header for 'allocation' bytes */ |
| struct list_head page_list; |
| void *vaddr; |
| dma_addr_t dma; |
| unsigned int in_use; |
| unsigned int offset; |
| }; |
| |
| static DEFINE_MUTEX(pools_lock); |
| static DEFINE_MUTEX(pools_reg_lock); |
| |
| static ssize_t pools_show(struct device *dev, struct device_attribute *attr, char *buf) |
| { |
| int size; |
| struct dma_page *page; |
| struct dma_pool *pool; |
| |
| size = sysfs_emit(buf, "poolinfo - 0.1\n"); |
| |
| mutex_lock(&pools_lock); |
| list_for_each_entry(pool, &dev->dma_pools, pools) { |
| unsigned pages = 0; |
| size_t blocks = 0; |
| |
| spin_lock_irq(&pool->lock); |
| list_for_each_entry(page, &pool->page_list, page_list) { |
| pages++; |
| blocks += page->in_use; |
| } |
| spin_unlock_irq(&pool->lock); |
| |
| /* per-pool info, no real statistics yet */ |
| size += sysfs_emit_at(buf, size, "%-16s %4zu %4zu %4u %2u\n", |
| pool->name, blocks, |
| (size_t) pages * |
| (pool->allocation / pool->size), |
| pool->size, pages); |
| } |
| mutex_unlock(&pools_lock); |
| |
| return size; |
| } |
| |
| static DEVICE_ATTR_RO(pools); |
| |
| #ifdef DMAPOOL_DEBUG |
| static void pool_check_block(struct dma_pool *pool, void *retval, |
| unsigned int offset, gfp_t mem_flags) |
| { |
| int i; |
| u8 *data = retval; |
| /* page->offset is stored in first 4 bytes */ |
| for (i = sizeof(offset); i < pool->size; i++) { |
| if (data[i] == POOL_POISON_FREED) |
| continue; |
| dev_err(pool->dev, "%s %s, %p (corrupted)\n", |
| __func__, pool->name, retval); |
| |
| /* |
| * Dump the first 4 bytes even if they are not |
| * POOL_POISON_FREED |
| */ |
| print_hex_dump(KERN_ERR, "", DUMP_PREFIX_OFFSET, 16, 1, |
| data, pool->size, 1); |
| break; |
| } |
| if (!want_init_on_alloc(mem_flags)) |
| memset(retval, POOL_POISON_ALLOCATED, pool->size); |
| } |
| |
| static bool pool_page_err(struct dma_pool *pool, struct dma_page *page, |
| void *vaddr, dma_addr_t dma) |
| { |
| unsigned int offset = vaddr - page->vaddr; |
| unsigned int chain = page->offset; |
| |
| if ((dma - page->dma) != offset) { |
| dev_err(pool->dev, "%s %s, %p (bad vaddr)/%pad\n", |
| __func__, pool->name, vaddr, &dma); |
| return true; |
| } |
| |
| while (chain < pool->allocation) { |
| if (chain != offset) { |
| chain = *(int *)(page->vaddr + chain); |
| continue; |
| } |
| dev_err(pool->dev, "%s %s, dma %pad already free\n", |
| __func__, pool->name, &dma); |
| return true; |
| } |
| memset(vaddr, POOL_POISON_FREED, pool->size); |
| return false; |
| } |
| |
| static void pool_init_page(struct dma_pool *pool, struct dma_page *page) |
| { |
| memset(page->vaddr, POOL_POISON_FREED, pool->allocation); |
| } |
| #else |
| static void pool_check_block(struct dma_pool *pool, void *retval, |
| unsigned int offset, gfp_t mem_flags) |
| |
| { |
| } |
| |
| static bool pool_page_err(struct dma_pool *pool, struct dma_page *page, |
| void *vaddr, dma_addr_t dma) |
| { |
| return false; |
| } |
| |
| static void pool_init_page(struct dma_pool *pool, struct dma_page *page) |
| { |
| } |
| #endif |
| |
| /** |
| * dma_pool_create - Creates a pool of consistent memory blocks, for dma. |
| * @name: name of pool, for diagnostics |
| * @dev: device that will be doing the DMA |
| * @size: size of the blocks in this pool. |
| * @align: alignment requirement for blocks; must be a power of two |
| * @boundary: returned blocks won't cross this power of two boundary |
| * Context: not in_interrupt() |
| * |
| * Given one of these pools, dma_pool_alloc() |
| * may be used to allocate memory. Such memory will all have "consistent" |
| * DMA mappings, accessible by the device and its driver without using |
| * cache flushing primitives. The actual size of blocks allocated may be |
| * larger than requested because of alignment. |
| * |
| * If @boundary is nonzero, objects returned from dma_pool_alloc() won't |
| * cross that size boundary. This is useful for devices which have |
| * addressing restrictions on individual DMA transfers, such as not crossing |
| * boundaries of 4KBytes. |
| * |
| * Return: a dma allocation pool with the requested characteristics, or |
| * %NULL if one can't be created. |
| */ |
| struct dma_pool *dma_pool_create(const char *name, struct device *dev, |
| size_t size, size_t align, size_t boundary) |
| { |
| struct dma_pool *retval; |
| size_t allocation; |
| bool empty = false; |
| |
| if (!dev) |
| return NULL; |
| |
| if (align == 0) |
| align = 1; |
| else if (align & (align - 1)) |
| return NULL; |
| |
| if (size == 0 || size > INT_MAX) |
| return NULL; |
| else if (size < 4) |
| size = 4; |
| |
| size = ALIGN(size, align); |
| allocation = max_t(size_t, size, PAGE_SIZE); |
| |
| if (!boundary) |
| boundary = allocation; |
| else if ((boundary < size) || (boundary & (boundary - 1))) |
| return NULL; |
| |
| boundary = min(boundary, allocation); |
| |
| retval = kmalloc(sizeof(*retval), GFP_KERNEL); |
| if (!retval) |
| return retval; |
| |
| strscpy(retval->name, name, sizeof(retval->name)); |
| |
| retval->dev = dev; |
| |
| INIT_LIST_HEAD(&retval->page_list); |
| spin_lock_init(&retval->lock); |
| retval->size = size; |
| retval->boundary = boundary; |
| retval->allocation = allocation; |
| |
| INIT_LIST_HEAD(&retval->pools); |
| |
| /* |
| * pools_lock ensures that the ->dma_pools list does not get corrupted. |
| * pools_reg_lock ensures that there is not a race between |
| * dma_pool_create() and dma_pool_destroy() or within dma_pool_create() |
| * when the first invocation of dma_pool_create() failed on |
| * device_create_file() and the second assumes that it has been done (I |
| * know it is a short window). |
| */ |
| mutex_lock(&pools_reg_lock); |
| mutex_lock(&pools_lock); |
| if (list_empty(&dev->dma_pools)) |
| empty = true; |
| list_add(&retval->pools, &dev->dma_pools); |
| mutex_unlock(&pools_lock); |
| if (empty) { |
| int err; |
| |
| err = device_create_file(dev, &dev_attr_pools); |
| if (err) { |
| mutex_lock(&pools_lock); |
| list_del(&retval->pools); |
| mutex_unlock(&pools_lock); |
| mutex_unlock(&pools_reg_lock); |
| kfree(retval); |
| return NULL; |
| } |
| } |
| mutex_unlock(&pools_reg_lock); |
| return retval; |
| } |
| EXPORT_SYMBOL(dma_pool_create); |
| |
| static void pool_initialise_page(struct dma_pool *pool, struct dma_page *page) |
| { |
| unsigned int offset = 0; |
| unsigned int next_boundary = pool->boundary; |
| |
| do { |
| unsigned int next = offset + pool->size; |
| if (unlikely((next + pool->size) >= next_boundary)) { |
| next = next_boundary; |
| next_boundary += pool->boundary; |
| } |
| *(int *)(page->vaddr + offset) = next; |
| offset = next; |
| } while (offset < pool->allocation); |
| } |
| |
| static struct dma_page *pool_alloc_page(struct dma_pool *pool, gfp_t mem_flags) |
| { |
| struct dma_page *page; |
| |
| page = kmalloc(sizeof(*page), mem_flags); |
| if (!page) |
| return NULL; |
| page->vaddr = dma_alloc_coherent(pool->dev, pool->allocation, |
| &page->dma, mem_flags); |
| if (page->vaddr) { |
| pool_init_page(pool, page); |
| pool_initialise_page(pool, page); |
| page->in_use = 0; |
| page->offset = 0; |
| } else { |
| kfree(page); |
| page = NULL; |
| } |
| return page; |
| } |
| |
| static inline bool is_page_busy(struct dma_page *page) |
| { |
| return page->in_use != 0; |
| } |
| |
| static void pool_free_page(struct dma_pool *pool, struct dma_page *page) |
| { |
| dma_addr_t dma = page->dma; |
| |
| pool_init_page(pool, page); |
| dma_free_coherent(pool->dev, pool->allocation, page->vaddr, dma); |
| list_del(&page->page_list); |
| kfree(page); |
| } |
| |
| /** |
| * dma_pool_destroy - destroys a pool of dma memory blocks. |
| * @pool: dma pool that will be destroyed |
| * Context: !in_interrupt() |
| * |
| * Caller guarantees that no more memory from the pool is in use, |
| * and that nothing will try to use the pool after this call. |
| */ |
| void dma_pool_destroy(struct dma_pool *pool) |
| { |
| struct dma_page *page, *tmp; |
| bool empty = false; |
| |
| if (unlikely(!pool)) |
| return; |
| |
| mutex_lock(&pools_reg_lock); |
| mutex_lock(&pools_lock); |
| list_del(&pool->pools); |
| if (list_empty(&pool->dev->dma_pools)) |
| empty = true; |
| mutex_unlock(&pools_lock); |
| if (empty) |
| device_remove_file(pool->dev, &dev_attr_pools); |
| mutex_unlock(&pools_reg_lock); |
| |
| list_for_each_entry_safe(page, tmp, &pool->page_list, page_list) { |
| if (is_page_busy(page)) { |
| dev_err(pool->dev, "%s %s, %p busy\n", __func__, |
| pool->name, page->vaddr); |
| /* leak the still-in-use consistent memory */ |
| list_del(&page->page_list); |
| kfree(page); |
| } else |
| pool_free_page(pool, page); |
| } |
| |
| kfree(pool); |
| } |
| EXPORT_SYMBOL(dma_pool_destroy); |
| |
| /** |
| * dma_pool_alloc - get a block of consistent memory |
| * @pool: dma pool that will produce the block |
| * @mem_flags: GFP_* bitmask |
| * @handle: pointer to dma address of block |
| * |
| * Return: the kernel virtual address of a currently unused block, |
| * and reports its dma address through the handle. |
| * If such a memory block can't be allocated, %NULL is returned. |
| */ |
| void *dma_pool_alloc(struct dma_pool *pool, gfp_t mem_flags, |
| dma_addr_t *handle) |
| { |
| unsigned long flags; |
| struct dma_page *page; |
| unsigned int offset; |
| void *retval; |
| |
| might_alloc(mem_flags); |
| |
| spin_lock_irqsave(&pool->lock, flags); |
| list_for_each_entry(page, &pool->page_list, page_list) { |
| if (page->offset < pool->allocation) |
| goto ready; |
| } |
| |
| /* pool_alloc_page() might sleep, so temporarily drop &pool->lock */ |
| spin_unlock_irqrestore(&pool->lock, flags); |
| |
| page = pool_alloc_page(pool, mem_flags & (~__GFP_ZERO)); |
| if (!page) |
| return NULL; |
| |
| spin_lock_irqsave(&pool->lock, flags); |
| |
| list_add(&page->page_list, &pool->page_list); |
| ready: |
| page->in_use++; |
| offset = page->offset; |
| page->offset = *(int *)(page->vaddr + offset); |
| retval = offset + page->vaddr; |
| *handle = offset + page->dma; |
| pool_check_block(pool, retval, offset, mem_flags); |
| spin_unlock_irqrestore(&pool->lock, flags); |
| |
| if (want_init_on_alloc(mem_flags)) |
| memset(retval, 0, pool->size); |
| |
| return retval; |
| } |
| EXPORT_SYMBOL(dma_pool_alloc); |
| |
| static struct dma_page *pool_find_page(struct dma_pool *pool, dma_addr_t dma) |
| { |
| struct dma_page *page; |
| |
| list_for_each_entry(page, &pool->page_list, page_list) { |
| if (dma < page->dma) |
| continue; |
| if ((dma - page->dma) < pool->allocation) |
| return page; |
| } |
| return NULL; |
| } |
| |
| /** |
| * dma_pool_free - put block back into dma pool |
| * @pool: the dma pool holding the block |
| * @vaddr: virtual address of block |
| * @dma: dma address of block |
| * |
| * Caller promises neither device nor driver will again touch this block |
| * unless it is first re-allocated. |
| */ |
| void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma) |
| { |
| struct dma_page *page; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&pool->lock, flags); |
| page = pool_find_page(pool, dma); |
| if (!page) { |
| spin_unlock_irqrestore(&pool->lock, flags); |
| dev_err(pool->dev, "%s %s, %p/%pad (bad dma)\n", |
| __func__, pool->name, vaddr, &dma); |
| return; |
| } |
| |
| if (want_init_on_free()) |
| memset(vaddr, 0, pool->size); |
| if (pool_page_err(pool, page, vaddr, dma)) { |
| spin_unlock_irqrestore(&pool->lock, flags); |
| return; |
| } |
| |
| page->in_use--; |
| *(int *)vaddr = page->offset; |
| page->offset = vaddr - page->vaddr; |
| /* |
| * Resist a temptation to do |
| * if (!is_page_busy(page)) pool_free_page(pool, page); |
| * Better have a few empty pages hang around. |
| */ |
| spin_unlock_irqrestore(&pool->lock, flags); |
| } |
| EXPORT_SYMBOL(dma_pool_free); |
| |
| /* |
| * Managed DMA pool |
| */ |
| static void dmam_pool_release(struct device *dev, void *res) |
| { |
| struct dma_pool *pool = *(struct dma_pool **)res; |
| |
| dma_pool_destroy(pool); |
| } |
| |
| static int dmam_pool_match(struct device *dev, void *res, void *match_data) |
| { |
| return *(struct dma_pool **)res == match_data; |
| } |
| |
| /** |
| * dmam_pool_create - Managed dma_pool_create() |
| * @name: name of pool, for diagnostics |
| * @dev: device that will be doing the DMA |
| * @size: size of the blocks in this pool. |
| * @align: alignment requirement for blocks; must be a power of two |
| * @allocation: returned blocks won't cross this boundary (or zero) |
| * |
| * Managed dma_pool_create(). DMA pool created with this function is |
| * automatically destroyed on driver detach. |
| * |
| * Return: a managed dma allocation pool with the requested |
| * characteristics, or %NULL if one can't be created. |
| */ |
| struct dma_pool *dmam_pool_create(const char *name, struct device *dev, |
| size_t size, size_t align, size_t allocation) |
| { |
| struct dma_pool **ptr, *pool; |
| |
| ptr = devres_alloc(dmam_pool_release, sizeof(*ptr), GFP_KERNEL); |
| if (!ptr) |
| return NULL; |
| |
| pool = *ptr = dma_pool_create(name, dev, size, align, allocation); |
| if (pool) |
| devres_add(dev, ptr); |
| else |
| devres_free(ptr); |
| |
| return pool; |
| } |
| EXPORT_SYMBOL(dmam_pool_create); |
| |
| /** |
| * dmam_pool_destroy - Managed dma_pool_destroy() |
| * @pool: dma pool that will be destroyed |
| * |
| * Managed dma_pool_destroy(). |
| */ |
| void dmam_pool_destroy(struct dma_pool *pool) |
| { |
| struct device *dev = pool->dev; |
| |
| WARN_ON(devres_release(dev, dmam_pool_release, dmam_pool_match, pool)); |
| } |
| EXPORT_SYMBOL(dmam_pool_destroy); |