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Diffstat (limited to '')
| -rw-r--r-- | mm/dmapool.c | 524 |
1 files changed, 524 insertions, 0 deletions
diff --git a/mm/dmapool.c b/mm/dmapool.c new file mode 100644 index 0000000000..a151a21e57 --- /dev/null +++ b/mm/dmapool.c @@ -0,0 +1,524 @@ +// 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 across all pages. 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_block { + struct dma_block *next_block; + dma_addr_t dma; +}; + +struct dma_pool { /* the pool */ + struct list_head page_list; + spinlock_t lock; + struct dma_block *next_block; + size_t nr_blocks; + size_t nr_active; + size_t nr_pages; + 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; +}; + +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) +{ + struct dma_pool *pool; + unsigned size; + + size = sysfs_emit(buf, "poolinfo - 0.1\n"); + + mutex_lock(&pools_lock); + list_for_each_entry(pool, &dev->dma_pools, pools) { + /* per-pool info, no real statistics yet */ + size += sysfs_emit_at(buf, size, "%-16s %4zu %4zu %4u %2zu\n", + pool->name, pool->nr_active, + pool->nr_blocks, pool->size, + pool->nr_pages); + } + mutex_unlock(&pools_lock); + + return size; +} + +static DEVICE_ATTR_RO(pools); + +#ifdef DMAPOOL_DEBUG +static void pool_check_block(struct dma_pool *pool, struct dma_block *block, + gfp_t mem_flags) +{ + u8 *data = (void *)block; + int i; + + for (i = sizeof(struct dma_block); i < pool->size; i++) { + if (data[i] == POOL_POISON_FREED) + continue; + dev_err(pool->dev, "%s %s, %p (corrupted)\n", __func__, + pool->name, block); + + /* + * 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(block, POOL_POISON_ALLOCATED, pool->size); +} + +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; +} + +static bool pool_block_err(struct dma_pool *pool, void *vaddr, dma_addr_t dma) +{ + struct dma_block *block = pool->next_block; + struct dma_page *page; + + page = pool_find_page(pool, dma); + if (!page) { + dev_err(pool->dev, "%s %s, %p/%pad (bad dma)\n", + __func__, pool->name, vaddr, &dma); + return true; + } + + while (block) { + if (block != vaddr) { + block = block->next_block; + 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, struct dma_block *block, + gfp_t mem_flags) +{ +} + +static bool pool_block_err(struct dma_pool *pool, void *vaddr, dma_addr_t dma) +{ + if (want_init_on_free()) + memset(vaddr, 0, pool->size); + return false; +} + +static void pool_init_page(struct dma_pool *pool, struct dma_page *page) +{ +} +#endif + +static struct dma_block *pool_block_pop(struct dma_pool *pool) +{ + struct dma_block *block = pool->next_block; + + if (block) { + pool->next_block = block->next_block; + pool->nr_active++; + } + return block; +} + +static void pool_block_push(struct dma_pool *pool, struct dma_block *block, + dma_addr_t dma) +{ + block->dma = dma; + block->next_block = pool->next_block; + pool->next_block = block; +} + + +/** + * 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; + + if (!dev) + return NULL; + + if (align == 0) + align = 1; + else if (align & (align - 1)) + return NULL; + + if (size == 0 || size > INT_MAX) + return NULL; + if (size < sizeof(struct dma_block)) + size = sizeof(struct dma_block); + + 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 = kzalloc(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); + empty = list_empty(&dev->dma_pools); + 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 next_boundary = pool->boundary, offset = 0; + struct dma_block *block, *first = NULL, *last = NULL; + + pool_init_page(pool, page); + while (offset + pool->size <= pool->allocation) { + if (offset + pool->size > next_boundary) { + offset = next_boundary; + next_boundary += pool->boundary; + continue; + } + + block = page->vaddr + offset; + block->dma = page->dma + offset; + block->next_block = NULL; + + if (last) + last->next_block = block; + else + first = block; + last = block; + + offset += pool->size; + pool->nr_blocks++; + } + + last->next_block = pool->next_block; + pool->next_block = first; + + list_add(&page->page_list, &pool->page_list); + pool->nr_pages++; +} + +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) { + kfree(page); + return NULL; + } + + return 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, busy = false; + + if (unlikely(!pool)) + return; + + mutex_lock(&pools_reg_lock); + mutex_lock(&pools_lock); + list_del(&pool->pools); + empty = list_empty(&pool->dev->dma_pools); + mutex_unlock(&pools_lock); + if (empty) + device_remove_file(pool->dev, &dev_attr_pools); + mutex_unlock(&pools_reg_lock); + + if (pool->nr_active) { + dev_err(pool->dev, "%s %s busy\n", __func__, pool->name); + busy = true; + } + + list_for_each_entry_safe(page, tmp, &pool->page_list, page_list) { + if (!busy) + dma_free_coherent(pool->dev, pool->allocation, + page->vaddr, page->dma); + list_del(&page->page_list); + kfree(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) +{ + struct dma_block *block; + struct dma_page *page; + unsigned long flags; + + might_alloc(mem_flags); + + spin_lock_irqsave(&pool->lock, flags); + block = pool_block_pop(pool); + if (!block) { + /* + * 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); + pool_initialise_page(pool, page); + block = pool_block_pop(pool); + } + spin_unlock_irqrestore(&pool->lock, flags); + + *handle = block->dma; + pool_check_block(pool, block, mem_flags); + if (want_init_on_alloc(mem_flags)) + memset(block, 0, pool->size); + + return block; +} +EXPORT_SYMBOL(dma_pool_alloc); + +/** + * 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_block *block = vaddr; + unsigned long flags; + + spin_lock_irqsave(&pool->lock, flags); + if (!pool_block_err(pool, vaddr, dma)) { + pool_block_push(pool, block, dma); + pool->nr_active--; + } + 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); |