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530 lines
14 KiB
530 lines
14 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* DMA Pool allocator |
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* |
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* Copyright 2001 David Brownell |
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* Copyright 2007 Intel Corporation |
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* Author: Matthew Wilcox <[email protected]> |
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* |
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* This allocator returns small blocks of a given size which are DMA-able by |
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* the given device. It uses the dma_alloc_coherent page allocator to get |
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* new pages, then splits them up into blocks of the required size. |
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* Many older drivers still have their own code to do this. |
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* |
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* The current design of this allocator is fairly simple. The pool is |
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* represented by the 'struct dma_pool' which keeps a doubly-linked list of |
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* allocated pages. Each page in the page_list is split into blocks of at |
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* least 'size' bytes. Free blocks are tracked in an unsorted singly-linked |
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* list of free blocks within the page. Used blocks aren't tracked, but we |
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* keep a count of how many are currently allocated from each page. |
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*/ |
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#include <linux/device.h> |
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#include <linux/dma-mapping.h> |
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#include <linux/dmapool.h> |
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#include <linux/kernel.h> |
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#include <linux/list.h> |
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#include <linux/export.h> |
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#include <linux/mutex.h> |
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#include <linux/poison.h> |
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#include <linux/sched.h> |
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#include <linux/sched/mm.h> |
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#include <linux/slab.h> |
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#include <linux/stat.h> |
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#include <linux/spinlock.h> |
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#include <linux/string.h> |
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#include <linux/types.h> |
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#include <linux/wait.h> |
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#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB_DEBUG_ON) |
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#define DMAPOOL_DEBUG 1 |
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#endif |
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struct dma_pool { /* the pool */ |
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struct list_head page_list; |
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spinlock_t lock; |
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size_t size; |
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struct device *dev; |
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size_t allocation; |
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size_t boundary; |
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char name[32]; |
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struct list_head pools; |
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}; |
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struct dma_page { /* cacheable header for 'allocation' bytes */ |
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struct list_head page_list; |
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void *vaddr; |
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dma_addr_t dma; |
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unsigned int in_use; |
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unsigned int offset; |
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}; |
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static DEFINE_MUTEX(pools_lock); |
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static DEFINE_MUTEX(pools_reg_lock); |
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static ssize_t |
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show_pools(struct device *dev, struct device_attribute *attr, char *buf) |
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{ |
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unsigned temp; |
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unsigned size; |
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char *next; |
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struct dma_page *page; |
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struct dma_pool *pool; |
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next = buf; |
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size = PAGE_SIZE; |
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temp = scnprintf(next, size, "poolinfo - 0.1\n"); |
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size -= temp; |
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next += temp; |
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mutex_lock(&pools_lock); |
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list_for_each_entry(pool, &dev->dma_pools, pools) { |
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unsigned pages = 0; |
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unsigned blocks = 0; |
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spin_lock_irq(&pool->lock); |
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list_for_each_entry(page, &pool->page_list, page_list) { |
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pages++; |
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blocks += page->in_use; |
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} |
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spin_unlock_irq(&pool->lock); |
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/* per-pool info, no real statistics yet */ |
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temp = scnprintf(next, size, "%-16s %4u %4zu %4zu %2u\n", |
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pool->name, blocks, |
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pages * (pool->allocation / pool->size), |
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pool->size, pages); |
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size -= temp; |
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next += temp; |
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} |
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mutex_unlock(&pools_lock); |
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return PAGE_SIZE - size; |
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} |
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static DEVICE_ATTR(pools, 0444, show_pools, NULL); |
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|
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/** |
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* dma_pool_create - Creates a pool of consistent memory blocks, for dma. |
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* @name: name of pool, for diagnostics |
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* @dev: device that will be doing the DMA |
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* @size: size of the blocks in this pool. |
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* @align: alignment requirement for blocks; must be a power of two |
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* @boundary: returned blocks won't cross this power of two boundary |
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* Context: not in_interrupt() |
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* |
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* Given one of these pools, dma_pool_alloc() |
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* may be used to allocate memory. Such memory will all have "consistent" |
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* DMA mappings, accessible by the device and its driver without using |
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* cache flushing primitives. The actual size of blocks allocated may be |
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* larger than requested because of alignment. |
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* |
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* If @boundary is nonzero, objects returned from dma_pool_alloc() won't |
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* cross that size boundary. This is useful for devices which have |
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* addressing restrictions on individual DMA transfers, such as not crossing |
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* boundaries of 4KBytes. |
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* |
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* Return: a dma allocation pool with the requested characteristics, or |
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* %NULL if one can't be created. |
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*/ |
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struct dma_pool *dma_pool_create(const char *name, struct device *dev, |
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size_t size, size_t align, size_t boundary) |
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{ |
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struct dma_pool *retval; |
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size_t allocation; |
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bool empty = false; |
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if (align == 0) |
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align = 1; |
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else if (align & (align - 1)) |
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return NULL; |
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if (size == 0) |
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return NULL; |
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else if (size < 4) |
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size = 4; |
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size = ALIGN(size, align); |
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allocation = max_t(size_t, size, PAGE_SIZE); |
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if (!boundary) |
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boundary = allocation; |
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else if ((boundary < size) || (boundary & (boundary - 1))) |
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return NULL; |
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retval = kmalloc_node(sizeof(*retval), GFP_KERNEL, dev_to_node(dev)); |
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if (!retval) |
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return retval; |
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strlcpy(retval->name, name, sizeof(retval->name)); |
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retval->dev = dev; |
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INIT_LIST_HEAD(&retval->page_list); |
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spin_lock_init(&retval->lock); |
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retval->size = size; |
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retval->boundary = boundary; |
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retval->allocation = allocation; |
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INIT_LIST_HEAD(&retval->pools); |
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/* |
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* pools_lock ensures that the ->dma_pools list does not get corrupted. |
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* pools_reg_lock ensures that there is not a race between |
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* dma_pool_create() and dma_pool_destroy() or within dma_pool_create() |
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* when the first invocation of dma_pool_create() failed on |
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* device_create_file() and the second assumes that it has been done (I |
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* know it is a short window). |
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*/ |
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mutex_lock(&pools_reg_lock); |
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mutex_lock(&pools_lock); |
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if (list_empty(&dev->dma_pools)) |
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empty = true; |
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list_add(&retval->pools, &dev->dma_pools); |
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mutex_unlock(&pools_lock); |
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if (empty) { |
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int err; |
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err = device_create_file(dev, &dev_attr_pools); |
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if (err) { |
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mutex_lock(&pools_lock); |
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list_del(&retval->pools); |
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mutex_unlock(&pools_lock); |
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mutex_unlock(&pools_reg_lock); |
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kfree(retval); |
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return NULL; |
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} |
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} |
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mutex_unlock(&pools_reg_lock); |
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return retval; |
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} |
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EXPORT_SYMBOL(dma_pool_create); |
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static void pool_initialise_page(struct dma_pool *pool, struct dma_page *page) |
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{ |
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unsigned int offset = 0; |
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unsigned int next_boundary = pool->boundary; |
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do { |
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unsigned int next = offset + pool->size; |
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if (unlikely((next + pool->size) >= next_boundary)) { |
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next = next_boundary; |
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next_boundary += pool->boundary; |
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} |
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*(int *)(page->vaddr + offset) = next; |
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offset = next; |
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} while (offset < pool->allocation); |
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} |
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static struct dma_page *pool_alloc_page(struct dma_pool *pool, gfp_t mem_flags) |
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{ |
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struct dma_page *page; |
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page = kmalloc(sizeof(*page), mem_flags); |
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if (!page) |
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return NULL; |
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page->vaddr = dma_alloc_coherent(pool->dev, pool->allocation, |
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&page->dma, mem_flags); |
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if (page->vaddr) { |
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#ifdef DMAPOOL_DEBUG |
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memset(page->vaddr, POOL_POISON_FREED, pool->allocation); |
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#endif |
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pool_initialise_page(pool, page); |
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page->in_use = 0; |
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page->offset = 0; |
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} else { |
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kfree(page); |
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page = NULL; |
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} |
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return page; |
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} |
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static inline bool is_page_busy(struct dma_page *page) |
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{ |
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return page->in_use != 0; |
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} |
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static void pool_free_page(struct dma_pool *pool, struct dma_page *page) |
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{ |
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dma_addr_t dma = page->dma; |
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#ifdef DMAPOOL_DEBUG |
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memset(page->vaddr, POOL_POISON_FREED, pool->allocation); |
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#endif |
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dma_free_coherent(pool->dev, pool->allocation, page->vaddr, dma); |
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list_del(&page->page_list); |
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kfree(page); |
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} |
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/** |
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* dma_pool_destroy - destroys a pool of dma memory blocks. |
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* @pool: dma pool that will be destroyed |
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* Context: !in_interrupt() |
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* |
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* Caller guarantees that no more memory from the pool is in use, |
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* and that nothing will try to use the pool after this call. |
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*/ |
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void dma_pool_destroy(struct dma_pool *pool) |
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{ |
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struct dma_page *page, *tmp; |
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bool empty = false; |
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if (unlikely(!pool)) |
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return; |
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mutex_lock(&pools_reg_lock); |
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mutex_lock(&pools_lock); |
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list_del(&pool->pools); |
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if (pool->dev && list_empty(&pool->dev->dma_pools)) |
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empty = true; |
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mutex_unlock(&pools_lock); |
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if (empty) |
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device_remove_file(pool->dev, &dev_attr_pools); |
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mutex_unlock(&pools_reg_lock); |
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list_for_each_entry_safe(page, tmp, &pool->page_list, page_list) { |
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if (is_page_busy(page)) { |
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if (pool->dev) |
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dev_err(pool->dev, "%s %s, %p busy\n", __func__, |
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pool->name, page->vaddr); |
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else |
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pr_err("%s %s, %p busy\n", __func__, |
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pool->name, page->vaddr); |
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/* leak the still-in-use consistent memory */ |
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list_del(&page->page_list); |
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kfree(page); |
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} else |
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pool_free_page(pool, page); |
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} |
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kfree(pool); |
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} |
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EXPORT_SYMBOL(dma_pool_destroy); |
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/** |
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* dma_pool_alloc - get a block of consistent memory |
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* @pool: dma pool that will produce the block |
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* @mem_flags: GFP_* bitmask |
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* @handle: pointer to dma address of block |
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* |
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* Return: the kernel virtual address of a currently unused block, |
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* and reports its dma address through the handle. |
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* If such a memory block can't be allocated, %NULL is returned. |
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*/ |
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void *dma_pool_alloc(struct dma_pool *pool, gfp_t mem_flags, |
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dma_addr_t *handle) |
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{ |
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unsigned long flags; |
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struct dma_page *page; |
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size_t offset; |
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void *retval; |
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might_alloc(mem_flags); |
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spin_lock_irqsave(&pool->lock, flags); |
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list_for_each_entry(page, &pool->page_list, page_list) { |
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if (page->offset < pool->allocation) |
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goto ready; |
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} |
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/* pool_alloc_page() might sleep, so temporarily drop &pool->lock */ |
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spin_unlock_irqrestore(&pool->lock, flags); |
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page = pool_alloc_page(pool, mem_flags & (~__GFP_ZERO)); |
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if (!page) |
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return NULL; |
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spin_lock_irqsave(&pool->lock, flags); |
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list_add(&page->page_list, &pool->page_list); |
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ready: |
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page->in_use++; |
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offset = page->offset; |
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page->offset = *(int *)(page->vaddr + offset); |
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retval = offset + page->vaddr; |
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*handle = offset + page->dma; |
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#ifdef DMAPOOL_DEBUG |
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{ |
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int i; |
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u8 *data = retval; |
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/* page->offset is stored in first 4 bytes */ |
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for (i = sizeof(page->offset); i < pool->size; i++) { |
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if (data[i] == POOL_POISON_FREED) |
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continue; |
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if (pool->dev) |
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dev_err(pool->dev, "%s %s, %p (corrupted)\n", |
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__func__, pool->name, retval); |
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else |
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pr_err("%s %s, %p (corrupted)\n", |
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__func__, pool->name, retval); |
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/* |
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* Dump the first 4 bytes even if they are not |
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* POOL_POISON_FREED |
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*/ |
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print_hex_dump(KERN_ERR, "", DUMP_PREFIX_OFFSET, 16, 1, |
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data, pool->size, 1); |
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break; |
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} |
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} |
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if (!(mem_flags & __GFP_ZERO)) |
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memset(retval, POOL_POISON_ALLOCATED, pool->size); |
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#endif |
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spin_unlock_irqrestore(&pool->lock, flags); |
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if (want_init_on_alloc(mem_flags)) |
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memset(retval, 0, pool->size); |
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return retval; |
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} |
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EXPORT_SYMBOL(dma_pool_alloc); |
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static struct dma_page *pool_find_page(struct dma_pool *pool, dma_addr_t dma) |
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{ |
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struct dma_page *page; |
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list_for_each_entry(page, &pool->page_list, page_list) { |
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if (dma < page->dma) |
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continue; |
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if ((dma - page->dma) < pool->allocation) |
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return page; |
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} |
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return NULL; |
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} |
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/** |
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* dma_pool_free - put block back into dma pool |
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* @pool: the dma pool holding the block |
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* @vaddr: virtual address of block |
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* @dma: dma address of block |
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* |
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* Caller promises neither device nor driver will again touch this block |
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* unless it is first re-allocated. |
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*/ |
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void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma) |
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{ |
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struct dma_page *page; |
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unsigned long flags; |
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unsigned int offset; |
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spin_lock_irqsave(&pool->lock, flags); |
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page = pool_find_page(pool, dma); |
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if (!page) { |
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spin_unlock_irqrestore(&pool->lock, flags); |
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if (pool->dev) |
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dev_err(pool->dev, "%s %s, %p/%pad (bad dma)\n", |
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__func__, pool->name, vaddr, &dma); |
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else |
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pr_err("%s %s, %p/%pad (bad dma)\n", |
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__func__, pool->name, vaddr, &dma); |
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return; |
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} |
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offset = vaddr - page->vaddr; |
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if (want_init_on_free()) |
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memset(vaddr, 0, pool->size); |
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#ifdef DMAPOOL_DEBUG |
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if ((dma - page->dma) != offset) { |
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spin_unlock_irqrestore(&pool->lock, flags); |
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if (pool->dev) |
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dev_err(pool->dev, "%s %s, %p (bad vaddr)/%pad\n", |
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__func__, pool->name, vaddr, &dma); |
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else |
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pr_err("%s %s, %p (bad vaddr)/%pad\n", |
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__func__, pool->name, vaddr, &dma); |
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return; |
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} |
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{ |
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unsigned int chain = page->offset; |
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while (chain < pool->allocation) { |
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if (chain != offset) { |
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chain = *(int *)(page->vaddr + chain); |
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continue; |
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} |
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spin_unlock_irqrestore(&pool->lock, flags); |
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if (pool->dev) |
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dev_err(pool->dev, "%s %s, dma %pad already free\n", |
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__func__, pool->name, &dma); |
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else |
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pr_err("%s %s, dma %pad already free\n", |
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__func__, pool->name, &dma); |
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return; |
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} |
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} |
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memset(vaddr, POOL_POISON_FREED, pool->size); |
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#endif |
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page->in_use--; |
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*(int *)vaddr = page->offset; |
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page->offset = offset; |
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/* |
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* Resist a temptation to do |
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* if (!is_page_busy(page)) pool_free_page(pool, page); |
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* Better have a few empty pages hang around. |
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*/ |
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spin_unlock_irqrestore(&pool->lock, flags); |
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} |
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EXPORT_SYMBOL(dma_pool_free); |
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/* |
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* Managed DMA pool |
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*/ |
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static void dmam_pool_release(struct device *dev, void *res) |
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{ |
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struct dma_pool *pool = *(struct dma_pool **)res; |
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dma_pool_destroy(pool); |
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} |
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static int dmam_pool_match(struct device *dev, void *res, void *match_data) |
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{ |
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return *(struct dma_pool **)res == match_data; |
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} |
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/** |
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* dmam_pool_create - Managed dma_pool_create() |
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* @name: name of pool, for diagnostics |
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* @dev: device that will be doing the DMA |
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* @size: size of the blocks in this pool. |
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* @align: alignment requirement for blocks; must be a power of two |
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* @allocation: returned blocks won't cross this boundary (or zero) |
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* |
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* Managed dma_pool_create(). DMA pool created with this function is |
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* automatically destroyed on driver detach. |
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* |
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* Return: a managed dma allocation pool with the requested |
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* characteristics, or %NULL if one can't be created. |
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*/ |
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struct dma_pool *dmam_pool_create(const char *name, struct device *dev, |
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size_t size, size_t align, size_t allocation) |
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{ |
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struct dma_pool **ptr, *pool; |
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ptr = devres_alloc(dmam_pool_release, sizeof(*ptr), GFP_KERNEL); |
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if (!ptr) |
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return NULL; |
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pool = *ptr = dma_pool_create(name, dev, size, align, allocation); |
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if (pool) |
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devres_add(dev, ptr); |
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else |
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devres_free(ptr); |
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return pool; |
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} |
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EXPORT_SYMBOL(dmam_pool_create); |
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|
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/** |
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* dmam_pool_destroy - Managed dma_pool_destroy() |
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* @pool: dma pool that will be destroyed |
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* |
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* Managed dma_pool_destroy(). |
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*/ |
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void dmam_pool_destroy(struct dma_pool *pool) |
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{ |
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struct device *dev = pool->dev; |
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WARN_ON(devres_release(dev, dmam_pool_release, dmam_pool_match, pool)); |
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} |
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EXPORT_SYMBOL(dmam_pool_destroy);
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