419 lines
11 KiB
C
419 lines
11 KiB
C
/*
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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 <willy@linux.intel.com>
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*
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* This software may be redistributed and/or modified under the terms of
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* the GNU General Public License ("GPL") version 2 as published by the
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* Free Software Foundation.
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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/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/slab.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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#include <linux/mutex.h>
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#include <syscall.h>
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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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/**
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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: !in_interrupt()
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*
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* Returns a dma allocation pool with the requested characteristics, or
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* null if one can't be created. 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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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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if ((size % align) != 0)
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size = ALIGN(size, align);
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allocation = max_t(size_t, size, PAGE_SIZE);
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allocation = (allocation+0x7FFF) & ~0x7FFF;
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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(sizeof(*retval), GFP_KERNEL);
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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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return retval;
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}
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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 = (void*)KernelAlloc(pool->allocation);
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dbgprintf("%s 0x%0x ",__FUNCTION__, page->vaddr);
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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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page->dma = GetPgAddr(page->vaddr);
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dbgprintf("dma 0x%0x\n", page->dma);
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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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KernelFree(page->vaddr);
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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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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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mutex_unlock(&pools_lock);
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mutex_unlock(&pools_reg_lock);
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while (!list_empty(&pool->page_list)) {
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struct dma_page *page;
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page = list_entry(pool->page_list.next,
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struct dma_page, page_list);
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if (is_page_busy(page)) {
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printk(KERN_ERR "dma_pool_destroy %p busy\n",
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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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* This returns 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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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,
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"dma_pool_alloc %s, %p (corrupted)\n",
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pool->name, retval);
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else
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pr_err("dma_pool_alloc %s, %p (corrupted)\n",
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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 (mem_flags & __GFP_ZERO)
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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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printk(KERN_ERR "dma_pool_free %s, %p/%lx (bad dma)\n",
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pool->name, vaddr, (unsigned long)dma);
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return;
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}
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offset = vaddr - page->vaddr;
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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,
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"dma_pool_free %s, %p (bad vaddr)/%Lx\n",
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pool->name, vaddr, (unsigned long long)dma);
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else
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printk(KERN_ERR
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"dma_pool_free %s, %p (bad vaddr)/%Lx\n",
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pool->name, vaddr, (unsigned long long)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, "dma_pool_free %s, dma %Lx "
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"already free\n", pool->name,
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(unsigned long long)dma);
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else
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printk(KERN_ERR "dma_pool_free %s, dma %Lx "
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"already free\n", pool->name,
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(unsigned long long)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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