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/*
* Dynamic DMA mapping support.
*
* On i386 there is no hardware dynamic DMA address translation,
* so consistent alloc/free are merely page allocation/freeing.
* The rest of the dynamic DMA mapping interface is implemented
* in asm/pci.h.
*/
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/pci.h>
#include <linux/module.h>
#include <asm/io.h>
/* For i386, we make it point to the NULL address */
dma_addr_t bad_dma_address __read_mostly = 0x0;
EXPORT_SYMBOL(bad_dma_address);
static int dma_alloc_from_coherent_mem(struct device *dev, ssize_t size,
dma_addr_t *dma_handle, void **ret)
{
struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
int order = get_order(size);
if (mem) {
int page = bitmap_find_free_region(mem->bitmap, mem->size,
order);
if (page >= 0) {
*dma_handle = mem->device_base + (page << PAGE_SHIFT);
*ret = mem->virt_base + (page << PAGE_SHIFT);
memset(*ret, 0, size);
}
if (mem->flags & DMA_MEMORY_EXCLUSIVE)
*ret = NULL;
}
return (mem != NULL);
}
static int dma_release_coherent(struct device *dev, int order, void *vaddr)
{
struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
if (mem && vaddr >= mem->virt_base && vaddr <
(mem->virt_base + (mem->size << PAGE_SHIFT))) {
int page = (vaddr - mem->virt_base) >> PAGE_SHIFT;
bitmap_release_region(mem->bitmap, page, order);
return 1;
}
return 0;
}
void *dma_alloc_coherent(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t gfp)
{
void *ret = NULL;
int order = get_order(size);
/* ignore region specifiers */
gfp &= ~(__GFP_DMA | __GFP_HIGHMEM);
if (dma_alloc_from_coherent_mem(dev, size, dma_handle, &ret))
return ret;
if (dev == NULL || (dev->coherent_dma_mask < 0xffffffff))
gfp |= GFP_DMA;
ret = (void *)__get_free_pages(gfp, order);
if (ret != NULL) {
memset(ret, 0, size);
*dma_handle = virt_to_phys(ret);
}
return ret;
}
EXPORT_SYMBOL(dma_alloc_coherent);
void dma_free_coherent(struct device *dev, size_t size,
void *vaddr, dma_addr_t dma_handle)
{
int order = get_order(size);
WARN_ON(irqs_disabled()); /* for portability */
if (dma_release_coherent(dev, order, vaddr))
return;
free_pages((unsigned long)vaddr, order);
}
EXPORT_SYMBOL(dma_free_coherent);
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