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/*
* Copyright (C) 2004-2006 Atmel Corporation
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/dma-mapping.h>
#include <linux/gfp.h>
#include <linux/export.h>
#include <asm/addrspace.h>
#include <asm/cacheflush.h>
void dma_cache_sync(struct device *dev, void *vaddr, size_t size, int direction)
{
/*
* No need to sync an uncached area
*/
if (PXSEG(vaddr) == P2SEG)
return;
switch (direction) {
case DMA_FROM_DEVICE: /* invalidate only */
invalidate_dcache_region(vaddr, size);
break;
case DMA_TO_DEVICE: /* writeback only */
clean_dcache_region(vaddr, size);
break;
case DMA_BIDIRECTIONAL: /* writeback and invalidate */
flush_dcache_region(vaddr, size);
break;
default:
BUG();
}
}
EXPORT_SYMBOL(dma_cache_sync);
static struct page *__dma_alloc(struct device *dev, size_t size,
dma_addr_t *handle, gfp_t gfp)
{
struct page *page, *free, *end;
int order;
/* Following is a work-around (a.k.a. hack) to prevent pages
* with __GFP_COMP being passed to split_page() which cannot
* handle them. The real problem is that this flag probably
* should be 0 on AVR32 as it is not supported on this
* platform--see CONFIG_HUGETLB_PAGE. */
gfp &= ~(__GFP_COMP);
size = PAGE_ALIGN(size);
order = get_order(size);
page = alloc_pages(gfp, order);
if (!page)
return NULL;
split_page(page, order);
/*
* When accessing physical memory with valid cache data, we
* get a cache hit even if the virtual memory region is marked
* as uncached.
*
* Since the memory is newly allocated, there is no point in
* doing a writeback. If the previous owner cares, he should
* have flushed the cache before releasing the memory.
*/
invalidate_dcache_region(phys_to_virt(page_to_phys(page)), size);
*handle = page_to_bus(page);
free = page + (size >> PAGE_SHIFT);
end = page + (1 << order);
/*
* Free any unused pages
*/
while (free < end) {
__free_page(free);
free++;
}
return page;
}
static void __dma_free(struct device *dev, size_t size,
struct page *page, dma_addr_t handle)
{
struct page *end = page + (PAGE_ALIGN(size) >> PAGE_SHIFT);
while (page < end)
__free_page(page++);
}
void *dma_alloc_coherent(struct device *dev, size_t size,
dma_addr_t *handle, gfp_t gfp)
{
struct page *page;
void *ret = NULL;
page = __dma_alloc(dev, size, handle, gfp);
if (page)
ret = phys_to_uncached(page_to_phys(page));
return ret;
}
EXPORT_SYMBOL(dma_alloc_coherent);
void dma_free_coherent(struct device *dev, size_t size,
void *cpu_addr, dma_addr_t handle)
{
void *addr = phys_to_cached(uncached_to_phys(cpu_addr));
struct page *page;
pr_debug("dma_free_coherent addr %p (phys %08lx) size %u\n",
cpu_addr, (unsigned long)handle, (unsigned)size);
BUG_ON(!virt_addr_valid(addr));
page = virt_to_page(addr);
__dma_free(dev, size, page, handle);
}
EXPORT_SYMBOL(dma_free_coherent);
void *dma_alloc_writecombine(struct device *dev, size_t size,
dma_addr_t *handle, gfp_t gfp)
{
struct page *page;
dma_addr_t phys;
page = __dma_alloc(dev, size, handle, gfp);
if (!page)
return NULL;
phys = page_to_phys(page);
*handle = phys;
/* Now, map the page into P3 with write-combining turned on */
return __ioremap(phys, size, _PAGE_BUFFER);
}
EXPORT_SYMBOL(dma_alloc_writecombine);
void dma_free_writecombine(struct device *dev, size_t size,
void *cpu_addr, dma_addr_t handle)
{
struct page *page;
iounmap(cpu_addr);
page = phys_to_page(handle);
__dma_free(dev, size, page, handle);
}
EXPORT_SYMBOL(dma_free_writecombine);
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