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Commit 080321d3 authored by Christoph Hellwig's avatar Christoph Hellwig
Browse files

dma-direct: add support for CMA allocation 



Try the CMA allocator for coherent allocations if supported.

Roughly modelled after the x86 code.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent 27975969

lib/dma-direct.c

+18 −6
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 
#include <linux/mm.h>

#include <linux/dma-direct.h>

#include <linux/scatterlist.h>

#include <linux/dma-contiguous.h>

#include <linux/pfn.h>



#define DIRECT_MAPPING_ERROR		0
@@ -29,18 +30,29 @@ check_addr(struct device *dev, dma_addr_t dma_addr, size_t size, 
static void *dma_direct_alloc(struct device *dev, size_t size,

		dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)

{

	void *ret;

	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;

	int page_order = get_order(size);

	struct page *page = NULL;



	ret = (void *)__get_free_pages(gfp, get_order(size));

	if (ret)

		*dma_handle = phys_to_dma(dev, virt_to_phys(ret));

	/* CMA can be used only in the context which permits sleeping */

	if (gfpflags_allow_blocking(gfp))

		page = dma_alloc_from_contiguous(dev, count, page_order, gfp);

	if (!page)

		page = alloc_pages(gfp, page_order);

	if (!page)

		return NULL;



	return ret;

	*dma_handle = phys_to_dma(dev, page_to_phys(page));

	memset(page_address(page), 0, size);

	return page_address(page);

}



static void dma_direct_free(struct device *dev, size_t size, void *cpu_addr,

		dma_addr_t dma_addr, unsigned long attrs)

{

	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;



	if (!dma_release_from_contiguous(dev, virt_to_page(cpu_addr), count))

		free_pages((unsigned long)cpu_addr, get_order(size));

}