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Commit b18814e7 authored by Christoph Hellwig's avatar Christoph Hellwig
Browse files

dma-direct: provide page based alloc/free helpers 



Some architectures support remapping highmem into DMA coherent
allocations.  To use the common code for them we need variants of
dma_direct_{alloc,free}_pages that do not use kernel virtual addresses.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarRobin Murphy <robin.murphy@arm.com>
parent c9d76d06

include/linux/dma-direct.h

+3 −0
Original line number Diff line number Diff line
@@ -67,6 +67,9 @@ void *dma_direct_alloc_pages(struct device *dev, size_t size, 
		dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs);

void dma_direct_free_pages(struct device *dev, size_t size, void *cpu_addr,

		dma_addr_t dma_addr, unsigned long attrs);

struct page *__dma_direct_alloc_pages(struct device *dev, size_t size,

		dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs);

void __dma_direct_free_pages(struct device *dev, size_t size, struct page *page);

dma_addr_t dma_direct_map_page(struct device *dev, struct page *page,

		unsigned long offset, size_t size, enum dma_data_direction dir,

		unsigned long attrs);

kernel/dma/direct.c

+22 −10
Original line number Diff line number Diff line
@@ -103,14 +103,13 @@ static bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size) 
			min_not_zero(dev->coherent_dma_mask, dev->bus_dma_mask);

}



void *dma_direct_alloc_pages(struct device *dev, size_t size,

struct page *__dma_direct_alloc_pages(struct device *dev, size_t size,

		dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)

{

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

	int page_order = get_order(size);

	struct page *page = NULL;

	u64 phys_mask;

	void *ret;



	if (attrs & DMA_ATTR_NO_WARN)

		gfp |= __GFP_NOWARN;
@@ -150,11 +149,22 @@ void *dma_direct_alloc_pages(struct device *dev, size_t size, 
		}

	}



	return page;

}



void *dma_direct_alloc_pages(struct device *dev, size_t size,

		dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)

{

	struct page *page;

	void *ret;



	page = __dma_direct_alloc_pages(dev, size, dma_handle, gfp, attrs);

	if (!page)

		return NULL;



	ret = page_address(page);

	if (force_dma_unencrypted()) {

		set_memory_decrypted((unsigned long)ret, 1 << page_order);

		set_memory_decrypted((unsigned long)ret, 1 << get_order(size));

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

	} else {

		*dma_handle = phys_to_dma(dev, page_to_phys(page));
@@ -163,20 +173,22 @@ void *dma_direct_alloc_pages(struct device *dev, size_t size, 
	return ret;

}



/*

 * NOTE: this function must never look at the dma_addr argument, because we want

 * to be able to use it as a helper for iommu implementations as well.

 */

void __dma_direct_free_pages(struct device *dev, size_t size, struct page *page)

{

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



	if (!dma_release_from_contiguous(dev, page, count))

		__free_pages(page, get_order(size));

}



void dma_direct_free_pages(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;

	unsigned int page_order = get_order(size);



	if (force_dma_unencrypted())

		set_memory_encrypted((unsigned long)cpu_addr, 1 << page_order);

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

		free_pages((unsigned long)cpu_addr, page_order);

	__dma_direct_free_pages(dev, size, virt_to_page(cpu_addr));

}



void *dma_direct_alloc(struct device *dev, size_t size,