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Commit 19e308d6 authored by Laura Abbott's avatar Laura Abbott Committed by Gerrit - the friendly Code Review server
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ARM: dma-mapping: Allow highmem pages to not have a mapping 



The DMA_ATTR_NO_KERNEL_MAPPING is used to make sure that CMA
pages have no kernel mapping. Add support to make sure that
highmem pages have no mapping.

Change-Id: Ife76df126ecfedf0dba81a35e0de8a1787355b3d
Signed-off-by: default avatarLaura Abbott <lauraa@codeaurora.org>
Signed-off-by: default avatarRohit Vaswani <rvaswani@codeaurora.org>
Signed-off-by: default avatarVijayanand Jitta <vjitta@codeaurora.org>
Signed-off-by: default avatarCharan Teja Reddy <charante@codeaurora.org>
parent 05d90a59

arch/arm/mm/dma-mapping.c

+23 −11
Original line number Diff line number Diff line
@@ -116,7 +116,7 @@ static void * 
__dma_alloc_remap(struct page *page, size_t size, gfp_t gfp, pgprot_t prot,

		const void *caller);



static void __dma_free_remap(void *cpu_addr, size_t size);

static void __dma_free_remap(void *cpu_addr, size_t size, bool warn);



static inline pgprot_t __get_dma_pgprot(unsigned long attrs, pgprot_t prot);
@@ -392,10 +392,10 @@ __dma_alloc_remap(struct page *page, size_t size, gfp_t gfp, pgprot_t prot, 
			prot, caller);

}



static void __dma_free_remap(void *cpu_addr, size_t size)

static void __dma_free_remap(void *cpu_addr, size_t size, bool no_warn)

{

	dma_common_free_remap(cpu_addr, size,

			VM_ARM_DMA_CONSISTENT | VM_USERMAP, false);

			VM_ARM_DMA_CONSISTENT | VM_USERMAP, no_warn);

}



#define DEFAULT_DMA_COHERENT_POOL_SIZE	SZ_256K
@@ -583,12 +583,14 @@ static void __dma_remap(struct page *page, size_t size, pgprot_t prot, 
	flush_tlb_kernel_range(start, end);

}





#define NO_KERNEL_MAPPING_DUMMY	0x2222

static void *__alloc_remap_buffer(struct device *dev, size_t size, gfp_t gfp,

				 pgprot_t prot, struct page **ret_page,

				 const void *caller, bool want_vaddr)

{

	struct page *page;

	void *ptr = NULL;

	void *ptr = (void *)NO_KERNEL_MAPPING_DUMMY;

	/*

	 * __alloc_remap_buffer is only called when the device is

	 * non-coherent
@@ -663,11 +665,21 @@ static void *__alloc_from_contiguous(struct device *dev, size_t size, 
	__dma_clear_buffer(page, size, coherent_flag);



	if (PageHighMem(page)) {

		ptr = __dma_alloc_remap(page, size, GFP_KERNEL, prot, caller);

		if (!want_vaddr) {

			/*

			 * Something non-NULL needs to be returned here. Give

			 * back a dummy address that is unmapped to catch

			 * clients trying to use the address incorrectly

			 */

			ptr = (void *)NO_KERNEL_MAPPING_DUMMY;

		} else {

			ptr = __dma_alloc_remap(page, size, GFP_KERNEL, prot,

						caller);

			if (!ptr) {

				dma_release_from_contiguous(dev, page, count);

				return NULL;

			}

		}

	} else {

		__dma_remap(page, size, prot, want_vaddr);

		ptr = page_address(page);
@@ -681,7 +693,7 @@ static void __free_from_contiguous(struct device *dev, struct page *page, 
				   void *cpu_addr, size_t size, bool want_vaddr)

{

	if (PageHighMem(page))

		__dma_free_remap(cpu_addr, size);

		__dma_free_remap(cpu_addr, size, true);

	else

		__dma_remap(page, size, PAGE_KERNEL, true);

	dma_release_from_contiguous(dev, page, size >> PAGE_SHIFT);
@@ -777,7 +789,7 @@ static void *remap_allocator_alloc(struct arm_dma_alloc_args *args, 
static void remap_allocator_free(struct arm_dma_free_args *args)

{

	if (args->want_vaddr)

		__dma_free_remap(args->cpu_addr, args->size);

		__dma_free_remap(args->cpu_addr, args->size, false);



	__dma_free_buffer(args->page, args->size);

}
@@ -864,7 +876,7 @@ static void *__dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, 
		kfree(buf);

	}



	return args.want_vaddr ? addr : page;

	return  addr;

}



/*