drivers: dma-coherent: use MEMREMAP_WC for DMA_MEMORY_MAP (6b03ae0d) · Commits · 戴 / test

When the DMA_MEMORY_MAP flag is used, memory which can be accessed directly should be returned, so use memremap(..., MEMREMAP_WC) to provide a writecombine mapping. Signed-off-by:

Brian Starkey <brian.starkey@arm.com> Reviewed-by:

Catalin Marinas <catalin.marinas@arm.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

drivers/base/dma-coherent.c

+16 −4

Original line number	Diff line number	Diff line
		@@ -2,6 +2,7 @@
		* Coherent per-device memory handling.
		* Borrowed from i386
		*/
		#include <linux/io.h>
		#include <linux/slab.h>
		#include <linux/kernel.h>
		#include <linux/module.h>
		@@ -31,6 +32,9 @@ static bool dma_init_coherent_memory(
		if (!size)
		goto out;

		if (flags & DMA_MEMORY_MAP)
		mem_base = memremap(phys_addr, size, MEMREMAP_WC);
		else
		mem_base = ioremap(phys_addr, size);
		if (!mem_base)
		goto out;
		@@ -54,8 +58,12 @@ static bool dma_init_coherent_memory(

		out:
		kfree(dma_mem);
		if (mem_base)
		if (mem_base) {
		if (flags & DMA_MEMORY_MAP)
		memunmap(mem_base);
		else
		iounmap(mem_base);
		}
		return false;
		}

		@@ -63,6 +71,10 @@ static void dma_release_coherent_memory(struct dma_coherent_mem *mem)
		{
		if (!mem)
		return;

		if (mem->flags & DMA_MEMORY_MAP)
		memunmap(mem->virt_base);
		else
		iounmap(mem->virt_base);
		kfree(mem->bitmap);
		kfree(mem);

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