iommu: msm: add barrier call on coherent lazy map (ea236038) · Commits · e / devices / android_kernel_fairphone_FP3

When clients of the lazy APIs enable IO coherency they will skip their cache maintenance code. However before passing a coherent buffer to the device for DMA a barrier call must still be made to ensure the caches are up to date. Add this barrier call to the lazy map function when IO coherency is enabled. Change-Id: I3fc065f8aeff705283211e59bd641d81b4e74067 Signed-off-by:

Liam Mark <lmark@codeaurora.org> Signed-off-by:

Patrick Daly <pdaly@codeaurora.org>

drivers/iommu/msm_dma_iommu_mapping.c

+8 −4

Original line number	Diff line number	Diff line
		@@ -17,6 +17,7 @@
		#include <linux/rbtree.h>
		#include <linux/mutex.h>
		#include <linux/err.h>
		#include <asm/barrier.h>

		#include <linux/msm_dma_iommu_mapping.h>

		@@ -205,10 +206,13 @@ static inline int __msm_dma_map_sg(struct device dev, struct scatterlist sg,
		sg->dma_length = iommu_map->sgl.dma_length;

		kref_get(&iommu_map->ref);
		if (is_device_dma_coherent(dev))
		/*
		* Need to do cache operations here based on "dir" in the
		* future if we go with coherent mappings.
		* Ensure all outstanding changes for coherent
		* buffers are applied to the cache before any
		* DMA occurs.
		*/
		dmb(ish);
		ret = nents;
		}
		mutex_unlock(&iommu_meta->lock);