diff options
| -rw-r--r-- | Documentation/DMA-attributes.txt | 9 | ||||
| -rw-r--r-- | arch/arm64/mm/dma-mapping.c | 4 |
2 files changed, 10 insertions, 3 deletions
diff --git a/Documentation/DMA-attributes.txt b/Documentation/DMA-attributes.txt index 6eadd564a247..2ad68dbbaaae 100644 --- a/Documentation/DMA-attributes.txt +++ b/Documentation/DMA-attributes.txt @@ -132,6 +132,11 @@ DMA_ATTR_FORCE_COHERENT When passed to a DMA map call the DMA_ATTR_FORCE_COHERENT DMA attribute can be used to force a buffer to be mapped as IO coherent. + +When the DMA_ATTR_FORCE_COHERENT attribute is set during a map call ensure +that it is also set during for the matching unmap call to ensure that the +correct cache maintenance is carried out. + This DMA attribute is only currently supported for arm64 stage 1 IOMMU mappings. @@ -143,5 +148,9 @@ coherent. The DMA_ATTR_FORCE_NON_COHERENT DMA attribute overrides the buffer IO coherency configuration set by making the device IO coherent. +When the DMA_ATTR_FORCE_NON_COHERENT attribute is set during a map call +ensure that it is also set during for the matching unmap call to ensure +that the correct cache maintenance is carried out. + This DMA attribute is only currently supported for arm64 stage 1 IOMMU mappings. diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c index 45c365290553..2445db9bbd4f 100644 --- a/arch/arm64/mm/dma-mapping.c +++ b/arch/arm64/mm/dma-mapping.c @@ -1821,10 +1821,8 @@ static void arm_iommu_unmap_page(struct device *dev, dma_addr_t handle, mapping->domain, iova)); int offset = handle & ~PAGE_MASK; int len = PAGE_ALIGN(size + offset); - bool iova_coherent = iommu_is_iova_coherent(mapping->domain, - handle); - if (!(iova_coherent || + if (!(is_dma_coherent(dev, attrs) || dma_get_attr(DMA_ATTR_SKIP_CPU_SYNC, attrs))) __dma_page_dev_to_cpu(page, offset, size, dir); |