From: Robin Murphy <robin.murphy@xxxxxxx> On some platforms, MMIO regions might need slightly different treatment compared to mapping regular memory; add the notion of MMIO mappings to the IOMMU API's memory type flags, so that callers can let the IOMMU drivers know to do the right thing. Signed-off-by: Robin Murphy <robin.murphy@xxxxxxx> Acked-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> --- drivers/iommu/io-pgtable-arm.c | 4 +++- include/linux/iommu.h | 1 + 2 files changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c index 381ca5a..3ff4f87 100644 --- a/drivers/iommu/io-pgtable-arm.c +++ b/drivers/iommu/io-pgtable-arm.c @@ -364,7 +364,9 @@ static arm_lpae_iopte arm_lpae_prot_to_pte(struct arm_lpae_io_pgtable *data, pte |= ARM_LPAE_PTE_HAP_READ; if (prot & IOMMU_WRITE) pte |= ARM_LPAE_PTE_HAP_WRITE; - if (prot & IOMMU_CACHE) + if (prot & IOMMU_MMIO) + pte |= ARM_LPAE_PTE_MEMATTR_DEV; + else if (prot & IOMMU_CACHE) pte |= ARM_LPAE_PTE_MEMATTR_OIWB; else pte |= ARM_LPAE_PTE_MEMATTR_NC; diff --git a/include/linux/iommu.h b/include/linux/iommu.h index a5c539f..34b6432 100644 --- a/include/linux/iommu.h +++ b/include/linux/iommu.h @@ -30,6 +30,7 @@ #define IOMMU_WRITE (1 << 1) #define IOMMU_CACHE (1 << 2) /* DMA cache coherency */ #define IOMMU_NOEXEC (1 << 3) +#define IOMMU_MMIO (1 << 4) /* e.g. things like MSI doorbells */ struct iommu_ops; struct iommu_group; -- 2.7.1
