Will Deacon <[email protected]> wrote @ Tue, 25 Jun 2013 13:37:14 +0200: ... > > Do we need similar changes for map_sg case as well? They still passes '0' > > as prot. > > Yes, we could use the same trick there (probably worth moving the logic into > a helper function for translating dma_data_direction into IOMMU_* values). > > There are also iommu_map calls when allocating DMA buffers, but I think 0 is > the right thing to pass there (i.e. no permission until pages have been > explicitly mapped). Although, to be honest, I don't see why we need to map > the buffer at all when we allocate it.
Yes, I thought too. I have a patch for that as below. If you like, I'll rebase and send for merge with the one which changes dma-mapping.c. >From 699e6bd4fef86383d197775486b47bcbdc594f4a Mon Sep 17 00:00:00 2001 From: Hiroshi Doyu <[email protected]> Date: Tue, 25 Jun 2013 13:43:29 +0300 Subject: [PATCH 1/2] iommu/core: convert DMA direction into IOMMU protection attributes Introduce a new function to convert DMA direction into IOMMU protection attributes. Signed-off-by: Hiroshi Doyu <[email protected]> --- include/linux/iommu.h | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/include/linux/iommu.h b/include/linux/iommu.h index 00af00f..ce3be78 100644 --- a/include/linux/iommu.h +++ b/include/linux/iommu.h @@ -21,11 +21,26 @@ #include <linux/errno.h> #include <linux/types.h> +#include <linux/dma-direction.h> #define IOMMU_READ (1) #define IOMMU_WRITE (2) #define IOMMU_CACHE (4) /* DMA cache coherency */ +static inline int to_iommu_prot(enum dma_data_direction dir) +{ + switch (dir) { + case DMA_BIDIRECTIONAL: + return IOMMU_READ | IOMMU_WRITE; + case DMA_TO_DEVICE: + return IOMMU_READ; + case DMA_FROM_DEVICE: + return IOMMU_WRITE; + default: + return 0; + } +} + struct iommu_ops; struct iommu_group; struct bus_type; -- 1.8.1.5 -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
