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Message-ID: <20170104180556.GP18193@arm.com>
Date: Wed, 4 Jan 2017 18:05:57 +0000
From: Will Deacon <will.deacon@....com>
To: Sricharan R <sricharan@...eaurora.org>
Cc: jcrouse@...eaurora.org, pdaly@...eaurora.org,
jgebben@...eaurora.org, joro@...tes.org,
linux-kernel@...r.kernel.org, pratikp@...eaurora.org,
iommu@...ts.linux-foundation.org, robin.murphy@....com,
tzeng@...eaurora.org, linux-arm-kernel@...ts.infradead.org,
mitchelh@...eaurora.org, vinod.koul@...el.com,
dan.j.williams@...el.com, linux@...linux.org.uk
Subject: Re: [PATCH V8 6/9] arm/dma-mapping: Implement DMA_ATTR_PRIVILEGED
On Mon, Jan 02, 2017 at 06:42:41PM +0530, Sricharan R wrote:
> The newly added DMA_ATTR_PRIVILEGED is useful for creating mappings that
> are only accessible to privileged DMA engines. Adding it to the
> arm dma-mapping.c so that the ARM32 DMA IOMMU mapper can make use of it.
>
> Signed-off-by: Sricharan R <sricharan@...eaurora.org>
> ---
> arch/arm/mm/dma-mapping.c | 60 +++++++++++++++++++++++------------------------
> 1 file changed, 30 insertions(+), 30 deletions(-)
Reviewed-by: Will Deacon <will.deacon@....com>
Russell: do you mind if I take this via the ARM SMMU tree (which goes
through Joerg's IOMMU tree)?
Will
> diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
> index ab77100..82d3e79 100644
> --- a/arch/arm/mm/dma-mapping.c
> +++ b/arch/arm/mm/dma-mapping.c
> @@ -1171,6 +1171,25 @@ static int __init dma_debug_do_init(void)
>
> #ifdef CONFIG_ARM_DMA_USE_IOMMU
>
> +static int __dma_info_to_prot(enum dma_data_direction dir, unsigned long attrs)
> +{
> + int prot = 0;
> +
> + if (attrs & DMA_ATTR_PRIVILEGED)
> + prot |= IOMMU_PRIV;
> +
> + switch (dir) {
> + case DMA_BIDIRECTIONAL:
> + return prot | IOMMU_READ | IOMMU_WRITE;
> + case DMA_TO_DEVICE:
> + return prot | IOMMU_READ;
> + case DMA_FROM_DEVICE:
> + return prot | IOMMU_WRITE;
> + default:
> + return prot;
> + }
> +}
> +
> /* IOMMU */
>
> static int extend_iommu_mapping(struct dma_iommu_mapping *mapping);
> @@ -1394,7 +1413,8 @@ static int __iommu_free_buffer(struct device *dev, struct page **pages,
> * Create a mapping in device IO address space for specified pages
> */
> static dma_addr_t
> -__iommu_create_mapping(struct device *dev, struct page **pages, size_t size)
> +__iommu_create_mapping(struct device *dev, struct page **pages, size_t size,
> + unsigned long attrs)
> {
> struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
> unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
> @@ -1419,7 +1439,7 @@ static int __iommu_free_buffer(struct device *dev, struct page **pages,
>
> len = (j - i) << PAGE_SHIFT;
> ret = iommu_map(mapping->domain, iova, phys, len,
> - IOMMU_READ|IOMMU_WRITE);
> + __dma_info_to_prot(DMA_BIDIRECTIONAL, attrs));
> if (ret < 0)
> goto fail;
> iova += len;
> @@ -1476,7 +1496,8 @@ static struct page **__iommu_get_pages(void *cpu_addr, unsigned long attrs)
> }
>
> static void *__iommu_alloc_simple(struct device *dev, size_t size, gfp_t gfp,
> - dma_addr_t *handle, int coherent_flag)
> + dma_addr_t *handle, int coherent_flag,
> + unsigned long attrs)
> {
> struct page *page;
> void *addr;
> @@ -1488,7 +1509,7 @@ static void *__iommu_alloc_simple(struct device *dev, size_t size, gfp_t gfp,
> if (!addr)
> return NULL;
>
> - *handle = __iommu_create_mapping(dev, &page, size);
> + *handle = __iommu_create_mapping(dev, &page, size, attrs);
> if (*handle == DMA_ERROR_CODE)
> goto err_mapping;
>
> @@ -1522,7 +1543,7 @@ static void *__arm_iommu_alloc_attrs(struct device *dev, size_t size,
>
> if (coherent_flag == COHERENT || !gfpflags_allow_blocking(gfp))
> return __iommu_alloc_simple(dev, size, gfp, handle,
> - coherent_flag);
> + coherent_flag, attrs);
>
> /*
> * Following is a work-around (a.k.a. hack) to prevent pages
> @@ -1537,7 +1558,7 @@ static void *__arm_iommu_alloc_attrs(struct device *dev, size_t size,
> if (!pages)
> return NULL;
>
> - *handle = __iommu_create_mapping(dev, pages, size);
> + *handle = __iommu_create_mapping(dev, pages, size, attrs);
> if (*handle == DMA_ERROR_CODE)
> goto err_buffer;
>
> @@ -1672,27 +1693,6 @@ static int arm_iommu_get_sgtable(struct device *dev, struct sg_table *sgt,
> GFP_KERNEL);
> }
>
> -static int __dma_direction_to_prot(enum dma_data_direction dir)
> -{
> - int prot;
> -
> - switch (dir) {
> - case DMA_BIDIRECTIONAL:
> - prot = IOMMU_READ | IOMMU_WRITE;
> - break;
> - case DMA_TO_DEVICE:
> - prot = IOMMU_READ;
> - break;
> - case DMA_FROM_DEVICE:
> - prot = IOMMU_WRITE;
> - break;
> - default:
> - prot = 0;
> - }
> -
> - return prot;
> -}
> -
> /*
> * Map a part of the scatter-gather list into contiguous io address space
> */
> @@ -1722,7 +1722,7 @@ static int __map_sg_chunk(struct device *dev, struct scatterlist *sg,
> if (!is_coherent && (attrs & DMA_ATTR_SKIP_CPU_SYNC) == 0)
> __dma_page_cpu_to_dev(sg_page(s), s->offset, s->length, dir);
>
> - prot = __dma_direction_to_prot(dir);
> + prot = __dma_info_to_prot(dir, attrs);
>
> ret = iommu_map(mapping->domain, iova, phys, len, prot);
> if (ret < 0)
> @@ -1930,7 +1930,7 @@ static dma_addr_t arm_coherent_iommu_map_page(struct device *dev, struct page *p
> if (dma_addr == DMA_ERROR_CODE)
> return dma_addr;
>
> - prot = __dma_direction_to_prot(dir);
> + prot = __dma_info_to_prot(dir, attrs);
>
> ret = iommu_map(mapping->domain, dma_addr, page_to_phys(page), len, prot);
> if (ret < 0)
> @@ -2036,7 +2036,7 @@ static dma_addr_t arm_iommu_map_resource(struct device *dev,
> if (dma_addr == DMA_ERROR_CODE)
> return dma_addr;
>
> - prot = __dma_direction_to_prot(dir) | IOMMU_MMIO;
> + prot = __dma_info_to_prot(dir, attrs) | IOMMU_MMIO;
>
> ret = iommu_map(mapping->domain, dma_addr, addr, len, prot);
> if (ret < 0)
> --
> QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation
>
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