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    Subject[PATCH AUTOSEL for 4.9 162/293] dma: Take into account dma_pfn_offset
    Date
    From: Vladimir Murzin <vladimir.murzin@arm.com>

    [ Upstream commit 25f1e18870881f3366a5abec27b651983ce9032c ]

    Even though dma-noop-ops assumes 1:1 memory mapping DMA memory range
    can be different to RAM. For example, ARM STM32F4 MCU offers the
    possibility to remap SDRAM from 0xc000_0000 to 0x0 to get CPU
    performance boost, but DMA continue to see SDRAM at 0xc000_0000. This
    difference in mapping is handled via device-tree "dma-range" property
    which leads to dev->dma_pfn_offset is set nonzero. To handle such
    cases take dma_pfn_offset into account.

    Cc: Joerg Roedel <jroedel@suse.de>
    Cc: Christian Borntraeger <borntraeger@de.ibm.com>
    Reported-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
    Tested-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
    Tested-by: Andras Szemzo <sza@esh.hu>
    Tested-by: Alexandre TORGUE <alexandre.torgue@st.com>
    Reviewed-by: Robin Murphy <robin.murphy@arm.com>
    Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
    Signed-off-by: Christoph Hellwig <hch@lst.de>
    Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
    ---
    lib/dma-noop.c | 9 ++++++---
    1 file changed, 6 insertions(+), 3 deletions(-)

    diff --git a/lib/dma-noop.c b/lib/dma-noop.c
    index 3d766e78fbe2..9a7b5ed7ceac 100644
    --- a/lib/dma-noop.c
    +++ b/lib/dma-noop.c
    @@ -7,6 +7,7 @@
    #include <linux/mm.h>
    #include <linux/dma-mapping.h>
    #include <linux/scatterlist.h>
    +#include <linux/pfn.h>

    static void *dma_noop_alloc(struct device *dev, size_t size,
    dma_addr_t *dma_handle, gfp_t gfp,
    @@ -16,7 +17,8 @@ static void *dma_noop_alloc(struct device *dev, size_t size,

    ret = (void *)__get_free_pages(gfp, get_order(size));
    if (ret)
    - *dma_handle = virt_to_phys(ret);
    + *dma_handle = virt_to_phys(ret) - PFN_PHYS(dev->dma_pfn_offset);
    +
    return ret;
    }

    @@ -32,7 +34,7 @@ static dma_addr_t dma_noop_map_page(struct device *dev, struct page *page,
    enum dma_data_direction dir,
    unsigned long attrs)
    {
    - return page_to_phys(page) + offset;
    + return page_to_phys(page) + offset - PFN_PHYS(dev->dma_pfn_offset);
    }

    static int dma_noop_map_sg(struct device *dev, struct scatterlist *sgl, int nents,
    @@ -43,11 +45,12 @@ static int dma_noop_map_sg(struct device *dev, struct scatterlist *sgl, int nent
    struct scatterlist *sg;

    for_each_sg(sgl, sg, nents, i) {
    + dma_addr_t offset = PFN_PHYS(dev->dma_pfn_offset);
    void *va;

    BUG_ON(!sg_page(sg));
    va = sg_virt(sg);
    - sg_dma_address(sg) = (dma_addr_t)virt_to_phys(va);
    + sg_dma_address(sg) = (dma_addr_t)virt_to_phys(va) - offset;
    sg_dma_len(sg) = sg->length;
    }

    --
    2.15.1
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