Messages in this thread Patch in this message | | | From | Vladimir Murzin <> | Subject | [PATCH v5 1/7] dma: Take into account dma_pfn_offset | Date | Wed, 24 May 2017 11:24:26 +0100 |
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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> --- lib/dma-noop.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/lib/dma-noop.c b/lib/dma-noop.c index de26c8b..ff4ef5e 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, @@ -47,7 +49,7 @@ static int dma_noop_map_sg(struct device *dev, struct scatterlist *sgl, int nent 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) - PFN_PHYS(dev->dma_pfn_offset)); sg_dma_len(sg) = sg->length; } -- 2.0.0
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