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| author | Vladimir Murzin <vladimir.murzin@arm.com> | 2017-06-26 10:18:55 +0100 |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2017-06-28 06:55:01 -0700 |
| commit | 25f1e18870881f3366a5abec27b651983ce9032c (patch) | |
| tree | dd890a4805e5505ad46dd430c023a9dc5606f215 /lib | |
| parent | 63d36c95500400642f656ba1970980746cf437f3 (diff) | |
| download | lwn-25f1e18870881f3366a5abec27b651983ce9032c.tar.gz lwn-25f1e18870881f3366a5abec27b651983ce9032c.zip | |
dma: Take into account dma_pfn_offset
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>
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/dma-noop.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/lib/dma-noop.c b/lib/dma-noop.c index 643a074f139d..acc4190e2731 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; } |