From 25f1e18870881f3366a5abec27b651983ce9032c Mon Sep 17 00:00:00 2001 From: Vladimir Murzin Date: Mon, 26 Jun 2017 10:18:55 +0100 Subject: 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 Cc: Christian Borntraeger Reported-by: Benjamin Gaignard Tested-by: Benjamin Gaignard Tested-by: Andras Szemzo Tested-by: Alexandre TORGUE Reviewed-by: Robin Murphy Signed-off-by: Vladimir Murzin Signed-off-by: Christoph Hellwig --- lib/dma-noop.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) (limited to 'lib') 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 #include #include +#include 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; } -- cgit