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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>
hifive-unleashed-5.1
Vladimir Murzin 2017-06-26 10:18:55 +01:00 committed by Christoph Hellwig
parent 63d36c9550
commit 25f1e18870
1 changed files with 6 additions and 3 deletions
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9
lib/dma-noop.c
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@ -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;
}