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[POWERPC] Add an optional offset to direct DMA on 64 bits

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This patch adds an optional global offset that can be added to DMA addresses
when using the direct DMA operations.

That brings it a step closer to the 32 bits direct DMA operations, and makes
it useable on Cell when the MMU is disabled and we are using a spider
southbridge.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This commit is contained in:
Benjamin Herrenschmidt 2006-11-11 17:25:14 +11:00 committed by Paul Mackerras
parent 3bc0f40c28
commit 92b20c40dc
2 changed files with 10 additions and 3 deletions
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11
arch/powerpc/kernel/dma_64.c
View file

@ -111,7 +111,11 @@ EXPORT_SYMBOL(dma_iommu_ops);
/*
* Generic direct DMA implementation
*
* This implementation supports a global offset that can be applied if
* the address at which memory is visible to devices is not 0.
*/
unsigned long dma_direct_offset;
static void *dma_direct_alloc_coherent(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t flag)
@ -122,7 +126,7 @@ static void *dma_direct_alloc_coherent(struct device *dev, size_t size,
ret = (void *)__get_free_pages(flag, get_order(size));
if (ret != NULL) {
memset(ret, 0, size);
*dma_handle = virt_to_abs(ret);
*dma_handle = virt_to_abs(ret) | dma_direct_offset;
}
return ret;
}
@ -137,7 +141,7 @@ static dma_addr_t dma_direct_map_single(struct device *dev, void *ptr,
size_t size,
enum dma_data_direction direction)
{
return virt_to_abs(ptr);
return virt_to_abs(ptr) | dma_direct_offset;
}
static void dma_direct_unmap_single(struct device *dev, dma_addr_t dma_addr,
@ -152,7 +156,8 @@ static int dma_direct_map_sg(struct device *dev, struct scatterlist *sg,
int i;
for (i = 0; i < nents; i++, sg++) {
sg->dma_address = page_to_phys(sg->page) + sg->offset;
sg->dma_address = (page_to_phys(sg->page) + sg->offset) |
dma_direct_offset;
sg->dma_length = sg->length;
}

2
include/asm-powerpc/dma-mapping.h
View file

@ -187,6 +187,8 @@ static inline void dma_unmap_sg(struct device *dev, struct scatterlist *sg,
extern struct dma_mapping_ops dma_iommu_ops;
extern struct dma_mapping_ops dma_direct_ops;
extern unsigned long dma_direct_offset;
#else /* CONFIG_PPC64 */
#define dma_supported(dev, mask) (1)