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authorBenjamin Herrenschmidt <benh@kernel.crashing.org>2006-11-11 17:25:14 +1100
committerPaul Mackerras <paulus@samba.org>2006-12-04 20:38:57 +1100
commit92b20c40dcca2d441f367da57e7665cce15c492a (patch)
tree937e98acbbc3db12c8ed99c4499794d39287f98f /arch
parent3bc0f40c287a435805b0545ffc44ea41f11cd43e (diff)
[POWERPC] Add an optional offset to direct DMA on 64 bits
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>
Diffstat (limited to 'arch')
-rw-r--r--arch/powerpc/kernel/dma_64.c11
1 files changed, 8 insertions, 3 deletions
diff --git a/arch/powerpc/kernel/dma_64.c b/arch/powerpc/kernel/dma_64.c
index 4e655119978..1d1dc76606a 100644
--- a/arch/powerpc/kernel/dma_64.c
+++ b/arch/powerpc/kernel/dma_64.c
@@ -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;
}