From 92b20c40dcca2d441f367da57e7665cce15c492a Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Sat, 11 Nov 2006 17:25:14 +1100 Subject: [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 Signed-off-by: Paul Mackerras --- arch/powerpc/kernel/dma_64.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) (limited to 'arch/powerpc/kernel/dma_64.c') 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; } -- cgit v1.2.3