diff options
| -rw-r--r-- | arch/x86/kernel/pci-dma_32.c | 34 |
1 files changed, 29 insertions, 5 deletions
diff --git a/arch/x86/kernel/pci-dma_32.c b/arch/x86/kernel/pci-dma_32.c index debe9119b72..11f100a5f03 100644 --- a/arch/x86/kernel/pci-dma_32.c +++ b/arch/x86/kernel/pci-dma_32.c @@ -76,6 +76,8 @@ void *dma_alloc_coherent(struct device *dev, size_t size, struct page *page; dma_addr_t bus; int order = get_order(size); + unsigned long dma_mask = 0; + /* ignore region specifiers */ gfp &= ~(__GFP_DMA | __GFP_HIGHMEM); @@ -85,15 +87,37 @@ void *dma_alloc_coherent(struct device *dev, size_t size, if (!dev) dev = &fallback_dev; + dma_mask = dev->coherent_dma_mask; + if (dma_mask == 0) + dma_mask = DMA_32BIT_MASK; + + again: page = dma_alloc_pages(dev, gfp, order); if (page == NULL) return NULL; - ret = page_address(page); - bus = page_to_phys(page); - - memset(ret, 0, size); - *dma_handle = bus; + { + int high, mmu; + bus = page_to_phys(page); + ret = page_address(page); + high = (bus + size) >= dma_mask; + mmu = high; + if (force_iommu && !(gfp & GFP_DMA)) + mmu = 1; + else if (high) { + free_pages((unsigned long)ret, + get_order(size)); + + /* Don't use the 16MB ZONE_DMA unless absolutely + needed. It's better to use remapping first. */ + if (dma_mask < DMA_32BIT_MASK && !(gfp & GFP_DMA)) { + gfp = (gfp & ~GFP_DMA32) | GFP_DMA; + goto again; + } + } + memset(ret, 0, size); + *dma_handle = bus; + } return ret; } |