x86: add alloc_coherent dma_ops callback to NOMMU driver

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 55 insertions, 0 deletions

diff --git a/arch/x86/kernel/pci-nommu.c b/arch/x86/kernel/pci-nommu.c
index 3f91f71cdc3e..b8ce83c98211 100644
--- a/arch/x86/kernel/pci-nommu.c
+++ b/arch/x86/kernel/pci-nommu.c
@@ -72,7 +72,62 @@ static int nommu_map_sg(struct device *hwdev, struct scatterlist *sg,
         return nents;
 }
 
+static void *
+nommu_alloc_coherent(struct device *hwdev, size_t size,
+                     dma_addr_t *dma_addr, gfp_t gfp)
+{
+        unsigned long dma_mask;
+        int node;
+        struct page *page;
+
+        if (hwdev->dma_mask == NULL)
+                return NULL;
+
+        gfp &= ~(__GFP_DMA | __GFP_HIGHMEM | __GFP_DMA32);
+        gfp |= __GFP_ZERO;
+
+        dma_mask = hwdev->coherent_dma_mask;
+        if (!dma_mask)
+                dma_mask = *(hwdev->dma_mask);
+
+        if (dma_mask < DMA_24BIT_MASK)
+                return NULL;
+
+        node = dev_to_node(hwdev);
+
+#ifdef CONFIG_X86_64
+        if (dma_mask <= DMA_32BIT_MASK)
+                gfp |= GFP_DMA32;
+#endif
+
+        /* No alloc-free penalty for ISA devices */
+        if (dma_mask == DMA_24BIT_MASK)
+                gfp |= GFP_DMA;
+
+again:
+        page = alloc_pages_node(node, gfp, get_order(size));
+        if (!page)
+                return NULL;
+
+        if ((page_to_phys(page) + size > dma_mask) && !(gfp & GFP_DMA)) {
+                free_pages((unsigned long)page_address(page), get_order(size));
+                gfp |= GFP_DMA;
+                goto again;
+        }
+
+        *dma_addr = page_to_phys(page);
+        if (check_addr("alloc_coherent", hwdev, *dma_addr, size)) {
+                flush_write_buffers();
+                return page_address(page);
+        }
+
+        free_pages((unsigned long)page_address(page), get_order(size));
+
+        return NULL;
+}
+
 struct dma_mapping_ops nommu_dma_ops = {
+        .alloc_coherent = nommu_alloc_coherent,
         .map_single = nommu_map_single,
         .map_sg = nommu_map_sg,
         .is_phys = 1,