4 files changed, 42 insertions, 20 deletions

diff --git a/arch/tile/include/asm/device.h b/arch/tile/include/asm/device.h
index 5182705bd056..6ab8bf146d4c 100644
--- a/arch/tile/include/asm/device.h
+++ b/arch/tile/include/asm/device.h
@@ -23,7 +23,10 @@ struct dev_archdata {
         /* Offset of the DMA address from the PA. */
         dma_addr_t              dma_offset;
 
-        /* Highest DMA address that can be generated by this device. */
+        /*
+         * Highest DMA address that can be generated by devices that
+         * have limited DMA capability, i.e. non 64-bit capable.
+         */
         dma_addr_t              max_direct_dma_addr;
 };
 
diff --git a/arch/tile/include/asm/dma-mapping.h b/arch/tile/include/asm/dma-mapping.h
index 6f522d569132..1eae359d8315 100644
--- a/arch/tile/include/asm/dma-mapping.h
+++ b/arch/tile/include/asm/dma-mapping.h
@@ -92,14 +92,19 @@ dma_set_mask(struct device *dev, u64 mask)
 {
         struct dma_map_ops *dma_ops = get_dma_ops(dev);
 
-        /* Handle legacy PCI devices with limited memory addressability. */
-        if ((dma_ops == gx_pci_dma_map_ops ||
-             dma_ops == gx_hybrid_pci_dma_map_ops ||
-             dma_ops == gx_legacy_pci_dma_map_ops) &&
-            (mask <= DMA_BIT_MASK(32))) {
-                set_dma_ops(dev, gx_legacy_pci_dma_map_ops);
-                set_dma_offset(dev, 0);
-                if (mask > dev->archdata.max_direct_dma_addr)
+        /*
+         * For PCI devices with 64-bit DMA addressing capability, promote
+         * the dma_ops to hybrid, with the consistent memory DMA space limited
+         * to 32-bit. For 32-bit capable devices, limit the streaming DMA
+         * address range to max_direct_dma_addr.
+         */
+        if (dma_ops == gx_pci_dma_map_ops ||
+            dma_ops == gx_hybrid_pci_dma_map_ops ||
+            dma_ops == gx_legacy_pci_dma_map_ops) {
+                if (mask == DMA_BIT_MASK(64) &&
+                    dma_ops == gx_legacy_pci_dma_map_ops)
+                        set_dma_ops(dev, gx_hybrid_pci_dma_map_ops);
+                else if (mask > dev->archdata.max_direct_dma_addr)
                         mask = dev->archdata.max_direct_dma_addr;
         }
 
diff --git a/arch/tile/kernel/pci-dma.c b/arch/tile/kernel/pci-dma.c
index d94f4872e94f..09b58703ac26 100644
--- a/arch/tile/kernel/pci-dma.c
+++ b/arch/tile/kernel/pci-dma.c
@@ -588,15 +588,18 @@ int dma_set_coherent_mask(struct device *dev, u64 mask)
 {
         struct dma_map_ops *dma_ops = get_dma_ops(dev);
 
-        /* Handle hybrid PCI devices with limited memory addressability. */
-        if ((dma_ops == gx_pci_dma_map_ops ||
-             dma_ops == gx_hybrid_pci_dma_map_ops ||
-             dma_ops == gx_legacy_pci_dma_map_ops) &&
-            (mask <= DMA_BIT_MASK(32))) {
-                if (dma_ops == gx_pci_dma_map_ops)
-                        set_dma_ops(dev, gx_hybrid_pci_dma_map_ops);
-
-                if (mask > dev->archdata.max_direct_dma_addr)
+        /*
+         * For PCI devices with 64-bit DMA addressing capability, promote
+         * the dma_ops to full capability for both streams and consistent
+         * memory access. For 32-bit capable devices, limit the consistent 
+         * memory DMA range to max_direct_dma_addr.
+         */
+        if (dma_ops == gx_pci_dma_map_ops ||
+            dma_ops == gx_hybrid_pci_dma_map_ops ||
+            dma_ops == gx_legacy_pci_dma_map_ops) {
+                if (mask == DMA_BIT_MASK(64))
+                        set_dma_ops(dev, gx_pci_dma_map_ops);
+                else if (mask > dev->archdata.max_direct_dma_addr)
                         mask = dev->archdata.max_direct_dma_addr;
         }
 
diff --git a/arch/tile/kernel/pci_gx.c b/arch/tile/kernel/pci_gx.c
index 66ef9db5c2fb..29acac6af4ba 100644
--- a/arch/tile/kernel/pci_gx.c
+++ b/arch/tile/kernel/pci_gx.c
@@ -1081,13 +1081,24 @@ int pcibios_enable_device(struct pci_dev *dev, int mask)
         return pci_enable_resources(dev, mask);
 }
 
-/* Called for each device after PCI setup is done. */
+/*
+ * Called for each device after PCI setup is done.
+ * We initialize the PCI device capabilities conservatively, assuming that
+ * all devices can only address the 32-bit DMA space. The exception here is
+ * that the device dma_offset is set to the value that matches the 64-bit
+ * capable devices. This is OK because dma_offset is not used by legacy
+ * dma_ops, nor by the hybrid dma_ops's streaming DMAs, which are 64-bit ops.
+ * This implementation matches the kernel design of setting PCI devices'
+ * coherent_dma_mask to 0xffffffffull by default, allowing the device drivers
+ * to skip calling pci_set_consistent_dma_mask(DMA_BIT_MASK(32)).
+ */
 static void pcibios_fixup_final(struct pci_dev *pdev)
 {
-        set_dma_ops(&pdev->dev, gx_pci_dma_map_ops);
+        set_dma_ops(&pdev->dev, gx_legacy_pci_dma_map_ops);
         set_dma_offset(&pdev->dev, TILE_PCI_MEM_MAP_BASE_OFFSET);
         pdev->dev.archdata.max_direct_dma_addr =
                 TILE_PCI_MAX_DIRECT_DMA_ADDRESS;
+        pdev->dev.coherent_dma_mask = TILE_PCI_MAX_DIRECT_DMA_ADDRESS;
 }
 DECLARE_PCI_FIXUP_FINAL(PCI_ANY_ID, PCI_ANY_ID, pcibios_fixup_final);