sh/PCI: Pass GAPSPCI_DMA_BASE CPU & bus address to dma_declare_coherent_memory()

dma_declare_coherent_memory() needs both the CPU physical address and the
bus address of the device memory.  They are the same on this platform, but
in general we should use pcibios_resource_to_bus() to account for any
address translation done by the PCI host bridge.

This makes no difference on Dreamcast, but is safer if the usage is copied
to future drivers.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
CC: Magnus Damm <damm@opensource.se>
CC: linux-sh@vger.kernel.org

1 files changed, 15 insertions, 3 deletions

diff --git a/arch/sh/drivers/pci/fixups-dreamcast.c b/arch/sh/drivers/pci/fixups-dreamcast.c
index d6cde700e316..1d1c5a227e50 100644
--- a/arch/sh/drivers/pci/fixups-dreamcast.c
+++ b/arch/sh/drivers/pci/fixups-dreamcast.c
@@ -31,6 +31,8 @@
 static void gapspci_fixup_resources(struct pci_dev *dev)
 {
         struct pci_channel *p = dev->sysdata;
+        struct resource res;
+        struct pci_bus_region region;
 
         printk(KERN_NOTICE "PCI: Fixing up device %s\n", pci_name(dev));
 
@@ -50,11 +52,21 @@ static void gapspci_fixup_resources(struct pci_dev *dev)
 
                 /*
                  * Redirect dma memory allocations to special memory window.
+                 *
+                 * If this GAPSPCI region were mapped by a BAR, the CPU
+                 * phys_addr_t would be pci_resource_start(), and the bus
+                 * address would be pci_bus_address(pci_resource_start()).
+                 * But apparently there's no BAR mapping it, so we just
+                 * "know" its CPU address is GAPSPCI_DMA_BASE.
                  */
+                res.start = GAPSPCI_DMA_BASE;
+                res.end = GAPSPCI_DMA_BASE + GAPSPCI_DMA_SIZE - 1;
+                res.flags = IORESOURCE_MEM;
+                pcibios_resource_to_bus(dev->bus, &region, &res);
                 BUG_ON(!dma_declare_coherent_memory(&dev->dev,
-                                                GAPSPCI_DMA_BASE,
-                                                GAPSPCI_DMA_BASE,
-                                                GAPSPCI_DMA_SIZE,
+                                                res.start,
+                                                region.start,
+                                                resource_size(&res),
                                                 DMA_MEMORY_MAP |
                                                 DMA_MEMORY_EXCLUSIVE));
                 break;