agp: Support 64-bit APBASE

Per the AGP 3.0 spec, APBASE is a standard PCI BAR and may be either 32
bits or 64 bits wide.  Many drivers read APBASE directly, but they only
handled 32-bit BARs.

The PCI core reads APBASE at enumeration-time.  Use pci_bus_address()
instead of reading it again in the driver.  This works correctly for both
32-bit and 64-bit BARs.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/char/agp/efficeon-agp.c b/drivers/char/agp/efficeon-agp.c
index 6974d50..533cb6d 100644
--- a/drivers/char/agp/efficeon-agp.c
+++ b/drivers/char/agp/efficeon-agp.c
@@ -128,7 +128,6 @@
 
 static int efficeon_configure(void)
 {
-	u32 temp;
 	u16 temp2;
 	struct aper_size_info_lvl2 *current_size;
 
@@ -141,8 +140,8 @@
 			      current_size->size_value);
 
 	/* address to map to */
-	pci_read_config_dword(agp_bridge->dev, AGP_APBASE, &temp);
-	agp_bridge->gart_bus_addr = (temp & PCI_BASE_ADDRESS_MEM_MASK);
+	agp_bridge->gart_bus_addr = pci_bus_address(agp_bridge->dev,
+						    AGP_APERTURE_BAR);
 
 	/* agpctrl */
 	pci_write_config_dword(agp_bridge->dev, INTEL_AGPCTRL, 0x2280);