drm/radeon/alpha: Add Alpha support to Radeon DRM code

Alpha needs to have available the system bus address for the Radeon's
local memory, so that it can be used in ttm_bo_vm_fault(), when building
the PTEs for accessing that VRAM.  So, we make bus.addr hold the ioremap()
return, and then we can modify bus.base appropriately for use during page
fault processing.
Signed-off-by: NJay Estabrook <jay.estabrook@gmail.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

drivers/gpu/drm/radeon/radeon_ttm.c

@@ -450,6 +450,29 @@ static int radeon_ttm_io_mem_reserve(struct ttm_bo_device *bdev, struct ttm_mem_
 			return -EINVAL;
 		mem->bus.base = rdev->mc.aper_base;
 		mem->bus.is_iomem = true;
+#ifdef __alpha__
+		/*
+		 * Alpha: use bus.addr to hold the ioremap() return,
+		 * so we can modify bus.base below.
+		 */
+		if (mem->placement & TTM_PL_FLAG_WC)
+			mem->bus.addr =
+				ioremap_wc(mem->bus.base + mem->bus.offset,
+					   mem->bus.size);
+		else
+			mem->bus.addr =
+				ioremap_nocache(mem->bus.base + mem->bus.offset,
+						mem->bus.size);
+
+		/*
+		 * Alpha: Use just the bus offset plus
+		 * the hose/domain memory base for bus.base.
+		 * It then can be used to build PTEs for VRAM
+		 * access, as done in ttm_bo_vm_fault().
+		 */
+		mem->bus.base = (mem->bus.base & 0x0ffffffffUL) +
+			rdev->ddev->hose->dense_mem_base;
+#endif
 		break;
 	default:
 		return -EINVAL;