drm/radeon/kms: clean up some magic numbers

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@gmail.com>
diff --git a/drivers/gpu/drm/radeon/r300.c b/drivers/gpu/drm/radeon/r300.c
index cf862ca..55fe5ba 100644
--- a/drivers/gpu/drm/radeon/r300.c
+++ b/drivers/gpu/drm/radeon/r300.c
@@ -69,6 +69,9 @@
 	mb();
 }
 
+#define R300_PTE_WRITEABLE (1 << 2)
+#define R300_PTE_READABLE  (1 << 3)
+
 int rv370_pcie_gart_set_page(struct radeon_device *rdev, int i, uint64_t addr)
 {
 	void __iomem *ptr = (void *)rdev->gart.table.vram.ptr;
@@ -78,7 +81,7 @@
 	}
 	addr = (lower_32_bits(addr) >> 8) |
 	       ((upper_32_bits(addr) & 0xff) << 24) |
-	       0xc;
+	       R300_PTE_WRITEABLE | R300_PTE_READABLE;
 	/* on x86 we want this to be CPU endian, on powerpc
 	 * on powerpc without HW swappers, it'll get swapped on way
 	 * into VRAM - so no need for cpu_to_le32 on VRAM tables */
@@ -135,7 +138,7 @@
 	WREG32_PCIE(RADEON_PCIE_TX_DISCARD_RD_ADDR_LO, rdev->mc.vram_start);
 	WREG32_PCIE(RADEON_PCIE_TX_DISCARD_RD_ADDR_HI, 0);
 	/* Clear error */
-	WREG32_PCIE(0x18, 0);
+	WREG32_PCIE(RADEON_PCIE_TX_GART_ERROR, 0);
 	tmp = RREG32_PCIE(RADEON_PCIE_TX_GART_CNTL);
 	tmp |= RADEON_PCIE_TX_GART_EN;
 	tmp |= RADEON_PCIE_TX_GART_UNMAPPED_ACCESS_DISCARD;