diff --git a/arch/mips/include/asm/pci/bridge.h b/arch/mips/include/asm/pci/bridge.h
index 8d7a63b..e54542f 100644
--- a/arch/mips/include/asm/pci/bridge.h
+++ b/arch/mips/include/asm/pci/bridge.h
@@ -790,10 +790,11 @@ typedef struct bridge_err_cmdword_s {
 /* 64-bit address attribute masks */
 #define PCI64_ATTR_TARG_MASK	0xf000000000000000
 #define PCI64_ATTR_TARG_SHFT	60
-#define PCI64_ATTR_PREF		0x0800000000000000
-#define PCI64_ATTR_PREC		0x0400000000000000
-#define PCI64_ATTR_VIRTUAL	0x0200000000000000
-#define PCI64_ATTR_BAR		0x0100000000000000
+#define PCI64_ATTR_PREF		0x0800000000000000 /* Prefetch */
+#define PCI64_ATTR_PREC		0x0400000000000000 /* Precise */
+#define PCI64_ATTR_VIRTUAL	0x0200000000000000 /* Virtual Request */
+#define PCI64_ATTR_BAR		0x0100000000000000 /* Barrier */
+#define PCI64_ATTR_SWAP		0x0080000000000000 /* Byte swapping (XBridge Only) */
 #define PCI64_ATTR_RMF_MASK	0x00ff000000000000
 #define PCI64_ATTR_RMF_SHFT	48