diff --git a/include/mmc.h b/include/mmc.h
index ed084c8..e0a56d9 100644
--- a/include/mmc.h
+++ b/include/mmc.h
@@ -96,6 +96,8 @@
 
 #define OCR_BUSY	0x80000000
 #define OCR_HCS		0x40000000
+#define OCR_VOLTAGE_MASK	0x007FFF80
+#define OCR_ACCESS_MODE		0x60000000
 
 #define MMC_STATUS_MASK		(~0x0206BF7F)
 #define MMC_STATUS_RDY_FOR_DATA (1<<8)