diff --git a/drivers/mmc/host/at91_mci.c b/drivers/mmc/host/at91_mci.c
index 63924e0c7ea9a6c3fab8c2b38857be8832149612..4e1b2e6288dae295a1fb2e1a8699823515d6e163 100644
--- a/drivers/mmc/host/at91_mci.c
+++ b/drivers/mmc/host/at91_mci.c
@@ -227,11 +227,13 @@ static inline void at91_mci_sg_to_dma(struct at91mci_host *host, struct mmc_data
 			for (index = 0; index < (amount / 4); index++)
 				*dmabuf++ = swab32(sgbuffer[index]);
 		} else {
-			memcpy(dmabuf, sgbuffer, amount);
-			dmabuf += amount;
+			char *tmpv = (char *)dmabuf;
+			memcpy(tmpv, sgbuffer, amount);
+			tmpv += amount;
+			dmabuf = (unsigned *)tmpv;
 		}
 
-		kunmap_atomic(sgbuffer, KM_BIO_SRC_IRQ);
+		kunmap_atomic(((void *)sgbuffer) - sg->offset, KM_BIO_SRC_IRQ);
 
 		if (size == 0)
 			break;