diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index 3832312..10b6979 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -495,6 +495,8 @@ static void dw_mci_submit_data(struct dw_mci *host, struct mmc_data *data)
 	if (dw_mci_submit_data_dma(host, data)) {
 		host->sg = data->sg;
 		host->pio_offset = 0;
+		host->part_buf_start = 0;
+		host->part_buf_count = 0;
 		if (data->flags & MMC_DATA_READ)
 			host->dir_status = DW_MCI_RECV_STATUS;
 		else
@@ -957,84 +959,278 @@ unlock:
 
 }
 
-static void dw_mci_push_data16(struct dw_mci *host, void *buf, int cnt)
+/* push final bytes to part_buf, only use during push */
+static void dw_mci_set_part_bytes(struct dw_mci *host, void *buf, int cnt)
 {
-	u16 *pdata = (u16 *)buf;
+	memcpy((void *)&host->part_buf, buf, cnt);
+	host->part_buf_count = cnt;
+}
 
-	WARN_ON(cnt % 2 != 0);
+/* append bytes to part_buf, only use during push */
+static int dw_mci_push_part_bytes(struct dw_mci *host, void *buf, int cnt)
+{
+	cnt = min(cnt, (1 << host->data_shift) - host->part_buf_count);
+	memcpy((void *)&host->part_buf + host->part_buf_count, buf, cnt);
+	host->part_buf_count += cnt;
+	return cnt;
+}
 
-	cnt = cnt >> 1;
-	while (cnt > 0) {
-		mci_writew(host, DATA, *pdata++);
-		cnt--;
+/* pull first bytes from part_buf, only use during pull */
+static int dw_mci_pull_part_bytes(struct dw_mci *host, void *buf, int cnt)
+{
+	cnt = min(cnt, (int)host->part_buf_count);
+	if (cnt) {
+		memcpy(buf, (void *)&host->part_buf + host->part_buf_start,
+		       cnt);
+		host->part_buf_count -= cnt;
+		host->part_buf_start += cnt;
 	}
+	return cnt;
 }
 
-static void dw_mci_pull_data16(struct dw_mci *host, void *buf, int cnt)
+/* pull final bytes from the part_buf, assuming it's just been filled */
+static void dw_mci_pull_final_bytes(struct dw_mci *host, void *buf, int cnt)
 {
-	u16 *pdata = (u16 *)buf;
+	memcpy(buf, &host->part_buf, cnt);
+	host->part_buf_start = cnt;
+	host->part_buf_count = (1 << host->data_shift) - cnt;
+}
 
-	WARN_ON(cnt % 2 != 0);
+static void dw_mci_push_data16(struct dw_mci *host, void *buf, int cnt)
+{
+	/* try and push anything in the part_buf */
+	if (unlikely(host->part_buf_count)) {
+		int len = dw_mci_push_part_bytes(host, buf, cnt);
+		buf += len;
+		cnt -= len;
+		if (!sg_next(host->sg) || host->part_buf_count == 2) {
+			mci_writew(host, DATA, host->part_buf16);
+			host->part_buf_count = 0;
+		}
+	}
+#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
+	if (unlikely((unsigned long)buf & 0x1)) {
+		while (cnt >= 2) {
+			u16 aligned_buf[64];
+			int len = min(cnt & -2, (int)sizeof(aligned_buf));
+			int items = len >> 1;
+			int i;
+			/* memcpy from input buffer into aligned buffer */
+			memcpy(aligned_buf, buf, len);
+			buf += len;
+			cnt -= len;
+			/* push data from aligned buffer into fifo */
+			for (i = 0; i < items; ++i)
+				mci_writew(host, DATA, aligned_buf[i]);
+		}
+	} else
+#endif
+	{
+		u16 *pdata = buf;
+		for (; cnt >= 2; cnt -= 2)
+			mci_writew(host, DATA, *pdata++);
+		buf = pdata;
+	}
+	/* put anything remaining in the part_buf */
+	if (cnt) {
+		dw_mci_set_part_bytes(host, buf, cnt);
+		if (!sg_next(host->sg))
+			mci_writew(host, DATA, host->part_buf16);
+	}
+}
 
-	cnt = cnt >> 1;
-	while (cnt > 0) {
-		*pdata++ = mci_readw(host, DATA);
-		cnt--;
+static void dw_mci_pull_data16(struct dw_mci *host, void *buf, int cnt)
+{
+#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
+	if (unlikely((unsigned long)buf & 0x1)) {
+		while (cnt >= 2) {
+			/* pull data from fifo into aligned buffer */
+			u16 aligned_buf[64];
+			int len = min(cnt & -2, (int)sizeof(aligned_buf));
+			int items = len >> 1;
+			int i;
+			for (i = 0; i < items; ++i)
+				aligned_buf[i] = mci_readw(host, DATA);
+			/* memcpy from aligned buffer into output buffer */
+			memcpy(buf, aligned_buf, len);
+			buf += len;
+			cnt -= len;
+		}
+	} else
+#endif
+	{
+		u16 *pdata = buf;
+		for (; cnt >= 2; cnt -= 2)
+			*pdata++ = mci_readw(host, DATA);
+		buf = pdata;
+	}
+	if (cnt) {
+		host->part_buf16 = mci_readw(host, DATA);
+		dw_mci_pull_final_bytes(host, buf, cnt);
 	}
 }
 
 static void dw_mci_push_data32(struct dw_mci *host, void *buf, int cnt)
 {
-	u32 *pdata = (u32 *)buf;
-
-	WARN_ON(cnt % 4 != 0);
-	WARN_ON((unsigned long)pdata & 0x3);
-
-	cnt = cnt >> 2;
-	while (cnt > 0) {
-		mci_writel(host, DATA, *pdata++);
-		cnt--;
+	/* try and push anything in the part_buf */
+	if (unlikely(host->part_buf_count)) {
+		int len = dw_mci_push_part_bytes(host, buf, cnt);
+		buf += len;
+		cnt -= len;
+		if (!sg_next(host->sg) || host->part_buf_count == 4) {
+			mci_writel(host, DATA, host->part_buf32);
+			host->part_buf_count = 0;
+		}
+	}
+#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
+	if (unlikely((unsigned long)buf & 0x3)) {
+		while (cnt >= 4) {
+			u32 aligned_buf[32];
+			int len = min(cnt & -4, (int)sizeof(aligned_buf));
+			int items = len >> 2;
+			int i;
+			/* memcpy from input buffer into aligned buffer */
+			memcpy(aligned_buf, buf, len);
+			buf += len;
+			cnt -= len;
+			/* push data from aligned buffer into fifo */
+			for (i = 0; i < items; ++i)
+				mci_writel(host, DATA, aligned_buf[i]);
+		}
+	} else
+#endif
+	{
+		u32 *pdata = buf;
+		for (; cnt >= 4; cnt -= 4)
+			mci_writel(host, DATA, *pdata++);
+		buf = pdata;
+	}
+	/* put anything remaining in the part_buf */
+	if (cnt) {
+		dw_mci_set_part_bytes(host, buf, cnt);
+		if (!sg_next(host->sg))
+			mci_writel(host, DATA, host->part_buf32);
 	}
 }
 
 static void dw_mci_pull_data32(struct dw_mci *host, void *buf, int cnt)
 {
-	u32 *pdata = (u32 *)buf;
-
-	WARN_ON(cnt % 4 != 0);
-	WARN_ON((unsigned long)pdata & 0x3);
-
-	cnt = cnt >> 2;
-	while (cnt > 0) {
-		*pdata++ = mci_readl(host, DATA);
-		cnt--;
+#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
+	if (unlikely((unsigned long)buf & 0x3)) {
+		while (cnt >= 4) {
+			/* pull data from fifo into aligned buffer */
+			u32 aligned_buf[32];
+			int len = min(cnt & -4, (int)sizeof(aligned_buf));
+			int items = len >> 2;
+			int i;
+			for (i = 0; i < items; ++i)
+				aligned_buf[i] = mci_readl(host, DATA);
+			/* memcpy from aligned buffer into output buffer */
+			memcpy(buf, aligned_buf, len);
+			buf += len;
+			cnt -= len;
+		}
+	} else
+#endif
+	{
+		u32 *pdata = buf;
+		for (; cnt >= 4; cnt -= 4)
+			*pdata++ = mci_readl(host, DATA);
+		buf = pdata;
+	}
+	if (cnt) {
+		host->part_buf32 = mci_readl(host, DATA);
+		dw_mci_pull_final_bytes(host, buf, cnt);
 	}
 }
 
 static void dw_mci_push_data64(struct dw_mci *host, void *buf, int cnt)
 {
-	u64 *pdata = (u64 *)buf;
-
-	WARN_ON(cnt % 8 != 0);
-
-	cnt = cnt >> 3;
-	while (cnt > 0) {
-		mci_writeq(host, DATA, *pdata++);
-		cnt--;
+	/* try and push anything in the part_buf */
+	if (unlikely(host->part_buf_count)) {
+		int len = dw_mci_push_part_bytes(host, buf, cnt);
+		buf += len;
+		cnt -= len;
+		if (!sg_next(host->sg) || host->part_buf_count == 8) {
+			mci_writew(host, DATA, host->part_buf);
+			host->part_buf_count = 0;
+		}
+	}
+#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
+	if (unlikely((unsigned long)buf & 0x7)) {
+		while (cnt >= 8) {
+			u64 aligned_buf[16];
+			int len = min(cnt & -8, (int)sizeof(aligned_buf));
+			int items = len >> 3;
+			int i;
+			/* memcpy from input buffer into aligned buffer */
+			memcpy(aligned_buf, buf, len);
+			buf += len;
+			cnt -= len;
+			/* push data from aligned buffer into fifo */
+			for (i = 0; i < items; ++i)
+				mci_writeq(host, DATA, aligned_buf[i]);
+		}
+	} else
+#endif
+	{
+		u64 *pdata = buf;
+		for (; cnt >= 8; cnt -= 8)
+			mci_writeq(host, DATA, *pdata++);
+		buf = pdata;
+	}
+	/* put anything remaining in the part_buf */
+	if (cnt) {
+		dw_mci_set_part_bytes(host, buf, cnt);
+		if (!sg_next(host->sg))
+			mci_writeq(host, DATA, host->part_buf);
 	}
 }
 
 static void dw_mci_pull_data64(struct dw_mci *host, void *buf, int cnt)
 {
-	u64 *pdata = (u64 *)buf;
+#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
+	if (unlikely((unsigned long)buf & 0x7)) {
+		while (cnt >= 8) {
+			/* pull data from fifo into aligned buffer */
+			u64 aligned_buf[16];
+			int len = min(cnt & -8, (int)sizeof(aligned_buf));
+			int items = len >> 3;
+			int i;
+			for (i = 0; i < items; ++i)
+				aligned_buf[i] = mci_readq(host, DATA);
+			/* memcpy from aligned buffer into output buffer */
+			memcpy(buf, aligned_buf, len);
+			buf += len;
+			cnt -= len;
+		}
+	} else
+#endif
+	{
+		u64 *pdata = buf;
+		for (; cnt >= 8; cnt -= 8)
+			*pdata++ = mci_readq(host, DATA);
+		buf = pdata;
+	}
+	if (cnt) {
+		host->part_buf = mci_readq(host, DATA);
+		dw_mci_pull_final_bytes(host, buf, cnt);
+	}
+}
+
+static void dw_mci_pull_data(struct dw_mci *host, void *buf, int cnt)
+{
+	int len;
 
-	WARN_ON(cnt % 8 != 0);
+	/* get remaining partial bytes */
+	len = dw_mci_pull_part_bytes(host, buf, cnt);
+	if (unlikely(len == cnt))
+		return;
+	buf += len;
+	cnt -= len;
 
-	cnt = cnt >> 3;
-	while (cnt > 0) {
-		*pdata++ = mci_readq(host, DATA);
-		cnt--;
-	}
+	/* get the rest of the data */
+	host->pull_data(host, buf, cnt);
 }
 
 static void dw_mci_read_data_pio(struct dw_mci *host)
@@ -1048,9 +1244,10 @@ static void dw_mci_read_data_pio(struct dw_mci *host)
 	unsigned int nbytes = 0, len;
 
 	do {
-		len = SDMMC_GET_FCNT(mci_readl(host, STATUS)) << shift;
+		len = host->part_buf_count +
+			(SDMMC_GET_FCNT(mci_readl(host, STATUS)) << shift);
 		if (offset + len <= sg->length) {
-			host->pull_data(host, (void *)(buf + offset), len);
+			dw_mci_pull_data(host, (void *)(buf + offset), len);
 
 			offset += len;
 			nbytes += len;
@@ -1066,8 +1263,8 @@ static void dw_mci_read_data_pio(struct dw_mci *host)
 			}
 		} else {
 			unsigned int remaining = sg->length - offset;
-			host->pull_data(host, (void *)(buf + offset),
-					remaining);
+			dw_mci_pull_data(host, (void *)(buf + offset),
+					 remaining);
 			nbytes += remaining;
 
 			flush_dcache_page(sg_page(sg));
@@ -1077,7 +1274,7 @@ static void dw_mci_read_data_pio(struct dw_mci *host)
 
 			offset = len - remaining;
 			buf = sg_virt(sg);
-			host->pull_data(host, buf, offset);
+			dw_mci_pull_data(host, buf, offset);
 			nbytes += offset;
 		}
 
@@ -1094,7 +1291,6 @@ static void dw_mci_read_data_pio(struct dw_mci *host)
 			return;
 		}
 	} while (status & SDMMC_INT_RXDR); /*if the RXDR is ready read again*/
-	len = SDMMC_GET_FCNT(mci_readl(host, STATUS));
 	host->pio_offset = offset;
 	data->bytes_xfered += nbytes;
 	return;
@@ -1116,8 +1312,9 @@ static void dw_mci_write_data_pio(struct dw_mci *host)
 	unsigned int nbytes = 0, len;
 
 	do {
-		len = (host->fifo_depth -
-			SDMMC_GET_FCNT(mci_readl(host, STATUS))) << shift;
+		len = ((host->fifo_depth -
+			SDMMC_GET_FCNT(mci_readl(host, STATUS))) << shift)
+			- host->part_buf_count;
 		if (offset + len <= sg->length) {
 			host->push_data(host, (void *)(buf + offset), len);
 
@@ -1162,10 +1359,8 @@ static void dw_mci_write_data_pio(struct dw_mci *host)
 			return;
 		}
 	} while (status & SDMMC_INT_TXDR); /* if TXDR write again */
-
 	host->pio_offset = offset;
 	data->bytes_xfered += nbytes;
-
 	return;
 
 done:
diff --git a/include/linux/mmc/dw_mmc.h b/include/linux/mmc/dw_mmc.h
index 01db1a0..f3f68ee 100644
--- a/include/linux/mmc/dw_mmc.h
+++ b/include/linux/mmc/dw_mmc.h
@@ -76,6 +76,9 @@ struct mmc_data;
  * @slot: Slots sharing this MMC controller.
  * @fifo_depth: depth of FIFO.
  * @data_shift: log2 of FIFO item size.
+ * @part_buf_start: Start index in part_buf.
+ * @part_buf_count: Bytes of partial data in part_buf.
+ * @part_buf: Simple buffer for partial fifo reads/writes.
  * @push_data: Pointer to FIFO push function.
  * @pull_data: Pointer to FIFO pull function.
  * @quirks: Set of quirks that apply to specific versions of the IP.
@@ -149,6 +152,13 @@ struct dw_mci {
 	/* FIFO push and pull */
 	int			fifo_depth;
 	int			data_shift;
+	u8			part_buf_start;
+	u8			part_buf_count;
+	union {
+		u16		part_buf16;
+		u32		part_buf32;
+		u64		part_buf;
+	};
 	void (*push_data)(struct dw_mci *host, void *buf, int cnt);
 	void (*pull_data)(struct dw_mci *host, void *buf, int cnt);
 
