[PATCH 4/5] mmc: mmci: Fix PIO read for small SDIO packets

[Ulf Hansson]

From: Stefan Nilsson XK <stefan.xk.nilsson at stericsson.com>

Corrects a bug in MMCI host driver which silently causes
small reads (< 4 bytes as only used in SDIO) from PL-18X to fail.

Signed-off-by: Stefan Nilsson XK <stefan.xk.nilsson at stericsson.com>
Signed-off-by: Ulf Hansson <ulf.hansson at stericsson.com>
Signed-off-by: Fredrik Soderstedt <fredrik.soderstedt at stericsson.com>
---
 drivers/mmc/host/mmci.c |   19 ++++++++++++++++++-
 1 files changed, 18 insertions(+), 1 deletions(-)

diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
index 9ea2f13..94c04c3 100644
--- a/drivers/mmc/host/mmci.c
+++ b/drivers/mmc/host/mmci.c
@@ -876,7 +876,24 @@ static int mmci_pio_read(struct mmci_host *host, char *buffer, unsigned int rema
 		if (count <= 0)
 			break;
 
-		readsl(base + MMCIFIFO, ptr, count >> 2);
+		/*
+		 * SDIO especially may want to send something that is
+		 * not divisible by 4 (as opposed to card sectors
+		 * etc). Therefore make sure to always read the last bytes
+		 * while only doing full 32-bit reads towards the FIFO.
+		 */
+		if (unlikely(count & 0x3)) {
+			if (count < 4) {
+				unsigned char buf[4];
+				readsl(base + MMCIFIFO, buf, 1);
+				memcpy(ptr, buf, count);
+			} else {
+				readsl(base + MMCIFIFO, ptr, count >> 2);
+				count &= ~0x3;
+			}
+		} else {
+			readsl(base + MMCIFIFO, ptr, count >> 2);
+		}
 
 		ptr += count;
 		remain -= count;
-- 
1.7.5.4