mmc: sdio: fix setting card data bus width as 4-bit
SDIO_CCCR_IF[1:0] in SDIO card is used for card data bus width
setting as below:
00b: 1-bit bus
01b: Reserved
10b: 4-bit bus
11b: 8-bit bus (only for embedded SDIO)
And sdio_enable_wide is for setting data bus width as 4-bit.
But currently, it first reads the register, second OR' 1b with
SDIO_CCCR_IF[1], and then writes it back.
As we can see, this is based on such assumption that the
SDIO_CCCR_IF[0] is always 0. Apparently, this is not right.
Signed-off-by: Yong Ding <yongd@marvell.com>
Acked-by: Philip Rakity <prakity@marvell.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c
index 13d0e95..41c5fd8 100644
--- a/drivers/mmc/core/sdio.c
+++ b/drivers/mmc/core/sdio.c
@@ -218,6 +218,12 @@
if (ret)
return ret;
+ if ((ctrl & SDIO_BUS_WIDTH_MASK) == SDIO_BUS_WIDTH_RESERVED)
+ pr_warning("%s: SDIO_CCCR_IF is invalid: 0x%02x\n",
+ mmc_hostname(card->host), ctrl);
+
+ /* set as 4-bit bus width */
+ ctrl &= ~SDIO_BUS_WIDTH_MASK;
ctrl |= SDIO_BUS_WIDTH_4BIT;
ret = mmc_io_rw_direct(card, 1, 0, SDIO_CCCR_IF, ctrl, NULL);
diff --git a/include/linux/mmc/sdio.h b/include/linux/mmc/sdio.h
index c9fe66c..17446d3 100644
--- a/include/linux/mmc/sdio.h
+++ b/include/linux/mmc/sdio.h
@@ -98,7 +98,9 @@
#define SDIO_CCCR_IF 0x07 /* bus interface controls */
+#define SDIO_BUS_WIDTH_MASK 0x03 /* data bus width setting */
#define SDIO_BUS_WIDTH_1BIT 0x00
+#define SDIO_BUS_WIDTH_RESERVED 0x01
#define SDIO_BUS_WIDTH_4BIT 0x02
#define SDIO_BUS_ECSI 0x20 /* Enable continuous SPI interrupt */
#define SDIO_BUS_SCSI 0x40 /* Support continuous SPI interrupt */