[U-Boot] [PATCH v2] mmc: i.MX6: fsl_esdhc: Define maximum bus width supported by a board

[Abbas Raza]

From: Abbas Raza <Abbas_Raza at mentor.com>

Maximum bus width supported by some i.MX6 boards is not 8bit like
others. In case where both host controller and card support 8bit transfers,
they agree to communicate on 8bit interface while some boards support only 4bit interface.
Due to this reason the mmc 8bit default mode fails on these boards. To rectify this,
define maximum bus width supported by these boards (4bit). If max_bus_width is not
defined, it is 0 by default and 8bit width support will be enabled in host
capabilities otherwise host capabilities are modified accordingly.

It is tested with a MMCplus card.

Signed-off-by: Abbas Raza <Abbas_Raza at mentor.com>
cc: stefano Babic <sbabic at denx.de>
cc: Andy Fleming <afleming at gmail.com>
Acked-by: Dirk Behme <dirk.behme at de.bosch.com>
Acked-by: Andrew Gabbasov <andrew_gabbasov at mentor.com>
---
Changes for v2:
   - Added support for nitrogen6x, wandboard boards

 board/boundary/nitrogen6x/nitrogen6x.c        | 3 +++
 board/freescale/mx6qsabrelite/mx6qsabrelite.c | 3 +++
 board/wandboard/wandboard.c                   | 2 ++
 drivers/mmc/fsl_esdhc.c                       | 7 +++++++
 include/fsl_esdhc.h                           | 1 +
 5 files changed, 16 insertions(+)

diff --git a/board/boundary/nitrogen6x/nitrogen6x.c b/board/boundary/nitrogen6x/nitrogen6x.c
index 229c237..e5b7795 100644
--- a/board/boundary/nitrogen6x/nitrogen6x.c
+++ b/board/boundary/nitrogen6x/nitrogen6x.c
@@ -304,6 +304,9 @@ int board_mmc_init(bd_t *bis)
 	usdhc_cfg[0].sdhc_clk = mxc_get_clock(MXC_ESDHC3_CLK);
 	usdhc_cfg[1].sdhc_clk = mxc_get_clock(MXC_ESDHC4_CLK);
 
+	usdhc_cfg[0].max_bus_width = 4;
+	usdhc_cfg[1].max_bus_width = 4;
+
 	for (index = 0; index < CONFIG_SYS_FSL_USDHC_NUM; ++index) {
 		switch (index) {
 		case 0:
diff --git a/board/freescale/mx6qsabrelite/mx6qsabrelite.c b/board/freescale/mx6qsabrelite/mx6qsabrelite.c
index 5b69a6d..0e25613 100644
--- a/board/freescale/mx6qsabrelite/mx6qsabrelite.c
+++ b/board/freescale/mx6qsabrelite/mx6qsabrelite.c
@@ -274,6 +274,9 @@ int board_mmc_init(bd_t *bis)
 	usdhc_cfg[0].sdhc_clk = mxc_get_clock(MXC_ESDHC3_CLK);
 	usdhc_cfg[1].sdhc_clk = mxc_get_clock(MXC_ESDHC4_CLK);
 
+	usdhc_cfg[0].max_bus_width = 4;
+	usdhc_cfg[1].max_bus_width = 4;
+
 	for (index = 0; index < CONFIG_SYS_FSL_USDHC_NUM; ++index) {
 		switch (index) {
 		case 0:
diff --git a/board/wandboard/wandboard.c b/board/wandboard/wandboard.c
index d95189f..8d071e1 100644
--- a/board/wandboard/wandboard.c
+++ b/board/wandboard/wandboard.c
@@ -105,6 +105,8 @@ int board_mmc_init(bd_t *bis)
 	imx_iomux_v3_setup_multiple_pads(usdhc3_pads, ARRAY_SIZE(usdhc3_pads));
 
 	usdhc_cfg[0].sdhc_clk = mxc_get_clock(MXC_ESDHC3_CLK);
+	usdhc_cfg[0].max_bus_width = 4;
+
 	return fsl_esdhc_initialize(bis, &usdhc_cfg[0]);
 }
 
diff --git a/drivers/mmc/fsl_esdhc.c b/drivers/mmc/fsl_esdhc.c
index 54b5363..35f879e 100644
--- a/drivers/mmc/fsl_esdhc.c
+++ b/drivers/mmc/fsl_esdhc.c
@@ -580,6 +580,13 @@ int fsl_esdhc_initialize(bd_t *bis, struct fsl_esdhc_cfg *cfg)
 
 	mmc->host_caps = MMC_MODE_4BIT | MMC_MODE_8BIT | MMC_MODE_HC;
 
+	if (cfg->max_bus_width > 0) {
+		if (cfg->max_bus_width < 8)
+			mmc->host_caps &= ~MMC_MODE_8BIT;
+		if (cfg->max_bus_width < 4)
+			mmc->host_caps &= ~MMC_MODE_4BIT;
+	}
+
 	if (caps & ESDHC_HOSTCAPBLT_HSS)
 		mmc->host_caps |= MMC_MODE_HS_52MHz | MMC_MODE_HS;
 
diff --git a/include/fsl_esdhc.h b/include/fsl_esdhc.h
index 47d2fe4..0a1a071 100644
--- a/include/fsl_esdhc.h
+++ b/include/fsl_esdhc.h
@@ -168,6 +168,7 @@
 struct fsl_esdhc_cfg {
 	u32	esdhc_base;
 	u32	sdhc_clk;
+	u8	max_bus_width;
 };
 
 /* Select the correct accessors depending on endianess */
-- 
1.8.2