[PATCH] imx8qxp_mek: Start with USDHC2 unpowered

[Fabio Estevam <festevam@gmail.com>]

After triggering a "reboot" command in Linux the following
hang in SPL is observed:

U-Boot SPL 2020.04 (Apr 15 2020 - 10:49:29 -0300)
Normal Boot
WDT:   Not found!
Trying to boot from MMC2_2
spl: mmc init failed with error: -70
SPL: failed to boot from all boot devices
### ERROR ### Please RESET the board ###

This error happens because the CMD_ERR bit is set in the IRQ status
register after booting from Linux.

To ensure a fresh start, force the VMMC supply to get unpowered first.

Signed-off-by: Fabio Estevam <festevam@gmail.com>
---
 board/freescale/imx8qxp_mek/spl.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/board/freescale/imx8qxp_mek/spl.c b/board/freescale/imx8qxp_mek/spl.c
index cb4006eb2a..e4e4cbe716 100644
--- a/board/freescale/imx8qxp_mek/spl.c
+++ b/board/freescale/imx8qxp_mek/spl.c
@@ -12,9 +12,24 @@
 #include <dm/uclass-internal.h>
 #include <dm/device-internal.h>
 #include <dm/lists.h>
+#include <asm/io.h>
+#include <asm/gpio.h>
+#include <asm/arch/sci/sci.h>
+#include <asm/arch/imx8-pins.h>
+#include <asm/arch/iomux.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
+#define GPIO_PAD_CTRL	((SC_PAD_CONFIG_NORMAL << PADRING_CONFIG_SHIFT) | \
+			 (SC_PAD_ISO_OFF << PADRING_LPCONFIG_SHIFT) | \
+			 (SC_PAD_28FDSOI_DSE_DV_HIGH << PADRING_DSE_SHIFT) | \
+			 (SC_PAD_28FDSOI_PS_PU << PADRING_PULL_SHIFT))
+
+#define USDHC2_SD_PWR IMX_GPIO_NR(4, 19)
+static iomux_cfg_t usdhc2_sd_pwr[] = {
+	SC_P_USDHC1_RESET_B | MUX_PAD_CTRL(GPIO_PAD_CTRL),
+};
+
 void spl_board_init(void)
 {
 	struct udevice *dev;
@@ -32,6 +47,9 @@ void spl_board_init(void)
 
 	timer_init();
 
+	imx8_iomux_setup_multiple_pads(usdhc2_sd_pwr, ARRAY_SIZE(usdhc2_sd_pwr));
+	gpio_direction_output(USDHC2_SD_PWR, 0);
+
 	preloader_console_init();
 
 	puts("Normal Boot\n");
-- 
2.17.1