[U-Boot] [PATCH] pico-imx6ul: Fix eMMC boot after DM_MMC conversion

Lukasz Majewski
2019-03-27T09:23:02Z

Hi Fabio,

> After the DM_MMC conversion the following eMMC boot error is observed:
>
> U-Boot SPL 2019.04-rc4 (Mar 20 2019 - 18:53:28 +0000)
> Trying to boot from MMC1
> MMC Device 0 not found
> spl: could not find mmc device 0. error: -19
> SPL: failed to boot from all boot devices
> ### ERROR ### Please RESET the board ###
>
> This happens because the SPL code does not initialize the SDHC pins
> and clock.
>
> Fix it by moving the original eMMC initialization from U-Boot proper
> to SPL.
>
> Reported-by: Otavio Salvador <otavio@ossystems.com.br>
> Signed-off-by: Fabio Estevam <festevam@gmail.com>
> Tested-by: Fabio Berton <fabio.berton@ossystems.com.br>
> Reviewed-by: Otavio Salvador <otavio@ossystems.com.br>
> ---
> board/technexion/pico-imx6ul/spl.c | 34
> ++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+)
>
> diff --git a/board/technexion/pico-imx6ul/spl.c
> b/board/technexion/pico-imx6ul/spl.c index 6464a32d3b..f972cc9eaf
> 100644 --- a/board/technexion/pico-imx6ul/spl.c
> +++ b/board/technexion/pico-imx6ul/spl.c
> @@ -10,6 +10,7 @@
> #include <asm/gpio.h>
> #include <asm/mach-imx/iomux-v3.h>
> #include <asm/mach-imx/boot_mode.h>
> +#include <fsl_esdhc.h>
> #include <linux/libfdt.h>
> #include <spl.h>
>
> @@ -141,4 +142,37 @@ void board_init_f(ulong dummy)
> void reset_cpu(ulong addr)
> {
> }
> +
> +#define USDHC_PAD_CTRL (PAD_CTL_PKE | PAD_CTL_PUE | \
> + PAD_CTL_PUS_22K_UP | PAD_CTL_SPEED_LOW | \
> + PAD_CTL_DSE_80ohm | PAD_CTL_SRE_FAST | PAD_CTL_HYS)
> +
> +static iomux_v3_cfg_t const usdhc1_pads[] = {
> + MX6_PAD_SD1_CLK__USDHC1_CLK | MUX_PAD_CTRL(USDHC_PAD_CTRL),
> + MX6_PAD_SD1_CMD__USDHC1_CMD | MUX_PAD_CTRL(USDHC_PAD_CTRL),
> + MX6_PAD_SD1_DATA0__USDHC1_DATA0 |
> MUX_PAD_CTRL(USDHC_PAD_CTRL),
> + MX6_PAD_SD1_DATA1__USDHC1_DATA1 |
> MUX_PAD_CTRL(USDHC_PAD_CTRL),
> + MX6_PAD_SD1_DATA2__USDHC1_DATA2 |
> MUX_PAD_CTRL(USDHC_PAD_CTRL),
> + MX6_PAD_SD1_DATA3__USDHC1_DATA3 |
> MUX_PAD_CTRL(USDHC_PAD_CTRL),
> + MX6_PAD_NAND_READY_B__USDHC1_DATA4 |
> MUX_PAD_CTRL(USDHC_PAD_CTRL),
> + MX6_PAD_NAND_CE0_B__USDHC1_DATA5 |
> MUX_PAD_CTRL(USDHC_PAD_CTRL),
> + MX6_PAD_NAND_CE1_B__USDHC1_DATA6 |
> MUX_PAD_CTRL(USDHC_PAD_CTRL),
> + MX6_PAD_NAND_CLE__USDHC1_DATA7 |
> MUX_PAD_CTRL(USDHC_PAD_CTRL), +};
> +
> +static struct fsl_esdhc_cfg usdhc_cfg[1] = {
> + {USDHC1_BASE_ADDR},
> +};
> +
> +int board_mmc_getcd(struct mmc *mmc)
> +{
> + return 1;
> +}
> +
> +int board_mmc_init(bd_t *bis)
> +{
> + imx_iomux_v3_setup_multiple_pads(usdhc1_pads,
> ARRAY_SIZE(usdhc1_pads));
> + usdhc_cfg[0].sdhc_clk = mxc_get_clock(MXC_ESDHC_CLK);
> + return fsl_esdhc_initialize(bis, &usdhc_cfg[0]);
> +}
> #endif

This seems like a temporary solution - the u-boot proper is converted
to use DM_MMC, but the pinmux setup code is moved to SPL instead.

The proper solution would be to add support for pinmux in SPL and
setup those pins there.

Something similar to:
http://patchwork.ozlabs.org/cover/1019842/

But this patch series shall not be regarded as a template for the
conversion as some of those patches have been superseded (like clock
with CCF clock, FEC setup).

However, the pinctrl/eMMC shall be a good example.

The other question is if imx6ul has enough resources to use such
feature-rich SPL.

Best regards,

Lukasz Majewski

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