[PATCH u-boot-marvell 1/2] arm: mvebu: spl: Add option to reset the board on DDR training failure

[Pali Rohár]

On Thursday 17 February 2022 01:08:48 Marek Behún wrote:
> From: Marek Behún <marek.behun at nic.cz>
> 
> Some boards may occacionally fail DDR training. Currently we hang() in
> this case. Add an option that makes the board do an immediate reset in
> such a case, so that a new training is tried as soon as possible,
> instead of hanging and possibly waiting for watchdog to reset the board.
> 
> Signed-off-by: Marek Behún <marek.behun at nic.cz>
> Reviewed-by: Stefan Roese <sr at denx.de>
> ---
>  arch/arm/mach-mvebu/Kconfig | 9 +++++++++
>  arch/arm/mach-mvebu/spl.c   | 6 +++++-
>  2 files changed, 14 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm/mach-mvebu/Kconfig b/arch/arm/mach-mvebu/Kconfig
> index d23cc0c760..ed957be6e1 100644
> --- a/arch/arm/mach-mvebu/Kconfig
> +++ b/arch/arm/mach-mvebu/Kconfig
> @@ -213,6 +213,15 @@ config DDR_LOG_LEVEL
>  	  At level 3, rovides the windows margin of each DQ as a results of
>  	  DQS centeralization.
>  
> +config DDR_RESET_ON_TRAINING_FAILURE
> +	bool "Reset the board on DDR training failure instead of hanging"
> +	depends on ARMADA_38X || ARMADA_XP
> +	help
> +	  If DDR training fails in SPL, reset the board instead of hanging.
> +	  Some boards are known to fail DDR training occasionally and an
> +	  immediate reset may be preferable to waiting until the board is
> +	  reset by watchdog (if there even is one).
> +
>  config SYS_BOARD
>  	default "clearfog" if TARGET_CLEARFOG
>  	default "helios4" if TARGET_HELIOS4
> diff --git a/arch/arm/mach-mvebu/spl.c b/arch/arm/mach-mvebu/spl.c
> index 273ecb8bd6..d3c3bdc74d 100644
> --- a/arch/arm/mach-mvebu/spl.c
> +++ b/arch/arm/mach-mvebu/spl.c
> @@ -4,6 +4,7 @@
>   */
>  
>  #include <common.h>
> +#include <cpu_func.h>
>  #include <dm.h>
>  #include <fdtdec.h>
>  #include <hang.h>
> @@ -330,7 +331,10 @@ void board_init_f(ulong dummy)
>  	ret = ddr3_init();
>  	if (ret) {
>  		printf("ddr3_init() failed: %d\n", ret);
> -		hang();
> +		if (IS_ENABLED(CONFIG_DDR_RESET_ON_TRAINING_FAILURE))
> +			reset_cpu();

You should not call reset_cpu() from SPL loaded via UART. This will
confuse x-modem software. Either return failure to BootROM or hang()
like it was before.

> +		else
> +			hang();
>  	}
>  #endif
>