[PATCH u-boot-marvell v2 1/2] arm: mvebu: spl: Add option to reset the board on DDR training failure

[Pali Rohár]

On Thursday 17 February 2022 13:54:42 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.
> 
> (If the DDR training fails while booting the image via UART, we will
>  still hang - it doesn't make sense to reset in such a case, because
>  after reset the board will try booting from another medium, and the
>  UART booting utility does not expect that.)
> 
> Signed-off-by: Marek Behún <marek.behun at nic.cz>

Reviewed-by: Pali Rohár <pali at kernel.org>

> ---
> Changes since v1:
> - dont reset if booting via UART, as suggested by Pali
> ---
>  arch/arm/mach-mvebu/Kconfig | 13 +++++++++++++
>  arch/arm/mach-mvebu/spl.c   |  7 ++++++-
>  2 files changed, 19 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm/mach-mvebu/Kconfig b/arch/arm/mach-mvebu/Kconfig
> index d23cc0c760..7d487f270b 100644
> --- a/arch/arm/mach-mvebu/Kconfig
> +++ b/arch/arm/mach-mvebu/Kconfig
> @@ -213,6 +213,19 @@ 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).
> +
> +	  Note that if booting via UART and the DDR training fails, the
> +	  device will still hang - it doesn't make sense to reset the board
> +	  in such a case.
> +
>  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..5ad323f9d9 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 +331,11 @@ 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) &&
> +		    get_boot_device() != BOOT_DEVICE_UART)
> +			reset_cpu();
> +		else
> +			hang();
>  	}
>  #endif
>  
> -- 
> 2.34.1
>