[U-Boot] [PATCH] imx: save reset cause in 'reset_cause' environment variable

[Troy Kisky <troy.kisky@boundarydevices.com>]

On 2/5/2015 3:58 PM, Eric Nelson wrote:
> The cause of a reset is generally useful, and shouldn't be
> blindly cleared in the process of displaying it as a part
> of the boot announcement.
> 
> Stash the string representation in the environment variable
> "reset_cause".
> 
> Values include:
> 	"POR"		- power on reset
> 	"CSU"		- reset was the result of the csu_reset_b input
> 	"IPP-USER"	- ipp_user_reset_b qualified reset
> 	"WDOG"		- watchdog reset
> 	"JTAG-HIGH-Z"	- HIGH-Z reset from JTAG
> 	"JTAG-SW"	- software reset from JTAG
> 	"WARM-BOOT"	- WARM boot was initiated by software
> 
> Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>
> ---
>  arch/arm/imx-common/cpu.c | 25 ++++++++++++++++---------
>  1 file changed, 16 insertions(+), 9 deletions(-)
> 
> diff --git a/arch/arm/imx-common/cpu.c b/arch/arm/imx-common/cpu.c
> index 28ccd29..4a54051 100644
> --- a/arch/arm/imx-common/cpu.c
> +++ b/arch/arm/imx-common/cpu.c
> @@ -28,6 +28,7 @@ char *get_reset_cause(void)
>  {
>  	u32 cause;
>  	struct src *src_regs = (struct src *)SRC_BASE_ADDR;
> +	char *rval = "unknown";
>  
>  	cause = readl(&src_regs->srsr);
>  	writel(cause, &src_regs->srsr);
> @@ -35,22 +36,28 @@ char *get_reset_cause(void)
>  	switch (cause) {
>  	case 0x00001:
>  	case 0x00011:
> -		return "POR";
> +		rval = "POR";
> +		break;
>  	case 0x00004:
> -		return "CSU";
> +		rval = "CSU";
> +		break;
>  	case 0x00008:
> -		return "IPP USER";
> +		rval = "IPP-USER";
> +		break;
>  	case 0x00010:
> -		return "WDOG";
> +		rval = "WDOG";
> +		break;
>  	case 0x00020:
> -		return "JTAG HIGH-Z";
> +		rval = "JTAG-HIGH-Z";
> +		break;
>  	case 0x00040:
> -		return "JTAG SW";
> +		rval = "JTAG-SW";
> +		break;
>  	case 0x10000:
> -		return "WARM BOOT";
> -	default:
> -		return "unknown reset";
> +		rval = "WARM-BOOT";

Instead of removing default, can we have a hex value, something like
		sprintf(buf, "unknown(0x%x)", cause);

>  	}
> +	setenv("reset_cause", rval);
> +	return rval;
>  }
>  
>  #if defined(CONFIG_MX53) || defined(CONFIG_MX6)
>