[U-Boot] [PATCH resend] at91: Enable slow master clock on meesc board

[Tom <Tom.Rix@windriver.com>]

Daniel Gorsulowski wrote:
> In some cases, we need low speed master clock. So depending on the
> "mdiv" variable, the processor clock is divided by 2 (default) or 4.
> 
> Signed-off-by: Daniel Gorsulowski <Daniel.Gorsulowski@esd.eu>
> ---
>  board/esd/meesc/meesc.c |   24 ++++++++++++++++++++++++
>  include/configs/meesc.h |    1 +
>  2 files changed, 25 insertions(+), 0 deletions(-)
> 
> diff --git a/board/esd/meesc/meesc.c b/board/esd/meesc/meesc.c
> index efba60d..4f6c5b7 100644
> --- a/board/esd/meesc/meesc.c
> +++ b/board/esd/meesc/meesc.c
> @@ -219,6 +219,30 @@ u32 get_board_rev(void)
>  }
>  #endif
>  
> +#ifdef CONFIG_MISC_INIT_R
> +int misc_init_r(void)
> +{
> +	char *str;
> +	char buf[32];
> +
> +	/*
> +	 * In some cases, we need low speed master clock. So depending on the
> +	 * "mdiv" variable, the processor clock is divided by 2 (default) or 4.
> +	 */
This comment does not follow what is done.
 From the comment there should be an 'else' branch where the mdiv_2 is
done.

> +	if ((str = getenv("mdiv")) && (!strcmp(str, "4"))) {

Move the getenv out of the if-check.
The string comparision should be strengthened. str = "44" would be valid.
Perhaps warn if the expected 2 or 4 is not set.

There are more that 2 and 4 possible clk divisors.
Do you want to make this function more general?

> +		at91_sys_write(AT91_PMC_MCKR,
> +			(at91_sys_read(AT91_PMC_MCKR) & ~AT91_PMC_MDIV) |
> +			AT91SAM9_PMC_MDIV_4);
> +		at91_clock_init(0);
> +		serial_setbrg();
> +		printf("Setting master clock to %s MHz\n",
> +			strmhz(buf, get_mck_clk_rate()));
This printf should be moved outside of the if check so the default
case also gets the printout.

Tom

> +	}
> +
> +	return 0;
> +}
> +#endif /* CONFIG_MISC_INIT_R */
> +
>  int board_init(void)
>  {
>  	/* Peripheral Clock Enable Register */
> diff --git a/include/configs/meesc.h b/include/configs/meesc.h
> index b996854..034e81c 100644
> --- a/include/configs/meesc.h
> +++ b/include/configs/meesc.h
> @@ -48,6 +48,7 @@
>  
>  #define CONFIG_SKIP_LOWLEVEL_INIT
>  #define CONFIG_SKIP_RELOCATE_UBOOT
> +#define CONFIG_MISC_INIT_R			/* Call misc_init_r */
>  
>  #define CONFIG_ARCH_CPU_INIT
>