[U-Boot] [PATCH resend] at91: Enable slow master clock on meesc board
Tom
Tom.Rix at windriver.com
Wed Nov 25 22:02:43 CET 2009
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 at 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
>
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