Re: [PATCH 0/4] Add framework to support clkout

From: Tushar Behera
Date: Mon May 12 2014 - 00:43:16 EST


On 05/10/2014 09:09 AM, Pankaj Dubey wrote:
> Hi Tushar,
>
[ ... ]
>> Also we need to find a suitable place to call early_syscon_init(), after
>> the device tree has been unflattened and before clock initialization.
>>
>> While testing, I called this before of_clk_init() in
>> arch/arm/kernel/time.c,
>> but that place is too generic. Calling anywhere from exynos.c is not
>> working ATM.
>
> IMO we do not need to, or if I am not wrong we should not change time.c.
>

The above solution is definitely a hack and just to test my stuff. The
below solution looks good.

> It's possible if we have exynos specific init_time with following changes.
> FYI, In my patch series for Exynos PMU [1], currently I am handling this in
> exynos_dt_machine_init. But definitely it can be handled as below and it
> works
> without any side effect and I have tested it. Only reason I do not
> adopted this
> as for Exynos PMU patch support I had other options. But if required and if
> following change is acceptable I can include this in my next version of
> Exynos
> PMU patch series.
>
> [1]: https://lkml.org/lkml/2014/4/30/18
>
>
> +static void __init exynos_init_time(void)
> +{
> + /* Nothing to do timer specific
> + * as early_syscon_init requires DT to be unflattened and
> + * system should be able to allocate memory we need to
> + * postpone until init_time, but it should be done before
> + * init_machine. Because before init_machine, secondary
> + * core boot starts and it uses PMU registers.
> + */
> +
> + exynos_map_pmu();
> +

Instead of calling early_syscon_init() from within exynos_map_pmu(), it
would be good to call it explicitly here before exynos_map_pmu().

> + of_clk_init(NULL);
> + clocksource_of_init();
> +
> +}
> +

--
Tushar Behera
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