linux-kernel - Re: [PATCH RFC 3/6] clk: meson: g12a: mark fclk

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Date:   Wed, 27 Mar 2019 11:51:42 +0100
From:   Jerome Brunet <jbrunet@...libre.com>
To:     Neil Armstrong <narmstrong@...libre.com>, khilman@...libre.com
Cc:     linux-amlogic@...ts.infradead.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-clk@...r.kernel.org
Subject: Re: [PATCH RFC 3/6] clk: meson: g12a: mark fclk_div3 as critical

On Wed, 2019-03-27 at 11:33 +0100, Neil Armstrong wrote:
> On Amlogic Meson G12b platform, the fclk_div3 seems to be necessary for
> the system to operate correctly.
> 
> Disabling it cause the entire system to freeze, including peripherals.
> 
> This patch patch marks this clock as critical, fixing boot on G12b platforms.
> 
> Signed-off-by: Neil Armstrong <narmstrong@...libre.com>
> ---
>  drivers/clk/meson/g12a.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/drivers/clk/meson/g12a.c b/drivers/clk/meson/g12a.c
> index 03b4c78f558f..d62ebcd2162d 100644
> --- a/drivers/clk/meson/g12a.c
> +++ b/drivers/clk/meson/g12a.c
> @@ -1062,6 +1062,16 @@ static struct clk_fixed_factor g12a_fclk_div3_div = {
>  		.ops = &clk_fixed_factor_ops,
>  		.parent_names = (const char *[]){ "fixed_pll" },
>  		.num_parents = 1,
> +		/*
> +		 * This clock is used by the resident firmware and is required
> +		 * by the platform to operate correctly.
> +		 * Until the following condition are met, we need this clock to
> +		 * be marked as critical:
> +		 * a) Mark the clock used by a firmware resource, if possible
> +		 * b) CCF has a clock hand-off mechanism to make the sure the
> +		 *    clock stays on until the proper driver comes along
> +		 */
> +		.flags = CLK_IS_CRITICAL,

The gate should be critical then, not the fixed_divider clock.
the fdiv3 gate is a child of this clock, so fdiv3 should still be able to gate
with this


>  	},
>  };
> 
>  

Could you CC me of the whole series next time, I prefer getting the all
context.