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Subject: Re: [PATCH RFC 3/6] clk: meson: g12a: mark fclk_div3 as critical
To:     Jerome Brunet <jbrunet@baylibre.com>, khilman@baylibre.com
Cc:     linux-amlogic@lists.infradead.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-clk@vger.kernel.org
References: <20190327103308.25058-1-narmstrong@baylibre.com>
 <20190327103308.25058-4-narmstrong@baylibre.com>
 <345dd7e287ed07f4a84847ff024fce237c1380a1.camel@baylibre.com>
From:   Neil Armstrong <narmstrong@baylibre.com>
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Organization: Baylibre
Message-ID: <75f4b557-ad02-9948-7c01-cd9c1988c6c1@baylibre.com>
Date:   Thu, 4 Apr 2019 16:51:07 +0200
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Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On 27/03/2019 11:51, Jerome Brunet wrote:
> 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@baylibre.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

Weird, because with this, it's removed from the unused clocks list... will move to the gate.

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

Sure