From: Anand Moon <linux.amoon@gmail.com>
To: Jerome Brunet <jbrunet@baylibre.com>
Cc: Rob Herring <robh+dt@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Neil Armstrong <narmstrong@baylibre.com>,
Martin Blumenstingl <martin.blumenstingl@googlemail.com>,
Michael Turquette <mturquette@baylibre.com>,
Stephen Boyd <sboyd@kernel.org>,
Kevin Hilman <khilman@baylibre.com>,
devicetree <devicetree@vger.kernel.org>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
linux-amlogic@lists.infradead.org,
Linux Kernel <linux-kernel@vger.kernel.org>,
"open list:COMMON CLK FRAMEWORK" <linux-clk@vger.kernel.org>
Subject: Re: [PATCHv1 3/3] clk: meson: g12a: set cpu clock divider flags too CLK_IS_CRITICAL
Date: Mon, 17 Feb 2020 14:21:29 +0530 [thread overview]
Message-ID: <CANAwSgRurj6Mfkqq6OfW_ZORCj_UhQN24kx-tj+sUWfuqn_uoQ@mail.gmail.com> (raw)
In-Reply-To: <1jmu9hzlo2.fsf@starbuckisacylon.baylibre.com>
Hi Jerome,
Thanks for your review comments.
On Mon, 17 Feb 2020 at 13:32, Jerome Brunet <jbrunet@baylibre.com> wrote:
>
>
> On Sun 16 Feb 2020 at 18:34, Anand Moon <linux.amoon@gmail.com> wrote:
>
> > Odroid N2 would fail to boot using microSD unless we set
> > cpu freq clk divider flags to CLK_IS_CRITICAL to avoid stalling of
> > cpu when booting, most likely because of PWM module linked to
>
> Where did you see a PWM ?
>
> > the CPU for DVFS is getting disabled in between the late_init call,
>
> between the late_init call and what ?
>
> > so gaiting the clock source shuts down the power to the codes.
>
> what code ?
>
> > Setting clk divider flags to CLK_IS_CRITICAL help resolve the issue.
> >
> > Cc: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
> > Cc: Jerome Brunet <jbrunet@baylibre.com>
> > Cc: Neil Armstrong <narmstrong@baylibre.com>
> > Suggested-by: Neil Armstrong <narmstrong@baylibre.com>
> > Signed-off-by: Anand Moon <linux.amoon@gmail.com>
> > ---
> >
> > Following Neil's suggestion, I have prepared this patch.
> > https://patchwork.kernel.org/patch/11177441/#22964889
> > ---
> > drivers/clk/meson/g12a.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/clk/meson/g12a.c b/drivers/clk/meson/g12a.c
> > index d2760a021301..accae3695fe5 100644
> > --- a/drivers/clk/meson/g12a.c
> > +++ b/drivers/clk/meson/g12a.c
> > @@ -283,6 +283,7 @@ static struct clk_fixed_factor g12a_fclk_div2_div = {
> > .ops = &clk_fixed_factor_ops,
> > .parent_hws = (const struct clk_hw *[]) { &g12a_fixed_pll.hw },
> > .num_parents = 1,
> > + .flags = CLK_IS_CRITICAL,
>
> This makes no sense for because:
> * This clock cannot gate and none of its parents can either. IOW, the
> output of this clock is never disabled.
> * I cannot guess the relation between fdiv2 and the commit description
>
> > },
> > };
> >
> > @@ -681,7 +682,7 @@ static struct clk_regmap g12b_cpub_clk = {
> > &g12a_sys_pll.hw
> > },
> > .num_parents = 2,
> > - .flags = CLK_SET_RATE_PARENT,
> > + .flags = CLK_SET_RATE_PARENT | CLK_IS_CRITICAL,
>
> Why not. Neil what do you think of this ?
> If nothing is claiming this clock and enabling it then I suppose it
> could make sense.
>
>
> > },
> > };
>
Sorry for the noise, I should not have send this patch in first place.
-Anand
next prev parent reply other threads:[~2020-02-17 8:51 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-16 17:34 [PATCHv1 0/3] Odroid N2 failes to boot using upstream kernel using microSD card Anand Moon
2020-02-16 17:34 ` [PATCHv1 1/3] arm64: dts: meson: Add missing regulator linked to VDDAO_3V3 regulator to FLASH_VDD Anand Moon
2020-02-16 17:34 ` [PATCHv1 2/3] arm64: dts: meson: Add missing regulator linked to VCCV5 regulator to VDDIO_C/TF_IO Anand Moon
2020-02-17 7:49 ` Jerome Brunet
2020-02-16 17:34 ` [PATCHv1 3/3] clk: meson: g12a: set cpu clock divider flags too CLK_IS_CRITICAL Anand Moon
2020-02-17 8:02 ` Jerome Brunet
2020-02-17 8:51 ` Anand Moon [this message]
2020-02-17 13:30 ` Anand Moon
2020-02-20 21:15 ` Martin Blumenstingl
2020-02-23 13:34 ` Anand Moon
2020-02-24 9:31 ` Jerome Brunet
2020-02-24 10:17 ` Anand Moon
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