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From: Vasily Khoruzhick <anarsoul@gmail.com>
To: Frank Lee <tiny.windzz@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
	devicetree <devicetree@vger.kernel.org>,
	Linux PM <linux-pm@vger.kernel.org>,
	Maxime Ripard <maxime.ripard@bootlin.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Daniel Lezcano <daniel.lezcano@linaro.org>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	Eduardo Valentin <edubezval@gmail.com>,
	Chen-Yu Tsai <wens@csie.org>, Rob Herring <robh+dt@kernel.org>,
	Jonathan.Cameron@huawei.com,
	Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
	rui.zhang@intel.com, "David S. Miller" <davem@davemloft.net>,
	arm-linux <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v5 08/18] thermal: sun8i: support mod clocks
Date: Sun, 20 Oct 2019 20:41:48 -0700
Message-ID: <CA+E=qVchu9=Qjp9k3QxQ-Dd1oKnfTKQan7AZfbA5k3qk-1N+6A@mail.gmail.com> (raw)
In-Reply-To: <CAEExFWueWPOvXoE+zj67DuKWeamcLgawfOxanfPp6Jyo9Envzg@mail.gmail.com>

On Sun, Aug 25, 2019 at 9:14 AM Frank Lee <tiny.windzz@gmail.com> wrote:
>
> HI Vasily,

Hi Yangtao,

Sorry for the late reply,

> On Wed, Aug 14, 2019 at 11:01 AM Vasily Khoruzhick <anarsoul@gmail.com> wrote:
> >
> > On Tue, Aug 13, 2019 at 1:06 PM Ondřej Jirman <megous@megous.com> wrote:
> > >
> > > On Mon, Aug 12, 2019 at 04:54:15PM -0700, Vasily Khoruzhick wrote:
> > > > On Mon, Aug 12, 2019 at 4:46 PM Frank Lee <tiny.windzz@gmail.com> wrote:
> > > > >
> > > > > HI Vasily,
> > > > >
> > > > > On Sat, Aug 10, 2019 at 2:17 PM Vasily Khoruzhick <anarsoul@gmail.com> wrote:
> > > > > >
> > > > > > On Fri, Aug 9, 2019 at 10:31 PM Yangtao Li <tiny.windzz@gmail.com> wrote:
> > > > > > >
> > > > > > > H3 has extra clock, so introduce something in ths_thermal_chip/ths_device
> > > > > > > and adds the process of the clock.
> > > > > > >
> > > > > > > This is pre-work for supprt it.
> > > > > > >
> > > > > > > Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
> > > > > > > ---
> > > > > > >  drivers/thermal/sun8i_thermal.c | 17 ++++++++++++++++-
> > > > > > >  1 file changed, 16 insertions(+), 1 deletion(-)
> > > > > > >
> > > > > > > diff --git a/drivers/thermal/sun8i_thermal.c b/drivers/thermal/sun8i_thermal.c
> > > > > > > index b934bc81eba7..6f4294c2aba7 100644
> > > > > > > --- a/drivers/thermal/sun8i_thermal.c
> > > > > > > +++ b/drivers/thermal/sun8i_thermal.c
> > > > > > > @@ -54,6 +54,7 @@ struct tsensor {
> > > > > > >  };
> > > > > > >
> > > > > > >  struct ths_thermal_chip {
> > > > > > > +       bool            has_mod_clk;
> > > > > > >         int             sensor_num;
> > > > > > >         int             offset;
> > > > > > >         int             scale;
> > > > > > > @@ -69,6 +70,7 @@ struct ths_device {
> > > > > > >         struct regmap                           *regmap;
> > > > > > >         struct reset_control                    *reset;
> > > > > > >         struct clk                              *bus_clk;
> > > > > > > +       struct clk                              *mod_clk;
> > > > > > >         struct tsensor                          sensor[MAX_SENSOR_NUM];
> > > > > > >  };
> > > > > > >
> > > > > > > @@ -274,6 +276,12 @@ static int sun8i_ths_resource_init(struct ths_device *tmdev)
> > > > > > >         if (IS_ERR(tmdev->bus_clk))
> > > > > > >                 return PTR_ERR(tmdev->bus_clk);
> > > > > > >
> > > > > > > +       if (tmdev->chip->has_mod_clk) {
> > > > > > > +               tmdev->mod_clk = devm_clk_get(&pdev->dev, "mod");
> > > > > > > +               if (IS_ERR(tmdev->mod_clk))
> > > > > > > +                       return PTR_ERR(tmdev->mod_clk);
> > > > > > > +       }
> > > > > > > +
> > > > > > >         ret = reset_control_deassert(tmdev->reset);
> > > > > > >         if (ret)
> > > > > > >                 return ret;
> > > > > > > @@ -282,12 +290,18 @@ static int sun8i_ths_resource_init(struct ths_device *tmdev)
> > > > > > >         if (ret)
> > > > > > >                 goto assert_reset;
> > > > > > >
> > > > > > > -       ret = sun50i_ths_calibrate(tmdev);
> > > > > > > +       ret = clk_prepare_enable(tmdev->mod_clk);
> > > > > >
> > > > > > You have to set rate of modclk before enabling it since you can't rely
> > > > > > on whatever bootloader left for you.
> > > > > >
> > > > > > Also I found that parameters you're using for PC_TEMP_PERIOD, ACQ0 and
> > > > > > ACQ1 are too aggressive and may result in high interrupt rate to the
> > > > > > point when it may stall RCU. I changed driver a bit to use params from
> > > > > > Philipp Rossak's work (modclk set to 4MHz, PC_TEMP_PERIOD is 7, ACQ0
> > > > > > is 255, ACQ1 is 63) and it fixed RCU stalls for me, see [1] for
> > > > > > details.
> > > > >
> > > > > Why is the RCU stall happening, is it caused by a deadlock?
> > > > > Can you provide log information and your configuration?
> > > > > I am a bit curious.
> > > >
> > > > It's not deadlock, I believe it just can't handle that many interrupts
> > > > when running at lowest CPU frequency. Even with Philipp's settings
> > > > there's ~20 interrupts a second from ths. I don't remember how many
> > > > interrupts were there with your settings.
> > > >
> > > > Unfortunately there's nothing interesting in backtraces, I'm using
> > > > Pine64-LTS board.
> > >
> > > Recently there was a similar issue, with buggy CCU driver that caused
> > > CIR interrupts being fired constantly, and it also resulted in RCU
> > > stalls. Looks like a comon cause of RCU stalls.
> > >
> > > THS timing settings probably need to be made specific to the SoC, because
> > > I noticed that the same settings lead to wildly different timings on
> > > different SoCs.
> > >
> > > It would be good to measure how often ths interrupt fires with this driver
> > > on various SoCs.
> > >
> > > 20 times a second and more sounds like overkill. I'd expect a useful
> > > range to be at most 5-10 times a second. That should be enough to stop
> > > overheating the SoC due to suddenly increased load, even without a
> > > heatsink.
> >
> > Note that A64 has 3 sensors and each sensor has individual interrupt,
> > so technically it's 6-7 interrupts per sensor per second
>
> You only need to increase the value of the period to reduce the number
> of interrupts.
> Can you test the relationship between the period and the number of interrupts
> when the mod clock does not change and stays 24M?

I played a bit with your settings and 24M,

with PERIOD = 57 I get 26 interrupts / second
with 87 - 18 interrupts / second
with 116 - 12-15 interrupts / second.

I think we should use 116 for A64 since with it we get reasonable
number of ths interrupts in a second.

Regards,
Vasily

> Thx.
> Yangtao
>
> >
> > > regards,
> > >         o.
> > >
> > > > > Thx,
> > > > > Yangtao
> > > > >
> > > > > >
> > > > > > [1] https://github.com/anarsoul/linux-2.6/commit/46b8bb0fe2ccd1cd88fa9181a2ecbf79e8d513b2
> > > > > >
> > > > > >
> > > > > > >         if (ret)
> > > > > > >                 goto bus_disable;
> > > > > > >
> > > > > > > +       ret = sun50i_ths_calibrate(tmdev);
> > > > > > > +       if (ret)
> > > > > > > +               goto mod_disable;
> > > > > > > +
> > > > > > >         return 0;
> > > > > > >
> > > > > > > +mod_disable:
> > > > > > > +       clk_disable_unprepare(tmdev->mod_clk);
> > > > > > >  bus_disable:
> > > > > > >         clk_disable_unprepare(tmdev->bus_clk);
> > > > > > >  assert_reset:
> > > > > > > @@ -395,6 +409,7 @@ static int sun8i_ths_remove(struct platform_device *pdev)
> > > > > > >  {
> > > > > > >         struct ths_device *tmdev = platform_get_drvdata(pdev);
> > > > > > >
> > > > > > > +       clk_disable_unprepare(tmdev->mod_clk);
> > > > > > >         clk_disable_unprepare(tmdev->bus_clk);
> > > > > > >         reset_control_assert(tmdev->reset);
> > > > > > >
> > > > > > > --
> > > > > > > 2.17.1
> > > > > > >
> > > > > > >
> > > > > > > _______________________________________________
> > > > > > > linux-arm-kernel mailing list
> > > > > > > linux-arm-kernel@lists.infradead.org
> > > > > > > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> > > >
> > > > _______________________________________________
> > > > linux-arm-kernel mailing list
> > > > linux-arm-kernel@lists.infradead.org
> > > > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply index

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-10  5:28 [PATCH v5 00/18] add thermal driver for h6 Yangtao Li
2019-08-10  5:28 ` [PATCH v5 01/18] thermal: sun8i: " Yangtao Li
2019-09-01  2:06   ` Ondřej Jirman
2019-09-01 21:04   ` Ondřej Jirman
2019-08-10  5:28 ` [PATCH v5 02/18] dt-bindings: thermal: add binding document for h6 thermal controller Yangtao Li
2019-08-12  8:56   ` Maxime Ripard
2019-08-12 23:40     ` Frank Lee
2019-08-16  9:47       ` Maxime Ripard
2019-08-10  5:28 ` [PATCH v5 03/18] thermal: fix indentation in makefile Yangtao Li
2019-08-28 12:40   ` Zhang Rui
2019-08-10  5:28 ` [PATCH v5 04/18] thermal: sun8i: get ths sensor number from device compatible Yangtao Li
2019-08-10  5:28 ` [PATCH v5 05/18] thermal: sun8i: rework for sun8i_ths_get_temp() Yangtao Li
2019-08-10  5:28 ` [PATCH v5 06/18] thermal: sun8i: get ths init func from device compatible Yangtao Li
2019-08-10  5:28 ` [PATCH v5 07/18] thermal: sun8i: rework for ths irq handler func Yangtao Li
2019-08-10  5:28 ` [PATCH v5 08/18] thermal: sun8i: support mod clocks Yangtao Li
2019-08-10  6:16   ` Vasily Khoruzhick
2019-08-12 23:46     ` Frank Lee
2019-08-12 23:54       ` Vasily Khoruzhick
2019-08-13 20:06         ` Ondřej Jirman
2019-08-14  3:01           ` Vasily Khoruzhick
2019-08-25 16:14             ` Frank Lee
2019-10-21  3:41               ` Vasily Khoruzhick [this message]
2019-08-10  5:28 ` [PATCH v5 09/18] thermal: sun8i: rework for ths calibrate func Yangtao Li
2019-08-28 12:45   ` Zhang Rui
2019-08-10  5:28 ` [PATCH v5 10/18] dt-bindings: thermal: add binding document for h3 thermal controller Yangtao Li
2019-08-27 15:26   ` Rob Herring
2019-08-10  5:28 ` [PATCH v5 11/18] thermal: sun8i: add thermal driver for h3 Yangtao Li
2019-08-10  5:28 ` [PATCH v5 12/18] dt-bindings: thermal: add binding document for a64 thermal controller Yangtao Li
2019-08-27 15:26   ` Rob Herring
2019-08-10  5:28 ` [PATCH v5 13/18] thermal: sun8i: add thermal driver for A64 Yangtao Li
2019-08-10  5:28 ` [PATCH v5 14/18] dt-bindings: thermal: add binding document for h5 thermal controller Yangtao Li
2019-08-27 15:27   ` Rob Herring
2019-08-10  5:28 ` [PATCH v5 15/18] thermal: sun8i: allow to use custom temperature calculation function Yangtao Li
2019-08-12  8:49   ` Maxime Ripard
2019-08-10  5:28 ` [PATCH v5 16/18] thermal: sun8i: add support for Allwinner H5 thermal sensor Yangtao Li
2019-08-10  5:28 ` [PATCH v5 17/18] dt-bindings: thermal: add binding document for r40 thermal controller Yangtao Li
2019-08-27 15:27   ` Rob Herring
2019-08-10  5:28 ` [PATCH v5 18/18] thermal: sun8i: add support for Allwinner R40 thermal sensor Yangtao Li
2019-08-11 21:14 ` [PATCH v5 00/18] add thermal driver for h6 Clément Péron
2019-08-12 23:36   ` Frank Lee
2019-09-01 21:52 ` Ondřej Jirman
2019-09-02  7:27   ` Maxime Ripard
2019-09-02 10:58     ` Ondřej Jirman

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