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References: <20211019130809.21281-1-o.rempel@pengutronix.de> <20211020050459.GE16320@pengutronix.de>
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From:   Petr Benes <petrben@gmail.com>
Date:   Wed, 20 Oct 2021 17:53:03 +0200
Message-ID: <CAPwXO5b=z1nhQCo55A_XuK-Es2o7TrL2Vj6AkRSXa3Wxh0s8sA@mail.gmail.com>
Subject: Re: [PATCH v2] thermal: imx: implement runtime PM support
To:     Oleksij Rempel <o.rempel@pengutronix.de>
Cc:     Shawn Guo <shawnguo@kernel.org>,
        Sascha Hauer <s.hauer@pengutronix.de>,
        Amit Kucheria <amitk@kernel.org>,
        Andrzej Pietrasiewicz <andrzej.p@collabora.com>,
        Daniel Lezcano <daniel.lezcano@linaro.org>,
        Fabio Estevam <festevam@gmail.com>,
        NXP Linux Team <linux-imx@nxp.com>,
        Pengutronix Kernel Team <kernel@pengutronix.de>,
        Zhang Rui <rui.zhang@intel.com>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-pm@vger.kernel.org, David Jander <david@protonic.nl>,
        =?UTF-8?B?TWljaGFsIFZva8OhxI0=?= <michal.vokac@ysoft.com>
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On Wed, 20 Oct 2021 at 07:05, Oleksij Rempel <o.rempel@pengutronix.de> wrote:
>
> Hi Petr and Michal,
>
> I forgot to add you for v2 in CC. Please test/review this version.

Hi Oleksij,

It works good. with PM as well as without PM. The only minor issue I found is,
that the first temperature reading (when the driver probes) fails. That is
(val & soc_data->temp_valid_mask) == 0) holds true. How does
pm_runtime_resume_and_get() behave in imx_thermal_probe()?
Does it go through imx_thermal_runtime_resume() with usleep_range()?

>
> On Tue, Oct 19, 2021 at 03:08:09PM +0200, Oleksij Rempel wrote:
> > Starting with commit d92ed2c9d3ff ("thermal: imx: Use driver's local
> > data to decide whether to run a measurement") this driver stared using
> > irq_enabled flag to make decision to power on/off the thermal core. This
> > triggered a regression, where after reaching critical temperature, alarm
> > IRQ handler set irq_enabled to false,  disabled thermal core and was not
> > able read temperature and disable cooling sequence.
> >
> > In case the cooling device is "CPU/GPU freq", the system will run with
> > reduce performance until next reboot.
> >
> > To solve this issue, we need to move all parts implementing hand made
> > runtime power management and let it handle actual runtime PM framework.
> >
> > Fixes: d92ed2c9d3ff ("thermal: imx: Use driver's local data to decide whether to run a measurement")
> > Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
> > ---
> >  drivers/thermal/imx_thermal.c | 143 +++++++++++++++++++++-------------
> >  1 file changed, 89 insertions(+), 54 deletions(-)
> >
> > diff --git a/drivers/thermal/imx_thermal.c b/drivers/thermal/imx_thermal.c
> > index 2c7473d86a59..cb5a4354fc75 100644
> > --- a/drivers/thermal/imx_thermal.c
> > +++ b/drivers/thermal/imx_thermal.c
> > @@ -15,6 +15,7 @@
> >  #include <linux/regmap.h>
> >  #include <linux/thermal.h>
> >  #include <linux/nvmem-consumer.h>
> > +#include <linux/pm_runtime.h>
> >
> >  #define REG_SET              0x4
> >  #define REG_CLR              0x8
> > @@ -194,6 +195,7 @@ static struct thermal_soc_data thermal_imx7d_data = {
> >  };
> >
> >  struct imx_thermal_data {
> > +     struct device *dev;
> >       struct cpufreq_policy *policy;
> >       struct thermal_zone_device *tz;
> >       struct thermal_cooling_device *cdev;
> > @@ -252,44 +254,15 @@ static int imx_get_temp(struct thermal_zone_device *tz, int *temp)
> >       const struct thermal_soc_data *soc_data = data->socdata;
> >       struct regmap *map = data->tempmon;
> >       unsigned int n_meas;
> > -     bool wait, run_measurement;
> >       u32 val;
> > +     int ret;
> >
> > -     run_measurement = !data->irq_enabled;
> > -     if (!run_measurement) {
> > -             /* Check if a measurement is currently in progress */
> > -             regmap_read(map, soc_data->temp_data, &val);
> > -             wait = !(val & soc_data->temp_valid_mask);
> > -     } else {
> > -             /*
> > -              * Every time we measure the temperature, we will power on the
> > -              * temperature sensor, enable measurements, take a reading,
> > -              * disable measurements, power off the temperature sensor.
> > -              */
> > -             regmap_write(map, soc_data->sensor_ctrl + REG_CLR,
> > -                         soc_data->power_down_mask);
> > -             regmap_write(map, soc_data->sensor_ctrl + REG_SET,
> > -                         soc_data->measure_temp_mask);
> > -
> > -             wait = true;
> > -     }
> > -
> > -     /*
> > -      * According to the temp sensor designers, it may require up to ~17us
> > -      * to complete a measurement.
> > -      */
> > -     if (wait)
> > -             usleep_range(20, 50);
> > +     ret = pm_runtime_resume_and_get(data->dev);
> > +     if (ret < 0)
> > +             return ret;
> >
> >       regmap_read(map, soc_data->temp_data, &val);
> >
> > -     if (run_measurement) {
> > -             regmap_write(map, soc_data->sensor_ctrl + REG_CLR,
> > -                          soc_data->measure_temp_mask);
> > -             regmap_write(map, soc_data->sensor_ctrl + REG_SET,
> > -                          soc_data->power_down_mask);
> > -     }
> > -
> >       if ((val & soc_data->temp_valid_mask) == 0) {
> >               dev_dbg(&tz->device, "temp measurement never finished\n");
> >               return -EAGAIN;
> > @@ -328,6 +301,8 @@ static int imx_get_temp(struct thermal_zone_device *tz, int *temp)
> >               enable_irq(data->irq);
> >       }
> >
> > +     pm_runtime_put(data->dev);
> > +
> >       return 0;
> >  }
> >
> > @@ -335,24 +310,16 @@ static int imx_change_mode(struct thermal_zone_device *tz,
> >                          enum thermal_device_mode mode)
> >  {
> >       struct imx_thermal_data *data = tz->devdata;
> > -     struct regmap *map = data->tempmon;
> > -     const struct thermal_soc_data *soc_data = data->socdata;
> >
> >       if (mode == THERMAL_DEVICE_ENABLED) {
> > -             regmap_write(map, soc_data->sensor_ctrl + REG_CLR,
> > -                          soc_data->power_down_mask);
> > -             regmap_write(map, soc_data->sensor_ctrl + REG_SET,
> > -                          soc_data->measure_temp_mask);
> > +             pm_runtime_get(data->dev);
> >
> >               if (!data->irq_enabled) {
> >                       data->irq_enabled = true;
> >                       enable_irq(data->irq);
> >               }
> >       } else {
> > -             regmap_write(map, soc_data->sensor_ctrl + REG_CLR,
> > -                          soc_data->measure_temp_mask);
> > -             regmap_write(map, soc_data->sensor_ctrl + REG_SET,
> > -                          soc_data->power_down_mask);
> > +             pm_runtime_put(data->dev);
> >
> >               if (data->irq_enabled) {
> >                       disable_irq(data->irq);
> > @@ -393,6 +360,11 @@ static int imx_set_trip_temp(struct thermal_zone_device *tz, int trip,
> >                            int temp)
> >  {
> >       struct imx_thermal_data *data = tz->devdata;
> > +     int ret;
> > +
> > +     ret = pm_runtime_resume_and_get(data->dev);
> > +     if (ret < 0)
> > +             return ret;
> >
> >       /* do not allow changing critical threshold */
> >       if (trip == IMX_TRIP_CRITICAL)
> > @@ -406,6 +378,8 @@ static int imx_set_trip_temp(struct thermal_zone_device *tz, int trip,
> >
> >       imx_set_alarm_temp(data, temp);
> >
> > +     pm_runtime_put(data->dev);
> > +
> >       return 0;
> >  }
> >
> > @@ -681,6 +655,8 @@ static int imx_thermal_probe(struct platform_device *pdev)
> >       if (!data)
> >               return -ENOMEM;
> >
> > +     data->dev = &pdev->dev;
> > +
> >       map = syscon_regmap_lookup_by_phandle(pdev->dev.of_node, "fsl,tempmon");
> >       if (IS_ERR(map)) {
> >               ret = PTR_ERR(map);
> > @@ -801,6 +777,14 @@ static int imx_thermal_probe(struct platform_device *pdev)
> >       regmap_write(map, data->socdata->sensor_ctrl + REG_SET,
> >                    data->socdata->measure_temp_mask);
> >
> > +     /* the core was configured and enabled just before */
> > +     pm_runtime_set_active(&pdev->dev);
> > +     pm_runtime_enable(data->dev);
> > +
> > +     ret = pm_runtime_resume_and_get(data->dev);
> > +     if (ret < 0)
> > +             goto disable_runtime_pm;
> > +
> >       data->irq_enabled = true;
> >       ret = thermal_zone_device_enable(data->tz);
> >       if (ret)
> > @@ -814,10 +798,15 @@ static int imx_thermal_probe(struct platform_device *pdev)
> >               goto thermal_zone_unregister;
> >       }
> >
> > +     pm_runtime_put(data->dev);
> > +
> >       return 0;
> >
> >  thermal_zone_unregister:
> >       thermal_zone_device_unregister(data->tz);
> > +disable_runtime_pm:
> > +     pm_runtime_put_noidle(data->dev);
> > +     pm_runtime_disable(data->dev);
> >  clk_disable:
> >       clk_disable_unprepare(data->thermal_clk);
> >  legacy_cleanup:
> > @@ -829,13 +818,9 @@ static int imx_thermal_probe(struct platform_device *pdev)
> >  static int imx_thermal_remove(struct platform_device *pdev)
> >  {
> >       struct imx_thermal_data *data = platform_get_drvdata(pdev);
> > -     struct regmap *map = data->tempmon;
> >
> > -     /* Disable measurements */
> > -     regmap_write(map, data->socdata->sensor_ctrl + REG_SET,
> > -                  data->socdata->power_down_mask);
> > -     if (!IS_ERR(data->thermal_clk))
> > -             clk_disable_unprepare(data->thermal_clk);
> > +     pm_runtime_put_noidle(data->dev);
> > +     pm_runtime_disable(data->dev);
> >
> >       thermal_zone_device_unregister(data->tz);
> >       imx_thermal_unregister_legacy_cooling(data);
> > @@ -858,29 +843,79 @@ static int __maybe_unused imx_thermal_suspend(struct device *dev)
> >       ret = thermal_zone_device_disable(data->tz);
> >       if (ret)
> >               return ret;
> > +
> > +     return pm_runtime_force_suspend(data->dev);
> > +}
> > +
> > +static int __maybe_unused imx_thermal_resume(struct device *dev)
> > +{
> > +     struct imx_thermal_data *data = dev_get_drvdata(dev);
> > +     int ret;
> > +
> > +     ret = pm_runtime_force_resume(data->dev);
> > +     if (ret)
> > +             return ret;
> > +     /* Enabled thermal sensor after resume */
> > +     return thermal_zone_device_enable(data->tz);
> > +}
> > +
> > +static int __maybe_unused imx_thermal_runtime_suspend(struct device *dev)
> > +{
> > +     struct imx_thermal_data *data = dev_get_drvdata(dev);
> > +     const struct thermal_soc_data *socdata = data->socdata;
> > +     struct regmap *map = data->tempmon;
> > +     int ret;
> > +
> > +     ret = regmap_write(map, socdata->sensor_ctrl + REG_CLR,
> > +                        socdata->measure_temp_mask);
> > +     if (ret)
> > +             return ret;
> > +
> > +     ret = regmap_write(map, socdata->sensor_ctrl + REG_SET,
> > +                        socdata->power_down_mask);
> > +     if (ret)
> > +             return ret;
> > +
> >       clk_disable_unprepare(data->thermal_clk);
> >
> >       return 0;
> >  }
> >
> > -static int __maybe_unused imx_thermal_resume(struct device *dev)
> > +static int __maybe_unused imx_thermal_runtime_resume(struct device *dev)
> >  {
> >       struct imx_thermal_data *data = dev_get_drvdata(dev);
> > +     const struct thermal_soc_data *socdata = data->socdata;
> > +     struct regmap *map = data->tempmon;
> >       int ret;
> >
> >       ret = clk_prepare_enable(data->thermal_clk);
> >       if (ret)
> >               return ret;
> > -     /* Enabled thermal sensor after resume */
> > -     ret = thermal_zone_device_enable(data->tz);
> > +
> > +     ret = regmap_write(map, socdata->sensor_ctrl + REG_CLR,
> > +                        socdata->power_down_mask);
> > +     if (ret)
> > +             return ret;
> > +
> > +     ret = regmap_write(map, socdata->sensor_ctrl + REG_SET,
> > +                        socdata->measure_temp_mask);
> >       if (ret)
> >               return ret;
> >
> > +     /*
> > +      * According to the temp sensor designers, it may require up to ~17us
> > +      * to complete a measurement.
> > +      */
> > +     usleep_range(20, 50);
> > +
> >       return 0;
> >  }
> >
> > -static SIMPLE_DEV_PM_OPS(imx_thermal_pm_ops,
> > -                      imx_thermal_suspend, imx_thermal_resume);
> > +static const struct dev_pm_ops imx_thermal_pm_ops = {
> > +     SET_SYSTEM_SLEEP_PM_OPS(imx_thermal_suspend, imx_thermal_resume)
> > +     SET_RUNTIME_PM_OPS(imx_thermal_runtime_suspend,
> > +                        imx_thermal_runtime_resume, NULL)
> > +};
> >
> >  static struct platform_driver imx_thermal = {
> >       .driver = {
> > --
> > 2.30.2
> >
> >
>
> --
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