[PATCH] Revert "cpufreq: mediatek: Refine mtk_cpufreq_voltage_tracking()"

Rafael J. Wysocki rafael at kernel.org
Fri Dec 2 11:46:25 PST 2022


On Fri, Dec 2, 2022 at 1:17 PM Rafael J. Wysocki <rafael at kernel.org> wrote:
>
> On Fri, Dec 2, 2022 at 6:26 AM Viresh Kumar <viresh.kumar at linaro.org> wrote:
> >
> > This reverts commit 6a17b3876bc8303612d7ad59ecf7cbc0db418bcd.
> >
> > This commit caused regression on Banana Pi R64 (MT7622), revert until
> > the problem is identified and fixed properly.
> >
> > Link: https://lore.kernel.org/all/930778a1-5e8b-6df6-3276-42dcdadaf682@systemli.org/
> > Cc: v5.19+ <stable at vger.kernel.org> # v5.19+
> > Reported-by: Nick <vincent at systemli.org>
> > Signed-off-by: Viresh Kumar <viresh.kumar at linaro.org>
>
> Do you want me to push this revert for -rc8?

After all, I've decided to queue it up for 6.2, thanks!

> > ---
> >  drivers/cpufreq/mediatek-cpufreq.c | 147 +++++++++++++++++++----------
> >  1 file changed, 96 insertions(+), 51 deletions(-)
> >
> > diff --git a/drivers/cpufreq/mediatek-cpufreq.c b/drivers/cpufreq/mediatek-cpufreq.c
> > index 7f2680bc9a0f..4466d0c91a6a 100644
> > --- a/drivers/cpufreq/mediatek-cpufreq.c
> > +++ b/drivers/cpufreq/mediatek-cpufreq.c
> > @@ -8,7 +8,6 @@
> >  #include <linux/cpu.h>
> >  #include <linux/cpufreq.h>
> >  #include <linux/cpumask.h>
> > -#include <linux/minmax.h>
> >  #include <linux/module.h>
> >  #include <linux/of.h>
> >  #include <linux/of_platform.h>
> > @@ -16,6 +15,8 @@
> >  #include <linux/pm_opp.h>
> >  #include <linux/regulator/consumer.h>
> >
> > +#define VOLT_TOL               (10000)
> > +
> >  struct mtk_cpufreq_platform_data {
> >         int min_volt_shift;
> >         int max_volt_shift;
> > @@ -55,7 +56,6 @@ struct mtk_cpu_dvfs_info {
> >         unsigned int opp_cpu;
> >         unsigned long current_freq;
> >         const struct mtk_cpufreq_platform_data *soc_data;
> > -       int vtrack_max;
> >         bool ccifreq_bound;
> >  };
> >
> > @@ -82,7 +82,6 @@ static int mtk_cpufreq_voltage_tracking(struct mtk_cpu_dvfs_info *info,
> >         struct regulator *proc_reg = info->proc_reg;
> >         struct regulator *sram_reg = info->sram_reg;
> >         int pre_vproc, pre_vsram, new_vsram, vsram, vproc, ret;
> > -       int retry = info->vtrack_max;
> >
> >         pre_vproc = regulator_get_voltage(proc_reg);
> >         if (pre_vproc < 0) {
> > @@ -90,44 +89,91 @@ static int mtk_cpufreq_voltage_tracking(struct mtk_cpu_dvfs_info *info,
> >                         "invalid Vproc value: %d\n", pre_vproc);
> >                 return pre_vproc;
> >         }
> > +       /* Vsram should not exceed the maximum allowed voltage of SoC. */
> > +       new_vsram = min(new_vproc + soc_data->min_volt_shift,
> > +                       soc_data->sram_max_volt);
> > +
> > +       if (pre_vproc < new_vproc) {
> > +               /*
> > +                * When scaling up voltages, Vsram and Vproc scale up step
> > +                * by step. At each step, set Vsram to (Vproc + 200mV) first,
> > +                * then set Vproc to (Vsram - 100mV).
> > +                * Keep doing it until Vsram and Vproc hit target voltages.
> > +                */
> > +               do {
> > +                       pre_vsram = regulator_get_voltage(sram_reg);
> > +                       if (pre_vsram < 0) {
> > +                               dev_err(info->cpu_dev,
> > +                                       "invalid Vsram value: %d\n", pre_vsram);
> > +                               return pre_vsram;
> > +                       }
> > +                       pre_vproc = regulator_get_voltage(proc_reg);
> > +                       if (pre_vproc < 0) {
> > +                               dev_err(info->cpu_dev,
> > +                                       "invalid Vproc value: %d\n", pre_vproc);
> > +                               return pre_vproc;
> > +                       }
> >
> > -       pre_vsram = regulator_get_voltage(sram_reg);
> > -       if (pre_vsram < 0) {
> > -               dev_err(info->cpu_dev, "invalid Vsram value: %d\n", pre_vsram);
> > -               return pre_vsram;
> > -       }
> > +                       vsram = min(new_vsram,
> > +                                   pre_vproc + soc_data->min_volt_shift);
> >
> > -       new_vsram = clamp(new_vproc + soc_data->min_volt_shift,
> > -                         soc_data->sram_min_volt, soc_data->sram_max_volt);
> > +                       if (vsram + VOLT_TOL >= soc_data->sram_max_volt) {
> > +                               vsram = soc_data->sram_max_volt;
> >
> > -       do {
> > -               if (pre_vproc <= new_vproc) {
> > -                       vsram = clamp(pre_vproc + soc_data->max_volt_shift,
> > -                                     soc_data->sram_min_volt, new_vsram);
> > -                       ret = regulator_set_voltage(sram_reg, vsram,
> > -                                                   soc_data->sram_max_volt);
> > +                               /*
> > +                                * If the target Vsram hits the maximum voltage,
> > +                                * try to set the exact voltage value first.
> > +                                */
> > +                               ret = regulator_set_voltage(sram_reg, vsram,
> > +                                                           vsram);
> > +                               if (ret)
> > +                                       ret = regulator_set_voltage(sram_reg,
> > +                                                       vsram - VOLT_TOL,
> > +                                                       vsram);
> >
> > -                       if (ret)
> > -                               return ret;
> > -
> > -                       if (vsram == soc_data->sram_max_volt ||
> > -                           new_vsram == soc_data->sram_min_volt)
> >                                 vproc = new_vproc;
> > -                       else
> > +                       } else {
> > +                               ret = regulator_set_voltage(sram_reg, vsram,
> > +                                                           vsram + VOLT_TOL);
> > +
> >                                 vproc = vsram - soc_data->min_volt_shift;
> > +                       }
> > +                       if (ret)
> > +                               return ret;
> >
> >                         ret = regulator_set_voltage(proc_reg, vproc,
> > -                                                   soc_data->proc_max_volt);
> > +                                                   vproc + VOLT_TOL);
> >                         if (ret) {
> >                                 regulator_set_voltage(sram_reg, pre_vsram,
> > -                                                     soc_data->sram_max_volt);
> > +                                                     pre_vsram);
> >                                 return ret;
> >                         }
> > -               } else if (pre_vproc > new_vproc) {
> > +               } while (vproc < new_vproc || vsram < new_vsram);
> > +       } else if (pre_vproc > new_vproc) {
> > +               /*
> > +                * When scaling down voltages, Vsram and Vproc scale down step
> > +                * by step. At each step, set Vproc to (Vsram - 200mV) first,
> > +                * then set Vproc to (Vproc + 100mV).
> > +                * Keep doing it until Vsram and Vproc hit target voltages.
> > +                */
> > +               do {
> > +                       pre_vproc = regulator_get_voltage(proc_reg);
> > +                       if (pre_vproc < 0) {
> > +                               dev_err(info->cpu_dev,
> > +                                       "invalid Vproc value: %d\n", pre_vproc);
> > +                               return pre_vproc;
> > +                       }
> > +                       pre_vsram = regulator_get_voltage(sram_reg);
> > +                       if (pre_vsram < 0) {
> > +                               dev_err(info->cpu_dev,
> > +                                       "invalid Vsram value: %d\n", pre_vsram);
> > +                               return pre_vsram;
> > +                       }
> > +
> >                         vproc = max(new_vproc,
> >                                     pre_vsram - soc_data->max_volt_shift);
> >                         ret = regulator_set_voltage(proc_reg, vproc,
> > -                                                   soc_data->proc_max_volt);
> > +                                                   vproc + VOLT_TOL);
> >                         if (ret)
> >                                 return ret;
> >
> > @@ -137,24 +183,32 @@ static int mtk_cpufreq_voltage_tracking(struct mtk_cpu_dvfs_info *info,
> >                                 vsram = max(new_vsram,
> >                                             vproc + soc_data->min_volt_shift);
> >
> > -                       ret = regulator_set_voltage(sram_reg, vsram,
> > -                                                   soc_data->sram_max_volt);
> > +                       if (vsram + VOLT_TOL >= soc_data->sram_max_volt) {
> > +                               vsram = soc_data->sram_max_volt;
> > +
> > +                               /*
> > +                                * If the target Vsram hits the maximum voltage,
> > +                                * try to set the exact voltage value first.
> > +                                */
> > +                               ret = regulator_set_voltage(sram_reg, vsram,
> > +                                                           vsram);
> > +                               if (ret)
> > +                                       ret = regulator_set_voltage(sram_reg,
> > +                                                       vsram - VOLT_TOL,
> > +                                                       vsram);
> > +                       } else {
> > +                               ret = regulator_set_voltage(sram_reg, vsram,
> > +                                                           vsram + VOLT_TOL);
> > +                       }
> > +
> >                         if (ret) {
> >                                 regulator_set_voltage(proc_reg, pre_vproc,
> > -                                                     soc_data->proc_max_volt);
> > +                                                     pre_vproc);
> >                                 return ret;
> >                         }
> > -               }
> > -
> > -               pre_vproc = vproc;
> > -               pre_vsram = vsram;
> > -
> > -               if (--retry < 0) {
> > -                       dev_err(info->cpu_dev,
> > -                               "over loop count, failed to set voltage\n");
> > -                       return -EINVAL;
> > -               }
> > -       } while (vproc != new_vproc || vsram != new_vsram);
> > +               } while (vproc > new_vproc + VOLT_TOL ||
> > +                        vsram > new_vsram + VOLT_TOL);
> > +       }
> >
> >         return 0;
> >  }
> > @@ -250,8 +304,8 @@ static int mtk_cpufreq_set_target(struct cpufreq_policy *policy,
> >          * If the new voltage or the intermediate voltage is higher than the
> >          * current voltage, scale up voltage first.
> >          */
> > -       target_vproc = max(inter_vproc, vproc);
> > -       if (pre_vproc <= target_vproc) {
> > +       target_vproc = (inter_vproc > vproc) ? inter_vproc : vproc;
> > +       if (pre_vproc < target_vproc) {
> >                 ret = mtk_cpufreq_set_voltage(info, target_vproc);
> >                 if (ret) {
> >                         dev_err(cpu_dev,
> > @@ -513,15 +567,6 @@ static int mtk_cpu_dvfs_info_init(struct mtk_cpu_dvfs_info *info, int cpu)
> >          */
> >         info->need_voltage_tracking = (info->sram_reg != NULL);
> >
> > -       /*
> > -        * We assume min voltage is 0 and tracking target voltage using
> > -        * min_volt_shift for each iteration.
> > -        * The vtrack_max is 3 times of expeted iteration count.
> > -        */
> > -       info->vtrack_max = 3 * DIV_ROUND_UP(max(info->soc_data->sram_max_volt,
> > -                                               info->soc_data->proc_max_volt),
> > -                                           info->soc_data->min_volt_shift);
> > -
> >         return 0;
> >
> >  out_disable_inter_clock:
> > --



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