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Date: Fri, 2 Dec 2022 13:17:56 +0100
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Viresh Kumar <viresh.kumar@...aro.org>
Cc: "Rafael J. Wysocki" <rafael@...nel.org>,
Matthias Brugger <matthias.bgg@...il.com>,
linux-pm@...r.kernel.org,
Vincent Guittot <vincent.guittot@...aro.org>,
regressions@...mhuis.info, daniel@...rotopia.org,
thomas.huehn@...nordhausen.de, "v5 . 19+" <stable@...r.kernel.org>,
Nick <vincent@...temli.org>, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org,
linux-mediatek@...ts.infradead.org
Subject: Re: [PATCH] Revert "cpufreq: mediatek: Refine mtk_cpufreq_voltage_tracking()"
On Fri, Dec 2, 2022 at 6:26 AM Viresh Kumar <viresh.kumar@...aro.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@...r.kernel.org> # v5.19+
> Reported-by: Nick <vincent@...temli.org>
> Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
Do you want me to push this revert for -rc8?
> ---
> 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:
> --
> 2.31.1.272.g89b43f80a514
>
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