From 944b041c91f1e1cd762c39c1222f078550149486 Mon Sep 17 00:00:00 2001 From: Jia-Wei Chang Date: Thu, 5 May 2022 19:52:20 +0800 Subject: [PATCH 10/21] cpufreq: mediatek: Refine mtk_cpufreq_voltage_tracking() Because the difference of sram and proc should in a range of min_volt_shift and max_volt_shift. We need to adjust the sram and proc step by step. We replace VOLT_TOL (voltage tolerance) with the platform data and update the logic to determine the voltage boundary and invoking regulator_set_voltage. - Use 'sram_min_volt' and 'sram_max_volt' to determine the voltage boundary of sram regulator. - Use (sram_min_volt - min_volt_shift) and 'proc_max_volt' to determine the voltage boundary of vproc regulator. Moreover, to prevent infinite loop when tracking voltage, we calculate the maximum value for each platform data. We assume min voltage is 0 and tracking target voltage using min_volt_shift for each iteration. The retry_max is 3 times of expeted iteration count. Signed-off-by: Jia-Wei Chang Signed-off-by: Rex-BC Chen Reviewed-by: AngeloGioacchino Del Regno Signed-off-by: Viresh Kumar --- drivers/cpufreq/mediatek-cpufreq.c | 147 ++++++++++------------------- 1 file changed, 51 insertions(+), 96 deletions(-) --- a/drivers/cpufreq/mediatek-cpufreq.c +++ b/drivers/cpufreq/mediatek-cpufreq.c @@ -8,6 +8,7 @@ #include #include #include +#include #include #include #include @@ -15,8 +16,6 @@ #include #include -#define VOLT_TOL (10000) - struct mtk_cpufreq_platform_data { int min_volt_shift; int max_volt_shift; @@ -48,6 +47,7 @@ struct mtk_cpu_dvfs_info { bool need_voltage_tracking; int pre_vproc; const struct mtk_cpufreq_platform_data *soc_data; + int vtrack_max; }; static struct platform_device *cpufreq_pdev; @@ -73,6 +73,7 @@ static int mtk_cpufreq_voltage_tracking( 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) { @@ -80,91 +81,44 @@ static int mtk_cpufreq_voltage_tracking( "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; - } - vsram = min(new_vsram, - pre_vproc + soc_data->min_volt_shift); + 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; + } - if (vsram + VOLT_TOL >= soc_data->sram_max_volt) { - vsram = soc_data->sram_max_volt; + new_vsram = clamp(new_vproc + soc_data->min_volt_shift, + soc_data->sram_min_volt, 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 { - ret = regulator_set_voltage(sram_reg, vsram, - vsram + VOLT_TOL); - + else vproc = vsram - soc_data->min_volt_shift; - } - if (ret) - return ret; ret = regulator_set_voltage(proc_reg, vproc, - vproc + VOLT_TOL); + soc_data->proc_max_volt); if (ret) { regulator_set_voltage(sram_reg, pre_vsram, - pre_vsram); + soc_data->sram_max_volt); return ret; } - } 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; - } - + } else if (pre_vproc > new_vproc) { vproc = max(new_vproc, pre_vsram - soc_data->max_volt_shift); ret = regulator_set_voltage(proc_reg, vproc, - vproc + VOLT_TOL); + soc_data->proc_max_volt); if (ret) return ret; @@ -174,32 +128,24 @@ static int mtk_cpufreq_voltage_tracking( vsram = max(new_vsram, vproc + soc_data->min_volt_shift); - 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); - } - + ret = regulator_set_voltage(sram_reg, vsram, + soc_data->sram_max_volt); if (ret) { regulator_set_voltage(proc_reg, pre_vproc, - pre_vproc); + soc_data->proc_max_volt); return ret; } - } while (vproc > new_vproc + VOLT_TOL || - vsram > new_vsram + VOLT_TOL); - } + } + + 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); return 0; } @@ -261,8 +207,8 @@ static int mtk_cpufreq_set_target(struct * If the new voltage or the intermediate voltage is higher than the * current voltage, scale up voltage first. */ - target_vproc = (inter_vproc > vproc) ? inter_vproc : vproc; - if (pre_vproc < target_vproc) { + target_vproc = max(inter_vproc, vproc); + if (pre_vproc <= target_vproc) { ret = mtk_cpufreq_set_voltage(info, target_vproc); if (ret) { dev_err(cpu_dev, @@ -417,6 +363,15 @@ static int mtk_cpu_dvfs_info_init(struct */ 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: