Commit 6a17b387 authored by Jia-Wei Chang's avatar Jia-Wei Chang Committed by Viresh Kumar
Browse files

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: default avatarJia-Wei Chang <jia-wei.chang@mediatek.com>
Signed-off-by: default avatarRex-BC Chen <rex-bc.chen@mediatek.com>
Reviewed-by: default avatarAngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
parent ead858bd

drivers/cpufreq/mediatek-cpufreq.c

+51 −96
Original line number Diff line number Diff line
@@ -8,6 +8,7 @@ 
#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>
@@ -15,8 +16,6 @@ 
#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;
@@ -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 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) {
@@ -80,91 +81,44 @@ 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);

		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);

	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;



				/*

				 * If the target Vsram hits the maximum voltage,

				 * try to set the exact voltage value first.

				 */

	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,

							    vsram);

						    soc_data->sram_max_volt);



			if (ret)

					ret = regulator_set_voltage(sram_reg,

							vsram - VOLT_TOL,

							vsram);

				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;

			}



			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;
@@ -174,33 +128,25 @@ static int mtk_cpufreq_voltage_tracking(struct mtk_cpu_dvfs_info *info, 
				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);

			}



						    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 cpufreq_policy *policy, 
	 * 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 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: