[PATCH v5 4/9] cpufreq: mediatek: Refine mtk_cpufreq_voltage_tracking()
Rex-BC Chen
rex-bc.chen at mediatek.com
Wed May 4 06:05:35 PDT 2022
From: Jia-Wei Chang <jia-wei.chang at mediatek.com>
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 <jia-wei.chang at mediatek.com>
Signed-off-by: Rex-BC Chen <rex-bc.chen at mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno at collabora.com>
---
drivers/cpufreq/mediatek-cpufreq.c | 147 ++++++++++-------------------
1 file changed, 51 insertions(+), 96 deletions(-)
diff --git a/drivers/cpufreq/mediatek-cpufreq.c b/drivers/cpufreq/mediatek-cpufreq.c
index 80a3d4cd49ed..c9f09ddd4428 100644
--- a/drivers/cpufreq/mediatek-cpufreq.c
+++ b/drivers/cpufreq/mediatek-cpufreq.c
@@ -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;
@@ -53,6 +52,7 @@ struct mtk_cpu_dvfs_info {
unsigned int opp_cpu;
unsigned long opp_freq;
const struct mtk_cpufreq_platform_data *soc_data;
+ int vtrack_max;
};
static struct platform_device *cpufreq_pdev;
@@ -78,6 +78,7 @@ 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) {
@@ -85,91 +86,44 @@ 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);
- 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);
- if (vsram + VOLT_TOL >= soc_data->sram_max_volt) {
- vsram = soc_data->sram_max_volt;
+ 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 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);
+ new_vsram = clamp(new_vproc + soc_data->min_volt_shift,
+ soc_data->sram_min_volt, soc_data->sram_max_volt);
- vproc = new_vproc;
- } else {
- ret = regulator_set_voltage(sram_reg, vsram,
- vsram + VOLT_TOL);
+ 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);
- vproc = vsram - soc_data->min_volt_shift;
- }
if (ret)
return ret;
+ if (vsram == soc_data->sram_max_volt ||
+ new_vsram == soc_data->sram_min_volt)
+ vproc = new_vproc;
+ else
+ vproc = vsram - soc_data->min_volt_shift;
+
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;
@@ -179,32 +133,24 @@ 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);
- }
-
+ 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;
}
@@ -268,8 +214,8 @@ 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,
@@ -490,6 +436,15 @@ 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:
--
2.18.0
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