linux/drivers/devfreq/mtk-cci-devfreq.c
AngeloGioacchino Del Regno e09bd5757b PM / devfreq: mtk-cci: Handle sram regulator probe deferral
If the regulator_get_optional()	call for the SRAM regulator returns
a probe deferral, we must bail out and retry probing later: failing
to do this will	produce	unstabilities on platforms requiring the
handling for this regulator.

Fixes: b615b00c42da ("PM / devfreq: mediatek: Introduce MediaTek CCI devfreq driver")
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
2022-09-26 03:59:12 +09:00

445 lines
11 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2022 MediaTek Inc.
*/
#include <linux/clk.h>
#include <linux/devfreq.h>
#include <linux/minmax.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/pm_opp.h>
#include <linux/regulator/consumer.h>
struct mtk_ccifreq_platform_data {
int min_volt_shift;
int max_volt_shift;
int proc_max_volt;
int sram_min_volt;
int sram_max_volt;
};
struct mtk_ccifreq_drv {
struct device *dev;
struct devfreq *devfreq;
struct regulator *proc_reg;
struct regulator *sram_reg;
struct clk *cci_clk;
struct clk *inter_clk;
int inter_voltage;
unsigned long pre_freq;
/* Avoid race condition for regulators between notify and policy */
struct mutex reg_lock;
struct notifier_block opp_nb;
const struct mtk_ccifreq_platform_data *soc_data;
int vtrack_max;
};
static int mtk_ccifreq_set_voltage(struct mtk_ccifreq_drv *drv, int new_voltage)
{
const struct mtk_ccifreq_platform_data *soc_data = drv->soc_data;
struct device *dev = drv->dev;
int pre_voltage, pre_vsram, new_vsram, vsram, voltage, ret;
int retry_max = drv->vtrack_max;
if (!drv->sram_reg) {
ret = regulator_set_voltage(drv->proc_reg, new_voltage,
drv->soc_data->proc_max_volt);
return ret;
}
pre_voltage = regulator_get_voltage(drv->proc_reg);
if (pre_voltage < 0) {
dev_err(dev, "invalid vproc value: %d\n", pre_voltage);
return pre_voltage;
}
pre_vsram = regulator_get_voltage(drv->sram_reg);
if (pre_vsram < 0) {
dev_err(dev, "invalid vsram value: %d\n", pre_vsram);
return pre_vsram;
}
new_vsram = clamp(new_voltage + soc_data->min_volt_shift,
soc_data->sram_min_volt, soc_data->sram_max_volt);
do {
if (pre_voltage <= new_voltage) {
vsram = clamp(pre_voltage + soc_data->max_volt_shift,
soc_data->sram_min_volt, new_vsram);
ret = regulator_set_voltage(drv->sram_reg, vsram,
soc_data->sram_max_volt);
if (ret)
return ret;
if (vsram == soc_data->sram_max_volt ||
new_vsram == soc_data->sram_min_volt)
voltage = new_voltage;
else
voltage = vsram - soc_data->min_volt_shift;
ret = regulator_set_voltage(drv->proc_reg, voltage,
soc_data->proc_max_volt);
if (ret) {
regulator_set_voltage(drv->sram_reg, pre_vsram,
soc_data->sram_max_volt);
return ret;
}
} else if (pre_voltage > new_voltage) {
voltage = max(new_voltage,
pre_vsram - soc_data->max_volt_shift);
ret = regulator_set_voltage(drv->proc_reg, voltage,
soc_data->proc_max_volt);
if (ret)
return ret;
if (voltage == new_voltage)
vsram = new_vsram;
else
vsram = max(new_vsram,
voltage + soc_data->min_volt_shift);
ret = regulator_set_voltage(drv->sram_reg, vsram,
soc_data->sram_max_volt);
if (ret) {
regulator_set_voltage(drv->proc_reg, pre_voltage,
soc_data->proc_max_volt);
return ret;
}
}
pre_voltage = voltage;
pre_vsram = vsram;
if (--retry_max < 0) {
dev_err(dev,
"over loop count, failed to set voltage\n");
return -EINVAL;
}
} while (voltage != new_voltage || vsram != new_vsram);
return 0;
}
static int mtk_ccifreq_target(struct device *dev, unsigned long *freq,
u32 flags)
{
struct mtk_ccifreq_drv *drv = dev_get_drvdata(dev);
struct clk *cci_pll = clk_get_parent(drv->cci_clk);
struct dev_pm_opp *opp;
unsigned long opp_rate;
int voltage, pre_voltage, inter_voltage, target_voltage, ret;
if (!drv)
return -EINVAL;
if (drv->pre_freq == *freq)
return 0;
inter_voltage = drv->inter_voltage;
opp_rate = *freq;
opp = devfreq_recommended_opp(dev, &opp_rate, 1);
if (IS_ERR(opp)) {
dev_err(dev, "failed to find opp for freq: %ld\n", opp_rate);
return PTR_ERR(opp);
}
mutex_lock(&drv->reg_lock);
voltage = dev_pm_opp_get_voltage(opp);
dev_pm_opp_put(opp);
pre_voltage = regulator_get_voltage(drv->proc_reg);
if (pre_voltage < 0) {
dev_err(dev, "invalid vproc value: %d\n", pre_voltage);
ret = pre_voltage;
goto out_unlock;
}
/* scale up: set voltage first then freq. */
target_voltage = max(inter_voltage, voltage);
if (pre_voltage <= target_voltage) {
ret = mtk_ccifreq_set_voltage(drv, target_voltage);
if (ret) {
dev_err(dev, "failed to scale up voltage\n");
goto out_restore_voltage;
}
}
/* switch the cci clock to intermediate clock source. */
ret = clk_set_parent(drv->cci_clk, drv->inter_clk);
if (ret) {
dev_err(dev, "failed to re-parent cci clock\n");
goto out_restore_voltage;
}
/* set the original clock to target rate. */
ret = clk_set_rate(cci_pll, *freq);
if (ret) {
dev_err(dev, "failed to set cci pll rate: %d\n", ret);
clk_set_parent(drv->cci_clk, cci_pll);
goto out_restore_voltage;
}
/* switch the cci clock back to the original clock source. */
ret = clk_set_parent(drv->cci_clk, cci_pll);
if (ret) {
dev_err(dev, "failed to re-parent cci clock\n");
mtk_ccifreq_set_voltage(drv, inter_voltage);
goto out_unlock;
}
/*
* If the new voltage is lower than the intermediate voltage or the
* original voltage, scale down to the new voltage.
*/
if (voltage < inter_voltage || voltage < pre_voltage) {
ret = mtk_ccifreq_set_voltage(drv, voltage);
if (ret) {
dev_err(dev, "failed to scale down voltage\n");
goto out_unlock;
}
}
drv->pre_freq = *freq;
mutex_unlock(&drv->reg_lock);
return 0;
out_restore_voltage:
mtk_ccifreq_set_voltage(drv, pre_voltage);
out_unlock:
mutex_unlock(&drv->reg_lock);
return ret;
}
static int mtk_ccifreq_opp_notifier(struct notifier_block *nb,
unsigned long event, void *data)
{
struct dev_pm_opp *opp = data;
struct mtk_ccifreq_drv *drv;
unsigned long freq, volt;
drv = container_of(nb, struct mtk_ccifreq_drv, opp_nb);
if (event == OPP_EVENT_ADJUST_VOLTAGE) {
freq = dev_pm_opp_get_freq(opp);
mutex_lock(&drv->reg_lock);
/* current opp item is changed */
if (freq == drv->pre_freq) {
volt = dev_pm_opp_get_voltage(opp);
mtk_ccifreq_set_voltage(drv, volt);
}
mutex_unlock(&drv->reg_lock);
}
return 0;
}
static struct devfreq_dev_profile mtk_ccifreq_profile = {
.target = mtk_ccifreq_target,
};
static int mtk_ccifreq_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct mtk_ccifreq_drv *drv;
struct devfreq_passive_data *passive_data;
struct dev_pm_opp *opp;
unsigned long rate, opp_volt;
int ret;
drv = devm_kzalloc(dev, sizeof(*drv), GFP_KERNEL);
if (!drv)
return -ENOMEM;
drv->dev = dev;
drv->soc_data = (const struct mtk_ccifreq_platform_data *)
of_device_get_match_data(&pdev->dev);
mutex_init(&drv->reg_lock);
platform_set_drvdata(pdev, drv);
drv->cci_clk = devm_clk_get(dev, "cci");
if (IS_ERR(drv->cci_clk)) {
ret = PTR_ERR(drv->cci_clk);
return dev_err_probe(dev, ret, "failed to get cci clk\n");
}
drv->inter_clk = devm_clk_get(dev, "intermediate");
if (IS_ERR(drv->inter_clk)) {
ret = PTR_ERR(drv->inter_clk);
return dev_err_probe(dev, ret,
"failed to get intermediate clk\n");
}
drv->proc_reg = devm_regulator_get_optional(dev, "proc");
if (IS_ERR(drv->proc_reg)) {
ret = PTR_ERR(drv->proc_reg);
return dev_err_probe(dev, ret,
"failed to get proc regulator\n");
}
ret = regulator_enable(drv->proc_reg);
if (ret) {
dev_err(dev, "failed to enable proc regulator\n");
return ret;
}
drv->sram_reg = devm_regulator_get_optional(dev, "sram");
if (IS_ERR(drv->sram_reg)) {
ret = PTR_ERR(drv->sram_reg);
if (ret == -EPROBE_DEFER)
goto out_free_resources;
drv->sram_reg = NULL;
} else {
ret = regulator_enable(drv->sram_reg);
if (ret) {
dev_err(dev, "failed to enable sram regulator\n");
goto out_free_resources;
}
}
/*
* We assume min voltage is 0 and tracking target voltage using
* min_volt_shift for each iteration.
* The retry_max is 3 times of expected iteration count.
*/
drv->vtrack_max = 3 * DIV_ROUND_UP(max(drv->soc_data->sram_max_volt,
drv->soc_data->proc_max_volt),
drv->soc_data->min_volt_shift);
ret = clk_prepare_enable(drv->cci_clk);
if (ret)
goto out_free_resources;
ret = dev_pm_opp_of_add_table(dev);
if (ret) {
dev_err(dev, "failed to add opp table: %d\n", ret);
goto out_disable_cci_clk;
}
rate = clk_get_rate(drv->inter_clk);
opp = dev_pm_opp_find_freq_ceil(dev, &rate);
if (IS_ERR(opp)) {
ret = PTR_ERR(opp);
dev_err(dev, "failed to get intermediate opp: %d\n", ret);
goto out_remove_opp_table;
}
drv->inter_voltage = dev_pm_opp_get_voltage(opp);
dev_pm_opp_put(opp);
rate = U32_MAX;
opp = dev_pm_opp_find_freq_floor(drv->dev, &rate);
if (IS_ERR(opp)) {
dev_err(dev, "failed to get opp\n");
ret = PTR_ERR(opp);
goto out_remove_opp_table;
}
opp_volt = dev_pm_opp_get_voltage(opp);
dev_pm_opp_put(opp);
ret = mtk_ccifreq_set_voltage(drv, opp_volt);
if (ret) {
dev_err(dev, "failed to scale to highest voltage %lu in proc_reg\n",
opp_volt);
goto out_remove_opp_table;
}
passive_data = devm_kzalloc(dev, sizeof(*passive_data), GFP_KERNEL);
if (!passive_data) {
ret = -ENOMEM;
goto out_remove_opp_table;
}
passive_data->parent_type = CPUFREQ_PARENT_DEV;
drv->devfreq = devm_devfreq_add_device(dev, &mtk_ccifreq_profile,
DEVFREQ_GOV_PASSIVE,
passive_data);
if (IS_ERR(drv->devfreq)) {
ret = -EPROBE_DEFER;
dev_err(dev, "failed to add devfreq device: %ld\n",
PTR_ERR(drv->devfreq));
goto out_remove_opp_table;
}
drv->opp_nb.notifier_call = mtk_ccifreq_opp_notifier;
ret = dev_pm_opp_register_notifier(dev, &drv->opp_nb);
if (ret) {
dev_err(dev, "failed to register opp notifier: %d\n", ret);
goto out_remove_opp_table;
}
return 0;
out_remove_opp_table:
dev_pm_opp_of_remove_table(dev);
out_disable_cci_clk:
clk_disable_unprepare(drv->cci_clk);
out_free_resources:
if (regulator_is_enabled(drv->proc_reg))
regulator_disable(drv->proc_reg);
if (drv->sram_reg && regulator_is_enabled(drv->sram_reg))
regulator_disable(drv->sram_reg);
return ret;
}
static int mtk_ccifreq_remove(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct mtk_ccifreq_drv *drv;
drv = platform_get_drvdata(pdev);
dev_pm_opp_unregister_notifier(dev, &drv->opp_nb);
dev_pm_opp_of_remove_table(dev);
clk_disable_unprepare(drv->cci_clk);
regulator_disable(drv->proc_reg);
if (drv->sram_reg)
regulator_disable(drv->sram_reg);
return 0;
}
static const struct mtk_ccifreq_platform_data mt8183_platform_data = {
.min_volt_shift = 100000,
.max_volt_shift = 200000,
.proc_max_volt = 1150000,
};
static const struct mtk_ccifreq_platform_data mt8186_platform_data = {
.min_volt_shift = 100000,
.max_volt_shift = 250000,
.proc_max_volt = 1118750,
.sram_min_volt = 850000,
.sram_max_volt = 1118750,
};
static const struct of_device_id mtk_ccifreq_machines[] = {
{ .compatible = "mediatek,mt8183-cci", .data = &mt8183_platform_data },
{ .compatible = "mediatek,mt8186-cci", .data = &mt8186_platform_data },
{ },
};
MODULE_DEVICE_TABLE(of, mtk_ccifreq_machines);
static struct platform_driver mtk_ccifreq_platdrv = {
.probe = mtk_ccifreq_probe,
.remove = mtk_ccifreq_remove,
.driver = {
.name = "mtk-ccifreq",
.of_match_table = mtk_ccifreq_machines,
},
};
module_platform_driver(mtk_ccifreq_platdrv);
MODULE_DESCRIPTION("MediaTek CCI devfreq driver");
MODULE_AUTHOR("Jia-Wei Chang <jia-wei.chang@mediatek.com>");
MODULE_LICENSE("GPL v2");