[PATCH 3/3] devfreq: add mediatek cci devfreq

Andrew-sh Cheng
2019-01-29T06:35:04Z

From: "Andrew-sh.Cheng" <andrew-sh.cheng-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>

For big/little cpu cluster architecture,
not only CPU frequency, but CCI frequency will also affect performance.

Little cores and cci share the same buck in Mediatek mt8183 IC,
so we add a CCI devfreq which will get notification when buck voltage
is changed, then CCI devfreq can set cci frequency as high as possible.

Signed-off-by: Andrew-sh.Cheng <andrew-sh.cheng-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
---
drivers/devfreq/Kconfig | 9 ++
drivers/devfreq/Makefile | 1 +
drivers/devfreq/mt8183-cci-devfreq.c | 224 +++++++++++++++++++++++++++++++++++
3 files changed, 234 insertions(+)
create mode 100644 drivers/devfreq/mt8183-cci-devfreq.c

diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig
index 6a172d3..0b14aab 100644
--- a/drivers/devfreq/Kconfig
+++ b/drivers/devfreq/Kconfig
@@ -113,6 +113,15 @@ config ARM_RK3399_DMC_DEVFREQ
It sets the frequency for the memory controller and reads the usage counts
from hardware.

+config ARM_MT8183_CCI_DEVFREQ
+ tristate "MT8183 CCI DEVFREQ Driver"
+ depends on ARM_MEDIATEK_CPUFREQ
+ help
+ This adds devfreq for cci clock
+ which is shared the same regulator with cpu cluster.
+ It can track buck voltage and update a proper cci frequency.
+ Use notification to get regulator status.
+
source "drivers/devfreq/event/Kconfig"

endif # PM_DEVFREQ
diff --git a/drivers/devfreq/Makefile b/drivers/devfreq/Makefile
index 32b8d4d..25afe8c 100644
--- a/drivers/devfreq/Makefile
+++ b/drivers/devfreq/Makefile
@@ -11,6 +11,7 @@ obj-$(CONFIG_DEVFREQ_GOV_PASSIVE) += governor_passive.o
obj-$(CONFIG_ARM_EXYNOS_BUS_DEVFREQ) += exynos-bus.o
obj-$(CONFIG_ARM_RK3399_DMC_DEVFREQ) += rk3399_dmc.o
obj-$(CONFIG_ARM_TEGRA_DEVFREQ) += tegra-devfreq.o
+obj-$(CONFIG_ARM_MT8183_CCI_DEVFREQ) += mt8183-cci-devfreq.o

# DEVFREQ Event Drivers
obj-$(CONFIG_PM_DEVFREQ_EVENT) += event/
diff --git a/drivers/devfreq/mt8183-cci-devfreq.c b/drivers/devfreq/mt8183-cci-devfreq.c
new file mode 100644
index 0000000..4837892
--- /dev/null
+++ b/drivers/devfreq/mt8183-cci-devfreq.c
@@ -0,0 +1,224 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Copyright (c) 2018 MediaTek Inc.
+#include <linux/cpu.h>
+#include <linux/cpufreq.h>
+#include <linux/devfreq.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+
+#include "governor.h"
+
+struct cci_devfreq_data {
+ struct devfreq *devfreq;
+ struct regulator *proc_reg;
+ struct clk *cci_clk;
+ unsigned long buck_volt;
+ int volt_increasing;
+ struct notifier_block nb;
+};
+
+static int mtk_cci_governor_get_target(struct devfreq *devfreq,
+ unsigned long *freq)
+{
+ struct cci_devfreq_data *cci_devdata;
+ int i, opp_count;
+ struct dev_pm_opp *opp;
+ unsigned long opp_rate, opp_voltage;
+
+ cci_devdata = dev_get_drvdata(devfreq->dev.parent);
+
+ /* find available frequency */
+ opp_count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
+ for (i = 0, opp_rate = ULONG_MAX; i < opp_count; i++, opp_rate--) {
+ opp = dev_pm_opp_find_freq_floor(devfreq->dev.parent,
+ &opp_rate);
+ opp_voltage = dev_pm_opp_get_voltage(opp);
+ dev_pm_opp_put(opp);
+
+ if (opp_voltage <= cci_devdata->buck_volt)
+ break;
+ }
+ *freq = opp_rate;
+
+ return 0;
+}
+
+static int mtk_cci_governor_event_handler(struct devfreq *devfreq,
+ unsigned int event, void *data)
+{
+ return 0;
+}
+
+static struct devfreq_governor mtk_cci_devfreq_governor = {
+ .name = "voltage_monitor",
+ .get_target_freq = mtk_cci_governor_get_target,
+ .event_handler = mtk_cci_governor_event_handler,
+};
+
+static int mtk_cci_devfreq_target(struct device *dev, unsigned long *freq,
+ u32 flags)
+{
+ struct cci_devfreq_data *cci_devdata;
+
+ cci_devdata = dev_get_drvdata(dev);
+
+ clk_set_rate(cci_devdata->cci_clk, *freq);
+
+ return 0;
+}
+
+static struct devfreq_dev_profile cci_devfreq_profile = {
+ .polling_ms = 0,
+ .target = mtk_cci_devfreq_target,
+};
+
+static int cci_devfreq_regulator_notifier(struct notifier_block *nb,
+ unsigned long val, void *data)
+{
+ struct cci_devfreq_data *cci_devdata =
+ container_of(nb, struct cci_devfreq_data, nb);
+
+ /* deal with reduce frequency */
+ if (val & REGULATOR_EVENT_PRE_VOLTAGE_CHANGE) {
+ struct pre_voltage_change_data *pvc_data = data;
+
+ if (pvc_data->old_uV > pvc_data->min_uV) {
+ cci_devdata->volt_increasing = 0;
+ cci_devdata->buck_volt =
+ (unsigned long)(pvc_data->min_uV);
+ mutex_lock(&cci_devdata->devfreq->lock);
+ update_devfreq(cci_devdata->devfreq);
+ mutex_unlock(&cci_devdata->devfreq->lock);
+ } else {
+ cci_devdata->volt_increasing = 1;
+ }
+ }
+ /* deal with abort reduce frequency */
+ if ((val & REGULATOR_EVENT_ABORT_VOLTAGE_CHANGE) ||
+ /* deal with increase frequency */
+ ((val & REGULATOR_EVENT_VOLTAGE_CHANGE) &&
+ cci_devdata->volt_increasing == 1)) {
+ cci_devdata->buck_volt = (unsigned long)data;
+ mutex_lock(&cci_devdata->devfreq->lock);
+ update_devfreq(cci_devdata->devfreq);
+ mutex_unlock(&cci_devdata->devfreq->lock);
+ }
+
+ return 0;
+}
+
+static int mtk_cci_devfreq_probe(struct platform_device *pdev)
+{
+ struct device *cci_dev = &pdev->dev;
+ struct cci_devfreq_data *cci_devdata;
+ struct notifier_block *nb;
+ int ret;
+
+ dev_pm_opp_of_add_table(&pdev->dev);
+
+ cci_devdata = devm_kzalloc(cci_dev, sizeof(*cci_devdata), GFP_KERNEL);
+ if (!cci_devdata)
+ return -ENOMEM;
+ nb = &cci_devdata->nb;
+ cci_devdata->cci_clk = ERR_PTR(-ENODEV);
+ cci_devdata->proc_reg = ERR_PTR(-ENODEV);
+
+ cci_devdata->cci_clk = clk_get(cci_dev, "cci_clock");
+ ret = PTR_ERR_OR_ZERO(cci_devdata->cci_clk);
+ if (ret) {
+ if (ret == -EPROBE_DEFER)
+ pr_err("cci clock not ready, retry\n");
+ else
+ pr_err("no clock for cci: %d\n", ret);
+
+ goto out_free_resources;
+ }
+
+ cci_devdata->proc_reg = regulator_get_optional(cci_dev, "proc");
+ ret = PTR_ERR_OR_ZERO(cci_devdata->proc_reg);
+ if (ret) {
+ if (ret == -EPROBE_DEFER)
+ pr_err("cci regulator not ready, retry\n");
+ else
+ pr_err("no regulator for cci: %d\n", ret);
+
+ goto out_free_resources;
+ }
+
+ platform_set_drvdata(pdev, cci_devdata);
+
+ /* create cci_devfreq and add to cci device.
+ * governor is voltage_monitor.
+ * governor will get platform_device data to make decision.
+ */
+ cci_devdata->devfreq = devm_devfreq_add_device(cci_dev,
+ &cci_devfreq_profile,
+ "voltage_monitor",
+ NULL);
+
+ nb->notifier_call = cci_devfreq_regulator_notifier;
+ regulator_register_notifier(cci_devdata->proc_reg,
+ nb);
+
+ return 0;
+
+out_free_resources:
+ if (!IS_ERR(cci_devdata->cci_clk))
+ clk_put(cci_devdata->cci_clk);
+ if (!IS_ERR(cci_devdata->proc_reg))
+ regulator_put(cci_devdata->proc_reg);
+
+ return ret;
+}
+
+static const struct of_device_id mediatek_cci_devfreq_of_match[] = {
+ { .compatible = "mediatek,mt8183-cci" },
+ { },
+};
+MODULE_DEVICE_TABLE(of, mediatek_cci_devfreq_of_match);
+
+static struct platform_driver cci_devfreq_driver = {
+ .probe = mtk_cci_devfreq_probe,
+ .driver = {
+ .name = "mediatek-cci-devfreq",
+ .of_match_table = mediatek_cci_devfreq_of_match,
+ },
+};
+
+static int __init mtk_cci_devfreq_init(void)
+{
+ int ret = 0;
+
+ ret = devfreq_add_governor(&mtk_cci_devfreq_governor);
+ if (ret) {
+ pr_err("%s: failed to add governor: %d\n", __func__, ret);
+ return ret;
+ }
+
+ ret = platform_driver_register(&cci_devfreq_driver);
+ if (ret)
+ devfreq_remove_governor(&mtk_cci_devfreq_governor);
+
+ return ret;
+}
+module_init(mtk_cci_devfreq_init)
+
+static void __exit mtk_cci_devfreq_exit(void)
+{
+ int ret = 0;
+
+ platform_driver_unregister(&cci_devfreq_driver);
+
+ ret = devfreq_remove_governor(&mtk_cci_devfreq_governor);
+ if (ret)
+ pr_err("%s: failed to remove governor: %d\n", __func__, ret);
+}
+module_exit(mtk_cci_devfreq_exit)
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Mediatek CCI devfreq driver");
+MODULE_AUTHOR("andrew-sh.cheng");
+
--
1.8.1.1.dirty