1 files changed, 444 insertions, 0 deletions

diff --git a/drivers/devfreq/mtk-cci-devfreq.c b/drivers/devfreq/mtk-cci-devfreq.c
new file mode 100644
index 0000000000..83a73f0ccd
--- /dev/null
+++ b/drivers/devfreq/mtk-cci-devfreq.c
@@ -0,0 +1,444 @@
+// 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/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;
+	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;
+	cci_pll = clk_get_parent(drv->cci_clk);
+
+	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");