Date:   Wed, 15 Apr 2020 11:09:59 +0800
From:   zhang.lyra@...il.com
To:     linux-pm@...r.kernel.org
Cc:     Amit Daniel Kachhap <amit.kachhap@...il.com>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Javi Merino <javi.merino@...nel.org>,
        Zhang Rui <rui.zhang@...el.com>,
        Amit Kucheria <amit.kucheria@...durent.com>,
        linux-kernel@...r.kernel.org, Orson Zhai <orsonzhai@...il.com>,
        Baolin Wang <baolin.wang7@...il.com>,
        Chunyan Zhang <zhang.lyra@...il.com>,
        Chunyan Zhang <chunyan.zhang@...soc.com>
Subject: [RFC PATCH v1 2/2] thermal/drivers/sprd_cpu_cooling: Add platform mitigation thermal driver

From: Jeson Gao <jeson.gao@...soc.com>

This driver provides a further core ctrl policy to reduce temperature for
unisoc platform.

CPU unplug or isolation usually would be used for core ctrl policy.

This dirver is showing an example of using core ctrl policy.

Signed-off-by: Jeson Gao <jeson.gao@...soc.com>
Signed-off-by: Chunyan Zhang <zhang.lyra@...il.com>
---
 drivers/thermal/Kconfig            |   8 +
 drivers/thermal/Makefile           |   1 +
 drivers/thermal/sprd_cpu_cooling.c | 340 +++++++++++++++++++++++++++++
 3 files changed, 349 insertions(+)
 create mode 100644 drivers/thermal/sprd_cpu_cooling.c

diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
index 91af271e9bb0..41a57b0a0d57 100644
--- a/drivers/thermal/Kconfig
+++ b/drivers/thermal/Kconfig
@@ -490,4 +490,12 @@ config SPRD_THERMAL
 	help
 	  Support for the Spreadtrum thermal sensor driver in the Linux thermal
 	  framework.
+
+config SPRD_CPU_COOLING
+	tristate "sprd cpu cooling support"
+	depends on CPU_FREQ_THERMAL
+	help
+	  This implements the sprd cpu cooling mechanism to mitigate temperature
+	  rising.
+
 endif
diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
index 8c8ed7b79915..403184299485 100644
--- a/drivers/thermal/Makefile
+++ b/drivers/thermal/Makefile
@@ -60,3 +60,4 @@ obj-$(CONFIG_ZX2967_THERMAL)	+= zx2967_thermal.o
 obj-$(CONFIG_UNIPHIER_THERMAL)	+= uniphier_thermal.o
 obj-$(CONFIG_AMLOGIC_THERMAL)     += amlogic_thermal.o
 obj-$(CONFIG_SPRD_THERMAL)	+= sprd_thermal.o
+obj-$(CONFIG_SPRD_CPU_COOLING)	+= sprd_cpu_cooling.o
diff --git a/drivers/thermal/sprd_cpu_cooling.c b/drivers/thermal/sprd_cpu_cooling.c
new file mode 100644
index 000000000000..18ce41e2bd5a
--- /dev/null
+++ b/drivers/thermal/sprd_cpu_cooling.c
@@ -0,0 +1,340 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2020 Spreadtrum Communications Inc.
+
+#include <linux/thermal.h>
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/cpu.h>
+#include <linux/sched.h>
+#include <linux/platform_device.h>
+#include <linux/printk.h>
+#include <linux/cpufreq.h>
+
+#include <linux/cpu_cooling.h>
+
+struct sprd_cooling_cluster {
+	int id;
+	int cpu;
+	int cpus;
+	u32 min_freq;
+	struct cpufreq_policy policy;
+};
+
+struct sprd_cooling_data {
+	int nr_clusters;
+	struct sprd_cooling_cluster *cluster;
+};
+
+static void sprd_update_target_cpus(struct cpufreq_policy *policy,
+				    u32 target_cpus)
+{
+	int ret, cpu, first;
+	u32 curr_online_cpus, ncpus;
+
+	ncpus = cpumask_weight(policy->related_cpus);
+	curr_online_cpus = cpumask_weight(policy->cpus);
+	first = cpumask_first(policy->related_cpus);
+
+	if (target_cpus > curr_online_cpus) {
+		cpu = first;
+		for_each_cpu(cpu, policy->related_cpus) {
+			if (curr_online_cpus == target_cpus)
+				break;
+			if ((target_cpus > curr_online_cpus) &&
+			    !cpu_online(cpu)) {
+				ret = add_cpu(cpu);
+				if (!ret && cpu_online(cpu))
+					curr_online_cpus++;
+			}
+		}
+	} else if (target_cpus < curr_online_cpus) {
+		for (cpu = (first + ncpus - 1); cpu >= first; cpu--) {
+			if (curr_online_cpus == target_cpus)
+				break;
+			if ((target_cpus < curr_online_cpus) &&
+			    cpu_online(cpu)) {
+				ret = remove_cpu(cpu);
+				if (!ret && !cpu_online(cpu))
+					curr_online_cpus--;
+			}
+		}
+	}
+}
+
+static void sprd_estimate_down_cpus(struct cpufreq_policy *policy,
+				    u32 load, u32 normalised_power,
+				    u32 freq_power)
+{
+	int i = 0;
+	u32 target_cpus, online_cpus;
+	u32 avg_load, estimate_power =  0;
+
+	if (normalised_power) {
+		online_cpus = cpumask_weight(policy->cpus);
+		if (!online_cpus)
+			return;
+
+		avg_load = (load / online_cpus) ?: 1;
+		do {
+			estimate_power += (freq_power * avg_load) / 100;
+			if (estimate_power > normalised_power)
+				break;
+			i++;
+		} while (i < online_cpus);
+
+		target_cpus = max(i, 0);
+	} else
+		target_cpus = 0;
+
+	sprd_update_target_cpus(policy, target_cpus);
+}
+
+static void sprd_estimate_up_cpus(struct cpufreq_policy *policy,
+				  u32 load, u32 normalised_power,
+				  u32 freq_power)
+{
+	int i = 0, ncpus;
+	u32 target_cpus;
+	u32 avg_load, estimate_power =  0;
+
+	ncpus = cpumask_weight(policy->related_cpus);
+	avg_load = (load / ncpus) ?: 1;
+
+	do {
+		estimate_power += (freq_power * avg_load) / 100;
+		if (estimate_power > normalised_power)
+			break;
+		i++;
+	} while (i < ncpus);
+
+	target_cpus = min(i, ncpus);
+	sprd_update_target_cpus(policy, target_cpus);
+}
+
+static void sprd_keep_cpus(struct cpufreq_policy *policy)
+{
+	u32 online_cpus;
+
+	online_cpus = cpumask_weight(policy->cpus);
+	sprd_update_target_cpus(policy, online_cpus);
+}
+
+static int sprd_cpufreq_cpu_ctrl(struct cpufreq_policy *policy,
+				 u32 load, u32 normalised_power,
+				 u32 freq_power)
+{
+	unsigned int ncpus, online_cpus;
+
+	ncpus = cpumask_weight(policy->related_cpus);
+	online_cpus = cpumask_weight(policy->cpus);
+
+	if (normalised_power <  freq_power)
+		sprd_estimate_down_cpus(policy, load,
+					normalised_power, freq_power);
+	else if (online_cpus < ncpus)
+		sprd_estimate_up_cpus(policy, load,
+				      normalised_power, freq_power);
+	else
+		sprd_keep_cpus(policy);
+
+	return 0;
+}
+
+static void sprd_cpufreq_min_freq_limit(struct cpufreq_policy *policy,
+					u32 *target_freq)
+{
+	struct sprd_cooling_cluster *cluster =
+		container_of(policy, struct sprd_cooling_cluster, policy);
+
+	if (*target_freq < cluster->min_freq)
+		*target_freq = cluster->min_freq;
+}
+
+struct cpufreq_cooling_plat_ops plat_ops = {
+	.cpufreq_plat_cpu_ctrl = sprd_cpufreq_cpu_ctrl,
+	.cpufreq_plat_min_freq_limit = sprd_cpufreq_min_freq_limit,
+};
+
+static int sprd_get_cluster_counts(void)
+{
+	int cpu = 0, core_num = -1;
+	int cluster_num = 0;
+
+	do {
+		core_num = cpumask_weight(topology_core_cpumask(cpu));
+		if (core_num > 0) {
+			cpu = cpu + core_num;
+			cluster_num++;
+		} else
+			break;
+	} while (cpu > 0);
+
+	return cluster_num;
+}
+
+static int sprd_cpu_cooing_ops_register(struct platform_device *pdev)
+{
+	int id, ret = 0;
+	struct thermal_cooling_device *cdev;
+	struct sprd_cooling_cluster *cluster;
+	struct sprd_cooling_data *data = platform_get_drvdata(pdev);
+
+	for (id = 0; id < data->nr_clusters; id++) {
+		cluster = &data->cluster[id];
+		cdev = cluster->policy.cdev;
+		if (cdev) {
+			ret = cpufreq_cooling_plat_ops_register(cdev,
+								&plat_ops);
+			if (ret < 0) {
+				dev_err(&pdev->dev,
+					"CPU%d: failed to register platform function\n",
+					cluster->cpu);
+				break;
+			}
+		} else {
+			ret = -ENODEV;
+			dev_err(&pdev->dev,
+				"CPU%d: failed to get thermal device\n",
+				cluster->cpu);
+			break;
+		}
+	}
+
+	return ret;
+}
+
+static int sprd_cpu_cooing_ops_unregister(struct platform_device *pdev)
+{
+	int id, ret = 0;
+	struct thermal_cooling_device *cdev;
+	struct sprd_cooling_cluster *cluster;
+	struct sprd_cooling_data *data = platform_get_drvdata(pdev);
+
+	for (id = 0; id < data->nr_clusters; id++) {
+		cluster = &data->cluster[id];
+		cdev = cluster->policy.cdev;
+		if (cdev) {
+			ret = cpufreq_cooling_plat_ops_unregister(cdev);
+			if (ret < 0) {
+				dev_err(&pdev->dev,
+					"cpu%d: failed to unregister platform function\n",
+					cluster->cpu);
+				break;
+			}
+		} else {
+			dev_err(&pdev->dev,
+				"cpu%d: failed to get thermal device\n",
+				cluster->cpu);
+			ret = -ENODEV;
+			break;
+		}
+	}
+
+	return ret;
+}
+
+static int sprd_init_cooling_cluster(struct platform_device *pdev)
+{
+	int cpu = 0, id, core_num, ret = 0;
+	struct sprd_cooling_cluster *cluster;
+	struct sprd_cooling_data *data = platform_get_drvdata(pdev);
+
+	do {
+		core_num = cpumask_weight(topology_core_cpumask(cpu));
+		id = topology_physical_package_id((cpu));
+		if (core_num > 0 && id >= 0) {
+			cluster = &data->cluster[id];
+			cluster->id = id;
+			cluster->cpu = cpu;
+			cluster->cpus = core_num;
+			ret = cpufreq_get_policy(&(cluster->policy), cpu);
+			if (ret < 0) {
+				dev_err(&pdev->dev,
+					"CPU%d failed to get policy\n",
+					cpu);
+				break;
+			}
+
+			cpu = cpu + core_num;
+		} else
+			break;
+
+	} while (cpu > 0);
+
+	return ret;
+}
+
+static int sprd_cpu_cooling_probe(struct platform_device *pdev)
+{
+	int ret = -1;
+	int counts = 0;
+	struct sprd_cooling_data *data;
+	struct device *dev = &pdev->dev;
+
+	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	counts = sprd_get_cluster_counts();
+	data->nr_clusters = counts;
+	data->cluster = devm_kzalloc(dev,
+				     sizeof(*data->cluster) * data->nr_clusters,
+				     GFP_KERNEL);
+	if (!data->cluster)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, data);
+
+	ret = sprd_init_cooling_cluster(pdev);
+	if (ret < 0) {
+		dev_err(dev, "Failed to init cooling cluster\n");
+		return ret;
+	}
+
+	ret = sprd_cpu_cooing_ops_register(pdev);
+	if (ret < 0) {
+		dev_err(dev, "Failed to register cooling callback function\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int sprd_cpu_cooling_remove(struct platform_device *pdev)
+{
+	int ret;
+
+	ret = sprd_cpu_cooing_ops_unregister(pdev);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Failed to unregister cooling callback function\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static struct platform_driver sprd_cpu_cooling_driver = {
+	.probe = sprd_cpu_cooling_probe,
+	.remove = sprd_cpu_cooling_remove,
+	.driver = {
+		   .owner = THIS_MODULE,
+		   .name = "sprd_cpu_cooling",
+		   },
+};
+static int __init sprd_cpu_cooling_init(void)
+{
+	return platform_driver_register(&sprd_cpu_cooling_driver);
+}
+
+static void __exit sprd_cpu_cooling_exit(void)
+{
+	platform_driver_unregister(&sprd_cpu_cooling_driver);
+}
+
+module_init(sprd_cpu_cooling_init)
+module_exit(sprd_cpu_cooling_exit);
+
+MODULE_DESCRIPTION("sprd cpu cooling");
+MODULE_LICENSE("GPL");
-- 
2.20.1

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