soc: rockchip: system_monitor: on/off cpu according to temperature

Change-Id: Ie2c55dd4c11700c0446cf0abec7e580f6abda8fe
Signed-off-by: Finley Xiao <finley.xiao@rock-chips.com>

Documentation/devicetree/bindings/soc/rockchip/rockchip_system_monitor.txt

@@ -8,11 +8,25 @@ Required properties:
 Optional properties:
 - rockchip,video-4k-offline-cpus: A string containing cpus which will be killed
 			when play 4k video.
+- rockchip,thermal-zone: A thermal zone node containing thermal sensor,
+			it's used to get the current temperature.
+- rockchip,polling-delay: The maximum number of milliseconds to wait
+			between polls.
+- rockchip,offline-cpu-temp: An integer indicating the trip temperature level.
+- rockchip,temp-hysteresis: A low hysteresis value on rockchip,offline-cpu-temp
+			property (above).
+- rockchip,temp-offline-cpus: A string containing cpus which will be killed
+			when temperature is high.
 
 Example:
 
 system-monitor {
 	compatible = "rockchip,system-monitor";
 
+	rockchip,thermal-zone = "soc-thermal";
+	rockchip,polling-delay = <200>; /* milliseconds */
+	rockchip,offline-cpu-temp = <110000>; /* millicelsius */
+	rockchip,temp-offline-cpus = "2-3";
+
 	rockchip,video-4k-offline-cpus = "2-3";
 };

drivers/soc/rockchip/rockchip_system_monitor.c

@@ -14,9 +14,11 @@
 #include <linux/platform_device.h>
 #include <linux/uaccess.h>
 #include <linux/slab.h>
+#include <linux/thermal.h>
 #include <soc/rockchip/rockchip-system-status.h>
 
 #define VIDEO_1080P_SIZE	(1920 * 1080)
+#define THERMAL_POLLING_DELAY	200 /* milliseconds */
 
 struct video_info {
 	unsigned int width;
@@ -39,9 +41,17 @@ struct system_monitor {
 	struct device *dev;
 	struct cpumask video_4k_offline_cpus;
 	struct cpumask status_offline_cpus;
+	struct cpumask temp_offline_cpus;
 	struct cpumask offline_cpus;
 	struct notifier_block status_nb;
 	struct kobject *kobj;
+
+	struct thermal_zone_device *tz;
+	struct delayed_work thermal_work;
+	int offline_cpus_temp;
+	int temp_hysteresis;
+	unsigned int delay;
+	bool is_temp_offline;
 };
 
 static unsigned long system_status;
@@ -49,6 +59,7 @@ static unsigned long ref_count[32] = {0};
 
 static DEFINE_MUTEX(system_status_mutex);
 static DEFINE_MUTEX(video_info_mutex);
+static DEFINE_MUTEX(cpu_on_off_mutex);
 
 static LIST_HEAD(video_info_list);
 static struct system_monitor *system_monitor;
@@ -354,26 +365,58 @@ static struct system_monitor_attr status =
 static int rockchip_system_monitor_parse_dt(struct system_monitor *monitor)
 {
 	struct device_node *np = monitor->dev->of_node;
-	const char *buf = NULL;
+	const char *tz_name, *buf = NULL;
 
-	if (!of_property_read_string(np, "rockchip,video-4k-offline-cpus",
-				     &buf))
+	if (of_property_read_string(np, "rockchip,video-4k-offline-cpus", &buf))
+		cpumask_clear(&system_monitor->video_4k_offline_cpus);
+	else
 		cpulist_parse(buf, &monitor->video_4k_offline_cpus);
 
+	if (of_property_read_string(np, "rockchip,thermal-zone", &tz_name))
+		goto out;
+	monitor->tz = thermal_zone_get_zone_by_name(tz_name);
+	if (IS_ERR(monitor->tz)) {
+		monitor->tz = NULL;
+		goto out;
+	}
+	if (of_property_read_u32(np, "rockchip,polling-delay",
+				 &monitor->delay))
+		monitor->delay = THERMAL_POLLING_DELAY;
+
+	if (of_property_read_string(np, "rockchip,temp-offline-cpus",
+				    &buf))
+		cpumask_clear(&system_monitor->temp_offline_cpus);
+	else
+		cpulist_parse(buf, &system_monitor->temp_offline_cpus);
+
+	if (of_property_read_u32(np, "rockchip,offline-cpu-temp",
+				 &system_monitor->offline_cpus_temp))
+		system_monitor->offline_cpus_temp = INT_MAX;
+	of_property_read_u32(np, "rockchip,temp-hysteresis",
+			     &system_monitor->temp_hysteresis);
+out:
 	return 0;
 }
 
 static void rockchip_system_monitor_cpu_on_off(void)
 {
 #ifdef CONFIG_HOTPLUG_CPU
+	struct cpumask online_cpus, offline_cpus;
 	unsigned int cpu;
-	struct cpumask online_cpus;
 
-	if (cpumask_equal(&system_monitor->offline_cpus,
-			  &system_monitor->status_offline_cpus))
-		return;
-	cpumask_copy(&system_monitor->offline_cpus,
-		     &system_monitor->status_offline_cpus);
+	mutex_lock(&cpu_on_off_mutex);
+
+	cpumask_clear(&offline_cpus);
+	if (system_monitor->is_temp_offline) {
+		cpumask_or(&offline_cpus, &system_monitor->status_offline_cpus,
+			   &system_monitor->temp_offline_cpus);
+	} else {
+		cpumask_copy(&offline_cpus,
+			     &system_monitor->status_offline_cpus);
+	}
+	if (cpumask_equal(&offline_cpus, &system_monitor->offline_cpus))
+		goto out;
+	cpumask_copy(&system_monitor->offline_cpus, &offline_cpus);
 	for_each_cpu(cpu, &system_monitor->offline_cpus) {
 		if (cpu_online(cpu))
 			cpu_down(cpu);
@@ -384,12 +427,58 @@ static void rockchip_system_monitor_cpu_on_off(void)
 		       &system_monitor->offline_cpus);
 	cpumask_xor(&online_cpus, cpu_online_mask, &online_cpus);
 	if (cpumask_empty(&online_cpus))
-		return;
+		goto out;
 	for_each_cpu(cpu, &online_cpus)
 		cpu_up(cpu);
+
+out:
+	mutex_unlock(&cpu_on_off_mutex);
 #endif
 }
 
+static void rockchip_system_monitor_temp_cpu_on_off(int temp)
+{
+	bool is_temp_offline;
+
+	if (cpumask_empty(&system_monitor->temp_offline_cpus))
+		return;
+
+	if (temp > system_monitor->offline_cpus_temp)
+		is_temp_offline = true;
+	else if (temp < system_monitor->offline_cpus_temp -
+		 system_monitor->temp_hysteresis)
+		is_temp_offline = false;
+	else
+		return;
+
+	if (system_monitor->is_temp_offline == is_temp_offline)
+		return;
+	system_monitor->is_temp_offline = is_temp_offline;
+	rockchip_system_monitor_cpu_on_off();
+}
+
+static void rockchip_system_monitor_thermal_update(void)
+{
+	int temp, ret;
+
+	ret = thermal_zone_get_temp(system_monitor->tz, &temp);
+	if (ret || temp == THERMAL_TEMP_INVALID)
+		goto out;
+
+	dev_dbg(system_monitor->dev, "temperature=%d\n", temp);
+
+	rockchip_system_monitor_temp_cpu_on_off(temp);
+
+out:
+	mod_delayed_work(system_freezable_wq, &system_monitor->thermal_work,
+			 msecs_to_jiffies(system_monitor->delay));
+}
+
+static void rockchip_system_monitor_thermal_check(struct work_struct *work)
+{
+	rockchip_system_monitor_thermal_update();
+}
+
 static void rockchip_system_status_cpu_on_off(unsigned long status)
 {
 	struct cpumask offline_cpus;
@@ -432,11 +521,17 @@ static int rockchip_system_monitor_probe(struct platform_device *pdev)
 	if (sysfs_create_file(system_monitor->kobj, &status.attr))
 		dev_err(dev, "failed to create system status sysfs\n");
 
-	cpumask_clear(&system_monitor->video_4k_offline_cpus);
 	cpumask_clear(&system_monitor->status_offline_cpus);
 	cpumask_clear(&system_monitor->offline_cpus);
 
 	rockchip_system_monitor_parse_dt(system_monitor);
+	if (system_monitor->tz) {
+		INIT_DELAYED_WORK(&system_monitor->thermal_work,
+				  rockchip_system_monitor_thermal_check);
+		mod_delayed_work(system_freezable_wq,
+				 &system_monitor->thermal_work,
+				 msecs_to_jiffies(system_monitor->delay));
+	}
 
 	system_monitor->status_nb.notifier_call =
 		rockchip_system_status_notifier;