thermal/drivers/cpuidle_cooling: Change the registration function

Today, there is no user for the cpuidle cooling device. The targetted
platform is ARM and ARM64.

The cpuidle and the cpufreq cooling device are based on the device tree.

As the cpuidle cooling device can have its own configuration depending
on the platform and the available idle states. The DT node description
will give the optional properties to set the cooling device up.

Do no longer rely on the CPU node which is prone to error and will
lead to a confusion in the DT because the cpufreq cooling device is
also using it. Let initialize the cpuidle cooling device with the DT
binding.

This was tested on:
 - hikey960
 - hikey6220
 - rock960
 - db845c
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Reviewed-by: Amit Kucheria <amit.kucheria@linaro.org>
Tested-by: Amit Kucheria <amit.kucheria@linaro.org>
Link: https://lore.kernel.org/r/20200429103644.5492-3-daniel.lezcano@linaro.org

drivers/thermal/cpuidle_cooling.c

@@ -5,11 +5,14 @@
  *  Author: Daniel Lezcano <daniel.lezcano@linaro.org>
  *
  */
+#define pr_fmt(fmt) "cpuidle cooling: " fmt
+
 #include <linux/cpu_cooling.h>
 #include <linux/cpuidle.h>
 #include <linux/err.h>
 #include <linux/idle_inject.h>
 #include <linux/idr.h>
+#include <linux/of_device.h>
 #include <linux/slab.h>
 #include <linux/thermal.h>
 
@@ -154,22 +157,25 @@ static struct thermal_cooling_device_ops cpuidle_cooling_ops = {
 };
 
 /**
- * cpuidle_of_cooling_register - Idle cooling device initialization function
+ * __cpuidle_cooling_register: register the cooling device
  * @drv: a cpuidle driver structure pointer
- * @np: a node pointer to a device tree cooling device node
+ * @np: a device node structure pointer used for the thermal binding
  *
- * This function is in charge of creating a cooling device per cpuidle
- * driver and register it to thermal framework.
+ * This function is in charge of allocating the cpuidle cooling device
+ * structure, the idle injection, initialize them and register the
+ * cooling device to the thermal framework.
  *
- * Return: zero on success, or negative value corresponding to the
- * error detected in the underlying subsystems.
+ * Return: zero on success, a negative value returned by one of the
+ * underlying subsystem in case of error
  */
-int cpuidle_of_cooling_register(struct device_node *np,
-				struct cpuidle_driver *drv)
+static int __cpuidle_cooling_register(struct device_node *np,
+				      struct cpuidle_driver *drv)
 {
 	struct idle_inject_device *ii_dev;
 	struct cpuidle_cooling_device *idle_cdev;
 	struct thermal_cooling_device *cdev;
+	unsigned int idle_duration_us = TICK_USEC;
+	unsigned int latency_us = UINT_MAX;
 	char dev_name[THERMAL_NAME_LENGTH];
 	int id, ret;
 
@@ -191,7 +197,11 @@ int cpuidle_of_cooling_register(struct device_node *np,
 		goto out_id;
 	}
 
-	idle_inject_set_duration(ii_dev, TICK_USEC, TICK_USEC);
+	of_property_read_u32(np, "duration-us", &idle_duration_us);
+	of_property_read_u32(np, "exit-latency-us", &latency_us);
+
+	idle_inject_set_duration(ii_dev, TICK_USEC, idle_duration_us);
+	idle_inject_set_latency(ii_dev, latency_us);
 
 	idle_cdev->ii_dev = ii_dev;
 
@@ -204,6 +214,9 @@ int cpuidle_of_cooling_register(struct device_node *np,
 		goto out_unregister;
 	}
 
+	pr_debug("%s: Idle injection set with idle duration=%u, latency=%u\n",
+		 dev_name, idle_duration_us, latency_us);
+
 	return 0;
 
 out_unregister:
@@ -221,12 +234,38 @@ int cpuidle_of_cooling_register(struct device_node *np,
  * @drv: a cpuidle driver structure pointer
  *
  * This function is in charge of creating a cooling device per cpuidle
- * driver and register it to thermal framework.
+ * driver and register it to the thermal framework.
  *
  * Return: zero on success, or negative value corresponding to the
  * error detected in the underlying subsystems.
  */
-int cpuidle_cooling_register(struct cpuidle_driver *drv)
+void cpuidle_cooling_register(struct cpuidle_driver *drv)
 {
-	return cpuidle_of_cooling_register(NULL, drv);
+	struct device_node *cooling_node;
+	struct device_node *cpu_node;
+	int cpu, ret;
+
+	for_each_cpu(cpu, drv->cpumask) {
+
+		cpu_node = of_cpu_device_node_get(cpu);
+
+		cooling_node = of_get_child_by_name(cpu_node, "thermal-idle");
+
+		of_node_put(cpu_node);
+
+		if (!cooling_node) {
+			pr_debug("'thermal-idle' node not found for cpu%d\n", cpu);
+			continue;
+		}
+
+		ret = __cpuidle_cooling_register(cooling_node, drv);
+
+		of_node_put(cooling_node);
+
+		if (ret) {
+			pr_err("Failed to register the cpuidle cooling device" \
+			       "for cpu%d: %d\n", cpu, ret);
+			break;
+		}
+	}
 }

include/linux/cpu_cooling.h

@@ -63,18 +63,10 @@ of_cpufreq_cooling_register(struct cpufreq_policy *policy)
 struct cpuidle_driver;
 
 #ifdef CONFIG_CPU_IDLE_THERMAL
-int cpuidle_cooling_register(struct cpuidle_driver *drv);
-int cpuidle_of_cooling_register(struct device_node *np,
-				struct cpuidle_driver *drv);
+void cpuidle_cooling_register(struct cpuidle_driver *drv);
 #else /* CONFIG_CPU_IDLE_THERMAL */
-static inline int cpuidle_cooling_register(struct cpuidle_driver *drv)
+static inline void cpuidle_cooling_register(struct cpuidle_driver *drv)
 {
-	return 0;
-}
-static inline int cpuidle_of_cooling_register(struct device_node *np,
-					      struct cpuidle_driver *drv)
-{
-	return 0;
 }
 #endif /* CONFIG_CPU_IDLE_THERMAL */