This patch adds notification support for those clients of cpu_cooling
APIs which may want to do something interesting after receiving these
cpu_cooling events. The notifier structure passed is of both Set/Get type.
The notfications events can be of type,
1. CPU_COOLING_SET_STATE_PRE
2. CPU_COOLING_SET_STATE_POST
3. CPU_COOLING_GET_CUR_STATE
4. CPU_COOLING_GET_MAX_STATE
The advantages of these notfications is to differentiate between different
P states in the cpufreq table and the cooling states. The clients of these
events may group few P states into 1 cooling states. Also some more cooling
states can be enabled when the maximum of P state is reached. Post notifications
can be used for those cases.
Signed-off-by: Amit Daniel Kachhap <amit.daniel@xxxxxxxxxxx>
---
drivers/thermal/cpu_cooling.c | 99 +++++++++++++++++++++++++++++++++++++++-
include/linux/cpu_cooling.h | 55 +++++++++++++++++++++++
2 files changed, 151 insertions(+), 3 deletions(-)
diff --git a/drivers/thermal/cpu_cooling.c b/drivers/thermal/cpu_cooling.c
index 21f44d4..e2aeb36 100644
--- a/drivers/thermal/cpu_cooling.c
+++ b/drivers/thermal/cpu_cooling.c
@@ -50,6 +50,7 @@ struct cpufreq_cooling_device {
unsigned int cpufreq_state;
unsigned int cpufreq_val;
struct cpumask allowed_cpus;
+ struct cpufreq_cooling_status request_status;
struct list_head node;
};
static DEFINE_IDR(cpufreq_idr);
@@ -59,6 +60,8 @@ static DEFINE_MUTEX(cooling_cpufreq_lock);
#define NOTIFY_INVALID NULL
static struct cpufreq_cooling_device *notify_device;
+/* Notfier list to validates/updates the cpufreq cooling states */
+static BLOCKING_NOTIFIER_HEAD(cpufreq_cooling_state_notifier_list);
/* A list to hold all the cpufreq cooling devices registered */
static LIST_HEAD(cpufreq_cooling_list);
@@ -266,6 +269,21 @@ static unsigned int get_cpu_frequency(unsigned int cpu, unsigned long level)
return freq;
}
+static int
+cpufreq_cooling_notify_states(struct cpufreq_cooling_status *request,
+ enum cpu_cooling_state_ops op)
+{
+ /* Invoke the notifiers which have registered for this state change */
+ if (op == CPU_COOLING_SET_STATE_PRE ||
+ op == CPU_COOLING_SET_STATE_POST ||
+ op == CPU_COOLING_GET_MAX_STATE ||
+ op == CPU_COOLING_GET_CUR_STATE) {
+ blocking_notifier_call_chain(
+ &cpufreq_cooling_state_notifier_list, op, request);
+ }
+ return 0;
+}
+
/**
* cpufreq_apply_cooling - function to apply frequency clipping.
* @cpufreq_device: cpufreq_cooling_device pointer containing frequency
@@ -285,9 +303,18 @@ static int cpufreq_apply_cooling(struct cpufreq_cooling_device *cpufreq_device,
struct cpumask *mask = &cpufreq_device->allowed_cpus;
unsigned int cpu = cpumask_any(mask);
+ cpufreq_device->request_status.cur_state =
+ cpufreq_device->cpufreq_state;
+ cpufreq_device->request_status.new_state = cooling_state;
+
+ cpufreq_cooling_notify_states(&cpufreq_device->request_status,
+ CPU_COOLING_SET_STATE_PRE);
+
+ cooling_state = cpufreq_device->request_status.new_state;
/* Check if the old cooling action is same as new cooling action */
- if (cpufreq_device->cpufreq_state == cooling_state)
+ if (cpufreq_device->cpufreq_state ==
+ cpufreq_device->request_status.new_state)
return 0;
clip_freq = get_cpu_frequency(cpu, cooling_state);
@@ -304,7 +331,8 @@ static int cpufreq_apply_cooling(struct cpufreq_cooling_device *cpufreq_device,
}
notify_device = NOTIFY_INVALID;
-
+ cpufreq_cooling_notify_states(&cpufreq_device->request_status,
+ CPU_COOLING_SET_STATE_POST);
return 0;
}
@@ -383,6 +411,11 @@ static int cpufreq_get_max_state(struct thermal_cooling_device *cdev,
if (count > 0)
*state = count;
+ cpufreq_device->request_status.max_state = count;
+ cpufreq_cooling_notify_states(&cpufreq_device->request_status,
+ CPU_COOLING_GET_MAX_STATE);
+ *state = cpufreq_device->request_status.max_state;
+
return ret;
}
@@ -410,8 +443,12 @@ static int cpufreq_get_cur_state(struct thermal_cooling_device *cdev,
/* Cooling device pointer not found */
return -EINVAL;
}
+ cpufreq_device->request_status.cur_state =
+ cpufreq_device->cpufreq_state;
+ cpufreq_cooling_notify_states(&cpufreq_device->request_status,
+ CPU_COOLING_GET_CUR_STATE);
- *state = cpufreq_device->cpufreq_state;
+ *state = cpufreq_device->request_status.cur_state;
return 0;
}
@@ -520,6 +557,7 @@ __cpufreq_cooling_register(struct device_node *np,
}
cpufreq_dev->cool_dev = cool_dev;
cpufreq_dev->cpufreq_state = 0;
+ cpufreq_dev->request_status.devdata = devdata;
mutex_lock(&cooling_cpufreq_lock);
/* Register the notifier for first cpufreq cooling device */
@@ -614,3 +652,58 @@ void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev)
kfree(cpufreq_dev);
}
EXPORT_SYMBOL_GPL(cpufreq_cooling_unregister);
+
+/**
+ * cpufreq_cooling_register_notifier - register a driver with cpufreq cooling.
+ * @nb: notifier function to register.
+ * @list: CPU_COOLING_STATE_NOTIFIER type.
+ *
+ * Add a driver to receive cpufreq cooling notifications like current state,
+ * max state and set state. The drivers after reading the events can perform
+ * some mapping between the P states and cooling states like grouping some P
+ * states into 1 cooling state.
+ *
+ * Return: 0 (success)
+ */
+int cpufreq_cooling_register_notifier(struct notifier_block *nb,
+ unsigned int list)
+{
+ int ret = 0;
+ switch (list) {
+ case CPU_COOLING_STATE_NOTIFIER:
+ ret = blocking_notifier_chain_register(
+ &cpufreq_cooling_state_notifier_list, nb);
+ break;
+ default:
+ ret = -EINVAL;
+ }
+ return ret;
+}
+EXPORT_SYMBOL_GPL(cpufreq_cooling_register_notifier);
+
+/**
+ * cpufreq_cooling_unregister_notifier - unregisters a driver with cpufreq
+ * cooling.
+ * @nb: notifier function to unregister.
+ * @list: CPU_COOLING_STATE_NOTIFIER type.
+ *
+ * Removes a driver to receive further cpufreq cooling notifications.
+ *
+ * Return: 0 (success)
+ */
+int cpufreq_cooling_unregister_notifier(struct notifier_block *nb,
+ unsigned int list)
+{
+ int ret = 0;
+ switch (list) {
+ case CPU_COOLING_STATE_NOTIFIER:
+ ret = blocking_notifier_chain_unregister(
+ &cpufreq_cooling_state_notifier_list, nb);
+ break;
+ default:
+ ret = -EINVAL;
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(cpufreq_cooling_unregister_notifier);
diff --git a/include/linux/cpu_cooling.h b/include/linux/cpu_cooling.h
index aaef7d8..f786935 100644
--- a/include/linux/cpu_cooling.h
+++ b/include/linux/cpu_cooling.h
@@ -28,6 +28,22 @@
#include <linux/thermal.h>
#include <linux/cpumask.h>
+#define CPU_COOLING_STATE_NOTIFIER (0)
+
+enum cpu_cooling_state_ops {
+ CPU_COOLING_SET_STATE_PRE,
+ CPU_COOLING_SET_STATE_POST,
+ CPU_COOLING_GET_CUR_STATE,
+ CPU_COOLING_GET_MAX_STATE,
+};
+
+struct cpufreq_cooling_status {
+ unsigned long cur_state;
+ unsigned long new_state;
+ unsigned long max_state;
+ void *devdata;
+};
+
#ifdef CONFIG_CPU_THERMAL
/**
* cpufreq_cooling_register - function to create cpufreq cooling device.
@@ -62,6 +78,34 @@ of_cpufreq_cooling_register(struct device_node *np,
void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev);
unsigned long cpufreq_cooling_get_level(unsigned int cpu, unsigned int freq);
+
+/**
+ * cpufreq_cooling_register_notifier - register a driver with cpufreq cooling.
+ * @nb: notifier function to register.
+ * @list: CPU_COOLING_STATE_NOTIFIER type.
+ *
+ * Add a driver to receive cpufreq cooling notifications like current state,
+ * max state and set state. The drivers after reading the events can perform
+ * some mapping between the P states and cooling states like grouping some P
+ * states into 1 cooling state.
+ *
+ * Return: 0 (success)
+ */
+int cpufreq_cooling_register_notifier(struct notifier_block *nb,
+ unsigned int list);
+
+/**
+ * cpufreq_cooling_unregister_notifier - unregisters a driver with cpufreq
+ * cooling.
+ * @nb: notifier function to unregister.
+ * @list: CPU_COOLING_STATE_NOTIFIER type.
+ *
+ * Removes a driver to receive further cpufreq cooling notifications.
+ *
+ * Return: 0 (success)
+ */
+int cpufreq_cooling_unregister_notifier(struct notifier_block *nb,
+ unsigned int list);
#else /* !CONFIG_CPU_THERMAL */
static inline struct thermal_cooling_device *
cpufreq_cooling_register(const struct cpumask *clip_cpus, void *devdata)
@@ -84,6 +128,17 @@ unsigned long cpufreq_cooling_get_level(unsigned int cpu, unsigned int freq)
{
return THERMAL_CSTATE_INVALID;
}
+static inline int
+cpufreq_cooling_register_notifier(struct notifier_block *nb, unsigned int list)
+{
+ return 0;
+}
+static inline int
+cpufreq_cooling_unregister_notifier(struct notifier_block *nb,
+ unsigned int list)
+{
+ return 0;
+}
#endif /* CONFIG_CPU_THERMAL */
#endif /* __CPU_COOLING_H__ */
--
1.7.1
