Hello Amit,
On Thu, May 08, 2014 at 08:07:57PM +0530, Amit Daniel Kachhap wrote: > 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 What do you think about expanding this feature to all cooling devices? I mean, why should we restrict to cpu(freq) cooling? The clock cooling device I posted (and that I plan to merge soon) should also benefit of this infrastructure. The clock cooling is for the context of other processing units, that do not benefit of cpufreq. > > 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 <[email protected]> > --- > 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); > + Can a listener block/abort/postpone a state transition? > + cooling_state = cpufreq_device->request_status.new_state; > So you are proposing listeners can have control on target cpufreq state, right? Or did I get it wrong? I think we should have this better documented. Besides, if that is the case, what happens if we have several listeners? > /* 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; > + same question here, who determines the priorities when several listeners are present in the system? > 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); > ditto. > - *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); The exported symbols must be documented under Documentation/ too. > 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 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to [email protected] > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
