[RFC PATCH 2/5] thermal: cpu_cooling: Add notifications support for the clients

[amit daniel kachhap]

On Fri, May 16, 2014 at 11:02 PM, Javi Merino <javi.merino at arm.com> wrote:
> Hi Amit,
>
> On Thu, May 08, 2014 at 03:37:57PM +0100, 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
>>
>> 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 at samsung.com>
>> ---
>>  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;
>> +
>
> I think this should all be inside the "if (count > 0)".  If not, then
> remove it, as it is dead code now.
yes this looks buggy. Will remove them. thanks
>
> Cheers,
> Javi
>
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