Hi,

On 3/31/21 5:03 PM, andrew-sh.cheng wrote:
> On Thu, 2021-03-25 at 17:14 +0900, Chanwoo Choi wrote:
>> Hi,
>>
>> You are missing to add these patches to linux-pm mailing list.
>> Need to send them to linu-pm ML.
>>
>> Also, before received this series, I tried to clean-up these patches
>> on testing branch[1]. So that I add my comment with my clean-up case.
>> [1] 
>> https://urldefense.com/v3/__https://git.kernel.org/pub/scm/linux/kernel/git/chanwoo/linux.git/log/?h=devfreq-testing-passive-gov__;!!CTRNKA9wMg0ARbw!zIrzeDp9vPnm1_SDzVPuzqdHn3zWie9DnfBXaA-j9-CSrVc6aR9_rJQQiw81_CgAPh9XRRs$
>>  
>>
>> And 'Saravana Kannan <[email protected]>' is wrong email address.
>> Please update the email or drop this email.
> 
> Hi Chanwoo,
> 
> Thank you for the advices.
> I will resend patch v9 (add to linux-pm ML), remove this patch, and note
> that my patch set base on
> https://git.kernel.org/pub/scm/linux/kernel/git/chanwoo/linux.git/log/?h=devfreq-testing-passive-gov

I has not yet test this patch[1] on devfreq-testing-passive-gov branch.
So that if possible, I'd like you to test your patches with this patch[1] 
and then if there is no problem, could you send the next patches with patch[1]?

[1]https://git.kernel.org/pub/scm/linux/kernel/git/chanwoo/linux.git/commit/?h=devfreq-testing-passive-gov&id=39c80d11a8f42dd63ecea1e0df595a0ceb83b454

> 
> 
>>
>>
>> On 3/23/21 8:33 PM, Andrew-sh.Cheng wrote:
>>> From: Saravana Kannan <[email protected]>
>>>
>>> Many CPU architectures have caches that can scale independent of the
>>> CPUs. Frequency scaling of the caches is necessary to make sure that the
>>> cache is not a performance bottleneck that leads to poor performance and
>>> power. The same idea applies for RAM/DDR.
>>>
>>> To achieve this, this patch adds support for cpu based scaling to the
>>> passive governor. This is accomplished by taking the current frequency
>>> of each CPU frequency domain and then adjust the frequency of the cache
>>> (or any devfreq device) based on the frequency of the CPUs. It listens
>>> to CPU frequency transition notifiers to keep itself up to date on the
>>> current CPU frequency.
>>>
>>> To decide the frequency of the device, the governor does one of the
>>> following:
>>> * Derives the optimal devfreq device opp from required-opps property of
>>>   the parent cpu opp_table.
>>>
>>> * Scales the device frequency in proportion to the CPU frequency. So, if
>>>   the CPUs are running at their max frequency, the device runs at its
>>>   max frequency. If the CPUs are running at their min frequency, the
>>>   device runs at its min frequency. It is interpolated for frequencies
>>>   in between.
>>>
>>> Andrew-sh.Cheng change
>>> dev_pm_opp_xlate_opp to dev_pm_opp_xlate_required_opp devfreq->max_freq
>>> to devfreq->user_min_freq_req.data.freq.qos->min_freq.target_value
>>> after kernel-5.7
>>> Don't return -EINVAL in devfreq_passive_event_handler()
>>> since it doesn't handle DEVFREQ_GOV_SUSPEND DEVFREQ_GOV_RESUME cases.
>>>
>>> Signed-off-by: Saravana Kannan <[email protected]>
>>> [Sibi: Integrated cpu-freqmap governor into passive_governor]
>>> Signed-off-by: Sibi Sankar <[email protected]>
>>> Signed-off-by: Andrew-sh.Cheng <[email protected]>
>>> ---
>>>  drivers/devfreq/Kconfig            |   2 +
>>>  drivers/devfreq/governor_passive.c | 329 
>>> +++++++++++++++++++++++++++++++++++--
>>>  include/linux/devfreq.h            |  29 +++-
>>>  3 files changed, 342 insertions(+), 18 deletions(-)
>>>
>>> diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig
>>> index 00704efe6398..f56132b0ae64 100644
>>> --- a/drivers/devfreq/Kconfig
>>> +++ b/drivers/devfreq/Kconfig
>>> @@ -73,6 +73,8 @@ config DEVFREQ_GOV_PASSIVE
>>>       device. This governor does not change the frequency by itself
>>>       through sysfs entries. The passive governor recommends that
>>>       devfreq device uses the OPP table to get the frequency/voltage.
>>> +     Alternatively the governor can also be chosen to scale based on
>>> +     the online CPUs current frequency.
>>>  
>>>  comment "DEVFREQ Drivers"
>>>  
>>> diff --git a/drivers/devfreq/governor_passive.c 
>>> b/drivers/devfreq/governor_passive.c
>>> index b094132bd20b..9cc57b083839 100644
>>> --- a/drivers/devfreq/governor_passive.c
>>> +++ b/drivers/devfreq/governor_passive.c
>>> @@ -8,11 +8,103 @@
>>>   */
>>>  
>>>  #include <linux/module.h>
>>> +#include <linux/cpu.h>
>>> +#include <linux/cpufreq.h>
>>> +#include <linux/cpumask.h>
>>>  #include <linux/device.h>
>>>  #include <linux/devfreq.h>
>>> +#include <linux/slab.h>
>>>  #include "governor.h"
>>>  
>>> -static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>> +struct devfreq_cpu_state {
>>> +   unsigned int curr_freq;
>>> +   unsigned int min_freq;
>>> +   unsigned int max_freq;
>>> +   unsigned int first_cpu;
>>> +   struct device *cpu_dev;
>>> +   struct opp_table *opp_table;
>>> +};
>>
>> As I knew, the previous version has the description of structure
>> as following:  I wan to add the description like below.
>>
>> And if you have no any objection, I'd like you to order
>> the variables as following and use 'dev' instead of 'cpu_dev'
>> because this patch use the 'cpu_state->cpu_dev' at the multiple points.
>> I think that 'cpu_state->dev' is better than 'cpu_state->cpu_dev'.
>> Also, I prefer to use 'cur_freq' instead of 'curr_freq'
>> because devfreq subsystem uses 'cur_freq' for expressing the 'current 
>> frequency'.
>>
>> /**                                                                          
>>    
>>  * struct devfreq_cpu_state - Hold the per-cpu data                          
>>     
>>  * @dev:        reference to cpu device.                                     
>>    
>>  * @first_cpu:  the cpumask of the first cpu of a policy.                    
>>    
>>  * @opp_table:  reference to cpu opp table.                                  
>>    
>>  * @cur_freq:   the current frequency of the cpu.                            
>>    
>>  * @min_freq:   the min frequency of the cpu.                                
>>    
>>  * @max_freq:   the max frequency of the cpu.                                
>>    
>>  *                                                                           
>>    
>>  * This structure stores the required cpu_data of a cpu.                     
>>    
>>  * This is auto-populated by the governor.                                   
>>    
>>  */                                                                          
>>    
>> struct devfreq_cpu_state {                                                   
>>     
>>          struct device *dev;                                                 
>>     
>>          unsigned int first_cpu;                                             
>>     
>>
>>          struct opp_table *opp_table;                                        
>>     
>>          unsigned int cur_freq;                                              
>>     
>>          unsigned int min_freq;                                              
>>     
>>          unsigned int max_freq;                                              
>>     
>> };               
>>
>>
>>> +
>>> +static unsigned long xlate_cpufreq_to_devfreq(struct devfreq_passive_data 
>>> *data,
>>> +                                         unsigned int cpu)
>>> +{
>>> +   unsigned int cpu_min_freq, cpu_max_freq, cpu_curr_freq_khz, cpu_percent;
>>> +   unsigned long dev_min_freq, dev_max_freq, dev_max_state;
>>> +
>>> +   struct devfreq_cpu_state *cpu_state = data->cpu_state[cpu];
>>> +   struct devfreq *devfreq = (struct devfreq *)data->this;
>>> +   unsigned long *dev_freq_table = devfreq->profile->freq_table;
>>> +   struct dev_pm_opp *opp = NULL, *p_opp = NULL;
>>> +   unsigned long cpu_curr_freq, freq;
>>> +
>>> +   if (!cpu_state || cpu_state->first_cpu != cpu ||
>>> +       !cpu_state->opp_table || !devfreq->opp_table)
>>> +           return 0;
>>> +
>>> +   cpu_curr_freq = cpu_state->curr_freq * 1000;
>>> +   p_opp = devfreq_recommended_opp(cpu_state->cpu_dev, &cpu_curr_freq, 0);
>>> +   if (IS_ERR(p_opp))
>>> +           return 0;
>>> +
>>> +   opp = dev_pm_opp_xlate_required_opp(cpu_state->opp_table,
>>> +                                       devfreq->opp_table, p_opp);
>>> +   dev_pm_opp_put(p_opp);
>>> +
>>> +   if (!IS_ERR(opp)) {
>>> +           freq = dev_pm_opp_get_freq(opp);
>>> +           dev_pm_opp_put(opp);
>>> +           goto out;
>>> +   }
>>> +
>>> +   /* Use Interpolation if required opps is not available */
>>> +   cpu_min_freq = cpu_state->min_freq;
>>> +   cpu_max_freq = cpu_state->max_freq;
>>> +   cpu_curr_freq_khz = cpu_state->curr_freq;
>>> +
>>> +   if (dev_freq_table) {
>>> +           /* Get minimum frequency according to sorting order */
>>> +           dev_max_state = dev_freq_table[devfreq->profile->max_state - 1];
>>> +           if (dev_freq_table[0] < dev_max_state) {
>>> +                   dev_min_freq = dev_freq_table[0];
>>> +                   dev_max_freq = dev_max_state;
>>> +           } else {
>>> +                   dev_min_freq = dev_max_state;
>>> +                   dev_max_freq = dev_freq_table[0];
>>> +           }
>>> +   } else {
>>> +           dev_min_freq = dev_pm_qos_read_value(devfreq->dev.parent,
>>> +                                                DEV_PM_QOS_MIN_FREQUENCY);
>>> +           dev_max_freq = dev_pm_qos_read_value(devfreq->dev.parent,
>>> +                                                DEV_PM_QOS_MAX_FREQUENCY);
>>> +
>>> +           if (dev_max_freq <= dev_min_freq)
>>> +                   return 0;
>>> +   }
>>> +   cpu_percent = ((cpu_curr_freq_khz - cpu_min_freq) * 100) / cpu_max_freq 
>>> - cpu_min_freq;
>>> +   freq = dev_min_freq + mult_frac(dev_max_freq - dev_min_freq, 
>>> cpu_percent, 100);
>>> +
>>> +out:
>>> +   return freq;
>>> +}
>>> +
>>> +static int get_target_freq_with_cpufreq(struct devfreq *devfreq,
>>> +                                   unsigned long *freq)
>>> +{
>>> +   struct devfreq_passive_data *p_data =
>>> +                           (struct devfreq_passive_data *)devfreq->data;
>>> +   unsigned int cpu;
>>> +   unsigned long target_freq = 0;
>>> +
>>> +   for_each_online_cpu(cpu)
>>> +           target_freq = max(target_freq,
>>> +                             xlate_cpufreq_to_devfreq(p_data, cpu));
>>> +
>>> +   *freq = target_freq;
>>> +
>>> +   return 0;
>>> +}
>>
>> As you knew, governor_passive.c was already used 
>> both 'dev_pm_opp_xlate_required_opp' and 'devfreq_recommended_opp'
>> to get the target from OPP. So, I wan to make the common function
>> like 'get_taget_freq_by_required_opp' as following:
>> If define 'get_taget_freq_by_required_opp' as following,
>> it will be used for get_target_freq_with_devfreq().
>> After finisied the review of this patch, I'll send the patch[2].
>> [2] 
>> https://urldefense.com/v3/__https://git.kernel.org/pub/scm/linux/kernel/git/chanwoo/linux.git/commit/?h=devfreq-testing-passive-gov&id=101c5a087586ab2b5cf3370166a7e39227ca83cf__;!!CTRNKA9wMg0ARbw!zIrzeDp9vPnm1_SDzVPuzqdHn3zWie9DnfBXaA-j9-CSrVc6aR9_rJQQiw81_CgA6mp3Yqo$
>>  
>>
>> For example but this code is not tested,
>> static unsigned long get_taget_freq_by_required_opp(struct device *p_dev,
>>                                              struct opp_table *p_opp_table,
>>                                              struct opp_table *opp_table,
>>                                              unsigned long freq)
>> {
>>      struct dev_pm_opp *opp = NULL, *p_opp = NULL;
>>
>>      if (!p_dev || !p_opp_table || !opp_table || !freq)
>>              return 0;
>>
>>      p_opp = devfreq_recommended_opp(p_dev, &freq, 0);
>>      if (IS_ERR(p_opp))
>>              return 0;
>>
>>      opp = dev_pm_opp_xlate_required_opp(p_opp_table, opp_table, p_opp);
>>      dev_pm_opp_put(p_opp);
>>
>>      if (IS_ERR(opp))
>>              return 0;
>>
>>      freq = dev_pm_opp_get_freq(opp);
>>      dev_pm_opp_put(opp);
>>
>>      return freq;
>> }
>>
>> static int get_target_freq_with_cpufreq(struct devfreq *devfreq,
>>                                      unsigned long *target_freq)
>> {
>>      struct devfreq_passive_data *p_data =
>>                              (struct devfreq_passive_data *)devfreq->data;
>>      struct devfreq_cpu_data *cpu_data;
>>      unsigned long cpu, cpu_cur, cpu_min, cpu_max, cpu_percent;
>>      unsigned long dev_min, dev_max;
>>      unsigned long freq = 0;
>>
>>      for_each_online_cpu(cpu) {
>>              cpu_data = p_data->cpu_data[cpu];
>>              if (!cpu_data || cpu_data->first_cpu != cpu)
>>                      continue;
>>
>>              /* Get target freq via required opps */
>>              cpu_cur = cpu_data->cur_freq * HZ_PER_KHZ;
>>              freq = get_taget_freq_by_required_opp(cpu_data->dev,
>>                                      cpu_data->opp_table,
>>                                      devfreq->opp_table, cpu_cur);
>>              if (freq) {
>>                      *target_freq = max(freq, *target_freq);
>>                      continue;
>>              }
>>
>>              /* Use Interpolation if required opps is not available */
>>              devfreq_get_freq_range(devfreq, &dev_min, &dev_max);
>>
>>              cpu_min = cpu_data->min_freq;
>>              cpu_max = cpu_data->max_freq;
>>              cpu_cur = cpu_data->cur_freq;
>>
>>              cpu_percent = ((cpu_cur - cpu_min) * 100) / cpu_max - cpu_min;
>>              freq = dev_min + mult_frac(dev_max - dev_min, cpu_percent, 100);
>>
>>              *target_freq = max(freq, *target_freq);
>>      }
>>
>>      return 0;
>> }
>>
>>> +
>>> +static int get_target_freq_with_devfreq(struct devfreq *devfreq,
>>>                                     unsigned long *freq)
>>>  {
>>>     struct devfreq_passive_data *p_data
>>> @@ -23,14 +115,6 @@ static int devfreq_passive_get_target_freq(struct 
>>> devfreq *devfreq,
>>>     int i, count;
>>>  
>>>     /*
>>> -    * If the devfreq device with passive governor has the specific method
>>> -    * to determine the next frequency, should use the get_target_freq()
>>> -    * of struct devfreq_passive_data.
>>> -    */
>>> -   if (p_data->get_target_freq)
>>> -           return p_data->get_target_freq(devfreq, freq);
>>> -
>>> -   /*
>>>      * If the parent and passive devfreq device uses the OPP table,
>>>      * get the next frequency by using the OPP table.
>>>      */
>>> @@ -98,6 +182,37 @@ static int devfreq_passive_get_target_freq(struct 
>>> devfreq *devfreq,
>>>     return 0;
>>>  }
>>>  
>>> +static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>> +                                      unsigned long *freq)
>>> +{
>>> +   struct devfreq_passive_data *p_data =
>>> +           (struct devfreq_passive_data *)devfreq->data;
>>> +   int ret;
>>> +
>>> +   /*
>>> +    * If the devfreq device with passive governor has the specific method
>>> +    * to determine the next frequency, should use the get_target_freq()
>>> +    * of struct devfreq_passive_data.
>>> +    */
>>> +   if (p_data->get_target_freq)
>>> +           return p_data->get_target_freq(devfreq, freq);
>>> +
>>> +   switch (p_data->parent_type) {
>>> +   case DEVFREQ_PARENT_DEV:
>>> +           ret = get_target_freq_with_devfreq(devfreq, freq);
>>> +           break;
>>> +   case CPUFREQ_PARENT_DEV:
>>> +           ret = get_target_freq_with_cpufreq(devfreq, freq);
>>> +           break;
>>> +   default:
>>> +           ret = -EINVAL;
>>> +           dev_err(&devfreq->dev, "Invalid parent type\n");
>>> +           break;
>>> +   }
>>> +
>>> +   return ret;
>>> +}
>>> +
>>>  static int devfreq_passive_notifier_call(struct notifier_block *nb,
>>>                             unsigned long event, void *ptr)
>>>  {
>>> @@ -130,16 +245,200 @@ static int devfreq_passive_notifier_call(struct 
>>> notifier_block *nb,
>>>     return NOTIFY_DONE;
>>>  }
>>>  
>>> +static int cpufreq_passive_notifier_call(struct notifier_block *nb,
>>> +                                    unsigned long event, void *ptr)
>>> +{
>>> +   struct devfreq_passive_data *data =
>>> +                   container_of(nb, struct devfreq_passive_data, nb);
>>> +   struct devfreq *devfreq = (struct devfreq *)data->this;
>>> +   struct devfreq_cpu_state *cpu_state;
>>> +   struct cpufreq_freqs *cpu_freq = ptr;
>>
>> Use 'freqs' variable name.  I prefer to use the same variable name
>> for both devfreq_freqs and cpufreq_freqs instance.
>>
>>> +   unsigned int curr_freq;
>>
>> As I commented above, better to use 'cur_frq' instead of 'curr_freq'
>> if there is no any special reason.
>>
>>> +   int ret;
>>> +
>>> +   if (event != CPUFREQ_POSTCHANGE || !cpu_freq ||
>>> +       !data->cpu_state[cpu_freq->policy->cpu])
>>> +           return 0;
>>> +
>>> +   cpu_state = data->cpu_state[cpu_freq->policy->cpu];
>>> +   if (cpu_state->curr_freq == cpu_freq->new)
>>> +           return 0;
>>> +
>>> +   /* Backup current freq and pre-update cpu state freq*/
>>
>> I think that this commnet is not critial. So, please drop this comment.
>>
>>> +   curr_freq = cpu_state->curr_freq;
>>> +   cpu_state->curr_freq = cpu_freq->new;
>>> +
>>> +   mutex_lock(&devfreq->lock);
>>> +   ret = update_devfreq(devfreq);
>>
>> I recommend to use 'devfreq_update_target' instead of 'update_devfreq'
>> as following:
>>      devfreq_update_target(devfreq, freqs->new);
>>
>>> +   mutex_unlock(&devfreq->lock);
>>> +   if (ret) {
>>> +           cpu_state->curr_freq = curr_freq;
>>> +           dev_err(&devfreq->dev, "Couldn't update the frequency.\n");
>>> +           return ret;
>>> +   }
>>> +
>>> +   return 0;
>>> +}
>>> +
>>> +static int cpufreq_passive_register(struct devfreq_passive_data **p_data)
>>
>> In order to keep the consistent style of function name,
>> please change the name as following because devfreq defines
>> the function name as 'devfreq_regiter_notifier'
>> - cpufreq_passive_register -> cpufreq_passive_register_notifier
>>
>>> +{
>>> +   struct devfreq_passive_data *data = *p_data;
>>> +   struct devfreq *devfreq = (struct devfreq *)data->this;
>>> +   struct device *dev = devfreq->dev.parent;
>>> +   struct opp_table *opp_table = NULL;
>>> +   struct devfreq_cpu_state *cpu_state;
>>> +   struct cpufreq_policy *policy;
>>> +   struct device *cpu_dev;
>>> +   unsigned int cpu;
>>> +   int ret;
>>> +
>>> +   get_online_cpus();
>>> +
>>> +   data->nb.notifier_call = cpufreq_passive_notifier_call;
>>> +   ret = cpufreq_register_notifier(&data->nb,
>>> +                                   CPUFREQ_TRANSITION_NOTIFIER);
>>> +   if (ret) {
>>> +           dev_err(dev, "Couldn't register cpufreq notifier.\n");
>>> +           data->nb.notifier_call = NULL;
>>> +           goto out;
>>> +   }
>>> +
>>> +   /* Populate devfreq_cpu_state */
>>
>> Don't need this comment. Please drop it.
>>
>>> +   for_each_online_cpu(cpu) {
>>> +           if (data->cpu_state[cpu])
>>> +                   continue;
>>> +
>>> +           policy = cpufreq_cpu_get(cpu);
>>> +           if (!policy) {
>>> +                   ret = -EINVAL;
>>> +                   goto out;
>>> +           } else if (PTR_ERR(policy) == -EPROBE_DEFER) {
>>> +                   ret = -EPROBE_DEFER;
>>> +                   goto out;
>>> +           } else if (IS_ERR(policy)) {
>>> +                   ret = PTR_ERR(policy);
>>> +                   dev_err(dev, "Couldn't get the cpufreq_poliy.\n");
>>> +                   goto out;
>>> +           }
>>
>> Use dev_err_probe() funciotn to handle hte EPROBE_DEFER.
>> It make code more simple.
>>
>>> +
>>> +           cpu_state = kzalloc(sizeof(*cpu_state), GFP_KERNEL);
>>> +           if (!cpu_state) {
>>> +                   ret = -ENOMEM;
>>> +                   goto out;
>>> +           }
>>> +
>>> +           cpu_dev = get_cpu_device(cpu);
>>> +           if (!cpu_dev) {
>>> +                   dev_err(dev, "Couldn't get cpu device.\n");
>>> +                   ret = -ENODEV;
>>> +                   goto out;
>>> +           }
>>> +
>>> +           opp_table = dev_pm_opp_get_opp_table(cpu_dev);
>>> +           if (IS_ERR(devfreq->opp_table)) {
>>> +                   ret = PTR_ERR(opp_table);
>>> +                   goto out;
>>> +           }
>>> +
>>> +           cpu_state->cpu_dev = cpu_dev;
>>> +           cpu_state->opp_table = opp_table;
>>> +           cpu_state->first_cpu = cpumask_first(policy->related_cpus);
>>> +           cpu_state->curr_freq = policy->cur;
>>> +           cpu_state->min_freq = policy->cpuinfo.min_freq;
>>> +           cpu_state->max_freq = policy->cpuinfo.max_freq;
>>> +           data->cpu_state[cpu] = cpu_state;
>>> +
>>> +           cpufreq_cpu_put(policy);
>>> +   }
>>> +
>>> +out:
>>> +   put_online_cpus();
>>> +   if (ret)
>>> +           return ret;
>>> +
>>> +   /* Update devfreq */
>>> +   mutex_lock(&devfreq->lock);
>>> +   ret = update_devfreq(devfreq);
>>
>>> +   mutex_unlock(&devfreq->lock);
>>> +   if (ret)
>>> +           dev_err(dev, "Couldn't update the frequency.\n");
>>> +
>>> +   return ret;
>>> +}
>>> +
>>> +static int cpufreq_passive_unregister(struct devfreq_passive_data **p_data)
>>
>> As I commented above, please change the name as following:
>> - cpufreq_passive_unregister -> cpufreq_passive_unregister_notifier
>>
>>> +{
>>> +   struct devfreq_passive_data *data = *p_data;
>>> +   struct devfreq_cpu_state *cpu_state;
>>> +   int cpu;
>>> +
>>> +   if (data->nb.notifier_call)
>>> +           cpufreq_unregister_notifier(&data->nb,
>>> +                                       CPUFREQ_TRANSITION_NOTIFIER);
>>> +
>>> +   for_each_possible_cpu(cpu) {
>>> +           cpu_state = data->cpu_state[cpu];
>>> +           if (cpu_state) {
>>> +                   if (cpu_state->opp_table)
>>> +                           dev_pm_opp_put_opp_table(cpu_state->opp_table);
>>> +                   kfree(cpu_state);
>>> +                   cpu_state = NULL;
>>> +           }
>>> +   }
>>> +
>>> +   return 0;
>>> +}
>>> +
>>> +int register_parent_dev_notifier(struct devfreq_passive_data **p_data)
>>> +{
>>> +   struct notifier_block *nb = &(*p_data)->nb;
>>> +   int ret = 0;
>>> +
>>> +   switch ((*p_data)->parent_type) {
>>> +   case DEVFREQ_PARENT_DEV:
>>> +           nb->notifier_call = devfreq_passive_notifier_call;
>>> +           ret = devfreq_register_notifier((struct devfreq 
>>> *)(*p_data)->parent, nb,
>>> +                                           DEVFREQ_TRANSITION_NOTIFIER);
>>> +           break;
>>> +   case CPUFREQ_PARENT_DEV:
>>> +           ret = cpufreq_passive_register(p_data);
>>> +           break;
>>> +   default:
>>> +           ret = -EINVAL;
>>> +           break;
>>> +   }
>>> +   return ret;
>>> +}
>>> +
>>> +int unregister_parent_dev_notifier(struct devfreq_passive_data **p_data)
>>> +{
>>> +   int ret = 0;
>>> +
>>> +   switch ((*p_data)->parent_type) {
>>> +   case DEVFREQ_PARENT_DEV:
>>> +           WARN_ON(devfreq_unregister_notifier((struct devfreq 
>>> *)(*p_data)->parent,
>>> +                                               &(*p_data)->nb,
>>> +                                               
>>> DEVFREQ_TRANSITION_NOTIFIER));
>>> +           break;
>>> +   case CPUFREQ_PARENT_DEV:
>>> +           cpufreq_passive_unregister(p_data);
>>> +           break;
>>> +   default:
>>> +           ret = -EINVAL;
>>> +           break;
>>> +   }
>>> +   return ret;
>>> +}
>>
>> I think that you don't need to define register_parent_dev_notifier
>> and unregister_parent_dev_notifier as the separate functions.
>>
>> Instead of the separate functions, just add the code
>> into devfreq_passive_event_handler.
>>
>>
>>> +
>>>  static int devfreq_passive_event_handler(struct devfreq *devfreq,
>>>                             unsigned int event, void *data)
>>>  {
>>>     struct devfreq_passive_data *p_data
>>>                     = (struct devfreq_passive_data *)devfreq->data;
>>>     struct devfreq *parent = (struct devfreq *)p_data->parent;
>>> -   struct notifier_block *nb = &p_data->nb;
>>>     int ret = 0;
>>>  
>>> -   if (!parent)
>>> +   if (p_data->parent_type == DEVFREQ_PARENT_DEV && !parent)
>>>             return -EPROBE_DEFER;
>>>  
>>>     switch (event) {
>>> @@ -147,13 +446,11 @@ static int devfreq_passive_event_handler(struct 
>>> devfreq *devfreq,
>>>             if (!p_data->this)
>>>                     p_data->this = devfreq;
>>>  
>>> -           nb->notifier_call = devfreq_passive_notifier_call;
>>> -           ret = devfreq_register_notifier(parent, nb,
>>> -                                   DEVFREQ_TRANSITION_NOTIFIER);
>>> +           ret = register_parent_dev_notifier(&p_data);
>>>             break;
>>> +
>>>     case DEVFREQ_GOV_STOP:
>>> -           WARN_ON(devfreq_unregister_notifier(parent, nb,
>>> -                                   DEVFREQ_TRANSITION_NOTIFIER));
>>> +           ret = unregister_parent_dev_notifier(&p_data);
>>>             break;
>>>     default:
>>>             break;
>>> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
>>> index 26ea0850be9b..e0093b7c805c 100644
>>> --- a/include/linux/devfreq.h
>>> +++ b/include/linux/devfreq.h
>>> @@ -280,6 +280,25 @@ struct devfreq_simple_ondemand_data {
>>>  
>>>  #if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE)
>>>  /**
>>> + * struct devfreq_cpu_state - holds the per-cpu state
>>> + * @freq:  the current frequency of the cpu.
>>> + * @min_freq:      the min frequency of the cpu.
>>> + * @max_freq:      the max frequency of the cpu.
>>> + * @first_cpu:     the cpumask of the first cpu of a policy.
>>> + * @dev:   reference to cpu device.
>>> + * @opp_table:     reference to cpu opp table.
>>> + *
>>> + * This structure stores the required cpu_state of a cpu.
>>> + * This is auto-populated by the governor.
>>> + */
>>> +struct devfreq_cpu_state;
>>> +
>>> +enum devfreq_parent_dev_type {
>>> +   DEVFREQ_PARENT_DEV,
>>> +   CPUFREQ_PARENT_DEV,
>>> +};
>>> +
>>> +/**
>>>   * struct devfreq_passive_data - ``void *data`` fed to struct devfreq
>>>   * and devfreq_add_device
>>>   * @parent:        the devfreq instance of parent device.
>>> @@ -290,13 +309,15 @@ struct devfreq_simple_ondemand_data {
>>>   *                 using governors except for passive governor.
>>>   *                 If the devfreq device has the specific method to decide
>>>   *                 the next frequency, should use this callback.
>>> + * @parent_type:   parent type of the device
>>>   * @this:  the devfreq instance of own device.
>>>   * @nb:            the notifier block for DEVFREQ_TRANSITION_NOTIFIER list
>>> + * @cpu_state:             the state min/max/current frequency of all 
>>> online cpu's
>>>   *
>>>   * The devfreq_passive_data have to set the devfreq instance of parent
>>>   * device with governors except for the passive governor. But, don't need 
>>> to
>>> - * initialize the 'this' and 'nb' field because the devfreq core will 
>>> handle
>>> - * them.
>>> + * initialize the 'this', 'nb' and 'cpu_state' field because the devfreq 
>>> core
>>> + * will handle them.
>>>   */
>>>  struct devfreq_passive_data {
>>>     /* Should set the devfreq instance of parent device */
>>> @@ -305,9 +326,13 @@ struct devfreq_passive_data {
>>>     /* Optional callback to decide the next frequency of passvice device */
>>>     int (*get_target_freq)(struct devfreq *this, unsigned long *freq);
>>>  
>>> +   /* Should set the type of parent device */
>>> +   enum devfreq_parent_dev_type parent_type;
>>> +
>>>     /* For passive governor's internal use. Don't need to set them */
>>>     struct devfreq *this;
>>>     struct notifier_block nb;
>>> +   struct devfreq_cpu_state *cpu_state[NR_CPUS];
>>>  };
>>>  #endif
>>>  
>>>
>>
> 


-- 
Best Regards,
Chanwoo Choi
Samsung Electronics

Reply via email to