[PATCH V8 1/8] PM / devfreq: Add cpu based scaling support to passive_governor

andrew-sh.cheng andrew-sh.cheng at mediatek.com
Wed Mar 31 14:03:20 BST 2021


On Wed, 2021-03-31 at 17:35 +0900, Chanwoo Choi wrote:
> On 3/31/21 5:27 PM, Chanwoo Choi wrote:
> > 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 <skannan at codeaurora.org>' 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://urldefense.com/v3/__https://git.kernel.org/pub/scm/linux/kernel/git/chanwoo/linux.git/log/?h=devfreq-testing-passive-gov__;!!CTRNKA9wMg0ARbw!yUlsuxrL5PcbF7o6A9DlCfvoA6w8V8VXKjYIybYyiJg3D0HM-lI2xRuxLUV6b3UJ8WFhg_g$ 
> > 
> > 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://urldefense.com/v3/__https://git.kernel.org/pub/scm/linux/kernel/git/chanwoo/linux.git/commit/?h=devfreq-testing-passive-gov&id=39c80d11a8f42dd63ecea1e0df595a0ceb83b454__;!!CTRNKA9wMg0ARbw!yUlsuxrL5PcbF7o6A9DlCfvoA6w8V8VXKjYIybYyiJg3D0HM-lI2xRuxLUV6b3UJR2cQqZs$ 
> 
> 
> Sorry for the confusion. I make the devfreq-testing-passive-gov[1]
> branch based on latest devfreq-next branch.
> [1] https://urldefense.com/v3/__https://git.kernel.org/pub/scm/linux/kernel/git/chanwoo/linux.git/log/?h=devfreq-testing-passive-gov__;!!CTRNKA9wMg0ARbw!yUlsuxrL5PcbF7o6A9DlCfvoA6w8V8VXKjYIybYyiJg3D0HM-lI2xRuxLUV6b3UJ8WFhg_g$ 
> 
> First of all, if possible, I want to test them[1] with your patches in this series.
> And then if there are no any problem, please let me know. After confirmed from you,
> I'll send the patches of devfreq-testing-passive-gov[1] branch.
> How about that?
> 
Hi Chanwoo~

We will use this on Google Chrome project.
Google Hsin-Yi has test your patch + my patch set v8 [2~8]

    make sure cci devfreqs runs with cpufreq.
    suspend resume
    speedometer2 benchmark
It is okay.

Please send the patches of devfreq-testing-passive-gov[1] branch.

I will send patch v9 base on yours latter.


> 
> > 
> >>
> >>
> >>>
> >>>
> >>> On 3/23/21 8:33 PM, Andrew-sh.Cheng wrote:
> >>>> From: Saravana Kannan <skannan at codeaurora.org>
> >>>>
> >>>> 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 <skannan at codeaurora.org>
> >>>> [Sibi: Integrated cpu-freqmap governor into passive_governor]
> >>>> Signed-off-by: Sibi Sankar <sibis at codeaurora.org>
> >>>> Signed-off-by: Andrew-sh.Cheng <andrew-sh.cheng at mediatek.com>
> >>>> ---
> >>>>  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
> >>>>  
> >>>>
> >>>
> >>
> > 
> > 
> 
> 



More information about the linux-arm-kernel mailing list