[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
> >>>>
> >>>>
> >>>
> >>
> >
> >
>
>
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