| Message ID | 1479909087-22659-2-git-send-email-tjakobi@math.uni-bielefeld.de (mailing list archive) |
|---|---|
| State | RFC, archived |
| Headers | show |
Hi Tobias, I like your suggestion. But I have some comment on below. On 2016년 11월 23일 22:51, Tobias Jakobi wrote: > This suspend/resume operations works analogous to the > cpufreq_{suspend,resume}() calls in the CPUFreq subsystem. > > Signed-off-by: Tobias Jakobi <tjakobi@math.uni-bielefeld.de> > --- > drivers/devfreq/devfreq.c | 75 +++++++++++++++++++++++++++++++++++++++++++++++ > include/linux/devfreq.h | 10 +++++++ > 2 files changed, 85 insertions(+) > > diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c > index bf3ea76..2f1aa83 100644 > --- a/drivers/devfreq/devfreq.c > +++ b/drivers/devfreq/devfreq.c > @@ -785,6 +785,81 @@ int devfreq_resume_device(struct devfreq *devfreq) > EXPORT_SYMBOL(devfreq_resume_device); > > /** > + * devfreq_suspend() - Suspend DevFreq governors > + * > + * Called during system wide Suspend/Hibernate cycles for suspending governors > + * in the same fashion as cpufreq_suspend(). > + */ > +void devfreq_suspend(void) > +{ > + struct devfreq *devfreq; > + unsigned long freq; > + int ret; > + > + mutex_lock(&devfreq_list_lock); > + > + list_for_each_entry(devfreq, &devfreq_list, node) { > + if (!devfreq->suspend_freq) > + continue; > + > + ret = devfreq_suspend_device(devfreq); > + if (ret < 0) { > + dev_warn(&devfreq->dev, "%s: governor suspend failed\n", __func__); > + continue; > + } > + > + devfreq->resume_freq = 0; > + if (devfreq->profile->get_cur_freq) { > + ret = devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq); > + if (ret >= 0) > + devfreq->resume_freq = freq; > + } > + > + freq = devfreq->suspend_freq; > + ret = devfreq->profile->target(devfreq->dev.parent, &freq, 0); DEVFREQ subsystem has the passive governor[2] and devfreq device using passive[1] governor depends on the parent devfreq device. The passive governor uses 'DEVFREQ_TRANSITION_NOTIFIER' notifier to track the changed state of parent devfreq device. When changing the clock/voltage of parent devfreq device, DEVFREQ subsystem have to notify the changed frequency to the passive devfreq device. So, you should call the devfreq_notifiy_transition() before/after 'devfreq->profile->target' as following: You can refer the update_devfreq() function that is how to use devfreq_notifiy_transition(). For example, struct devfreq_freq freqs; if (devfreq->profile->get_cur_freq) { ret = devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq); if (ret >= 0) devfreq->resume_freq = freq; } else { devfreq->resume_freq = devfreq_previous_freq; } freqs.old = devfreq->resume_freq; freqs.new = devfreq->suspend_freq; devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE); freq = devfreq->suspend_freq; ret = devfreq->profile->target(devfreq->dev.parent, &freq, 0); freqs.new = freq; devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE); if (ret < 0) dev_warn(&devfreq->dev, "%s: setting suspend frequency failed\n", __func__); } [1] DEVFREQ_TRANSITION_NOTIFIER notifier - https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=0fe3a66410a3ba96679be903f1e287d7a0a264a9 [2] DEVFREQ passive governor - https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=996133119f57334c38b020dbfaaac5b5eb127e29 > + > + if (ret < 0) > + dev_warn(&devfreq->dev, "%s: setting suspend frequency failed\n", __func__); > + } > + > + mutex_unlock(&devfreq_list_lock); > +} > + > +/** > + * devfreq_resume() - Resume DevFreq governors > + * > + * Called during system wide Suspend/Hibernate cycle for resuming governors that > + * are suspended with devfreq_suspend(). > + */ > +void devfreq_resume(void) > +{ > + struct devfreq *devfreq; > + unsigned long freq; > + int ret; > + > + mutex_lock(&devfreq_list_lock); > + > + list_for_each_entry(devfreq, &devfreq_list, node) { > + if (!devfreq->suspend_freq) > + continue; > + > + freq = devfreq->resume_freq; > + ret = devfreq->profile->target(devfreq->dev.parent, &freq, 0); ditto. > + > + if (ret < 0) { > + dev_warn(&devfreq->dev, "%s: setting resume frequency failed\n", __func__); > + continue; > + } > + > + ret = devfreq_resume_device(devfreq); > + if (ret < 0) > + dev_warn(&devfreq->dev, "%s: governor resume failed\n", __func__); > + } > + > + mutex_unlock(&devfreq_list_lock); > +} > + > +/** > * devfreq_add_governor() - Add devfreq governor > * @governor: the devfreq governor to be added > */ > diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h > index 2de4e2e..555d024 100644 > --- a/include/linux/devfreq.h > +++ b/include/linux/devfreq.h > @@ -171,6 +171,9 @@ struct devfreq { > struct notifier_block nb; > struct delayed_work work; > > + unsigned long suspend_freq; /* freq during devfreq suspend */ > + unsigned long resume_freq; /* freq restored after suspend cycle */ > + > unsigned long previous_freq; > struct devfreq_dev_status last_status; > > @@ -211,6 +214,10 @@ extern void devm_devfreq_remove_device(struct device *dev, > extern int devfreq_suspend_device(struct devfreq *devfreq); > extern int devfreq_resume_device(struct devfreq *devfreq); > > +/* Suspend/resume the entire Devfreq subsystem. */ > +void devfreq_suspend(void); > +void devfreq_resume(void); > + > /* Helper functions for devfreq user device driver with OPP. */ > extern struct dev_pm_opp *devfreq_recommended_opp(struct device *dev, > unsigned long *freq, u32 flags); > @@ -410,6 +417,9 @@ static inline int devfreq_update_stats(struct devfreq *df) > { > return -EINVAL; > } > + > +static inline void devfreq_suspend(void) {} > +static inline void devfreq_resume(void) {} > #endif /* CONFIG_PM_DEVFREQ */ > > #endif /* __LINUX_DEVFREQ_H__ */ >
Hi Tobias, On 2016년 11월 24일 10:34, Chanwoo Choi wrote: > Hi Tobias, > > I like your suggestion. But I have some comment on below. > > On 2016년 11월 23일 22:51, Tobias Jakobi wrote: >> This suspend/resume operations works analogous to the >> cpufreq_{suspend,resume}() calls in the CPUFreq subsystem. >> >> Signed-off-by: Tobias Jakobi <tjakobi@math.uni-bielefeld.de> >> --- >> drivers/devfreq/devfreq.c | 75 +++++++++++++++++++++++++++++++++++++++++++++++ >> include/linux/devfreq.h | 10 +++++++ >> 2 files changed, 85 insertions(+) >> >> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c >> index bf3ea76..2f1aa83 100644 >> --- a/drivers/devfreq/devfreq.c >> +++ b/drivers/devfreq/devfreq.c >> @@ -785,6 +785,81 @@ int devfreq_resume_device(struct devfreq *devfreq) >> EXPORT_SYMBOL(devfreq_resume_device); >> >> /** >> + * devfreq_suspend() - Suspend DevFreq governors >> + * >> + * Called during system wide Suspend/Hibernate cycles for suspending governors >> + * in the same fashion as cpufreq_suspend(). >> + */ >> +void devfreq_suspend(void) >> +{ >> + struct devfreq *devfreq; >> + unsigned long freq; >> + int ret; >> + >> + mutex_lock(&devfreq_list_lock); >> + >> + list_for_each_entry(devfreq, &devfreq_list, node) { >> + if (!devfreq->suspend_freq) >> + continue; >> + >> + ret = devfreq_suspend_device(devfreq); The devfreq_suspend_device() stop the monitoring of governors. But, this function is exported. It means that each devfreq device. can call the devfreq_suspend/resume_device() (e.g., int drivers/scsi/ufs/ufshcd.c) So, you should consider following case: - case :Before calling the devfreq_suspend() and specific devfreq already call the devfreq_suspend_device(), how to support it? In this case, the specific devfreq device don't want to call the devfreq_resume_device() in the devfreq_resume(). >> + if (ret < 0) { >> + dev_warn(&devfreq->dev, "%s: governor suspend failed\n", __func__); >> + continue; >> + } >> + >> + devfreq->resume_freq = 0; >> + if (devfreq->profile->get_cur_freq) { >> + ret = devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq); >> + if (ret >= 0) >> + devfreq->resume_freq = freq; >> + } >> + >> + freq = devfreq->suspend_freq; >> + ret = devfreq->profile->target(devfreq->dev.parent, &freq, 0); > > > DEVFREQ subsystem has the passive governor[2] and devfreq device using passive[1] > governor depends on the parent devfreq device. The passive governor uses > 'DEVFREQ_TRANSITION_NOTIFIER' notifier to track the changed state of > parent devfreq device. > > When changing the clock/voltage of parent devfreq device, > DEVFREQ subsystem have to notify the changed frequency > to the passive devfreq device. > > So, you should call the devfreq_notifiy_transition() > before/after 'devfreq->profile->target' as following: > You can refer the update_devfreq() function > that is how to use devfreq_notifiy_transition(). > > For example, > struct devfreq_freq freqs; > > if (devfreq->profile->get_cur_freq) { > ret = devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq); > if (ret >= 0) > devfreq->resume_freq = freq; > } else { > devfreq->resume_freq = devfreq_previous_freq; > } > > freqs.old = devfreq->resume_freq; > freqs.new = devfreq->suspend_freq; > devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE); > > freq = devfreq->suspend_freq; > ret = devfreq->profile->target(devfreq->dev.parent, &freq, 0); > > freqs.new = freq; > devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE); > > if (ret < 0) > dev_warn(&devfreq->dev, "%s: setting suspend frequency failed\n", __func__); > } > > [1] DEVFREQ_TRANSITION_NOTIFIER notifier > - https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=0fe3a66410a3ba96679be903f1e287d7a0a264a9 > [2] DEVFREQ passive governor > - https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=996133119f57334c38b020dbfaaac5b5eb127e29 > >> + >> + if (ret < 0) >> + dev_warn(&devfreq->dev, "%s: setting suspend frequency failed\n", __func__); >> + } >> + >> + mutex_unlock(&devfreq_list_lock); >> +} >> + >> +/** >> + * devfreq_resume() - Resume DevFreq governors >> + * >> + * Called during system wide Suspend/Hibernate cycle for resuming governors that >> + * are suspended with devfreq_suspend(). >> + */ >> +void devfreq_resume(void) >> +{ >> + struct devfreq *devfreq; >> + unsigned long freq; >> + int ret; >> + >> + mutex_lock(&devfreq_list_lock); >> + >> + list_for_each_entry(devfreq, &devfreq_list, node) { >> + if (!devfreq->suspend_freq) >> + continue; >> + >> + freq = devfreq->resume_freq; >> + ret = devfreq->profile->target(devfreq->dev.parent, &freq, 0); > > ditto. > >> + >> + if (ret < 0) { >> + dev_warn(&devfreq->dev, "%s: setting resume frequency failed\n", __func__); >> + continue; >> + } >> + >> + ret = devfreq_resume_device(devfreq); >> + if (ret < 0) >> + dev_warn(&devfreq->dev, "%s: governor resume failed\n", __func__); >> + } >> + >> + mutex_unlock(&devfreq_list_lock); >> +} >> + >> +/** >> * devfreq_add_governor() - Add devfreq governor >> * @governor: the devfreq governor to be added >> */ >> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h >> index 2de4e2e..555d024 100644 >> --- a/include/linux/devfreq.h >> +++ b/include/linux/devfreq.h >> @@ -171,6 +171,9 @@ struct devfreq { >> struct notifier_block nb; >> struct delayed_work work; >> >> + unsigned long suspend_freq; /* freq during devfreq suspend */ >> + unsigned long resume_freq; /* freq restored after suspend cycle */ >> + >> unsigned long previous_freq; >> struct devfreq_dev_status last_status; >> >> @@ -211,6 +214,10 @@ extern void devm_devfreq_remove_device(struct device *dev, >> extern int devfreq_suspend_device(struct devfreq *devfreq); >> extern int devfreq_resume_device(struct devfreq *devfreq); >> >> +/* Suspend/resume the entire Devfreq subsystem. */ >> +void devfreq_suspend(void); >> +void devfreq_resume(void); >> + >> /* Helper functions for devfreq user device driver with OPP. */ >> extern struct dev_pm_opp *devfreq_recommended_opp(struct device *dev, >> unsigned long *freq, u32 flags); >> @@ -410,6 +417,9 @@ static inline int devfreq_update_stats(struct devfreq *df) >> { >> return -EINVAL; >> } >> + >> +static inline void devfreq_suspend(void) {} >> +static inline void devfreq_resume(void) {} >> #endif /* CONFIG_PM_DEVFREQ */ >> >> #endif /* __LINUX_DEVFREQ_H__ */ >> > > Best Regards, Chanwoo Choi -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hey Chanwoo, first of all, thanks for the help! Chanwoo Choi wrote: > Hi Tobias, > > On 2016년 11월 24일 10:34, Chanwoo Choi wrote: >> Hi Tobias, >> >> I like your suggestion. But I have some comment on below. >> >> On 2016년 11월 23일 22:51, Tobias Jakobi wrote: >>> This suspend/resume operations works analogous to the >>> cpufreq_{suspend,resume}() calls in the CPUFreq subsystem. >>> >>> Signed-off-by: Tobias Jakobi <tjakobi@math.uni-bielefeld.de> >>> --- >>> drivers/devfreq/devfreq.c | 75 +++++++++++++++++++++++++++++++++++++++++++++++ >>> include/linux/devfreq.h | 10 +++++++ >>> 2 files changed, 85 insertions(+) >>> >>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c >>> index bf3ea76..2f1aa83 100644 >>> --- a/drivers/devfreq/devfreq.c >>> +++ b/drivers/devfreq/devfreq.c >>> @@ -785,6 +785,81 @@ int devfreq_resume_device(struct devfreq *devfreq) >>> EXPORT_SYMBOL(devfreq_resume_device); >>> >>> /** >>> + * devfreq_suspend() - Suspend DevFreq governors >>> + * >>> + * Called during system wide Suspend/Hibernate cycles for suspending governors >>> + * in the same fashion as cpufreq_suspend(). >>> + */ >>> +void devfreq_suspend(void) >>> +{ >>> + struct devfreq *devfreq; >>> + unsigned long freq; >>> + int ret; >>> + >>> + mutex_lock(&devfreq_list_lock); >>> + >>> + list_for_each_entry(devfreq, &devfreq_list, node) { >>> + if (!devfreq->suspend_freq) >>> + continue; >>> + >>> + ret = devfreq_suspend_device(devfreq); > > The devfreq_suspend_device() stop the monitoring of governors. > But, this function is exported. It means that each devfreq device. > can call the devfreq_suspend/resume_device() (e.g., int drivers/scsi/ufs/ufshcd.c) > > So, you should consider following case: > - case :Before calling the devfreq_suspend() and specific devfreq already call > the devfreq_suspend_device(), how to support it? > In this case, the specific devfreq device don't want to call > the devfreq_resume_device() in the devfreq_resume(). How about this idea? Introduce a boolean 'devfreq_suspended' (again similar to CPUFreq) and set it to true (atomically?) once we have entered devfreq_suspend(). At the end of devfreq_suspend() we set it to false again. We just need to check in devfreq_{suspend,resume}_device() for 'devfreq_suspended' and return some error code (-EBUSY maybe?) to the caller. Of course I would inline the devfreq->governor->event_handler() call into devfreq_{suspend,resume}() first. Does this look sane? Also, do you see any other exported calls which we might have to 'protect' during suspended state? With best wishes, Tobias >>> + if (ret < 0) { >>> + dev_warn(&devfreq->dev, "%s: governor suspend failed\n", __func__); >>> + continue; >>> + } >>> + >>> + devfreq->resume_freq = 0; >>> + if (devfreq->profile->get_cur_freq) { >>> + ret = devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq); >>> + if (ret >= 0) >>> + devfreq->resume_freq = freq; >>> + } >>> + >>> + freq = devfreq->suspend_freq; >>> + ret = devfreq->profile->target(devfreq->dev.parent, &freq, 0); >> >> >> DEVFREQ subsystem has the passive governor[2] and devfreq device using passive[1] >> governor depends on the parent devfreq device. The passive governor uses >> 'DEVFREQ_TRANSITION_NOTIFIER' notifier to track the changed state of >> parent devfreq device. >> >> When changing the clock/voltage of parent devfreq device, >> DEVFREQ subsystem have to notify the changed frequency >> to the passive devfreq device. >> >> So, you should call the devfreq_notifiy_transition() >> before/after 'devfreq->profile->target' as following: >> You can refer the update_devfreq() function >> that is how to use devfreq_notifiy_transition(). >> >> For example, >> struct devfreq_freq freqs; >> >> if (devfreq->profile->get_cur_freq) { >> ret = devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq); >> if (ret >= 0) >> devfreq->resume_freq = freq; >> } else { >> devfreq->resume_freq = devfreq_previous_freq; >> } >> >> freqs.old = devfreq->resume_freq; >> freqs.new = devfreq->suspend_freq; >> devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE); >> >> freq = devfreq->suspend_freq; >> ret = devfreq->profile->target(devfreq->dev.parent, &freq, 0); >> >> freqs.new = freq; >> devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE); >> >> if (ret < 0) >> dev_warn(&devfreq->dev, "%s: setting suspend frequency failed\n", __func__); >> } >> >> [1] DEVFREQ_TRANSITION_NOTIFIER notifier >> - https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=0fe3a66410a3ba96679be903f1e287d7a0a264a9 >> [2] DEVFREQ passive governor >> - https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=996133119f57334c38b020dbfaaac5b5eb127e29 >> >>> + >>> + if (ret < 0) >>> + dev_warn(&devfreq->dev, "%s: setting suspend frequency failed\n", __func__); >>> + } >>> + >>> + mutex_unlock(&devfreq_list_lock); >>> +} >>> + >>> +/** >>> + * devfreq_resume() - Resume DevFreq governors >>> + * >>> + * Called during system wide Suspend/Hibernate cycle for resuming governors that >>> + * are suspended with devfreq_suspend(). >>> + */ >>> +void devfreq_resume(void) >>> +{ >>> + struct devfreq *devfreq; >>> + unsigned long freq; >>> + int ret; >>> + >>> + mutex_lock(&devfreq_list_lock); >>> + >>> + list_for_each_entry(devfreq, &devfreq_list, node) { >>> + if (!devfreq->suspend_freq) >>> + continue; >>> + >>> + freq = devfreq->resume_freq; >>> + ret = devfreq->profile->target(devfreq->dev.parent, &freq, 0); >> >> ditto. >> >>> + >>> + if (ret < 0) { >>> + dev_warn(&devfreq->dev, "%s: setting resume frequency failed\n", __func__); >>> + continue; >>> + } >>> + >>> + ret = devfreq_resume_device(devfreq); >>> + if (ret < 0) >>> + dev_warn(&devfreq->dev, "%s: governor resume failed\n", __func__); >>> + } >>> + >>> + mutex_unlock(&devfreq_list_lock); >>> +} >>> + >>> +/** >>> * devfreq_add_governor() - Add devfreq governor >>> * @governor: the devfreq governor to be added >>> */ >>> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h >>> index 2de4e2e..555d024 100644 >>> --- a/include/linux/devfreq.h >>> +++ b/include/linux/devfreq.h >>> @@ -171,6 +171,9 @@ struct devfreq { >>> struct notifier_block nb; >>> struct delayed_work work; >>> >>> + unsigned long suspend_freq; /* freq during devfreq suspend */ >>> + unsigned long resume_freq; /* freq restored after suspend cycle */ >>> + >>> unsigned long previous_freq; >>> struct devfreq_dev_status last_status; >>> >>> @@ -211,6 +214,10 @@ extern void devm_devfreq_remove_device(struct device *dev, >>> extern int devfreq_suspend_device(struct devfreq *devfreq); >>> extern int devfreq_resume_device(struct devfreq *devfreq); >>> >>> +/* Suspend/resume the entire Devfreq subsystem. */ >>> +void devfreq_suspend(void); >>> +void devfreq_resume(void); >>> + >>> /* Helper functions for devfreq user device driver with OPP. */ >>> extern struct dev_pm_opp *devfreq_recommended_opp(struct device *dev, >>> unsigned long *freq, u32 flags); >>> @@ -410,6 +417,9 @@ static inline int devfreq_update_stats(struct devfreq *df) >>> { >>> return -EINVAL; >>> } >>> + >>> +static inline void devfreq_suspend(void) {} >>> +static inline void devfreq_resume(void) {} >>> #endif /* CONFIG_PM_DEVFREQ */ >>> >>> #endif /* __LINUX_DEVFREQ_H__ */ >>> >> >> > Best Regards, > Chanwoo Choi > -- > To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c index bf3ea76..2f1aa83 100644 --- a/drivers/devfreq/devfreq.c +++ b/drivers/devfreq/devfreq.c @@ -785,6 +785,81 @@ int devfreq_resume_device(struct devfreq *devfreq) EXPORT_SYMBOL(devfreq_resume_device); /** + * devfreq_suspend() - Suspend DevFreq governors + * + * Called during system wide Suspend/Hibernate cycles for suspending governors + * in the same fashion as cpufreq_suspend(). + */ +void devfreq_suspend(void) +{ + struct devfreq *devfreq; + unsigned long freq; + int ret; + + mutex_lock(&devfreq_list_lock); + + list_for_each_entry(devfreq, &devfreq_list, node) { + if (!devfreq->suspend_freq) + continue; + + ret = devfreq_suspend_device(devfreq); + if (ret < 0) { + dev_warn(&devfreq->dev, "%s: governor suspend failed\n", __func__); + continue; + } + + devfreq->resume_freq = 0; + if (devfreq->profile->get_cur_freq) { + ret = devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq); + if (ret >= 0) + devfreq->resume_freq = freq; + } + + freq = devfreq->suspend_freq; + ret = devfreq->profile->target(devfreq->dev.parent, &freq, 0); + + if (ret < 0) + dev_warn(&devfreq->dev, "%s: setting suspend frequency failed\n", __func__); + } + + mutex_unlock(&devfreq_list_lock); +} + +/** + * devfreq_resume() - Resume DevFreq governors + * + * Called during system wide Suspend/Hibernate cycle for resuming governors that + * are suspended with devfreq_suspend(). + */ +void devfreq_resume(void) +{ + struct devfreq *devfreq; + unsigned long freq; + int ret; + + mutex_lock(&devfreq_list_lock); + + list_for_each_entry(devfreq, &devfreq_list, node) { + if (!devfreq->suspend_freq) + continue; + + freq = devfreq->resume_freq; + ret = devfreq->profile->target(devfreq->dev.parent, &freq, 0); + + if (ret < 0) { + dev_warn(&devfreq->dev, "%s: setting resume frequency failed\n", __func__); + continue; + } + + ret = devfreq_resume_device(devfreq); + if (ret < 0) + dev_warn(&devfreq->dev, "%s: governor resume failed\n", __func__); + } + + mutex_unlock(&devfreq_list_lock); +} + +/** * devfreq_add_governor() - Add devfreq governor * @governor: the devfreq governor to be added */ diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h index 2de4e2e..555d024 100644 --- a/include/linux/devfreq.h +++ b/include/linux/devfreq.h @@ -171,6 +171,9 @@ struct devfreq { struct notifier_block nb; struct delayed_work work; + unsigned long suspend_freq; /* freq during devfreq suspend */ + unsigned long resume_freq; /* freq restored after suspend cycle */ + unsigned long previous_freq; struct devfreq_dev_status last_status; @@ -211,6 +214,10 @@ extern void devm_devfreq_remove_device(struct device *dev, extern int devfreq_suspend_device(struct devfreq *devfreq); extern int devfreq_resume_device(struct devfreq *devfreq); +/* Suspend/resume the entire Devfreq subsystem. */ +void devfreq_suspend(void); +void devfreq_resume(void); + /* Helper functions for devfreq user device driver with OPP. */ extern struct dev_pm_opp *devfreq_recommended_opp(struct device *dev, unsigned long *freq, u32 flags); @@ -410,6 +417,9 @@ static inline int devfreq_update_stats(struct devfreq *df) { return -EINVAL; } + +static inline void devfreq_suspend(void) {} +static inline void devfreq_resume(void) {} #endif /* CONFIG_PM_DEVFREQ */ #endif /* __LINUX_DEVFREQ_H__ */
This suspend/resume operations works analogous to the cpufreq_{suspend,resume}() calls in the CPUFreq subsystem. Signed-off-by: Tobias Jakobi <tjakobi@math.uni-bielefeld.de> --- drivers/devfreq/devfreq.c | 75 +++++++++++++++++++++++++++++++++++++++++++++++ include/linux/devfreq.h | 10 +++++++ 2 files changed, 85 insertions(+)