| Message ID | feab364d702ba62102f212b7d415d9f768159163.1568764439.git.leonard.crestez@nxp.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | PM / devfreq: Add dev_pm_qos support | expand |
On Wed, Sep 18, 2019 at 03:18:25AM +0300, Leonard Crestez wrote: > Register notifiers with the pm_qos framework in order to respond to > requests for MIN_FREQUENCY and MAX_FREQUENCY. To make it clear that this change on it's own is a NOP maybe add something like "No constraints are added for now though.", as in 67d874c3b2c6 ("cpufreq: Register notifiers with the PM QoS framework") > Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com> > --- > drivers/devfreq/devfreq.c | 71 +++++++++++++++++++++++++++++++++++++++ > include/linux/devfreq.h | 5 +++ > 2 files changed, 76 insertions(+) > > diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c > index 51a4179e2c69..d8d57318b12c 100644 > --- a/drivers/devfreq/devfreq.c > +++ b/drivers/devfreq/devfreq.c > @@ -22,17 +22,20 @@ > #include <linux/platform_device.h> > #include <linux/list.h> > #include <linux/printk.h> > #include <linux/hrtimer.h> > #include <linux/of.h> > +#include <linux/pm_qos.h> > #include "governor.h" > > #define HZ_PER_KHZ 1000 > > #define CREATE_TRACE_POINTS > #include <trace/events/devfreq.h> > > +#define HZ_PER_KHZ 1000 > + > static struct class *devfreq_class; > > /* > * devfreq core provides delayed work based load monitoring helper > * functions. Governors can use these or can implement their own > @@ -123,10 +126,16 @@ static void devfreq_get_freq_range(struct devfreq *devfreq, > } else { > *min_freq = freq_table[devfreq->profile->max_state - 1]; > *max_freq = freq_table[0]; > } > > + /* constraints from dev_pm_qos: */ nit: QoS constraints? > + *min_freq = max(*min_freq, HZ_PER_KHZ * (unsigned long)dev_pm_qos_read_value( > + devfreq->dev.parent, DEV_PM_QOS_MIN_FREQUENCY)); > + *max_freq = min(*max_freq, HZ_PER_KHZ * (unsigned long)dev_pm_qos_read_value( > + devfreq->dev.parent, DEV_PM_QOS_MAX_FREQUENCY)); > + > /* constraints from sysfs: */ > *min_freq = max(*min_freq, devfreq->min_freq); > *max_freq = min(*max_freq, devfreq->max_freq); > > /* constraints from opp interface: */ > @@ -605,10 +614,49 @@ static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type, > mutex_unlock(&devfreq->lock); > > return ret; > } > > +/** > + * devfreq_qos_notifier_call() - Common handler for qos freq changes. nit: QoS s/freq/constraint/ ? > + * @devfreq: the devfreq instance. > + */ > +static int devfreq_qos_notifier_call(struct devfreq *devfreq) > +{ > + int ret; > + > + mutex_lock(&devfreq->lock); > + ret = update_devfreq(devfreq); > + mutex_unlock(&devfreq->lock); > + > + return ret; > +} > + > +/** > + * devfreq_qos_min_notifier_call() - Callback for qos min_freq changes. nit: QoS > + * @nb: Should to be devfreq->nb_min s/to// > + */ > +static int devfreq_qos_min_notifier_call(struct notifier_block *nb, > + unsigned long val, void *ptr) > +{ > + struct devfreq *devfreq = container_of(nb, struct devfreq, nb_min); > + > + return devfreq_qos_notifier_call(devfreq); > +} > + > +/** > + * devfreq_qos_max_notifier_call() - Callback for qos min_freq changes. nit: QoS s/min/max/ > + * @nb: Should to be devfreq->nb_max s/to// > + */ > +static int devfreq_qos_max_notifier_call(struct notifier_block *nb, > + unsigned long val, void *ptr) > +{ > + struct devfreq *devfreq = container_of(nb, struct devfreq, nb_max); > + > + return devfreq_qos_notifier_call(devfreq); > +} > + > /** > * devfreq_dev_release() - Callback for struct device to release the device. > * @dev: the devfreq device > * > * Remove devfreq from the list and release its resources. > @@ -619,10 +667,15 @@ static void devfreq_dev_release(struct device *dev) > > mutex_lock(&devfreq_list_lock); > list_del(&devfreq->node); > mutex_unlock(&devfreq_list_lock); > > + dev_pm_qos_remove_notifier(devfreq->dev.parent, &devfreq->nb_max, > + DEV_PM_QOS_MAX_FREQUENCY); > + dev_pm_qos_remove_notifier(devfreq->dev.parent, &devfreq->nb_min, > + DEV_PM_QOS_MIN_FREQUENCY); > + mega-nit: removing 'max' then 'min' does things in reverse order as during initialization, which is common practice. But since the order here doesn't really matter I'd stick to the common min/max order, might readers save a few milli-seconds wondering why 'max' comes first. > if (devfreq->profile->exit) > devfreq->profile->exit(devfreq->dev.parent); > > mutex_destroy(&devfreq->lock); > kfree(devfreq->time_in_state); > @@ -732,10 +785,27 @@ struct devfreq *devfreq_add_device(struct device *dev, > if (err) { > put_device(&devfreq->dev); > goto err_out; > } > > + /* > + * Register notifiers for updates to min_freq/max_freq after device is nit: min/max_freq? > + * initialized (and we can handle notifications) but before the governor > + * is started (which should do an initial enforcement of constraints) > + */ > + devfreq->nb_min.notifier_call = devfreq_qos_min_notifier_call; > + err = dev_pm_qos_add_notifier(devfreq->dev.parent, &devfreq->nb_min, > + DEV_PM_QOS_MIN_FREQUENCY); > + if (err) > + goto err_devfreq; IIUC you rely on the notifiers being removed by devfreq_dev_release(). Does dev_pm_qos_remove_notifier() behave gracefully if the notifier is not initialized/added or do we need to use BLOCKING_NOTIFIER_INIT() or similar?
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c index 51a4179e2c69..d8d57318b12c 100644 --- a/drivers/devfreq/devfreq.c +++ b/drivers/devfreq/devfreq.c @@ -22,17 +22,20 @@ #include <linux/platform_device.h> #include <linux/list.h> #include <linux/printk.h> #include <linux/hrtimer.h> #include <linux/of.h> +#include <linux/pm_qos.h> #include "governor.h" #define HZ_PER_KHZ 1000 #define CREATE_TRACE_POINTS #include <trace/events/devfreq.h> +#define HZ_PER_KHZ 1000 + static struct class *devfreq_class; /* * devfreq core provides delayed work based load monitoring helper * functions. Governors can use these or can implement their own @@ -123,10 +126,16 @@ static void devfreq_get_freq_range(struct devfreq *devfreq, } else { *min_freq = freq_table[devfreq->profile->max_state - 1]; *max_freq = freq_table[0]; } + /* constraints from dev_pm_qos: */ + *min_freq = max(*min_freq, HZ_PER_KHZ * (unsigned long)dev_pm_qos_read_value( + devfreq->dev.parent, DEV_PM_QOS_MIN_FREQUENCY)); + *max_freq = min(*max_freq, HZ_PER_KHZ * (unsigned long)dev_pm_qos_read_value( + devfreq->dev.parent, DEV_PM_QOS_MAX_FREQUENCY)); + /* constraints from sysfs: */ *min_freq = max(*min_freq, devfreq->min_freq); *max_freq = min(*max_freq, devfreq->max_freq); /* constraints from opp interface: */ @@ -605,10 +614,49 @@ static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type, mutex_unlock(&devfreq->lock); return ret; } +/** + * devfreq_qos_notifier_call() - Common handler for qos freq changes. + * @devfreq: the devfreq instance. + */ +static int devfreq_qos_notifier_call(struct devfreq *devfreq) +{ + int ret; + + mutex_lock(&devfreq->lock); + ret = update_devfreq(devfreq); + mutex_unlock(&devfreq->lock); + + return ret; +} + +/** + * devfreq_qos_min_notifier_call() - Callback for qos min_freq changes. + * @nb: Should to be devfreq->nb_min + */ +static int devfreq_qos_min_notifier_call(struct notifier_block *nb, + unsigned long val, void *ptr) +{ + struct devfreq *devfreq = container_of(nb, struct devfreq, nb_min); + + return devfreq_qos_notifier_call(devfreq); +} + +/** + * devfreq_qos_max_notifier_call() - Callback for qos min_freq changes. + * @nb: Should to be devfreq->nb_max + */ +static int devfreq_qos_max_notifier_call(struct notifier_block *nb, + unsigned long val, void *ptr) +{ + struct devfreq *devfreq = container_of(nb, struct devfreq, nb_max); + + return devfreq_qos_notifier_call(devfreq); +} + /** * devfreq_dev_release() - Callback for struct device to release the device. * @dev: the devfreq device * * Remove devfreq from the list and release its resources. @@ -619,10 +667,15 @@ static void devfreq_dev_release(struct device *dev) mutex_lock(&devfreq_list_lock); list_del(&devfreq->node); mutex_unlock(&devfreq_list_lock); + dev_pm_qos_remove_notifier(devfreq->dev.parent, &devfreq->nb_max, + DEV_PM_QOS_MAX_FREQUENCY); + dev_pm_qos_remove_notifier(devfreq->dev.parent, &devfreq->nb_min, + DEV_PM_QOS_MIN_FREQUENCY); + if (devfreq->profile->exit) devfreq->profile->exit(devfreq->dev.parent); mutex_destroy(&devfreq->lock); kfree(devfreq->time_in_state); @@ -732,10 +785,27 @@ struct devfreq *devfreq_add_device(struct device *dev, if (err) { put_device(&devfreq->dev); goto err_out; } + /* + * Register notifiers for updates to min_freq/max_freq after device is + * initialized (and we can handle notifications) but before the governor + * is started (which should do an initial enforcement of constraints) + */ + devfreq->nb_min.notifier_call = devfreq_qos_min_notifier_call; + err = dev_pm_qos_add_notifier(devfreq->dev.parent, &devfreq->nb_min, + DEV_PM_QOS_MIN_FREQUENCY); + if (err) + goto err_devfreq; + + devfreq->nb_max.notifier_call = devfreq_qos_max_notifier_call; + err = dev_pm_qos_add_notifier(devfreq->dev.parent, &devfreq->nb_max, + DEV_PM_QOS_MAX_FREQUENCY); + if (err) + goto err_devfreq; + mutex_lock(&devfreq_list_lock); governor = try_then_request_governor(devfreq->governor_name); if (IS_ERR(governor)) { dev_err(dev, "%s: Unable to find governor for the device\n", @@ -759,10 +829,11 @@ struct devfreq *devfreq_add_device(struct device *dev, return devfreq; err_init: mutex_unlock(&devfreq_list_lock); +err_devfreq: devfreq_remove_device(devfreq); return ERR_PTR(err); err_dev: kfree(devfreq->time_in_state); kfree(devfreq->trans_table); diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h index c3cbc15fdf08..dac0dffeabb4 100644 --- a/include/linux/devfreq.h +++ b/include/linux/devfreq.h @@ -134,10 +134,12 @@ struct devfreq_dev_profile { * @total_trans: Number of devfreq transitions * @trans_table: Statistics of devfreq transitions * @time_in_state: Statistics of devfreq states * @last_stat_updated: The last time stat updated * @transition_notifier_list: list head of DEVFREQ_TRANSITION_NOTIFIER notifier + * @nb_min: Notifier block for DEV_PM_QOS_MIN_FREQUENCY + * @nb_max: Notifier block for DEV_PM_QOS_MAX_FREQUENCY * * This structure stores the devfreq information for a give device. * * Note that when a governor accesses entries in struct devfreq in its * functions except for the context of callbacks defined in struct @@ -176,10 +178,13 @@ struct devfreq { unsigned int *trans_table; unsigned long *time_in_state; unsigned long last_stat_updated; struct srcu_notifier_head transition_notifier_list; + + struct notifier_block nb_min; + struct notifier_block nb_max; }; struct devfreq_freqs { unsigned long old; unsigned long new;
Register notifiers with the pm_qos framework in order to respond to requests for MIN_FREQUENCY and MAX_FREQUENCY. Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com> --- drivers/devfreq/devfreq.c | 71 +++++++++++++++++++++++++++++++++++++++ include/linux/devfreq.h | 5 +++ 2 files changed, 76 insertions(+)