From 05d7ae15cfb18f9ce55eef85bb6bcd62d31acc57 Mon Sep 17 00:00:00 2001 From: Leonard Crestez Date: Thu, 5 Dec 2019 12:05:06 +0200 Subject: [PATCH] PM / devfreq: Add PM QoS support Register notifiers with the PM QoS framework in order to respond to requests for DEV_PM_QOS_MIN_FREQUENCY and DEV_PM_QOS_MAX_FREQUENCY. No notifiers are added by this patch but PM QoS constraints can be imposed externally (for example from other devices). Signed-off-by: Leonard Crestez Acked-by: Chanwoo Choi Reviewed-by: Matthias Kaehlcke Tested-by: Matthias Kaehlcke Signed-off-by: Chanwoo Choi --- drivers/devfreq/devfreq.c | 77 +++++++++++++++++++++++++++++++++++++++ include/linux/devfreq.h | 5 +++ 2 files changed, 82 insertions(+) diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c index 59f9fa8b54d1..f6e272085448 100644 --- a/drivers/devfreq/devfreq.c +++ b/drivers/devfreq/devfreq.c @@ -24,11 +24,14 @@ #include #include #include +#include #include "governor.h" #define CREATE_TRACE_POINTS #include +#define HZ_PER_KHZ 1000 + static struct class *devfreq_class; /* @@ -111,6 +114,7 @@ static void get_freq_range(struct devfreq *devfreq, unsigned long *max_freq) { unsigned long *freq_table = devfreq->profile->freq_table; + s32 qos_min_freq, qos_max_freq; lockdep_assert_held(&devfreq->lock); @@ -127,6 +131,16 @@ static void get_freq_range(struct devfreq *devfreq, *max_freq = freq_table[0]; } + /* Apply constraints from PM QoS */ + qos_min_freq = dev_pm_qos_read_value(devfreq->dev.parent, + DEV_PM_QOS_MIN_FREQUENCY); + qos_max_freq = dev_pm_qos_read_value(devfreq->dev.parent, + DEV_PM_QOS_MAX_FREQUENCY); + *min_freq = max(*min_freq, (unsigned long)HZ_PER_KHZ * qos_min_freq); + if (qos_max_freq != PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE) + *max_freq = min(*max_freq, + (unsigned long)HZ_PER_KHZ * qos_max_freq); + /* Apply constraints from sysfs */ *min_freq = max(*min_freq, devfreq->min_freq); *max_freq = min(*max_freq, devfreq->max_freq); @@ -626,6 +640,45 @@ out: return NOTIFY_OK; } +/** + * qos_notifier_call() - Common handler for QoS constraints. + * @devfreq: the devfreq instance. + */ +static int qos_notifier_call(struct devfreq *devfreq) +{ + int err; + + mutex_lock(&devfreq->lock); + err = update_devfreq(devfreq); + mutex_unlock(&devfreq->lock); + if (err) + dev_err(devfreq->dev.parent, + "failed to update frequency from PM QoS (%d)\n", + err); + + return NOTIFY_OK; +} + +/** + * qos_min_notifier_call() - Callback for QoS min_freq changes. + * @nb: Should be devfreq->nb_min + */ +static int qos_min_notifier_call(struct notifier_block *nb, + unsigned long val, void *ptr) +{ + return qos_notifier_call(container_of(nb, struct devfreq, nb_min)); +} + +/** + * qos_max_notifier_call() - Callback for QoS max_freq changes. + * @nb: Should be devfreq->nb_max + */ +static int qos_max_notifier_call(struct notifier_block *nb, + unsigned long val, void *ptr) +{ + return qos_notifier_call(container_of(nb, struct devfreq, nb_max)); +} + /** * devfreq_dev_release() - Callback for struct device to release the device. * @dev: the devfreq device @@ -635,11 +688,23 @@ out: static void devfreq_dev_release(struct device *dev) { struct devfreq *devfreq = to_devfreq(dev); + int err; mutex_lock(&devfreq_list_lock); list_del(&devfreq->node); mutex_unlock(&devfreq_list_lock); + err = dev_pm_qos_remove_notifier(devfreq->dev.parent, &devfreq->nb_max, + DEV_PM_QOS_MAX_FREQUENCY); + if (err && err != -ENOENT) + dev_warn(dev->parent, + "Failed to remove max_freq notifier: %d\n", err); + err = dev_pm_qos_remove_notifier(devfreq->dev.parent, &devfreq->nb_min, + DEV_PM_QOS_MIN_FREQUENCY); + if (err && err != -ENOENT) + dev_warn(dev->parent, + "Failed to remove min_freq notifier: %d\n", err); + if (devfreq->profile->exit) devfreq->profile->exit(devfreq->dev.parent); @@ -762,6 +827,18 @@ struct devfreq *devfreq_add_device(struct device *dev, mutex_unlock(&devfreq->lock); + devfreq->nb_min.notifier_call = 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 = 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); diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h index 2bae9ed3c783..8b92ccbd1962 100644 --- a/include/linux/devfreq.h +++ b/include/linux/devfreq.h @@ -136,6 +136,8 @@ struct devfreq_dev_profile { * @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. * @@ -178,6 +180,9 @@ struct devfreq { 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 {