On SoCs, where the governor and the mechanism to control the frequency for devices like caches is hosted on the System Control Processor (SCP), there exists a need track the frequency changes in a reliable way and provide ways to tweaking parameters on the remote governor.
To address this introduce the new remote devfreq governor that provides for a way to track the frequency changes on remote devices. It uses the newly introduced target_freq attribute flag and track_remote flag to achieve this. Signed-off-by: Sibi Sankar <[email protected]> --- drivers/devfreq/Kconfig | 8 ++++ drivers/devfreq/Makefile | 1 + drivers/devfreq/governor_remote.c | 80 +++++++++++++++++++++++++++++++ include/linux/devfreq.h | 1 + 4 files changed, 90 insertions(+) create mode 100644 drivers/devfreq/governor_remote.c diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig index c999c4a1e567..2caa87554914 100644 --- a/drivers/devfreq/Kconfig +++ b/drivers/devfreq/Kconfig @@ -56,6 +56,14 @@ config DEVFREQ_GOV_POWERSAVE the DEVFREQ framework returns the lowest frequency available at any time. +config DEVFREQ_GOV_REMOTE + tristate "Remote" + help + A simple governor to track the frequency of devices whose + dvfs control lies outside the kernel. This governor acts + as an observer and provides for ways to track frequency and + set/get information related to the remote dvfs device. + config DEVFREQ_GOV_USERSPACE tristate "Userspace" help diff --git a/drivers/devfreq/Makefile b/drivers/devfreq/Makefile index 404179d79a9d..cde57c8cda76 100644 --- a/drivers/devfreq/Makefile +++ b/drivers/devfreq/Makefile @@ -4,6 +4,7 @@ obj-$(CONFIG_PM_DEVFREQ_EVENT) += devfreq-event.o obj-$(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND) += governor_simpleondemand.o obj-$(CONFIG_DEVFREQ_GOV_PERFORMANCE) += governor_performance.o obj-$(CONFIG_DEVFREQ_GOV_POWERSAVE) += governor_powersave.o +obj-$(CONFIG_DEVFREQ_GOV_REMOTE) += governor_remote.o obj-$(CONFIG_DEVFREQ_GOV_USERSPACE) += governor_userspace.o obj-$(CONFIG_DEVFREQ_GOV_PASSIVE) += governor_passive.o diff --git a/drivers/devfreq/governor_remote.c b/drivers/devfreq/governor_remote.c new file mode 100644 index 000000000000..6bff3cdaf1e5 --- /dev/null +++ b/drivers/devfreq/governor_remote.c @@ -0,0 +1,80 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) Qualcomm Innovation Center, Inc. All rights reserved. + */ + +#include <linux/errno.h> +#include <linux/module.h> +#include <linux/devfreq.h> +#include <linux/devfreq-governor.h> + +static int devfreq_remote_track_func(struct devfreq *devfreq, unsigned long *freq) +{ + unsigned long cur_freq = 0; + + if (devfreq->profile->get_cur_freq) + devfreq->profile->get_cur_freq(devfreq->dev.parent, &cur_freq); + + *freq = cur_freq; + + return 0; +} + +static int devfreq_remote_track_handler(struct devfreq *devfreq, unsigned int event, void *data) +{ + switch (event) { + case DEVFREQ_GOV_START: + devfreq_monitor_start(devfreq); + break; + + case DEVFREQ_GOV_STOP: + devfreq_monitor_stop(devfreq); + break; + + case DEVFREQ_GOV_UPDATE_INTERVAL: + devfreq_update_interval(devfreq, (unsigned int *)data); + break; + + case DEVFREQ_GOV_SUSPEND: + devfreq_monitor_suspend(devfreq); + break; + + case DEVFREQ_GOV_RESUME: + devfreq_monitor_resume(devfreq); + break; + + default: + break; + } + + return 0; +} + +static struct devfreq_governor devfreq_remote_track = { + .name = DEVFREQ_GOV_REMOTE, + .attrs = DEVFREQ_GOV_ATTR_POLLING_INTERVAL + | DEVFREQ_GOV_ATTR_TIMER, + .flags = DEVFREQ_GOV_FLAG_IMMUTABLE + | DEVFREQ_GOV_FLAG_TRACK_REMOTE, + .get_target_freq = devfreq_remote_track_func, + .event_handler = devfreq_remote_track_handler, +}; + +static int __init devfreq_remote_track_init(void) +{ + return devfreq_add_governor(&devfreq_remote_track); +} +subsys_initcall(devfreq_remote_track_init); + +static void __exit devfreq_remote_track_exit(void) +{ + int ret; + + ret = devfreq_remove_governor(&devfreq_remote_track); + if (ret) + pr_err("%s: failed remove governor %d\n", __func__, ret); +} +module_exit(devfreq_remote_track_exit); + +MODULE_DESCRIPTION("DEVFREQ Remote Tracking governor"); +MODULE_LICENSE("GPL"); diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h index dc1075dc3446..4d50cf230950 100644 --- a/include/linux/devfreq.h +++ b/include/linux/devfreq.h @@ -21,6 +21,7 @@ #define DEVFREQ_GOV_POWERSAVE "powersave" #define DEVFREQ_GOV_USERSPACE "userspace" #define DEVFREQ_GOV_PASSIVE "passive" +#define DEVFREQ_GOV_REMOTE "remote" /* DEVFREQ notifier interface */ #define DEVFREQ_TRANSITION_NOTIFIER (0) -- 2.34.1
