Add Kconfig, Make.defs, and CMakeLists.txt entries for the ondemand governor so it can be enabled via CONFIG_DEVFREQ_GOV_ONDEMAND.
Signed-off-by: guanyi3 <guanyi3@xiaomi.com>
When CONFIG_LIBC_BACKTRACE_DEPTH is not set or <= 0, backtrace_get()
is a macro that always sets depth to 0, making the for-loop body
unreachable (Coverity CID 8405332 DEADCODE).
Wrap backtrace_get() call, the loop, and related variable declarations
with #if CONFIG_LIBC_BACKTRACE_DEPTH > 0 to eliminate the dead code
and avoid unused variable warnings.
Signed-off-by: guanyi3 <guanyi3@xiaomi.com>
QOS_REQ_MIN should return the highest value among all min requests
(most restrictive lower bound), but plist_first returns the lowest.
QOS_REQ_MAX should return the lowest value among all max requests
(most restrictive upper bound), but plist_last returns the highest.
This caused qos constraints to be ineffective. For example, two
requests (32, 208000) and (104000, 104000) would merge to (32, 208000)
instead of the correct (104000, 104000).
Fix by using plist_last for QOS_REQ_MIN and plist_first for QOS_REQ_MAX.
Signed-off-by: guanyi3 <guanyi3@xiaomi.com>
The cached devfreq->cur may become stale when the hardware frequency is
changed externally (e.g. by another core or governor). This causes
driver_target to incorrectly skip frequency transitions when the target
matches the cached value but differs from the actual hardware frequency.
Use driver->get_frequency() to read the real hardware frequency for the
unchanged check, and sync devfreq->cur on match to keep the cache correct.
Signed-off-by: guanyi3 <guanyi3@xiaomi.com>
When devfreq_gov_ondemand_stop() is called from idle task context,
work_cancel() is used instead of work_cancel_sync(), which does not
wait for the currently running worker to complete. If
devfreq_gov_ondemand_exit() then frees governor_data, the worker
may still be accessing it, causing a use-after-free crash.
Fix this by:
- Nullifying dev->governor_data under dev->lock in exit before freeing.
- Moving the governor_data read inside dev->lock in the worker and
adding a NULL check to bail out early if data has been freed.
Signed-off-by: guanyi3 <guanyi3@xiaomi.com>
When multiple QoS requests have no overlapping frequency range (min > max), the previous behavior always clamped to the lower frequency. Add a conflict_policy field to devfreq_driver_s so callers can choose between DEVFREQ_CONFLICT_PREFER_HIGH (default, choose higher freq) and DEVFREQ_CONFLICT_PREFER_LOW (choose lower freq) at registration.
Signed-off-by: guanyi3 <guanyi3@xiaomi.com>
Add the ability to set frequency constraints via procfs write.
Supported formats:
echo <min>,<max> > /proc/devfreq/<name> - set frequency range
echo 0,0 > /proc/devfreq/<name> - remove constraint
The QoS request is bound to the devfreq device lifetime so that
shell commands like echo (which open, write, close immediately)
work correctly. Leading whitespace in the write buffer is skipped
to handle extra writes from nsh echo (e.g. trailing newline).
Also add write permissions in devfreq_stat() and a procfs_qos
field in devfreq_s guarded by CONFIG_DEVFREQ_PROCFS.
Signed-off-by: guanyi3 <guanyi3@xiaomi.com>
(cherry picked from commit 70ae195c84f35a4d0b85fcc14187989b60fc0280)
we may call devfreq_find_by_name() in pm_callback, and shouldn't call nxmutex_lock() in idle_loop, so replace mutex to spinlock.
Signed-off-by: guanyi3 <guanyi3@xiaomi.com>
Add devfreq ondemand governor that scales device frequency based on CPU load. When CPU load exceeds the configured threshold, frequency is set to maximum; otherwise it is scaled proportionally.
Signed-off-by: guanyi3 <guanyi3@xiaomi.com>
It's better not to use global governor, as modifying one device will cause all devices' governor to be modified.
Signed-off-by: guanyi3 <guanyi3@xiaomi.com>
This commit introduces a devfreq framework to manage device frequency
scaling. The framework includes the following features:
1.devfreq governor
- provide governor ops, including init, start, stop, exit
- default governor, performance & powersave
- customized governor, device can provide governor when register
2.runtime register and unregister
- device can runtime register & unregister, search by name
3.suspend and resume
- suspend and resume frequency scaling
4.notify
- register & unregister notifier callback, notify frequency changes
5.qos support
- simplified QoS, manage multiple freq range request
- including init, add/remove/update request, get value
Signed-off-by: guanyi <guanyi@xiaomi.com>
