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>
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>
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>
