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path: root/drivers/devfreq/governor_passive.c
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2022-05-19PM / devfreq: passive: Return non-error when not-supported event is requiredChanwoo Choi1-1/+1
Each devfreq governor specifies the supported governor event such as GOV_START and GOV_STOP. When not-supported event is required, just return non-error. But, commit ce9a0d88d97a ("PM / devfreq: Add cpu based scaling support to passive governor") returned the error value. So that return non-error value when not-supported event is required. Fixes: ce9a0d88d97a ("PM / devfreq: Add cpu based scaling support to passive governor") Reported-by: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2022-05-17PM / devfreq: passive: Keep cpufreq_policy for possible cpusChanwoo Choi1-16/+59
The passive governor requires the cpu data to get the next target frequency of devfreq device if depending on cpu. In order to reduce the unnecessary memory data, keep cpufreq_policy data for possible cpus instead of NR_CPU. Tested-by: Chen-Yu Tsai <wenst@chromium.org> Tested-by: Johnson Wang <johnson.wang@mediatek.com> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
2022-05-17PM / devfreq: passive: Reduce duplicate code when passive_devfreq caseChanwoo Choi1-58/+8
In order to keep the consistent coding style between passive_devfreq and passive_cpufreq, use common code for handling required opp property. Also remove the unneed conditional statement and unify the comment of both passive_devfreq and passive_cpufreq when getting the target frequency. Tested-by: Chen-Yu Tsai <wenst@chromium.org> Tested-by: Johnson Wang <johnson.wang@mediatek.com> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
2022-05-17PM / devfreq: Add cpu based scaling support to passive governorSaravana Kannan1-12/+286
Many CPU architectures have caches that can scale independent of the CPUs. Frequency scaling of the caches is necessary to make sure that the cache is not a performance bottleneck that leads to poor performance and power. The same idea applies for RAM/DDR. To achieve this, this patch adds support for cpu based scaling to the passive governor. This is accomplished by taking the current frequency of each CPU frequency domain and then adjust the frequency of the cache (or any devfreq device) based on the frequency of the CPUs. It listens to CPU frequency transition notifiers to keep itself up to date on the current CPU frequency. To decide the frequency of the device, the governor does one of the following: * Derives the optimal devfreq device opp from required-opps property of the parent cpu opp_table. * Scales the device frequency in proportion to the CPU frequency. So, if the CPUs are running at their max frequency, the device runs at its max frequency. If the CPUs are running at their min frequency, the device runs at its min frequency. It is interpolated for frequencies in between. Tested-by: Chen-Yu Tsai <wenst@chromium.org> Tested-by: Johnson Wang <johnson.wang@mediatek.com> Signed-off-by: Saravana Kannan <skannan@codeaurora.org> [Sibi: Integrated cpu-freqmap governor into passive_governor] Signed-off-by: Sibi Sankar <sibis@codeaurora.org> [Chanwoo: Fix conflict with latest code and cleanup code] Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
2021-06-24PM / devfreq: passive: Fix get_target_freq when not using required-oppChanwoo Choi1-1/+2
The 86ad9a24f21e ("PM / devfreq: Add required OPPs support to passive governor") supported the required-opp property for using devfreq passive governor. But, 86ad9a24f21e has caused the problem on use-case when required-opp is not used such as exynos-bus.c devfreq driver. So that fix the get_target_freq of passive governor for supporting the case of when required-opp is not used. Fixes: 86ad9a24f21e ("PM / devfreq: Add required OPPs support to passive governor") Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
2021-02-04PM / devfreq: Add required OPPs support to passive governorSaravana Kannan1-19/+25
Look at the required OPPs of the "parent" device to determine the OPP that is required from the slave device managed by the passive governor. This allows having mappings between a parent device and a slave device even when they don't have the same number of OPPs. While at it do a minor spell-fix and remove out label. Signed-off-by: Saravana Kannan <saravanak@google.com> Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com> Acked-by: Chanwoo Choi <cw00.choi@samsung.com> Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org> [ Viresh: Rearranged code and clean error paths ] Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
2020-10-26PM / devfreq: Add governor feature flagChanwoo Choi1-1/+1
The devfreq governor is able to have the specific flag as follows in order to implement the specific feature. For example, devfreq allows user to change the governors on runtime via sysfs interface. But, if devfreq device uses 'passive' governor, don't allow user to change the governor. For this case, define the DEVFREQ_GOV_FLAG_IMMUTABLE and set it to flag of passive governor. [Definition for governor flag] - DEVFREQ_GOV_FLAG_IMMUTABLE : If immutable flag is set, governor is never changeable to other governors. - DEVFREQ_GOV_FLAG_IRQ_DRIVEN : Devfreq core won't schedule polling work for this governor if value is set. [Table of governor flag for devfreq governors] ------------------------------------------------------------------------------ | simple | perfor | power | user | passive | tegra30 | ondemand | mance | save | space| | ------------------------------------------------------------------------------ immutable | X | X | X | X | O | O interrupt_driven | X(polling)| X | X | X | X | O (irq) ------------------------------------------------------------------------------ Reviewed-by: Dmitry Osipenko <digetx@gmail.com> Tested-by: Dmitry Osipenko <digetx@gmail.com> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
2020-10-26PM / devfreq: Unify frequency change to devfreq_update_target funcChanwoo Choi1-32/+10
The update_devfreq() and update_passive_devfreq() have the duplicate code when changing the target frequency on final stage. So, unify frequency change code to devfreq_update_target() to remove the duplicate code and to centralize the frequency change code. Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
2019-08-26PM / devfreq: passive: fix compiler warningMyungJoo Ham1-1/+0
The recent commit of PM / devfreq: passive: Use non-devm notifiers had incurred compiler warning, "unused variable 'dev'". Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
2019-08-25PM / devfreq: passive: Use non-devm notifiersLeonard Crestez1-3/+3
The devfreq passive governor registers and unregisters devfreq transition notifiers on DEVFREQ_GOV_START/GOV_STOP using devm wrappers. If devfreq itself is registered with devm then a warning is triggered on rmmod from devm_devfreq_unregister_notifier. Call stack looks like this: devm_devfreq_unregister_notifier+0x30/0x40 devfreq_passive_event_handler+0x4c/0x88 devfreq_remove_device.part.8+0x6c/0x9c devm_devfreq_dev_release+0x18/0x20 release_nodes+0x1b0/0x220 devres_release_all+0x78/0x84 device_release_driver_internal+0x100/0x1c0 driver_detach+0x4c/0x90 bus_remove_driver+0x7c/0xd0 driver_unregister+0x2c/0x58 platform_driver_unregister+0x10/0x18 imx_devfreq_platdrv_exit+0x14/0xd40 [imx_devfreq] This happens because devres_release_all will first remove all the nodes into a separate todo list so the nested devres_release from devm_devfreq_unregister_notifier won't find anything. Fix the warning by calling the non-devm APIS for frequency notification. Using devm wrappers is not actually useful for a governor anyway: it relies on the devfreq core to correctly match the GOV_START/GOV_STOP notifications. Fixes: 996133119f57 ("PM / devfreq: Add new passive governor") Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com> Acked-by: Chanwoo Choi <cw00.choi@samsung.com> Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
2019-06-19treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500Thomas Gleixner1-4/+1
Based on 2 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation # extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 4122 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Enrico Weigelt <info@metux.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-10-26PM / devfreq: Define the constant governor nameChanwoo Choi1-1/+1
Prior to that, the devfreq device uses the governor name when adding the itself. In order to prevent the mistake used the wrong governor name, this patch defines the governor name as a constant and then uses them instead of using the string directly. Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com> Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com> Cc: Kukjin Kim <kgene@kernel.org> Cc: Krzysztof Kozlowski <krzk@kernel.org> Cc: linux-samsung-soc@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org
2017-02-20Merge branch 'pm-devfreq'Rafael J. Wysocki1-0/+6
* pm-devfreq: PM / devfreq: Modify the device name as devfreq(X) for sysfs PM / devfreq: Simplify the sysfs name of devfreq-event device PM / devfreq: Remove unnecessary separate _remove_devfreq() PM / devfreq: Fix wrong trans_stat of passive devfreq device PM / devfreq: Fix available_governor sysfs PM / devfreq: exynos-ppmu: Show the registred device for ppmu device PM / devfreq: Fix the wrong description for userspace governor PM / devfreq: Fix the checkpatch warnings PM / devfreq: exynos-bus: Print the real clock rate of bus PM / devfreq: exynos-ppmu: Use the regmap interface to handle the registers PM / devfreq: exynos-bus: Add the detailed correlation for Exynos5433 PM / devfreq: Don't delete sysfs group twice
2017-01-31PM / devfreq: Fix wrong trans_stat of passive devfreq deviceChanwoo Choi1-0/+5
Until now, the trans_stat information of passive devfreq is not updated. This patch updates the trans_stat information after setting the target frequency of passive devfreq device. Fixes: 996133119f57 ("PM / devfreq: Add new passive governor") Cc: stable@vger.kernel.org Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com> Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
2017-01-31PM / devfreq: Fix available_governor sysfsChanwoo Choi1-0/+1
The devfreq using passive governor is not able to change the governor. So, the user can not change the governor through 'available_governor' sysfs entry. Also, the devfreq which don't use the passive governor is not able to change to 'passive' governor on the fly. Fixes: 996133119f57 ("PM / devfreq: Add new passive governor") Cc: stable@vger.kernel.org Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com> Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
2017-01-30PM / OPP: Update OPP users to put referenceViresh Kumar1-2/+2
This patch updates dev_pm_opp_find_freq_*() routines to get a reference to the OPPs returned by them. Also updates the users of dev_pm_opp_find_freq_*() routines to call dev_pm_opp_put() after they are done using the OPPs. As it is guaranteed the that OPPs wouldn't get freed while being used, the RCU read side locking present with the users isn't required anymore. Drop it as well. This patch also updates all users of devfreq_recommended_opp() which was returning an OPP received from the OPP core. Note that some of the OPP core routines have gained rcu_read_{lock|unlock}() calls, as those still use RCU specific APIs within them. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com> [Devfreq] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-05-03PM / devfreq: style/typo fixesMyungJoo Ham1-2/+0
- Typo in comments fixed - Unnecessary return statement removed Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
2016-05-03PM / devfreq: Add new passive governorChanwoo Choi1-0/+207
This patch adds the new passive governor for DEVFREQ framework. The following governors are already present and used for DVFS (Dynamic Voltage and Frequency Scaling) drivers. The following governors are independently used for one device driver which don't give the influence to other device drviers and also don't receive the effect from other device drivers. - ondemand / performance / powersave / userspace The passive governor depends on operation of parent driver with specific governos extremely and is not able to decide the new frequency by oneself. According to the decided new frequency of parent driver with governor, the passive governor uses it to decide the appropriate frequency for own device driver. The passive governor must need the following information from device tree: - the source clock and OPP tables - the instance of parent device For exameple, there are one more devfreq device drivers which need to change their source clock according to their utilization on runtime. But, they share the same power line (e.g., regulator). So, specific device driver is operated as parent with ondemand governor and then the rest device driver with passive governor is influenced by parent device. Suggested-by: Myungjoo Ham <myungjoo.ham@samsung.com> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com> [tjakobi: Reported RCU locking issue and cw00.choi fix it] Reported-by: Tobias Jakobi <tjakobi@math.uni-bielefeld.de> [linux.amoon: Reported possible recursive locking and cw00.choi fix it] Reported-by: Anand Moon <linux.amoon@gmail.com> Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com> Acked-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>