Commit Graph

18 Commits

Author SHA1 Message Date
Chanwoo Choi 42d2607d91 PM / devfreq: passive: Return non-error when not-supported event is required
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>
2022-05-19 19:32:19 +02:00
Chanwoo Choi 26984d9d58 PM / devfreq: passive: Keep cpufreq_policy for possible cpus
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>
2022-05-17 18:24:39 +09:00
Chanwoo Choi 05723e7123 PM / devfreq: passive: Reduce duplicate code when passive_devfreq case
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>
2022-05-17 18:24:39 +09:00
Saravana Kannan a03dacb031 PM / devfreq: Add cpu based scaling support to passive governor
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>
2022-05-17 18:24:39 +09:00
Chanwoo Choi 8c37d01e1a PM / devfreq: passive: Fix get_target_freq when not using required-opp
The 86ad9a24f2 ("PM / devfreq: Add required OPPs support to passive governor")
supported the required-opp property for using devfreq passive governor.
But, 86ad9a24f2 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: 86ad9a24f2 ("PM / devfreq: Add required OPPs support to passive governor")
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
2021-06-24 10:37:35 +09:00
Saravana Kannan 86ad9a24f2 PM / devfreq: Add required OPPs support to passive governor
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>
2021-02-04 16:48:16 +05:30
Chanwoo Choi 0dd25a0d12 PM / devfreq: Add governor feature flag
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>
2020-10-26 10:54:41 +09:00
Chanwoo Choi b4365423bb PM / devfreq: Unify frequency change to devfreq_update_target func
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>
2020-10-26 10:52:37 +09:00
MyungJoo Ham 0465814831 PM / devfreq: passive: fix compiler warning
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>
2019-08-26 21:37:37 +09:00
Leonard Crestez 0ef7c7cce4 PM / devfreq: passive: Use non-devm notifiers
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: 996133119f ("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>
2019-08-25 12:47:31 +09:00
Thomas Gleixner d2912cb15b treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500
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>
2019-06-19 17:09:55 +02:00
Chanwoo Choi aa7c352f98 PM / devfreq: Define the constant governor name
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
2017-10-26 17:08:40 +09:00
Rafael J. Wysocki 41ef3d1df0 Merge branch 'pm-devfreq'
* 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
2017-02-20 14:23:40 +01:00
Chanwoo Choi 30582c25a4 PM / devfreq: Fix wrong trans_stat of passive devfreq device
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: 996133119f ("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>
2017-01-31 15:47:32 +09:00
Chanwoo Choi bcf23c79c4 PM / devfreq: Fix available_governor sysfs
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: 996133119f ("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>
2017-01-31 15:46:49 +09:00
Viresh Kumar 8a31d9d942 PM / OPP: Update OPP users to put reference
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>
2017-01-30 09:22:21 +01:00
MyungJoo Ham 83cb0e4d83 PM / devfreq: style/typo fixes
- Typo in comments fixed
- Unnecessary return statement removed

Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
2016-05-03 11:22:10 +09:00
Chanwoo Choi 996133119f PM / devfreq: Add new passive governor
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>
2016-05-03 11:20:07 +09:00