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PM / devfreq: Add common sysfs interfaces Device specific sysfs interface /sys/devices/.../power/devfreq_* - governor R: name of governor - cur_freq R: current frequency - polling_interval R: polling interval in ms given with devfreq profile W: update polling interval. - central_polling R: 1 if polling is managed by devfreq framework Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Reviewed-by: Mike Turquette <mturquette@ti.com> Acked-by: Kevin Hilman <khilman@ti.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> -- Documentation/ABI/testing/sysfs-class-devfreq | 44 ++++++++++++++++ drivers/devfreq/devfreq.c | 69 ++++++++++++++++++++++++++ 2 files changed, 113 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-class-devfreq
2011-10-01 22:19:28 +00:00
What: /sys/class/devfreq/.../
Date: September 2011
Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
Description:
Provide a place in sysfs for the devfreq objects.
This allows accessing various devfreq specific variables.
The name of devfreq object denoted as ... is same as the
name of device using devfreq.
PM / devfreq: Add new name attribute for sysfs The commit 4585fbcb5331 ("PM / devfreq: Modify the device name as devfreq(X) for sysfs") changed the node name to devfreq(x). After this commit, it is not possible to get the device name through /sys/class/devfreq/devfreq(X)/*. Add new name attribute in order to get device name. Cc: stable@vger.kernel.org Fixes: 4585fbcb5331 ("PM / devfreq: Modify the device name as devfreq(X) for sysfs") Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
2019-11-05 09:18:03 +00:00
What: /sys/class/devfreq/.../name
Date: November 2019
Contact: Chanwoo Choi <cw00.choi@samsung.com>
Description:
The /sys/class/devfreq/.../name shows the name of device
of the corresponding devfreq object.
PM / devfreq: Add common sysfs interfaces Device specific sysfs interface /sys/devices/.../power/devfreq_* - governor R: name of governor - cur_freq R: current frequency - polling_interval R: polling interval in ms given with devfreq profile W: update polling interval. - central_polling R: 1 if polling is managed by devfreq framework Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Reviewed-by: Mike Turquette <mturquette@ti.com> Acked-by: Kevin Hilman <khilman@ti.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> -- Documentation/ABI/testing/sysfs-class-devfreq | 44 ++++++++++++++++ drivers/devfreq/devfreq.c | 69 ++++++++++++++++++++++++++ 2 files changed, 113 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-class-devfreq
2011-10-01 22:19:28 +00:00
What: /sys/class/devfreq/.../governor
Date: September 2011
Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
Description:
PM / devfreq: allow sysfs governor node to switch governor This allows us to select governor runtime from the default configuration without having to rebuild kernel or the devfreq driver using the sysfs node: /sys/class/devfreq/.../governor cat of the governor will return valid governor and an echo 'governor_name'>governor will switch governor Cc: Rajagopal Venkat <rajagopal.venkat@linaro.org> Cc: MyungJoo Ham <myungjoo.ham@samsung.com> Cc: Kyungmin Park <kyungmin.park@samsung.com> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Kevin Hilman <khilman@ti.com> Cc: linux-pm@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Nishanth Menon <nm@ti.com> Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com> Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
2012-10-29 20:01:47 +00:00
The /sys/class/devfreq/.../governor show or set the name of the
PM / devfreq: Add common sysfs interfaces Device specific sysfs interface /sys/devices/.../power/devfreq_* - governor R: name of governor - cur_freq R: current frequency - polling_interval R: polling interval in ms given with devfreq profile W: update polling interval. - central_polling R: 1 if polling is managed by devfreq framework Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Reviewed-by: Mike Turquette <mturquette@ti.com> Acked-by: Kevin Hilman <khilman@ti.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> -- Documentation/ABI/testing/sysfs-class-devfreq | 44 ++++++++++++++++ drivers/devfreq/devfreq.c | 69 ++++++++++++++++++++++++++ 2 files changed, 113 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-class-devfreq
2011-10-01 22:19:28 +00:00
governor used by the corresponding devfreq object.
What: /sys/class/devfreq/.../cur_freq
Date: September 2011
Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
Description:
The /sys/class/devfreq/.../cur_freq shows the current
PM / devfreq: Add current freq callback in device profile Devfreq returns governor predicted frequency as current frequency via sysfs interface. But device may not support all frequencies that governor predicts. So add a callback in device profile to get current freq from driver. Also add a new sysfs node to expose governor predicted next target frequency. Signed-off-by: Rajagopal Venkat <rajagopal.venkat@linaro.org> Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2012-10-25 23:50:26 +00:00
frequency of the corresponding devfreq object. Same as
target_freq when get_cur_freq() is not implemented by
devfreq driver.
What: /sys/class/devfreq/.../target_freq
Date: September 2012
Contact: Rajagopal Venkat <rajagopal.venkat@linaro.org>
Description:
The /sys/class/devfreq/.../target_freq shows the next governor
predicted target frequency of the corresponding devfreq object.
PM / devfreq: Add common sysfs interfaces Device specific sysfs interface /sys/devices/.../power/devfreq_* - governor R: name of governor - cur_freq R: current frequency - polling_interval R: polling interval in ms given with devfreq profile W: update polling interval. - central_polling R: 1 if polling is managed by devfreq framework Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Reviewed-by: Mike Turquette <mturquette@ti.com> Acked-by: Kevin Hilman <khilman@ti.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> -- Documentation/ABI/testing/sysfs-class-devfreq | 44 ++++++++++++++++ drivers/devfreq/devfreq.c | 69 ++++++++++++++++++++++++++ 2 files changed, 113 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-class-devfreq
2011-10-01 22:19:28 +00:00
PM / devfreq: Add sysfs node for representing frequency transition information. This patch adds sysfs node which can be used to get information of frequency transition. It represents transition table which contains total number of transition of each freqeuncy state and time spent. It is inspired CPUFREQ's status driver. Signed-off-by: Jonghwa Lee <jonghwa3.lee@samsung.com> [Added Documentation/ABI entry, updated kernel-doc, and resolved merge conflict] Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
2012-08-23 11:00:46 +00:00
What: /sys/class/devfreq/.../trans_stat
Date: October 2012
Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
ABI: fix some syntax issues at the ABI database On those three files, the ABI representation described at README are violated. - at sysfs-bus-iio-proximity-as3935: a ':' character is missing after "What" - at sysfs-class-devfreq: there's a typo at Description - at sysfs-class-cxl, it is using the ":" character at a file preamble, causing it to be misinterpreted as a tag. - On the other files, instead of "What", they use "Where". Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Andrew Donnellan <ajd@linux.ibm.com> # cxl Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-14 02:04:07 +00:00
Description:
PM / devfreq: Add clearing transitions stats Add clearing transition table and time in states devfreq statistics by writing 0 (zero) to trans_stat file in devfreq sysfs. An example use is like following: echo 0 > /sys/class/devfreq/devfreqX/trans_stat Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com> [cw00.choi: Edit return value if entering the wrong value for reset and use arrary3_size() to get the size of 3-dimensional array] Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
2019-12-05 14:55:26 +00:00
This ABI shows or clears the statistics of devfreq behavior
on a specific device. It shows the time spent in each state
and the number of transitions between states.
PM / devfreq: Add sysfs node for representing frequency transition information. This patch adds sysfs node which can be used to get information of frequency transition. It represents transition table which contains total number of transition of each freqeuncy state and time spent. It is inspired CPUFREQ's status driver. Signed-off-by: Jonghwa Lee <jonghwa3.lee@samsung.com> [Added Documentation/ABI entry, updated kernel-doc, and resolved merge conflict] Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
2012-08-23 11:00:46 +00:00
In order to activate this ABI, the devfreq target device
driver should provide the list of available frequencies
PM / devfreq: Add clearing transitions stats Add clearing transition table and time in states devfreq statistics by writing 0 (zero) to trans_stat file in devfreq sysfs. An example use is like following: echo 0 > /sys/class/devfreq/devfreqX/trans_stat Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com> [cw00.choi: Edit return value if entering the wrong value for reset and use arrary3_size() to get the size of 3-dimensional array] Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
2019-12-05 14:55:26 +00:00
with its profile. If need to reset the statistics of devfreq
behavior on a specific device, enter 0(zero) to 'trans_stat'
docs: ABI: fix syntax to be parsed using ReST notation There are a number of new changes at the ABI files that cause them to produce warnings when generating ABI output. Fix them. Acked-by: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/55a89f423cf122982c462d257722e44d6ece4b36.1604042072.git.mchehab+huawei@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-10-30 07:40:47 +00:00
as following::
PM / devfreq: Add clearing transitions stats Add clearing transition table and time in states devfreq statistics by writing 0 (zero) to trans_stat file in devfreq sysfs. An example use is like following: echo 0 > /sys/class/devfreq/devfreqX/trans_stat Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com> [cw00.choi: Edit return value if entering the wrong value for reset and use arrary3_size() to get the size of 3-dimensional array] Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
2019-12-05 14:55:26 +00:00
echo 0 > /sys/class/devfreq/.../trans_stat
PM / devfreq: Add sysfs node for representing frequency transition information. This patch adds sysfs node which can be used to get information of frequency transition. It represents transition table which contains total number of transition of each freqeuncy state and time spent. It is inspired CPUFREQ's status driver. Signed-off-by: Jonghwa Lee <jonghwa3.lee@samsung.com> [Added Documentation/ABI entry, updated kernel-doc, and resolved merge conflict] Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
2012-08-23 11:00:46 +00:00
PM / devfreq: Fix buffer overflow in trans_stat_show Fix buffer overflow in trans_stat_show(). Convert simple snprintf to the more secure scnprintf with size of PAGE_SIZE. Add condition checking if we are exceeding PAGE_SIZE and exit early from loop. Also add at the end a warning that we exceeded PAGE_SIZE and that stats is disabled. Return -EFBIG in the case where we don't have enough space to write the full transition table. Also document in the ABI that this function can return -EFBIG error. Link: https://lore.kernel.org/all/20231024183016.14648-2-ansuelsmth@gmail.com/ Cc: stable@vger.kernel.org Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218041 Fixes: e552bbaf5b98 ("PM / devfreq: Add sysfs node for representing frequency transition information.") Signed-off-by: Christian Marangi <ansuelsmth@gmail.com> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
2023-10-24 18:30:15 +00:00
If the transition table is bigger than PAGE_SIZE, reading
this will return an -EFBIG error.
PM / devfreq: Add sysfs node to expose available frequencies devfreq governors such as ondemand are controlled by a min and max frequency, while governors like userspace governor allow us to set a specific frequency. However, for the same specific device, depending on the SoC, the available frequencies can vary. So expose the available frequencies as a snapshot over sysfs to allow informed decisions. This was inspired by cpufreq framework's equivalent for similar usage sysfs node: scaling_available_frequencies. Cc: Rajagopal Venkat <rajagopal.venkat@linaro.org> Cc: MyungJoo Ham <myungjoo.ham@samsung.com> Cc: Kyungmin Park <kyungmin.park@samsung.com> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Kevin Hilman <khilman@ti.com> Cc: linux-pm@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Nishanth Menon <nm@ti.com> Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
2012-10-26 00:48:59 +00:00
What: /sys/class/devfreq/.../available_frequencies
Date: October 2012
Contact: Nishanth Menon <nm@ti.com>
Description:
The /sys/class/devfreq/.../available_frequencies shows
the available frequencies of the corresponding devfreq object.
This is a snapshot of available frequencies and not limited
by the min/max frequency restrictions.
PM / devfreq: Add sysfs node to expose available governors Now that governor list can be variable, knowing the available governors is useful to be able to select a governor using relevant sysfs node. Cc: Rajagopal Venkat <rajagopal.venkat@linaro.org> Cc: MyungJoo Ham <myungjoo.ham@samsung.com> Cc: Kyungmin Park <kyungmin.park@samsung.com> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Kevin Hilman <khilman@ti.com> Cc: linux-pm@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Nishanth Menon <nm@ti.com> Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
2012-10-29 20:01:48 +00:00
What: /sys/class/devfreq/.../available_governors
Date: October 2012
Contact: Nishanth Menon <nm@ti.com>
Description:
The /sys/class/devfreq/.../available_governors shows
currently available governors in the system.
PM / devfreq: add comments and Documentation - Added missing ABI documents - Added comments to clarify the objectives of functions Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com> Acked-by: Nishanth Menon <nm@ti.com> Acked-by: Rajagopal Venkat <rajagopal.venkat@linaro.org>
2013-02-05 09:40:17 +00:00
What: /sys/class/devfreq/.../min_freq
Date: January 2013
Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
Description:
The /sys/class/devfreq/.../min_freq shows and stores
the minimum frequency requested by users. It is 0 if
the user does not care. min_freq overrides the
frequency requested by governors.
What: /sys/class/devfreq/.../max_freq
Date: January 2013
Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
Description:
The /sys/class/devfreq/.../max_freq shows and stores
the maximum frequency requested by users. It is 0 if
the user does not care. max_freq overrides the
frequency requested by governors and min_freq.
The max_freq overrides min_freq because max_freq may be
used to throttle devices to avoid overheating.
PM / devfreq: Add support delayed timer for polling mode Until now, the devfreq driver using polling mode like simple_ondemand governor have used only deferrable timer for reducing the redundant power consumption. It reduces the CPU wake-up from idle due to polling mode which check the status of Non-CPU device. But, it has a problem for Non-CPU device like DMC device with DMA operation. Some Non-CPU device need to do monitor continuously regardless of CPU state in order to decide the proper next status of Non-CPU device. So, add support the delayed timer for polling mode to support the repetitive monitoring. The devfreq driver and user can select the kind of timer on either deferrable and delayed timer. For example, change the timer type of DMC device based on Exynos5422-based Odroid-XU3 as following: - If want to use deferrable timer as following: echo deferrable > /sys/class/devfreq/10c20000.memory-controller/timer - If want to use delayed timer as following: echo delayed > /sys/class/devfreq/10c20000.memory-controller/timer Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Reviewed-by: Lukasz Luba <lukasz.luba@arm.com> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
2020-07-02 11:41:28 +00:00
PM / devfreq: Add governor attribute flag for specifc sysfs nodes DEVFREQ supports the default governors like performance, simple_ondemand and also allows the devfreq driver to add their own governor like tegra30-devfreq.c according to their requirement. In result, some sysfs attributes are useful or not useful. Prior to that the user can access all sysfs attributes regardless of the available attributes. So, clarify the access permission of sysfs attributes according to governor. When adding the devfreq governor, can specify the available attribute information by using DEVFREQ_GOV_ATTR_* constant variable. The user can read or write the sysfs attributes in accordance to the specified attributes. When adding the governor, can add the following attributes according to the governor feature. [Definition for speific sysfs attributes] - DEVFREQ_GOV_ATTR_POLLING_INTERVAL to update polling interval for timer. : /sys/class/devfreq/[devfreq dev name]/polling_interval - DEVFREQ_GOV_ATTR_TIMER to change the type of timer on either deferrable or dealyed timer. : /sys/class/devfreq/[devfreq dev name]/timer And all devfreq governors have to support the following common attributes. The common attributes are added to devfreq class by default. - governor - available_governors - available_frequencies - cur_freq - target_freq - min_freq - max_freq - trans_stat [Table of governor attribute flags for devfreq governors] ------------------------------------------------------------------------------ | simple | perfor | power | user | passive | tegra30 | ondemand | mance | save | space| | ------------------------------------------------------------------------------ governor | O | O | O | O | O | O available_governors | O | O | O | O | O | O available_frequencies | O | O | O | O | O | O cur_freq | O | O | O | O | O | O target_freq | O | O | O | O | O | O min_freq | O | O | O | O | O | O max_freq | O | O | O | O | O | O trans_stat | O | O | O | O | O | O -------------------------------------------------------- polling_interval | O | X | X | X | X | O timer | O | X | X | X | X | X ------------------------------------------------------------------------------ Reviewed-by: Dmitry Osipenko <digetx@gmail.com> Tested-by: Dmitry Osipenko <digetx@gmail.com> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
2020-07-03 08:20:27 +00:00
What: /sys/class/devfreq/.../polling_interval
Date: September 2011
Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
Description:
The /sys/class/devfreq/.../polling_interval shows and sets
the requested polling interval of the corresponding devfreq
object. The values are represented in ms. If the value is
less than 1 jiffy, it is considered to be 0, which means
no polling. This value is meaningless if the governor is
PM / devfreq: Remove the invalid description for get_target_freq First of all, no_central_polling was removed since commit 7e6fdd4bad03 ("PM / devfreq: Core updates to support devices which can idle") Secondly, get_target_freq() is not only called only with update_devfreq() notified by OPP now, but also min/max freq qos notifier. So remove this invalid description now to avoid confusing. Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
2021-03-23 07:20:09 +00:00
not polling.
PM / devfreq: Add governor attribute flag for specifc sysfs nodes DEVFREQ supports the default governors like performance, simple_ondemand and also allows the devfreq driver to add their own governor like tegra30-devfreq.c according to their requirement. In result, some sysfs attributes are useful or not useful. Prior to that the user can access all sysfs attributes regardless of the available attributes. So, clarify the access permission of sysfs attributes according to governor. When adding the devfreq governor, can specify the available attribute information by using DEVFREQ_GOV_ATTR_* constant variable. The user can read or write the sysfs attributes in accordance to the specified attributes. When adding the governor, can add the following attributes according to the governor feature. [Definition for speific sysfs attributes] - DEVFREQ_GOV_ATTR_POLLING_INTERVAL to update polling interval for timer. : /sys/class/devfreq/[devfreq dev name]/polling_interval - DEVFREQ_GOV_ATTR_TIMER to change the type of timer on either deferrable or dealyed timer. : /sys/class/devfreq/[devfreq dev name]/timer And all devfreq governors have to support the following common attributes. The common attributes are added to devfreq class by default. - governor - available_governors - available_frequencies - cur_freq - target_freq - min_freq - max_freq - trans_stat [Table of governor attribute flags for devfreq governors] ------------------------------------------------------------------------------ | simple | perfor | power | user | passive | tegra30 | ondemand | mance | save | space| | ------------------------------------------------------------------------------ governor | O | O | O | O | O | O available_governors | O | O | O | O | O | O available_frequencies | O | O | O | O | O | O cur_freq | O | O | O | O | O | O target_freq | O | O | O | O | O | O min_freq | O | O | O | O | O | O max_freq | O | O | O | O | O | O trans_stat | O | O | O | O | O | O -------------------------------------------------------- polling_interval | O | X | X | X | X | O timer | O | X | X | X | X | X ------------------------------------------------------------------------------ Reviewed-by: Dmitry Osipenko <digetx@gmail.com> Tested-by: Dmitry Osipenko <digetx@gmail.com> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
2020-07-03 08:20:27 +00:00
A list of governors that support the node:
- simple_ondmenad
- tegra_actmon
What: /sys/class/devfreq/.../userspace/set_freq
Date: September 2011
Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
Description:
The /sys/class/devfreq/.../userspace/set_freq shows and
sets the requested frequency for the devfreq object if
userspace governor is in effect.
A list of governors that support the node:
- userspace
PM / devfreq: Add support delayed timer for polling mode Until now, the devfreq driver using polling mode like simple_ondemand governor have used only deferrable timer for reducing the redundant power consumption. It reduces the CPU wake-up from idle due to polling mode which check the status of Non-CPU device. But, it has a problem for Non-CPU device like DMC device with DMA operation. Some Non-CPU device need to do monitor continuously regardless of CPU state in order to decide the proper next status of Non-CPU device. So, add support the delayed timer for polling mode to support the repetitive monitoring. The devfreq driver and user can select the kind of timer on either deferrable and delayed timer. For example, change the timer type of DMC device based on Exynos5422-based Odroid-XU3 as following: - If want to use deferrable timer as following: echo deferrable > /sys/class/devfreq/10c20000.memory-controller/timer - If want to use delayed timer as following: echo delayed > /sys/class/devfreq/10c20000.memory-controller/timer Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Reviewed-by: Lukasz Luba <lukasz.luba@arm.com> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
2020-07-02 11:41:28 +00:00
What: /sys/class/devfreq/.../timer
Date: July 2020
Contact: Chanwoo Choi <cw00.choi@samsung.com>
Description:
This ABI shows and stores the kind of work timer by users.
This work timer is used by devfreq workqueue in order to
monitor the device status such as utilization. The user
can change the work timer on runtime according to their demand
docs: ABI: fix syntax to be parsed using ReST notation There are a number of new changes at the ABI files that cause them to produce warnings when generating ABI output. Fix them. Acked-by: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/55a89f423cf122982c462d257722e44d6ece4b36.1604042072.git.mchehab+huawei@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-10-30 07:40:47 +00:00
as following::
PM / devfreq: Add support delayed timer for polling mode Until now, the devfreq driver using polling mode like simple_ondemand governor have used only deferrable timer for reducing the redundant power consumption. It reduces the CPU wake-up from idle due to polling mode which check the status of Non-CPU device. But, it has a problem for Non-CPU device like DMC device with DMA operation. Some Non-CPU device need to do monitor continuously regardless of CPU state in order to decide the proper next status of Non-CPU device. So, add support the delayed timer for polling mode to support the repetitive monitoring. The devfreq driver and user can select the kind of timer on either deferrable and delayed timer. For example, change the timer type of DMC device based on Exynos5422-based Odroid-XU3 as following: - If want to use deferrable timer as following: echo deferrable > /sys/class/devfreq/10c20000.memory-controller/timer - If want to use delayed timer as following: echo delayed > /sys/class/devfreq/10c20000.memory-controller/timer Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Reviewed-by: Lukasz Luba <lukasz.luba@arm.com> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
2020-07-02 11:41:28 +00:00
echo deferrable > /sys/class/devfreq/.../timer
echo delayed > /sys/class/devfreq/.../timer
PM / devfreq: Add governor attribute flag for specifc sysfs nodes DEVFREQ supports the default governors like performance, simple_ondemand and also allows the devfreq driver to add their own governor like tegra30-devfreq.c according to their requirement. In result, some sysfs attributes are useful or not useful. Prior to that the user can access all sysfs attributes regardless of the available attributes. So, clarify the access permission of sysfs attributes according to governor. When adding the devfreq governor, can specify the available attribute information by using DEVFREQ_GOV_ATTR_* constant variable. The user can read or write the sysfs attributes in accordance to the specified attributes. When adding the governor, can add the following attributes according to the governor feature. [Definition for speific sysfs attributes] - DEVFREQ_GOV_ATTR_POLLING_INTERVAL to update polling interval for timer. : /sys/class/devfreq/[devfreq dev name]/polling_interval - DEVFREQ_GOV_ATTR_TIMER to change the type of timer on either deferrable or dealyed timer. : /sys/class/devfreq/[devfreq dev name]/timer And all devfreq governors have to support the following common attributes. The common attributes are added to devfreq class by default. - governor - available_governors - available_frequencies - cur_freq - target_freq - min_freq - max_freq - trans_stat [Table of governor attribute flags for devfreq governors] ------------------------------------------------------------------------------ | simple | perfor | power | user | passive | tegra30 | ondemand | mance | save | space| | ------------------------------------------------------------------------------ governor | O | O | O | O | O | O available_governors | O | O | O | O | O | O available_frequencies | O | O | O | O | O | O cur_freq | O | O | O | O | O | O target_freq | O | O | O | O | O | O min_freq | O | O | O | O | O | O max_freq | O | O | O | O | O | O trans_stat | O | O | O | O | O | O -------------------------------------------------------- polling_interval | O | X | X | X | X | O timer | O | X | X | X | X | X ------------------------------------------------------------------------------ Reviewed-by: Dmitry Osipenko <digetx@gmail.com> Tested-by: Dmitry Osipenko <digetx@gmail.com> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
2020-07-03 08:20:27 +00:00
A list of governors that support the node:
- simple_ondemand
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