linux.git/drivers/devfreq/devfreq.c, branch v5.6-rc2

PM / devfreq: Add debugfs support with devfreq_summary file

2020-01-16T10:14:49+00:00

Add debugfs interface to provide debugging information of devfreq device.
It contains 'devfreq_summary' entry to show the summary of registered
devfreq devices as following and the additional debugfs file will be added.
- /sys/kernel/debug/devfreq/devfreq_summary

[Detailed description of each field of 'devfreq_summary' debugfs file]
- dev_name	: Device name of h/w
- dev		: Device name made by devfreq core
- parent_dev	: If devfreq device uses the passive governor,
		  show parent devfreq device name. Otherwise, show 'null'.
- governor	: Devfreq governor name
- polling_ms	: If devfreq device uses the simple_ondemand governor,
		  polling_ms is necessary for the period. (unit: millisecond)
- cur_freq_Hz	: Current frequency (unit: Hz)
- min_freq_Hz	: Minimum frequency (unit: Hz)
- max_freq_Hz	: Maximum frequency (unit: Hz)

[For example on Exynos5422-based Odroid-XU3 board]
$ cat /sys/kernel/debug/devfreq/devfreq_summary
dev_name                       dev        parent_dev governor        polling_ms  cur_freq_Hz  min_freq_Hz  max_freq_Hz
------------------------------ ---------- ---------- --------------- ---------- ------------ ------------ ------------
10c20000.memory-controller     devfreq0   null       simple_ondemand          0    165000000    165000000    825000000
soc:bus_wcore                  devfreq1   null       simple_ondemand         50    532000000     88700000    532000000
soc:bus_noc                    devfreq2   devfreq1   passive                  0    111000000     66600000    111000000
soc:bus_fsys_apb               devfreq3   devfreq1   passive                  0    222000000    111000000    222000000
soc:bus_fsys                   devfreq4   devfreq1   passive                  0    200000000     75000000    200000000
soc:bus_fsys2                  devfreq5   devfreq1   passive                  0    200000000     75000000    200000000
soc:bus_mfc                    devfreq6   devfreq1   passive                  0    333000000     83250000    333000000
soc:bus_gen                    devfreq7   devfreq1   passive                  0    266000000     88700000    266000000
soc:bus_peri                   devfreq8   devfreq1   passive                  0     66600000     66600000     66600000
soc:bus_g2d                    devfreq9   devfreq1   passive                  0    333000000     83250000    333000000
soc:bus_g2d_acp                devfreq10  devfreq1   passive                  0    266000000     66500000    266000000
soc:bus_jpeg                   devfreq11  devfreq1   passive                  0    300000000     75000000    300000000
soc:bus_jpeg_apb               devfreq12  devfreq1   passive                  0    166500000     83250000    166500000
soc:bus_disp1_fimd             devfreq13  devfreq1   passive                  0    200000000    120000000    200000000
soc:bus_disp1                  devfreq14  devfreq1   passive                  0    300000000    120000000    300000000
soc:bus_gscl_scaler            devfreq15  devfreq1   passive                  0    300000000    150000000    300000000
soc:bus_mscl                   devfreq16  devfreq1   passive                  0    666000000     84000000    666000000

[lkp: Reported the build error]
Reported-by: kbuild test robot 
Signed-off-by: Chanwoo Choi

PM / devfreq: Fix multiple kernel-doc warnings

2019-12-30T00:59:06+00:00

Fix kernel-doc warnings in devfreq files.
Also fix a typo.

Signed-off-by: Randy Dunlap 
Signed-off-by: Chanwoo Choi

PM / devfreq: Move declaration of DEVICE_ATTR_RW(min_freq)

2019-12-30T00:59:05+00:00

Declaration of DEVICE_ATTR_RW(min_freq) is placed after function
max_freq_store. Move it to the correct place after min_freq_show.

Signed-off-by: Kamil Konieczny 
Signed-off-by: Chanwoo Choi

PM / devfreq: Move statistics to separate struct devfreq_stats

2019-12-30T00:59:05+00:00

Count time and transitions between devfreq frequencies in separate
struct devfreq_stats for improved code readability and maintenance.

Signed-off-by: Kamil Konieczny 
Reviewed-by: Matthias Kaehlcke 
[cw00.choi: Fix the merge conflict in trasn_stat_store
 and use 'devfreq->stats.*' style for consistent coding style
 and restore the clean-up code of 'devfreq->profile->*']
Signed-off-by: Chanwoo Choi

PM / devfreq: Add clearing transitions stats

2019-12-30T00:59:05+00:00

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 
[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

PM / devfreq: Change time stats to 64-bit

2019-12-30T00:59:05+00:00

Change time stats counting to bigger type by using 64-bit jiffies.
This will make devfreq stats code look similar to cpufreq stats and
prevents overflow (for HZ = 1000 after 49.7 days).

Signed-off-by: Kamil Konieczny 
Acked-by: Chanwoo Choi 
Signed-off-by: Chanwoo Choi

PM / devfreq: Add new name attribute for sysfs

2019-12-30T00:59:05+00:00

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

PM / devfreq: Use PM QoS for sysfs min/max_freq

2019-12-09T03:19:16+00:00

Switch the handling of min_freq and max_freq from sysfs to use the
dev_pm_qos_request interface.

Since PM QoS handles frequencies as kHz this change reduces the
precision of min_freq and max_freq. This shouldn't introduce problems
because frequencies which are not an integer number of kHz are likely
not an integer number of Hz either.

Try to ensure compatibility by rounding min values down and rounding
max values up.

Signed-off-by: Leonard Crestez 
Acked-by: Chanwoo Choi 
Reviewed-by: Matthias Kaehlcke 
Tested-by: Matthias Kaehlcke 
[cw00.choi: Return -EAGAIN instead of -EINVAL if dev_pm_qos is inactive]
Signed-off-by: Chanwoo Choi

PM / devfreq: Add PM QoS support

2019-12-09T03:19:16+00:00

Register notifiers with the PM QoS framework in order to respond to
requests for DEV_PM_QOS_MIN_FREQUENCY and DEV_PM_QOS_MAX_FREQUENCY.

No notifiers are added by this patch but PM QoS constraints can be
imposed externally (for example from other devices).

Signed-off-by: Leonard Crestez 
Acked-by: Chanwoo Choi 
Reviewed-by: Matthias Kaehlcke 
Tested-by: Matthias Kaehlcke 
Signed-off-by: Chanwoo Choi

PM / devfreq: Don't fail devfreq_dev_release if not in list

2019-12-09T03:19:16+00:00

Right now devfreq_dev_release will print a warning and abort the rest of
the cleanup if the devfreq instance is not part of the global
devfreq_list. But this is a valid scenario, for example it can happen if
the governor can't be found or on any other init error that happens
after device_register.

Initialize devfreq->node to an empty list head in devfreq_add_device so
that list_del becomes a safe noop inside devfreq_dev_release and we can
continue the rest of the cleanup.

Signed-off-by: Leonard Crestez 
Reviewed-by: Matthias Kaehlcke 
Reviewed-by: Chanwoo Choi 
Signed-off-by: Chanwoo Choi