linux-stable.git/drivers/devfreq/devfreq.c, branch v5.5.7

PM / devfreq: Add debugfs support with devfreq_summary file

2020-02-24T07:38:33+00:00

[ Upstream commit 490a421bc575d1bf391a6ad5b582dcfbd0037724 ]

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 
Signed-off-by: Sasha Levin

PM / devfreq: Change time stats to 64-bit

2020-02-24T07:38:21+00:00

[ Upstream commit b76b3479dab948bea0a98b6d263eb56d8f358528 ]

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 
Signed-off-by: Sasha Levin

PM / devfreq: Add new name attribute for sysfs

2020-02-04T18:18:01+00:00

commit 2fee1a7cc6b1ce6634bb0f025be2c94a58dfa34d upstream.

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 
Signed-off-by: Greg Kroah-Hartman

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

PM / devfreq: Introduce get_freq_range helper

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

Moving handling of min/max freq to a single function and call it from
update_devfreq and for printing min/max freq values in sysfs.

This changes the behavior of out-of-range min_freq/max_freq: clamping
is now done at evaluation time. This means that if an out-of-range
constraint is imposed by sysfs and it later becomes valid then it will
be enforced.

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

PM / devfreq: Set scaling_max_freq to max on OPP notifier error

2019-12-09T03:19:15+00:00

The devfreq_notifier_call functions will update scaling_min_freq and
scaling_max_freq when the OPP table is updated.

If fetching the maximum frequency fails then scaling_max_freq remains
set to zero which is confusing. Set to ULONG_MAX instead so we don't
need special handling for this case in other places.

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

PM / devfreq: Fix devfreq_notifier_call returning errno

2019-12-09T03:19:15+00:00

Notifier callbacks shouldn't return negative errno but one of the
NOTIFY_OK/DONE/BAD values.

The OPP core will ignore return values from notifiers but returning a
value that matches NOTIFY_STOP_MASK will stop the notification chain.

Fix by always returning NOTIFY_OK.

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

PM / devfreq: Add missing locking while setting suspend_freq

2019-11-29T11:50:34+00:00

Commit 2abb0d5268ae ("PM / devfreq: Lock devfreq in trans_stat_show")
revealed a missing locking while calling devfreq_update_status() function
during suspend/resume cycle.

Code analysis revealed that devfreq_set_target() function was called
without needed locks held for setting device specific suspend_freq if such
has been defined. This patch fixes that by adding the needed locking, what
fixes following kernel warning on Exynos4412-based OdroidU3 board during
system suspend:

PM: suspend entry (deep)
Filesystems sync: 0.002 seconds
Freezing user space processes ... (elapsed 0.001 seconds) done.
OOM killer disabled.
Freezing remaining freezable tasks ... (elapsed 0.001 seconds) done.
------------[ cut here ]------------
WARNING: CPU: 2 PID: 1385 at drivers/devfreq/devfreq.c:204 devfreq_update_status+0xc0/0x188
Modules linked in:
CPU: 2 PID: 1385 Comm: rtcwake Not tainted 5.4.0-rc6-next-20191111 #6848
Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
[] (unwind_backtrace) from [] (show_stack+0x10/0x14)
[] (show_stack) from [] (dump_stack+0xb4/0xe0)
[] (dump_stack) from [] (__warn+0xf4/0x10c)
[] (__warn) from [] (warn_slowpath_fmt+0xb0/0xb8)
[] (warn_slowpath_fmt) from [] (devfreq_update_status+0xc0/0x188)
[] (devfreq_update_status) from [] (devfreq_set_target+0xb0/0x15c)
[] (devfreq_set_target) from [] (devfreq_suspend+0x2c/0x64)
[] (devfreq_suspend) from [] (dpm_suspend+0xa4/0x57c)
[] (dpm_suspend) from [] (dpm_suspend_start+0x98/0xa0)
[] (dpm_suspend_start) from [] (suspend_devices_and_enter+0xec/0xc74)
[] (suspend_devices_and_enter) from [] (pm_suspend+0x340/0x410)
[] (pm_suspend) from [] (state_store+0x6c/0xc8)
[] (state_store) from [] (kernfs_fop_write+0x10c/0x228)
[] (kernfs_fop_write) from [] (__vfs_write+0x30/0x1d0)
[] (__vfs_write) from [] (vfs_write+0xa4/0x180)
[] (vfs_write) from [] (ksys_write+0x60/0xd8)
[] (ksys_write) from [] (ret_fast_syscall+0x0/0x28)
Exception stack(0xed3d7fa8 to 0xed3d7ff0)
...
irq event stamp: 9667
hardirqs last  enabled at (9679): [] _raw_spin_unlock_irq+0x20/0x58
hardirqs last disabled at (9698): [] __schedule+0xd8/0x818
softirqs last  enabled at (9694): [] __do_softirq+0x4fc/0x5fc
softirqs last disabled at (9719): [] irq_exit+0x16c/0x170
---[ end trace 41ac5b57d046bdbc ]---
------------[ cut here ]------------

Signed-off-by: Marek Szyprowski 
Acked-by: Chanwoo Choi 
Signed-off-by: Rafael J. Wysocki