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Make the comment in blocking_notifier_call_chain() easier to
understand.
Signed-off-by: Tang Yizhou <tangyizhou@huawei.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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When I hot added a CPU, I found 'cpufreq' directory was not created
below /sys/devices/system/cpu/cpuX/.
It is because get_cpu_device() failed in add_cpu_dev_symlink().
cpufreq_add_dev() is the .add_dev callback of a CPU subsys interface.
It will be called when the CPU device registered into the system.
The call chain is as follows:
register_cpu()
->device_register()
->device_add()
->bus_probe_device()
->cpufreq_add_dev()
But only after the CPU device has been registered, we can get the
CPU device by get_cpu_device(), otherwise it will return NULL.
Since we already have the CPU device in cpufreq_add_dev(), pass
it to add_cpu_dev_symlink().
I noticed that the 'kobj' of the CPU device has been added into
the system before cpufreq_add_dev().
Fixes: 2f0ba790df51 ("cpufreq: Fix creation of symbolic links to policy directories")
Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Let the governors schedutil, conservative and ondemand to work, if possible
on efficient frequencies only.
Signed-off-by: Vincent Donnefort <vincent.donnefort@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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This newly introduced flag can be applied by a governor to a CPUFreq
relation, when looking for a frequency within the policy table. The
resolution would then only walk through efficient frequencies.
Even with the flag set, the policy max limit will still be honoured. If no
efficient frequencies can be found within the limits of the policy, an
inefficient one would be returned.
Signed-off-by: Vincent Donnefort <vincent.donnefort@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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When applying the policy min/max limits, the requested frequency is
simply clamped to not be out of range. It means, however, if one of the
boundaries isn't an available frequency, the frequency resolution can
return a value out of those limits, depending on the relation used.
e.g. freq{0,1,2} being available frequencies.
freq0 policy->min freq1 policy->max freq2
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17kHz 18kHz 19kHz 20kHz 21kHz
__resolve_freq(21kHz, CPUFREQ_RELATION_L) -> 21kHz (out of bounds)
__resolve_freq(17kHz, CPUFREQ_RELATION_H) -> 17kHz (out of bounds)
If, during the policy init, we resolve the requested min/max to existing
frequencies, we ensure that any CPUFREQ_RELATION_* would resolve to a
frequency which is inside the policy min/max range.
Making the policy limits rigid helps to introduce the inefficient
frequencies support. Resolving an inefficient frequency to an efficient
one should not transgress policy->max (which can be set for thermal
reason) and having a value we can trust simplify this comparison.
Signed-off-by: Vincent Donnefort <vincent.donnefort@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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This isn't used anymore, get rid of it.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/vireshk/pm
Pull ARM cpufreq driver changes for v5.15 from Viresh Kumar:
"This contains:
- Update cpufreq-dt blocklist with more platforms (Bjorn Andersson).
- Allow freq changes from any CPU for qcom-hw driver (Taniya Das).
- Add DSVS interrupt's support for qcom-hw driver (Thara Gopinath).
- A new callback (->register_em()) to register EM at a more convenient
point of time."
* 'cpufreq/arm/linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/vireshk/pm:
cpufreq: qcom-hw: Set dvfs_possible_from_any_cpu cpufreq driver flag
cpufreq: blocklist more Qualcomm platforms in cpufreq-dt-platdev
cpufreq: qcom-cpufreq-hw: Add dcvs interrupt support
cpufreq: scmi: Use .register_em() to register with energy model
cpufreq: vexpress: Use .register_em() to register with energy model
cpufreq: scpi: Use .register_em() to register with energy model
cpufreq: qcom-cpufreq-hw: Use .register_em() to register with energy model
cpufreq: omap: Use .register_em() to register with energy model
cpufreq: mediatek: Use .register_em() to register with energy model
cpufreq: imx6q: Use .register_em() to register with energy model
cpufreq: dt: Use .register_em() to register with energy model
cpufreq: Add callback to register with energy model
cpufreq: vexpress: Set CPUFREQ_IS_COOLING_DEV flag
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Many cpufreq drivers register with the energy model for each policy and
do exactly the same thing. Follow the footsteps of thermal-cooling, to
get it done from the cpufreq core itself.
Provide a new callback, which will be called, if present, by the cpufreq
core at the right moment (more on that in the code's comment). Also
provide a generic implementation that uses dev_pm_opp_of_register_em().
This also allows us to register with the EM at a later point of time,
compared to ->init(), from where the EM core can access cpufreq policy
directly using cpufreq_cpu_get() type of helpers and perform other work,
like marking few frequencies inefficient, this will be done separately.
Reviewed-by: Quentin Perret <qperret@google.com>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
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The functions get_online_cpus() and put_online_cpus() have been
deprecated during the CPU hotplug rework. They map directly to
cpus_read_lock() and cpus_read_unlock().
Replace deprecated CPU-hotplug functions with the official version.
The behavior remains unchanged.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Commit e3c062360870 ("cpufreq: add cpufreq_driver_resolve_freq()")
introduced this callback, back in 2016, for drivers that provide the
->target() callback.
The kernel hasn't seen a single user of it in the past 5 years and
it is not likely to be used any time soon.
Remove it for now.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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__cpufreq_driver_target() open codes cpufreq_driver_resolve_freq(), lets
make the former reuse the later.
Separate out __resolve_freq() to accept relation as well as an argument
and use it at both the locations.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Now that all users of ->stop_cpu() have been migrated to using other
callbacks, drop it from the core.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Minor edits in the subject and changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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In the CPU removal path the ->offline() callback provided by the
driver is always invoked before ->exit(), but in the cpufreq_online()
error path it is not, so ->exit() is expected to somehow know the
context in which it has been called and act accordingly.
That is less than straightforward, so make cpufreq_online() invoke
the driver's ->offline() callback, if present, on errors before
->exit() too.
This only potentially affects intel_pstate.
Fixes: 91a12e91dc39 ("cpufreq: Allow light-weight tear down and bring up of CPUs")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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Macro 'for_each_policy' has become unused since commit
f963735a3ca3 ("cpufreq: Create for_each_{in}active_policy()"), so
remove it.
Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Change 'Terget' to 'Target'.
Should be Target.
Signed-off-by: Yue Hu <huyue2@yulong.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Subject edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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During cpufreq driver's registration, if the ->init() callback for all
the CPUs fail then there is not much point in keeping the driver around
as it will only account for more of unnecessary noise, for example
cpufreq core will try to suspend/resume the driver which never got
registered properly.
The removal of such a driver is avoided if the driver carries the
CPUFREQ_STICKY flag. This was added way back [1] in 2004 and perhaps no
one should ever need it now. A lot of drivers do set this flag, probably
because they just copied it from other drivers.
This was added earlier for some platforms [2] because their cpufreq
drivers were getting registered before the CPUs were registered with
subsys framework. And hence they used to fail.
The same isn't true anymore though. The current code flow in the kernel
is:
start_kernel()
-> kernel_init()
-> kernel_init_freeable()
-> do_basic_setup()
-> driver_init()
-> cpu_dev_init()
-> subsys_system_register() //For CPUs
-> do_initcalls()
-> cpufreq_register_driver()
Clearly, the CPUs will always get registered with subsys framework
before any cpufreq driver can get probed. Remove the flag and update the
relevant drivers.
Link: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git/commit/include/linux/cpufreq.h?id=7cc9f0d9a1ab04cedc60d64fd8dcf7df224a3b4d # [1]
Link: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git/commit/arch/arm/mach-sa1100/cpu-sa1100.c?id=f59d3bbe35f6268d729f51be82af8325d62f20f5 # [2]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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First off, some cpufreq drivers (eg. intel_pstate) can pass hints
beyond the current target frequency to the hardware and there are no
provisions for doing that in the cpufreq framework. In particular,
today the driver has to assume that it should not allow the frequency
to fall below the one requested by the governor (or the required
capacity may not be provided) which may not be the case and which may
lead to excessive energy usage in some scenarios.
Second, the hints passed by these drivers to the hardware need not be
in terms of the frequency, so representing the utilization numbers
coming from the scheduler as frequency before passing them to those
drivers is not really useful.
Address the two points above by adding a special-purpose replacement
for the ->fast_switch callback, called ->adjust_perf, allowing the
governor to pass abstract performance level (rather than frequency)
values for the minimum (required) and target (desired) performance
along with the CPU capacity to compare them to.
Also update the schedutil governor to use the new callback instead
of ->fast_switch if present and if the utilization mertics are
frequency-invariant (that is requisite for the direct mapping
between the utilization and the CPU performance levels to be a
reasonable approximation).
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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Make cpufreq_online() return negative error codes on all errors that
cause the policy to be destroyed, as appropriate.
Signed-off-by: Wang ShaoBo <bobo.shaobowang@huawei.com>
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Fix up the remaining kerneldoc comments that don't adhere to the
expected format and clarify some of them a bit.
No functional changes.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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Add a new field to be set when the CPUFREQ_GOV_STRICT_TARGET flag is
set for the current governor to struct cpufreq_policy, so that the
drivers needing to check CPUFREQ_GOV_STRICT_TARGET do not have to
access the governor object during every frequency transition.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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A new cpufreq governor flag will be added subsequently, so replace
the bool dynamic_switching fleid in struct cpufreq_governor with a
flags field and introduce CPUFREQ_GOV_DYNAMIC_SWITCHING to set for
the "dynamic switching" governors instead of it.
No intentional functional impact.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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The restore_freq field in struct cpufreq_policy is only used by
__target_index() in one place and a local variable in that function
may as well be used instead of it, so drop it and modify
__target_index() accordingly.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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Add a helper function to test the flags of the cpufreq driver in use
againt a given flags mask.
In particular, this will be needed to test the
CPUFREQ_NEED_UPDATE_LIMITS cpufreq driver flag in the schedutil
governor.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Generally, a cpufreq driver may need to update some internal upper
and lower frequency boundaries on policy max and min changes,
respectively, but currently this does not work if the target
frequency does not change along with the policy limit.
Namely, if the target frequency does not change along with the
policy min or max, the "target_freq == policy->cur" check in
__cpufreq_driver_target() prevents driver callbacks from being
invoked and they do not even have a chance to update the
corresponding internal boundary.
This particularly affects the "powersave" and "performance"
governors that always set the target frequency to one of the
policy limits and it never changes when the other limit is updated.
To allow cpufreq the drivers needing to update internal frequency
boundaries on policy limits changes to avoid this issue, introduce
a new driver flag, CPUFREQ_NEED_UPDATE_LIMITS, that (when set) will
neutralize the check mentioned above.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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The cpufreq core checks if the frequency programmed by the bootloaders
is not listed in the freq table and programs one from the table in such
a case. This is done only if the driver has set the
CPUFREQ_NEED_INITIAL_FREQ_CHECK flag.
Currently we print two separate messages, with almost the same content,
and do this with a pr_warn() which may be a bit too much as the driver
only asked us to check this as it expected this to be the case. Lower
down the severity of the print message by switching to pr_info() instead
and print a single message only.
Reported-by: Sumit Gupta <sumitg@nvidia.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Sumit Gupta <sumitg@nvidia.com>
Tested-by: Sumit Gupta <sumitg@nvidia.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Compared to other arch_* functions, arch_set_freq_scale() has an atypical
weak definition that can be replaced by a strong architecture specific
implementation.
The more typical support for architectural functions involves defining
an empty stub in a header file if the symbol is not already defined in
architecture code. Some examples involve:
- #define arch_scale_freq_capacity topology_get_freq_scale
- #define arch_scale_freq_invariant topology_scale_freq_invariant
- #define arch_scale_cpu_capacity topology_get_cpu_scale
- #define arch_update_cpu_topology topology_update_cpu_topology
- #define arch_scale_thermal_pressure topology_get_thermal_pressure
- #define arch_set_thermal_pressure topology_set_thermal_pressure
Bring arch_set_freq_scale() in line with these functions by renaming it to
topology_set_freq_scale() in the arch topology driver, and by defining the
arch_set_freq_scale symbol to point to the new function for arm and arm64.
While there are other users of the arch_topology driver, this patch defines
arch_set_freq_scale for arm and arm64 only, due to their existing
definitions of arch_scale_freq_capacity. This is the getter function of the
frequency invariance scale factor and without a getter function, the
setter function - arch_set_freq_scale() has not purpose.
Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Sudeep Holla <sudeep.holla@arm.com> (BL_SWITCHER and topology parts)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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The cpufreq core handles the updates to policy->cur and recording of
cpufreq trace events for all the governors except schedutil's fast
switch case.
Move that as well to cpufreq core for consistency and readability.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Now that all the blockers are gone for enabling stats in fast-switching
case, enable it.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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The passed cpumask arguments to arch_set_freq_scale() and
arch_freq_counters_available() are only iterated over, so reflect this
in the prototype. This also allows to pass system cpumasks like
cpu_online_mask without getting a warning.
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Now that the update of the FI scale factor is done in cpufreq core for
selected functions - target(), target_index() and fast_switch(),
we can provide feedback to the task scheduler and architecture code
on whether cpufreq supports FI.
For this purpose provide an external function to expose whether the
cpufreq drivers support FI, by using a static key.
The logic behind the enablement of cpufreq-based invariance is as
follows:
- cpufreq-based invariance is disabled by default
- cpufreq-based invariance is enabled if any of the callbacks
above is implemented while the unsupported setpolicy() is not
The cpufreq_supports_freq_invariance() function only returns whether
cpufreq is instrumented with the arch_set_freq_scale() calls that
result in support for frequency invariance. Due to the lack of knowledge
on whether the implementation of arch_set_freq_scale() actually results
in the setting of a scale factor based on cpufreq information, it is up
to the architecture code to ensure the setting and provision of the
scale factor to the scheduler.
Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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To properly scale its per-entity load-tracking signals, the task scheduler
needs to be given a frequency scale factor, i.e. some image of the current
frequency the CPU is running at. Currently, this scale can be computed
either by using counters (APERF/MPERF on x86, AMU on arm64), or by
piggy-backing on the frequency selection done by cpufreq.
For the latter, drivers have to explicitly set the scale factor
themselves, despite it being purely boiler-plate code: the required
information depends entirely on the kind of frequency switch callback
implemented by the driver, i.e. either of: target_index(), target(),
fast_switch() and setpolicy().
The fitness of those callbacks with regard to driving the Frequency
Invariance Engine (FIE) is studied below:
target_index()
==============
Documentation states that the chosen frequency "must be determined by
freq_table[index].frequency". It isn't clear if it *has* to be that
frequency, or if it can use that frequency value to do some computation
that ultimately leads to a different frequency selection. All drivers
go for the former, while the vexpress-spc-cpufreq has an atypical
implementation which is handled separately.
Therefore, the hook works on the assumption the core can use
freq_table[index].frequency.
target()
=======
This has been flagged as deprecated since:
commit 9c0ebcf78fde ("cpufreq: Implement light weight ->target_index() routine")
It also doesn't have that many users:
gx-suspmod.c:439: .target = cpufreq_gx_target,
s3c24xx-cpufreq.c:428: .target = s3c_cpufreq_target,
intel_pstate.c:2528: .target = intel_cpufreq_target,
cppc_cpufreq.c:401: .target = cppc_cpufreq_set_target,
cpufreq-nforce2.c:371: .target = nforce2_target,
sh-cpufreq.c:163: .target = sh_cpufreq_target,
pcc-cpufreq.c:573: .target = pcc_cpufreq_target,
Similarly to the path taken for target_index() calls in the cpufreq core
during a frequency change, all of the drivers above will mark the end of a
frequency change by a call to cpufreq_freq_transition_end().
Therefore, cpufreq_freq_transition_end() can be used as the location for
the arch_set_freq_scale() call to potentially inform the scheduler of the
frequency change.
This change maintains the previous functionality for the drivers that
implement the target_index() callback, while also adding support for the
few drivers that implement the deprecated target() callback.
fast_switch()
=============
This callback *has* to return the frequency that was selected.
setpolicy()
===========
This callback does not have any designated way of informing what was the
end choice. But there are only two drivers using setpolicy(), and none
of them have current FIE support:
drivers/cpufreq/longrun.c:281: .setpolicy = longrun_set_policy,
drivers/cpufreq/intel_pstate.c:2215: .setpolicy = intel_pstate_set_policy,
The intel_pstate is known to use counter-driven frequency invariance.
Conclusion
==========
Given that the significant majority of current FIE enabled drivers use
callbacks that lend themselves to triggering the setting of the FIE scale
factor in a generic way, move the invariance setter calls to cpufreq core.
As a result of setting the frequency scale factor in cpufreq core, after
callbacks that lend themselves to trigger it, remove this functionality
from the driver side.
To be noted that despite marking a successful frequency change, many
cpufreq drivers will consider the new frequency as the requested
frequency, although this is might not be the one granted by the hardware.
Therefore, the call to arch_set_freq_scale() is a "best effort" one, and
it is up to the architecture if the new frequency is used in the new
frequency scale factor setting (determined by the implementation of
arch_set_freq_scale()) or eventually used by the scheduler (determined
by the implementation of arch_scale_freq_capacity()). The architecture
is in a better position to decide if it has better methods to obtain
more accurate information regarding the current frequency and use that
information instead (for example, the use of counters).
Also, the implementation to arch_set_freq_scale() will now have to handle
error conditions (current frequency == 0) in order to prevent the
overhead in cpufreq core when the default arch_set_freq_scale()
implementation is used.
Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
Suggested-by: Valentin Schneider <valentin.schneider@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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"cpufreq_driver" is guaranteed to be valid here, no need to check it
here.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Allow intel_pstate to work in the passive mode with HWP enabled and
make it set the HWP minimum performance limit (HWP floor) to the
P-state value given by the target frequency supplied by the cpufreq
governor, so as to prevent the HWP algorithm and the CPU scheduler
from working against each other, at least when the schedutil governor
is in use, and update the intel_pstate documentation accordingly.
Among other things, this allows utilization clamps to be taken
into account, at least to a certain extent, when intel_pstate is
in use and makes it more likely that sufficient capacity for
deadline tasks will be provided.
After this change, the resulting behavior of an HWP system with
intel_pstate in the passive mode should be close to the behavior
of the analogous non-HWP system with intel_pstate in the passive
mode, except that the HWP algorithm is generally allowed to make the
CPU run at a frequency above the floor P-state set by intel_pstate in
the entire available range of P-states, while without HWP a CPU can
run in a P-state above the requested one if the latter falls into the
range of turbo P-states (referred to as the turbo range) or if the
P-states of all CPUs in one package are coordinated with each other
at the hardware level.
[Note that in principle the HWP floor may not be taken into account
by the processor if it falls into the turbo range, in which case the
processor has a license to choose any P-state, either below or above
the HWP floor, just like a non-HWP processor in the case when the
target P-state falls into the turbo range.]
With this change applied, intel_pstate in the passive mode assumes
complete control over the HWP request MSR and concurrent changes of
that MSR (eg. via the direct MSR access interface) are overridden by
it.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Reviewed-by: Francisco Jerez <currojerez@riseup.net>
|
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git://git.kernel.org/pub/scm/linux/kernel/git/vireshk/pm
Pull ARM cpufreq driver changes for v5.9-rc1 from Viresh Kumar:
"Here are the details:
- Adaptive voltage scaling (AVS) support and minor cleanups for
brcmstb driver (Florian Fainelli and Markus Mayer).
- A new tegra driver and cleanup for the existing one (Sumit Gupta and
Jon Hunter).
- Bandwidth level support for Qcom driver along with OPP changes (Sibi
Sankar).
- Cleanups to sti, cpufreq-dt, ap806, CPPC drivers (Viresh Kumar, Lee
Jones, Ivan Kokshaysky, Sven Auhagen, and Xin Hao).
- Make schedutil default governor for ARM (Valentin Schneider).
- Fix dependency issues for imx (Walter Lozano).
- Cleanup around cached_resolved_idx in cpufreq core (Viresh Kumar)."
* 'cpufreq/arm/linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/vireshk/pm:
cpufreq: make schedutil the default for arm and arm64
cpufreq: cached_resolved_idx can not be negative
cpufreq: Add Tegra194 cpufreq driver
dt-bindings: arm: Add NVIDIA Tegra194 CPU Complex binding
cpufreq: imx: Select NVMEM_IMX_OCOTP
cpufreq: sti-cpufreq: Fix some formatting and misspelling issues
cpufreq: tegra186: Simplify probe return path
cpufreq: CPPC: Reuse caps variable in few routines
cpufreq: ap806: fix cpufreq driver needs ap cpu clk
cpufreq: cppc: Reorder code and remove apply_hisi_workaround variable
cpufreq: dt: fix oops on armada37xx
cpufreq: brcmstb-avs-cpufreq: send S2_ENTER / S2_EXIT commands to AVS
cpufreq: brcmstb-avs-cpufreq: Support polling AVS firmware
cpufreq: brcmstb-avs-cpufreq: more flexible interface for __issue_avs_command()
cpufreq: qcom: Disable fast switch when scaling DDR/L3
cpufreq: qcom: Update the bandwidth levels on frequency change
OPP: Add and export helper to set bandwidth
cpufreq: blacklist SC7180 in cpufreq-dt-platdev
cpufreq: blacklist SDM845 in cpufreq-dt-platdev
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It is not possible for cached_resolved_idx to be invalid here as the
cpufreq core always sets index to a positive value.
Change its type to unsigned int and fix qcom usage a bit.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
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Also provide missing function parameter description for 'cpu' and 'policy'.
Fixes the following W=1 kernel build warning(s):
drivers/cpufreq/cpufreq.c:60: warning: cannot understand function prototype: 'struct cpufreq_driver *cpufreq_driver; '
drivers/cpufreq/cpufreq.c:90: warning: Function parameter or member 'cpufreq_policy_notifier_list' not described in 'BLOCKING_NOTIFIER_HEAD'
drivers/cpufreq/cpufreq.c:312: warning: Function parameter or member 'val' not described in 'adjust_jiffies'
drivers/cpufreq/cpufreq.c:312: warning: Function parameter or member 'ci' not described in 'adjust_jiffies'
drivers/cpufreq/cpufreq.c:538: warning: Function parameter or member 'policy' not described in 'cpufreq_driver_resolve_freq'
drivers/cpufreq/cpufreq.c:686: warning: Function parameter or member 'file_name' not described in 'show_one'
drivers/cpufreq/cpufreq.c:686: warning: Function parameter or member 'object' not described in 'show_one'
drivers/cpufreq/cpufreq.c:731: warning: Function parameter or member 'file_name' not described in 'store_one'
drivers/cpufreq/cpufreq.c:731: warning: Function parameter or member 'object' not described in 'store_one'
drivers/cpufreq/cpufreq.c:741: warning: Function parameter or member 'policy' not described in 'show_cpuinfo_cur_freq'
drivers/cpufreq/cpufreq.c:741: warning: Function parameter or member 'buf' not described in 'show_cpuinfo_cur_freq'
drivers/cpufreq/cpufreq.c:754: warning: Function parameter or member 'policy' not described in 'show_scaling_governor'
drivers/cpufreq/cpufreq.c:754: warning: Function parameter or member 'buf' not described in 'show_scaling_governor'
drivers/cpufreq/cpufreq.c:770: warning: Function parameter or member 'policy' not described in 'store_scaling_governor'
drivers/cpufreq/cpufreq.c:770: warning: Function parameter or member 'buf' not described in 'store_scaling_governor'
drivers/cpufreq/cpufreq.c:770: warning: Function parameter or member 'count' not described in 'store_scaling_governor'
drivers/cpufreq/cpufreq.c:806: warning: Function parameter or member 'policy' not described in 'show_scaling_driver'
drivers/cpufreq/cpufreq.c:806: warning: Function parameter or member 'buf' not described in 'show_scaling_driver'
drivers/cpufreq/cpufreq.c:815: warning: Function parameter or member 'policy' not described in 'show_scaling_available_governors'
drivers/cpufreq/cpufreq.c:815: warning: Function parameter or member 'buf' not described in 'show_scaling_available_governors'
drivers/cpufreq/cpufreq.c:859: warning: Function parameter or member 'policy' not described in 'show_related_cpus'
drivers/cpufreq/cpufreq.c:859: warning: Function parameter or member 'buf' not described in 'show_related_cpus'
drivers/cpufreq/cpufreq.c:867: warning: Function parameter or member 'policy' not described in 'show_affected_cpus'
drivers/cpufreq/cpufreq.c:867: warning: Function parameter or member 'buf' not described in 'show_affected_cpus'
drivers/cpufreq/cpufreq.c:901: warning: Function parameter or member 'policy' not described in 'show_bios_limit'
drivers/cpufreq/cpufreq.c:901: warning: Function parameter or member 'buf' not described in 'show_bios_limit'
drivers/cpufreq/cpufreq.c:1625: warning: Function parameter or member 'dev' not described in 'cpufreq_remove_dev'
drivers/cpufreq/cpufreq.c:1625: warning: Function parameter or member 'sif' not described in 'cpufreq_remove_dev'
drivers/cpufreq/cpufreq.c:2380: warning: Function parameter or member 'cpu' not described in 'cpufreq_get_policy'
drivers/cpufreq/cpufreq.c:2771: warning: Function parameter or member 'driver' not described in 'cpufreq_unregister_driver'
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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The default cpufreq governor is chosen with the help of a "choice"
option in the Kconfig which will always end up selecting one of
the governors and so the weakly defined definition of
cpufreq_default_governor() will never get called.
Moreover, this makes us skip the checking of the return value of
that routine as it will always be non NULL.
If the Kconfig option changes in future, then we will start getting
a link error instead (and it won't go unnoticed as in the case of the
weak definition).
Suggested-by: Quentin Perret <qperret@google.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Currently, the only way to specify the default CPUfreq governor is
via Kconfig options, which suits users who can build the kernel
themselves perfectly.
However, for those who use a distro-like kernel (such as Android,
with the Generic Kernel Image project), the only way to use a
non-default governor is to boot to userspace, and to then switch
using the sysfs interface. Being able to specify the default governor
on the command line, like is the case for cpuidle, would allow those
users to specify their governor of choice earlier on, and to simplify
the userspace boot procedure slighlty.
To support this use-case, add a kernel command line parameter
allowing the default governor for CPUfreq to be specified, which
takes precedence over the built-in default.
This implementation has one notable limitation: the default governor
must be registered before the driver. This is solved for builtin
governors and drivers using appropriate *_initcall() functions. And
in the modular case, this must be reflected as a constraint on the
module loading order.
Signed-off-by: Quentin Perret <qperret@google.com>
[ Viresh: Converted 'default_governor' to a string and parsing it only
at initcall level, and several updates to
cpufreq_init_policy(). ]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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The locking around governors handling isn't adequate currently.
The list of governors should never be traversed without the locking
in place. Also governor modules must not be removed while the code
in them is still in use.
Reported-by: Quentin Perret <qperret@google.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: All applicable <stable@vger.kernel.org>
[ rjw: Changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Macro 'for_each_active_policy()' is defined internally. To avoid some
cpufreq driver needing this macro to iterate over all the policies in
'.set_boost' callback, we redefine '.set_boost' to act on only one
policy and pass the policy as an argument.
'cpufreq_boost_trigger_state()' iterates over all the policies to set
boost for the system.
This is preparation for adding SW BOOST support for CPPC.
To protect Boost enable/disable by sysfs from CPU online/offline,
add 'cpu_hotplug_lock' before calling '.set_boost' for each CPU.
Also move the lock from 'set_boost()' to 'store_cpb()' in
acpi_cpufreq.
Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Suggested-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Subject & changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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After commit 18c49926c4bf ("cpufreq: Add QoS requests for userspace
constraints") the return value of freq_qos_update_request(), that can
be 1, passed by cpufreq_boost_set_sw() to its caller sometimes
confuses the latter, which only expects to see 0 or negative error
codes, so notice that cpufreq_boost_set_sw() can return an error code
(which should not be -EINVAL for that matter) as soon as the first
policy without a frequency table is found (because either all policies
have a frequency table or none of them have it) and rework it to meet
its caller's expectations.
Fixes: 18c49926c4bf ("cpufreq: Add QoS requests for userspace constraints")
Reported-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reported-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: 5.3+ <stable@vger.kernel.org> # 5.3+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 updates from Catalin Marinas:
"The bulk is in-kernel pointer authentication, activity monitors and
lots of asm symbol annotations. I also queued the sys_mremap() patch
commenting the asymmetry in the address untagging.
Summary:
- In-kernel Pointer Authentication support (previously only offered
to user space).
- ARM Activity Monitors (AMU) extension support allowing better CPU
utilisation numbers for the scheduler (frequency invariance).
- Memory hot-remove support for arm64.
- Lots of asm annotations (SYM_*) in preparation for the in-kernel
Branch Target Identification (BTI) support.
- arm64 perf updates: ARMv8.5-PMU 64-bit counters, refactoring the
PMU init callbacks, support for new DT compatibles.
- IPv6 header checksum optimisation.
- Fixes: SDEI (software delegated exception interface) double-lock on
hibernate with shared events.
- Minor clean-ups and refactoring: cpu_ops accessor,
cpu_do_switch_mm() converted to C, cpufeature finalisation helper.
- sys_mremap() comment explaining the asymmetric address untagging
behaviour"
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (81 commits)
mm/mremap: Add comment explaining the untagging behaviour of mremap()
arm64: head: Convert install_el2_stub to SYM_INNER_LABEL
arm64: Introduce get_cpu_ops() helper function
arm64: Rename cpu_read_ops() to init_cpu_ops()
arm64: Declare ACPI parking protocol CPU operation if needed
arm64: move kimage_vaddr to .rodata
arm64: use mov_q instead of literal ldr
arm64: Kconfig: verify binutils support for ARM64_PTR_AUTH
lkdtm: arm64: test kernel pointer authentication
arm64: compile the kernel with ptrauth return address signing
kconfig: Add support for 'as-option'
arm64: suspend: restore the kernel ptrauth keys
arm64: __show_regs: strip PAC from lr in printk
arm64: unwind: strip PAC from kernel addresses
arm64: mask PAC bits of __builtin_return_address
arm64: initialize ptrauth keys for kernel booting task
arm64: initialize and switch ptrauth kernel keys
arm64: enable ptrauth earlier
arm64: cpufeature: handle conflicts based on capability
arm64: cpufeature: Move cpu capability helpers inside C file
...
|
|
Add weak function to return the hardware maximum frequency of a CPU,
with the default implementation returning cpuinfo.max_freq, which is
the best information we can generically get from the cpufreq framework.
The default can be overwritten by a strong function in platforms
that want to provide an alternative implementation, with more accurate
information, obtained either from hardware or firmware.
Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
|
|
Before commit 1e4f63aecb53 ("cpufreq: Avoid creating excessively
large stack frames") the initial value of the policy field in struct
cpufreq_policy set by the driver's ->init() callback was implicitly
passed from cpufreq_init_policy() to cpufreq_set_policy() if the
default governor was neither "performance" nor "powersave". After
that commit, however, cpufreq_init_policy() must take that case into
consideration explicitly and handle it as appropriate, so make that
happen.
Fixes: 1e4f63aecb53 ("cpufreq: Avoid creating excessively large stack frames")
Link: https://lore.kernel.org/linux-pm/39fb762880c27da110086741315ca8b111d781cd.camel@gmail.com/
Reported-by: Artem Bityutskiy <dedekind1@gmail.com>
Cc: 5.4+ <stable@vger.kernel.org> # 5.4+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
|
|
The cpufreq_global_kobject is only used internally by cpufreq.c
after commit 2361be236662 ("cpufreq: Don't create empty
/sys/devices/system/cpu/cpufreq directory").
Make it static.
Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
[ rjw: Add empty line after cpufreq_global_kobject definition ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
|
|
In the process of modifying a cpufreq policy, the cpufreq core makes
a copy of it including all of the internals which is stored on the
CPU stack. Because struct cpufreq_policy is relatively large, this
may cause the size of the stack frame to exceed the 2 KB limit and
so the GCC complains when -Wframe-larger-than= is used.
In fact, it is not necessary to copy the entire policy structure
in order to modify it, however.
First, because cpufreq_set_policy() obtains the min and max policy
limits from frequency QoS now, it is not necessary to pass the limits
to it from the callers. The only things that need to be passed to it
from there are the new governor pointer or (if there is a built-in
governor in the driver) the "policy" value representing the governor
choice. They both can be passed as individual arguments, though, so
make cpufreq_set_policy() take them this way and rework its callers
accordingly. This avoids making copies of cpufreq policies in the
callers of cpufreq_set_policy().
Second, cpufreq_set_policy() still needs to pass the new policy
data to the ->verify() callback of the cpufreq driver whose task
is to sanitize the min and max policy limits. It still does not
need to make a full copy of struct cpufreq_policy for this purpose,
but it needs to pass a few items from it to the driver in case they
are needed (different drivers have different needs in that respect
and all of them have to be covered). For this reason, introduce
struct cpufreq_policy_data to hold copies of the members of
struct cpufreq_policy used by the existing ->verify() driver
callbacks and pass a pointer to a temporary structure of that
type to ->verify() (instead of passing a pointer to full struct
cpufreq_policy to it).
While at it, notice that intel_pstate and longrun don't really need
to verify the "policy" value in struct cpufreq_policy, so drop those
check from them to avoid copying "policy" into struct
cpufreq_policy_data (which allows it to be slightly smaller).
Also while at it fix up white space in a couple of places and make
cpufreq_set_policy() static (as it can be so).
Fixes: 3000ce3c52f8 ("cpufreq: Use per-policy frequency QoS")
Link: https://lore.kernel.org/linux-pm/CAMuHMdX6-jb1W8uC2_237m8ctCpsnGp=JCxqt8pCWVqNXHmkVg@mail.gmail.com
Reported-by: kbuild test robot <lkp@intel.com>
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: 5.4+ <stable@vger.kernel.org> # 5.4+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
|
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git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management updates from Rafael Wysocki:
"These include cpuidle changes to use nanoseconds (instead of
microseconds) as the unit of time and to simplify checks for disabled
idle states in the idle loop, some cpuidle fixes and governor updates,
assorted cpufreq updates (driver updates mostly and a few core fixes
and cleanups), devfreq updates (dominated by the tegra30 driver
changes), new CPU IDs for the RAPL power capping driver, relatively
minor updates of the generic power domains (genpd) and operation
performance points (OPP) frameworks, and assorted fixes and cleanups.
There are also two maintainer information updates: Chanwoo Choi will
be maintaining the devfreq subsystem going forward and Todd Brandt is
going to maintain the pm-graph utility (created by him).
Specifics:
- Use nanoseconds (instead of microseconds) as the unit of time in
the cpuidle core and simplify checks for disabled idle states in
the idle loop (Rafael Wysocki)
- Fix and clean up the teo cpuidle governor (Rafael Wysocki)
- Fix the cpuidle registration error code path (Zhenzhong Duan)
- Avoid excessive vmexits in the ACPI cpuidle driver (Yin Fengwei)
- Extend the idle injection infrastructure to be able to measure the
requested duration in nanoseconds and to allow an exit latency
limit for idle states to be specified (Daniel Lezcano)
- Fix cpufreq driver registration and clarify a comment in the
cpufreq core (Viresh Kumar)
- Add NULL checks to the show() and store() methods of sysfs
attributes exposed by cpufreq (Kai Shen)
- Update cpufreq drivers:
* Fix for a plain int as pointer warning from sparse in
intel_pstate (Jamal Shareef)
* Fix for a hardcoded number of CPUs and stack bloat in the
powernv driver (John Hubbard)
* Updates to the ti-cpufreq driver and DT files to support new
platforms and migrate bindings from opp-v1 to opp-v2 (Adam Ford,
H. Nikolaus Schaller)
* Merging of the arm_big_little and vexpress-spc drivers and
related cleanup (Sudeep Holla)
* Fix for imx's default speed grade value (Anson Huang)
* Minor cleanup of the s3c64xx driver (Nathan Chancellor)
* CPU speed bin detection fix for sun50i (Ondrej Jirman)
- Appoint Chanwoo Choi as the new devfreq maintainer.
- Update the devfreq core:
* Check NULL governor in available_governors_show sysfs to prevent
showing wrong governor information and fix a race condition
between devfreq_update_status() and trans_stat_show() (Leonard
Crestez)
* Add new 'interrupt-driven' flag for devfreq governors to allow
interrupt-driven governors to prevent the devfreq core from
polling devices for status (Dmitry Osipenko)
* Improve an error message in devfreq_add_device() (Matthias
Kaehlcke)
- Update devfreq drivers:
* tegra30 driver fixes and cleanups (Dmitry Osipenko)
* Removal of unused property from dt-binding documentation for the
exynos-bus driver (Kamil Konieczny)
* exynos-ppmu cleanup and DT bindings update (Lukasz Luba, Marek
Szyprowski)
- Add new CPU IDs for CometLake Mobile and Desktop to the Intel RAPL
power capping driver (Zhang Rui)
- Allow device initialization in the generic power domains (genpd)
framework to be more straightforward and clean it up (Ulf Hansson)
- Add support for adjusting OPP voltages at run time to the OPP
framework (Stephen Boyd)
- Avoid freeing memory that has never been allocated in the
hibernation core (Andy Whitcroft)
- Clean up function headers in a header file and coding style in the
wakeup IRQs handling code (Ulf Hansson, Xiaofei Tan)
- Clean up the SmartReflex adaptive voltage scaling (AVS) driver for
ARM (Ben Dooks, Geert Uytterhoeven)
- Wrap power management documentation to fit in 80 columns (Bjorn
Helgaas)
- Add pm-graph utility entry to MAINTAINERS (Todd Brandt)
- Update the cpupower utility:
* Fix the handling of set and info subcommands (Abhishek Goel)
* Fix build warnings (Nathan Chancellor)
* Improve mperf_monitor handling (Janakarajan Natarajan)"
* tag 'pm-5.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (83 commits)
PM: Wrap documentation to fit in 80 columns
cpuidle: Pass exit latency limit to cpuidle_use_deepest_state()
cpuidle: Allow idle injection to apply exit latency limit
cpuidle: Introduce cpuidle_driver_state_disabled() for driver quirks
cpuidle: teo: Avoid code duplication in conditionals
cpufreq: Register drivers only after CPU devices have been registered
cpuidle: teo: Avoid using "early hits" incorrectly
cpuidle: teo: Exclude cpuidle overhead from computations
PM / Domains: Convert to dev_to_genpd_safe() in genpd_syscore_switch()
mmc: tmio: Avoid boilerplate code in ->runtime_suspend()
PM / Domains: Implement the ->start() callback for genpd
PM / Domains: Introduce dev_pm_domain_start()
ARM: OMAP2+: SmartReflex: add omap_sr_pdata definition
PM / wakeirq: remove unnecessary parentheses
power: avs: smartreflex: Remove superfluous cast in debugfs_create_file() call
cpuidle: Use nanoseconds as the unit of time
PM / OPP: Support adjusting OPP voltages at runtime
PM / core: Clean up some function headers in power.h
cpufreq: Add NULL checks to show() and store() methods of cpufreq
cpufreq: intel_pstate: Fix plain int as pointer warning from sparse
...
|
|
We can now safely read user and guest kcpustat fields on nohz_full CPUs.
Use the appropriate accessors.
Reported-by: Yauheni Kaliuta <yauheni.kaliuta@redhat.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wanpeng Li <wanpengli@tencent.com>
Link: https://lkml.kernel.org/r/20191121024430.19938-5-frederic@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
The cpufreq core heavily depends on the availability of the struct
device for CPUs and if they aren't available at the time cpufreq driver
is registered, we will never succeed in making cpufreq work.
This happens due to following sequence of events:
- cpufreq_register_driver()
- subsys_interface_register()
- return 0; //successful registration of driver
... at a later point of time
- register_cpu();
- device_register();
- bus_probe_device();
- sif->add_dev();
- cpufreq_add_dev();
- get_cpu_device(); //FAILS
- per_cpu(cpu_sys_devices, num) = &cpu->dev; //used by get_cpu_device()
- return 0; //CPU registered successfully
Because the per-cpu variable cpu_sys_devices is set only after the CPU
device is regsitered, cpufreq will never be able to get it when
cpufreq_add_dev() is called.
This patch avoids this failure by making sure device structure of at
least CPU0 is available when the cpufreq driver is registered, else
return -EPROBE_DEFER.
Reported-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Co-developed-by: Amit Kucheria <amit.kucheria@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Amit Kucheria <amit.kucheria@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
|
