This driver is the only one that calls regulator_sync_voltage(), but it
can currently be built with CONFIG_REGULATOR disabled, producing
this build error:
drivers/cpufreq/tegra124-cpufreq.c: In function 'tegra124_cpu_switch_to_pllx':
drivers/cpufreq/tegra124-cpufreq.c:68:2: error: implicit declaration of function 'regulator_sync_voltage' [-Werror=implicit-function-declaration]
regulator_sync_voltage(priv->vdd_cpu_reg);
My first attempt was to implement a helper for this function
for regulator_sync_voltage, but Mark Brown explained:
We don't do this for *all* regulator API functions - there's some where
using them strongly suggests that there is actually a dependency on
the regulator API. This does seem like it might be falling into the
specialist category [...]
Looking at the code I'm pretty unclear on what the authors think the
use of _sync_voltage() is doing in the first place so it may be even
better to just remove the call. It seems to have been included in the
first commit so there's not changelog explaining things and there's
no comment either. I'd *expect* it to be a noop as far as I can see.
This adds the dependency to make the driver always build successfully
or not be enabled at all. Alternatively, we could investigate if the
driver should stop calling regulator_sync_voltage instead.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Merge "Fixes for Exynos" from Krzysztof Kozlowski:
1. Fix potential NULL pointer dereference in Exynos PMU driver.
2. Remove incorrect __init annotation from s3c24xx cpufreq driver
structures.
* tag 'samsung-fixes-4.4' of https://git.kernel.org/pub/scm/linux/kernel/git/krzk/linux:
cpufreq: s3c24xx: Do not mark s3c2410_plls_add as __init
ARM: EXYNOS: Fix potential NULL pointer access in exynos_sys_powerdown_conf
In cases where we have many IOs, the global load becomes low and the
load algorithm will decrease the requested P-State. Because of that,
the IOs overheads will increase and impact the IO performances.
To improve IO bound work, we can count the io-wait time as busy time
in calculating CPU busy.
This change uses get_cpu_iowait_time_us() to obtain the IO wait time value
and converts time into number of cycles spent waiting on IO at the TSC
rate. At the moment, this trick is only used for Atom.
Signed-off-by: Philippe Longepe <philippe.longepe@intel.com>
Signed-off-by: Stephane Gasparini <stephane.gasparini@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The current function to calculate cpu utilization uses the average P-state
ratio (APerf/Mperf) scaled by the ratio of the current P-state to the
max available non-turbo one. This leads to an overestimation of
utilization which causes higher-performance P-states to be selected more
often and that leads to increased energy consumption.
This is a problem for low-power systems, so it is better to use a
different utilization calculation algorithm for them.
Namely, the Percent Busy value (or load) can be estimated as the ratio of the
MPERF counter that runs at a constant rate only during active periods (C0) to
the time stamp counter (TSC) that also runs (at the same rate) during idle.
That is:
Percent Busy = 100 * (delta_mperf / delta_tsc)
Use this algorithm for platforms with SoCs based on the Airmont and Silvermont
Atom cores.
Signed-off-by: Philippe Longepe <philippe.longepe@intel.com>
Signed-off-by: Stephane Gasparini <stephane.gasparini@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Target systems using different cpus have different power and performance
requirements. They may use different algorithms to get the next P-state
based on their power or performance preference.
For example, power-constrained systems may not want to use
high-performance P-states as aggressively as a full-size desktop or a
server platform. A server platform may want to run close to the max to
achieve better performance, while laptop-like systems may prefer
sacrificing performance for longer battery lifes.
For the above reasons, modify intel_pstate to allow the target P-state
selection algorithm to be depend on the CPU ID.
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Philippe Longepe <philippe.longepe@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Sometimes regulator_get_voltage() call returns negative values for
reasons(e.g. underlying I2C bus timeout). Add check for the return
values and fail out early.
Signed-off-by: Pi-Cheng Chen <pi-cheng.chen@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Remove redundant regulator_get_voltage() call to get Vsram value
since it will be obtained later at the beginning of voltage tracking
loop.
Signed-off-by: Pi-Cheng Chen <pi-cheng.chen@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Register the qoriq cpufreq driver as a cooling device, based on the
thermal device tree framework. When temperature crosses the passive trip
point cpufreq is used to throttle CPUs.
Signed-off-by: Jia Hongtao <hongtao.jia@freescale.com>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The cpufreq documentation specifies
policy->cpuinfo.transition_latency the time it takes on this CPU to
switch between two frequencies in
nanoseconds (if appropriate, else
specify CPUFREQ_ETERNAL)
currently pcc-cpufreq does not expose the value and sets it to zero. I
changed the pcc-cpufreq driver and it's documentation to conform to the
default value specified in Documentation/cpu-freq/cpu-drivers.txt
Signed-off-by: Jacob Tanenbaum <jtanenba@redhat.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Register passive cooling devices when initialising cpufreq on
big.LITTLE systems. If the device tree provides a dynamic power
coefficient for the CPUs then the bound cooling device will support
the extensions that allow it to be used with all the existing thermal
governors including the power allocator governor.
A cooling device will be created per individual frequency domain and
can be bound to thermal zones via the thermal DT bindings.
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Support registering cooling devices with dynamic power coefficient
where provided by the device tree. This allows OF registered cooling
devices driver to be used with the power_allocator thermal governor.
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Javi Merino <javi.merino@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
It is possible to get rid of the timer_lock spinlock used by the
governor timer function for synchronization, but a couple of races
need to be avoided.
The first race is between multiple dbs_timer_handler() instances
that may be running in parallel with each other on different
CPUs. Namely, one of them has to queue up the work item, but it
cannot be queued up more than once. To achieve that,
atomic_inc_return() can be used on the skip_work field of
struct cpu_common_dbs_info.
The second race is between an already running dbs_timer_handler()
and gov_cancel_work(). In that case the dbs_timer_handler() might
not notice the skip_work incrementation in gov_cancel_work() and
it might queue up its work item after gov_cancel_work() had
returned (and that work item would corrupt skip_work going
forward). To prevent that from happening, gov_cancel_work()
can be made wait for the timer function to complete (on all CPUs)
right after skip_work has been incremented.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Currently update_sampling_rate() runs over each online CPU and
cancels/queues timers on all policy->cpus every time. This should be
done just once for any cpu belonging to a policy.
Create a cpumask and keep on clearing it as and when we process
policies, so that we don't have to traverse through all CPUs of the same
policy.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
cpufreq governors evaluate load at sampling rate and based on that they
update frequency for a group of CPUs belonging to the same cpufreq
policy.
This is required to be done in a single thread for all policy->cpus, but
because we don't want to wakeup idle CPUs to do just that, we use
deferrable work for this. If we would have used a single delayed
deferrable work for the entire policy, there were chances that the CPU
required to run the handler can be in idle and we might end up not
changing the frequency for the entire group with load variations.
And so we were forced to keep per-cpu works, and only the one that
expires first need to do the real work and others are rescheduled for
next sampling time.
We have been using the more complex solution until now, where we used a
delayed deferrable work for this, which is a combination of a timer and
a work.
This could be made lightweight by keeping per-cpu deferred timers with a
single work item, which is scheduled by the first timer that expires.
This patch does just that and here are important changes:
- The timer handler will run in irq context and so we need to use a
spin_lock instead of the timer_mutex. And so a separate timer_lock is
created. This also makes the use of the mutex and lock quite clear, as
we know what exactly they are protecting.
- A new field 'skip_work' is added to track when the timer handlers can
queue a work. More comments present in code.
Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Ashwin Chaugule <ashwin.chaugule@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
timer_mutex is required to be initialized only while memory for 'shared'
is allocated and in a similar way it is required to be destroyed only
when memory for 'shared' is freed.
There is no need to do the same every time we start/stop the governor.
Move code to initialize/destroy timer_mutex to the relevant places.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
We are guaranteed to have works scheduled for policy->cpus, as the
policy isn't stopped yet. And so there is no need to check that again.
Drop it.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
We are comparing policy->governor against cpufreq_gov_ondemand to make
sure that we update sampling rate only for the concerned CPUs. But that
isn't enough.
In case of governor_per_policy, there can be multiple instances of
ondemand governor and we will always end up updating all of them with
current code. What we rather need to do, is to compare dbs_data with
poilcy->governor_data, which will match only for the policies governed
by dbs_data.
This code is also racy as the governor might be getting stopped at that
time and we may end up scheduling work for a policy, which we have just
disabled.
Fix that by protecting the entire function with &od_dbs_cdata.mutex,
which will prevent against races with policy START/STOP/etc.
After these locks are in place, we can safely get the policy via per-cpu
dbs_info.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* pm-domains:
PM / Domains: Fix bad of_node_put() in failure paths of genpd_dev_pm_attach()
PM / Domains: Validate cases of a non-bound driver in genpd governor
* pm-cpufreq:
cpufreq: use last policy after online for drivers with ->setpolicy
For cpufreq drivers which use setpolicy interface, after offline->online
the policy is set to default. This can be reproduced by setting the
default policy of intel_pstate or longrun to ondemand and then change to
"performance". After offline and online, the setpolicy will be called with
the policy=ondemand.
For drivers using governors this condition is handled by storing
last_governor, during offline and restoring during online. The same should
be done for drivers using setpolicy interface. Storing last_policy during
offline and restoring during online.
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
s3c2410_plls_add is a device notifier that may be called at runtime and
is correctly not marked __init. However it calls s3c_plltab_register()
which is marked __init, and that triggers a build error when we are
checking for section mismatches:
WARNING: vmlinux.o(.text+0x195e0): Section mismatch in reference from the function s3c2410_plls_add() to the function .init.text:s3c_plltab_register()
The function s3c2410_plls_add() references
the function __init s3c_plltab_register().
This is often because s3c2410_plls_add lacks a __init
annotation or the annotation of s3c_plltab_register is wrong.
This removes the __init annotation from s3c2410_plls_add as well as the
__initdata section annotations from s3c2440_plls_12 and s3c2440_plls_169344,
which in turn are referenced from s3c2410_plls_add.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
If hardware-driven P-state selection (HWP) is enabled, the
"performance" mode of intel_pstate should only allow the processor
to use the highest-performance P-state available. That is not
the case currently, so make it actually happen.
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Alexandra Yates <alexandra.yates@linux.intel.com>
[ rjw: Subject and changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The SCPI clk driver registers the virtual cpufreq device that kicks off
initialisation of the SCPI cpufreq driver. Also, clk_get() will fail for
the cpufreq driver if the SCPI clk driver is missing.
Fix this by making the SCPI cpufreq driver explicitly depend on the SCPI
clk driver.
Fixes: 8def31034d (cpufreq: arm_big_little: add SCPI interface driver)
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Arnd Bergmann
Philippe Longepe
Pi-Cheng Chen
Hongtao Jia
Jacob Tanenbaum
Punit Agrawal
Rafael J. Wysocki
Viresh Kumar
Srinivas Pandruvada
Alexandra Yates