cpufreq: scmi: Enable boost support

Certain platforms host a number of higher OPPs that are exclusive to
CPUs within specific CPUfreq policies and not all CPUs within that
CPUfreq policy are able to achieve those higher OPPs due to power
constraints. These OPPs are marked as turbo in the freq_table and in
the presence of such OPPs, let's enable boost by default.

Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Sibi Sankar <quic_sibis@quicinc.com>
Reviewed-by: Dhruva Gole <d-gole@ti.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

cpufreq: scmi: Set transition_delay_us

Make use of the newly added callbacks:
- rate_limit_get()
- fast_switch_rate_limit()
to populate policies's `transition_delay_us`, defined as the
'Preferred average time interval between consecutive
invocations of the driver to set the frequency for this policy.'

Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

cpufreq: scmi: process the result of devm_of_clk_add_hw_provider()

devm_of_clk_add_hw_provider() may return an errno, so
add a return value check

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 8410e7f3b31e ("cpufreq: scmi: Fix OPP addition failure with a dummy clock provider")
Signed-off-by: Alexandra Diupina <adiupina@astralinux.ru>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

cpufreq: scmi: Add support to parse domain-id using #power-domain-cells

The performance domain-id can be described in DT using the power-domains
property or the clock property. The latter is already supported, so let's
add support for the power-domains too.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Link: https://lore.kernel.org/r/20230825112633.236607-12-ulf.hansson@linaro.org
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

cpufreq: scmi: Avoid one OF parsing in scmi_get_sharing_cpus()

The domain-id for the cpu_dev has already been parsed at the point when
scmi_get_sharing_cpus() is getting called. Let's pass it as an in-parameter
to avoid the unnecessary OF parsing.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Link: https://lore.kernel.org/r/20230825112633.236607-7-ulf.hansson@linaro.org
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Align perf ops to use domain-id as in-parameter

Most scmi_perf_proto_ops are already using an "u32 domain" as an
in-parameter to indicate what performance domain we shall operate upon.
However, some of the ops are using a "struct device *dev", which means that
an additional OF parsing is needed each time the perf ops gets called, to
find the corresponding domain-id.

To avoid the above, but also to make the code more consistent, let's
replace the in-parameter "struct device *dev" with an "u32 domain". Note
that, this requires us to make some corresponding changes to the scmi
cpufreq driver, so let's do that too.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Link: https://lore.kernel.org/r/20230825112633.236607-5-ulf.hansson@linaro.org
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

cpufreq: scmi: Prepare to move OF parsing of domain-id to cpufreq

The OF parsing of the clock domain specifier seems to better belong in the
scmi cpufreq driver, rather than being implemented behind the generic
->device_domain_id() perf protocol ops.

To prepare to remove the ->device_domain_id() ops, let's implement the OF
parsing in the scmi cpufreq driver instead.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Link: https://lore.kernel.org/r/20230825112633.236607-4-ulf.hansson@linaro.org
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

cpufreq: Use of_property_present() for testing DT property presence

It is preferred to use typed property access functions (i.e.
of_property_read_<type> functions) rather than low-level
of_get_property/of_find_property functions for reading properties. As
part of this, convert of_get_property/of_find_property calls to the
recently added of_property_present() helper when we just want to test
for presence of a property and nothing more.

Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

cpufreq: scmi: Support the power scale in micro-Watts in SCMI v3.1

The SCMI v3.1 adds support for power values in micro-Watts. They are not
always in milli-Watts anymore (ignoring the bogo-Watts). Thus, the power
must be converted conditionally before sending to Energy Model. Add the
logic which handles the needed checks and conversions.

Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM: EM: convert power field to micro-Watts precision and align drivers

The milli-Watts precision causes rounding errors while calculating
efficiency cost for each OPP. This is especially visible in the 'simple'
Energy Model (EM), where the power for each OPP is provided from OPP
framework. This can cause some OPPs to be marked inefficient, while
using micro-Watts precision that might not happen.

Update all EM users which access 'power' field and assume the value is
in milli-Watts.

Solve also an issue with potential overflow in calculation of energy
estimation on 32bit machine. It's needed now since the power value
(thus the 'cost' as well) are higher.

Example calculation which shows the rounding error and impact:

power = 'dyn-power-coeff' * volt_mV * volt_mV * freq_MHz

power_a_uW = (100 * 600mW * 600mW * 500MHz) / 10^6 = 18000
power_a_mW = (100 * 600mW * 600mW * 500MHz) / 10^9 = 18

power_b_uW = (100 * 605mW * 605mW * 600MHz) / 10^6 = 21961
power_b_mW = (100 * 605mW * 605mW * 600MHz) / 10^9 = 21

max_freq = 2000MHz

cost_a_mW = 18 * 2000MHz/500MHz = 72
cost_a_uW = 18000 * 2000MHz/500MHz = 72000

cost_b_mW = 21 * 2000MHz/600MHz = 70 // <- artificially better
cost_b_uW = 21961 * 2000MHz/600MHz = 73203

The 'cost_b_mW' (which is based on old milli-Watts) is misleadingly
better that the 'cost_b_uW' (this patch uses micro-Watts) and such
would have impact on the 'inefficient OPPs' information in the Cpufreq
framework. This patch set removes the rounding issue.

Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM: EM: Change the order of arguments in the .active_power() callback

The .active_power() callback passes the device pointer when it's called.
Aligned with a convetion present in other subsystems and pass the 'dev'
as a first argument. It looks more cleaner.

Adjust all affected drivers which implement that API callback.

Suggested-by: Ionela Voinescu <ionela.voinescu@arm.com>
Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
Reviewed-by: Ionela Voinescu <ionela.voinescu@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: replace cpumask_weight with cpumask_empty where appropriate

drivers/cpufreq calls cpumask_weight() to check if any bit of a given
cpumask is set. We can do it more efficiently with cpumask_empty() because
cpumask_empty() stops traversing the cpumask as soon as it finds first set
bit, while cpumask_weight() counts all bits unconditionally.

Signed-off-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com> (for SCMI cpufreq driver)
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

cpufreq: scmi: Use .register_em() to register with energy model

Set the newly added .register_em() callback to register with the EM
after the cpufreq policy is properly initialized.

Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

cpufreq: arm_scmi: Fix error path when allocation failed

Stop the initialization when cpumask allocation failed and return an
error.

Fixes: 80a064dbd556 ("scmi-cpufreq: Get opp_shared_cpus from opp-v2 for EM")
Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

cpufreq: scmi: Fix an error message

'ret' is known to be 0 here.
The last error code is stored in 'nr_opp', so use it in the error message.

Fixes: 71a37cd6a59d ("scmi-cpufreq: Remove deferred probe")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

cpufreq: scmi: Port driver to the new scmi_perf_proto_ops interface

Port driver to the new SCMI perf interface based on protocol handles
and common devm_get_ops().

Link: https://lore.kernel.org/r/20210316124903.35011-13-cristian.marussi@arm.com
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

scmi-cpufreq: Get opp_shared_cpus from opp-v2 for EM

By design, SCMI performance domains define the granularity of
performance controls, they do not describe any underlying hardware
dependencies (although they may match in many cases).

It is therefore possible to have some platforms where hardware may have
the ability to control CPU performance at different granularity and choose
to describe fine-grained performance control through SCMI.

In such situations, the energy model would be provided with inaccurate
information based on controls, while it still needs to know the
performance boundaries.

To restore correct functionality, retrieve information of CPUs under the
same performance domain from operating-points-v2 in DT, and pass it on to
EM.

Link: https://lore.kernel.org/r/20210218222326.15788-3-nicola.mazzucato@arm.com
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Nicola Mazzucato <nicola.mazzucato@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

scmi-cpufreq: Remove deferred probe

The current implementation of the scmi_cpufreq_init() function returns
-EPROBE_DEFER when the OPP table is not populated. In practice the
cpufreq core cannot handle this error code.
Therefore, fix the return value and clarify the error message.

Link: https://lore.kernel.org/r/20210218222326.15788-2-nicola.mazzucato@arm.com
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Nicola Mazzucato <nicola.mazzucato@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

cpufreq: Remove CPUFREQ_STICKY flag

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>

cpufreq: arm_scmi: Discover the power scale in performance protocol

Add mechanism to discover the power scale present in the performance
protocol for all domains. Provide this information to Energy Model,
which then can be checked in other frameworks, e.g. thermal.

Suggested-by: Morten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

cpufreq: scmi: Fix build for !CONFIG_COMMON_CLK

Commit 8410e7f3b31e ("cpufreq: scmi: Fix OPP addition failure with a
dummy clock provider") registers a dummy clock provider using
devm_of_clk_add_hw_provider. These *_hw_provider functions are defined
only when CONFIG_COMMON_CLK=y. One possible fix is to add the Kconfig
dependency, but since we plan to move away from the clock dependency
for scmi cpufreq, it is preferrable to avoid that.

Let us just conditionally compile out the offending call to
devm_of_clk_add_hw_provider. It also uses the variable 'dev' outside
of the #ifdef block to avoid build warning.

Fixes: 8410e7f3b31e ("cpufreq: scmi: Fix OPP addition failure with a dummy clock provider")
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

cpufreq: scmi: Fix OPP addition failure with a dummy clock provider

Commit dd461cd9183f ("opp: Allow dev_pm_opp_get_opp_table() to return
-EPROBE_DEFER") handles -EPROBE_DEFER for the clock/interconnects within
_allocate_opp_table() which is called from dev_pm_opp_add and it
now propagates the error back to the caller.

SCMI performance domain re-used clock bindings to keep it simple. However
with the above mentioned change, if clock property is present in a device
node, opps fails to get added with below errors until clk_get succeeds.

cpu0: failed to add opp 450000000Hz
cpu0: failed to add opps to the device
....(errors on cpu1-cpu4)
cpu5: failed to add opp 450000000Hz
cpu5: failed to add opps to the device

So, in order to fix the issue, we need to register dummy clock provider.
With the dummy clock provider, clk_get returns NULL(no errors!), then opp
core proceeds to add OPPs for the CPUs.

Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Fixes: dd461cd9183f ("opp: Allow dev_pm_opp_get_opp_table() to return -EPROBE_DEFER")
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

PM: EM: Add a flag indicating units of power values in Energy Model

There are different platforms and devices which might use different scale
for the power values. Kernel sub-systems might need to check if all
Energy Model (EM) devices are using the same scale. Address that issue and
store the information inside EM for each device. Thanks to that they can
be easily compared and proper action triggered.

Suggested-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Quentin Perret <qperret@google.com>
Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: move invariance setter calls in cpufreq core

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>

cpufreq: arm_scmi: Constify scmi_perf_ops pointers

The perf_ops are not modified through this pointer. Make them const to
indicate that. This is in preparation to make the scmi-ops pointers in
scmi_handle const.

Link: https://lore.kernel.org/r/20200906230452.33410-2-rikard.falkeborn@gmail.com
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

cpufreq: arm_scmi: Set fast_switch_possible conditionally

Currently the fast_switch_possible flag is set unconditionally to true.
Based on this, schedutil does not create a thread for frequency
switching and would always use the fast switch path.

However, if the platform does not support SCMI fast channel, we use
polling mode for SCMI message transfer. This may be possible only if
there is dedicated channel for DVFS and all operations are in polling
mode.

Update this by retrieving the fast_switch capability based on the
presence of fast channels in SCMI platform firmware.

Link: https://lore.kernel.org/r/20200617094332.8391-2-nicola.mazzucato@arm.com
Suggested-by: Lukasz Luba <lukasz.luba@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Nicola Mazzucato <nicola.mazzucato@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

PM / EM: update callback structure and add device pointer

The Energy Model framework is going to support devices other that CPUs. In
order to make this happen change the callback function and add pointer to
a device as an argument.

Update the related users to use new function and new callback from the
Energy Model.

Acked-by: Quentin Perret <qperret@google.com>
Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: scmi: Match scmi device by both name and protocol id

The scmi bus now has support to match the driver with devices not only
based on their protocol id but also based on their device name if one is
available. This was added to cater the need to support multiple devices
and drivers for the same protocol.

Let us add the name "cpufreq" to scmi_device_id table in the driver so
that in matches only with device with the same name and protocol id
SCMI_PROTOCOL_PERF. This will help to add "devfreq" device/driver.

Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

cpufreq: scmi: Fix use-after-free in scmi_cpufreq_exit()

This issue was detected with the help of Coccinelle. So
change the order of function calls to fix it.

Fixes: 1690d8bb91e37 (cpufreq: scpi/scmi: Fix freeing of dynamic OPPs)

Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Cc: 4.20+ <stable@vger.kernel.org> # 4.20+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: scmi: Register an Energy Model

The Energy Model (EM) framework provides an API to register the active
power of CPUs. Call this API from the scmi-cpufreq driver by using the
power costs obtained from firmware. This is done to ensure interested
subsystems (the task scheduler, for example) can make use of the EM
when available.

Signed-off-by: Quentin Perret <quentin.perret@arm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

cpufreq: scmi: Use auto-registration of thermal cooling device

Use the CPUFREQ_IS_COOLING_DEV flag to allow cpufreq core to
automatically register as a thermal cooling device.

This allows removal of boiler plate code from the driver.

Signed-off-by: Amit Kucheria <amit.kucheria@linaro.org>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: scmi: Fix frequency invariance in slow path

The scmi-cpufreq driver calls the arch_set_freq_scale() callback on
frequency changes to provide scale-invariant load-tracking signals to
the scheduler. However, in the slow path, it does so while specifying
the current and max frequencies in different units, hence resulting in a
broken freq_scale factor.

Fix this by passing all frequencies in KHz, as stored in the CPUFreq
frequency table.

Fixes: 99d6bdf33877 (cpufreq: add support for CPU DVFS based on SCMI message protocol)
Signed-off-by: Quentin Perret <quentin.perret@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Cc: 4.17+ <stable@vger.kernel.org> # v4.17+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: scpi/scmi: Fix freeing of dynamic OPPs

Since the commit 2a4eb7358aba "OPP: Don't remove dynamic OPPs from
_dev_pm_opp_remove_table()", dynamically created OPP aren't
automatically removed anymore by dev_pm_opp_cpumask_remove_table(). This
affects the scpi and scmi cpufreq drivers which no longer free OPPs on
failures or on invocations of the policy->exit() callback.

Create a generic OPP helper dev_pm_opp_remove_all_dynamic() which can be
called from these drivers instead of dev_pm_opp_cpumask_remove_table().

In dev_pm_opp_remove_all_dynamic(), we need to make sure that the
opp_list isn't getting accessed simultaneously from other parts of the
OPP core while the helper is freeing dynamic OPPs, i.e. we can't drop
the opp_table->lock while traversing through the OPP list. And to
accomplish that, this patch also creates _opp_kref_release_unlocked()
which can be called from this new helper with the opp_table lock already
held.

Cc: 4.20 <stable@vger.kernel.org> # v4.20
Reported-by: Valentin Schneider <valentin.schneider@arm.com>
Fixes: 2a4eb7358aba "OPP: Don't remove dynamic OPPs from _dev_pm_opp_remove_table()"
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Valentin Schneider <valentin.schneider@arm.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

firmware: arm_scmi: rename get_transition_latency and add_opps_to_device

Most of the scmi code follows the suggestion from Greg KH on a totally
different thread[0] to have the subsystem name first, followed by the
noun and finally the verb with couple of these exceptions.

This patch fixes them so that all the functions names are aligned to
that practice.

[0] https://www.spinics.net/lists/arm-kernel/msg583673.html

Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

cpufreq: SCMI: Don't validate the frequency table twice

The cpufreq core is already validating the CPU frequency table after
calling the ->init() callback of the cpufreq drivers and the drivers
don't need to do the same anymore. Though they need to set the
policy->freq_table field directly from the ->init() callback now.

Stop validating the frequency table from SCMI driver.

Signed-off-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>

cpufreq: scmi: add support for fast frequency switching

The cpufreq core provides option for drivers to implement fast_switch
callback which is invoked for frequency switching from interrupt context.

This patch adds support for fast_switch callback in SCMI cpufreq driver
by making use of polling based SCMI transfer. It also sets the flag
fast_switch_possible.

Cc: linux-pm@vger.kernel.org
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

cpufreq: add support for CPU DVFS based on SCMI message protocol

On some ARM based systems, a separate Cortex-M based System Control
Processor(SCP) provides the overall power, clock, reset and system
control including CPU DVFS. SCMI Message Protocol is used to
communicate with the SCP.

This patch adds a cpufreq driver for such systems using SCMI interface
to drive CPU DVFS.

Cc: linux-pm@vger.kernel.org
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>