When I booted my RK3588 based system I noticed that cpufreq complained
about system clock:

[  +0.007211] cpufreq: cpufreq_online: CPU0: Running at unlisted initial frequency: 816000 KHz, changing to: 1008000 KHz

Then I realized that unit is displayed wrong: "KHz" instead of "kHz".

Signed-off-by: Marcin Juszkiewicz <marcin.juszkiewicz@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Link: https://patch.msgid.link/20240909095529.2325103-1-marcin.juszkiewicz@linaro.org
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

The current LATENCY_MULTIPLIER which has been around for nearly 20 years
causes rate_limit_us to be always in ms range.

On M1 mac mini I get 50 and 56us transition latency, but due to the 1000
multiplier we end up setting rate_limit_us to 50 and 56ms, which gets
capped into 2ms and was 10ms before e13aa799c2a6 ("cpufreq: Change
default transition delay to 2ms")

On Intel I5 system transition latency is 20us but due to the multiplier
we end up with 20ms that again is capped to 2ms.

Given how good modern hardware and how modern workloads require systems
to be more responsive to cater for sudden changes in workload (tasks
sleeping/wakeup/migrating, uclamp causing a sudden boost or cap) and
that 2ms is quarter of the time of 120Hz refresh rate system, drop the
old logic in favour of providing 50% headroom.

	rate_limit_us = 1.5 * latency.

I considered not adding any headroom which could mean that we can end up
with infinite back-to-back requests.

I also considered providing a constant headroom (e.g: 100us) assuming
that any h/w or f/w dealing with the request shouldn't require a large
headroom when transition_latency is actually high.

But for both cases I wasn't sure if h/w or f/w can end up being
overwhelmed dealing with the freq requests in a potentially busy system.
So I opted for providing 50% breathing room.

This is expected to impact schedutil only as the other user,
dbs_governor, takes the max(2*tick, transition_delay_us) and the former
was at least 2ms on 1ms TICK, which is equivalent to the max_delay_us
before applying this patch. For systems with TICK of 4ms, this value
would have almost always ended up with 8ms sampling rate.

For systems that report 0 transition latency, we still default to
returning 1ms as transition delay.

This helps in eliminating a source of latency for applying requests as
mentioned in [1]. For example if we have a 1ms tick, most systems will
miss sending an update at tick when updating the util_avg for a task/CPU
(rate_limit_us will be 2ms for most systems).

Link: https://lore.kernel.org/lkml/20240724212255.mfr2ybiv2j2uqek7@airbuntu/ # [1]
Link: https://lore.kernel.org/lkml/20240205022500.2232124-1-qyousef@layalina.io/
Signed-off-by: Qais Yousef <qyousef@layalina.io>
Link: https://patch.msgid.link/20240728192659.58115-1-qyousef@layalina.io
[ rjw: Subject edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

The behavior introduced in commit f37a4d6b4a2c ("cpufreq: Fix per-policy
boost behavior on SoCs using cpufreq_boost_set_sw()") sets up the boost
policy incorrectly when boost has been enabled by the platform firmware
initially even if a driver sets the policy up.

This is because policy_has_boost_freq() assumes that there is a frequency
table set up by the driver and that the boost frequencies are advertised
in that table. This assumption doesn't work for acpi-cpufreq or
amd-pstate. Only use this check to enable boost if it's not already
enabled instead of also disabling it if alreayd enabled.

Fixes: f37a4d6b4a2c ("cpufreq: Fix per-policy boost behavior on SoCs using cpufreq_boost_set_sw()")
Link: https://patch.msgid.link/20240626204723.6237-1-mario.limonciello@amd.com
Reviewed-by: Sibi Sankar <quic_sibis@quicinc.com>
Reviewed-by: Dhruva Gole <d-gole@ti.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Suggested-by: Viresh Kumar <viresh.kumar@linaro.org>
Suggested-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Since this function is supposed to return boost_enabled which is anyway
a bool type make sure that it's return value is also marked as bool.
This helps maintain better consistency in data types being used.

Signed-off-by: Dhruva Gole <d-gole@ti.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Link: https://patch.msgid.link/20240627060117.1809477-1-d-gole@ti.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Merge the second round of changes for amd-pstate in 6.11 from Mario
Limonciello:

"* Enables amd-pstate by default in "shared memory" designs without
   a dedicated MSR.
 * Adds extra infrastructure for debugging problems.
 * Bug fixes found for init/unload failure."

* tag 'amd-pstate-v6.11-2024-06-24' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/superm1/linux:
  cpufreq: simplify boolean parsing with kstrtobool in store function
  cpufreq: amd-pstate: Don't create attributes when registration fails
  cpufreq: amd-pstate: Make amd-pstate unit tests depend on amd-pstate
  cpufreq/amd-pstate: fix setting policy current frequency value
  cpufreq: amd-pstate: auto-load pstate driver by default
  cpufreq: amd-pstate: enable shared memory type CPPC by default
  cpufreq: amd-pstate: switch boot_cpu_has() to cpu_feature_enabled()
  Documentation: PM: amd-pstate: add guided mode to the Operation mode
  cpufreq: amd-pstate: add debug message while CPPC is supported and disabled by SBIOS
  cpufreq: amd-pstate: show CPPC debug message if CPPC is not supported
  cpufreq: amd-pstate: remove unused variable nominal_freq
  cpufreq: amd-pstate: optimize the initial frequency values verification
  cpufreq: amd-pstate: Allow users to write 'default' EPP string

Update the cpufreq store function to use kstrtobool for parsing boolean
values. This simplifies the code and improves readability by using a
standard kernel function for boolean string conversion.

Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Signed-off-by: Perry Yuan <perry.yuan@amd.com>
Link: https://lore.kernel.org/r/d392eba3bad1231776124c321cef8c184ce1482d.1718988436.git.perry.yuan@amd.com
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>

Replace sprintf() and scnprintf() with sysfs_emit() and sysfs_emit_at()
in the cpufreq core.

This ensures safer buffer handling and consistency with sysfs interfaces.

Update show_scaling_available_governors() and related functions for
compliance with the new API.

Signed-off-by: Perry Yuan <perry.yuan@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Link: https://patch.msgid.link/20240619081520.259971-1-perry.yuan@amd.com
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Pull power management updates from Rafael Wysocki:
 "These are mostly cpufreq updates, including a significant intel-pstate
  driver update and several amd-pstate improvements plus some updates of
  ARM cpufreq drivers, general fixes and cleanups.

  Also included are changes related to system sleep, power capping
  updates adding support for a new platform and a new hardware feature
  (among other things), a Samsung exynos-asv driver update allowing it
  to change its Energy Model after adjusting voltage, minor cpuidle and
  devfreq updates and a small documentation cleanup.

  Specifics:

   - Rework the handling of disabled turbo in the intel_pstate driver
     and make it update the maximum CPU frequency consistently
     regardless of the reason on top of a number of cleanups (Rafael
     Wysocki)

   - Add missing checks for NULL .exit() cpufreq driver callback to the
     cpufreq core (Viresh Kumar)

   - Prevent pulicy->max from going above the frequency QoS maximum
     value when cpufreq_frequency_table_verify() is used (Xuewen Yan)

   - Prevent a negative CPU number or frequency value from being printed
     if they are really large (Joshua Yeong)

   - Update MAINTAINERS entry for amd-pstate to add two new
     submaintainers and a designated reviewer (Huang Rui)

   - Clean up the amd-pstate driver and update its documentation
     (Gautham Shenoy)

   - Fix the highest frequency issue in the amd-pstate driver which
     limits performance (Perry Yuan)

   - Enable CPPC v2 for certain processors in the family 17H, as
     requested by TR40 processor users who expect improved performance
     and lower system temperature (Perry Yuan)

   - Change latency and delay values to be read from platform firmware
     firstly for more accurate timing (Perry Yuan)

   - A new quirk is introduced for supporting amd-pstate on legacy
     processors which either lack CPPC capability, or only only have
     CPPC v2 capability (Perry Yuan)

   - Sun50i cpufreq: Add support for opp_supported_hw, H616 platform and
     general cleanups (Andre Przywara, Martin Botka, Brandon Cheo Fusi,
     Dan Carpenter, Viresh Kumar)

   - CPPC cpufreq: Fix possible null pointer dereference (Aleksandr
     Mishin)

   - Eliminate uses of of_node_put() from cpufreq (Javier Carrasco,
     Shivani Gupta)

   - brcmstb-avs: ISO C90 forbids mixed declarations (Portia Stephens)

   - mediatek cpufreq: Add support for MT7988A (Sam Shih)

   - cpufreq-qcom-hw: Add SM4450 compatibles in DT bindings (Tengfei
     Fan)

   - Fix struct cpudata::epp_cached kernel-doc in the intel_pstate
     cpufreq driver (Jeff Johnson)

   - Fix kerneldoc description of ladder_do_selection() (Jeff Johnson)

   - Convert the cpuidle kirkwood driver to platform remove callback
     returning void (Yangtao Li)

   - Replace deprecated strncpy() with strscpy() in the hibernation core
     code (Justin Stitt)

   - Use %ps to simplify debug output in the core system-wide suspend
     and resume code (Len Brown)

   - Remove unnecessary else from device_init_wakeup() and make
     device_wakeup_disable() return void (Dhruva Gole)

   - Enable PMU support in the Intel TPMI RAPL driver (Zhang Rui)

   - Add support for ArrowLake-H platform to the Intel RAPL driver
     (Zhang Rui)

   - Avoid explicit cpumask allocation on stack in DTPM (Dawei Li)

   - Make the Samsung exynos-asv driver update the Energy Model after
     adjusting voltage on top of some preliminary changes of the OPP and
     Enery Model generic code (Lukasz Luba)

   - Remove a reference to a function that has been dropped from the
     power management documentation (Bjorn Helgaas)

   - Convert the platfrom remove callback to .remove_new for the
     exyno-nocp, exynos-ppmu, mtk-cci-devfreq, sun8i-a33-mbus, and
     rk3399_dmc devfreq drivers (Uwe Kleine-König)

   - Use DEFINE_SIMPLE_PM_OPS for exyno-bus.c driver (Anand Moon)"

* tag 'pm-6.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (68 commits)
  PM / devfreq: exynos: Use DEFINE_SIMPLE_DEV_PM_OPS for PM functions
  PM / devfreq: rk3399_dmc: Convert to platform remove callback returning void
  PM / devfreq: sun8i-a33-mbus: Convert to platform remove callback returning void
  PM / devfreq: mtk-cci: Convert to platform remove callback returning void
  PM / devfreq: exynos-ppmu: Convert to platform remove callback returning void
  PM / devfreq: exynos-nocp: Convert to platform remove callback returning void
  cpufreq: amd-pstate: fix the highest frequency issue which limits performance
  cpufreq: intel_pstate: fix struct cpudata::epp_cached kernel-doc
  cpuidle: ladder: fix ladder_do_selection() kernel-doc
  powercap: intel_rapl_tpmi: Enable PMU support
  powercap: intel_rapl: Introduce APIs for PMU support
  PM: hibernate: replace deprecated strncpy() with strscpy()
  cpufreq: Fix up printing large CPU numbers and frequency values
  MAINTAINERS: cpufreq: amd-pstate: Add co-maintainers and reviewer
  cpufreq: amd-pstate: remove unused variable lowest_nonlinear_freq
  cpufreq: amd-pstate: fix code format problems
  cpufreq: amd-pstate: Add quirk for the pstate CPPC capabilities missing
  cppc_acpi: print error message if CPPC is unsupported
  cpufreq: amd-pstate: get transition delay and latency value from ACPI tables
  cpufreq: amd-pstate: Bail out if min/max/nominal_freq is 0
  ...

Provide to the scheduler a feedback about the temporary max available
capacity. Unlike arch_update_thermal_pressure(), this doesn't need to be
filtered as the pressure will happen for dozens of ms or more.

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Lukasz Luba <lukasz.luba@arm.com>
Reviewed-by: Qais Yousef <qyousef@layalina.io>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Reviewed-by: Dhruva Gole <d-gole@ti.com>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Link: https://lore.kernel.org/r/20240326091616.3696851-2-vincent.guittot@linaro.org