linux/drivers/cpufreq/cppc_cpufreq.c, branch v6.17

cpufreq: CPPC: Mark driver with NEED_UPDATE_LIMITS flag

2025-07-22T10:13:12Z

AMU counters on certain CPPC-based platforms tend to yield inaccurate delivered performance measurements on systems that are idle/mostly idle. This results in an inaccurate frequency being stored by cpufreq in its policy structure when the CPU is brought online. [1] Consequently, if the userspace governor tries to set the frequency to a new value, there is a possibility that it would be the erroneous value stored earlier. In such a scenario, cpufreq would assume that the requested frequency has already been set and return early, resulting in the correct/new frequency request never making it to the hardware. Since the operating frequency is liable to this sort of inconsistency, mark the CPPC driver with CPUFREQ_NEED_UPDATE_LIMITS so that it is always invoked when a target frequency update is requested. Link: https://lore.kernel.org/linux-pm/20250619000925.415528-3-pmalani@google.com/ [1] Suggested-by: Rafael J. Wysocki Signed-off-by: Prashant Malani Acked-by: Viresh Kumar Link: https://patch.msgid.link/20250722055611.130574-2-pmalani@google.com Signed-off-by: Rafael J. Wysocki

cpufreq: CPPC: Remove forward declaration of cppc_cpufreq_register_em()

2025-06-18T19:03:52Z

cppc_cpufreq_register_em() is only used in populate_efficiency_class(). A forward declaration of it is not necessary. Move cppc_cpufreq_register_em() in front of populate_efficiency_class() and remove the forward declaration of cppc_cpufreq_register_em(). No functional change. Signed-off-by: Lifeng Zheng Link: https://patch.msgid.link/20250526113057.3086513-4-zhenglifeng1@huawei.com [ rjw: Changelog edits ] Signed-off-by: Rafael J. Wysocki

cpufreq: CPPC: Do not return a value from populate_efficiency_class()

2025-06-18T19:03:52Z

The return value of populate_efficiency_class() is never needed and the result of it doesn't affect the initialization of cppc_cpufreq. It makes more sense to change it into a void function. Signed-off-by: Lifeng Zheng Link: https://patch.msgid.link/20250526113057.3086513-3-zhenglifeng1@huawei.com [ rjw: Subject and changelog edits ] Signed-off-by: Rafael J. Wysocki

cpufreq: CPPC: Remove cpu_data_list

2025-06-18T19:03:52Z

After commit a28b2bfc099c ("cppc_cpufreq: replace per-cpu data array with a list"), cpu_data can be got from policy->driver_data, so cpu_data_list is not actually needed and can be removed. Signed-off-by: Lifeng Zheng Link: https://patch.msgid.link/20250526113057.3086513-2-zhenglifeng1@huawei.com Signed-off-by: Rafael J. Wysocki

cpufreq: CPPC: Add support for autonomous selection

2025-05-21T20:47:44Z

Add sysfs interfaces for CPPC autonomous selection in the cppc_cpufreq driver. Signed-off-by: Lifeng Zheng Reviewed-by: Sumit Gupta Acked-by: Viresh Kumar Link: https://patch.msgid.link/20250507031941.2812701-1-zhenglifeng1@huawei.com [ rjw: Subject edits ] Signed-off-by: Rafael J. Wysocki

cpufreq: cppc: Fix invalid return value in .get() callback

2025-04-16T08:07:44Z

Returning a negative error code in a function with an unsigned return type is a pretty bad idea. It is probably worse when the justification for the change is "our static analisys tool found it". Fixes: cf7de25878a1 ("cppc_cpufreq: Fix possible null pointer dereference") Signed-off-by: Marc Zyngier Cc: "Rafael J. Wysocki" Cc: Viresh Kumar Reviewed-by: Lifeng Zheng Signed-off-by: Viresh Kumar

cpufreq: cppc: Set policy->boost_supported

2025-02-07T04:15:15Z

With a later commit, the cpufreq core will call the ->set_boost() callback only if the policy supports boost frequency. The boost_supported flag is set by the cpufreq core if policy->freq_table is set and one or more boost frequencies are present. For other drivers, the flag must be set explicitly. With this, the local variable boost_supported isn't required anymore. Signed-off-by: Viresh Kumar

cpufreq: CPPC: Fix wrong max_freq in policy initialization

2025-01-23T20:06:33Z

In policy initialization, policy->max and policy->cpuinfo.max_freq are always set to the value calculated from caps->nominal_perf. This will cause the frequency stay on base frequency even if the policy is already boosted when a CPU is going online. Fix this by using policy->boost_enabled to determine which value should be set. Signed-off-by: Lifeng Zheng Acked-by: Viresh Kumar Link: https://patch.msgid.link/20250117101457.1530653-4-zhenglifeng1@huawei.com [ rjw: Changelog edits ] Signed-off-by: Rafael J. Wysocki

treewide: Introduce kthread_run_worker[_on_cpu]()

2025-01-08T17:15:03Z

kthread_create() creates a kthread without running it yet. kthread_run() creates a kthread and runs it. On the other hand, kthread_create_worker() creates a kthread worker and runs it. This difference in behaviours is confusing. Also there is no way to create a kthread worker and affine it using kthread_bind_mask() or kthread_affine_preferred() before starting it. Consolidate the behaviours and introduce kthread_run_worker[_on_cpu]() that behaves just like kthread_run(). kthread_create_worker[_on_cpu]() will now only create a kthread worker without starting it. Signed-off-by: Frederic Weisbecker Signed-off-by: Dan Carpenter

Merge tag 'cpufreq-arm-updates-6.13' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/vireshk/pm

2024-11-19T20:35:14Z

Merge ARM cpufreq updates for 6.13 from Viresh Kumar: "- Add virtual cpufreq driver for guest kernels (David Dai). - Minor cleanup to various cpufreq drivers (Andy Shevchenko, Dhruva Gole, Jie Zhan, Jinjie Ruan, Shuosheng Huang, Sibi Sankar, and Yuan Can). - Revert "cpufreq: brcmstb-avs-cpufreq: Fix initial command check" (Colin Ian King). - Improve DT bindings for qcom-hw driver (Dmitry Baryshkov, Konrad Dybcio, and Nikunj Kela)." * tag 'cpufreq-arm-updates-6.13' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/vireshk/pm: arm64: dts: qcom: sc8180x: Add a SoC-specific compatible to cpufreq-hw dt-bindings: cpufreq: cpufreq-qcom-hw: Add SC8180X compatible cpufreq: sun50i: add a100 cpufreq support cpufreq: mediatek-hw: Fix wrong return value in mtk_cpufreq_get_cpu_power() cpufreq: CPPC: Fix wrong return value in cppc_get_cpu_power() cpufreq: CPPC: Fix wrong return value in cppc_get_cpu_cost() cpufreq: loongson3: Check for error code from devm_mutex_init() call cpufreq: scmi: Fix cleanup path when boost enablement fails cpufreq: CPPC: Fix possible null-ptr-deref for cppc_get_cpu_cost() cpufreq: CPPC: Fix possible null-ptr-deref for cpufreq_cpu_get_raw() Revert "cpufreq: brcmstb-avs-cpufreq: Fix initial command check" dt-bindings: cpufreq: cpufreq-qcom-hw: Add SAR2130P compatible cpufreq: add virtual-cpufreq driver dt-bindings: cpufreq: add virtual cpufreq device cpufreq: loongson2: Unregister platform_driver on failure cpufreq: ti-cpufreq: Remove revision offsets in AM62 family cpufreq: ti-cpufreq: Allow backward compatibility for efuse syscon cppc_cpufreq: Remove HiSilicon CPPC workaround cppc_cpufreq: Use desired perf if feedback ctrs are 0 or unchanged dt-bindings: cpufreq: qcom-hw: document support for SA8255p