On 8/23/25 1:01 PM, Sumit Gupta wrote:
> Add sysfs interfaces for Minimum Performance, Maximum Performance
> and Performance Limited Register in the cppc_cpufreq driver.
>
> Signed-off-by: Sumit Gupta <sumitg@xxxxxxxxxx>
> ---
> .../ABI/testing/sysfs-devices-system-cpu | 43 +++++++++++++++++++
> 1 file changed, 43 insertions(+)
>
> diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
> index ab8cd337f43a..4bce0dbc48c9 100644
> --- a/Documentation/ABI/testing/sysfs-devices-system-cpu
> +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
> @@ -327,6 +327,49 @@ Description: Energy performance preference
>
> This file is only present if the cppc-cpufreq driver is in use.
>
> +What: /sys/devices/system/cpu/cpuX/cpufreq/min_perf
> +Date: Aug 2025
> +Contact: linux-pm@xxxxxxxxxxxxxxx
> +Description: Minimum Performance
Preferably these 4 lines above use tab(s) after the ':' for indentation
instead of spaces. (in 3 places, i.e., each sysfs file entry).
> +
> + Read/write a 32 bits value from/to this file. This file
> + conveys the minimum performance level at which the platform
> + may run. Minimum performance may be set to any performance
> + value in the range [Lowest Performance, Highest Performance],
> + inclusive but must be set to a value that is less than or
> + equal to that specified by the Maximum Performance Register.
> +
> + Writing to this file only has meaning when Autonomous Selection
> + is enabled.
> +
> + This file is only present if the cppc-cpufreq driver is in use.
> +
> +What: /sys/devices/system/cpu/cpuX/cpufreq/max_perf
> +Date: Aug 2025
> +Contact: linux-pm@xxxxxxxxxxxxxxx
> +Description: Minimum Performance
> +
> + Read/write a 32 bits value from/to this file. This file conveys
> + the maximum performance level at which the platform may run.
> + Maximum performance may be set to any performance value in the
> + range [Lowest Performance, Highest Performance], inclusive.
> +
> + Writing to this file only has meaning when Autonomous Selection is
> + enabled.
> +
> + This file is only present if the cppc-cpufreq driver is in use.
> +
> +What: /sys/devices/system/cpu/cpuX/cpufreq/perf_limited
> +Date: Aug 2025
> +Contact: linux-pm@xxxxxxxxxxxxxxx
> +Description: Minimum Performance
> +
> + Read/write a 32 bits value from/to this file. This file indicates
> + to OSPM that an unpredictable event has limited processor
> + performance, and the delivered performance may be less than
> + desired/minimum performance.
> +
> + This file is only present if the cppc-cpufreq driver is in use.
>
> What: /sys/devices/system/cpu/cpu*/cache/index3/cache_disable_{0,1}
> Date: August 2008
Reviewed-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Thanks.
--
~Randy
