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| author | Meng Li <li.meng@amd.com> | 2024-01-19 12:04:57 +0300 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2024-01-31 16:54:50 +0300 |
| commit | 12753d71e8c5c3e716cedba23ddeed508da0bdc4 (patch) | |
| tree | 20837471f70acf1f35fc35e7cc7cd53bffa0b637 /drivers/acpi/cppc_acpi.c | |
| parent | 3598e577d1290008dcc753a015675fe617cdde45 (diff) | |
| download | linux-12753d71e8c5c3e716cedba23ddeed508da0bdc4.tar.xz | |
ACPI: CPPC: Add helper to get the highest performance value
Add support for getting the highest performance to the
generic CPPC driver. This enables downstream drivers
such as amd-pstate to discover and use these values.
Refer to Chapter 8.4.6.1.1.1. Highest Performance of ACPI
Specification 6.5 for details on continuous performance control
of CPPC (linked below).
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Wyes Karny <wyes.karny@amd.com>
Reviewed-by: Perry Yuan <perry.yuan@amd.com>
Acked-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Meng Li <li.meng@amd.com>
Link: https://uefi.org/specs/ACPI/6.5/08_Processor_Configuration_and_Control.html?highlight=cppc#highest-performance
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/acpi/cppc_acpi.c')
| -rw-r--r-- | drivers/acpi/cppc_acpi.c | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c index d155a86a8614..a50e70abdf19 100644 --- a/drivers/acpi/cppc_acpi.c +++ b/drivers/acpi/cppc_acpi.c @@ -1158,6 +1158,19 @@ int cppc_get_nominal_perf(int cpunum, u64 *nominal_perf) } /** + * cppc_get_highest_perf - Get the highest performance register value. + * @cpunum: CPU from which to get highest performance. + * @highest_perf: Return address. + * + * Return: 0 for success, -EIO otherwise. + */ +int cppc_get_highest_perf(int cpunum, u64 *highest_perf) +{ + return cppc_get_perf(cpunum, HIGHEST_PERF, highest_perf); +} +EXPORT_SYMBOL_GPL(cppc_get_highest_perf); + +/** * cppc_get_epp_perf - Get the epp register value. * @cpunum: CPU from which to get epp preference value. * @epp_perf: Return address. |