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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>
This commit is contained in:
Meng Li 2024-01-19 17:04:57 +08:00 committed by Rafael J. Wysocki
parent 3598e577d1
commit 12753d71e8
2 changed files with 18 additions and 0 deletions
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13
drivers/acpi/cppc_acpi.c
View File

@ -1157,6 +1157,19 @@ int cppc_get_nominal_perf(int cpunum, u64 *nominal_perf)
return cppc_get_perf(cpunum, NOMINAL_PERF, 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.

5
include/acpi/cppc_acpi.h
View File

@ -139,6 +139,7 @@ struct cppc_cpudata {
#ifdef CONFIG_ACPI_CPPC_LIB
extern int cppc_get_desired_perf(int cpunum, u64 *desired_perf);
extern int cppc_get_nominal_perf(int cpunum, u64 *nominal_perf);
extern int cppc_get_highest_perf(int cpunum, u64 *highest_perf);
extern int cppc_get_perf_ctrs(int cpu, struct cppc_perf_fb_ctrs *perf_fb_ctrs);
extern int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls);
extern int cppc_set_enable(int cpu, bool enable);
@ -167,6 +168,10 @@ static inline int cppc_get_nominal_perf(int cpunum, u64 *nominal_perf)
{
return -ENOTSUPP;
}
static inline int cppc_get_highest_perf(int cpunum, u64 *highest_perf)
{
return -ENOTSUPP;
}
static inline int cppc_get_perf_ctrs(int cpu, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
{
return -ENOTSUPP;