From 12753d71e8c5c3e716cedba23ddeed508da0bdc4 Mon Sep 17 00:00:00 2001 From: Meng Li Date: Fri, 19 Jan 2024 17:04:57 +0800 Subject: 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 Reviewed-by: Mario Limonciello Reviewed-by: Wyes Karny Reviewed-by: Perry Yuan Acked-by: Huang Rui Signed-off-by: Meng Li 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 --- drivers/acpi/cppc_acpi.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'drivers/acpi/cppc_acpi.c') 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 @@ -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. -- cgit v1.2.3