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x86/amd: Use heterogeneous core topology for identifying boost numerator

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AMD heterogeneous designs include two types of cores:

 * Performance
 * Efficiency

Each core type has different highest performance values configured by the
platform.  Drivers such as amd_pstate need to identify the type of core to
correctly set an appropriate boost numerator to calculate the maximum
frequency.

X86_FEATURE_AMD_HETEROGENEOUS_CORES is used to identify whether the SoC
supports heterogeneous core type by reading CPUID leaf Fn_0x80000026.

On performance cores the scaling factor of 196 is used.  On efficiency cores
the scaling factor is the value reported as the highest perf.  Efficiency
cores have the same preferred core rankings.

Suggested-by: Perry Yuan <perry.yuan@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20241025171459.1093-6-mario.limonciello@amd.com
This commit is contained in:
Mario Limonciello
2024-10-25 12:14:59 -05:00
committed by Borislav Petkov (AMD)
parent 45239ba39a
commit 3eef25ab0d
1 changed files with 23 additions and 0 deletions
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arch/x86/kernel/acpi/cppc.c
+23
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@@ -234,8 +234,10 @@ EXPORT_SYMBOL_GPL(amd_detect_prefcore);
*/
int amd_get_boost_ratio_numerator(unsigned int cpu, u64 *numerator)
{
enum x86_topology_cpu_type core_type = get_topology_cpu_type(&cpu_data(cpu));
bool prefcore;
int ret;
u32 tmp;
ret = amd_detect_prefcore(&prefcore);
if (ret)
@@ -261,6 +263,27 @@ int amd_get_boost_ratio_numerator(unsigned int cpu, u64 *numerator)
break;
}
}
/* detect if running on heterogeneous design */
if (cpu_feature_enabled(X86_FEATURE_AMD_HETEROGENEOUS_CORES)) {
switch (core_type) {
case TOPO_CPU_TYPE_UNKNOWN:
pr_warn("Undefined core type found for cpu %d\n", cpu);
break;
case TOPO_CPU_TYPE_PERFORMANCE:
/* use the max scale for performance cores */
*numerator = CPPC_HIGHEST_PERF_PERFORMANCE;
return 0;
case TOPO_CPU_TYPE_EFFICIENCY:
/* use the highest perf value for efficiency cores */
ret = amd_get_highest_perf(cpu, &tmp);
if (ret)
return ret;
*numerator = tmp;
return 0;
}
}
*numerator = CPPC_HIGHEST_PERF_PREFCORE;
return 0;