diff options
| -rw-r--r-- | Documentation/devicetree/bindings/arm/cpus.txt | 14 | ||||
| -rw-r--r-- | arch/arm64/kernel/topology.c | 30 |
2 files changed, 36 insertions, 8 deletions
diff --git a/Documentation/devicetree/bindings/arm/cpus.txt b/Documentation/devicetree/bindings/arm/cpus.txt index 3a07a87fef20..71314d5ab0d8 100644 --- a/Documentation/devicetree/bindings/arm/cpus.txt +++ b/Documentation/devicetree/bindings/arm/cpus.txt @@ -212,6 +212,20 @@ nodes to be present and contain the properties described below. property identifying a 64-bit zero-initialised memory location. + - efficiency + Usage: optional. + Value type: <u32> + Definition: + # Specifies the CPU efficiency. The CPU efficiency is + a unit less number and it is intended to show relative + performance of CPUs when normalized for clock frequency + (instructions per cycle performance). + + The efficiency of a CPU can vary across SoCs depending + on the cache size, bus interconnect frequencies etc. + This value overrides the default efficiency value + defined for the corresponding CPU architecture. + - qcom,saw Usage: required for systems that have an "enable-method" property value of "qcom,kpss-acc-v1" or diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c index e562e0f43a42..67fc833a26af 100644 --- a/arch/arm64/kernel/topology.c +++ b/arch/arm64/kernel/topology.c @@ -278,6 +278,7 @@ static void __init parse_dt_cpu_power(void) for_each_possible_cpu(cpu) { const u32 *rate; int len; + u32 efficiency; /* Too early to use cpu->of_node */ cn = of_get_cpu_node(cpu, NULL); @@ -286,16 +287,29 @@ static void __init parse_dt_cpu_power(void) continue; } - for (cpu_eff = table_efficiency; cpu_eff->compatible; cpu_eff++) - if (of_device_is_compatible(cn, cpu_eff->compatible)) - break; + /* + * The CPU efficiency value passed from the device tree + * overrides the value defined in the table_efficiency[] + */ + if (of_property_read_u32(cn, "efficiency", &efficiency) < 0) { - if (cpu_eff->compatible == NULL) { - pr_warn("%s: Unknown CPU type\n", cn->full_name); - continue; + for (cpu_eff = table_efficiency; + cpu_eff->compatible; cpu_eff++) + + if (of_device_is_compatible(cn, + cpu_eff->compatible)) + break; + + if (cpu_eff->compatible == NULL) { + pr_warn("%s: Unknown CPU type\n", + cn->full_name); + continue; + } + + efficiency = cpu_eff->efficiency; } - per_cpu(cpu_efficiency, cpu) = cpu_eff->efficiency; + per_cpu(cpu_efficiency, cpu) = efficiency; rate = of_get_property(cn, "clock-frequency", &len); if (!rate || len != 4) { @@ -304,7 +318,7 @@ static void __init parse_dt_cpu_power(void) continue; } - capacity = ((be32_to_cpup(rate)) >> 20) * cpu_eff->efficiency; + capacity = ((be32_to_cpup(rate)) >> 20) * efficiency; /* Save min capacity of the system */ if (capacity < min_capacity) |