diff options
Diffstat (limited to 'drivers/cpufreq')
| -rw-r--r-- | drivers/cpufreq/cppc_cpufreq.c | 80 |
1 files changed, 68 insertions, 12 deletions
diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c index b15115a48775..3464580ac3ca 100644 --- a/drivers/cpufreq/cppc_cpufreq.c +++ b/drivers/cpufreq/cppc_cpufreq.c @@ -42,9 +42,6 @@ */ static struct cppc_cpudata **all_cpu_data; -/* Capture the max KHz from DMI */ -static u64 cppc_dmi_max_khz; - /* Callback function used to retrieve the max frequency from DMI */ static void cppc_find_dmi_mhz(const struct dmi_header *dm, void *private) { @@ -75,6 +72,64 @@ static u64 cppc_get_dmi_max_khz(void) return (1000 * mhz); } +/* + * If CPPC lowest_freq and nominal_freq registers are exposed then we can + * use them to convert perf to freq and vice versa + * + * If the perf/freq point lies between Nominal and Lowest, we can treat + * (Low perf, Low freq) and (Nom Perf, Nom freq) as 2D co-ordinates of a line + * and extrapolate the rest + * For perf/freq > Nominal, we use the ratio perf:freq at Nominal for conversion + */ +static unsigned int cppc_cpufreq_perf_to_khz(struct cppc_cpudata *cpu, + unsigned int perf) +{ + static u64 max_khz; + struct cppc_perf_caps *caps = &cpu->perf_caps; + u64 mul, div; + + if (caps->lowest_freq && caps->nominal_freq) { + if (perf >= caps->nominal_perf) { + mul = caps->nominal_freq; + div = caps->nominal_perf; + } else { + mul = caps->nominal_freq - caps->lowest_freq; + div = caps->nominal_perf - caps->lowest_perf; + } + } else { + if (!max_khz) + max_khz = cppc_get_dmi_max_khz(); + mul = max_khz; + div = cpu->perf_caps.highest_perf; + } + return (u64)perf * mul / div; +} + +static unsigned int cppc_cpufreq_khz_to_perf(struct cppc_cpudata *cpu, + unsigned int freq) +{ + static u64 max_khz; + struct cppc_perf_caps *caps = &cpu->perf_caps; + u64 mul, div; + + if (caps->lowest_freq && caps->nominal_freq) { + if (freq >= caps->nominal_freq) { + mul = caps->nominal_perf; + div = caps->nominal_freq; + } else { + mul = caps->lowest_perf; + div = caps->lowest_freq; + } + } else { + if (!max_khz) + max_khz = cppc_get_dmi_max_khz(); + mul = cpu->perf_caps.highest_perf; + div = max_khz; + } + + return (u64)freq * mul / div; +} + static int cppc_cpufreq_set_target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation) @@ -86,7 +141,7 @@ static int cppc_cpufreq_set_target(struct cpufreq_policy *policy, cpu = all_cpu_data[policy->cpu]; - desired_perf = (u64)target_freq * cpu->perf_caps.highest_perf / cppc_dmi_max_khz; + desired_perf = cppc_cpufreq_khz_to_perf(cpu, target_freq); /* Return if it is exactly the same perf */ if (desired_perf == cpu->perf_ctrls.desired_perf) return ret; @@ -186,24 +241,24 @@ static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy) return ret; } - cppc_dmi_max_khz = cppc_get_dmi_max_khz(); + /* Convert the lowest and nominal freq from MHz to KHz */ + cpu->perf_caps.lowest_freq *= 1000; + cpu->perf_caps.nominal_freq *= 1000; /* * Set min to lowest nonlinear perf to avoid any efficiency penalty (see * Section 8.4.7.1.1.5 of ACPI 6.1 spec) */ - policy->min = cpu->perf_caps.lowest_nonlinear_perf * cppc_dmi_max_khz / - cpu->perf_caps.highest_perf; - policy->max = cppc_dmi_max_khz; + policy->min = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.lowest_nonlinear_perf); + policy->max = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.highest_perf); /* * Set cpuinfo.min_freq to Lowest to make the full range of performance * available if userspace wants to use any perf between lowest & lowest * nonlinear perf */ - policy->cpuinfo.min_freq = cpu->perf_caps.lowest_perf * cppc_dmi_max_khz / - cpu->perf_caps.highest_perf; - policy->cpuinfo.max_freq = cppc_dmi_max_khz; + policy->cpuinfo.min_freq = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.lowest_perf); + policy->cpuinfo.max_freq = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.highest_perf); policy->transition_delay_us = cppc_cpufreq_get_transition_delay_us(cpu_num); policy->shared_type = cpu->shared_type; @@ -229,7 +284,8 @@ static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy) cpu->cur_policy = policy; /* Set policy->cur to max now. The governors will adjust later. */ - policy->cur = cppc_dmi_max_khz; + policy->cur = cppc_cpufreq_perf_to_khz(cpu, + cpu->perf_caps.highest_perf); cpu->perf_ctrls.desired_perf = cpu->perf_caps.highest_perf; ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls); |