From: Xiongfeng Wang wangxiongfeng2@huawei.com
mainline inclusion from mainline-v5.8-rc1 commit 54e74df5d76dea824c7c0c9d1b97150bf9b33793 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I88RXU CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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To add SW BOOST support for CPPC, we need to get the max frequency of boost mode and non-boost mode. ACPI spec 6.2 section 8.4.7.1 describes the following two CPC registers.
"Highest performance is the absolute maximum performance an individual processor may reach, assuming ideal conditions. This performance level may not be sustainable for long durations, and may only be achievable if other platform components are in a specific state; for example, it may require other processors be in an idle state.
Nominal Performance is the maximum sustained performance level of the processor, assuming ideal operating conditions. In absence of an external constraint (power, thermal, etc.) this is the performance level the platform is expected to be able to maintain continuously. All processors are expected to be able to sustain their nominal performance state simultaneously."
To add SW BOOST support for CPPC, we can use Highest Performance as the max performance in boost mode and Nominal Performance as the max performance in non-boost mode. If the Highest Performance is greater than the Nominal Performance, we assume SW BOOST is supported.
The current CPPC driver does not support SW BOOST and use 'Highest Performance' as the max performance the CPU can achieve. 'Nominal Performance' is used to convert 'performance' to 'frequency'. That means, if firmware enable boost and provide a value for Highest Performance which is greater than Nominal Performance, boost feature is enabled by default.
Because SW BOOST is disabled by default, so, after this patch, boost feature is disabled by default even if boost is enabled by firmware.
Signed-off-by: Xiongfeng Wang wangxiongfeng2@huawei.com Suggested-by: Viresh Kumar viresh.kumar@linaro.org Acked-by: Viresh Kumar viresh.kumar@linaro.org [ rjw: Subject ] Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Signed-off-by: Yu Liao liaoyu15@huawei.com --- drivers/cpufreq/cppc_cpufreq.c | 35 ++++++++++++++++++++++++++++++++-- 1 file changed, 33 insertions(+), 2 deletions(-)
diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c index 0a245f1caa95..15cffca10f1a 100644 --- a/drivers/cpufreq/cppc_cpufreq.c +++ b/drivers/cpufreq/cppc_cpufreq.c @@ -41,6 +41,7 @@ * requested etc. */ static struct cppc_cpudata **all_cpu_data; +static bool boost_supported;
struct cppc_workaround_oem_info { char oem_id[ACPI_OEM_ID_SIZE + 1]; @@ -314,7 +315,7 @@ static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy) * Section 8.4.7.1.1.5 of ACPI 6.1 spec) */ 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); + policy->max = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.nominal_perf);
/* * Set cpuinfo.min_freq to Lowest to make the full range of performance @@ -322,7 +323,7 @@ static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy) * nonlinear perf */ 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->cpuinfo.max_freq = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.nominal_perf);
policy->transition_delay_us = cppc_cpufreq_get_transition_delay_us(cpu_num); policy->shared_type = cpu->shared_type; @@ -347,6 +348,13 @@ static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
cpu->cur_policy = policy;
+ /* + * If 'highest_perf' is greater than 'nominal_perf', we assume CPU Boost + * is supported. + */ + if (cpu->perf_caps.highest_perf > cpu->perf_caps.nominal_perf) + boost_supported = true; + /* Set policy->cur to max now. The governors will adjust later. */ policy->cur = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.highest_perf); @@ -414,6 +422,28 @@ static unsigned int cppc_cpufreq_get_rate(unsigned int cpunum) return cppc_get_rate_from_fbctrs(cpu, fb_ctrs_t0, fb_ctrs_t1); }
+static int cppc_cpufreq_set_boost(struct cpufreq_policy *policy, int state) +{ + struct cppc_cpudata *cpudata; + int ret; + + if (!boost_supported) { + pr_err("BOOST not supported by CPU or firmware\n"); + return -EINVAL; + } + + cpudata = all_cpu_data[policy->cpu]; + if (state) + policy->max = cppc_cpufreq_perf_to_khz(cpudata, + cpudata->perf_caps.highest_perf); + else + policy->max = cppc_cpufreq_perf_to_khz(cpudata, + cpudata->perf_caps.nominal_perf); + policy->cpuinfo.max_freq = policy->max; + + return 0; +} + static struct cpufreq_driver cppc_cpufreq_driver = { .flags = CPUFREQ_CONST_LOOPS, .verify = cppc_verify_policy, @@ -421,6 +451,7 @@ static struct cpufreq_driver cppc_cpufreq_driver = { .get = cppc_cpufreq_get_rate, .init = cppc_cpufreq_cpu_init, .stop_cpu = cppc_cpufreq_stop_cpu, + .set_boost = cppc_cpufreq_set_boost, .name = "cppc_cpufreq", };