Messages in this thread | | | Date | Wed, 20 May 2020 10:30:14 +0530 | From | Viresh Kumar <> | Subject | Re: [RFC PATCH v3 2/2] CPPC: add support for SW BOOST |
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On 19-05-20, 19:41, Xiongfeng Wang wrote: > 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 describe > 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> > --- > drivers/cpufreq/cppc_cpufreq.c | 39 +++++++++++++++++++++++++++++++++++++-- > 1 file changed, 37 insertions(+), 2 deletions(-) > > diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c > index bda0b24..792ed9e 100644 > --- a/drivers/cpufreq/cppc_cpufreq.c > +++ b/drivers/cpufreq/cppc_cpufreq.c > @@ -37,6 +37,7 @@ > * 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]; > @@ -310,7 +311,7 @@ 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 > @@ -318,7 +319,7 @@ 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; > @@ -343,6 +344,13 @@ 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); > @@ -410,6 +418,32 @@ 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 = 0;
No need to initialize this.
> + > + 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; > + > + ret = freq_qos_update_request(policy->max_freq_req, policy->max); > + if (ret < 0) > + return ret; > + > + return 0; > +} > + > static struct cpufreq_driver cppc_cpufreq_driver = { > .flags = CPUFREQ_CONST_LOOPS, > .verify = cppc_verify_policy, > @@ -417,6 +451,7 @@ static unsigned int cppc_cpufreq_get_rate(unsigned int cpunum) > .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", > }; > > -- > 1.7.12.4
-- viresh
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