| Message ID | 1531375675-52623-1-git-send-email-george.cherian@cavium.com (mailing list archive) |
|---|---|
| State | Mainlined |
| Delegated to: | Rafael Wysocki |
| Headers | show |
Hi George, This version looks good. Thanks! On 7/12/2018 12:07 AM, George Cherian wrote: > Per Section 8.4.7.1.3 of ACPI 6.2, The platform provides performance > feedback via set of performance counters. To determine the actual > performance level delivered over time, OSPM may read a set of > performance counters from the Reference Performance Counter Register > and the Delivered Performance Counter Register. > > OSPM calculates the delivered performance over a given time period by > taking a beginning and ending snapshot of both the reference and > delivered performance counters, and calculating: > > delivered_perf = reference_perf X (delta of delivered_perf counter / delta of reference_perf counter). > > Implement the above and hook this to the cpufreq->get method. > > Signed-off-by: George Cherian <george.cherian@cavium.com> > Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Acked-by: Prashanth Prakash <pprakash@codeaurora.org>
On Saturday, July 14, 2018 12:20:43 AM CEST Prakash, Prashanth wrote: > Hi George, > > This version looks good. Thanks! > > On 7/12/2018 12:07 AM, George Cherian wrote: > > Per Section 8.4.7.1.3 of ACPI 6.2, The platform provides performance > > feedback via set of performance counters. To determine the actual > > performance level delivered over time, OSPM may read a set of > > performance counters from the Reference Performance Counter Register > > and the Delivered Performance Counter Register. > > > > OSPM calculates the delivered performance over a given time period by > > taking a beginning and ending snapshot of both the reference and > > delivered performance counters, and calculating: > > > > delivered_perf = reference_perf X (delta of delivered_perf counter / delta of reference_perf counter). > > > > Implement the above and hook this to the cpufreq->get method. > > > > Signed-off-by: George Cherian <george.cherian@cavium.com> > > Acked-by: Viresh Kumar <viresh.kumar@linaro.org> > Acked-by: Prashanth Prakash <pprakash@codeaurora.org> > Patch applied, thanks!
diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c index a9d3eec..30f3021 100644 --- a/drivers/cpufreq/cppc_cpufreq.c +++ b/drivers/cpufreq/cppc_cpufreq.c @@ -296,10 +296,62 @@ static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy) return ret; } +static inline u64 get_delta(u64 t1, u64 t0) +{ + if (t1 > t0 || t0 > ~(u32)0) + return t1 - t0; + + return (u32)t1 - (u32)t0; +} + +static int cppc_get_rate_from_fbctrs(struct cppc_cpudata *cpu, + struct cppc_perf_fb_ctrs fb_ctrs_t0, + struct cppc_perf_fb_ctrs fb_ctrs_t1) +{ + u64 delta_reference, delta_delivered; + u64 reference_perf, delivered_perf; + + reference_perf = fb_ctrs_t0.reference_perf; + + delta_reference = get_delta(fb_ctrs_t1.reference, + fb_ctrs_t0.reference); + delta_delivered = get_delta(fb_ctrs_t1.delivered, + fb_ctrs_t0.delivered); + + /* Check to avoid divide-by zero */ + if (delta_reference || delta_delivered) + delivered_perf = (reference_perf * delta_delivered) / + delta_reference; + else + delivered_perf = cpu->perf_ctrls.desired_perf; + + return cppc_cpufreq_perf_to_khz(cpu, delivered_perf); +} + +static unsigned int cppc_cpufreq_get_rate(unsigned int cpunum) +{ + struct cppc_perf_fb_ctrs fb_ctrs_t0 = {0}, fb_ctrs_t1 = {0}; + struct cppc_cpudata *cpu = all_cpu_data[cpunum]; + int ret; + + ret = cppc_get_perf_ctrs(cpunum, &fb_ctrs_t0); + if (ret) + return ret; + + udelay(2); /* 2usec delay between sampling */ + + ret = cppc_get_perf_ctrs(cpunum, &fb_ctrs_t1); + if (ret) + return ret; + + return cppc_get_rate_from_fbctrs(cpu, fb_ctrs_t0, fb_ctrs_t1); +} + static struct cpufreq_driver cppc_cpufreq_driver = { .flags = CPUFREQ_CONST_LOOPS, .verify = cppc_verify_policy, .target = cppc_cpufreq_set_target, + .get = cppc_cpufreq_get_rate, .init = cppc_cpufreq_cpu_init, .stop_cpu = cppc_cpufreq_stop_cpu, .name = "cppc_cpufreq",