diff options
Diffstat (limited to 'drivers/cpufreq/cppc_cpufreq.c')
| -rw-r--r-- | drivers/cpufreq/cppc_cpufreq.c | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c index a9d3eec32795..30f302149730 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", |