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cpufreq / CPPC: Support for CPPC v3 

Use CPPC v3 entries to convert the abstract processor performance to
processor frequency in KHz.

Signed-off-by: Prashanth Prakash <pprakash@codeaurora.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
hifive-unleashed-5.1
Prashanth Prakash 2018-04-04 12:14:52 -06:00 committed by Rafael J. Wysocki
parent 6fa12d584d
commit 256f19d212
1 changed files with 68 additions and 12 deletions
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80
drivers/cpufreq/cppc_cpufreq.c
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@ -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;
@ -143,24 +198,24 @@ 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_get_transition_latency(cpu_num) /
NSEC_PER_USEC;
@ -187,7 +242,8 @@ 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);