Use CPPC v3 entries to convert the abstract processor performance to
processor frequency in KHz.
Signed-off-by: Prashanth Prakash <pprakash@xxxxxxxxxxxxxx>
Cc: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
---
drivers/cpufreq/cppc_cpufreq.c | 84 ++++++++++++++++++++++++++++++++++++------
1 file changed, 72 insertions(+), 12 deletions(-)
diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
index 8300a9f..1b8ff9c 100644
--- a/drivers/cpufreq/cppc_cpufreq.c
+++ b/drivers/cpufreq/cppc_cpufreq.c
@@ -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 +198,28 @@ 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->cpuinfo.transition_latency = cppc_get_transition_latency(cpu_num);
policy->transition_delay_us = cppc_get_transition_latency(cpu_num) /
@@ -178,7 +237,8 @@ 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);
--
Qualcomm Datacenter Technologies on behalf of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.
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