intel_pstate: Knights Landing support
1. Add Knights Landing (KNL) CPUID to the list of CPUIDs supported by
the intel_pstate driver.
2. Add a new cpu_default structure for KNL since KNL has a slightly
different mechanism to get turbo pstates from MSRs.
Signed-off-by: Dasaratharaman Chandramouli <dasaratharaman.chandramouli@intel.com>
Signed-off-by: Kristen Carlson Accardi <kristen@linux.intel.com>
[ rjw: Subject and changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index 8006d86..c5b81be 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -614,6 +614,19 @@
wrmsrl_on_cpu(cpudata->cpu, MSR_IA32_PERF_CTL, val);
}
+static int knl_get_turbo_pstate(void)
+{
+ u64 value;
+ int nont, ret;
+
+ rdmsrl(MSR_NHM_TURBO_RATIO_LIMIT, value);
+ nont = core_get_max_pstate();
+ ret = (((value) >> 8) & 0xFF);
+ if (ret <= nont)
+ ret = nont;
+ return ret;
+}
+
static struct cpu_defaults core_params = {
.pid_policy = {
.sample_rate_ms = 10,
@@ -651,6 +664,23 @@
},
};
+static struct cpu_defaults knl_params = {
+ .pid_policy = {
+ .sample_rate_ms = 10,
+ .deadband = 0,
+ .setpoint = 97,
+ .p_gain_pct = 20,
+ .d_gain_pct = 0,
+ .i_gain_pct = 0,
+ },
+ .funcs = {
+ .get_max = core_get_max_pstate,
+ .get_min = core_get_min_pstate,
+ .get_turbo = knl_get_turbo_pstate,
+ .set = core_set_pstate,
+ },
+};
+
static void intel_pstate_get_min_max(struct cpudata *cpu, int *min, int *max)
{
int max_perf = cpu->pstate.turbo_pstate;
@@ -865,6 +895,7 @@
ICPU(0x4e, core_params),
ICPU(0x4f, core_params),
ICPU(0x56, core_params),
+ ICPU(0x57, knl_params),
{}
};
MODULE_DEVICE_TABLE(x86cpu, intel_pstate_cpu_ids);
