intel_pstate: Add num_pstates to sysfs
Add a sysfs interface to display the total number of supported
pstates. This value is independent of whether turbo has been
enabled or disabled.
Signed-off-by: Kristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/Documentation/cpu-freq/intel-pstate.txt b/Documentation/cpu-freq/intel-pstate.txt
index 7767ce6..6557507 100644
--- a/Documentation/cpu-freq/intel-pstate.txt
+++ b/Documentation/cpu-freq/intel-pstate.txt
@@ -41,6 +41,10 @@
is supported by hardware that is in the turbo range. This number
is independent of whether turbo has been disabled or not.
+ num_pstates: displays the number of pstates that are supported
+ by hardware. This number is independent of whether turbo has
+ been disabled or not.
+
For contemporary Intel processors, the frequency is controlled by the
processor itself and the P-states exposed to software are related to
performance levels. The idea that frequency can be set to a single
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index ed6dd7d..80ecc35 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -354,6 +354,17 @@
return sprintf(buf, "%u\n", turbo_pct);
}
+static ssize_t show_num_pstates(struct kobject *kobj,
+ struct attribute *attr, char *buf)
+{
+ struct cpudata *cpu;
+ int total;
+
+ cpu = all_cpu_data[0];
+ total = cpu->pstate.turbo_pstate - cpu->pstate.min_pstate + 1;
+ return sprintf(buf, "%u\n", total);
+}
+
static ssize_t show_no_turbo(struct kobject *kobj,
struct attribute *attr, char *buf)
{
@@ -435,12 +446,14 @@
define_one_global_rw(max_perf_pct);
define_one_global_rw(min_perf_pct);
define_one_global_ro(turbo_pct);
+define_one_global_ro(num_pstates);
static struct attribute *intel_pstate_attributes[] = {
&no_turbo.attr,
&max_perf_pct.attr,
&min_perf_pct.attr,
&turbo_pct.attr,
+ &num_pstates.attr,
NULL
};