[PATCH v4 14/22] cpupower: add the function to check amd-pstate enabled

[Huang Rui]

The processor with amd-pstate function also supports legacy ACPI
hardware P-States feature as well. Once driver sets amd-pstate eanbled,
the processor will respond the finer grain amd-pstate feature instead of
legacy ACPI P-States. So it introduces the cpupower_amd_pstate_enabled()
to check whether the current kernel enables amd-pstate or acpi-cpufreq
module.

Signed-off-by: Huang Rui <ray.huang@xxxxxxx>
---
 tools/power/cpupower/utils/helpers/helpers.h | 10 ++++++++++
 tools/power/cpupower/utils/helpers/misc.c    | 18 ++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/tools/power/cpupower/utils/helpers/helpers.h b/tools/power/cpupower/utils/helpers/helpers.h
index b4813efdfb00..e03cc97297aa 100644
--- a/tools/power/cpupower/utils/helpers/helpers.h
+++ b/tools/power/cpupower/utils/helpers/helpers.h
@@ -11,6 +11,7 @@
 
 #include <libintl.h>
 #include <locale.h>
+#include <stdbool.h>
 
 #include "helpers/bitmask.h"
 #include <cpupower.h>
@@ -136,6 +137,12 @@ extern int decode_pstates(unsigned int cpu, int boost_states,
 
 extern int cpufreq_has_boost_support(unsigned int cpu, int *support,
 				     int *active, int * states);
+
+/* AMD P-States stuff **************************/
+extern bool cpupower_amd_pstate_enabled(void);
+
+/* AMD P-States stuff **************************/
+
 /*
  * CPUID functions returning a single datum
  */
@@ -168,6 +175,9 @@ static inline int cpufreq_has_boost_support(unsigned int cpu, int *support,
 					    int *active, int * states)
 { return -1; }
 
+static inline bool cpupower_amd_pstate_enabled(void)
+{ return false; }
+
 /* cpuid and cpuinfo helpers  **************************/
 
 static inline unsigned int cpuid_eax(unsigned int op) { return 0; };
diff --git a/tools/power/cpupower/utils/helpers/misc.c b/tools/power/cpupower/utils/helpers/misc.c
index fc6e34511721..0c483cdefcc2 100644
--- a/tools/power/cpupower/utils/helpers/misc.c
+++ b/tools/power/cpupower/utils/helpers/misc.c
@@ -3,9 +3,11 @@
 #include <stdio.h>
 #include <errno.h>
 #include <stdlib.h>
+#include <string.h>
 
 #include "helpers/helpers.h"
 #include "helpers/sysfs.h"
+#include "cpufreq.h"
 
 #if defined(__i386__) || defined(__x86_64__)
 
@@ -83,6 +85,22 @@ int cpupower_intel_set_perf_bias(unsigned int cpu, unsigned int val)
 	return 0;
 }
 
+bool cpupower_amd_pstate_enabled(void)
+{
+	char *driver = cpufreq_get_driver(0);
+	bool ret = false;
+
+	if (!driver)
+		return ret;
+
+	if (!strcmp(driver, "amd-pstate"))
+		ret = true;
+
+	cpufreq_put_driver(driver);
+
+	return ret;
+}
+
 #endif /* #if defined(__i386__) || defined(__x86_64__) */
 
 /* get_cpustate
-- 
2.25.1