cpupower: Add support for amd_pstate mode change

amd_pstate supports changing of its mode dynamically via `status` sysfs
file. Add the same capability in cpupower. To change the mode to active
mode use below command:

cpupower set --amd-pstate-mode active

Acked-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Wyes Karny <wyes.karny@amd.com>
Tested-by: Perry Yuan <Perry.Yuan@amd.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

Author: wkarny

tools/power/cpupower/utils/cpupower-set.c

@@ -19,6 +19,7 @@
 static struct option set_opts[] = {
 	{"perf-bias", required_argument, NULL, 'b'},
 	{"epp", required_argument, NULL, 'e'},
+	{"amd-pstate-mode", required_argument, NULL, 'm'},
 	{ },
 };
 
@@ -39,12 +40,13 @@ int cmd_set(int argc, char **argv)
 		struct {
 			int perf_bias:1;
 			int epp:1;
+			int mode:1;
 		};
 		int params;
 	} params;
 	int perf_bias = 0;
 	int ret = 0;
-	char epp[30];
+	char epp[30], mode[20];
 
 	ret = uname(&uts);
 	if (!ret && (!strcmp(uts.machine, "ppc64le") ||
@@ -58,7 +60,7 @@ int cmd_set(int argc, char **argv)
 
 	params.params = 0;
 	/* parameter parsing */
-	while ((ret = getopt_long(argc, argv, "b:e:",
+	while ((ret = getopt_long(argc, argv, "b:e:m:",
 						set_opts, NULL)) != -1) {
 		switch (ret) {
 		case 'b':
@@ -81,6 +83,17 @@ int cmd_set(int argc, char **argv)
 			}
 			params.epp = 1;
 			break;
+		case 'm':
+			if (cpupower_cpu_info.vendor != X86_VENDOR_AMD)
+				print_wrong_arg_exit();
+			if (params.mode)
+				print_wrong_arg_exit();
+			if (sscanf(optarg, "%19s", mode) != 1) {
+				print_wrong_arg_exit();
+				return -EINVAL;
+			}
+			params.mode = 1;
+			break;
 		default:
 			print_wrong_arg_exit();
 		}
@@ -89,6 +102,12 @@ int cmd_set(int argc, char **argv)
 	if (!params.params)
 		print_wrong_arg_exit();
 
+	if (params.mode) {
+		ret = cpupower_set_amd_pstate_mode(mode);
+		if (ret)
+			fprintf(stderr, "Error setting mode\n");
+	}
+
 	/* Default is: set all CPUs */
 	if (bitmask_isallclear(cpus_chosen))
 		bitmask_setall(cpus_chosen);
@@ -123,6 +142,7 @@ int cmd_set(int argc, char **argv)
 				break;
 			}
 		}
+
 	}
 	return ret;
 }

tools/power/cpupower/utils/helpers/helpers.h

@@ -117,6 +117,7 @@ extern int cpupower_intel_get_perf_bias(unsigned int cpu);
 extern unsigned long long msr_intel_get_turbo_ratio(unsigned int cpu);
 
 extern int cpupower_set_epp(unsigned int cpu, char *epp);
+extern int cpupower_set_amd_pstate_mode(char *mode);
 
 /* Read/Write msr ****************************/
 
@@ -177,6 +178,8 @@ static inline unsigned long long msr_intel_get_turbo_ratio(unsigned int cpu)
 
 static inline int cpupower_set_epp(unsigned int cpu, char *epp)
 { return -1; };
+static inline int cpupower_set_amd_pstate_mode(char *mode)
+{ return -1; };
 
 /* Read/Write msr ****************************/
 

tools/power/cpupower/utils/helpers/misc.c

@@ -106,6 +106,24 @@ int cpupower_set_epp(unsigned int cpu, char *epp)
 	return 0;
 }
 
+int cpupower_set_amd_pstate_mode(char *mode)
+{
+	char path[SYSFS_PATH_MAX];
+	char linebuf[20] = {};
+
+	snprintf(path, sizeof(path), PATH_TO_CPU "amd_pstate/status");
+
+	if (!is_valid_path(path))
+		return -1;
+
+	snprintf(linebuf, sizeof(linebuf), "%s\n", mode);
+
+	if (cpupower_write_sysfs(path, linebuf, 20) <= 0)
+		return -1;
+
+	return 0;
+}
+
 bool cpupower_amd_pstate_enabled(void)
 {
 	char *driver = cpufreq_get_driver(0);