amd-pstate-ut: Reset amd-pstate driver mode after running selftests

In amd-pstate-ut, one of the basic test is to switch between all
possible mode combinations. After running this test the mode of the
amd-pstate driver is active mode. Store and reset the mode to its original
state.

Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Signed-off-by: Swapnil Sapkal <swapnil.sapkal@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Link: https://lore.kernel.org/r/20250430064206.7402-1-swapnil.sapkal@amd.com
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>

Author: SSapkal

drivers/cpufreq/amd-pstate-ut.c

@@ -242,6 +242,8 @@ static int amd_pstate_set_mode(enum amd_pstate_mode mode)
 static int amd_pstate_ut_check_driver(u32 index)
 {
 	enum amd_pstate_mode mode1, mode2 = AMD_PSTATE_DISABLE;
+	enum amd_pstate_mode orig_mode = amd_pstate_get_status();
+	int ret;
 
 	for (mode1 = AMD_PSTATE_DISABLE; mode1 < AMD_PSTATE_MAX; mode1++) {
 		int ret = amd_pstate_set_mode(mode1);
@@ -251,16 +253,19 @@ static int amd_pstate_ut_check_driver(u32 index)
 			if (mode1 == mode2)
 				continue;
 			ret = amd_pstate_set_mode(mode2);
-			if (ret) {
-				pr_err("%s: failed to update status for %s->%s\n", __func__,
-					amd_pstate_get_mode_string(mode1),
-					amd_pstate_get_mode_string(mode2));
-				return ret;
-			}
+			if (ret)
+				goto out;
 		}
 	}
 
-	return 0;
+out:
+	if (ret)
+		pr_warn("%s: failed to update status for %s->%s: %d\n", __func__,
+			amd_pstate_get_mode_string(mode1),
+			amd_pstate_get_mode_string(mode2), ret);
+
+	amd_pstate_set_mode(orig_mode);
+	return ret;
 }
 
 static int __init amd_pstate_ut_init(void)

drivers/cpufreq/amd-pstate.c

@@ -1332,6 +1332,12 @@ static ssize_t amd_pstate_show_status(char *buf)
 	return sysfs_emit(buf, "%s\n", amd_pstate_mode_string[cppc_state]);
 }
 
+int amd_pstate_get_status(void)
+{
+	return cppc_state;
+}
+EXPORT_SYMBOL_GPL(amd_pstate_get_status);
+
 int amd_pstate_update_status(const char *buf, size_t size)
 {
 	int mode_idx;

drivers/cpufreq/amd-pstate.h

@@ -121,6 +121,7 @@ enum amd_pstate_mode {
 	AMD_PSTATE_MAX,
 };
 const char *amd_pstate_get_mode_string(enum amd_pstate_mode mode);
+int amd_pstate_get_status(void);
 int amd_pstate_update_status(const char *buf, size_t size);
 
 #endif /* _LINUX_AMD_PSTATE_H */