[RFC PATCH 6/6] cpufreq/amd-pstate-ut: Add unit test for "dynamic" EPP mode

[K Prateek Nayak]

Extend the EPP unit test to cover the "dynamic" epp mode. Since
"dynamic_epp" is no longer a system-wide toggle, remove the legacy
"dynamic_epp" bits from the unit test.

Signed-off-by: K Prateek Nayak <kprateek.nayak@xxxxxxx>
---
 drivers/cpufreq/amd-pstate-ut.c | 48 ++++++++++++++++++---------------
 drivers/cpufreq/amd-pstate.c    |  6 +++++
 drivers/cpufreq/amd-pstate.h    |  1 +
 3 files changed, 33 insertions(+), 22 deletions(-)

diff --git a/drivers/cpufreq/amd-pstate-ut.c b/drivers/cpufreq/amd-pstate-ut.c
index 735b29f76438..affe36218d73 100644
--- a/drivers/cpufreq/amd-pstate-ut.c
+++ b/drivers/cpufreq/amd-pstate-ut.c
@@ -275,6 +275,7 @@ static int amd_pstate_set_mode(enum amd_pstate_mode mode)
 static int amd_pstate_ut_epp(u32 index)
 {
 	static const char * const epp_strings[] = {
+		"dynamic",
 		"power",
 		"balance_power",
 		"balance_performance",
@@ -282,10 +283,10 @@ static int amd_pstate_ut_epp(u32 index)
 	};
 	char *buf __free(cleanup_page) = NULL;
 	struct cpufreq_policy *policy = NULL;
+	unsigned long orig_dynamic_epp = 0;
 	enum amd_pstate_mode orig_mode;
 	struct amd_cpudata *cpudata;
 	unsigned long orig_policy;
-	bool orig_dynamic_epp;
 	int ret, cpu = 0;
 	u16 epp;
 	int i;
@@ -294,9 +295,11 @@ static int amd_pstate_ut_epp(u32 index)
 	if (!policy)
 		return -ENODEV;
 
-	cpudata = policy->driver_data;
 	orig_mode = amd_pstate_get_status();
-	orig_dynamic_epp = cpudata->dynamic_epp;
+	if (policy->driver_data) {
+		cpudata = policy->driver_data;
+		orig_dynamic_epp = cpudata->dynamic_epp;
+	}
 
 	/* Drop reference before potential driver change. */
 	cpufreq_cpu_put(policy);
@@ -321,16 +324,6 @@ static int amd_pstate_ut_epp(u32 index)
 	orig_policy = cpudata->policy;
 	cpudata->policy = CPUFREQ_POLICY_POWERSAVE;
 
-	/*
-	 * Disable dynamic EPP before running test. If "orig_dynamic_epp" is
-	 * true, the  driver will do a redundant switch at the end and there
-	 * is no need for enabling it again at the end of the test.
-	 */
-	if (cpudata->dynamic_epp) {
-		pr_debug("Dynamic EPP is enabled, disabling it\n");
-		amd_pstate_clear_dynamic_epp(policy);
-	}
-
 	for (epp = 0; epp <= U8_MAX; epp++) {
 		u8 val;
 
@@ -355,7 +348,8 @@ static int amd_pstate_ut_epp(u32 index)
 		}
 	}
 
-	for (i = 0; i < ARRAY_SIZE(epp_strings); i++) {
+	/* If dynamic EPP is disabled via cmdline, start at index 1. */
+	for (i = amd_pstate_dynamic_epp_disabled(); i < ARRAY_SIZE(epp_strings); i++) {
 		memset(buf, 0, PAGE_SIZE);
 		snprintf(buf, PAGE_SIZE, "%s", epp_strings[i]);
 		ret = store_energy_performance_preference(policy, buf, strlen(buf));
@@ -367,6 +361,11 @@ static int amd_pstate_ut_epp(u32 index)
 		if (ret < 0)
 			goto out;
 		strreplace(buf, '\n', '\0');
+		/*
+		 * "dynamic" mode reports the EPP as "dynamic(profile:X)"
+		 * Trim at "(" and just compare tie the epp string.
+		 */
+		strreplace(buf, '(', '\0');
 
 		if (strcmp(buf, epp_strings[i])) {
 			pr_err("String EPP value mismatch: %s != %s\n", buf, epp_strings[i]);
@@ -380,18 +379,23 @@ static int amd_pstate_ut_epp(u32 index)
 out:
 	if (policy) {
 		cpudata->policy = orig_policy;
+		/*
+		 * If the driver had enabled dynamic_epp to brgin with,
+		 * restore it here before dropping policy reference.
+		 */
+		if (orig_dynamic_epp) {
+			int ret2;
+
+			ret2 = store_energy_performance_preference(policy,
+								  epp_strings[0],
+								  strlen(epp_strings[0]));
+			if (!ret && (ret2 < 0))
+				ret = ret2;
+		}
 		up_write(&policy->rwsem);
 		cpufreq_cpu_put(policy);
 	}
 
-	if (orig_dynamic_epp) {
-		int ret2;
-
-		ret2 = amd_pstate_set_mode(AMD_PSTATE_DISABLE);
-		if (!ret && ret2)
-			ret = ret2;
-	}
-
 	if (orig_mode != amd_pstate_get_status()) {
 		int ret2;
 
diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 44c03b0be219..e7f83482c8cb 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -1253,6 +1253,12 @@ static const struct platform_profile_ops amd_pstate_profile_ops = {
 	.profile_get = amd_pstate_profile_get,
 };
 
+int amd_pstate_dynamic_epp_disabled(void)
+{
+	return !dynamic_epp;
+}
+EXPORT_SYMBOL_FOR_PSTATE_UT(amd_pstate_dynamic_epp_disabled);
+
 void amd_pstate_clear_dynamic_epp(struct cpufreq_policy *policy)
 {
 	struct amd_cpudata *cpudata = policy->driver_data;
diff --git a/drivers/cpufreq/amd-pstate.h b/drivers/cpufreq/amd-pstate.h
index edd697a5e29f..bbde1d035071 100644
--- a/drivers/cpufreq/amd-pstate.h
+++ b/drivers/cpufreq/amd-pstate.h
@@ -160,6 +160,7 @@ ssize_t store_energy_performance_preference(struct cpufreq_policy *policy,
 				    const char *buf, size_t count);
 ssize_t show_energy_performance_preference(struct cpufreq_policy *policy, char *buf);
 void amd_pstate_clear_dynamic_epp(struct cpufreq_policy *policy);
+int amd_pstate_dynamic_epp_disabled(void);
 
 struct freq_attr;
 
-- 
2.34.1