linux-kernel - [PATCH 5/5] cpufreq/amd-pstate-ut: Add a unit test for raw EPP

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Message-ID: <20250215005448.1216646-6-superm1@kernel.org>
Date: Fri, 14 Feb 2025 18:54:48 -0600
From: Mario Limonciello <superm1@...nel.org>
To: "Gautham R . Shenoy" <gautham.shenoy@....com>,
	Perry Yuan <perry.yuan@....com>
Cc: Dhananjay Ugwekar <Dhananjay.Ugwekar@....com>,
	linux-kernel@...r.kernel.org (open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)),
	linux-pm@...r.kernel.org (open list:CPU FREQUENCY SCALING FRAMEWORK),
	Mario Limonciello <mario.limonciello@....com>
Subject: [PATCH 5/5] cpufreq/amd-pstate-ut: Add a unit test for raw EPP

From: Mario Limonciello <mario.limonciello@....com>

Ensure that all supported raw EPP values work properly.

Signed-off-by: Mario Limonciello <mario.limonciello@....com>
---
 drivers/cpufreq/amd-pstate-ut.c | 58 +++++++++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)

diff --git a/drivers/cpufreq/amd-pstate-ut.c b/drivers/cpufreq/amd-pstate-ut.c
index 067e9e325102e..b5bf0c37d8037 100644
--- a/drivers/cpufreq/amd-pstate-ut.c
+++ b/drivers/cpufreq/amd-pstate-ut.c
@@ -25,6 +25,7 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
+#include <linux/mm.h>
 #include <linux/fs.h>
 #include <linux/cleanup.h>
 
@@ -32,6 +33,7 @@
 
 #include "amd-pstate.h"
 
+DEFINE_FREE(free_page, void *, if (_T) free_page((unsigned long)_T))
 
 struct amd_pstate_ut_struct {
 	const char *name;
@@ -45,6 +47,7 @@ static int amd_pstate_ut_acpi_cpc_valid(u32 index);
 static int amd_pstate_ut_check_enabled(u32 index);
 static int amd_pstate_ut_check_perf(u32 index);
 static int amd_pstate_ut_check_freq(u32 index);
+static int amd_pstate_ut_epp(u32 index);
 static int amd_pstate_ut_check_driver(u32 index);
 
 static struct amd_pstate_ut_struct amd_pstate_ut_cases[] = {
@@ -52,6 +55,7 @@ static struct amd_pstate_ut_struct amd_pstate_ut_cases[] = {
 	{"amd_pstate_ut_check_enabled",    amd_pstate_ut_check_enabled    },
 	{"amd_pstate_ut_check_perf",       amd_pstate_ut_check_perf       },
 	{"amd_pstate_ut_check_freq",       amd_pstate_ut_check_freq       },
+	{"amd_pstate_ut_epp",              amd_pstate_ut_epp              },
 	{"amd_pstate_ut_check_driver",	   amd_pstate_ut_check_driver     }
 };
 
@@ -238,6 +242,60 @@ static int amd_pstate_set_mode(enum amd_pstate_mode mode)
 	return amd_pstate_update_status(mode_str, strlen(mode_str));
 }
 
+static int amd_pstate_ut_epp(u32 index)
+{
+	struct cpufreq_policy *policy __free(put_cpufreq_policy) = NULL;
+	void *buf __free(free_page) = NULL;
+	struct amd_cpudata *cpudata;
+	int ret, cpu = 0;
+	u16 epp;
+
+	policy = cpufreq_cpu_get(cpu);
+	if (!policy)
+		return -ENODEV;
+
+	cpudata = policy->driver_data;
+
+	/* disable dynamic EPP before running test */
+	if (cpudata->dynamic_epp) {
+		pr_debug("Dynamic EPP is enabled, disabling it\n");
+		amd_pstate_clear_dynamic_epp(policy);
+	}
+
+	buf = (void *)__get_free_page(GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	ret = amd_pstate_set_mode(AMD_PSTATE_ACTIVE);
+	if (ret)
+		return ret;
+
+	for (epp = 0; epp <= U8_MAX; epp++) {
+		u8 val;
+
+		/* write all EPP values */
+		memset(buf, 0, sizeof(buf));
+		snprintf(buf, PAGE_SIZE, "%d", epp);
+		ret = store_energy_performance_preference(policy, buf, sizeof(buf));
+		if (ret < 0)
+			return ret;
+
+		/* check if the EPP value reads back correctly for raw numbers */
+		memset(buf, 0, sizeof(buf));
+		ret = show_energy_performance_preference(policy, buf);
+		if (ret < 0)
+			return ret;
+		strreplace(buf, '\n', '\0');
+		ret = kstrtou8(buf, 0, &val);
+		if (!ret && epp != val) {
+			pr_err("Raw EPP value mismatch: %d != %d\n", epp, val);
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
 static int amd_pstate_ut_check_driver(u32 index)
 {
 	enum amd_pstate_mode mode1, mode2 = AMD_PSTATE_DISABLE;
-- 
2.43.0