[PATCH 3/3] selftests: cpufreq: Add amd_pstate_testmod kernel module for testing

[Meng Li]

Add amd_pstate_testmod module, which is conceptually out-of-tree module and
provides ways for selftests/cpufreq amd pstate driver to test various
kernel module-related functionality. This module will be expected by some
of selftests to be present and loaded.

Signed-off-by: Meng Li <li.meng@xxxxxxx>
---
 .../cpufreq/amd_pstate_testmod/Makefile       |  20 ++
 .../amd_pstate_testmod/amd_pstate_testmod.c   | 302 ++++++++++++++++++
 2 files changed, 322 insertions(+)
 create mode 100644 tools/testing/selftests/cpufreq/amd_pstate_testmod/Makefile
 create mode 100644 tools/testing/selftests/cpufreq/amd_pstate_testmod/amd_pstate_testmod.c

diff --git a/tools/testing/selftests/cpufreq/amd_pstate_testmod/Makefile b/tools/testing/selftests/cpufreq/amd_pstate_testmod/Makefile
new file mode 100644
index 000000000000..8a5596cb2c18
--- /dev/null
+++ b/tools/testing/selftests/cpufreq/amd_pstate_testmod/Makefile
@@ -0,0 +1,20 @@
+AMD_PSTATE_TESTMOD_DIR := $(realpath $(dir $(abspath $(lastword $(MAKEFILE_LIST)))))
+KDIR ?= $(abspath $(AMD_PSATE_TESTMOD_DIR)/../../../../..)
+
+ifeq ($(V),1)
+Q =
+else
+Q = @
+endif
+
+MODULES = amd_pstate_testmod.ko
+
+obj-m += amd_pstate_testmod.o
+CFLAGS_amd_pstate_testmod.o = -I$(src)
+
+all:
+	+$(Q)make -C $(KDIR) M=$(AMD_PSTATE_TESTMOD_DIR) modules
+
+clean:
+	+$(Q)make -C $(KDIR) M=$(AMD_PSTATE_TESTMOD_DIR) clean
+
diff --git a/tools/testing/selftests/cpufreq/amd_pstate_testmod/amd_pstate_testmod.c b/tools/testing/selftests/cpufreq/amd_pstate_testmod/amd_pstate_testmod.c
new file mode 100644
index 000000000000..a892cecf19da
--- /dev/null
+++ b/tools/testing/selftests/cpufreq/amd_pstate_testmod/amd_pstate_testmod.c
@@ -0,0 +1,302 @@
+// SPDX-License-Identifier: GPL-1.0-or-later
+/*
+ * AMD Processor P-state Frequency Driver Unit Test
+ *
+ * Copyright (C) 2022 Advanced Micro Devices, Inc. All Rights Reserved.
+ *
+ * Author: Meng Li <li.meng@xxxxxxx>
+ *
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include "../../kselftest_module.h"
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/fs.h>
+#include <linux/amd-pstate.h>
+
+#include <acpi/cppc_acpi.h>
+
+/*
+ * Abbreviations:
+ * aput: used as a shortform for AMD P-State unit test.
+ * It helps to keep variable names smaller, simpler
+*/
+
+KSTM_MODULE_GLOBALS();
+
+/*
+ * Kernel module for testing the AMD P-State unit test
+ */
+enum aput_result {
+	APUT_RESULT_PASS,	//0
+	APUT_RESULT_FAIL,	//
+	MAX_APUT_RESULT,
+};
+
+struct aput_struct {
+	const char *name;
+	void (*func)(u32 index);
+	enum aput_result result;
+};
+
+static void aput_x86_vendor(u32 index);
+static void aput_acpi_cpc(u32 index);
+static void aput_modprobed_driver(u32 index);
+static void aput_capability_check(u32 index);
+static void aput_enable(u32 index);
+static void aput_init_perf(u32 index);
+static void aput_support_boost(u32 index);
+
+static struct aput_struct aput_cases[] = {
+	{"x86_vendor",          aput_x86_vendor          },
+	{"acpi_cpc_valid",      aput_acpi_cpc            },
+	{"modprobed_driver",    aput_modprobed_driver    },
+	{"capability_check",    aput_capability_check    },
+	{"enable",              aput_enable              },
+	{"init_perf",           aput_init_perf           },
+	{"support_boost",       aput_support_boost       }
+};
+
+static bool get_shared_mem(void)
+{
+	bool result = false;
+	char buf[5] = {0};
+	struct file *filp = NULL;
+	loff_t pos = 0;
+	ssize_t ret;
+
+	filp = filp_open("/sys/module/amd_pstate/parameters/shared_mem", FMODE_PREAD, 0);
+	if (IS_ERR(filp))
+	{
+		pr_err("%s Open param file fail! \n", __func__);
+	}
+	else
+	{
+		ret = kernel_read(filp, &buf, sizeof(buf), &pos);
+		if (ret < 0)
+		{
+			pr_err("%s ret=%ld unable to read from param file! \n", __func__, ret);
+		}
+		filp_close(filp, NULL);
+	}
+
+	if ('Y' == *buf)
+	{
+		result = true;
+	}
+
+	return (result);
+}
+
+static void aput_x86_vendor(u32 index)
+{
+	if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD)
+	{
+		aput_cases[index].result = APUT_RESULT_PASS;
+	}
+	else
+	{
+		aput_cases[index].result = APUT_RESULT_FAIL;
+	}
+}
+
+static void aput_acpi_cpc(u32 index)
+{
+	if (acpi_cpc_valid())
+	{
+		aput_cases[index].result = APUT_RESULT_PASS;
+	}
+	else
+	{
+		aput_cases[index].result = APUT_RESULT_FAIL;
+	}
+}
+
+static void aput_modprobed_driver(u32 index)
+{
+	if (cpufreq_get_current_driver())
+	{
+		aput_cases[index].result = APUT_RESULT_PASS;
+	}
+	else
+	{
+		aput_cases[index].result = APUT_RESULT_FAIL;
+	}
+}
+
+static void aput_capability_check(u32 index)
+{
+	if (boot_cpu_has(X86_FEATURE_CPPC))
+	{
+		aput_cases[index].result = APUT_RESULT_PASS;
+	}
+	else
+	{
+		//shared memory
+		if (get_shared_mem())
+		{
+			aput_cases[index].result = APUT_RESULT_PASS;
+		}
+		else
+		{
+			aput_cases[index].result = APUT_RESULT_FAIL;
+		}
+	}
+}
+
+static void aput_pstate_enable(u32 index)
+{
+	int ret = 0;
+	u64 cppc_enable = 0;
+
+	ret = rdmsrl_safe(MSR_AMD_CPPC_ENABLE, &cppc_enable);
+	if (ret)
+	{
+		aput_cases[index].result = APUT_RESULT_FAIL;
+		pr_err("%s rdmsrl_safe MSR_AMD_CPPC_ENABLE ret=%d is error! \n", __func__, ret);
+		return;
+	}
+	if (cppc_enable)
+	{
+		aput_cases[index].result = APUT_RESULT_PASS;
+	}
+	else
+	{
+		aput_cases[index].result = APUT_RESULT_FAIL;
+	}
+}
+
+static void aput_enable(u32 index)
+{
+	if (get_shared_mem())
+	{
+		//not check
+		aput_cases[index].result = APUT_RESULT_PASS;
+	}
+	else
+	{
+		aput_pstate_enable(index);
+	}
+}
+
+static void aput_init_perf(u32 index)
+{
+	int cpu = 0, ret = 0;
+	u32 highest_perf = 0, nominal_perf = 0, lowest_nonlinear_perf = 0, lowest_perf = 0;
+	u64 cap1 = 0;
+	struct cppc_perf_caps cppc_perf;
+	struct cpufreq_policy *policy = NULL;
+        struct amd_cpudata *cpudata = NULL;
+
+	//get perf
+	highest_perf = amd_get_highest_perf();
+
+	for_each_possible_cpu(cpu)
+	{
+		//get amd cpudata
+		policy = cpufreq_cpu_get(cpu);
+		if (!policy)
+			break;
+		cpudata = policy->driver_data;
+
+		if (get_shared_mem())
+		{
+			ret = cppc_get_perf_caps(cpu, &cppc_perf);
+			if (ret)
+			{
+				aput_cases[index].result = APUT_RESULT_FAIL;
+				pr_err("%s cppc_get_perf_caps ret=%d is error! \n", __func__, ret);
+				return;
+			}
+
+			nominal_perf = cppc_perf.nominal_perf;
+			lowest_nonlinear_perf = cppc_perf.lowest_nonlinear_perf;
+			lowest_perf = cppc_perf.lowest_perf;
+		}
+		else
+		{
+			ret = rdmsrl_safe_on_cpu(cpu, MSR_AMD_CPPC_CAP1, &cap1);
+			if (ret)
+			{
+				aput_cases[index].result = APUT_RESULT_FAIL;
+				pr_err("%s rdmsrl_safe_on_cpu MSR_AMD_CPPC_CAP1 ret=%d is error! \n", __func__, ret);
+				return;
+			}
+
+			//get perf from MSR
+			nominal_perf = AMD_CPPC_NOMINAL_PERF(cap1);
+			lowest_nonlinear_perf = AMD_CPPC_LOWNONLIN_PERF(cap1);
+			lowest_perf = AMD_CPPC_LOWEST_PERF(cap1);
+		}
+
+		//check highest_perf,nominal_perf,lowest_nonlinear_perf
+		if ((highest_perf != READ_ONCE(cpudata->highest_perf)) ||
+			(nominal_perf != READ_ONCE(cpudata->nominal_perf)) ||
+			(lowest_nonlinear_perf != READ_ONCE(cpudata->lowest_nonlinear_perf)) ||
+			(lowest_perf != READ_ONCE(cpudata->lowest_perf)))
+		{
+			aput_cases[index].result = APUT_RESULT_FAIL;
+			pr_err("%s cpu%d highest_perf=%d %d nominal_perf=%d %d lowest_nonlinear_perf=%d %d lowest_perf=%d %d are not equal! \n",
+				__func__, cpu, highest_perf, cpudata->highest_perf,
+				nominal_perf, cpudata->nominal_perf,
+				lowest_nonlinear_perf, cpudata->lowest_nonlinear_perf,
+				lowest_perf, cpudata->lowest_perf);
+			return;
+		}
+	}
+
+	aput_cases[index].result = APUT_RESULT_PASS;
+}
+
+static void aput_support_boost(u32 index)
+{
+	int cpu = 0;
+	struct cpufreq_policy *policy = NULL;
+        struct amd_cpudata *cpudata = NULL;
+
+	for_each_possible_cpu(cpu)
+	{
+		//get amd cpudata
+		policy = cpufreq_cpu_get(cpu);
+		if (!policy)
+			break;
+		cpudata = policy->driver_data;
+
+		if (READ_ONCE(cpudata->boost_supported))
+		{
+			aput_cases[index].result = APUT_RESULT_PASS;
+		}
+		else
+		{
+			aput_cases[index].result = APUT_RESULT_FAIL;
+			break;
+		}
+	}
+}
+
+static void aput_do_test_case(void)
+{
+	u32 i=0, arr_size = ARRAY_SIZE(aput_cases);
+
+	for (i = 0; i < arr_size; i++)
+	{
+		pr_info("****** Begin %-5d\t %-20s\t ******\n", i+1, aput_cases[i].name);
+		aput_cases[i].func(i);
+		KSTM_CHECK_ZERO(aput_cases[i].result);
+		pr_info("****** End   %-5d\t %-20s\t ******\n", i+1, aput_cases[i].name);
+	}
+}
+
+static void __init selftest(void)
+{
+	aput_do_test_case();
+}
+
+KSTM_MODULE_LOADERS(amd_pstate_testmod);
+MODULE_AUTHOR("Meng Li <li.meng@xxxxxxx>");
+MODULE_DESCRIPTION("Unit test for AMD P-state driver");
+MODULE_LICENSE("GPL");
-- 
2.25.1