linux/drivers/cpufreq/amd-pstate-ut.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * AMD Processor P-state Frequency Driver Unit Test
 *
 * Copyright (C) 2022 Advanced Micro Devices, Inc. All Rights Reserved.
 *
 * Author: Meng Li <[email protected]>
 *
 * The AMD P-State Unit Test is a test module for testing the amd-pstate
 * driver. 1) It can help all users to verify their processor support
 * (SBIOS/Firmware or Hardware). 2) Kernel can have a basic function
 * test to avoid the kernel regression during the update. 3) We can
 * introduce more functional or performance tests to align the result
 * together, it will benefit power and performance scale optimization.
 *
 * This driver implements basic framework with plans to enhance it with
 * additional test cases to improve the depth and coverage of the test.
 *
 * See Documentation/admin-guide/pm/amd-pstate.rst Unit Tests for
 * amd-pstate to get more detail.
 */

#define pr_fmt(fmt) …

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/fs.h>

#include <acpi/cppc_acpi.h>

#include "amd-pstate.h"

/*
 * Abbreviations:
 * amd_pstate_ut: used as a shortform for AMD P-State unit test.
 * It helps to keep variable names smaller, simpler
 */
enum amd_pstate_ut_result { … };

struct amd_pstate_ut_struct { … };

/*
 * Kernel module for testing the AMD P-State unit test
 */
static void amd_pstate_ut_acpi_cpc_valid(u32 index);
static void amd_pstate_ut_check_enabled(u32 index);
static void amd_pstate_ut_check_perf(u32 index);
static void amd_pstate_ut_check_freq(u32 index);

static struct amd_pstate_ut_struct amd_pstate_ut_cases[] = …;

static bool get_shared_mem(void)
{ … }

/*
 * check the _CPC object is present in SBIOS.
 */
static void amd_pstate_ut_acpi_cpc_valid(u32 index)
{ … }

static void amd_pstate_ut_pstate_enable(u32 index)
{ … }

/*
 * check if amd pstate is enabled
 */
static void amd_pstate_ut_check_enabled(u32 index)
{ … }

/*
 * check if performance values are reasonable.
 * highest_perf >= nominal_perf > lowest_nonlinear_perf > lowest_perf > 0
 */
static void amd_pstate_ut_check_perf(u32 index)
{ … }

/*
 * Check if frequency values are reasonable.
 * max_freq >= nominal_freq > lowest_nonlinear_freq > min_freq > 0
 * check max freq when set support boost mode.
 */
static void amd_pstate_ut_check_freq(u32 index)
{ … }

static int __init amd_pstate_ut_init(void)
{ … }

static void __exit amd_pstate_ut_exit(void)
{ … }

module_init(…) …;
module_exit(amd_pstate_ut_exit);

MODULE_AUTHOR(…) …;
MODULE_DESCRIPTION(…) …;
MODULE_LICENSE(…) …;