1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * AMD Processor P-state Frequency Driver Unit Test
  4 *
  5 * Copyright (C) 2022 Advanced Micro Devices, Inc. All Rights Reserved.
  6 *
  7 * Author: Meng Li <li.meng@amd.com>
  8 *
  9 * The AMD P-State Unit Test is a test module for testing the amd-pstate
 10 * driver. 1) It can help all users to verify their processor support
 11 * (SBIOS/Firmware or Hardware). 2) Kernel can have a basic function
 12 * test to avoid the kernel regression during the update. 3) We can
 13 * introduce more functional or performance tests to align the result
 14 * together, it will benefit power and performance scale optimization.
 15 *
 16 * This driver implements basic framework with plans to enhance it with
 17 * additional test cases to improve the depth and coverage of the test.
 18 *
 19 * See Documentation/admin-guide/pm/amd-pstate.rst Unit Tests for
 20 * amd-pstate to get more detail.
 21 */
 22
 23#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 24
 25#include <linux/kernel.h>
 26#include <linux/module.h>
 27#include <linux/moduleparam.h>
 28#include <linux/fs.h>
 29#include <linux/amd-pstate.h>
 30
 31#include <acpi/cppc_acpi.h>
 32
 33/*
 34 * Abbreviations:
 35 * amd_pstate_ut: used as a shortform for AMD P-State unit test.
 36 * It helps to keep variable names smaller, simpler
 37 */
 38enum amd_pstate_ut_result {
 39	AMD_PSTATE_UT_RESULT_PASS,
 40	AMD_PSTATE_UT_RESULT_FAIL,
 41};
 42
 43struct amd_pstate_ut_struct {
 44	const char *name;
 45	void (*func)(u32 index);
 46	enum amd_pstate_ut_result result;
 47};
 48
 49/*
 50 * Kernel module for testing the AMD P-State unit test
 51 */
 52static void amd_pstate_ut_acpi_cpc_valid(u32 index);
 53static void amd_pstate_ut_check_enabled(u32 index);
 54static void amd_pstate_ut_check_perf(u32 index);
 55static void amd_pstate_ut_check_freq(u32 index);
 56
 57static struct amd_pstate_ut_struct amd_pstate_ut_cases[] = {
 58	{"amd_pstate_ut_acpi_cpc_valid",   amd_pstate_ut_acpi_cpc_valid   },
 59	{"amd_pstate_ut_check_enabled",    amd_pstate_ut_check_enabled    },
 60	{"amd_pstate_ut_check_perf",       amd_pstate_ut_check_perf       },
 61	{"amd_pstate_ut_check_freq",       amd_pstate_ut_check_freq       }
 62};
 63
 64static bool get_shared_mem(void)
 65{
 66	bool result = false;
 67	char path[] = "/sys/module/amd_pstate/parameters/shared_mem";
 68	char buf[5] = {0};
 69	struct file *filp = NULL;
 70	loff_t pos = 0;
 71	ssize_t ret;
 72
 73	if (!boot_cpu_has(X86_FEATURE_CPPC)) {
 74		filp = filp_open(path, O_RDONLY, 0);
 75		if (IS_ERR(filp))
 76			pr_err("%s unable to open %s file!\n", __func__, path);
 77		else {
 78			ret = kernel_read(filp, &buf, sizeof(buf), &pos);
 79			if (ret < 0)
 80				pr_err("%s read %s file fail ret=%ld!\n",
 81					__func__, path, (long)ret);
 82			filp_close(filp, NULL);
 83		}
 84
 85		if ('Y' == *buf)
 86			result = true;
 87	}
 88
 89	return result;
 90}
 91
 92/*
 93 * check the _CPC object is present in SBIOS.
 94 */
 95static void amd_pstate_ut_acpi_cpc_valid(u32 index)
 96{
 97	if (acpi_cpc_valid())
 98		amd_pstate_ut_cases[index].result = AMD_PSTATE_UT_RESULT_PASS;
 99	else {
100		amd_pstate_ut_cases[index].result = AMD_PSTATE_UT_RESULT_FAIL;
101		pr_err("%s the _CPC object is not present in SBIOS!\n", __func__);
102	}
103}
104
105static void amd_pstate_ut_pstate_enable(u32 index)
106{
107	int ret = 0;
108	u64 cppc_enable = 0;
109
110	ret = rdmsrl_safe(MSR_AMD_CPPC_ENABLE, &cppc_enable);
111	if (ret) {
112		amd_pstate_ut_cases[index].result = AMD_PSTATE_UT_RESULT_FAIL;
113		pr_err("%s rdmsrl_safe MSR_AMD_CPPC_ENABLE ret=%d error!\n", __func__, ret);
114		return;
115	}
116	if (cppc_enable)
117		amd_pstate_ut_cases[index].result = AMD_PSTATE_UT_RESULT_PASS;
118	else {
119		amd_pstate_ut_cases[index].result = AMD_PSTATE_UT_RESULT_FAIL;
120		pr_err("%s amd pstate must be enabled!\n", __func__);
121	}
122}
123
124/*
125 * check if amd pstate is enabled
126 */
127static void amd_pstate_ut_check_enabled(u32 index)
128{
129	if (get_shared_mem())
130		amd_pstate_ut_cases[index].result = AMD_PSTATE_UT_RESULT_PASS;
131	else
132		amd_pstate_ut_pstate_enable(index);
133}
134
135/*
136 * check if performance values are reasonable.
137 * highest_perf >= nominal_perf > lowest_nonlinear_perf > lowest_perf > 0
138 */
139static void amd_pstate_ut_check_perf(u32 index)
140{
141	int cpu = 0, ret = 0;
142	u32 highest_perf = 0, nominal_perf = 0, lowest_nonlinear_perf = 0, lowest_perf = 0;
143	u64 cap1 = 0;
144	struct cppc_perf_caps cppc_perf;
145	struct cpufreq_policy *policy = NULL;
146	struct amd_cpudata *cpudata = NULL;
147
148	highest_perf = amd_get_highest_perf();
149
150	for_each_possible_cpu(cpu) {
151		policy = cpufreq_cpu_get(cpu);
152		if (!policy)
153			break;
154		cpudata = policy->driver_data;
155
156		if (get_shared_mem()) {
157			ret = cppc_get_perf_caps(cpu, &cppc_perf);
158			if (ret) {
159				amd_pstate_ut_cases[index].result = AMD_PSTATE_UT_RESULT_FAIL;
160				pr_err("%s cppc_get_perf_caps ret=%d error!\n", __func__, ret);
161				return;
162			}
163
164			nominal_perf = cppc_perf.nominal_perf;
165			lowest_nonlinear_perf = cppc_perf.lowest_nonlinear_perf;
166			lowest_perf = cppc_perf.lowest_perf;
167		} else {
168			ret = rdmsrl_safe_on_cpu(cpu, MSR_AMD_CPPC_CAP1, &cap1);
169			if (ret) {
170				amd_pstate_ut_cases[index].result = AMD_PSTATE_UT_RESULT_FAIL;
171				pr_err("%s read CPPC_CAP1 ret=%d error!\n", __func__, ret);
172				return;
173			}
174
175			nominal_perf = AMD_CPPC_NOMINAL_PERF(cap1);
176			lowest_nonlinear_perf = AMD_CPPC_LOWNONLIN_PERF(cap1);
177			lowest_perf = AMD_CPPC_LOWEST_PERF(cap1);
178		}
179
180		if ((highest_perf != READ_ONCE(cpudata->highest_perf)) ||
181			(nominal_perf != READ_ONCE(cpudata->nominal_perf)) ||
182			(lowest_nonlinear_perf != READ_ONCE(cpudata->lowest_nonlinear_perf)) ||
183			(lowest_perf != READ_ONCE(cpudata->lowest_perf))) {
184			amd_pstate_ut_cases[index].result = AMD_PSTATE_UT_RESULT_FAIL;
185			pr_err("%s cpu%d highest=%d %d nominal=%d %d lowest_nonlinear=%d %d lowest=%d %d, they should be equal!\n",
186				__func__, cpu, highest_perf, cpudata->highest_perf,
187				nominal_perf, cpudata->nominal_perf,
188				lowest_nonlinear_perf, cpudata->lowest_nonlinear_perf,
189				lowest_perf, cpudata->lowest_perf);
190			return;
191		}
192
193		if (!((highest_perf >= nominal_perf) &&
194			(nominal_perf > lowest_nonlinear_perf) &&
195			(lowest_nonlinear_perf > lowest_perf) &&
196			(lowest_perf > 0))) {
197			amd_pstate_ut_cases[index].result = AMD_PSTATE_UT_RESULT_FAIL;
198			pr_err("%s cpu%d highest=%d >= nominal=%d > lowest_nonlinear=%d > lowest=%d > 0, the formula is incorrect!\n",
199				__func__, cpu, highest_perf, nominal_perf,
200				lowest_nonlinear_perf, lowest_perf);
201			return;
202		}
203	}
204
205	amd_pstate_ut_cases[index].result = AMD_PSTATE_UT_RESULT_PASS;
206}
207
208/*
209 * Check if frequency values are reasonable.
210 * max_freq >= nominal_freq > lowest_nonlinear_freq > min_freq > 0
211 * check max freq when set support boost mode.
212 */
213static void amd_pstate_ut_check_freq(u32 index)
214{
215	int cpu = 0;
216	struct cpufreq_policy *policy = NULL;
217	struct amd_cpudata *cpudata = NULL;
218
219	for_each_possible_cpu(cpu) {
220		policy = cpufreq_cpu_get(cpu);
221		if (!policy)
222			break;
223		cpudata = policy->driver_data;
224
225		if (!((cpudata->max_freq >= cpudata->nominal_freq) &&
226			(cpudata->nominal_freq > cpudata->lowest_nonlinear_freq) &&
227			(cpudata->lowest_nonlinear_freq > cpudata->min_freq) &&
228			(cpudata->min_freq > 0))) {
229			amd_pstate_ut_cases[index].result = AMD_PSTATE_UT_RESULT_FAIL;
230			pr_err("%s cpu%d max=%d >= nominal=%d > lowest_nonlinear=%d > min=%d > 0, the formula is incorrect!\n",
231				__func__, cpu, cpudata->max_freq, cpudata->nominal_freq,
232				cpudata->lowest_nonlinear_freq, cpudata->min_freq);
233			return;
234		}
235
236		if (cpudata->min_freq != policy->min) {
237			amd_pstate_ut_cases[index].result = AMD_PSTATE_UT_RESULT_FAIL;
238			pr_err("%s cpu%d cpudata_min_freq=%d policy_min=%d, they should be equal!\n",
239				__func__, cpu, cpudata->min_freq, policy->min);
240			return;
241		}
242
243		if (cpudata->boost_supported) {
244			if ((policy->max == cpudata->max_freq) ||
245					(policy->max == cpudata->nominal_freq))
246				amd_pstate_ut_cases[index].result = AMD_PSTATE_UT_RESULT_PASS;
247			else {
248				amd_pstate_ut_cases[index].result = AMD_PSTATE_UT_RESULT_FAIL;
249				pr_err("%s cpu%d policy_max=%d should be equal cpu_max=%d or cpu_nominal=%d !\n",
250					__func__, cpu, policy->max, cpudata->max_freq,
251					cpudata->nominal_freq);
252				return;
253			}
254		} else {
255			amd_pstate_ut_cases[index].result = AMD_PSTATE_UT_RESULT_FAIL;
256			pr_err("%s cpu%d must support boost!\n", __func__, cpu);
257			return;
258		}
259	}
260
261	amd_pstate_ut_cases[index].result = AMD_PSTATE_UT_RESULT_PASS;
262}
263
264static int __init amd_pstate_ut_init(void)
265{
266	u32 i = 0, arr_size = ARRAY_SIZE(amd_pstate_ut_cases);
267
268	for (i = 0; i < arr_size; i++) {
269		amd_pstate_ut_cases[i].func(i);
270		switch (amd_pstate_ut_cases[i].result) {
271		case AMD_PSTATE_UT_RESULT_PASS:
272			pr_info("%-4d %-20s\t success!\n", i+1, amd_pstate_ut_cases[i].name);
273			break;
274		case AMD_PSTATE_UT_RESULT_FAIL:
275		default:
276			pr_info("%-4d %-20s\t fail!\n", i+1, amd_pstate_ut_cases[i].name);
277			break;
278		}
279	}
280
281	return 0;
282}
283
284static void __exit amd_pstate_ut_exit(void)
285{
286}
287
288module_init(amd_pstate_ut_init);
289module_exit(amd_pstate_ut_exit);
290
291MODULE_AUTHOR("Meng Li <li.meng@amd.com>");
292MODULE_DESCRIPTION("AMD P-state driver Test module");
293MODULE_LICENSE("GPL");