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  */
38 enum amd_pstate_ut_result {
39 	AMD_PSTATE_UT_RESULT_PASS,
40 	AMD_PSTATE_UT_RESULT_FAIL,
41 };
42 
43 struct 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  */
52 static void amd_pstate_ut_acpi_cpc_valid(u32 index);
53 static void amd_pstate_ut_check_enabled(u32 index);
54 static void amd_pstate_ut_check_perf(u32 index);
55 static void amd_pstate_ut_check_freq(u32 index);
56 
57 static 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 
64 static 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  */
95 static 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 
105 static 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  */
127 static 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  */
139 static 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  */
213 static 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 
264 static 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 
284 static void __exit amd_pstate_ut_exit(void)
285 {
286 }
287 
288 module_init(amd_pstate_ut_init);
289 module_exit(amd_pstate_ut_exit);
290 
291 MODULE_AUTHOR("Meng Li <li.meng@amd.com>");
292 MODULE_DESCRIPTION("AMD P-state driver Test module");
293 MODULE_LICENSE("GPL");
294