1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * cppc.c: CPPC Interface for x86
4 * Copyright (c) 2016, Intel Corporation.
5 */
6
7 #include <acpi/cppc_acpi.h>
8 #include <asm/msr.h>
9 #include <asm/processor.h>
10 #include <asm/topology.h>
11
12 #define CPPC_HIGHEST_PERF_PERFORMANCE 196
13 #define CPPC_HIGHEST_PERF_PREFCORE 166
14
15 enum amd_pref_core {
16 AMD_PREF_CORE_UNKNOWN = 0,
17 AMD_PREF_CORE_SUPPORTED,
18 AMD_PREF_CORE_UNSUPPORTED,
19 };
20 static enum amd_pref_core amd_pref_core_detected;
21 static u64 boost_numerator;
22
23 /* Refer to drivers/acpi/cppc_acpi.c for the description of functions */
24
cpc_supported_by_cpu(void)25 bool cpc_supported_by_cpu(void)
26 {
27 switch (boot_cpu_data.x86_vendor) {
28 case X86_VENDOR_AMD:
29 case X86_VENDOR_HYGON:
30 if (boot_cpu_data.x86 == 0x19 && ((boot_cpu_data.x86_model <= 0x0f) ||
31 (boot_cpu_data.x86_model >= 0x20 && boot_cpu_data.x86_model <= 0x2f)))
32 return true;
33 else if (boot_cpu_data.x86 == 0x17 &&
34 boot_cpu_data.x86_model >= 0x30 && boot_cpu_data.x86_model <= 0x7f)
35 return true;
36 return boot_cpu_has(X86_FEATURE_CPPC);
37 }
38 return false;
39 }
40
cpc_ffh_supported(void)41 bool cpc_ffh_supported(void)
42 {
43 return true;
44 }
45
cpc_read_ffh(int cpunum,struct cpc_reg * reg,u64 * val)46 int cpc_read_ffh(int cpunum, struct cpc_reg *reg, u64 *val)
47 {
48 int err;
49
50 err = rdmsrl_safe_on_cpu(cpunum, reg->address, val);
51 if (!err) {
52 u64 mask = GENMASK_ULL(reg->bit_offset + reg->bit_width - 1,
53 reg->bit_offset);
54
55 *val &= mask;
56 *val >>= reg->bit_offset;
57 }
58 return err;
59 }
60
cpc_write_ffh(int cpunum,struct cpc_reg * reg,u64 val)61 int cpc_write_ffh(int cpunum, struct cpc_reg *reg, u64 val)
62 {
63 u64 rd_val;
64 int err;
65
66 err = rdmsrl_safe_on_cpu(cpunum, reg->address, &rd_val);
67 if (!err) {
68 u64 mask = GENMASK_ULL(reg->bit_offset + reg->bit_width - 1,
69 reg->bit_offset);
70
71 val <<= reg->bit_offset;
72 val &= mask;
73 rd_val &= ~mask;
74 rd_val |= val;
75 err = wrmsrl_safe_on_cpu(cpunum, reg->address, rd_val);
76 }
77 return err;
78 }
79
amd_set_max_freq_ratio(void)80 static void amd_set_max_freq_ratio(void)
81 {
82 struct cppc_perf_caps perf_caps;
83 u64 numerator, nominal_perf;
84 u64 perf_ratio;
85 int rc;
86
87 rc = cppc_get_perf_caps(0, &perf_caps);
88 if (rc) {
89 pr_warn("Could not retrieve perf counters (%d)\n", rc);
90 return;
91 }
92
93 rc = amd_get_boost_ratio_numerator(0, &numerator);
94 if (rc) {
95 pr_warn("Could not retrieve highest performance (%d)\n", rc);
96 return;
97 }
98 nominal_perf = perf_caps.nominal_perf;
99
100 if (!nominal_perf) {
101 pr_warn("Could not retrieve nominal performance\n");
102 return;
103 }
104
105 /* midpoint between max_boost and max_P */
106 perf_ratio = (div_u64(numerator * SCHED_CAPACITY_SCALE, nominal_perf) + SCHED_CAPACITY_SCALE) >> 1;
107
108 freq_invariance_set_perf_ratio(perf_ratio, false);
109 }
110
111 static DEFINE_MUTEX(freq_invariance_lock);
112
init_freq_invariance_cppc(void)113 static inline void init_freq_invariance_cppc(void)
114 {
115 static bool init_done;
116
117 if (!cpu_feature_enabled(X86_FEATURE_APERFMPERF))
118 return;
119
120 if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD)
121 return;
122
123 mutex_lock(&freq_invariance_lock);
124 if (!init_done)
125 amd_set_max_freq_ratio();
126 init_done = true;
127 mutex_unlock(&freq_invariance_lock);
128 }
129
acpi_processor_init_invariance_cppc(void)130 void acpi_processor_init_invariance_cppc(void)
131 {
132 init_freq_invariance_cppc();
133 }
134
135 /*
136 * Get the highest performance register value.
137 * @cpu: CPU from which to get highest performance.
138 * @highest_perf: Return address for highest performance value.
139 *
140 * Return: 0 for success, negative error code otherwise.
141 */
amd_get_highest_perf(unsigned int cpu,u32 * highest_perf)142 int amd_get_highest_perf(unsigned int cpu, u32 *highest_perf)
143 {
144 u64 val;
145 int ret;
146
147 if (cpu_feature_enabled(X86_FEATURE_CPPC)) {
148 ret = rdmsrl_safe_on_cpu(cpu, MSR_AMD_CPPC_CAP1, &val);
149 if (ret)
150 goto out;
151
152 val = AMD_CPPC_HIGHEST_PERF(val);
153 } else {
154 ret = cppc_get_highest_perf(cpu, &val);
155 if (ret)
156 goto out;
157 }
158
159 WRITE_ONCE(*highest_perf, (u32)val);
160 out:
161 return ret;
162 }
163 EXPORT_SYMBOL_GPL(amd_get_highest_perf);
164
165 /**
166 * amd_detect_prefcore: Detect if CPUs in the system support preferred cores
167 * @detected: Output variable for the result of the detection.
168 *
169 * Determine whether CPUs in the system support preferred cores. On systems
170 * that support preferred cores, different highest perf values will be found
171 * on different cores. On other systems, the highest perf value will be the
172 * same on all cores.
173 *
174 * The result of the detection will be stored in the 'detected' parameter.
175 *
176 * Return: 0 for success, negative error code otherwise
177 */
amd_detect_prefcore(bool * detected)178 int amd_detect_prefcore(bool *detected)
179 {
180 int cpu, count = 0;
181 u64 highest_perf[2] = {0};
182
183 if (WARN_ON(!detected))
184 return -EINVAL;
185
186 switch (amd_pref_core_detected) {
187 case AMD_PREF_CORE_SUPPORTED:
188 *detected = true;
189 return 0;
190 case AMD_PREF_CORE_UNSUPPORTED:
191 *detected = false;
192 return 0;
193 default:
194 break;
195 }
196
197 for_each_present_cpu(cpu) {
198 u32 tmp;
199 int ret;
200
201 ret = amd_get_highest_perf(cpu, &tmp);
202 if (ret)
203 return ret;
204
205 if (!count || (count == 1 && tmp != highest_perf[0]))
206 highest_perf[count++] = tmp;
207
208 if (count == 2)
209 break;
210 }
211
212 *detected = (count == 2);
213 boost_numerator = highest_perf[0];
214
215 amd_pref_core_detected = *detected ? AMD_PREF_CORE_SUPPORTED :
216 AMD_PREF_CORE_UNSUPPORTED;
217
218 pr_debug("AMD CPPC preferred core is %ssupported (highest perf: 0x%llx)\n",
219 *detected ? "" : "un", highest_perf[0]);
220
221 return 0;
222 }
223 EXPORT_SYMBOL_GPL(amd_detect_prefcore);
224
225 /**
226 * amd_get_boost_ratio_numerator: Get the numerator to use for boost ratio calculation
227 * @cpu: CPU to get numerator for.
228 * @numerator: Output variable for numerator.
229 *
230 * Determine the numerator to use for calculating the boost ratio on
231 * a CPU. On systems that support preferred cores, this will be a hardcoded
232 * value. On other systems this will the highest performance register value.
233 *
234 * If booting the system with amd-pstate enabled but preferred cores disabled then
235 * the correct boost numerator will be returned to match hardware capabilities
236 * even if the preferred cores scheduling hints are not enabled.
237 *
238 * Return: 0 for success, negative error code otherwise.
239 */
amd_get_boost_ratio_numerator(unsigned int cpu,u64 * numerator)240 int amd_get_boost_ratio_numerator(unsigned int cpu, u64 *numerator)
241 {
242 enum x86_topology_cpu_type core_type = get_topology_cpu_type(&cpu_data(cpu));
243 bool prefcore;
244 int ret;
245 u32 tmp;
246
247 ret = amd_detect_prefcore(&prefcore);
248 if (ret)
249 return ret;
250
251 /* without preferred cores, return the highest perf register value */
252 if (!prefcore) {
253 *numerator = boost_numerator;
254 return 0;
255 }
256
257 /*
258 * For AMD CPUs with Family ID 19H and Model ID range 0x70 to 0x7f,
259 * the highest performance level is set to 196.
260 * https://bugzilla.kernel.org/show_bug.cgi?id=218759
261 */
262 if (cpu_feature_enabled(X86_FEATURE_ZEN4)) {
263 switch (boot_cpu_data.x86_model) {
264 case 0x70 ... 0x7f:
265 *numerator = CPPC_HIGHEST_PERF_PERFORMANCE;
266 return 0;
267 default:
268 break;
269 }
270 }
271
272 /* detect if running on heterogeneous design */
273 if (cpu_feature_enabled(X86_FEATURE_AMD_HETEROGENEOUS_CORES)) {
274 switch (core_type) {
275 case TOPO_CPU_TYPE_UNKNOWN:
276 pr_warn("Undefined core type found for cpu %d\n", cpu);
277 break;
278 case TOPO_CPU_TYPE_PERFORMANCE:
279 /* use the max scale for performance cores */
280 *numerator = CPPC_HIGHEST_PERF_PERFORMANCE;
281 return 0;
282 case TOPO_CPU_TYPE_EFFICIENCY:
283 /* use the highest perf value for efficiency cores */
284 ret = amd_get_highest_perf(cpu, &tmp);
285 if (ret)
286 return ret;
287 *numerator = tmp;
288 return 0;
289 }
290 }
291
292 *numerator = CPPC_HIGHEST_PERF_PREFCORE;
293
294 return 0;
295 }
296 EXPORT_SYMBOL_GPL(amd_get_boost_ratio_numerator);
297