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b3d627a5 VS |
1 | /* |
2 | * POWERNV cpufreq driver for the IBM POWER processors | |
3 | * | |
4 | * (C) Copyright IBM 2014 | |
5 | * | |
6 | * Author: Vaidyanathan Srinivasan <svaidy at linux.vnet.ibm.com> | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License as published by | |
10 | * the Free Software Foundation; either version 2, or (at your option) | |
11 | * any later version. | |
12 | * | |
13 | * This program is distributed in the hope that it will be useful, | |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | * GNU General Public License for more details. | |
17 | * | |
18 | */ | |
19 | ||
20 | #define pr_fmt(fmt) "powernv-cpufreq: " fmt | |
21 | ||
22 | #include <linux/kernel.h> | |
23 | #include <linux/sysfs.h> | |
24 | #include <linux/cpumask.h> | |
25 | #include <linux/module.h> | |
26 | #include <linux/cpufreq.h> | |
27 | #include <linux/smp.h> | |
28 | #include <linux/of.h> | |
29 | ||
30 | #include <asm/cputhreads.h> | |
6174bac8 | 31 | #include <asm/firmware.h> |
b3d627a5 | 32 | #include <asm/reg.h> |
f3cae355 | 33 | #include <asm/smp.h> /* Required for cpu_sibling_mask() in UP configs */ |
b3d627a5 VS |
34 | |
35 | #define POWERNV_MAX_PSTATES 256 | |
36 | ||
37 | static struct cpufreq_frequency_table powernv_freqs[POWERNV_MAX_PSTATES+1]; | |
b3d627a5 VS |
38 | |
39 | /* | |
40 | * Note: The set of pstates consists of contiguous integers, the | |
41 | * smallest of which is indicated by powernv_pstate_info.min, the | |
42 | * largest of which is indicated by powernv_pstate_info.max. | |
43 | * | |
44 | * The nominal pstate is the highest non-turbo pstate in this | |
45 | * platform. This is indicated by powernv_pstate_info.nominal. | |
46 | */ | |
47 | static struct powernv_pstate_info { | |
48 | int min; | |
49 | int max; | |
50 | int nominal; | |
51 | int nr_pstates; | |
52 | } powernv_pstate_info; | |
53 | ||
54 | /* | |
55 | * Initialize the freq table based on data obtained | |
56 | * from the firmware passed via device-tree | |
57 | */ | |
58 | static int init_powernv_pstates(void) | |
59 | { | |
60 | struct device_node *power_mgt; | |
61 | int i, pstate_min, pstate_max, pstate_nominal, nr_pstates = 0; | |
62 | const __be32 *pstate_ids, *pstate_freqs; | |
63 | u32 len_ids, len_freqs; | |
64 | ||
65 | power_mgt = of_find_node_by_path("/ibm,opal/power-mgt"); | |
66 | if (!power_mgt) { | |
67 | pr_warn("power-mgt node not found\n"); | |
68 | return -ENODEV; | |
69 | } | |
70 | ||
71 | if (of_property_read_u32(power_mgt, "ibm,pstate-min", &pstate_min)) { | |
72 | pr_warn("ibm,pstate-min node not found\n"); | |
73 | return -ENODEV; | |
74 | } | |
75 | ||
76 | if (of_property_read_u32(power_mgt, "ibm,pstate-max", &pstate_max)) { | |
77 | pr_warn("ibm,pstate-max node not found\n"); | |
78 | return -ENODEV; | |
79 | } | |
80 | ||
81 | if (of_property_read_u32(power_mgt, "ibm,pstate-nominal", | |
82 | &pstate_nominal)) { | |
83 | pr_warn("ibm,pstate-nominal not found\n"); | |
84 | return -ENODEV; | |
85 | } | |
86 | pr_info("cpufreq pstate min %d nominal %d max %d\n", pstate_min, | |
87 | pstate_nominal, pstate_max); | |
88 | ||
89 | pstate_ids = of_get_property(power_mgt, "ibm,pstate-ids", &len_ids); | |
90 | if (!pstate_ids) { | |
91 | pr_warn("ibm,pstate-ids not found\n"); | |
92 | return -ENODEV; | |
93 | } | |
94 | ||
95 | pstate_freqs = of_get_property(power_mgt, "ibm,pstate-frequencies-mhz", | |
96 | &len_freqs); | |
97 | if (!pstate_freqs) { | |
98 | pr_warn("ibm,pstate-frequencies-mhz not found\n"); | |
99 | return -ENODEV; | |
100 | } | |
101 | ||
6174bac8 VS |
102 | if (len_ids != len_freqs) { |
103 | pr_warn("Entries in ibm,pstate-ids and " | |
104 | "ibm,pstate-frequencies-mhz does not match\n"); | |
105 | } | |
106 | ||
b3d627a5 VS |
107 | nr_pstates = min(len_ids, len_freqs) / sizeof(u32); |
108 | if (!nr_pstates) { | |
109 | pr_warn("No PStates found\n"); | |
110 | return -ENODEV; | |
111 | } | |
112 | ||
113 | pr_debug("NR PStates %d\n", nr_pstates); | |
114 | for (i = 0; i < nr_pstates; i++) { | |
115 | u32 id = be32_to_cpu(pstate_ids[i]); | |
116 | u32 freq = be32_to_cpu(pstate_freqs[i]); | |
117 | ||
118 | pr_debug("PState id %d freq %d MHz\n", id, freq); | |
119 | powernv_freqs[i].frequency = freq * 1000; /* kHz */ | |
0692c691 | 120 | powernv_freqs[i].driver_data = id; |
b3d627a5 VS |
121 | } |
122 | /* End of list marker entry */ | |
123 | powernv_freqs[i].frequency = CPUFREQ_TABLE_END; | |
124 | ||
125 | powernv_pstate_info.min = pstate_min; | |
126 | powernv_pstate_info.max = pstate_max; | |
127 | powernv_pstate_info.nominal = pstate_nominal; | |
128 | powernv_pstate_info.nr_pstates = nr_pstates; | |
129 | ||
130 | return 0; | |
131 | } | |
132 | ||
133 | /* Returns the CPU frequency corresponding to the pstate_id. */ | |
134 | static unsigned int pstate_id_to_freq(int pstate_id) | |
135 | { | |
136 | int i; | |
137 | ||
138 | i = powernv_pstate_info.max - pstate_id; | |
6174bac8 VS |
139 | if (i >= powernv_pstate_info.nr_pstates || i < 0) { |
140 | pr_warn("PState id %d outside of PState table, " | |
141 | "reporting nominal id %d instead\n", | |
142 | pstate_id, powernv_pstate_info.nominal); | |
143 | i = powernv_pstate_info.max - powernv_pstate_info.nominal; | |
144 | } | |
b3d627a5 VS |
145 | |
146 | return powernv_freqs[i].frequency; | |
147 | } | |
148 | ||
149 | /* | |
150 | * cpuinfo_nominal_freq_show - Show the nominal CPU frequency as indicated by | |
151 | * the firmware | |
152 | */ | |
153 | static ssize_t cpuinfo_nominal_freq_show(struct cpufreq_policy *policy, | |
154 | char *buf) | |
155 | { | |
156 | return sprintf(buf, "%u\n", | |
157 | pstate_id_to_freq(powernv_pstate_info.nominal)); | |
158 | } | |
159 | ||
160 | struct freq_attr cpufreq_freq_attr_cpuinfo_nominal_freq = | |
161 | __ATTR_RO(cpuinfo_nominal_freq); | |
162 | ||
163 | static struct freq_attr *powernv_cpu_freq_attr[] = { | |
164 | &cpufreq_freq_attr_scaling_available_freqs, | |
165 | &cpufreq_freq_attr_cpuinfo_nominal_freq, | |
166 | NULL, | |
167 | }; | |
168 | ||
169 | /* Helper routines */ | |
170 | ||
171 | /* Access helpers to power mgt SPR */ | |
172 | ||
173 | static inline unsigned long get_pmspr(unsigned long sprn) | |
174 | { | |
175 | switch (sprn) { | |
176 | case SPRN_PMCR: | |
177 | return mfspr(SPRN_PMCR); | |
178 | ||
179 | case SPRN_PMICR: | |
180 | return mfspr(SPRN_PMICR); | |
181 | ||
182 | case SPRN_PMSR: | |
183 | return mfspr(SPRN_PMSR); | |
184 | } | |
185 | BUG(); | |
186 | } | |
187 | ||
188 | static inline void set_pmspr(unsigned long sprn, unsigned long val) | |
189 | { | |
190 | switch (sprn) { | |
191 | case SPRN_PMCR: | |
192 | mtspr(SPRN_PMCR, val); | |
193 | return; | |
194 | ||
195 | case SPRN_PMICR: | |
196 | mtspr(SPRN_PMICR, val); | |
197 | return; | |
198 | } | |
199 | BUG(); | |
200 | } | |
201 | ||
202 | /* | |
203 | * Use objects of this type to query/update | |
204 | * pstates on a remote CPU via smp_call_function. | |
205 | */ | |
206 | struct powernv_smp_call_data { | |
207 | unsigned int freq; | |
208 | int pstate_id; | |
209 | }; | |
210 | ||
211 | /* | |
212 | * powernv_read_cpu_freq: Reads the current frequency on this CPU. | |
213 | * | |
214 | * Called via smp_call_function. | |
215 | * | |
216 | * Note: The caller of the smp_call_function should pass an argument of | |
217 | * the type 'struct powernv_smp_call_data *' along with this function. | |
218 | * | |
219 | * The current frequency on this CPU will be returned via | |
220 | * ((struct powernv_smp_call_data *)arg)->freq; | |
221 | */ | |
222 | static void powernv_read_cpu_freq(void *arg) | |
223 | { | |
224 | unsigned long pmspr_val; | |
225 | s8 local_pstate_id; | |
226 | struct powernv_smp_call_data *freq_data = arg; | |
227 | ||
228 | pmspr_val = get_pmspr(SPRN_PMSR); | |
229 | ||
230 | /* | |
231 | * The local pstate id corresponds bits 48..55 in the PMSR. | |
232 | * Note: Watch out for the sign! | |
233 | */ | |
234 | local_pstate_id = (pmspr_val >> 48) & 0xFF; | |
235 | freq_data->pstate_id = local_pstate_id; | |
236 | freq_data->freq = pstate_id_to_freq(freq_data->pstate_id); | |
237 | ||
238 | pr_debug("cpu %d pmsr %016lX pstate_id %d frequency %d kHz\n", | |
239 | raw_smp_processor_id(), pmspr_val, freq_data->pstate_id, | |
240 | freq_data->freq); | |
241 | } | |
242 | ||
243 | /* | |
244 | * powernv_cpufreq_get: Returns the CPU frequency as reported by the | |
245 | * firmware for CPU 'cpu'. This value is reported through the sysfs | |
246 | * file cpuinfo_cur_freq. | |
247 | */ | |
60d1ea4e | 248 | static unsigned int powernv_cpufreq_get(unsigned int cpu) |
b3d627a5 VS |
249 | { |
250 | struct powernv_smp_call_data freq_data; | |
251 | ||
252 | smp_call_function_any(cpu_sibling_mask(cpu), powernv_read_cpu_freq, | |
253 | &freq_data, 1); | |
254 | ||
255 | return freq_data.freq; | |
256 | } | |
257 | ||
258 | /* | |
259 | * set_pstate: Sets the pstate on this CPU. | |
260 | * | |
261 | * This is called via an smp_call_function. | |
262 | * | |
263 | * The caller must ensure that freq_data is of the type | |
264 | * (struct powernv_smp_call_data *) and the pstate_id which needs to be set | |
265 | * on this CPU should be present in freq_data->pstate_id. | |
266 | */ | |
267 | static void set_pstate(void *freq_data) | |
268 | { | |
269 | unsigned long val; | |
270 | unsigned long pstate_ul = | |
271 | ((struct powernv_smp_call_data *) freq_data)->pstate_id; | |
272 | ||
273 | val = get_pmspr(SPRN_PMCR); | |
274 | val = val & 0x0000FFFFFFFFFFFFULL; | |
275 | ||
276 | pstate_ul = pstate_ul & 0xFF; | |
277 | ||
278 | /* Set both global(bits 56..63) and local(bits 48..55) PStates */ | |
279 | val = val | (pstate_ul << 56) | (pstate_ul << 48); | |
280 | ||
281 | pr_debug("Setting cpu %d pmcr to %016lX\n", | |
282 | raw_smp_processor_id(), val); | |
283 | set_pmspr(SPRN_PMCR, val); | |
284 | } | |
285 | ||
286 | /* | |
287 | * powernv_cpufreq_target_index: Sets the frequency corresponding to | |
288 | * the cpufreq table entry indexed by new_index on the cpus in the | |
289 | * mask policy->cpus | |
290 | */ | |
291 | static int powernv_cpufreq_target_index(struct cpufreq_policy *policy, | |
292 | unsigned int new_index) | |
293 | { | |
294 | struct powernv_smp_call_data freq_data; | |
295 | ||
0692c691 | 296 | freq_data.pstate_id = powernv_freqs[new_index].driver_data; |
b3d627a5 VS |
297 | |
298 | /* | |
299 | * Use smp_call_function to send IPI and execute the | |
300 | * mtspr on target CPU. We could do that without IPI | |
301 | * if current CPU is within policy->cpus (core) | |
302 | */ | |
303 | smp_call_function_any(policy->cpus, set_pstate, &freq_data, 1); | |
304 | ||
305 | return 0; | |
306 | } | |
307 | ||
308 | static int powernv_cpufreq_cpu_init(struct cpufreq_policy *policy) | |
309 | { | |
310 | int base, i; | |
311 | ||
312 | base = cpu_first_thread_sibling(policy->cpu); | |
313 | ||
314 | for (i = 0; i < threads_per_core; i++) | |
315 | cpumask_set_cpu(base + i, policy->cpus); | |
316 | ||
317 | return cpufreq_table_validate_and_show(policy, powernv_freqs); | |
318 | } | |
319 | ||
320 | static struct cpufreq_driver powernv_cpufreq_driver = { | |
321 | .name = "powernv-cpufreq", | |
322 | .flags = CPUFREQ_CONST_LOOPS, | |
323 | .init = powernv_cpufreq_cpu_init, | |
324 | .verify = cpufreq_generic_frequency_table_verify, | |
325 | .target_index = powernv_cpufreq_target_index, | |
326 | .get = powernv_cpufreq_get, | |
327 | .attr = powernv_cpu_freq_attr, | |
328 | }; | |
329 | ||
330 | static int __init powernv_cpufreq_init(void) | |
331 | { | |
332 | int rc = 0; | |
333 | ||
6174bac8 VS |
334 | /* Don't probe on pseries (guest) platforms */ |
335 | if (!firmware_has_feature(FW_FEATURE_OPALv3)) | |
336 | return -ENODEV; | |
337 | ||
b3d627a5 VS |
338 | /* Discover pstates from device tree and init */ |
339 | rc = init_powernv_pstates(); | |
340 | if (rc) { | |
341 | pr_info("powernv-cpufreq disabled. System does not support PState control\n"); | |
342 | return rc; | |
343 | } | |
344 | ||
345 | return cpufreq_register_driver(&powernv_cpufreq_driver); | |
346 | } | |
347 | module_init(powernv_cpufreq_init); | |
348 | ||
349 | static void __exit powernv_cpufreq_exit(void) | |
350 | { | |
351 | cpufreq_unregister_driver(&powernv_cpufreq_driver); | |
352 | } | |
353 | module_exit(powernv_cpufreq_exit); | |
354 | ||
355 | MODULE_LICENSE("GPL"); | |
356 | MODULE_AUTHOR("Vaidyanathan Srinivasan <svaidy at linux.vnet.ibm.com>"); |