Commit | Line | Data |
---|---|---|
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> | |
cf30af76 | 29 | #include <linux/reboot.h> |
b3d627a5 VS |
30 | |
31 | #include <asm/cputhreads.h> | |
6174bac8 | 32 | #include <asm/firmware.h> |
b3d627a5 | 33 | #include <asm/reg.h> |
f3cae355 | 34 | #include <asm/smp.h> /* Required for cpu_sibling_mask() in UP configs */ |
b3d627a5 VS |
35 | |
36 | #define POWERNV_MAX_PSTATES 256 | |
37 | ||
38 | static struct cpufreq_frequency_table powernv_freqs[POWERNV_MAX_PSTATES+1]; | |
cf30af76 | 39 | static bool rebooting; |
b3d627a5 VS |
40 | |
41 | /* | |
42 | * Note: The set of pstates consists of contiguous integers, the | |
43 | * smallest of which is indicated by powernv_pstate_info.min, the | |
44 | * largest of which is indicated by powernv_pstate_info.max. | |
45 | * | |
46 | * The nominal pstate is the highest non-turbo pstate in this | |
47 | * platform. This is indicated by powernv_pstate_info.nominal. | |
48 | */ | |
49 | static struct powernv_pstate_info { | |
50 | int min; | |
51 | int max; | |
52 | int nominal; | |
53 | int nr_pstates; | |
54 | } powernv_pstate_info; | |
55 | ||
56 | /* | |
57 | * Initialize the freq table based on data obtained | |
58 | * from the firmware passed via device-tree | |
59 | */ | |
60 | static int init_powernv_pstates(void) | |
61 | { | |
62 | struct device_node *power_mgt; | |
63 | int i, pstate_min, pstate_max, pstate_nominal, nr_pstates = 0; | |
64 | const __be32 *pstate_ids, *pstate_freqs; | |
65 | u32 len_ids, len_freqs; | |
66 | ||
67 | power_mgt = of_find_node_by_path("/ibm,opal/power-mgt"); | |
68 | if (!power_mgt) { | |
69 | pr_warn("power-mgt node not found\n"); | |
70 | return -ENODEV; | |
71 | } | |
72 | ||
73 | if (of_property_read_u32(power_mgt, "ibm,pstate-min", &pstate_min)) { | |
74 | pr_warn("ibm,pstate-min node not found\n"); | |
75 | return -ENODEV; | |
76 | } | |
77 | ||
78 | if (of_property_read_u32(power_mgt, "ibm,pstate-max", &pstate_max)) { | |
79 | pr_warn("ibm,pstate-max node not found\n"); | |
80 | return -ENODEV; | |
81 | } | |
82 | ||
83 | if (of_property_read_u32(power_mgt, "ibm,pstate-nominal", | |
84 | &pstate_nominal)) { | |
85 | pr_warn("ibm,pstate-nominal not found\n"); | |
86 | return -ENODEV; | |
87 | } | |
88 | pr_info("cpufreq pstate min %d nominal %d max %d\n", pstate_min, | |
89 | pstate_nominal, pstate_max); | |
90 | ||
91 | pstate_ids = of_get_property(power_mgt, "ibm,pstate-ids", &len_ids); | |
92 | if (!pstate_ids) { | |
93 | pr_warn("ibm,pstate-ids not found\n"); | |
94 | return -ENODEV; | |
95 | } | |
96 | ||
97 | pstate_freqs = of_get_property(power_mgt, "ibm,pstate-frequencies-mhz", | |
98 | &len_freqs); | |
99 | if (!pstate_freqs) { | |
100 | pr_warn("ibm,pstate-frequencies-mhz not found\n"); | |
101 | return -ENODEV; | |
102 | } | |
103 | ||
6174bac8 VS |
104 | if (len_ids != len_freqs) { |
105 | pr_warn("Entries in ibm,pstate-ids and " | |
106 | "ibm,pstate-frequencies-mhz does not match\n"); | |
107 | } | |
108 | ||
b3d627a5 VS |
109 | nr_pstates = min(len_ids, len_freqs) / sizeof(u32); |
110 | if (!nr_pstates) { | |
111 | pr_warn("No PStates found\n"); | |
112 | return -ENODEV; | |
113 | } | |
114 | ||
115 | pr_debug("NR PStates %d\n", nr_pstates); | |
116 | for (i = 0; i < nr_pstates; i++) { | |
117 | u32 id = be32_to_cpu(pstate_ids[i]); | |
118 | u32 freq = be32_to_cpu(pstate_freqs[i]); | |
119 | ||
120 | pr_debug("PState id %d freq %d MHz\n", id, freq); | |
121 | powernv_freqs[i].frequency = freq * 1000; /* kHz */ | |
0692c691 | 122 | powernv_freqs[i].driver_data = id; |
b3d627a5 VS |
123 | } |
124 | /* End of list marker entry */ | |
125 | powernv_freqs[i].frequency = CPUFREQ_TABLE_END; | |
126 | ||
127 | powernv_pstate_info.min = pstate_min; | |
128 | powernv_pstate_info.max = pstate_max; | |
129 | powernv_pstate_info.nominal = pstate_nominal; | |
130 | powernv_pstate_info.nr_pstates = nr_pstates; | |
131 | ||
132 | return 0; | |
133 | } | |
134 | ||
135 | /* Returns the CPU frequency corresponding to the pstate_id. */ | |
136 | static unsigned int pstate_id_to_freq(int pstate_id) | |
137 | { | |
138 | int i; | |
139 | ||
140 | i = powernv_pstate_info.max - pstate_id; | |
6174bac8 VS |
141 | if (i >= powernv_pstate_info.nr_pstates || i < 0) { |
142 | pr_warn("PState id %d outside of PState table, " | |
143 | "reporting nominal id %d instead\n", | |
144 | pstate_id, powernv_pstate_info.nominal); | |
145 | i = powernv_pstate_info.max - powernv_pstate_info.nominal; | |
146 | } | |
b3d627a5 VS |
147 | |
148 | return powernv_freqs[i].frequency; | |
149 | } | |
150 | ||
151 | /* | |
152 | * cpuinfo_nominal_freq_show - Show the nominal CPU frequency as indicated by | |
153 | * the firmware | |
154 | */ | |
155 | static ssize_t cpuinfo_nominal_freq_show(struct cpufreq_policy *policy, | |
156 | char *buf) | |
157 | { | |
158 | return sprintf(buf, "%u\n", | |
159 | pstate_id_to_freq(powernv_pstate_info.nominal)); | |
160 | } | |
161 | ||
162 | struct freq_attr cpufreq_freq_attr_cpuinfo_nominal_freq = | |
163 | __ATTR_RO(cpuinfo_nominal_freq); | |
164 | ||
165 | static struct freq_attr *powernv_cpu_freq_attr[] = { | |
166 | &cpufreq_freq_attr_scaling_available_freqs, | |
167 | &cpufreq_freq_attr_cpuinfo_nominal_freq, | |
168 | NULL, | |
169 | }; | |
170 | ||
171 | /* Helper routines */ | |
172 | ||
173 | /* Access helpers to power mgt SPR */ | |
174 | ||
175 | static inline unsigned long get_pmspr(unsigned long sprn) | |
176 | { | |
177 | switch (sprn) { | |
178 | case SPRN_PMCR: | |
179 | return mfspr(SPRN_PMCR); | |
180 | ||
181 | case SPRN_PMICR: | |
182 | return mfspr(SPRN_PMICR); | |
183 | ||
184 | case SPRN_PMSR: | |
185 | return mfspr(SPRN_PMSR); | |
186 | } | |
187 | BUG(); | |
188 | } | |
189 | ||
190 | static inline void set_pmspr(unsigned long sprn, unsigned long val) | |
191 | { | |
192 | switch (sprn) { | |
193 | case SPRN_PMCR: | |
194 | mtspr(SPRN_PMCR, val); | |
195 | return; | |
196 | ||
197 | case SPRN_PMICR: | |
198 | mtspr(SPRN_PMICR, val); | |
199 | return; | |
200 | } | |
201 | BUG(); | |
202 | } | |
203 | ||
204 | /* | |
205 | * Use objects of this type to query/update | |
206 | * pstates on a remote CPU via smp_call_function. | |
207 | */ | |
208 | struct powernv_smp_call_data { | |
209 | unsigned int freq; | |
210 | int pstate_id; | |
211 | }; | |
212 | ||
213 | /* | |
214 | * powernv_read_cpu_freq: Reads the current frequency on this CPU. | |
215 | * | |
216 | * Called via smp_call_function. | |
217 | * | |
218 | * Note: The caller of the smp_call_function should pass an argument of | |
219 | * the type 'struct powernv_smp_call_data *' along with this function. | |
220 | * | |
221 | * The current frequency on this CPU will be returned via | |
222 | * ((struct powernv_smp_call_data *)arg)->freq; | |
223 | */ | |
224 | static void powernv_read_cpu_freq(void *arg) | |
225 | { | |
226 | unsigned long pmspr_val; | |
227 | s8 local_pstate_id; | |
228 | struct powernv_smp_call_data *freq_data = arg; | |
229 | ||
230 | pmspr_val = get_pmspr(SPRN_PMSR); | |
231 | ||
232 | /* | |
233 | * The local pstate id corresponds bits 48..55 in the PMSR. | |
234 | * Note: Watch out for the sign! | |
235 | */ | |
236 | local_pstate_id = (pmspr_val >> 48) & 0xFF; | |
237 | freq_data->pstate_id = local_pstate_id; | |
238 | freq_data->freq = pstate_id_to_freq(freq_data->pstate_id); | |
239 | ||
240 | pr_debug("cpu %d pmsr %016lX pstate_id %d frequency %d kHz\n", | |
241 | raw_smp_processor_id(), pmspr_val, freq_data->pstate_id, | |
242 | freq_data->freq); | |
243 | } | |
244 | ||
245 | /* | |
246 | * powernv_cpufreq_get: Returns the CPU frequency as reported by the | |
247 | * firmware for CPU 'cpu'. This value is reported through the sysfs | |
248 | * file cpuinfo_cur_freq. | |
249 | */ | |
60d1ea4e | 250 | static unsigned int powernv_cpufreq_get(unsigned int cpu) |
b3d627a5 VS |
251 | { |
252 | struct powernv_smp_call_data freq_data; | |
253 | ||
254 | smp_call_function_any(cpu_sibling_mask(cpu), powernv_read_cpu_freq, | |
255 | &freq_data, 1); | |
256 | ||
257 | return freq_data.freq; | |
258 | } | |
259 | ||
260 | /* | |
261 | * set_pstate: Sets the pstate on this CPU. | |
262 | * | |
263 | * This is called via an smp_call_function. | |
264 | * | |
265 | * The caller must ensure that freq_data is of the type | |
266 | * (struct powernv_smp_call_data *) and the pstate_id which needs to be set | |
267 | * on this CPU should be present in freq_data->pstate_id. | |
268 | */ | |
269 | static void set_pstate(void *freq_data) | |
270 | { | |
271 | unsigned long val; | |
272 | unsigned long pstate_ul = | |
273 | ((struct powernv_smp_call_data *) freq_data)->pstate_id; | |
274 | ||
275 | val = get_pmspr(SPRN_PMCR); | |
276 | val = val & 0x0000FFFFFFFFFFFFULL; | |
277 | ||
278 | pstate_ul = pstate_ul & 0xFF; | |
279 | ||
280 | /* Set both global(bits 56..63) and local(bits 48..55) PStates */ | |
281 | val = val | (pstate_ul << 56) | (pstate_ul << 48); | |
282 | ||
283 | pr_debug("Setting cpu %d pmcr to %016lX\n", | |
284 | raw_smp_processor_id(), val); | |
285 | set_pmspr(SPRN_PMCR, val); | |
286 | } | |
287 | ||
cf30af76 SB |
288 | /* |
289 | * get_nominal_index: Returns the index corresponding to the nominal | |
290 | * pstate in the cpufreq table | |
291 | */ | |
292 | static inline unsigned int get_nominal_index(void) | |
293 | { | |
294 | return powernv_pstate_info.max - powernv_pstate_info.nominal; | |
295 | } | |
296 | ||
b3d627a5 VS |
297 | /* |
298 | * powernv_cpufreq_target_index: Sets the frequency corresponding to | |
299 | * the cpufreq table entry indexed by new_index on the cpus in the | |
300 | * mask policy->cpus | |
301 | */ | |
302 | static int powernv_cpufreq_target_index(struct cpufreq_policy *policy, | |
303 | unsigned int new_index) | |
304 | { | |
305 | struct powernv_smp_call_data freq_data; | |
306 | ||
cf30af76 SB |
307 | if (unlikely(rebooting) && new_index != get_nominal_index()) |
308 | return 0; | |
309 | ||
0692c691 | 310 | freq_data.pstate_id = powernv_freqs[new_index].driver_data; |
b3d627a5 VS |
311 | |
312 | /* | |
313 | * Use smp_call_function to send IPI and execute the | |
314 | * mtspr on target CPU. We could do that without IPI | |
315 | * if current CPU is within policy->cpus (core) | |
316 | */ | |
317 | smp_call_function_any(policy->cpus, set_pstate, &freq_data, 1); | |
318 | ||
319 | return 0; | |
320 | } | |
321 | ||
322 | static int powernv_cpufreq_cpu_init(struct cpufreq_policy *policy) | |
323 | { | |
324 | int base, i; | |
325 | ||
326 | base = cpu_first_thread_sibling(policy->cpu); | |
327 | ||
328 | for (i = 0; i < threads_per_core; i++) | |
329 | cpumask_set_cpu(base + i, policy->cpus); | |
330 | ||
331 | return cpufreq_table_validate_and_show(policy, powernv_freqs); | |
332 | } | |
333 | ||
cf30af76 SB |
334 | static int powernv_cpufreq_reboot_notifier(struct notifier_block *nb, |
335 | unsigned long action, void *unused) | |
336 | { | |
337 | int cpu; | |
338 | struct cpufreq_policy cpu_policy; | |
339 | ||
340 | rebooting = true; | |
341 | for_each_online_cpu(cpu) { | |
342 | cpufreq_get_policy(&cpu_policy, cpu); | |
343 | powernv_cpufreq_target_index(&cpu_policy, get_nominal_index()); | |
344 | } | |
345 | ||
346 | return NOTIFY_DONE; | |
347 | } | |
348 | ||
349 | static struct notifier_block powernv_cpufreq_reboot_nb = { | |
350 | .notifier_call = powernv_cpufreq_reboot_notifier, | |
351 | }; | |
352 | ||
b120339c PM |
353 | static void powernv_cpufreq_stop_cpu(struct cpufreq_policy *policy) |
354 | { | |
355 | struct powernv_smp_call_data freq_data; | |
356 | ||
357 | freq_data.pstate_id = powernv_pstate_info.min; | |
358 | smp_call_function_single(policy->cpu, set_pstate, &freq_data, 1); | |
359 | } | |
360 | ||
b3d627a5 VS |
361 | static struct cpufreq_driver powernv_cpufreq_driver = { |
362 | .name = "powernv-cpufreq", | |
363 | .flags = CPUFREQ_CONST_LOOPS, | |
364 | .init = powernv_cpufreq_cpu_init, | |
365 | .verify = cpufreq_generic_frequency_table_verify, | |
366 | .target_index = powernv_cpufreq_target_index, | |
367 | .get = powernv_cpufreq_get, | |
b120339c | 368 | .stop_cpu = powernv_cpufreq_stop_cpu, |
b3d627a5 VS |
369 | .attr = powernv_cpu_freq_attr, |
370 | }; | |
371 | ||
372 | static int __init powernv_cpufreq_init(void) | |
373 | { | |
374 | int rc = 0; | |
375 | ||
6174bac8 VS |
376 | /* Don't probe on pseries (guest) platforms */ |
377 | if (!firmware_has_feature(FW_FEATURE_OPALv3)) | |
378 | return -ENODEV; | |
379 | ||
b3d627a5 VS |
380 | /* Discover pstates from device tree and init */ |
381 | rc = init_powernv_pstates(); | |
382 | if (rc) { | |
383 | pr_info("powernv-cpufreq disabled. System does not support PState control\n"); | |
384 | return rc; | |
385 | } | |
386 | ||
cf30af76 | 387 | register_reboot_notifier(&powernv_cpufreq_reboot_nb); |
b3d627a5 VS |
388 | return cpufreq_register_driver(&powernv_cpufreq_driver); |
389 | } | |
390 | module_init(powernv_cpufreq_init); | |
391 | ||
392 | static void __exit powernv_cpufreq_exit(void) | |
393 | { | |
cf30af76 | 394 | unregister_reboot_notifier(&powernv_cpufreq_reboot_nb); |
b3d627a5 VS |
395 | cpufreq_unregister_driver(&powernv_cpufreq_driver); |
396 | } | |
397 | module_exit(powernv_cpufreq_exit); | |
398 | ||
399 | MODULE_LICENSE("GPL"); | |
400 | MODULE_AUTHOR("Vaidyanathan Srinivasan <svaidy at linux.vnet.ibm.com>"); |