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