Vaidyanathan Srinivasan | b3d627a | 2014-04-01 12:43:26 +0530 | [diff] [blame] | 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> |
Shilpasri G Bhat | cf30af76 | 2014-09-29 15:49:11 +0200 | [diff] [blame^] | 29 | #include <linux/reboot.h> |
Vaidyanathan Srinivasan | b3d627a | 2014-04-01 12:43:26 +0530 | [diff] [blame] | 30 | |
| 31 | #include <asm/cputhreads.h> |
Vaidyanathan Srinivasan | 6174bac | 2014-08-03 14:54:05 +0530 | [diff] [blame] | 32 | #include <asm/firmware.h> |
Vaidyanathan Srinivasan | b3d627a | 2014-04-01 12:43:26 +0530 | [diff] [blame] | 33 | #include <asm/reg.h> |
Srivatsa S. Bhat | f3cae35 | 2014-04-16 11:35:38 +0530 | [diff] [blame] | 34 | #include <asm/smp.h> /* Required for cpu_sibling_mask() in UP configs */ |
Vaidyanathan Srinivasan | b3d627a | 2014-04-01 12:43:26 +0530 | [diff] [blame] | 35 | |
| 36 | #define POWERNV_MAX_PSTATES 256 |
| 37 | |
| 38 | static struct cpufreq_frequency_table powernv_freqs[POWERNV_MAX_PSTATES+1]; |
Shilpasri G Bhat | cf30af76 | 2014-09-29 15:49:11 +0200 | [diff] [blame^] | 39 | static bool rebooting; |
Vaidyanathan Srinivasan | b3d627a | 2014-04-01 12:43:26 +0530 | [diff] [blame] | 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 | |
Vaidyanathan Srinivasan | 6174bac | 2014-08-03 14:54:05 +0530 | [diff] [blame] | 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 | |
Vaidyanathan Srinivasan | b3d627a | 2014-04-01 12:43:26 +0530 | [diff] [blame] | 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 */ |
Gautham R. Shenoy | 0692c69 | 2014-04-01 12:43:27 +0530 | [diff] [blame] | 122 | powernv_freqs[i].driver_data = id; |
Vaidyanathan Srinivasan | b3d627a | 2014-04-01 12:43:26 +0530 | [diff] [blame] | 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; |
Vaidyanathan Srinivasan | 6174bac | 2014-08-03 14:54:05 +0530 | [diff] [blame] | 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 | } |
Vaidyanathan Srinivasan | b3d627a | 2014-04-01 12:43:26 +0530 | [diff] [blame] | 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 | */ |
Brian Norris | 60d1ea4 | 2014-05-11 00:51:20 -0700 | [diff] [blame] | 250 | static unsigned int powernv_cpufreq_get(unsigned int cpu) |
Vaidyanathan Srinivasan | b3d627a | 2014-04-01 12:43:26 +0530 | [diff] [blame] | 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 | |
| 288 | /* |
Shilpasri G Bhat | cf30af76 | 2014-09-29 15:49:11 +0200 | [diff] [blame^] | 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 | |
| 297 | /* |
Vaidyanathan Srinivasan | b3d627a | 2014-04-01 12:43:26 +0530 | [diff] [blame] | 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 | |
Shilpasri G Bhat | cf30af76 | 2014-09-29 15:49:11 +0200 | [diff] [blame^] | 307 | if (unlikely(rebooting) && new_index != get_nominal_index()) |
| 308 | return 0; |
| 309 | |
Gautham R. Shenoy | 0692c69 | 2014-04-01 12:43:27 +0530 | [diff] [blame] | 310 | freq_data.pstate_id = powernv_freqs[new_index].driver_data; |
Vaidyanathan Srinivasan | b3d627a | 2014-04-01 12:43:26 +0530 | [diff] [blame] | 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 | |
Shilpasri G Bhat | cf30af76 | 2014-09-29 15:49:11 +0200 | [diff] [blame^] | 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 | |
Preeti U Murthy | b120339 | 2014-09-29 15:47:53 +0200 | [diff] [blame] | 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 | |
Vaidyanathan Srinivasan | b3d627a | 2014-04-01 12:43:26 +0530 | [diff] [blame] | 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, |
Preeti U Murthy | b120339 | 2014-09-29 15:47:53 +0200 | [diff] [blame] | 368 | .stop_cpu = powernv_cpufreq_stop_cpu, |
Vaidyanathan Srinivasan | b3d627a | 2014-04-01 12:43:26 +0530 | [diff] [blame] | 369 | .attr = powernv_cpu_freq_attr, |
| 370 | }; |
| 371 | |
| 372 | static int __init powernv_cpufreq_init(void) |
| 373 | { |
| 374 | int rc = 0; |
| 375 | |
Vaidyanathan Srinivasan | 6174bac | 2014-08-03 14:54:05 +0530 | [diff] [blame] | 376 | /* Don't probe on pseries (guest) platforms */ |
| 377 | if (!firmware_has_feature(FW_FEATURE_OPALv3)) |
| 378 | return -ENODEV; |
| 379 | |
Vaidyanathan Srinivasan | b3d627a | 2014-04-01 12:43:26 +0530 | [diff] [blame] | 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 | |
Shilpasri G Bhat | cf30af76 | 2014-09-29 15:49:11 +0200 | [diff] [blame^] | 387 | register_reboot_notifier(&powernv_cpufreq_reboot_nb); |
Vaidyanathan Srinivasan | b3d627a | 2014-04-01 12:43:26 +0530 | [diff] [blame] | 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 | { |
Shilpasri G Bhat | cf30af76 | 2014-09-29 15:49:11 +0200 | [diff] [blame^] | 394 | unregister_reboot_notifier(&powernv_cpufreq_reboot_nb); |
Vaidyanathan Srinivasan | b3d627a | 2014-04-01 12:43:26 +0530 | [diff] [blame] | 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>"); |