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 #include <linux/reboot.h> 30 #include <linux/slab.h> 31 #include <linux/cpu.h> 32 #include <trace/events/power.h> 33 34 #include <asm/cputhreads.h> 35 #include <asm/firmware.h> 36 #include <asm/reg.h> 37 #include <asm/smp.h> /* Required for cpu_sibling_mask() in UP configs */ 38 #include <asm/opal.h> 39 #include <linux/timer.h> 40 41 #define POWERNV_MAX_PSTATES 256 42 #define PMSR_PSAFE_ENABLE (1UL << 30) 43 #define PMSR_SPR_EM_DISABLE (1UL << 31) 44 #define PMSR_MAX(x) ((x >> 32) & 0xFF) 45 46 #define MAX_RAMP_DOWN_TIME 5120 47 /* 48 * On an idle system we want the global pstate to ramp-down from max value to 49 * min over a span of ~5 secs. Also we want it to initially ramp-down slowly and 50 * then ramp-down rapidly later on. 51 * 52 * This gives a percentage rampdown for time elapsed in milliseconds. 53 * ramp_down_percentage = ((ms * ms) >> 18) 54 * ~= 3.8 * (sec * sec) 55 * 56 * At 0 ms ramp_down_percent = 0 57 * At 5120 ms ramp_down_percent = 100 58 */ 59 #define ramp_down_percent(time) ((time * time) >> 18) 60 61 /* Interval after which the timer is queued to bring down global pstate */ 62 #define GPSTATE_TIMER_INTERVAL 2000 63 64 /** 65 * struct global_pstate_info - Per policy data structure to maintain history of 66 * global pstates 67 * @highest_lpstate_idx: The local pstate index from which we are 68 * ramping down 69 * @elapsed_time: Time in ms spent in ramping down from 70 * highest_lpstate_idx 71 * @last_sampled_time: Time from boot in ms when global pstates were 72 * last set 73 * @last_lpstate_idx, Last set value of local pstate and global 74 * last_gpstate_idx pstate in terms of cpufreq table index 75 * @timer: Is used for ramping down if cpu goes idle for 76 * a long time with global pstate held high 77 * @gpstate_lock: A spinlock to maintain synchronization between 78 * routines called by the timer handler and 79 * governer's target_index calls 80 */ 81 struct global_pstate_info { 82 int highest_lpstate_idx; 83 unsigned int elapsed_time; 84 unsigned int last_sampled_time; 85 int last_lpstate_idx; 86 int last_gpstate_idx; 87 spinlock_t gpstate_lock; 88 struct timer_list timer; 89 }; 90 91 static struct cpufreq_frequency_table powernv_freqs[POWERNV_MAX_PSTATES+1]; 92 static bool rebooting, throttled, occ_reset; 93 94 static const char * const throttle_reason[] = { 95 "No throttling", 96 "Power Cap", 97 "Processor Over Temperature", 98 "Power Supply Failure", 99 "Over Current", 100 "OCC Reset" 101 }; 102 103 enum throttle_reason_type { 104 NO_THROTTLE = 0, 105 POWERCAP, 106 CPU_OVERTEMP, 107 POWER_SUPPLY_FAILURE, 108 OVERCURRENT, 109 OCC_RESET_THROTTLE, 110 OCC_MAX_REASON 111 }; 112 113 static struct chip { 114 unsigned int id; 115 bool throttled; 116 bool restore; 117 u8 throttle_reason; 118 cpumask_t mask; 119 struct work_struct throttle; 120 int throttle_turbo; 121 int throttle_sub_turbo; 122 int reason[OCC_MAX_REASON]; 123 } *chips; 124 125 static int nr_chips; 126 static DEFINE_PER_CPU(struct chip *, chip_info); 127 128 /* 129 * Note: 130 * The set of pstates consists of contiguous integers. 131 * powernv_pstate_info stores the index of the frequency table for 132 * max, min and nominal frequencies. It also stores number of 133 * available frequencies. 134 * 135 * powernv_pstate_info.nominal indicates the index to the highest 136 * non-turbo frequency. 137 */ 138 static struct powernv_pstate_info { 139 unsigned int min; 140 unsigned int max; 141 unsigned int nominal; 142 unsigned int nr_pstates; 143 } powernv_pstate_info; 144 145 /* Use following macros for conversions between pstate_id and index */ 146 static inline int idx_to_pstate(unsigned int i) 147 { 148 return powernv_freqs[i].driver_data; 149 } 150 151 static inline unsigned int pstate_to_idx(int pstate) 152 { 153 /* 154 * abs() is deliberately used so that is works with 155 * both monotonically increasing and decreasing 156 * pstate values 157 */ 158 return abs(pstate - idx_to_pstate(powernv_pstate_info.max)); 159 } 160 161 static inline void reset_gpstates(struct cpufreq_policy *policy) 162 { 163 struct global_pstate_info *gpstates = policy->driver_data; 164 165 gpstates->highest_lpstate_idx = 0; 166 gpstates->elapsed_time = 0; 167 gpstates->last_sampled_time = 0; 168 gpstates->last_lpstate_idx = 0; 169 gpstates->last_gpstate_idx = 0; 170 } 171 172 /* 173 * Initialize the freq table based on data obtained 174 * from the firmware passed via device-tree 175 */ 176 static int init_powernv_pstates(void) 177 { 178 struct device_node *power_mgt; 179 int i, nr_pstates = 0; 180 const __be32 *pstate_ids, *pstate_freqs; 181 u32 len_ids, len_freqs; 182 u32 pstate_min, pstate_max, pstate_nominal; 183 184 power_mgt = of_find_node_by_path("/ibm,opal/power-mgt"); 185 if (!power_mgt) { 186 pr_warn("power-mgt node not found\n"); 187 return -ENODEV; 188 } 189 190 if (of_property_read_u32(power_mgt, "ibm,pstate-min", &pstate_min)) { 191 pr_warn("ibm,pstate-min node not found\n"); 192 return -ENODEV; 193 } 194 195 if (of_property_read_u32(power_mgt, "ibm,pstate-max", &pstate_max)) { 196 pr_warn("ibm,pstate-max node not found\n"); 197 return -ENODEV; 198 } 199 200 if (of_property_read_u32(power_mgt, "ibm,pstate-nominal", 201 &pstate_nominal)) { 202 pr_warn("ibm,pstate-nominal not found\n"); 203 return -ENODEV; 204 } 205 pr_info("cpufreq pstate min %d nominal %d max %d\n", pstate_min, 206 pstate_nominal, pstate_max); 207 208 pstate_ids = of_get_property(power_mgt, "ibm,pstate-ids", &len_ids); 209 if (!pstate_ids) { 210 pr_warn("ibm,pstate-ids not found\n"); 211 return -ENODEV; 212 } 213 214 pstate_freqs = of_get_property(power_mgt, "ibm,pstate-frequencies-mhz", 215 &len_freqs); 216 if (!pstate_freqs) { 217 pr_warn("ibm,pstate-frequencies-mhz not found\n"); 218 return -ENODEV; 219 } 220 221 if (len_ids != len_freqs) { 222 pr_warn("Entries in ibm,pstate-ids and " 223 "ibm,pstate-frequencies-mhz does not match\n"); 224 } 225 226 nr_pstates = min(len_ids, len_freqs) / sizeof(u32); 227 if (!nr_pstates) { 228 pr_warn("No PStates found\n"); 229 return -ENODEV; 230 } 231 232 powernv_pstate_info.nr_pstates = nr_pstates; 233 pr_debug("NR PStates %d\n", nr_pstates); 234 for (i = 0; i < nr_pstates; i++) { 235 u32 id = be32_to_cpu(pstate_ids[i]); 236 u32 freq = be32_to_cpu(pstate_freqs[i]); 237 238 pr_debug("PState id %d freq %d MHz\n", id, freq); 239 powernv_freqs[i].frequency = freq * 1000; /* kHz */ 240 powernv_freqs[i].driver_data = id; 241 242 if (id == pstate_max) 243 powernv_pstate_info.max = i; 244 else if (id == pstate_nominal) 245 powernv_pstate_info.nominal = i; 246 else if (id == pstate_min) 247 powernv_pstate_info.min = i; 248 } 249 250 /* End of list marker entry */ 251 powernv_freqs[i].frequency = CPUFREQ_TABLE_END; 252 return 0; 253 } 254 255 /* Returns the CPU frequency corresponding to the pstate_id. */ 256 static unsigned int pstate_id_to_freq(int pstate_id) 257 { 258 int i; 259 260 i = pstate_to_idx(pstate_id); 261 if (i >= powernv_pstate_info.nr_pstates || i < 0) { 262 pr_warn("PState id %d outside of PState table, " 263 "reporting nominal id %d instead\n", 264 pstate_id, idx_to_pstate(powernv_pstate_info.nominal)); 265 i = powernv_pstate_info.nominal; 266 } 267 268 return powernv_freqs[i].frequency; 269 } 270 271 /* 272 * cpuinfo_nominal_freq_show - Show the nominal CPU frequency as indicated by 273 * the firmware 274 */ 275 static ssize_t cpuinfo_nominal_freq_show(struct cpufreq_policy *policy, 276 char *buf) 277 { 278 return sprintf(buf, "%u\n", 279 powernv_freqs[powernv_pstate_info.nominal].frequency); 280 } 281 282 struct freq_attr cpufreq_freq_attr_cpuinfo_nominal_freq = 283 __ATTR_RO(cpuinfo_nominal_freq); 284 285 static struct freq_attr *powernv_cpu_freq_attr[] = { 286 &cpufreq_freq_attr_scaling_available_freqs, 287 &cpufreq_freq_attr_cpuinfo_nominal_freq, 288 NULL, 289 }; 290 291 #define throttle_attr(name, member) \ 292 static ssize_t name##_show(struct cpufreq_policy *policy, char *buf) \ 293 { \ 294 struct chip *chip = per_cpu(chip_info, policy->cpu); \ 295 \ 296 return sprintf(buf, "%u\n", chip->member); \ 297 } \ 298 \ 299 static struct freq_attr throttle_attr_##name = __ATTR_RO(name) \ 300 301 throttle_attr(unthrottle, reason[NO_THROTTLE]); 302 throttle_attr(powercap, reason[POWERCAP]); 303 throttle_attr(overtemp, reason[CPU_OVERTEMP]); 304 throttle_attr(supply_fault, reason[POWER_SUPPLY_FAILURE]); 305 throttle_attr(overcurrent, reason[OVERCURRENT]); 306 throttle_attr(occ_reset, reason[OCC_RESET_THROTTLE]); 307 throttle_attr(turbo_stat, throttle_turbo); 308 throttle_attr(sub_turbo_stat, throttle_sub_turbo); 309 310 static struct attribute *throttle_attrs[] = { 311 &throttle_attr_unthrottle.attr, 312 &throttle_attr_powercap.attr, 313 &throttle_attr_overtemp.attr, 314 &throttle_attr_supply_fault.attr, 315 &throttle_attr_overcurrent.attr, 316 &throttle_attr_occ_reset.attr, 317 &throttle_attr_turbo_stat.attr, 318 &throttle_attr_sub_turbo_stat.attr, 319 NULL, 320 }; 321 322 static const struct attribute_group throttle_attr_grp = { 323 .name = "throttle_stats", 324 .attrs = throttle_attrs, 325 }; 326 327 /* Helper routines */ 328 329 /* Access helpers to power mgt SPR */ 330 331 static inline unsigned long get_pmspr(unsigned long sprn) 332 { 333 switch (sprn) { 334 case SPRN_PMCR: 335 return mfspr(SPRN_PMCR); 336 337 case SPRN_PMICR: 338 return mfspr(SPRN_PMICR); 339 340 case SPRN_PMSR: 341 return mfspr(SPRN_PMSR); 342 } 343 BUG(); 344 } 345 346 static inline void set_pmspr(unsigned long sprn, unsigned long val) 347 { 348 switch (sprn) { 349 case SPRN_PMCR: 350 mtspr(SPRN_PMCR, val); 351 return; 352 353 case SPRN_PMICR: 354 mtspr(SPRN_PMICR, val); 355 return; 356 } 357 BUG(); 358 } 359 360 /* 361 * Use objects of this type to query/update 362 * pstates on a remote CPU via smp_call_function. 363 */ 364 struct powernv_smp_call_data { 365 unsigned int freq; 366 int pstate_id; 367 int gpstate_id; 368 }; 369 370 /* 371 * powernv_read_cpu_freq: Reads the current frequency on this CPU. 372 * 373 * Called via smp_call_function. 374 * 375 * Note: The caller of the smp_call_function should pass an argument of 376 * the type 'struct powernv_smp_call_data *' along with this function. 377 * 378 * The current frequency on this CPU will be returned via 379 * ((struct powernv_smp_call_data *)arg)->freq; 380 */ 381 static void powernv_read_cpu_freq(void *arg) 382 { 383 unsigned long pmspr_val; 384 s8 local_pstate_id; 385 struct powernv_smp_call_data *freq_data = arg; 386 387 pmspr_val = get_pmspr(SPRN_PMSR); 388 389 /* 390 * The local pstate id corresponds bits 48..55 in the PMSR. 391 * Note: Watch out for the sign! 392 */ 393 local_pstate_id = (pmspr_val >> 48) & 0xFF; 394 freq_data->pstate_id = local_pstate_id; 395 freq_data->freq = pstate_id_to_freq(freq_data->pstate_id); 396 397 pr_debug("cpu %d pmsr %016lX pstate_id %d frequency %d kHz\n", 398 raw_smp_processor_id(), pmspr_val, freq_data->pstate_id, 399 freq_data->freq); 400 } 401 402 /* 403 * powernv_cpufreq_get: Returns the CPU frequency as reported by the 404 * firmware for CPU 'cpu'. This value is reported through the sysfs 405 * file cpuinfo_cur_freq. 406 */ 407 static unsigned int powernv_cpufreq_get(unsigned int cpu) 408 { 409 struct powernv_smp_call_data freq_data; 410 411 smp_call_function_any(cpu_sibling_mask(cpu), powernv_read_cpu_freq, 412 &freq_data, 1); 413 414 return freq_data.freq; 415 } 416 417 /* 418 * set_pstate: Sets the pstate on this CPU. 419 * 420 * This is called via an smp_call_function. 421 * 422 * The caller must ensure that freq_data is of the type 423 * (struct powernv_smp_call_data *) and the pstate_id which needs to be set 424 * on this CPU should be present in freq_data->pstate_id. 425 */ 426 static void set_pstate(void *data) 427 { 428 unsigned long val; 429 struct powernv_smp_call_data *freq_data = data; 430 unsigned long pstate_ul = freq_data->pstate_id; 431 unsigned long gpstate_ul = freq_data->gpstate_id; 432 433 val = get_pmspr(SPRN_PMCR); 434 val = val & 0x0000FFFFFFFFFFFFULL; 435 436 pstate_ul = pstate_ul & 0xFF; 437 gpstate_ul = gpstate_ul & 0xFF; 438 439 /* Set both global(bits 56..63) and local(bits 48..55) PStates */ 440 val = val | (gpstate_ul << 56) | (pstate_ul << 48); 441 442 pr_debug("Setting cpu %d pmcr to %016lX\n", 443 raw_smp_processor_id(), val); 444 set_pmspr(SPRN_PMCR, val); 445 } 446 447 /* 448 * get_nominal_index: Returns the index corresponding to the nominal 449 * pstate in the cpufreq table 450 */ 451 static inline unsigned int get_nominal_index(void) 452 { 453 return powernv_pstate_info.nominal; 454 } 455 456 static void powernv_cpufreq_throttle_check(void *data) 457 { 458 struct chip *chip; 459 unsigned int cpu = smp_processor_id(); 460 unsigned long pmsr; 461 int pmsr_pmax; 462 unsigned int pmsr_pmax_idx; 463 464 pmsr = get_pmspr(SPRN_PMSR); 465 chip = this_cpu_read(chip_info); 466 467 /* Check for Pmax Capping */ 468 pmsr_pmax = (s8)PMSR_MAX(pmsr); 469 pmsr_pmax_idx = pstate_to_idx(pmsr_pmax); 470 if (pmsr_pmax_idx != powernv_pstate_info.max) { 471 if (chip->throttled) 472 goto next; 473 chip->throttled = true; 474 if (pmsr_pmax_idx > powernv_pstate_info.nominal) { 475 pr_warn_once("CPU %d on Chip %u has Pmax(%d) reduced below nominal frequency(%d)\n", 476 cpu, chip->id, pmsr_pmax, 477 idx_to_pstate(powernv_pstate_info.nominal)); 478 chip->throttle_sub_turbo++; 479 } else { 480 chip->throttle_turbo++; 481 } 482 trace_powernv_throttle(chip->id, 483 throttle_reason[chip->throttle_reason], 484 pmsr_pmax); 485 } else if (chip->throttled) { 486 chip->throttled = false; 487 trace_powernv_throttle(chip->id, 488 throttle_reason[chip->throttle_reason], 489 pmsr_pmax); 490 } 491 492 /* Check if Psafe_mode_active is set in PMSR. */ 493 next: 494 if (pmsr & PMSR_PSAFE_ENABLE) { 495 throttled = true; 496 pr_info("Pstate set to safe frequency\n"); 497 } 498 499 /* Check if SPR_EM_DISABLE is set in PMSR */ 500 if (pmsr & PMSR_SPR_EM_DISABLE) { 501 throttled = true; 502 pr_info("Frequency Control disabled from OS\n"); 503 } 504 505 if (throttled) { 506 pr_info("PMSR = %16lx\n", pmsr); 507 pr_warn("CPU Frequency could be throttled\n"); 508 } 509 } 510 511 /** 512 * calc_global_pstate - Calculate global pstate 513 * @elapsed_time: Elapsed time in milliseconds 514 * @local_pstate_idx: New local pstate 515 * @highest_lpstate_idx: pstate from which its ramping down 516 * 517 * Finds the appropriate global pstate based on the pstate from which its 518 * ramping down and the time elapsed in ramping down. It follows a quadratic 519 * equation which ensures that it reaches ramping down to pmin in 5sec. 520 */ 521 static inline int calc_global_pstate(unsigned int elapsed_time, 522 int highest_lpstate_idx, 523 int local_pstate_idx) 524 { 525 int index_diff; 526 527 /* 528 * Using ramp_down_percent we get the percentage of rampdown 529 * that we are expecting to be dropping. Difference between 530 * highest_lpstate_idx and powernv_pstate_info.min will give a absolute 531 * number of how many pstates we will drop eventually by the end of 532 * 5 seconds, then just scale it get the number pstates to be dropped. 533 */ 534 index_diff = ((int)ramp_down_percent(elapsed_time) * 535 (powernv_pstate_info.min - highest_lpstate_idx)) / 100; 536 537 /* Ensure that global pstate is >= to local pstate */ 538 if (highest_lpstate_idx + index_diff >= local_pstate_idx) 539 return local_pstate_idx; 540 else 541 return highest_lpstate_idx + index_diff; 542 } 543 544 static inline void queue_gpstate_timer(struct global_pstate_info *gpstates) 545 { 546 unsigned int timer_interval; 547 548 /* 549 * Setting up timer to fire after GPSTATE_TIMER_INTERVAL ms, But 550 * if it exceeds MAX_RAMP_DOWN_TIME ms for ramp down time. 551 * Set timer such that it fires exactly at MAX_RAMP_DOWN_TIME 552 * seconds of ramp down time. 553 */ 554 if ((gpstates->elapsed_time + GPSTATE_TIMER_INTERVAL) 555 > MAX_RAMP_DOWN_TIME) 556 timer_interval = MAX_RAMP_DOWN_TIME - gpstates->elapsed_time; 557 else 558 timer_interval = GPSTATE_TIMER_INTERVAL; 559 560 mod_timer(&gpstates->timer, jiffies + msecs_to_jiffies(timer_interval)); 561 } 562 563 /** 564 * gpstate_timer_handler 565 * 566 * @data: pointer to cpufreq_policy on which timer was queued 567 * 568 * This handler brings down the global pstate closer to the local pstate 569 * according quadratic equation. Queues a new timer if it is still not equal 570 * to local pstate 571 */ 572 void gpstate_timer_handler(unsigned long data) 573 { 574 struct cpufreq_policy *policy = (struct cpufreq_policy *)data; 575 struct global_pstate_info *gpstates = policy->driver_data; 576 int gpstate_idx; 577 unsigned int time_diff = jiffies_to_msecs(jiffies) 578 - gpstates->last_sampled_time; 579 struct powernv_smp_call_data freq_data; 580 581 if (!spin_trylock(&gpstates->gpstate_lock)) 582 return; 583 584 gpstates->last_sampled_time += time_diff; 585 gpstates->elapsed_time += time_diff; 586 freq_data.pstate_id = idx_to_pstate(gpstates->last_lpstate_idx); 587 588 if ((gpstates->last_gpstate_idx == gpstates->last_lpstate_idx) || 589 (gpstates->elapsed_time > MAX_RAMP_DOWN_TIME)) { 590 gpstate_idx = pstate_to_idx(freq_data.pstate_id); 591 reset_gpstates(policy); 592 gpstates->highest_lpstate_idx = gpstate_idx; 593 } else { 594 gpstate_idx = calc_global_pstate(gpstates->elapsed_time, 595 gpstates->highest_lpstate_idx, 596 freq_data.pstate_id); 597 } 598 599 /* 600 * If local pstate is equal to global pstate, rampdown is over 601 * So timer is not required to be queued. 602 */ 603 if (gpstate_idx != gpstates->last_lpstate_idx) 604 queue_gpstate_timer(gpstates); 605 606 freq_data.gpstate_id = idx_to_pstate(gpstate_idx); 607 gpstates->last_gpstate_idx = pstate_to_idx(freq_data.gpstate_id); 608 gpstates->last_lpstate_idx = pstate_to_idx(freq_data.pstate_id); 609 610 spin_unlock(&gpstates->gpstate_lock); 611 612 /* Timer may get migrated to a different cpu on cpu hot unplug */ 613 smp_call_function_any(policy->cpus, set_pstate, &freq_data, 1); 614 } 615 616 /* 617 * powernv_cpufreq_target_index: Sets the frequency corresponding to 618 * the cpufreq table entry indexed by new_index on the cpus in the 619 * mask policy->cpus 620 */ 621 static int powernv_cpufreq_target_index(struct cpufreq_policy *policy, 622 unsigned int new_index) 623 { 624 struct powernv_smp_call_data freq_data; 625 unsigned int cur_msec, gpstate_idx; 626 struct global_pstate_info *gpstates = policy->driver_data; 627 628 if (unlikely(rebooting) && new_index != get_nominal_index()) 629 return 0; 630 631 if (!throttled) 632 powernv_cpufreq_throttle_check(NULL); 633 634 cur_msec = jiffies_to_msecs(get_jiffies_64()); 635 636 spin_lock(&gpstates->gpstate_lock); 637 freq_data.pstate_id = idx_to_pstate(new_index); 638 639 if (!gpstates->last_sampled_time) { 640 gpstate_idx = new_index; 641 gpstates->highest_lpstate_idx = new_index; 642 goto gpstates_done; 643 } 644 645 if (gpstates->last_gpstate_idx < new_index) { 646 gpstates->elapsed_time += cur_msec - 647 gpstates->last_sampled_time; 648 649 /* 650 * If its has been ramping down for more than MAX_RAMP_DOWN_TIME 651 * we should be resetting all global pstate related data. Set it 652 * equal to local pstate to start fresh. 653 */ 654 if (gpstates->elapsed_time > MAX_RAMP_DOWN_TIME) { 655 reset_gpstates(policy); 656 gpstates->highest_lpstate_idx = new_index; 657 gpstate_idx = new_index; 658 } else { 659 /* Elaspsed_time is less than 5 seconds, continue to rampdown */ 660 gpstate_idx = calc_global_pstate(gpstates->elapsed_time, 661 gpstates->highest_lpstate_idx, 662 new_index); 663 } 664 } else { 665 reset_gpstates(policy); 666 gpstates->highest_lpstate_idx = new_index; 667 gpstate_idx = new_index; 668 } 669 670 /* 671 * If local pstate is equal to global pstate, rampdown is over 672 * So timer is not required to be queued. 673 */ 674 if (gpstate_idx != new_index) 675 queue_gpstate_timer(gpstates); 676 else 677 del_timer_sync(&gpstates->timer); 678 679 gpstates_done: 680 freq_data.gpstate_id = idx_to_pstate(gpstate_idx); 681 gpstates->last_sampled_time = cur_msec; 682 gpstates->last_gpstate_idx = gpstate_idx; 683 gpstates->last_lpstate_idx = new_index; 684 685 spin_unlock(&gpstates->gpstate_lock); 686 687 /* 688 * Use smp_call_function to send IPI and execute the 689 * mtspr on target CPU. We could do that without IPI 690 * if current CPU is within policy->cpus (core) 691 */ 692 smp_call_function_any(policy->cpus, set_pstate, &freq_data, 1); 693 return 0; 694 } 695 696 static int powernv_cpufreq_cpu_init(struct cpufreq_policy *policy) 697 { 698 int base, i, ret; 699 struct kernfs_node *kn; 700 struct global_pstate_info *gpstates; 701 702 base = cpu_first_thread_sibling(policy->cpu); 703 704 for (i = 0; i < threads_per_core; i++) 705 cpumask_set_cpu(base + i, policy->cpus); 706 707 kn = kernfs_find_and_get(policy->kobj.sd, throttle_attr_grp.name); 708 if (!kn) { 709 int ret; 710 711 ret = sysfs_create_group(&policy->kobj, &throttle_attr_grp); 712 if (ret) { 713 pr_info("Failed to create throttle stats directory for cpu %d\n", 714 policy->cpu); 715 return ret; 716 } 717 } else { 718 kernfs_put(kn); 719 } 720 721 gpstates = kzalloc(sizeof(*gpstates), GFP_KERNEL); 722 if (!gpstates) 723 return -ENOMEM; 724 725 policy->driver_data = gpstates; 726 727 /* initialize timer */ 728 init_timer_pinned_deferrable(&gpstates->timer); 729 gpstates->timer.data = (unsigned long)policy; 730 gpstates->timer.function = gpstate_timer_handler; 731 gpstates->timer.expires = jiffies + 732 msecs_to_jiffies(GPSTATE_TIMER_INTERVAL); 733 spin_lock_init(&gpstates->gpstate_lock); 734 ret = cpufreq_table_validate_and_show(policy, powernv_freqs); 735 736 if (ret < 0) 737 kfree(policy->driver_data); 738 739 return ret; 740 } 741 742 static int powernv_cpufreq_cpu_exit(struct cpufreq_policy *policy) 743 { 744 /* timer is deleted in cpufreq_cpu_stop() */ 745 kfree(policy->driver_data); 746 747 return 0; 748 } 749 750 static int powernv_cpufreq_reboot_notifier(struct notifier_block *nb, 751 unsigned long action, void *unused) 752 { 753 int cpu; 754 struct cpufreq_policy cpu_policy; 755 756 rebooting = true; 757 for_each_online_cpu(cpu) { 758 cpufreq_get_policy(&cpu_policy, cpu); 759 powernv_cpufreq_target_index(&cpu_policy, get_nominal_index()); 760 } 761 762 return NOTIFY_DONE; 763 } 764 765 static struct notifier_block powernv_cpufreq_reboot_nb = { 766 .notifier_call = powernv_cpufreq_reboot_notifier, 767 }; 768 769 void powernv_cpufreq_work_fn(struct work_struct *work) 770 { 771 struct chip *chip = container_of(work, struct chip, throttle); 772 unsigned int cpu; 773 cpumask_t mask; 774 775 get_online_cpus(); 776 cpumask_and(&mask, &chip->mask, cpu_online_mask); 777 smp_call_function_any(&mask, 778 powernv_cpufreq_throttle_check, NULL, 0); 779 780 if (!chip->restore) 781 goto out; 782 783 chip->restore = false; 784 for_each_cpu(cpu, &mask) { 785 int index; 786 struct cpufreq_policy policy; 787 788 cpufreq_get_policy(&policy, cpu); 789 index = cpufreq_table_find_index_c(&policy, policy.cur); 790 powernv_cpufreq_target_index(&policy, index); 791 cpumask_andnot(&mask, &mask, policy.cpus); 792 } 793 out: 794 put_online_cpus(); 795 } 796 797 static int powernv_cpufreq_occ_msg(struct notifier_block *nb, 798 unsigned long msg_type, void *_msg) 799 { 800 struct opal_msg *msg = _msg; 801 struct opal_occ_msg omsg; 802 int i; 803 804 if (msg_type != OPAL_MSG_OCC) 805 return 0; 806 807 omsg.type = be64_to_cpu(msg->params[0]); 808 809 switch (omsg.type) { 810 case OCC_RESET: 811 occ_reset = true; 812 pr_info("OCC (On Chip Controller - enforces hard thermal/power limits) Resetting\n"); 813 /* 814 * powernv_cpufreq_throttle_check() is called in 815 * target() callback which can detect the throttle state 816 * for governors like ondemand. 817 * But static governors will not call target() often thus 818 * report throttling here. 819 */ 820 if (!throttled) { 821 throttled = true; 822 pr_warn("CPU frequency is throttled for duration\n"); 823 } 824 825 break; 826 case OCC_LOAD: 827 pr_info("OCC Loading, CPU frequency is throttled until OCC is started\n"); 828 break; 829 case OCC_THROTTLE: 830 omsg.chip = be64_to_cpu(msg->params[1]); 831 omsg.throttle_status = be64_to_cpu(msg->params[2]); 832 833 if (occ_reset) { 834 occ_reset = false; 835 throttled = false; 836 pr_info("OCC Active, CPU frequency is no longer throttled\n"); 837 838 for (i = 0; i < nr_chips; i++) { 839 chips[i].restore = true; 840 schedule_work(&chips[i].throttle); 841 } 842 843 return 0; 844 } 845 846 for (i = 0; i < nr_chips; i++) 847 if (chips[i].id == omsg.chip) 848 break; 849 850 if (omsg.throttle_status >= 0 && 851 omsg.throttle_status <= OCC_MAX_THROTTLE_STATUS) { 852 chips[i].throttle_reason = omsg.throttle_status; 853 chips[i].reason[omsg.throttle_status]++; 854 } 855 856 if (!omsg.throttle_status) 857 chips[i].restore = true; 858 859 schedule_work(&chips[i].throttle); 860 } 861 return 0; 862 } 863 864 static struct notifier_block powernv_cpufreq_opal_nb = { 865 .notifier_call = powernv_cpufreq_occ_msg, 866 .next = NULL, 867 .priority = 0, 868 }; 869 870 static void powernv_cpufreq_stop_cpu(struct cpufreq_policy *policy) 871 { 872 struct powernv_smp_call_data freq_data; 873 struct global_pstate_info *gpstates = policy->driver_data; 874 875 freq_data.pstate_id = idx_to_pstate(powernv_pstate_info.min); 876 freq_data.gpstate_id = idx_to_pstate(powernv_pstate_info.min); 877 smp_call_function_single(policy->cpu, set_pstate, &freq_data, 1); 878 del_timer_sync(&gpstates->timer); 879 } 880 881 static struct cpufreq_driver powernv_cpufreq_driver = { 882 .name = "powernv-cpufreq", 883 .flags = CPUFREQ_CONST_LOOPS, 884 .init = powernv_cpufreq_cpu_init, 885 .exit = powernv_cpufreq_cpu_exit, 886 .verify = cpufreq_generic_frequency_table_verify, 887 .target_index = powernv_cpufreq_target_index, 888 .get = powernv_cpufreq_get, 889 .stop_cpu = powernv_cpufreq_stop_cpu, 890 .attr = powernv_cpu_freq_attr, 891 }; 892 893 static int init_chip_info(void) 894 { 895 unsigned int chip[256]; 896 unsigned int cpu, i; 897 unsigned int prev_chip_id = UINT_MAX; 898 899 for_each_possible_cpu(cpu) { 900 unsigned int id = cpu_to_chip_id(cpu); 901 902 if (prev_chip_id != id) { 903 prev_chip_id = id; 904 chip[nr_chips++] = id; 905 } 906 } 907 908 chips = kcalloc(nr_chips, sizeof(struct chip), GFP_KERNEL); 909 if (!chips) 910 return -ENOMEM; 911 912 for (i = 0; i < nr_chips; i++) { 913 chips[i].id = chip[i]; 914 cpumask_copy(&chips[i].mask, cpumask_of_node(chip[i])); 915 INIT_WORK(&chips[i].throttle, powernv_cpufreq_work_fn); 916 for_each_cpu(cpu, &chips[i].mask) 917 per_cpu(chip_info, cpu) = &chips[i]; 918 } 919 920 return 0; 921 } 922 923 static inline void clean_chip_info(void) 924 { 925 kfree(chips); 926 } 927 928 static inline void unregister_all_notifiers(void) 929 { 930 opal_message_notifier_unregister(OPAL_MSG_OCC, 931 &powernv_cpufreq_opal_nb); 932 unregister_reboot_notifier(&powernv_cpufreq_reboot_nb); 933 } 934 935 static int __init powernv_cpufreq_init(void) 936 { 937 int rc = 0; 938 939 /* Don't probe on pseries (guest) platforms */ 940 if (!firmware_has_feature(FW_FEATURE_OPAL)) 941 return -ENODEV; 942 943 /* Discover pstates from device tree and init */ 944 rc = init_powernv_pstates(); 945 if (rc) 946 goto out; 947 948 /* Populate chip info */ 949 rc = init_chip_info(); 950 if (rc) 951 goto out; 952 953 register_reboot_notifier(&powernv_cpufreq_reboot_nb); 954 opal_message_notifier_register(OPAL_MSG_OCC, &powernv_cpufreq_opal_nb); 955 956 rc = cpufreq_register_driver(&powernv_cpufreq_driver); 957 if (!rc) 958 return 0; 959 960 pr_info("Failed to register the cpufreq driver (%d)\n", rc); 961 unregister_all_notifiers(); 962 clean_chip_info(); 963 out: 964 pr_info("Platform driver disabled. System does not support PState control\n"); 965 return rc; 966 } 967 module_init(powernv_cpufreq_init); 968 969 static void __exit powernv_cpufreq_exit(void) 970 { 971 cpufreq_unregister_driver(&powernv_cpufreq_driver); 972 unregister_all_notifiers(); 973 clean_chip_info(); 974 } 975 module_exit(powernv_cpufreq_exit); 976 977 MODULE_LICENSE("GPL"); 978 MODULE_AUTHOR("Vaidyanathan Srinivasan <svaidy at linux.vnet.ibm.com>"); 979