drivers/cpufreq/powernv-cpufreq.c

   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 #define LPSTATE_SHIFT           48
  46 #define GPSTATE_SHIFT           56
  47 #define GET_LPSTATE(x)          (((x) >> LPSTATE_SHIFT) & 0xFF)
  48 #define GET_GPSTATE(x)          (((x) >> GPSTATE_SHIFT) & 0xFF)
  49
  50 #define MAX_RAMP_DOWN_TIME                              5120
  51 /*
  52  * On an idle system we want the global pstate to ramp-down from max value to
  53  * min over a span of ~5 secs. Also we want it to initially ramp-down slowly and
  54  * then ramp-down rapidly later on.
  55  *
  56  * This gives a percentage rampdown for time elapsed in milliseconds.
  57  * ramp_down_percentage = ((ms * ms) >> 18)
  58  *                      ~= 3.8 * (sec * sec)
  59  *
  60  * At 0 ms      ramp_down_percent = 0
  61  * At 5120 ms   ramp_down_percent = 100
  62  */
  63 #define ramp_down_percent(time)         ((time * time) >> 18)
  64
  65 /* Interval after which the timer is queued to bring down global pstate */
  66 #define GPSTATE_TIMER_INTERVAL                          2000
  67
  68 /**
  69  * struct global_pstate_info -  Per policy data structure to maintain history of
  70  *                              global pstates
  71  * @highest_lpstate_idx:        The local pstate index from which we are
  72  *                              ramping down
  73  * @elapsed_time:               Time in ms spent in ramping down from
  74  *                              highest_lpstate_idx
  75  * @last_sampled_time:          Time from boot in ms when global pstates were
  76  *                              last set
  77  * @last_lpstate_idx,           Last set value of local pstate and global
  78  * last_gpstate_idx             pstate in terms of cpufreq table index
  79  * @timer:                      Is used for ramping down if cpu goes idle for
  80  *                              a long time with global pstate held high
  81  * @gpstate_lock:               A spinlock to maintain synchronization between
  82  *                              routines called by the timer handler and
  83  *                              governer's target_index calls
  84  */
  85 struct global_pstate_info {
  86         int highest_lpstate_idx;
  87         unsigned int elapsed_time;
  88         unsigned int last_sampled_time;
  89         int last_lpstate_idx;
  90         int last_gpstate_idx;
  91         spinlock_t gpstate_lock;
  92         struct timer_list timer;
  93         struct cpufreq_policy *policy;
  94 };
  95
  96 static struct cpufreq_frequency_table powernv_freqs[POWERNV_MAX_PSTATES+1];
  97 static bool rebooting, throttled, occ_reset;
  98
  99 static const char * const throttle_reason[] = {
 100         "No throttling",
 101         "Power Cap",
 102         "Processor Over Temperature",
 103         "Power Supply Failure",
 104         "Over Current",
 105         "OCC Reset"
 106 };
 107
 108 enum throttle_reason_type {
 109         NO_THROTTLE = 0,
 110         POWERCAP,
 111         CPU_OVERTEMP,
 112         POWER_SUPPLY_FAILURE,
 113         OVERCURRENT,
 114         OCC_RESET_THROTTLE,
 115         OCC_MAX_REASON
 116 };
 117
 118 static struct chip {
 119         unsigned int id;
 120         bool throttled;
 121         bool restore;
 122         u8 throttle_reason;
 123         cpumask_t mask;
 124         struct work_struct throttle;
 125         int throttle_turbo;
 126         int throttle_sub_turbo;
 127         int reason[OCC_MAX_REASON];
 128 } *chips;
 129
 130 static int nr_chips;
 131 static DEFINE_PER_CPU(struct chip *, chip_info);
 132
 133 /*
 134  * Note:
 135  * The set of pstates consists of contiguous integers.
 136  * powernv_pstate_info stores the index of the frequency table for
 137  * max, min and nominal frequencies. It also stores number of
 138  * available frequencies.
 139  *
 140  * powernv_pstate_info.nominal indicates the index to the highest
 141  * non-turbo frequency.
 142  */
 143 static struct powernv_pstate_info {
 144         unsigned int min;
 145         unsigned int max;
 146         unsigned int nominal;
 147         unsigned int nr_pstates;
 148         bool wof_enabled;
 149 } powernv_pstate_info;
 150
 151 /* Use following macros for conversions between pstate_id and index */
 152 static inline int idx_to_pstate(unsigned int i)
 153 {
 154         if (unlikely(i >= powernv_pstate_info.nr_pstates)) {
 155                 pr_warn_once("index %u is out of bound\n", i);
 156                 return powernv_freqs[powernv_pstate_info.nominal].driver_data;
 157         }
 158
 159         return powernv_freqs[i].driver_data;
 160 }
 161
 162 static inline unsigned int pstate_to_idx(int pstate)
 163 {
 164         int min = powernv_freqs[powernv_pstate_info.min].driver_data;
 165         int max = powernv_freqs[powernv_pstate_info.max].driver_data;
 166
 167         if (min > 0) {
 168                 if (unlikely((pstate < max) || (pstate > min))) {
 169                         pr_warn_once("pstate %d is out of bound\n", pstate);
 170                         return powernv_pstate_info.nominal;
 171                 }
 172         } else {
 173                 if (unlikely((pstate > max) || (pstate < min))) {
 174                         pr_warn_once("pstate %d is out of bound\n", pstate);
 175                         return powernv_pstate_info.nominal;
 176                 }
 177         }
 178         /*
 179          * abs() is deliberately used so that is works with
 180          * both monotonically increasing and decreasing
 181          * pstate values
 182          */
 183         return abs(pstate - idx_to_pstate(powernv_pstate_info.max));
 184 }
 185
 186 static inline void reset_gpstates(struct cpufreq_policy *policy)
 187 {
 188         struct global_pstate_info *gpstates = policy->driver_data;
 189
 190         gpstates->highest_lpstate_idx = 0;
 191         gpstates->elapsed_time = 0;
 192         gpstates->last_sampled_time = 0;
 193         gpstates->last_lpstate_idx = 0;
 194         gpstates->last_gpstate_idx = 0;
 195 }
 196
 197 /*
 198  * Initialize the freq table based on data obtained
 199  * from the firmware passed via device-tree
 200  */
 201 static int init_powernv_pstates(void)
 202 {
 203         struct device_node *power_mgt;
 204         int i, nr_pstates = 0;
 205         const __be32 *pstate_ids, *pstate_freqs;
 206         u32 len_ids, len_freqs;
 207         u32 pstate_min, pstate_max, pstate_nominal;
 208         u32 pstate_turbo, pstate_ultra_turbo;
 209
 210         power_mgt = of_find_node_by_path("/ibm,opal/power-mgt");
 211         if (!power_mgt) {
 212                 pr_warn("power-mgt node not found\n");
 213                 return -ENODEV;
 214         }
 215
 216         if (of_property_read_u32(power_mgt, "ibm,pstate-min", &pstate_min)) {
 217                 pr_warn("ibm,pstate-min node not found\n");
 218                 return -ENODEV;
 219         }
 220
 221         if (of_property_read_u32(power_mgt, "ibm,pstate-max", &pstate_max)) {
 222                 pr_warn("ibm,pstate-max node not found\n");
 223                 return -ENODEV;
 224         }
 225
 226         if (of_property_read_u32(power_mgt, "ibm,pstate-nominal",
 227                                  &pstate_nominal)) {
 228                 pr_warn("ibm,pstate-nominal not found\n");
 229                 return -ENODEV;
 230         }
 231
 232         if (of_property_read_u32(power_mgt, "ibm,pstate-ultra-turbo",
 233                                  &pstate_ultra_turbo)) {
 234                 powernv_pstate_info.wof_enabled = false;
 235                 goto next;
 236         }
 237
 238         if (of_property_read_u32(power_mgt, "ibm,pstate-turbo",
 239                                  &pstate_turbo)) {
 240                 powernv_pstate_info.wof_enabled = false;
 241                 goto next;
 242         }
 243
 244         if (pstate_turbo == pstate_ultra_turbo)
 245                 powernv_pstate_info.wof_enabled = false;
 246         else
 247                 powernv_pstate_info.wof_enabled = true;
 248
 249 next:
 250         pr_info("cpufreq pstate min %d nominal %d max %d\n", pstate_min,
 251                 pstate_nominal, pstate_max);
 252         pr_info("Workload Optimized Frequency is %s in the platform\n",
 253                 (powernv_pstate_info.wof_enabled) ? "enabled" : "disabled");
 254
 255         pstate_ids = of_get_property(power_mgt, "ibm,pstate-ids", &len_ids);
 256         if (!pstate_ids) {
 257                 pr_warn("ibm,pstate-ids not found\n");
 258                 return -ENODEV;
 259         }
 260
 261         pstate_freqs = of_get_property(power_mgt, "ibm,pstate-frequencies-mhz",
 262                                       &len_freqs);
 263         if (!pstate_freqs) {
 264                 pr_warn("ibm,pstate-frequencies-mhz not found\n");
 265                 return -ENODEV;
 266         }
 267
 268         if (len_ids != len_freqs) {
 269                 pr_warn("Entries in ibm,pstate-ids and "
 270                         "ibm,pstate-frequencies-mhz does not match\n");
 271         }
 272
 273         nr_pstates = min(len_ids, len_freqs) / sizeof(u32);
 274         if (!nr_pstates) {
 275                 pr_warn("No PStates found\n");
 276                 return -ENODEV;
 277         }
 278
 279         powernv_pstate_info.nr_pstates = nr_pstates;
 280         pr_debug("NR PStates %d\n", nr_pstates);
 281         for (i = 0; i < nr_pstates; i++) {
 282                 u32 id = be32_to_cpu(pstate_ids[i]);
 283                 u32 freq = be32_to_cpu(pstate_freqs[i]);
 284
 285                 pr_debug("PState id %d freq %d MHz\n", id, freq);
 286                 powernv_freqs[i].frequency = freq * 1000; /* kHz */
 287                 powernv_freqs[i].driver_data = id;
 288
 289                 if (id == pstate_max)
 290                         powernv_pstate_info.max = i;
 291                 else if (id == pstate_nominal)
 292                         powernv_pstate_info.nominal = i;
 293                 else if (id == pstate_min)
 294                         powernv_pstate_info.min = i;
 295
 296                 if (powernv_pstate_info.wof_enabled && id == pstate_turbo) {
 297                         int j;
 298
 299                         for (j = i - 1; j >= (int)powernv_pstate_info.max; j--)
 300                                 powernv_freqs[j].flags = CPUFREQ_BOOST_FREQ;
 301                 }
 302         }
 303
 304         /* End of list marker entry */
 305         powernv_freqs[i].frequency = CPUFREQ_TABLE_END;
 306         return 0;
 307 }
 308
 309 /* Returns the CPU frequency corresponding to the pstate_id. */
 310 static unsigned int pstate_id_to_freq(int pstate_id)
 311 {
 312         int i;
 313
 314         i = pstate_to_idx(pstate_id);
 315         if (i >= powernv_pstate_info.nr_pstates || i < 0) {
 316                 pr_warn("PState id %d outside of PState table, "
 317                         "reporting nominal id %d instead\n",
 318                         pstate_id, idx_to_pstate(powernv_pstate_info.nominal));
 319                 i = powernv_pstate_info.nominal;
 320         }
 321
 322         return powernv_freqs[i].frequency;
 323 }
 324
 325 /*
 326  * cpuinfo_nominal_freq_show - Show the nominal CPU frequency as indicated by
 327  * the firmware
 328  */
 329 static ssize_t cpuinfo_nominal_freq_show(struct cpufreq_policy *policy,
 330                                         char *buf)
 331 {
 332         return sprintf(buf, "%u\n",
 333                 powernv_freqs[powernv_pstate_info.nominal].frequency);
 334 }
 335
 336 struct freq_attr cpufreq_freq_attr_cpuinfo_nominal_freq =
 337         __ATTR_RO(cpuinfo_nominal_freq);
 338
 339 #define SCALING_BOOST_FREQS_ATTR_INDEX          2
 340
 341 static struct freq_attr *powernv_cpu_freq_attr[] = {
 342         &cpufreq_freq_attr_scaling_available_freqs,
 343         &cpufreq_freq_attr_cpuinfo_nominal_freq,
 344         &cpufreq_freq_attr_scaling_boost_freqs,
 345         NULL,
 346 };
 347
 348 #define throttle_attr(name, member)                                     \
 349 static ssize_t name##_show(struct cpufreq_policy *policy, char *buf)    \
 350 {                                                                       \
 351         struct chip *chip = per_cpu(chip_info, policy->cpu);            \
 352                                                                         \
 353         return sprintf(buf, "%u\n", chip->member);                      \
 354 }                                                                       \
 355                                                                         \
 356 static struct freq_attr throttle_attr_##name = __ATTR_RO(name)          \
 357
 358 throttle_attr(unthrottle, reason[NO_THROTTLE]);
 359 throttle_attr(powercap, reason[POWERCAP]);
 360 throttle_attr(overtemp, reason[CPU_OVERTEMP]);
 361 throttle_attr(supply_fault, reason[POWER_SUPPLY_FAILURE]);
 362 throttle_attr(overcurrent, reason[OVERCURRENT]);
 363 throttle_attr(occ_reset, reason[OCC_RESET_THROTTLE]);
 364 throttle_attr(turbo_stat, throttle_turbo);
 365 throttle_attr(sub_turbo_stat, throttle_sub_turbo);
 366
 367 static struct attribute *throttle_attrs[] = {
 368         &throttle_attr_unthrottle.attr,
 369         &throttle_attr_powercap.attr,
 370         &throttle_attr_overtemp.attr,
 371         &throttle_attr_supply_fault.attr,
 372         &throttle_attr_overcurrent.attr,
 373         &throttle_attr_occ_reset.attr,
 374         &throttle_attr_turbo_stat.attr,
 375         &throttle_attr_sub_turbo_stat.attr,
 376         NULL,
 377 };
 378
 379 static const struct attribute_group throttle_attr_grp = {
 380         .name   = "throttle_stats",
 381         .attrs  = throttle_attrs,
 382 };
 383
 384 /* Helper routines */
 385
 386 /* Access helpers to power mgt SPR */
 387
 388 static inline unsigned long get_pmspr(unsigned long sprn)
 389 {
 390         switch (sprn) {
 391         case SPRN_PMCR:
 392                 return mfspr(SPRN_PMCR);
 393
 394         case SPRN_PMICR:
 395                 return mfspr(SPRN_PMICR);
 396
 397         case SPRN_PMSR:
 398                 return mfspr(SPRN_PMSR);
 399         }
 400         BUG();
 401 }
 402
 403 static inline void set_pmspr(unsigned long sprn, unsigned long val)
 404 {
 405         switch (sprn) {
 406         case SPRN_PMCR:
 407                 mtspr(SPRN_PMCR, val);
 408                 return;
 409
 410         case SPRN_PMICR:
 411                 mtspr(SPRN_PMICR, val);
 412                 return;
 413         }
 414         BUG();
 415 }
 416
 417 /*
 418  * Use objects of this type to query/update
 419  * pstates on a remote CPU via smp_call_function.
 420  */
 421 struct powernv_smp_call_data {
 422         unsigned int freq;
 423         int pstate_id;
 424         int gpstate_id;
 425 };
 426
 427 /*
 428  * powernv_read_cpu_freq: Reads the current frequency on this CPU.
 429  *
 430  * Called via smp_call_function.
 431  *
 432  * Note: The caller of the smp_call_function should pass an argument of
 433  * the type 'struct powernv_smp_call_data *' along with this function.
 434  *
 435  * The current frequency on this CPU will be returned via
 436  * ((struct powernv_smp_call_data *)arg)->freq;
 437  */
 438 static void powernv_read_cpu_freq(void *arg)
 439 {
 440         unsigned long pmspr_val;
 441         s8 local_pstate_id;
 442         struct powernv_smp_call_data *freq_data = arg;
 443
 444         pmspr_val = get_pmspr(SPRN_PMSR);
 445
 446         /*
 447          * The local pstate id corresponds bits 48..55 in the PMSR.
 448          * Note: Watch out for the sign!
 449          */
 450         local_pstate_id = (pmspr_val >> 48) & 0xFF;
 451         freq_data->pstate_id = local_pstate_id;
 452         freq_data->freq = pstate_id_to_freq(freq_data->pstate_id);
 453
 454         pr_debug("cpu %d pmsr %016lX pstate_id %d frequency %d kHz\n",
 455                 raw_smp_processor_id(), pmspr_val, freq_data->pstate_id,
 456                 freq_data->freq);
 457 }
 458
 459 /*
 460  * powernv_cpufreq_get: Returns the CPU frequency as reported by the
 461  * firmware for CPU 'cpu'. This value is reported through the sysfs
 462  * file cpuinfo_cur_freq.
 463  */
 464 static unsigned int powernv_cpufreq_get(unsigned int cpu)
 465 {
 466         struct powernv_smp_call_data freq_data;
 467
 468         smp_call_function_any(cpu_sibling_mask(cpu), powernv_read_cpu_freq,
 469                         &freq_data, 1);
 470
 471         return freq_data.freq;
 472 }
 473
 474 /*
 475  * set_pstate: Sets the pstate on this CPU.
 476  *
 477  * This is called via an smp_call_function.
 478  *
 479  * The caller must ensure that freq_data is of the type
 480  * (struct powernv_smp_call_data *) and the pstate_id which needs to be set
 481  * on this CPU should be present in freq_data->pstate_id.
 482  */
 483 static void set_pstate(void *data)
 484 {
 485         unsigned long val;
 486         struct powernv_smp_call_data *freq_data = data;
 487         unsigned long pstate_ul = freq_data->pstate_id;
 488         unsigned long gpstate_ul = freq_data->gpstate_id;
 489
 490         val = get_pmspr(SPRN_PMCR);
 491         val = val & 0x0000FFFFFFFFFFFFULL;
 492
 493         pstate_ul = pstate_ul & 0xFF;
 494         gpstate_ul = gpstate_ul & 0xFF;
 495
 496         /* Set both global(bits 56..63) and local(bits 48..55) PStates */
 497         val = val | (gpstate_ul << 56) | (pstate_ul << 48);
 498
 499         pr_debug("Setting cpu %d pmcr to %016lX\n",
 500                         raw_smp_processor_id(), val);
 501         set_pmspr(SPRN_PMCR, val);
 502 }
 503
 504 /*
 505  * get_nominal_index: Returns the index corresponding to the nominal
 506  * pstate in the cpufreq table
 507  */
 508 static inline unsigned int get_nominal_index(void)
 509 {
 510         return powernv_pstate_info.nominal;
 511 }
 512
 513 static void powernv_cpufreq_throttle_check(void *data)
 514 {
 515         struct chip *chip;
 516         unsigned int cpu = smp_processor_id();
 517         unsigned long pmsr;
 518         int pmsr_pmax;
 519         unsigned int pmsr_pmax_idx;
 520
 521         pmsr = get_pmspr(SPRN_PMSR);
 522         chip = this_cpu_read(chip_info);
 523
 524         /* Check for Pmax Capping */
 525         pmsr_pmax = (s8)PMSR_MAX(pmsr);
 526         pmsr_pmax_idx = pstate_to_idx(pmsr_pmax);
 527         if (pmsr_pmax_idx != powernv_pstate_info.max) {
 528                 if (chip->throttled)
 529                         goto next;
 530                 chip->throttled = true;
 531                 if (pmsr_pmax_idx > powernv_pstate_info.nominal) {
 532                         pr_warn_once("CPU %d on Chip %u has Pmax(%d) reduced below nominal frequency(%d)\n",
 533                                      cpu, chip->id, pmsr_pmax,
 534                                      idx_to_pstate(powernv_pstate_info.nominal));
 535                         chip->throttle_sub_turbo++;
 536                 } else {
 537                         chip->throttle_turbo++;
 538                 }
 539                 trace_powernv_throttle(chip->id,
 540                                       throttle_reason[chip->throttle_reason],
 541                                       pmsr_pmax);
 542         } else if (chip->throttled) {
 543                 chip->throttled = false;
 544                 trace_powernv_throttle(chip->id,
 545                                       throttle_reason[chip->throttle_reason],
 546                                       pmsr_pmax);
 547         }
 548
 549         /* Check if Psafe_mode_active is set in PMSR. */
 550 next:
 551         if (pmsr & PMSR_PSAFE_ENABLE) {
 552                 throttled = true;
 553                 pr_info("Pstate set to safe frequency\n");
 554         }
 555
 556         /* Check if SPR_EM_DISABLE is set in PMSR */
 557         if (pmsr & PMSR_SPR_EM_DISABLE) {
 558                 throttled = true;
 559                 pr_info("Frequency Control disabled from OS\n");
 560         }
 561
 562         if (throttled) {
 563                 pr_info("PMSR = %16lx\n", pmsr);
 564                 pr_warn("CPU Frequency could be throttled\n");
 565         }
 566 }
 567
 568 /**
 569  * calc_global_pstate - Calculate global pstate
 570  * @elapsed_time:               Elapsed time in milliseconds
 571  * @local_pstate_idx:           New local pstate
 572  * @highest_lpstate_idx:        pstate from which its ramping down
 573  *
 574  * Finds the appropriate global pstate based on the pstate from which its
 575  * ramping down and the time elapsed in ramping down. It follows a quadratic
 576  * equation which ensures that it reaches ramping down to pmin in 5sec.
 577  */
 578 static inline int calc_global_pstate(unsigned int elapsed_time,
 579                                      int highest_lpstate_idx,
 580                                      int local_pstate_idx)
 581 {
 582         int index_diff;
 583
 584         /*
 585          * Using ramp_down_percent we get the percentage of rampdown
 586          * that we are expecting to be dropping. Difference between
 587          * highest_lpstate_idx and powernv_pstate_info.min will give a absolute
 588          * number of how many pstates we will drop eventually by the end of
 589          * 5 seconds, then just scale it get the number pstates to be dropped.
 590          */
 591         index_diff =  ((int)ramp_down_percent(elapsed_time) *
 592                         (powernv_pstate_info.min - highest_lpstate_idx)) / 100;
 593
 594         /* Ensure that global pstate is >= to local pstate */
 595         if (highest_lpstate_idx + index_diff >= local_pstate_idx)
 596                 return local_pstate_idx;
 597         else
 598                 return highest_lpstate_idx + index_diff;
 599 }
 600
 601 static inline void  queue_gpstate_timer(struct global_pstate_info *gpstates)
 602 {
 603         unsigned int timer_interval;
 604
 605         /*
 606          * Setting up timer to fire after GPSTATE_TIMER_INTERVAL ms, But
 607          * if it exceeds MAX_RAMP_DOWN_TIME ms for ramp down time.
 608          * Set timer such that it fires exactly at MAX_RAMP_DOWN_TIME
 609          * seconds of ramp down time.
 610          */
 611         if ((gpstates->elapsed_time + GPSTATE_TIMER_INTERVAL)
 612              > MAX_RAMP_DOWN_TIME)
 613                 timer_interval = MAX_RAMP_DOWN_TIME - gpstates->elapsed_time;
 614         else
 615                 timer_interval = GPSTATE_TIMER_INTERVAL;
 616
 617         mod_timer(&gpstates->timer, jiffies + msecs_to_jiffies(timer_interval));
 618 }
 619
 620 /**
 621  * gpstate_timer_handler
 622  *
 623  * @data: pointer to cpufreq_policy on which timer was queued
 624  *
 625  * This handler brings down the global pstate closer to the local pstate
 626  * according quadratic equation. Queues a new timer if it is still not equal
 627  * to local pstate
 628  */
 629 void gpstate_timer_handler(struct timer_list *t)
 630 {
 631         struct global_pstate_info *gpstates = from_timer(gpstates, t, timer);
 632         struct cpufreq_policy *policy = gpstates->policy;
 633         int gpstate_idx, lpstate_idx;
 634         unsigned long val;
 635         unsigned int time_diff = jiffies_to_msecs(jiffies)
 636                                         - gpstates->last_sampled_time;
 637         struct powernv_smp_call_data freq_data;
 638
 639         if (!spin_trylock(&gpstates->gpstate_lock))
 640                 return;
 641
 642         /*
 643          * If PMCR was last updated was using fast_swtich then
 644          * We may have wrong in gpstate->last_lpstate_idx
 645          * value. Hence, read from PMCR to get correct data.
 646          */
 647         val = get_pmspr(SPRN_PMCR);
 648         freq_data.gpstate_id = (s8)GET_GPSTATE(val);
 649         freq_data.pstate_id = (s8)GET_LPSTATE(val);
 650         if (freq_data.gpstate_id  == freq_data.pstate_id) {
 651                 reset_gpstates(policy);
 652                 spin_unlock(&gpstates->gpstate_lock);
 653                 return;
 654         }
 655
 656         gpstates->last_sampled_time += time_diff;
 657         gpstates->elapsed_time += time_diff;
 658
 659         if (gpstates->elapsed_time > MAX_RAMP_DOWN_TIME) {
 660                 gpstate_idx = pstate_to_idx(freq_data.pstate_id);
 661                 lpstate_idx = gpstate_idx;
 662                 reset_gpstates(policy);
 663                 gpstates->highest_lpstate_idx = gpstate_idx;
 664         } else {
 665                 lpstate_idx = pstate_to_idx(freq_data.pstate_id);
 666                 gpstate_idx = calc_global_pstate(gpstates->elapsed_time,
 667                                                  gpstates->highest_lpstate_idx,
 668                                                  lpstate_idx);
 669         }
 670         freq_data.gpstate_id = idx_to_pstate(gpstate_idx);
 671         gpstates->last_gpstate_idx = gpstate_idx;
 672         gpstates->last_lpstate_idx = lpstate_idx;
 673         /*
 674          * If local pstate is equal to global pstate, rampdown is over
 675          * So timer is not required to be queued.
 676          */
 677         if (gpstate_idx != gpstates->last_lpstate_idx)
 678                 queue_gpstate_timer(gpstates);
 679
 680         spin_unlock(&gpstates->gpstate_lock);
 681
 682         /* Timer may get migrated to a different cpu on cpu hot unplug */
 683         smp_call_function_any(policy->cpus, set_pstate, &freq_data, 1);
 684 }
 685
 686 /*
 687  * powernv_cpufreq_target_index: Sets the frequency corresponding to
 688  * the cpufreq table entry indexed by new_index on the cpus in the
 689  * mask policy->cpus
 690  */
 691 static int powernv_cpufreq_target_index(struct cpufreq_policy *policy,
 692                                         unsigned int new_index)
 693 {
 694         struct powernv_smp_call_data freq_data;
 695         unsigned int cur_msec, gpstate_idx;
 696         struct global_pstate_info *gpstates = policy->driver_data;
 697
 698         if (unlikely(rebooting) && new_index != get_nominal_index())
 699                 return 0;
 700
 701         if (!throttled) {
 702                 /* we don't want to be preempted while
 703                  * checking if the CPU frequency has been throttled
 704                  */
 705                 preempt_disable();
 706                 powernv_cpufreq_throttle_check(NULL);
 707                 preempt_enable();
 708         }
 709
 710         cur_msec = jiffies_to_msecs(get_jiffies_64());
 711
 712         spin_lock(&gpstates->gpstate_lock);
 713         freq_data.pstate_id = idx_to_pstate(new_index);
 714
 715         if (!gpstates->last_sampled_time) {
 716                 gpstate_idx = new_index;
 717                 gpstates->highest_lpstate_idx = new_index;
 718                 goto gpstates_done;
 719         }
 720
 721         if (gpstates->last_gpstate_idx < new_index) {
 722                 gpstates->elapsed_time += cur_msec -
 723                                                  gpstates->last_sampled_time;
 724
 725                 /*
 726                  * If its has been ramping down for more than MAX_RAMP_DOWN_TIME
 727                  * we should be resetting all global pstate related data. Set it
 728                  * equal to local pstate to start fresh.
 729                  */
 730                 if (gpstates->elapsed_time > MAX_RAMP_DOWN_TIME) {
 731                         reset_gpstates(policy);
 732                         gpstates->highest_lpstate_idx = new_index;
 733                         gpstate_idx = new_index;
 734                 } else {
 735                 /* Elaspsed_time is less than 5 seconds, continue to rampdown */
 736                         gpstate_idx = calc_global_pstate(gpstates->elapsed_time,
 737                                                          gpstates->highest_lpstate_idx,
 738                                                          new_index);
 739                 }
 740         } else {
 741                 reset_gpstates(policy);
 742                 gpstates->highest_lpstate_idx = new_index;
 743                 gpstate_idx = new_index;
 744         }
 745
 746         /*
 747          * If local pstate is equal to global pstate, rampdown is over
 748          * So timer is not required to be queued.
 749          */
 750         if (gpstate_idx != new_index)
 751                 queue_gpstate_timer(gpstates);
 752         else
 753                 del_timer_sync(&gpstates->timer);
 754
 755 gpstates_done:
 756         freq_data.gpstate_id = idx_to_pstate(gpstate_idx);
 757         gpstates->last_sampled_time = cur_msec;
 758         gpstates->last_gpstate_idx = gpstate_idx;
 759         gpstates->last_lpstate_idx = new_index;
 760
 761         spin_unlock(&gpstates->gpstate_lock);
 762
 763         /*
 764          * Use smp_call_function to send IPI and execute the
 765          * mtspr on target CPU.  We could do that without IPI
 766          * if current CPU is within policy->cpus (core)
 767          */
 768         smp_call_function_any(policy->cpus, set_pstate, &freq_data, 1);
 769         return 0;
 770 }
 771
 772 static int powernv_cpufreq_cpu_init(struct cpufreq_policy *policy)
 773 {
 774         int base, i, ret;
 775         struct kernfs_node *kn;
 776         struct global_pstate_info *gpstates;
 777
 778         base = cpu_first_thread_sibling(policy->cpu);
 779
 780         for (i = 0; i < threads_per_core; i++)
 781                 cpumask_set_cpu(base + i, policy->cpus);
 782
 783         kn = kernfs_find_and_get(policy->kobj.sd, throttle_attr_grp.name);
 784         if (!kn) {
 785                 int ret;
 786
 787                 ret = sysfs_create_group(&policy->kobj, &throttle_attr_grp);
 788                 if (ret) {
 789                         pr_info("Failed to create throttle stats directory for cpu %d\n",
 790                                 policy->cpu);
 791                         return ret;
 792                 }
 793         } else {
 794                 kernfs_put(kn);
 795         }
 796
 797         gpstates =  kzalloc(sizeof(*gpstates), GFP_KERNEL);
 798         if (!gpstates)
 799                 return -ENOMEM;
 800
 801         policy->driver_data = gpstates;
 802
 803         /* initialize timer */
 804         gpstates->policy = policy;
 805         timer_setup(&gpstates->timer, gpstate_timer_handler,
 806                     TIMER_PINNED | TIMER_DEFERRABLE);
 807         gpstates->timer.expires = jiffies +
 808                                 msecs_to_jiffies(GPSTATE_TIMER_INTERVAL);
 809         spin_lock_init(&gpstates->gpstate_lock);
 810         ret = cpufreq_table_validate_and_show(policy, powernv_freqs);
 811
 812         if (ret < 0) {
 813                 kfree(policy->driver_data);
 814                 return ret;
 815         }
 816
 817         policy->fast_switch_possible = true;
 818         return ret;
 819 }
 820
 821 static int powernv_cpufreq_cpu_exit(struct cpufreq_policy *policy)
 822 {
 823         /* timer is deleted in cpufreq_cpu_stop() */
 824         kfree(policy->driver_data);
 825
 826         return 0;
 827 }
 828
 829 static int powernv_cpufreq_reboot_notifier(struct notifier_block *nb,
 830                                 unsigned long action, void *unused)
 831 {
 832         int cpu;
 833         struct cpufreq_policy cpu_policy;
 834
 835         rebooting = true;
 836         for_each_online_cpu(cpu) {
 837                 cpufreq_get_policy(&cpu_policy, cpu);
 838                 powernv_cpufreq_target_index(&cpu_policy, get_nominal_index());
 839         }
 840
 841         return NOTIFY_DONE;
 842 }
 843
 844 static struct notifier_block powernv_cpufreq_reboot_nb = {
 845         .notifier_call = powernv_cpufreq_reboot_notifier,
 846 };
 847
 848 void powernv_cpufreq_work_fn(struct work_struct *work)
 849 {
 850         struct chip *chip = container_of(work, struct chip, throttle);
 851         unsigned int cpu;
 852         cpumask_t mask;
 853
 854         get_online_cpus();
 855         cpumask_and(&mask, &chip->mask, cpu_online_mask);
 856         smp_call_function_any(&mask,
 857                               powernv_cpufreq_throttle_check, NULL, 0);
 858
 859         if (!chip->restore)
 860                 goto out;
 861
 862         chip->restore = false;
 863         for_each_cpu(cpu, &mask) {
 864                 int index;
 865                 struct cpufreq_policy policy;
 866
 867                 cpufreq_get_policy(&policy, cpu);
 868                 index = cpufreq_table_find_index_c(&policy, policy.cur);
 869                 powernv_cpufreq_target_index(&policy, index);
 870                 cpumask_andnot(&mask, &mask, policy.cpus);
 871         }
 872 out:
 873         put_online_cpus();
 874 }
 875
 876 static int powernv_cpufreq_occ_msg(struct notifier_block *nb,
 877                                    unsigned long msg_type, void *_msg)
 878 {
 879         struct opal_msg *msg = _msg;
 880         struct opal_occ_msg omsg;
 881         int i;
 882
 883         if (msg_type != OPAL_MSG_OCC)
 884                 return 0;
 885
 886         omsg.type = be64_to_cpu(msg->params[0]);
 887
 888         switch (omsg.type) {
 889         case OCC_RESET:
 890                 occ_reset = true;
 891                 pr_info("OCC (On Chip Controller - enforces hard thermal/power limits) Resetting\n");
 892                 /*
 893                  * powernv_cpufreq_throttle_check() is called in
 894                  * target() callback which can detect the throttle state
 895                  * for governors like ondemand.
 896                  * But static governors will not call target() often thus
 897                  * report throttling here.
 898                  */
 899                 if (!throttled) {
 900                         throttled = true;
 901                         pr_warn("CPU frequency is throttled for duration\n");
 902                 }
 903
 904                 break;
 905         case OCC_LOAD:
 906                 pr_info("OCC Loading, CPU frequency is throttled until OCC is started\n");
 907                 break;
 908         case OCC_THROTTLE:
 909                 omsg.chip = be64_to_cpu(msg->params[1]);
 910                 omsg.throttle_status = be64_to_cpu(msg->params[2]);
 911
 912                 if (occ_reset) {
 913                         occ_reset = false;
 914                         throttled = false;
 915                         pr_info("OCC Active, CPU frequency is no longer throttled\n");
 916
 917                         for (i = 0; i < nr_chips; i++) {
 918                                 chips[i].restore = true;
 919                                 schedule_work(&chips[i].throttle);
 920                         }
 921
 922                         return 0;
 923                 }
 924
 925                 for (i = 0; i < nr_chips; i++)
 926                         if (chips[i].id == omsg.chip)
 927                                 break;
 928
 929                 if (omsg.throttle_status >= 0 &&
 930                     omsg.throttle_status <= OCC_MAX_THROTTLE_STATUS) {
 931                         chips[i].throttle_reason = omsg.throttle_status;
 932                         chips[i].reason[omsg.throttle_status]++;
 933                 }
 934
 935                 if (!omsg.throttle_status)
 936                         chips[i].restore = true;
 937
 938                 schedule_work(&chips[i].throttle);
 939         }
 940         return 0;
 941 }
 942
 943 static struct notifier_block powernv_cpufreq_opal_nb = {
 944         .notifier_call  = powernv_cpufreq_occ_msg,
 945         .next           = NULL,
 946         .priority       = 0,
 947 };
 948
 949 static void powernv_cpufreq_stop_cpu(struct cpufreq_policy *policy)
 950 {
 951         struct powernv_smp_call_data freq_data;
 952         struct global_pstate_info *gpstates = policy->driver_data;
 953
 954         freq_data.pstate_id = idx_to_pstate(powernv_pstate_info.min);
 955         freq_data.gpstate_id = idx_to_pstate(powernv_pstate_info.min);
 956         smp_call_function_single(policy->cpu, set_pstate, &freq_data, 1);
 957         del_timer_sync(&gpstates->timer);
 958 }
 959
 960 static unsigned int powernv_fast_switch(struct cpufreq_policy *policy,
 961                                         unsigned int target_freq)
 962 {
 963         int index;
 964         struct powernv_smp_call_data freq_data;
 965
 966         index = cpufreq_table_find_index_dl(policy, target_freq);
 967         freq_data.pstate_id = powernv_freqs[index].driver_data;
 968         freq_data.gpstate_id = powernv_freqs[index].driver_data;
 969         set_pstate(&freq_data);
 970
 971         return powernv_freqs[index].frequency;
 972 }
 973
 974 static struct cpufreq_driver powernv_cpufreq_driver = {
 975         .name           = "powernv-cpufreq",
 976         .flags          = CPUFREQ_CONST_LOOPS,
 977         .init           = powernv_cpufreq_cpu_init,
 978         .exit           = powernv_cpufreq_cpu_exit,
 979         .verify         = cpufreq_generic_frequency_table_verify,
 980         .target_index   = powernv_cpufreq_target_index,
 981         .fast_switch    = powernv_fast_switch,
 982         .get            = powernv_cpufreq_get,
 983         .stop_cpu       = powernv_cpufreq_stop_cpu,
 984         .attr           = powernv_cpu_freq_attr,
 985 };
 986
 987 static int init_chip_info(void)
 988 {
 989         unsigned int chip[256];
 990         unsigned int cpu, i;
 991         unsigned int prev_chip_id = UINT_MAX;
 992
 993         for_each_possible_cpu(cpu) {
 994                 unsigned int id = cpu_to_chip_id(cpu);
 995
 996                 if (prev_chip_id != id) {
 997                         prev_chip_id = id;
 998                         chip[nr_chips++] = id;
 999                 }
1000         }
1001
1002         chips = kcalloc(nr_chips, sizeof(struct chip), GFP_KERNEL);
1003         if (!chips)
1004                 return -ENOMEM;
1005
1006         for (i = 0; i < nr_chips; i++) {
1007                 chips[i].id = chip[i];
1008                 cpumask_copy(&chips[i].mask, cpumask_of_node(chip[i]));
1009                 INIT_WORK(&chips[i].throttle, powernv_cpufreq_work_fn);
1010                 for_each_cpu(cpu, &chips[i].mask)
1011                         per_cpu(chip_info, cpu) =  &chips[i];
1012         }
1013
1014         return 0;
1015 }
1016
1017 static inline void clean_chip_info(void)
1018 {
1019         kfree(chips);
1020 }
1021
1022 static inline void unregister_all_notifiers(void)
1023 {
1024         opal_message_notifier_unregister(OPAL_MSG_OCC,
1025                                          &powernv_cpufreq_opal_nb);
1026         unregister_reboot_notifier(&powernv_cpufreq_reboot_nb);
1027 }
1028
1029 static int __init powernv_cpufreq_init(void)
1030 {
1031         int rc = 0;
1032
1033         /* Don't probe on pseries (guest) platforms */
1034         if (!firmware_has_feature(FW_FEATURE_OPAL))
1035                 return -ENODEV;
1036
1037         /* Discover pstates from device tree and init */
1038         rc = init_powernv_pstates();
1039         if (rc)
1040                 goto out;
1041
1042         /* Populate chip info */
1043         rc = init_chip_info();
1044         if (rc)
1045                 goto out;
1046
1047         register_reboot_notifier(&powernv_cpufreq_reboot_nb);
1048         opal_message_notifier_register(OPAL_MSG_OCC, &powernv_cpufreq_opal_nb);
1049
1050         if (powernv_pstate_info.wof_enabled)
1051                 powernv_cpufreq_driver.boost_enabled = true;
1052         else
1053                 powernv_cpu_freq_attr[SCALING_BOOST_FREQS_ATTR_INDEX] = NULL;
1054
1055         rc = cpufreq_register_driver(&powernv_cpufreq_driver);
1056         if (rc) {
1057                 pr_info("Failed to register the cpufreq driver (%d)\n", rc);
1058                 goto cleanup_notifiers;
1059         }
1060
1061         if (powernv_pstate_info.wof_enabled)
1062                 cpufreq_enable_boost_support();
1063
1064         return 0;
1065 cleanup_notifiers:
1066         unregister_all_notifiers();
1067         clean_chip_info();
1068 out:
1069         pr_info("Platform driver disabled. System does not support PState control\n");
1070         return rc;
1071 }
1072 module_init(powernv_cpufreq_init);
1073
1074 static void __exit powernv_cpufreq_exit(void)
1075 {
1076         cpufreq_unregister_driver(&powernv_cpufreq_driver);
1077         unregister_all_notifiers();
1078         clean_chip_info();
1079 }
1080 module_exit(powernv_cpufreq_exit);
1081
1082 MODULE_LICENSE("GPL");
1083 MODULE_AUTHOR("Vaidyanathan Srinivasan <svaidy at linux.vnet.ibm.com>");