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