drivers/cpufreq/powernv-cpufreq.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * POWERNV cpufreq driver for the IBM POWER processors
   4  *
   5  * (C) Copyright IBM 2014
   6  *
   7  * Author: Vaidyanathan Srinivasan <svaidy at linux.vnet.ibm.com>
   8  */
   9
  10 #define pr_fmt(fmt)     "powernv-cpufreq: " fmt
  11
  12 #include <linux/kernel.h>
  13 #include <linux/sysfs.h>
  14 #include <linux/cpumask.h>
  15 #include <linux/module.h>
  16 #include <linux/cpufreq.h>
  17 #include <linux/smp.h>
  18 #include <linux/of.h>
  19 #include <linux/reboot.h>
  20 #include <linux/slab.h>
  21 #include <linux/cpu.h>
  22 #include <linux/hashtable.h>
  23 #include <trace/events/power.h>
  24
  25 #include <asm/cputhreads.h>
  26 #include <asm/firmware.h>
  27 #include <asm/reg.h>
  28 #include <asm/smp.h> /* Required for cpu_sibling_mask() in UP configs */
  29 #include <asm/opal.h>
  30 #include <linux/timer.h>
  31
  32 #define POWERNV_MAX_PSTATES_ORDER  8
  33 #define POWERNV_MAX_PSTATES     (1UL << (POWERNV_MAX_PSTATES_ORDER))
  34 #define PMSR_PSAFE_ENABLE       (1UL << 30)
  35 #define PMSR_SPR_EM_DISABLE     (1UL << 31)
  36 #define MAX_PSTATE_SHIFT        32
  37 #define LPSTATE_SHIFT           48
  38 #define GPSTATE_SHIFT           56
  39
  40 #define MAX_RAMP_DOWN_TIME                              5120
  41 /*
  42  * On an idle system we want the global pstate to ramp-down from max value to
  43  * min over a span of ~5 secs. Also we want it to initially ramp-down slowly and
  44  * then ramp-down rapidly later on.
  45  *
  46  * This gives a percentage rampdown for time elapsed in milliseconds.
  47  * ramp_down_percentage = ((ms * ms) >> 18)
  48  *                      ~= 3.8 * (sec * sec)
  49  *
  50  * At 0 ms      ramp_down_percent = 0
  51  * At 5120 ms   ramp_down_percent = 100
  52  */
  53 #define ramp_down_percent(time)         ((time * time) >> 18)
  54
  55 /* Interval after which the timer is queued to bring down global pstate */
  56 #define GPSTATE_TIMER_INTERVAL                          2000
  57
  58 /**
  59  * struct global_pstate_info -  Per policy data structure to maintain history of
  60  *                              global pstates
  61  * @highest_lpstate_idx:        The local pstate index from which we are
  62  *                              ramping down
  63  * @elapsed_time:               Time in ms spent in ramping down from
  64  *                              highest_lpstate_idx
  65  * @last_sampled_time:          Time from boot in ms when global pstates were
  66  *                              last set
  67  * @last_lpstate_idx:           Last set value of local pstate and global
  68  * @last_gpstate_idx:           pstate in terms of cpufreq table index
  69  * @timer:                      Is used for ramping down if cpu goes idle for
  70  *                              a long time with global pstate held high
  71  * @gpstate_lock:               A spinlock to maintain synchronization between
  72  *                              routines called by the timer handler and
  73  *                              governer's target_index calls
  74  * @policy:                     Associated CPUFreq policy
  75  */
  76 struct global_pstate_info {
  77         int highest_lpstate_idx;
  78         unsigned int elapsed_time;
  79         unsigned int last_sampled_time;
  80         int last_lpstate_idx;
  81         int last_gpstate_idx;
  82         spinlock_t gpstate_lock;
  83         struct timer_list timer;
  84         struct cpufreq_policy *policy;
  85 };
  86
  87 static struct cpufreq_frequency_table powernv_freqs[POWERNV_MAX_PSTATES+1];
  88
  89 static DEFINE_HASHTABLE(pstate_revmap, POWERNV_MAX_PSTATES_ORDER);
  90 /**
  91  * struct pstate_idx_revmap_data: Entry in the hashmap pstate_revmap
  92  *                                indexed by a function of pstate id.
  93  *
  94  * @pstate_id: pstate id for this entry.
  95  *
  96  * @cpufreq_table_idx: Index into the powernv_freqs
  97  *                     cpufreq_frequency_table for frequency
  98  *                     corresponding to pstate_id.
  99  *
 100  * @hentry: hlist_node that hooks this entry into the pstate_revmap
 101  *          hashtable
 102  */
 103 struct pstate_idx_revmap_data {
 104         u8 pstate_id;
 105         unsigned int cpufreq_table_idx;
 106         struct hlist_node hentry;
 107 };
 108
 109 static bool rebooting, throttled, occ_reset;
 110
 111 static const char * const throttle_reason[] = {
 112         "No throttling",
 113         "Power Cap",
 114         "Processor Over Temperature",
 115         "Power Supply Failure",
 116         "Over Current",
 117         "OCC Reset"
 118 };
 119
 120 enum throttle_reason_type {
 121         NO_THROTTLE = 0,
 122         POWERCAP,
 123         CPU_OVERTEMP,
 124         POWER_SUPPLY_FAILURE,
 125         OVERCURRENT,
 126         OCC_RESET_THROTTLE,
 127         OCC_MAX_REASON
 128 };
 129
 130 static struct chip {
 131         unsigned int id;
 132         bool throttled;
 133         bool restore;
 134         u8 throttle_reason;
 135         cpumask_t mask;
 136         struct work_struct throttle;
 137         int throttle_turbo;
 138         int throttle_sub_turbo;
 139         int reason[OCC_MAX_REASON];
 140 } *chips;
 141
 142 static int nr_chips;
 143 static DEFINE_PER_CPU(struct chip *, chip_info);
 144
 145 /*
 146  * Note:
 147  * The set of pstates consists of contiguous integers.
 148  * powernv_pstate_info stores the index of the frequency table for
 149  * max, min and nominal frequencies. It also stores number of
 150  * available frequencies.
 151  *
 152  * powernv_pstate_info.nominal indicates the index to the highest
 153  * non-turbo frequency.
 154  */
 155 static struct powernv_pstate_info {
 156         unsigned int min;
 157         unsigned int max;
 158         unsigned int nominal;
 159         unsigned int nr_pstates;
 160         bool wof_enabled;
 161 } powernv_pstate_info;
 162
 163 static inline u8 extract_pstate(u64 pmsr_val, unsigned int shift)
 164 {
 165         return ((pmsr_val >> shift) & 0xFF);
 166 }
 167
 168 #define extract_local_pstate(x) extract_pstate(x, LPSTATE_SHIFT)
 169 #define extract_global_pstate(x) extract_pstate(x, GPSTATE_SHIFT)
 170 #define extract_max_pstate(x)  extract_pstate(x, MAX_PSTATE_SHIFT)
 171
 172 /* Use following functions for conversions between pstate_id and index */
 173
 174 /*
 175  * idx_to_pstate : Returns the pstate id corresponding to the
 176  *                 frequency in the cpufreq frequency table
 177  *                 powernv_freqs indexed by @i.
 178  *
 179  *                 If @i is out of bound, this will return the pstate
 180  *                 corresponding to the nominal frequency.
 181  */
 182 static inline u8 idx_to_pstate(unsigned int i)
 183 {
 184         if (unlikely(i >= powernv_pstate_info.nr_pstates)) {
 185                 pr_warn_once("idx_to_pstate: index %u is out of bound\n", i);
 186                 return powernv_freqs[powernv_pstate_info.nominal].driver_data;
 187         }
 188
 189         return powernv_freqs[i].driver_data;
 190 }
 191
 192 /*
 193  * pstate_to_idx : Returns the index in the cpufreq frequencytable
 194  *                 powernv_freqs for the frequency whose corresponding
 195  *                 pstate id is @pstate.
 196  *
 197  *                 If no frequency corresponding to @pstate is found,
 198  *                 this will return the index of the nominal
 199  *                 frequency.
 200  */
 201 static unsigned int pstate_to_idx(u8 pstate)
 202 {
 203         unsigned int key = pstate % POWERNV_MAX_PSTATES;
 204         struct pstate_idx_revmap_data *revmap_data;
 205
 206         hash_for_each_possible(pstate_revmap, revmap_data, hentry, key) {
 207                 if (revmap_data->pstate_id == pstate)
 208                         return revmap_data->cpufreq_table_idx;
 209         }
 210
 211         pr_warn_once("pstate_to_idx: pstate 0x%x not found\n", pstate);
 212         return powernv_pstate_info.nominal;
 213 }
 214
 215 static inline void reset_gpstates(struct cpufreq_policy *policy)
 216 {
 217         struct global_pstate_info *gpstates = policy->driver_data;
 218
 219         gpstates->highest_lpstate_idx = 0;
 220         gpstates->elapsed_time = 0;
 221         gpstates->last_sampled_time = 0;
 222         gpstates->last_lpstate_idx = 0;
 223         gpstates->last_gpstate_idx = 0;
 224 }
 225
 226 /*
 227  * Initialize the freq table based on data obtained
 228  * from the firmware passed via device-tree
 229  */
 230 static int init_powernv_pstates(void)
 231 {
 232         struct device_node *power_mgt;
 233         int i, nr_pstates = 0;
 234         const __be32 *pstate_ids, *pstate_freqs;
 235         u32 len_ids, len_freqs;
 236         u32 pstate_min, pstate_max, pstate_nominal;
 237         u32 pstate_turbo, pstate_ultra_turbo;
 238         int rc = -ENODEV;
 239
 240         power_mgt = of_find_node_by_path("/ibm,opal/power-mgt");
 241         if (!power_mgt) {
 242                 pr_warn("power-mgt node not found\n");
 243                 return -ENODEV;
 244         }
 245
 246         if (of_property_read_u32(power_mgt, "ibm,pstate-min", &pstate_min)) {
 247                 pr_warn("ibm,pstate-min node not found\n");
 248                 goto out;
 249         }
 250
 251         if (of_property_read_u32(power_mgt, "ibm,pstate-max", &pstate_max)) {
 252                 pr_warn("ibm,pstate-max node not found\n");
 253                 goto out;
 254         }
 255
 256         if (of_property_read_u32(power_mgt, "ibm,pstate-nominal",
 257                                  &pstate_nominal)) {
 258                 pr_warn("ibm,pstate-nominal not found\n");
 259                 goto out;
 260         }
 261
 262         if (of_property_read_u32(power_mgt, "ibm,pstate-ultra-turbo",
 263                                  &pstate_ultra_turbo)) {
 264                 powernv_pstate_info.wof_enabled = false;
 265                 goto next;
 266         }
 267
 268         if (of_property_read_u32(power_mgt, "ibm,pstate-turbo",
 269                                  &pstate_turbo)) {
 270                 powernv_pstate_info.wof_enabled = false;
 271                 goto next;
 272         }
 273
 274         if (pstate_turbo == pstate_ultra_turbo)
 275                 powernv_pstate_info.wof_enabled = false;
 276         else
 277                 powernv_pstate_info.wof_enabled = true;
 278
 279 next:
 280         pr_info("cpufreq pstate min 0x%x nominal 0x%x max 0x%x\n", pstate_min,
 281                 pstate_nominal, pstate_max);
 282         pr_info("Workload Optimized Frequency is %s in the platform\n",
 283                 (powernv_pstate_info.wof_enabled) ? "enabled" : "disabled");
 284
 285         pstate_ids = of_get_property(power_mgt, "ibm,pstate-ids", &len_ids);
 286         if (!pstate_ids) {
 287                 pr_warn("ibm,pstate-ids not found\n");
 288                 goto out;
 289         }
 290
 291         pstate_freqs = of_get_property(power_mgt, "ibm,pstate-frequencies-mhz",
 292                                       &len_freqs);
 293         if (!pstate_freqs) {
 294                 pr_warn("ibm,pstate-frequencies-mhz not found\n");
 295                 goto out;
 296         }
 297
 298         if (len_ids != len_freqs) {
 299                 pr_warn("Entries in ibm,pstate-ids and "
 300                         "ibm,pstate-frequencies-mhz does not match\n");
 301         }
 302
 303         nr_pstates = min(len_ids, len_freqs) / sizeof(u32);
 304         if (!nr_pstates) {
 305                 pr_warn("No PStates found\n");
 306                 goto out;
 307         }
 308
 309         powernv_pstate_info.nr_pstates = nr_pstates;
 310         pr_debug("NR PStates %d\n", nr_pstates);
 311
 312         for (i = 0; i < nr_pstates; i++) {
 313                 u32 id = be32_to_cpu(pstate_ids[i]);
 314                 u32 freq = be32_to_cpu(pstate_freqs[i]);
 315                 struct pstate_idx_revmap_data *revmap_data;
 316                 unsigned int key;
 317
 318                 pr_debug("PState id %d freq %d MHz\n", id, freq);
 319                 powernv_freqs[i].frequency = freq * 1000; /* kHz */
 320                 powernv_freqs[i].driver_data = id & 0xFF;
 321
 322                 revmap_data = kmalloc(sizeof(*revmap_data), GFP_KERNEL);
 323                 if (!revmap_data) {
 324                         rc = -ENOMEM;
 325                         goto out;
 326                 }
 327
 328                 revmap_data->pstate_id = id & 0xFF;
 329                 revmap_data->cpufreq_table_idx = i;
 330                 key = (revmap_data->pstate_id) % POWERNV_MAX_PSTATES;
 331                 hash_add(pstate_revmap, &revmap_data->hentry, key);
 332
 333                 if (id == pstate_max)
 334                         powernv_pstate_info.max = i;
 335                 if (id == pstate_nominal)
 336                         powernv_pstate_info.nominal = i;
 337                 if (id == pstate_min)
 338                         powernv_pstate_info.min = i;
 339
 340                 if (powernv_pstate_info.wof_enabled && id == pstate_turbo) {
 341                         int j;
 342
 343                         for (j = i - 1; j >= (int)powernv_pstate_info.max; j--)
 344                                 powernv_freqs[j].flags = CPUFREQ_BOOST_FREQ;
 345                 }
 346         }
 347
 348         /* End of list marker entry */
 349         powernv_freqs[i].frequency = CPUFREQ_TABLE_END;
 350
 351         of_node_put(power_mgt);
 352         return 0;
 353 out:
 354         of_node_put(power_mgt);
 355         return rc;
 356 }
 357
 358 /* Returns the CPU frequency corresponding to the pstate_id. */
 359 static unsigned int pstate_id_to_freq(u8 pstate_id)
 360 {
 361         int i;
 362
 363         i = pstate_to_idx(pstate_id);
 364         if (i >= powernv_pstate_info.nr_pstates || i < 0) {
 365                 pr_warn("PState id 0x%x outside of PState table, reporting nominal id 0x%x instead\n",
 366                         pstate_id, idx_to_pstate(powernv_pstate_info.nominal));
 367                 i = powernv_pstate_info.nominal;
 368         }
 369
 370         return powernv_freqs[i].frequency;
 371 }
 372
 373 /*
 374  * cpuinfo_nominal_freq_show - Show the nominal CPU frequency as indicated by
 375  * the firmware
 376  */
 377 static ssize_t cpuinfo_nominal_freq_show(struct cpufreq_policy *policy,
 378                                         char *buf)
 379 {
 380         return sprintf(buf, "%u\n",
 381                 powernv_freqs[powernv_pstate_info.nominal].frequency);
 382 }
 383
 384 static struct freq_attr cpufreq_freq_attr_cpuinfo_nominal_freq =
 385         __ATTR_RO(cpuinfo_nominal_freq);
 386
 387 #define SCALING_BOOST_FREQS_ATTR_INDEX          2
 388
 389 static struct freq_attr *powernv_cpu_freq_attr[] = {
 390         &cpufreq_freq_attr_scaling_available_freqs,
 391         &cpufreq_freq_attr_cpuinfo_nominal_freq,
 392         &cpufreq_freq_attr_scaling_boost_freqs,
 393         NULL,
 394 };
 395
 396 #define throttle_attr(name, member)                                     \
 397 static ssize_t name##_show(struct cpufreq_policy *policy, char *buf)    \
 398 {                                                                       \
 399         struct chip *chip = per_cpu(chip_info, policy->cpu);            \
 400                                                                         \
 401         return sprintf(buf, "%u\n", chip->member);                      \
 402 }                                                                       \
 403                                                                         \
 404 static struct freq_attr throttle_attr_##name = __ATTR_RO(name)          \
 405
 406 throttle_attr(unthrottle, reason[NO_THROTTLE]);
 407 throttle_attr(powercap, reason[POWERCAP]);
 408 throttle_attr(overtemp, reason[CPU_OVERTEMP]);
 409 throttle_attr(supply_fault, reason[POWER_SUPPLY_FAILURE]);
 410 throttle_attr(overcurrent, reason[OVERCURRENT]);
 411 throttle_attr(occ_reset, reason[OCC_RESET_THROTTLE]);
 412 throttle_attr(turbo_stat, throttle_turbo);
 413 throttle_attr(sub_turbo_stat, throttle_sub_turbo);
 414
 415 static struct attribute *throttle_attrs[] = {
 416         &throttle_attr_unthrottle.attr,
 417         &throttle_attr_powercap.attr,
 418         &throttle_attr_overtemp.attr,
 419         &throttle_attr_supply_fault.attr,
 420         &throttle_attr_overcurrent.attr,
 421         &throttle_attr_occ_reset.attr,
 422         &throttle_attr_turbo_stat.attr,
 423         &throttle_attr_sub_turbo_stat.attr,
 424         NULL,
 425 };
 426
 427 static const struct attribute_group throttle_attr_grp = {
 428         .name   = "throttle_stats",
 429         .attrs  = throttle_attrs,
 430 };
 431
 432 /* Helper routines */
 433
 434 /* Access helpers to power mgt SPR */
 435
 436 static inline unsigned long get_pmspr(unsigned long sprn)
 437 {
 438         switch (sprn) {
 439         case SPRN_PMCR:
 440                 return mfspr(SPRN_PMCR);
 441
 442         case SPRN_PMICR:
 443                 return mfspr(SPRN_PMICR);
 444
 445         case SPRN_PMSR:
 446                 return mfspr(SPRN_PMSR);
 447         }
 448         BUG();
 449 }
 450
 451 static inline void set_pmspr(unsigned long sprn, unsigned long val)
 452 {
 453         switch (sprn) {
 454         case SPRN_PMCR:
 455                 mtspr(SPRN_PMCR, val);
 456                 return;
 457
 458         case SPRN_PMICR:
 459                 mtspr(SPRN_PMICR, val);
 460                 return;
 461         }
 462         BUG();
 463 }
 464
 465 /*
 466  * Use objects of this type to query/update
 467  * pstates on a remote CPU via smp_call_function.
 468  */
 469 struct powernv_smp_call_data {
 470         unsigned int freq;
 471         u8 pstate_id;
 472         u8 gpstate_id;
 473 };
 474
 475 /*
 476  * powernv_read_cpu_freq: Reads the current frequency on this CPU.
 477  *
 478  * Called via smp_call_function.
 479  *
 480  * Note: The caller of the smp_call_function should pass an argument of
 481  * the type 'struct powernv_smp_call_data *' along with this function.
 482  *
 483  * The current frequency on this CPU will be returned via
 484  * ((struct powernv_smp_call_data *)arg)->freq;
 485  */
 486 static void powernv_read_cpu_freq(void *arg)
 487 {
 488         unsigned long pmspr_val;
 489         struct powernv_smp_call_data *freq_data = arg;
 490
 491         pmspr_val = get_pmspr(SPRN_PMSR);
 492         freq_data->pstate_id = extract_local_pstate(pmspr_val);
 493         freq_data->freq = pstate_id_to_freq(freq_data->pstate_id);
 494
 495         pr_debug("cpu %d pmsr %016lX pstate_id 0x%x frequency %d kHz\n",
 496                  raw_smp_processor_id(), pmspr_val, freq_data->pstate_id,
 497                  freq_data->freq);
 498 }
 499
 500 /*
 501  * powernv_cpufreq_get: Returns the CPU frequency as reported by the
 502  * firmware for CPU 'cpu'. This value is reported through the sysfs
 503  * file cpuinfo_cur_freq.
 504  */
 505 static unsigned int powernv_cpufreq_get(unsigned int cpu)
 506 {
 507         struct powernv_smp_call_data freq_data;
 508
 509         smp_call_function_any(cpu_sibling_mask(cpu), powernv_read_cpu_freq,
 510                         &freq_data, 1);
 511
 512         return freq_data.freq;
 513 }
 514
 515 /*
 516  * set_pstate: Sets the pstate on this CPU.
 517  *
 518  * This is called via an smp_call_function.
 519  *
 520  * The caller must ensure that freq_data is of the type
 521  * (struct powernv_smp_call_data *) and the pstate_id which needs to be set
 522  * on this CPU should be present in freq_data->pstate_id.
 523  */
 524 static void set_pstate(void *data)
 525 {
 526         unsigned long val;
 527         struct powernv_smp_call_data *freq_data = data;
 528         unsigned long pstate_ul = freq_data->pstate_id;
 529         unsigned long gpstate_ul = freq_data->gpstate_id;
 530
 531         val = get_pmspr(SPRN_PMCR);
 532         val = val & 0x0000FFFFFFFFFFFFULL;
 533
 534         pstate_ul = pstate_ul & 0xFF;
 535         gpstate_ul = gpstate_ul & 0xFF;
 536
 537         /* Set both global(bits 56..63) and local(bits 48..55) PStates */
 538         val = val | (gpstate_ul << 56) | (pstate_ul << 48);
 539
 540         pr_debug("Setting cpu %d pmcr to %016lX\n",
 541                         raw_smp_processor_id(), val);
 542         set_pmspr(SPRN_PMCR, val);
 543 }
 544
 545 /*
 546  * get_nominal_index: Returns the index corresponding to the nominal
 547  * pstate in the cpufreq table
 548  */
 549 static inline unsigned int get_nominal_index(void)
 550 {
 551         return powernv_pstate_info.nominal;
 552 }
 553
 554 static void powernv_cpufreq_throttle_check(void *data)
 555 {
 556         struct chip *chip;
 557         unsigned int cpu = smp_processor_id();
 558         unsigned long pmsr;
 559         u8 pmsr_pmax;
 560         unsigned int pmsr_pmax_idx;
 561
 562         pmsr = get_pmspr(SPRN_PMSR);
 563         chip = this_cpu_read(chip_info);
 564
 565         /* Check for Pmax Capping */
 566         pmsr_pmax = extract_max_pstate(pmsr);
 567         pmsr_pmax_idx = pstate_to_idx(pmsr_pmax);
 568         if (pmsr_pmax_idx != powernv_pstate_info.max) {
 569                 if (chip->throttled)
 570                         goto next;
 571                 chip->throttled = true;
 572                 if (pmsr_pmax_idx > powernv_pstate_info.nominal) {
 573                         pr_warn_once("CPU %d on Chip %u has Pmax(0x%x) reduced below that of nominal frequency(0x%x)\n",
 574                                      cpu, chip->id, pmsr_pmax,
 575                                      idx_to_pstate(powernv_pstate_info.nominal));
 576                         chip->throttle_sub_turbo++;
 577                 } else {
 578                         chip->throttle_turbo++;
 579                 }
 580                 trace_powernv_throttle(chip->id,
 581                                       throttle_reason[chip->throttle_reason],
 582                                       pmsr_pmax);
 583         } else if (chip->throttled) {
 584                 chip->throttled = false;
 585                 trace_powernv_throttle(chip->id,
 586                                       throttle_reason[chip->throttle_reason],
 587                                       pmsr_pmax);
 588         }
 589
 590         /* Check if Psafe_mode_active is set in PMSR. */
 591 next:
 592         if (pmsr & PMSR_PSAFE_ENABLE) {
 593                 throttled = true;
 594                 pr_info("Pstate set to safe frequency\n");
 595         }
 596
 597         /* Check if SPR_EM_DISABLE is set in PMSR */
 598         if (pmsr & PMSR_SPR_EM_DISABLE) {
 599                 throttled = true;
 600                 pr_info("Frequency Control disabled from OS\n");
 601         }
 602
 603         if (throttled) {
 604                 pr_info("PMSR = %16lx\n", pmsr);
 605                 pr_warn("CPU Frequency could be throttled\n");
 606         }
 607 }
 608
 609 /**
 610  * calc_global_pstate - Calculate global pstate
 611  * @elapsed_time:               Elapsed time in milliseconds
 612  * @local_pstate_idx:           New local pstate
 613  * @highest_lpstate_idx:        pstate from which its ramping down
 614  *
 615  * Finds the appropriate global pstate based on the pstate from which its
 616  * ramping down and the time elapsed in ramping down. It follows a quadratic
 617  * equation which ensures that it reaches ramping down to pmin in 5sec.
 618  */
 619 static inline int calc_global_pstate(unsigned int elapsed_time,
 620                                      int highest_lpstate_idx,
 621                                      int local_pstate_idx)
 622 {
 623         int index_diff;
 624
 625         /*
 626          * Using ramp_down_percent we get the percentage of rampdown
 627          * that we are expecting to be dropping. Difference between
 628          * highest_lpstate_idx and powernv_pstate_info.min will give a absolute
 629          * number of how many pstates we will drop eventually by the end of
 630          * 5 seconds, then just scale it get the number pstates to be dropped.
 631          */
 632         index_diff =  ((int)ramp_down_percent(elapsed_time) *
 633                         (powernv_pstate_info.min - highest_lpstate_idx)) / 100;
 634
 635         /* Ensure that global pstate is >= to local pstate */
 636         if (highest_lpstate_idx + index_diff >= local_pstate_idx)
 637                 return local_pstate_idx;
 638         else
 639                 return highest_lpstate_idx + index_diff;
 640 }
 641
 642 static inline void  queue_gpstate_timer(struct global_pstate_info *gpstates)
 643 {
 644         unsigned int timer_interval;
 645
 646         /*
 647          * Setting up timer to fire after GPSTATE_TIMER_INTERVAL ms, But
 648          * if it exceeds MAX_RAMP_DOWN_TIME ms for ramp down time.
 649          * Set timer such that it fires exactly at MAX_RAMP_DOWN_TIME
 650          * seconds of ramp down time.
 651          */
 652         if ((gpstates->elapsed_time + GPSTATE_TIMER_INTERVAL)
 653              > MAX_RAMP_DOWN_TIME)
 654                 timer_interval = MAX_RAMP_DOWN_TIME - gpstates->elapsed_time;
 655         else
 656                 timer_interval = GPSTATE_TIMER_INTERVAL;
 657
 658         mod_timer(&gpstates->timer, jiffies + msecs_to_jiffies(timer_interval));
 659 }
 660
 661 /**
 662  * gpstate_timer_handler
 663  *
 664  * @t: Timer context used to fetch global pstate info struct
 665  *
 666  * This handler brings down the global pstate closer to the local pstate
 667  * according quadratic equation. Queues a new timer if it is still not equal
 668  * to local pstate
 669  */
 670 static void gpstate_timer_handler(struct timer_list *t)
 671 {
 672         struct global_pstate_info *gpstates = from_timer(gpstates, t, timer);
 673         struct cpufreq_policy *policy = gpstates->policy;
 674         int gpstate_idx, lpstate_idx;
 675         unsigned long val;
 676         unsigned int time_diff = jiffies_to_msecs(jiffies)
 677                                         - gpstates->last_sampled_time;
 678         struct powernv_smp_call_data freq_data;
 679
 680         if (!spin_trylock(&gpstates->gpstate_lock))
 681                 return;
 682         /*
 683          * If the timer has migrated to the different cpu then bring
 684          * it back to one of the policy->cpus
 685          */
 686         if (!cpumask_test_cpu(raw_smp_processor_id(), policy->cpus)) {
 687                 gpstates->timer.expires = jiffies + msecs_to_jiffies(1);
 688                 add_timer_on(&gpstates->timer, cpumask_first(policy->cpus));
 689                 spin_unlock(&gpstates->gpstate_lock);
 690                 return;
 691         }
 692
 693         /*
 694          * If PMCR was last updated was using fast_swtich then
 695          * We may have wrong in gpstate->last_lpstate_idx
 696          * value. Hence, read from PMCR to get correct data.
 697          */
 698         val = get_pmspr(SPRN_PMCR);
 699         freq_data.gpstate_id = extract_global_pstate(val);
 700         freq_data.pstate_id = extract_local_pstate(val);
 701         if (freq_data.gpstate_id  == freq_data.pstate_id) {
 702                 reset_gpstates(policy);
 703                 spin_unlock(&gpstates->gpstate_lock);
 704                 return;
 705         }
 706
 707         gpstates->last_sampled_time += time_diff;
 708         gpstates->elapsed_time += time_diff;
 709
 710         if (gpstates->elapsed_time > MAX_RAMP_DOWN_TIME) {
 711                 gpstate_idx = pstate_to_idx(freq_data.pstate_id);
 712                 lpstate_idx = gpstate_idx;
 713                 reset_gpstates(policy);
 714                 gpstates->highest_lpstate_idx = gpstate_idx;
 715         } else {
 716                 lpstate_idx = pstate_to_idx(freq_data.pstate_id);
 717                 gpstate_idx = calc_global_pstate(gpstates->elapsed_time,
 718                                                  gpstates->highest_lpstate_idx,
 719                                                  lpstate_idx);
 720         }
 721         freq_data.gpstate_id = idx_to_pstate(gpstate_idx);
 722         gpstates->last_gpstate_idx = gpstate_idx;
 723         gpstates->last_lpstate_idx = lpstate_idx;
 724         /*
 725          * If local pstate is equal to global pstate, rampdown is over
 726          * So timer is not required to be queued.
 727          */
 728         if (gpstate_idx != gpstates->last_lpstate_idx)
 729                 queue_gpstate_timer(gpstates);
 730
 731         set_pstate(&freq_data);
 732         spin_unlock(&gpstates->gpstate_lock);
 733 }
 734
 735 /*
 736  * powernv_cpufreq_target_index: Sets the frequency corresponding to
 737  * the cpufreq table entry indexed by new_index on the cpus in the
 738  * mask policy->cpus
 739  */
 740 static int powernv_cpufreq_target_index(struct cpufreq_policy *policy,
 741                                         unsigned int new_index)
 742 {
 743         struct powernv_smp_call_data freq_data;
 744         unsigned int cur_msec, gpstate_idx;
 745         struct global_pstate_info *gpstates = policy->driver_data;
 746
 747         if (unlikely(rebooting) && new_index != get_nominal_index())
 748                 return 0;
 749
 750         if (!throttled) {
 751                 /* we don't want to be preempted while
 752                  * checking if the CPU frequency has been throttled
 753                  */
 754                 preempt_disable();
 755                 powernv_cpufreq_throttle_check(NULL);
 756                 preempt_enable();
 757         }
 758
 759         cur_msec = jiffies_to_msecs(get_jiffies_64());
 760
 761         freq_data.pstate_id = idx_to_pstate(new_index);
 762         if (!gpstates) {
 763                 freq_data.gpstate_id = freq_data.pstate_id;
 764                 goto no_gpstate;
 765         }
 766
 767         spin_lock(&gpstates->gpstate_lock);
 768
 769         if (!gpstates->last_sampled_time) {
 770                 gpstate_idx = new_index;
 771                 gpstates->highest_lpstate_idx = new_index;
 772                 goto gpstates_done;
 773         }
 774
 775         if (gpstates->last_gpstate_idx < new_index) {
 776                 gpstates->elapsed_time += cur_msec -
 777                                                  gpstates->last_sampled_time;
 778
 779                 /*
 780                  * If its has been ramping down for more than MAX_RAMP_DOWN_TIME
 781                  * we should be resetting all global pstate related data. Set it
 782                  * equal to local pstate to start fresh.
 783                  */
 784                 if (gpstates->elapsed_time > MAX_RAMP_DOWN_TIME) {
 785                         reset_gpstates(policy);
 786                         gpstates->highest_lpstate_idx = new_index;
 787                         gpstate_idx = new_index;
 788                 } else {
 789                 /* Elaspsed_time is less than 5 seconds, continue to rampdown */
 790                         gpstate_idx = calc_global_pstate(gpstates->elapsed_time,
 791                                                          gpstates->highest_lpstate_idx,
 792                                                          new_index);
 793                 }
 794         } else {
 795                 reset_gpstates(policy);
 796                 gpstates->highest_lpstate_idx = new_index;
 797                 gpstate_idx = new_index;
 798         }
 799
 800         /*
 801          * If local pstate is equal to global pstate, rampdown is over
 802          * So timer is not required to be queued.
 803          */
 804         if (gpstate_idx != new_index)
 805                 queue_gpstate_timer(gpstates);
 806         else
 807                 del_timer_sync(&gpstates->timer);
 808
 809 gpstates_done:
 810         freq_data.gpstate_id = idx_to_pstate(gpstate_idx);
 811         gpstates->last_sampled_time = cur_msec;
 812         gpstates->last_gpstate_idx = gpstate_idx;
 813         gpstates->last_lpstate_idx = new_index;
 814
 815         spin_unlock(&gpstates->gpstate_lock);
 816
 817 no_gpstate:
 818         /*
 819          * Use smp_call_function to send IPI and execute the
 820          * mtspr on target CPU.  We could do that without IPI
 821          * if current CPU is within policy->cpus (core)
 822          */
 823         smp_call_function_any(policy->cpus, set_pstate, &freq_data, 1);
 824         return 0;
 825 }
 826
 827 static int powernv_cpufreq_cpu_init(struct cpufreq_policy *policy)
 828 {
 829         int base, i;
 830         struct kernfs_node *kn;
 831         struct global_pstate_info *gpstates;
 832
 833         base = cpu_first_thread_sibling(policy->cpu);
 834
 835         for (i = 0; i < threads_per_core; i++)
 836                 cpumask_set_cpu(base + i, policy->cpus);
 837
 838         kn = kernfs_find_and_get(policy->kobj.sd, throttle_attr_grp.name);
 839         if (!kn) {
 840                 int ret;
 841
 842                 ret = sysfs_create_group(&policy->kobj, &throttle_attr_grp);
 843                 if (ret) {
 844                         pr_info("Failed to create throttle stats directory for cpu %d\n",
 845                                 policy->cpu);
 846                         return ret;
 847                 }
 848         } else {
 849                 kernfs_put(kn);
 850         }
 851
 852         policy->freq_table = powernv_freqs;
 853         policy->fast_switch_possible = true;
 854
 855         if (pvr_version_is(PVR_POWER9))
 856                 return 0;
 857
 858         /* Initialise Gpstate ramp-down timer only on POWER8 */
 859         gpstates =  kzalloc(sizeof(*gpstates), GFP_KERNEL);
 860         if (!gpstates)
 861                 return -ENOMEM;
 862
 863         policy->driver_data = gpstates;
 864
 865         /* initialize timer */
 866         gpstates->policy = policy;
 867         timer_setup(&gpstates->timer, gpstate_timer_handler,
 868                     TIMER_PINNED | TIMER_DEFERRABLE);
 869         gpstates->timer.expires = jiffies +
 870                                 msecs_to_jiffies(GPSTATE_TIMER_INTERVAL);
 871         spin_lock_init(&gpstates->gpstate_lock);
 872
 873         return 0;
 874 }
 875
 876 static int powernv_cpufreq_cpu_exit(struct cpufreq_policy *policy)
 877 {
 878         /* timer is deleted in cpufreq_cpu_stop() */
 879         kfree(policy->driver_data);
 880
 881         return 0;
 882 }
 883
 884 static int powernv_cpufreq_reboot_notifier(struct notifier_block *nb,
 885                                 unsigned long action, void *unused)
 886 {
 887         int cpu;
 888         struct cpufreq_policy cpu_policy;
 889
 890         rebooting = true;
 891         for_each_online_cpu(cpu) {
 892                 cpufreq_get_policy(&cpu_policy, cpu);
 893                 powernv_cpufreq_target_index(&cpu_policy, get_nominal_index());
 894         }
 895
 896         return NOTIFY_DONE;
 897 }
 898
 899 static struct notifier_block powernv_cpufreq_reboot_nb = {
 900         .notifier_call = powernv_cpufreq_reboot_notifier,
 901 };
 902
 903 static void powernv_cpufreq_work_fn(struct work_struct *work)
 904 {
 905         struct chip *chip = container_of(work, struct chip, throttle);
 906         struct cpufreq_policy *policy;
 907         unsigned int cpu;
 908         cpumask_t mask;
 909
 910         get_online_cpus();
 911         cpumask_and(&mask, &chip->mask, cpu_online_mask);
 912         smp_call_function_any(&mask,
 913                               powernv_cpufreq_throttle_check, NULL, 0);
 914
 915         if (!chip->restore)
 916                 goto out;
 917
 918         chip->restore = false;
 919         for_each_cpu(cpu, &mask) {
 920                 int index;
 921
 922                 policy = cpufreq_cpu_get(cpu);
 923                 if (!policy)
 924                         continue;
 925                 index = cpufreq_table_find_index_c(policy, policy->cur);
 926                 powernv_cpufreq_target_index(policy, index);
 927                 cpumask_andnot(&mask, &mask, policy->cpus);
 928                 cpufreq_cpu_put(policy);
 929         }
 930 out:
 931         put_online_cpus();
 932 }
 933
 934 static int powernv_cpufreq_occ_msg(struct notifier_block *nb,
 935                                    unsigned long msg_type, void *_msg)
 936 {
 937         struct opal_msg *msg = _msg;
 938         struct opal_occ_msg omsg;
 939         int i;
 940
 941         if (msg_type != OPAL_MSG_OCC)
 942                 return 0;
 943
 944         omsg.type = be64_to_cpu(msg->params[0]);
 945
 946         switch (omsg.type) {
 947         case OCC_RESET:
 948                 occ_reset = true;
 949                 pr_info("OCC (On Chip Controller - enforces hard thermal/power limits) Resetting\n");
 950                 /*
 951                  * powernv_cpufreq_throttle_check() is called in
 952                  * target() callback which can detect the throttle state
 953                  * for governors like ondemand.
 954                  * But static governors will not call target() often thus
 955                  * report throttling here.
 956                  */
 957                 if (!throttled) {
 958                         throttled = true;
 959                         pr_warn("CPU frequency is throttled for duration\n");
 960                 }
 961
 962                 break;
 963         case OCC_LOAD:
 964                 pr_info("OCC Loading, CPU frequency is throttled until OCC is started\n");
 965                 break;
 966         case OCC_THROTTLE:
 967                 omsg.chip = be64_to_cpu(msg->params[1]);
 968                 omsg.throttle_status = be64_to_cpu(msg->params[2]);
 969
 970                 if (occ_reset) {
 971                         occ_reset = false;
 972                         throttled = false;
 973                         pr_info("OCC Active, CPU frequency is no longer throttled\n");
 974
 975                         for (i = 0; i < nr_chips; i++) {
 976                                 chips[i].restore = true;
 977                                 schedule_work(&chips[i].throttle);
 978                         }
 979
 980                         return 0;
 981                 }
 982
 983                 for (i = 0; i < nr_chips; i++)
 984                         if (chips[i].id == omsg.chip)
 985                                 break;
 986
 987                 if (omsg.throttle_status >= 0 &&
 988                     omsg.throttle_status <= OCC_MAX_THROTTLE_STATUS) {
 989                         chips[i].throttle_reason = omsg.throttle_status;
 990                         chips[i].reason[omsg.throttle_status]++;
 991                 }
 992
 993                 if (!omsg.throttle_status)
 994                         chips[i].restore = true;
 995
 996                 schedule_work(&chips[i].throttle);
 997         }
 998         return 0;
 999 }
1000
1001 static struct notifier_block powernv_cpufreq_opal_nb = {
1002         .notifier_call  = powernv_cpufreq_occ_msg,
1003         .next           = NULL,
1004         .priority       = 0,
1005 };
1006
1007 static void powernv_cpufreq_stop_cpu(struct cpufreq_policy *policy)
1008 {
1009         struct powernv_smp_call_data freq_data;
1010         struct global_pstate_info *gpstates = policy->driver_data;
1011
1012         freq_data.pstate_id = idx_to_pstate(powernv_pstate_info.min);
1013         freq_data.gpstate_id = idx_to_pstate(powernv_pstate_info.min);
1014         smp_call_function_single(policy->cpu, set_pstate, &freq_data, 1);
1015         if (gpstates)
1016                 del_timer_sync(&gpstates->timer);
1017 }
1018
1019 static unsigned int powernv_fast_switch(struct cpufreq_policy *policy,
1020                                         unsigned int target_freq)
1021 {
1022         int index;
1023         struct powernv_smp_call_data freq_data;
1024
1025         index = cpufreq_table_find_index_dl(policy, target_freq);
1026         freq_data.pstate_id = powernv_freqs[index].driver_data;
1027         freq_data.gpstate_id = powernv_freqs[index].driver_data;
1028         set_pstate(&freq_data);
1029
1030         return powernv_freqs[index].frequency;
1031 }
1032
1033 static struct cpufreq_driver powernv_cpufreq_driver = {
1034         .name           = "powernv-cpufreq",
1035         .flags          = CPUFREQ_CONST_LOOPS,
1036         .init           = powernv_cpufreq_cpu_init,
1037         .exit           = powernv_cpufreq_cpu_exit,
1038         .verify         = cpufreq_generic_frequency_table_verify,
1039         .target_index   = powernv_cpufreq_target_index,
1040         .fast_switch    = powernv_fast_switch,
1041         .get            = powernv_cpufreq_get,
1042         .stop_cpu       = powernv_cpufreq_stop_cpu,
1043         .attr           = powernv_cpu_freq_attr,
1044 };
1045
1046 static int init_chip_info(void)
1047 {
1048         unsigned int *chip;
1049         unsigned int cpu, i;
1050         unsigned int prev_chip_id = UINT_MAX;
1051         int ret = 0;
1052
1053         chip = kcalloc(num_possible_cpus(), sizeof(*chip), GFP_KERNEL);
1054         if (!chip)
1055                 return -ENOMEM;
1056
1057         for_each_possible_cpu(cpu) {
1058                 unsigned int id = cpu_to_chip_id(cpu);
1059
1060                 if (prev_chip_id != id) {
1061                         prev_chip_id = id;
1062                         chip[nr_chips++] = id;
1063                 }
1064         }
1065
1066         chips = kcalloc(nr_chips, sizeof(struct chip), GFP_KERNEL);
1067         if (!chips) {
1068                 ret = -ENOMEM;
1069                 goto free_and_return;
1070         }
1071
1072         for (i = 0; i < nr_chips; i++) {
1073                 chips[i].id = chip[i];
1074                 cpumask_copy(&chips[i].mask, cpumask_of_node(chip[i]));
1075                 INIT_WORK(&chips[i].throttle, powernv_cpufreq_work_fn);
1076                 for_each_cpu(cpu, &chips[i].mask)
1077                         per_cpu(chip_info, cpu) =  &chips[i];
1078         }
1079
1080 free_and_return:
1081         kfree(chip);
1082         return ret;
1083 }
1084
1085 static inline void clean_chip_info(void)
1086 {
1087         int i;
1088
1089         /* flush any pending work items */
1090         if (chips)
1091                 for (i = 0; i < nr_chips; i++)
1092                         cancel_work_sync(&chips[i].throttle);
1093         kfree(chips);
1094 }
1095
1096 static inline void unregister_all_notifiers(void)
1097 {
1098         opal_message_notifier_unregister(OPAL_MSG_OCC,
1099                                          &powernv_cpufreq_opal_nb);
1100         unregister_reboot_notifier(&powernv_cpufreq_reboot_nb);
1101 }
1102
1103 static int __init powernv_cpufreq_init(void)
1104 {
1105         int rc = 0;
1106
1107         /* Don't probe on pseries (guest) platforms */
1108         if (!firmware_has_feature(FW_FEATURE_OPAL))
1109                 return -ENODEV;
1110
1111         /* Discover pstates from device tree and init */
1112         rc = init_powernv_pstates();
1113         if (rc)
1114                 goto out;
1115
1116         /* Populate chip info */
1117         rc = init_chip_info();
1118         if (rc)
1119                 goto out;
1120
1121         if (powernv_pstate_info.wof_enabled)
1122                 powernv_cpufreq_driver.boost_enabled = true;
1123         else
1124                 powernv_cpu_freq_attr[SCALING_BOOST_FREQS_ATTR_INDEX] = NULL;
1125
1126         rc = cpufreq_register_driver(&powernv_cpufreq_driver);
1127         if (rc) {
1128                 pr_info("Failed to register the cpufreq driver (%d)\n", rc);
1129                 goto cleanup;
1130         }
1131
1132         if (powernv_pstate_info.wof_enabled)
1133                 cpufreq_enable_boost_support();
1134
1135         register_reboot_notifier(&powernv_cpufreq_reboot_nb);
1136         opal_message_notifier_register(OPAL_MSG_OCC, &powernv_cpufreq_opal_nb);
1137
1138         return 0;
1139 cleanup:
1140         clean_chip_info();
1141 out:
1142         pr_info("Platform driver disabled. System does not support PState control\n");
1143         return rc;
1144 }
1145 module_init(powernv_cpufreq_init);
1146
1147 static void __exit powernv_cpufreq_exit(void)
1148 {
1149         cpufreq_unregister_driver(&powernv_cpufreq_driver);
1150         unregister_all_notifiers();
1151         clean_chip_info();
1152 }
1153 module_exit(powernv_cpufreq_exit);
1154
1155 MODULE_LICENSE("GPL");
1156 MODULE_AUTHOR("Vaidyanathan Srinivasan <svaidy at linux.vnet.ibm.com>");