drivers/cpuidle/cpuidle-powernv.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  cpuidle-powernv - idle state cpuidle driver.
   4  *  Adapted from drivers/cpuidle/cpuidle-pseries
   5  *
   6  */
   7
   8 #include <linux/kernel.h>
   9 #include <linux/module.h>
  10 #include <linux/init.h>
  11 #include <linux/moduleparam.h>
  12 #include <linux/cpuidle.h>
  13 #include <linux/cpu.h>
  14 #include <linux/notifier.h>
  15 #include <linux/clockchips.h>
  16 #include <linux/of.h>
  17 #include <linux/slab.h>
  18
  19 #include <asm/machdep.h>
  20 #include <asm/firmware.h>
  21 #include <asm/opal.h>
  22 #include <asm/runlatch.h>
  23 #include <asm/cpuidle.h>
  24
  25 /*
  26  * Expose only those Hardware idle states via the cpuidle framework
  27  * that have latency value below POWERNV_THRESHOLD_LATENCY_NS.
  28  */
  29 #define POWERNV_THRESHOLD_LATENCY_NS 200000
  30
  31 static struct cpuidle_driver powernv_idle_driver = {
  32         .name             = "powernv_idle",
  33         .owner            = THIS_MODULE,
  34 };
  35
  36 static int max_idle_state __read_mostly;
  37 static struct cpuidle_state *cpuidle_state_table __read_mostly;
  38
  39 struct stop_psscr_table {
  40         u64 val;
  41         u64 mask;
  42 };
  43
  44 static struct stop_psscr_table stop_psscr_table[CPUIDLE_STATE_MAX] __read_mostly;
  45
  46 static u64 default_snooze_timeout __read_mostly;
  47 static bool snooze_timeout_en __read_mostly;
  48
  49 static u64 get_snooze_timeout(struct cpuidle_device *dev,
  50                               struct cpuidle_driver *drv,
  51                               int index)
  52 {
  53         int i;
  54
  55         if (unlikely(!snooze_timeout_en))
  56                 return default_snooze_timeout;
  57
  58         for (i = index + 1; i < drv->state_count; i++) {
  59                 struct cpuidle_state *s = &drv->states[i];
  60                 struct cpuidle_state_usage *su = &dev->states_usage[i];
  61
  62                 if (s->disabled || su->disable)
  63                         continue;
  64
  65                 return s->target_residency * tb_ticks_per_usec;
  66         }
  67
  68         return default_snooze_timeout;
  69 }
  70
  71 static int snooze_loop(struct cpuidle_device *dev,
  72                         struct cpuidle_driver *drv,
  73                         int index)
  74 {
  75         u64 snooze_exit_time;
  76
  77         set_thread_flag(TIF_POLLING_NRFLAG);
  78
  79         local_irq_enable();
  80
  81         snooze_exit_time = get_tb() + get_snooze_timeout(dev, drv, index);
  82         ppc64_runlatch_off();
  83         HMT_very_low();
  84         while (!need_resched()) {
  85                 if (likely(snooze_timeout_en) && get_tb() > snooze_exit_time) {
  86                         /*
  87                          * Task has not woken up but we are exiting the polling
  88                          * loop anyway. Require a barrier after polling is
  89                          * cleared to order subsequent test of need_resched().
  90                          */
  91                         clear_thread_flag(TIF_POLLING_NRFLAG);
  92                         smp_mb();
  93                         break;
  94                 }
  95         }
  96
  97         HMT_medium();
  98         ppc64_runlatch_on();
  99         clear_thread_flag(TIF_POLLING_NRFLAG);
 100
 101         local_irq_disable();
 102
 103         return index;
 104 }
 105
 106 static int nap_loop(struct cpuidle_device *dev,
 107                         struct cpuidle_driver *drv,
 108                         int index)
 109 {
 110         power7_idle_type(PNV_THREAD_NAP);
 111
 112         return index;
 113 }
 114
 115 /* Register for fastsleep only in oneshot mode of broadcast */
 116 #ifdef CONFIG_TICK_ONESHOT
 117 static int fastsleep_loop(struct cpuidle_device *dev,
 118                                 struct cpuidle_driver *drv,
 119                                 int index)
 120 {
 121         unsigned long old_lpcr = mfspr(SPRN_LPCR);
 122         unsigned long new_lpcr;
 123
 124         if (unlikely(system_state < SYSTEM_RUNNING))
 125                 return index;
 126
 127         new_lpcr = old_lpcr;
 128         /* Do not exit powersave upon decrementer as we've setup the timer
 129          * offload.
 130          */
 131         new_lpcr &= ~LPCR_PECE1;
 132
 133         mtspr(SPRN_LPCR, new_lpcr);
 134
 135         power7_idle_type(PNV_THREAD_SLEEP);
 136
 137         mtspr(SPRN_LPCR, old_lpcr);
 138
 139         return index;
 140 }
 141 #endif
 142
 143 static int stop_loop(struct cpuidle_device *dev,
 144                      struct cpuidle_driver *drv,
 145                      int index)
 146 {
 147         power9_idle_type(stop_psscr_table[index].val,
 148                          stop_psscr_table[index].mask);
 149         return index;
 150 }
 151
 152 /*
 153  * States for dedicated partition case.
 154  */
 155 static struct cpuidle_state powernv_states[CPUIDLE_STATE_MAX] = {
 156         { /* Snooze */
 157                 .name = "snooze",
 158                 .desc = "snooze",
 159                 .exit_latency = 0,
 160                 .target_residency = 0,
 161                 .enter = snooze_loop },
 162 };
 163
 164 static int powernv_cpuidle_cpu_online(unsigned int cpu)
 165 {
 166         struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu);
 167
 168         if (dev && cpuidle_get_driver()) {
 169                 cpuidle_pause_and_lock();
 170                 cpuidle_enable_device(dev);
 171                 cpuidle_resume_and_unlock();
 172         }
 173         return 0;
 174 }
 175
 176 static int powernv_cpuidle_cpu_dead(unsigned int cpu)
 177 {
 178         struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu);
 179
 180         if (dev && cpuidle_get_driver()) {
 181                 cpuidle_pause_and_lock();
 182                 cpuidle_disable_device(dev);
 183                 cpuidle_resume_and_unlock();
 184         }
 185         return 0;
 186 }
 187
 188 /*
 189  * powernv_cpuidle_driver_init()
 190  */
 191 static int powernv_cpuidle_driver_init(void)
 192 {
 193         int idle_state;
 194         struct cpuidle_driver *drv = &powernv_idle_driver;
 195
 196         drv->state_count = 0;
 197
 198         for (idle_state = 0; idle_state < max_idle_state; ++idle_state) {
 199                 /* Is the state not enabled? */
 200                 if (cpuidle_state_table[idle_state].enter == NULL)
 201                         continue;
 202
 203                 drv->states[drv->state_count] = /* structure copy */
 204                         cpuidle_state_table[idle_state];
 205
 206                 drv->state_count += 1;
 207         }
 208
 209         /*
 210          * On the PowerNV platform cpu_present may be less than cpu_possible in
 211          * cases when firmware detects the CPU, but it is not available to the
 212          * OS.  If CONFIG_HOTPLUG_CPU=n, then such CPUs are not hotplugable at
 213          * run time and hence cpu_devices are not created for those CPUs by the
 214          * generic topology_init().
 215          *
 216          * drv->cpumask defaults to cpu_possible_mask in
 217          * __cpuidle_driver_init().  This breaks cpuidle on PowerNV where
 218          * cpu_devices are not created for CPUs in cpu_possible_mask that
 219          * cannot be hot-added later at run time.
 220          *
 221          * Trying cpuidle_register_device() on a CPU without a cpu_device is
 222          * incorrect, so pass a correct CPU mask to the generic cpuidle driver.
 223          */
 224
 225         drv->cpumask = (struct cpumask *)cpu_present_mask;
 226
 227         return 0;
 228 }
 229
 230 static inline void add_powernv_state(int index, const char *name,
 231                                      unsigned int flags,
 232                                      int (*idle_fn)(struct cpuidle_device *,
 233                                                     struct cpuidle_driver *,
 234                                                     int),
 235                                      unsigned int target_residency,
 236                                      unsigned int exit_latency,
 237                                      u64 psscr_val, u64 psscr_mask)
 238 {
 239         strlcpy(powernv_states[index].name, name, CPUIDLE_NAME_LEN);
 240         strlcpy(powernv_states[index].desc, name, CPUIDLE_NAME_LEN);
 241         powernv_states[index].flags = flags;
 242         powernv_states[index].target_residency = target_residency;
 243         powernv_states[index].exit_latency = exit_latency;
 244         powernv_states[index].enter = idle_fn;
 245         stop_psscr_table[index].val = psscr_val;
 246         stop_psscr_table[index].mask = psscr_mask;
 247 }
 248
 249 /*
 250  * Returns 0 if prop1_len == prop2_len. Else returns -1
 251  */
 252 static inline int validate_dt_prop_sizes(const char *prop1, int prop1_len,
 253                                          const char *prop2, int prop2_len)
 254 {
 255         if (prop1_len == prop2_len)
 256                 return 0;
 257
 258         pr_warn("cpuidle-powernv: array sizes don't match for %s and %s\n",
 259                 prop1, prop2);
 260         return -1;
 261 }
 262
 263 extern u32 pnv_get_supported_cpuidle_states(void);
 264 static int powernv_add_idle_states(void)
 265 {
 266         struct device_node *power_mgt;
 267         int nr_idle_states = 1; /* Snooze */
 268         int dt_idle_states, count;
 269         u32 latency_ns[CPUIDLE_STATE_MAX];
 270         u32 residency_ns[CPUIDLE_STATE_MAX];
 271         u32 flags[CPUIDLE_STATE_MAX];
 272         u64 psscr_val[CPUIDLE_STATE_MAX];
 273         u64 psscr_mask[CPUIDLE_STATE_MAX];
 274         const char *names[CPUIDLE_STATE_MAX];
 275         u32 has_stop_states = 0;
 276         int i, rc;
 277         u32 supported_flags = pnv_get_supported_cpuidle_states();
 278
 279
 280         /* Currently we have snooze statically defined */
 281
 282         power_mgt = of_find_node_by_path("/ibm,opal/power-mgt");
 283         if (!power_mgt) {
 284                 pr_warn("opal: PowerMgmt Node not found\n");
 285                 goto out;
 286         }
 287
 288         /* Read values of any property to determine the num of idle states */
 289         dt_idle_states = of_property_count_u32_elems(power_mgt, "ibm,cpu-idle-state-flags");
 290         if (dt_idle_states < 0) {
 291                 pr_warn("cpuidle-powernv: no idle states found in the DT\n");
 292                 goto out;
 293         }
 294
 295         count = of_property_count_u32_elems(power_mgt,
 296                                             "ibm,cpu-idle-state-latencies-ns");
 297
 298         if (validate_dt_prop_sizes("ibm,cpu-idle-state-flags", dt_idle_states,
 299                                    "ibm,cpu-idle-state-latencies-ns",
 300                                    count) != 0)
 301                 goto out;
 302
 303         count = of_property_count_strings(power_mgt,
 304                                           "ibm,cpu-idle-state-names");
 305         if (validate_dt_prop_sizes("ibm,cpu-idle-state-flags", dt_idle_states,
 306                                    "ibm,cpu-idle-state-names",
 307                                    count) != 0)
 308                 goto out;
 309
 310         /*
 311          * Since snooze is used as first idle state, max idle states allowed is
 312          * CPUIDLE_STATE_MAX -1
 313          */
 314         if (dt_idle_states > CPUIDLE_STATE_MAX - 1) {
 315                 pr_warn("cpuidle-powernv: discovered idle states more than allowed");
 316                 dt_idle_states = CPUIDLE_STATE_MAX - 1;
 317         }
 318
 319         if (of_property_read_u32_array(power_mgt,
 320                         "ibm,cpu-idle-state-flags", flags, dt_idle_states)) {
 321                 pr_warn("cpuidle-powernv : missing ibm,cpu-idle-state-flags in DT\n");
 322                 goto out;
 323         }
 324
 325         if (of_property_read_u32_array(power_mgt,
 326                 "ibm,cpu-idle-state-latencies-ns", latency_ns,
 327                 dt_idle_states)) {
 328                 pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-latencies-ns in DT\n");
 329                 goto out;
 330         }
 331         if (of_property_read_string_array(power_mgt,
 332                 "ibm,cpu-idle-state-names", names, dt_idle_states) < 0) {
 333                 pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-names in DT\n");
 334                 goto out;
 335         }
 336
 337         /*
 338          * If the idle states use stop instruction, probe for psscr values
 339          * and psscr mask which are necessary to specify required stop level.
 340          */
 341         has_stop_states = (flags[0] &
 342                            (OPAL_PM_STOP_INST_FAST | OPAL_PM_STOP_INST_DEEP));
 343         if (has_stop_states) {
 344                 count = of_property_count_u64_elems(power_mgt,
 345                                                     "ibm,cpu-idle-state-psscr");
 346                 if (validate_dt_prop_sizes("ibm,cpu-idle-state-flags",
 347                                            dt_idle_states,
 348                                            "ibm,cpu-idle-state-psscr",
 349                                            count) != 0)
 350                         goto out;
 351
 352                 count = of_property_count_u64_elems(power_mgt,
 353                                                     "ibm,cpu-idle-state-psscr-mask");
 354                 if (validate_dt_prop_sizes("ibm,cpu-idle-state-flags",
 355                                            dt_idle_states,
 356                                            "ibm,cpu-idle-state-psscr-mask",
 357                                            count) != 0)
 358                         goto out;
 359
 360                 if (of_property_read_u64_array(power_mgt,
 361                     "ibm,cpu-idle-state-psscr", psscr_val, dt_idle_states)) {
 362                         pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-psscr in DT\n");
 363                         goto out;
 364                 }
 365
 366                 if (of_property_read_u64_array(power_mgt,
 367                                                "ibm,cpu-idle-state-psscr-mask",
 368                                                 psscr_mask, dt_idle_states)) {
 369                         pr_warn("cpuidle-powernv:Missing ibm,cpu-idle-state-psscr-mask in DT\n");
 370                         goto out;
 371                 }
 372         }
 373
 374         count = of_property_count_u32_elems(power_mgt,
 375                                             "ibm,cpu-idle-state-residency-ns");
 376
 377         if (count < 0) {
 378                 rc = count;
 379         } else if (validate_dt_prop_sizes("ibm,cpu-idle-state-flags",
 380                                           dt_idle_states,
 381                                           "ibm,cpu-idle-state-residency-ns",
 382                                           count) != 0) {
 383                 goto out;
 384         } else {
 385                 rc = of_property_read_u32_array(power_mgt,
 386                                                 "ibm,cpu-idle-state-residency-ns",
 387                                                 residency_ns, dt_idle_states);
 388         }
 389
 390         for (i = 0; i < dt_idle_states; i++) {
 391                 unsigned int exit_latency, target_residency;
 392                 bool stops_timebase = false;
 393
 394                 /*
 395                  * Skip the platform idle state whose flag isn't in
 396                  * the supported_cpuidle_states flag mask.
 397                  */
 398                 if ((flags[i] & supported_flags) != flags[i])
 399                         continue;
 400                 /*
 401                  * If an idle state has exit latency beyond
 402                  * POWERNV_THRESHOLD_LATENCY_NS then don't use it
 403                  * in cpu-idle.
 404                  */
 405                 if (latency_ns[i] > POWERNV_THRESHOLD_LATENCY_NS)
 406                         continue;
 407                 /*
 408                  * Firmware passes residency and latency values in ns.
 409                  * cpuidle expects it in us.
 410                  */
 411                 exit_latency = DIV_ROUND_UP(latency_ns[i], 1000);
 412                 if (!rc)
 413                         target_residency = DIV_ROUND_UP(residency_ns[i], 1000);
 414                 else
 415                         target_residency = 0;
 416
 417                 if (has_stop_states) {
 418                         int err = validate_psscr_val_mask(&psscr_val[i],
 419                                                           &psscr_mask[i],
 420                                                           flags[i]);
 421                         if (err) {
 422                                 report_invalid_psscr_val(psscr_val[i], err);
 423                                 continue;
 424                         }
 425                 }
 426
 427                 if (flags[i] & OPAL_PM_TIMEBASE_STOP)
 428                         stops_timebase = true;
 429
 430                 /*
 431                  * For nap and fastsleep, use default target_residency
 432                  * values if f/w does not expose it.
 433                  */
 434                 if (flags[i] & OPAL_PM_NAP_ENABLED) {
 435                         if (!rc)
 436                                 target_residency = 100;
 437                         /* Add NAP state */
 438                         add_powernv_state(nr_idle_states, "Nap",
 439                                           CPUIDLE_FLAG_NONE, nap_loop,
 440                                           target_residency, exit_latency, 0, 0);
 441                 } else if (has_stop_states && !stops_timebase) {
 442                         add_powernv_state(nr_idle_states, names[i],
 443                                           CPUIDLE_FLAG_NONE, stop_loop,
 444                                           target_residency, exit_latency,
 445                                           psscr_val[i], psscr_mask[i]);
 446                 }
 447
 448                 /*
 449                  * All cpuidle states with CPUIDLE_FLAG_TIMER_STOP set must come
 450                  * within this config dependency check.
 451                  */
 452 #ifdef CONFIG_TICK_ONESHOT
 453                 else if (flags[i] & OPAL_PM_SLEEP_ENABLED ||
 454                          flags[i] & OPAL_PM_SLEEP_ENABLED_ER1) {
 455                         if (!rc)
 456                                 target_residency = 300000;
 457                         /* Add FASTSLEEP state */
 458                         add_powernv_state(nr_idle_states, "FastSleep",
 459                                           CPUIDLE_FLAG_TIMER_STOP,
 460                                           fastsleep_loop,
 461                                           target_residency, exit_latency, 0, 0);
 462                 } else if (has_stop_states && stops_timebase) {
 463                         add_powernv_state(nr_idle_states, names[i],
 464                                           CPUIDLE_FLAG_TIMER_STOP, stop_loop,
 465                                           target_residency, exit_latency,
 466                                           psscr_val[i], psscr_mask[i]);
 467                 }
 468 #endif
 469                 else
 470                         continue;
 471                 nr_idle_states++;
 472         }
 473 out:
 474         return nr_idle_states;
 475 }
 476
 477 /*
 478  * powernv_idle_probe()
 479  * Choose state table for shared versus dedicated partition
 480  */
 481 static int powernv_idle_probe(void)
 482 {
 483         if (cpuidle_disable != IDLE_NO_OVERRIDE)
 484                 return -ENODEV;
 485
 486         if (firmware_has_feature(FW_FEATURE_OPAL)) {
 487                 cpuidle_state_table = powernv_states;
 488                 /* Device tree can indicate more idle states */
 489                 max_idle_state = powernv_add_idle_states();
 490                 default_snooze_timeout = TICK_USEC * tb_ticks_per_usec;
 491                 if (max_idle_state > 1)
 492                         snooze_timeout_en = true;
 493         } else
 494                 return -ENODEV;
 495
 496         return 0;
 497 }
 498
 499 static int __init powernv_processor_idle_init(void)
 500 {
 501         int retval;
 502
 503         retval = powernv_idle_probe();
 504         if (retval)
 505                 return retval;
 506
 507         powernv_cpuidle_driver_init();
 508         retval = cpuidle_register(&powernv_idle_driver, NULL);
 509         if (retval) {
 510                 printk(KERN_DEBUG "Registration of powernv driver failed.\n");
 511                 return retval;
 512         }
 513
 514         retval = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
 515                                            "cpuidle/powernv:online",
 516                                            powernv_cpuidle_cpu_online, NULL);
 517         WARN_ON(retval < 0);
 518         retval = cpuhp_setup_state_nocalls(CPUHP_CPUIDLE_DEAD,
 519                                            "cpuidle/powernv:dead", NULL,
 520                                            powernv_cpuidle_cpu_dead);
 521         WARN_ON(retval < 0);
 522         printk(KERN_DEBUG "powernv_idle_driver registered\n");
 523         return 0;
 524 }
 525
 526 device_initcall(powernv_processor_idle_init);