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