drivers/cpuidle/cpuidle-powernv.c

   1 /*
   2  *  cpuidle-powernv - idle state cpuidle driver.
   3  *  Adapted from drivers/cpuidle/cpuidle-pseries
   4  *
   5  */
   6
   7 #include <linux/kernel.h>
   8 #include <linux/module.h>
   9 #include <linux/init.h>
  10 #include <linux/moduleparam.h>
  11 #include <linux/cpuidle.h>
  12 #include <linux/cpu.h>
  13 #include <linux/notifier.h>
  14 #include <linux/clockchips.h>
  15 #include <linux/of.h>
  16 #include <linux/slab.h>
  17
  18 #include <asm/machdep.h>
  19 #include <asm/firmware.h>
  20 #include <asm/opal.h>
  21 #include <asm/runlatch.h>
  22 #include <asm/cpuidle.h>
  23
  24 /*
  25  * Expose only those Hardware idle states via the cpuidle framework
  26  * that have latency value below POWERNV_THRESHOLD_LATENCY_NS.
  27  */
  28 #define POWERNV_THRESHOLD_LATENCY_NS 200000
  29
  30 static struct cpuidle_driver powernv_idle_driver = {
  31         .name             = "powernv_idle",
  32         .owner            = THIS_MODULE,
  33 };
  34
  35 static int max_idle_state;
  36 static struct cpuidle_state *cpuidle_state_table;
  37
  38 struct stop_psscr_table {
  39         u64 val;
  40         u64 mask;
  41 };
  42
  43 static struct stop_psscr_table stop_psscr_table[CPUIDLE_STATE_MAX];
  44
  45 static u64 snooze_timeout;
  46 static bool snooze_timeout_en;
  47
  48 static int snooze_loop(struct cpuidle_device *dev,
  49                         struct cpuidle_driver *drv,
  50                         int index)
  51 {
  52         u64 snooze_exit_time;
  53
  54         local_irq_enable();
  55         set_thread_flag(TIF_POLLING_NRFLAG);
  56
  57         snooze_exit_time = get_tb() + snooze_timeout;
  58         ppc64_runlatch_off();
  59         HMT_very_low();
  60         while (!need_resched()) {
  61                 if (likely(snooze_timeout_en) && get_tb() > snooze_exit_time)
  62                         break;
  63         }
  64
  65         HMT_medium();
  66         ppc64_runlatch_on();
  67         clear_thread_flag(TIF_POLLING_NRFLAG);
  68         smp_mb();
  69         return index;
  70 }
  71
  72 static int nap_loop(struct cpuidle_device *dev,
  73                         struct cpuidle_driver *drv,
  74                         int index)
  75 {
  76         ppc64_runlatch_off();
  77         power7_idle();
  78         ppc64_runlatch_on();
  79         return index;
  80 }
  81
  82 /* Register for fastsleep only in oneshot mode of broadcast */
  83 #ifdef CONFIG_TICK_ONESHOT
  84 static int fastsleep_loop(struct cpuidle_device *dev,
  85                                 struct cpuidle_driver *drv,
  86                                 int index)
  87 {
  88         unsigned long old_lpcr = mfspr(SPRN_LPCR);
  89         unsigned long new_lpcr;
  90
  91         if (unlikely(system_state < SYSTEM_RUNNING))
  92                 return index;
  93
  94         new_lpcr = old_lpcr;
  95         /* Do not exit powersave upon decrementer as we've setup the timer
  96          * offload.
  97          */
  98         new_lpcr &= ~LPCR_PECE1;
  99
 100         mtspr(SPRN_LPCR, new_lpcr);
 101         power7_sleep();
 102
 103         mtspr(SPRN_LPCR, old_lpcr);
 104
 105         return index;
 106 }
 107 #endif
 108
 109 static int stop_loop(struct cpuidle_device *dev,
 110                      struct cpuidle_driver *drv,
 111                      int index)
 112 {
 113         ppc64_runlatch_off();
 114         power9_idle_stop(stop_psscr_table[index].val,
 115                          stop_psscr_table[index].mask);
 116         ppc64_runlatch_on();
 117         return index;
 118 }
 119
 120 /*
 121  * States for dedicated partition case.
 122  */
 123 static struct cpuidle_state powernv_states[CPUIDLE_STATE_MAX] = {
 124         { /* Snooze */
 125                 .name = "snooze",
 126                 .desc = "snooze",
 127                 .exit_latency = 0,
 128                 .target_residency = 0,
 129                 .enter = snooze_loop },
 130 };
 131
 132 static int powernv_cpuidle_cpu_online(unsigned int cpu)
 133 {
 134         struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu);
 135
 136         if (dev && cpuidle_get_driver()) {
 137                 cpuidle_pause_and_lock();
 138                 cpuidle_enable_device(dev);
 139                 cpuidle_resume_and_unlock();
 140         }
 141         return 0;
 142 }
 143
 144 static int powernv_cpuidle_cpu_dead(unsigned int cpu)
 145 {
 146         struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu);
 147
 148         if (dev && cpuidle_get_driver()) {
 149                 cpuidle_pause_and_lock();
 150                 cpuidle_disable_device(dev);
 151                 cpuidle_resume_and_unlock();
 152         }
 153         return 0;
 154 }
 155
 156 /*
 157  * powernv_cpuidle_driver_init()
 158  */
 159 static int powernv_cpuidle_driver_init(void)
 160 {
 161         int idle_state;
 162         struct cpuidle_driver *drv = &powernv_idle_driver;
 163
 164         drv->state_count = 0;
 165
 166         for (idle_state = 0; idle_state < max_idle_state; ++idle_state) {
 167                 /* Is the state not enabled? */
 168                 if (cpuidle_state_table[idle_state].enter == NULL)
 169                         continue;
 170
 171                 drv->states[drv->state_count] = /* structure copy */
 172                         cpuidle_state_table[idle_state];
 173
 174                 drv->state_count += 1;
 175         }
 176
 177         /*
 178          * On the PowerNV platform cpu_present may be less than cpu_possible in
 179          * cases when firmware detects the CPU, but it is not available to the
 180          * OS.  If CONFIG_HOTPLUG_CPU=n, then such CPUs are not hotplugable at
 181          * run time and hence cpu_devices are not created for those CPUs by the
 182          * generic topology_init().
 183          *
 184          * drv->cpumask defaults to cpu_possible_mask in
 185          * __cpuidle_driver_init().  This breaks cpuidle on PowerNV where
 186          * cpu_devices are not created for CPUs in cpu_possible_mask that
 187          * cannot be hot-added later at run time.
 188          *
 189          * Trying cpuidle_register_device() on a CPU without a cpu_device is
 190          * incorrect, so pass a correct CPU mask to the generic cpuidle driver.
 191          */
 192
 193         drv->cpumask = (struct cpumask *)cpu_present_mask;
 194
 195         return 0;
 196 }
 197
 198 static inline void add_powernv_state(int index, const char *name,
 199                                      unsigned int flags,
 200                                      int (*idle_fn)(struct cpuidle_device *,
 201                                                     struct cpuidle_driver *,
 202                                                     int),
 203                                      unsigned int target_residency,
 204                                      unsigned int exit_latency,
 205                                      u64 psscr_val, u64 psscr_mask)
 206 {
 207         strlcpy(powernv_states[index].name, name, CPUIDLE_NAME_LEN);
 208         strlcpy(powernv_states[index].desc, name, CPUIDLE_NAME_LEN);
 209         powernv_states[index].flags = flags;
 210         powernv_states[index].target_residency = target_residency;
 211         powernv_states[index].exit_latency = exit_latency;
 212         powernv_states[index].enter = idle_fn;
 213         stop_psscr_table[index].val = psscr_val;
 214         stop_psscr_table[index].mask = psscr_mask;
 215 }
 216
 217 /*
 218  * Returns 0 if prop1_len == prop2_len. Else returns -1
 219  */
 220 static inline int validate_dt_prop_sizes(const char *prop1, int prop1_len,
 221                                          const char *prop2, int prop2_len)
 222 {
 223         if (prop1_len == prop2_len)
 224                 return 0;
 225
 226         pr_warn("cpuidle-powernv: array sizes don't match for %s and %s\n",
 227                 prop1, prop2);
 228         return -1;
 229 }
 230
 231 static int powernv_add_idle_states(void)
 232 {
 233         struct device_node *power_mgt;
 234         int nr_idle_states = 1; /* Snooze */
 235         int dt_idle_states, count;
 236         u32 latency_ns[CPUIDLE_STATE_MAX];
 237         u32 residency_ns[CPUIDLE_STATE_MAX];
 238         u32 flags[CPUIDLE_STATE_MAX];
 239         u64 psscr_val[CPUIDLE_STATE_MAX];
 240         u64 psscr_mask[CPUIDLE_STATE_MAX];
 241         const char *names[CPUIDLE_STATE_MAX];
 242         u32 has_stop_states = 0;
 243         int i, rc;
 244
 245         /* Currently we have snooze statically defined */
 246
 247         power_mgt = of_find_node_by_path("/ibm,opal/power-mgt");
 248         if (!power_mgt) {
 249                 pr_warn("opal: PowerMgmt Node not found\n");
 250                 goto out;
 251         }
 252
 253         /* Read values of any property to determine the num of idle states */
 254         dt_idle_states = of_property_count_u32_elems(power_mgt, "ibm,cpu-idle-state-flags");
 255         if (dt_idle_states < 0) {
 256                 pr_warn("cpuidle-powernv: no idle states found in the DT\n");
 257                 goto out;
 258         }
 259
 260         count = of_property_count_u32_elems(power_mgt,
 261                                             "ibm,cpu-idle-state-latencies-ns");
 262
 263         if (validate_dt_prop_sizes("ibm,cpu-idle-state-flags", dt_idle_states,
 264                                    "ibm,cpu-idle-state-latencies-ns",
 265                                    count) != 0)
 266                 goto out;
 267
 268         count = of_property_count_strings(power_mgt,
 269                                           "ibm,cpu-idle-state-names");
 270         if (validate_dt_prop_sizes("ibm,cpu-idle-state-flags", dt_idle_states,
 271                                    "ibm,cpu-idle-state-names",
 272                                    count) != 0)
 273                 goto out;
 274
 275         /*
 276          * Since snooze is used as first idle state, max idle states allowed is
 277          * CPUIDLE_STATE_MAX -1
 278          */
 279         if (dt_idle_states > CPUIDLE_STATE_MAX - 1) {
 280                 pr_warn("cpuidle-powernv: discovered idle states more than allowed");
 281                 dt_idle_states = CPUIDLE_STATE_MAX - 1;
 282         }
 283
 284         if (of_property_read_u32_array(power_mgt,
 285                         "ibm,cpu-idle-state-flags", flags, dt_idle_states)) {
 286                 pr_warn("cpuidle-powernv : missing ibm,cpu-idle-state-flags in DT\n");
 287                 goto out;
 288         }
 289
 290         if (of_property_read_u32_array(power_mgt,
 291                 "ibm,cpu-idle-state-latencies-ns", latency_ns,
 292                 dt_idle_states)) {
 293                 pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-latencies-ns in DT\n");
 294                 goto out;
 295         }
 296         if (of_property_read_string_array(power_mgt,
 297                 "ibm,cpu-idle-state-names", names, dt_idle_states) < 0) {
 298                 pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-names in DT\n");
 299                 goto out;
 300         }
 301
 302         /*
 303          * If the idle states use stop instruction, probe for psscr values
 304          * and psscr mask which are necessary to specify required stop level.
 305          */
 306         has_stop_states = (flags[0] &
 307                            (OPAL_PM_STOP_INST_FAST | OPAL_PM_STOP_INST_DEEP));
 308         if (has_stop_states) {
 309                 count = of_property_count_u64_elems(power_mgt,
 310                                                     "ibm,cpu-idle-state-psscr");
 311                 if (validate_dt_prop_sizes("ibm,cpu-idle-state-flags",
 312                                            dt_idle_states,
 313                                            "ibm,cpu-idle-state-psscr",
 314                                            count) != 0)
 315                         goto out;
 316
 317                 count = of_property_count_u64_elems(power_mgt,
 318                                                     "ibm,cpu-idle-state-psscr-mask");
 319                 if (validate_dt_prop_sizes("ibm,cpu-idle-state-flags",
 320                                            dt_idle_states,
 321                                            "ibm,cpu-idle-state-psscr-mask",
 322                                            count) != 0)
 323                         goto out;
 324
 325                 if (of_property_read_u64_array(power_mgt,
 326                     "ibm,cpu-idle-state-psscr", psscr_val, dt_idle_states)) {
 327                         pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-psscr in DT\n");
 328                         goto out;
 329                 }
 330
 331                 if (of_property_read_u64_array(power_mgt,
 332                                                "ibm,cpu-idle-state-psscr-mask",
 333                                                 psscr_mask, dt_idle_states)) {
 334                         pr_warn("cpuidle-powernv:Missing ibm,cpu-idle-state-psscr-mask in DT\n");
 335                         goto out;
 336                 }
 337         }
 338
 339         count = of_property_count_u32_elems(power_mgt,
 340                                             "ibm,cpu-idle-state-residency-ns");
 341
 342         if (count < 0) {
 343                 rc = count;
 344         } else if (validate_dt_prop_sizes("ibm,cpu-idle-state-flags",
 345                                           dt_idle_states,
 346                                           "ibm,cpu-idle-state-residency-ns",
 347                                           count) != 0) {
 348                 goto out;
 349         } else {
 350                 rc = of_property_read_u32_array(power_mgt,
 351                                                 "ibm,cpu-idle-state-residency-ns",
 352                                                 residency_ns, dt_idle_states);
 353         }
 354
 355         for (i = 0; i < dt_idle_states; i++) {
 356                 unsigned int exit_latency, target_residency;
 357                 /*
 358                  * If an idle state has exit latency beyond
 359                  * POWERNV_THRESHOLD_LATENCY_NS then don't use it
 360                  * in cpu-idle.
 361                  */
 362                 if (latency_ns[i] > POWERNV_THRESHOLD_LATENCY_NS)
 363                         continue;
 364                 /*
 365                  * Firmware passes residency and latency values in ns.
 366                  * cpuidle expects it in us.
 367                  */
 368                 exit_latency = latency_ns[i] / 1000;
 369                 if (!rc)
 370                         target_residency = residency_ns[i] / 1000;
 371                 else
 372                         target_residency = 0;
 373
 374                 if (has_stop_states) {
 375                         int err = validate_psscr_val_mask(&psscr_val[i],
 376                                                           &psscr_mask[i],
 377                                                           flags[i]);
 378                         if (err) {
 379                                 report_invalid_psscr_val(psscr_val[i], err);
 380                                 continue;
 381                         }
 382                 }
 383
 384                 /*
 385                  * For nap and fastsleep, use default target_residency
 386                  * values if f/w does not expose it.
 387                  */
 388                 if (flags[i] & OPAL_PM_NAP_ENABLED) {
 389                         if (!rc)
 390                                 target_residency = 100;
 391                         /* Add NAP state */
 392                         add_powernv_state(nr_idle_states, "Nap",
 393                                           CPUIDLE_FLAG_NONE, nap_loop,
 394                                           target_residency, exit_latency, 0, 0);
 395                 } else if ((flags[i] & OPAL_PM_STOP_INST_FAST) &&
 396                                 !(flags[i] & OPAL_PM_TIMEBASE_STOP)) {
 397                         add_powernv_state(nr_idle_states, names[i],
 398                                           CPUIDLE_FLAG_NONE, stop_loop,
 399                                           target_residency, exit_latency,
 400                                           psscr_val[i], psscr_mask[i]);
 401                 }
 402
 403                 /*
 404                  * All cpuidle states with CPUIDLE_FLAG_TIMER_STOP set must come
 405                  * within this config dependency check.
 406                  */
 407 #ifdef CONFIG_TICK_ONESHOT
 408                 if (flags[i] & OPAL_PM_SLEEP_ENABLED ||
 409                         flags[i] & OPAL_PM_SLEEP_ENABLED_ER1) {
 410                         if (!rc)
 411                                 target_residency = 300000;
 412                         /* Add FASTSLEEP state */
 413                         add_powernv_state(nr_idle_states, "FastSleep",
 414                                           CPUIDLE_FLAG_TIMER_STOP,
 415                                           fastsleep_loop,
 416                                           target_residency, exit_latency, 0, 0);
 417                 } else if ((flags[i] & OPAL_PM_STOP_INST_DEEP) &&
 418                                 (flags[i] & OPAL_PM_TIMEBASE_STOP)) {
 419                         add_powernv_state(nr_idle_states, names[i],
 420                                           CPUIDLE_FLAG_TIMER_STOP, stop_loop,
 421                                           target_residency, exit_latency,
 422                                           psscr_val[i], psscr_mask[i]);
 423                 }
 424 #endif
 425                 nr_idle_states++;
 426         }
 427 out:
 428         return nr_idle_states;
 429 }
 430
 431 /*
 432  * powernv_idle_probe()
 433  * Choose state table for shared versus dedicated partition
 434  */
 435 static int powernv_idle_probe(void)
 436 {
 437         if (cpuidle_disable != IDLE_NO_OVERRIDE)
 438                 return -ENODEV;
 439
 440         if (firmware_has_feature(FW_FEATURE_OPAL)) {
 441                 cpuidle_state_table = powernv_states;
 442                 /* Device tree can indicate more idle states */
 443                 max_idle_state = powernv_add_idle_states();
 444                 if (max_idle_state > 1) {
 445                         snooze_timeout_en = true;
 446                         snooze_timeout = powernv_states[1].target_residency *
 447                                          tb_ticks_per_usec;
 448                 }
 449         } else
 450                 return -ENODEV;
 451
 452         return 0;
 453 }
 454
 455 static int __init powernv_processor_idle_init(void)
 456 {
 457         int retval;
 458
 459         retval = powernv_idle_probe();
 460         if (retval)
 461                 return retval;
 462
 463         powernv_cpuidle_driver_init();
 464         retval = cpuidle_register(&powernv_idle_driver, NULL);
 465         if (retval) {
 466                 printk(KERN_DEBUG "Registration of powernv driver failed.\n");
 467                 return retval;
 468         }
 469
 470         retval = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
 471                                            "cpuidle/powernv:online",
 472                                            powernv_cpuidle_cpu_online, NULL);
 473         WARN_ON(retval < 0);
 474         retval = cpuhp_setup_state_nocalls(CPUHP_CPUIDLE_DEAD,
 475                                            "cpuidle/powernv:dead", NULL,
 476                                            powernv_cpuidle_cpu_dead);
 477         WARN_ON(retval < 0);
 478         printk(KERN_DEBUG "powernv_idle_driver registered\n");
 479         return 0;
 480 }
 481
 482 device_initcall(powernv_processor_idle_init);