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