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