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