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