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
  23 #define POWERNV_THRESHOLD_LATENCY_NS 200000
  24
  25 struct cpuidle_driver powernv_idle_driver = {
  26         .name             = "powernv_idle",
  27         .owner            = THIS_MODULE,
  28 };
  29
  30 static int max_idle_state;
  31 static struct cpuidle_state *cpuidle_state_table;
  32
  33 static u64 stop_psscr_table[CPUIDLE_STATE_MAX];
  34
  35 static u64 snooze_timeout;
  36 static bool snooze_timeout_en;
  37
  38 static int snooze_loop(struct cpuidle_device *dev,
  39                         struct cpuidle_driver *drv,
  40                         int index)
  41 {
  42         u64 snooze_exit_time;
  43
  44         local_irq_enable();
  45         set_thread_flag(TIF_POLLING_NRFLAG);
  46
  47         snooze_exit_time = get_tb() + snooze_timeout;
  48         ppc64_runlatch_off();
  49         while (!need_resched()) {
  50                 HMT_low();
  51                 HMT_very_low();
  52                 if (snooze_timeout_en && get_tb() > snooze_exit_time)
  53                         break;
  54         }
  55
  56         HMT_medium();
  57         ppc64_runlatch_on();
  58         clear_thread_flag(TIF_POLLING_NRFLAG);
  59         smp_mb();
  60         return index;
  61 }
  62
  63 static int nap_loop(struct cpuidle_device *dev,
  64                         struct cpuidle_driver *drv,
  65                         int index)
  66 {
  67         ppc64_runlatch_off();
  68         power7_idle();
  69         ppc64_runlatch_on();
  70         return index;
  71 }
  72
  73 /* Register for fastsleep only in oneshot mode of broadcast */
  74 #ifdef CONFIG_TICK_ONESHOT
  75 static int fastsleep_loop(struct cpuidle_device *dev,
  76                                 struct cpuidle_driver *drv,
  77                                 int index)
  78 {
  79         unsigned long old_lpcr = mfspr(SPRN_LPCR);
  80         unsigned long new_lpcr;
  81
  82         if (unlikely(system_state < SYSTEM_RUNNING))
  83                 return index;
  84
  85         new_lpcr = old_lpcr;
  86         /* Do not exit powersave upon decrementer as we've setup the timer
  87          * offload.
  88          */
  89         new_lpcr &= ~LPCR_PECE1;
  90
  91         mtspr(SPRN_LPCR, new_lpcr);
  92         power7_sleep();
  93
  94         mtspr(SPRN_LPCR, old_lpcr);
  95
  96         return index;
  97 }
  98 #endif
  99
 100 static int stop_loop(struct cpuidle_device *dev,
 101                      struct cpuidle_driver *drv,
 102                      int index)
 103 {
 104         ppc64_runlatch_off();
 105         power9_idle_stop(stop_psscr_table[index]);
 106         ppc64_runlatch_on();
 107         return index;
 108 }
 109
 110 /*
 111  * States for dedicated partition case.
 112  */
 113 static struct cpuidle_state powernv_states[CPUIDLE_STATE_MAX] = {
 114         { /* Snooze */
 115                 .name = "snooze",
 116                 .desc = "snooze",
 117                 .exit_latency = 0,
 118                 .target_residency = 0,
 119                 .enter = snooze_loop },
 120 };
 121
 122 static int powernv_cpuidle_add_cpu_notifier(struct notifier_block *n,
 123                         unsigned long action, void *hcpu)
 124 {
 125         int hotcpu = (unsigned long)hcpu;
 126         struct cpuidle_device *dev =
 127                                 per_cpu(cpuidle_devices, hotcpu);
 128
 129         if (dev && cpuidle_get_driver()) {
 130                 switch (action) {
 131                 case CPU_ONLINE:
 132                 case CPU_ONLINE_FROZEN:
 133                         cpuidle_pause_and_lock();
 134                         cpuidle_enable_device(dev);
 135                         cpuidle_resume_and_unlock();
 136                         break;
 137
 138                 case CPU_DEAD:
 139                 case CPU_DEAD_FROZEN:
 140                         cpuidle_pause_and_lock();
 141                         cpuidle_disable_device(dev);
 142                         cpuidle_resume_and_unlock();
 143                         break;
 144
 145                 default:
 146                         return NOTIFY_DONE;
 147                 }
 148         }
 149         return NOTIFY_OK;
 150 }
 151
 152 static struct notifier_block setup_hotplug_notifier = {
 153         .notifier_call = powernv_cpuidle_add_cpu_notifier,
 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         return 0;
 178 }
 179
 180 static int powernv_add_idle_states(void)
 181 {
 182         struct device_node *power_mgt;
 183         int nr_idle_states = 1; /* Snooze */
 184         int dt_idle_states;
 185         u32 latency_ns[CPUIDLE_STATE_MAX];
 186         u32 residency_ns[CPUIDLE_STATE_MAX];
 187         u32 flags[CPUIDLE_STATE_MAX];
 188         u64 psscr_val[CPUIDLE_STATE_MAX];
 189         const char *names[CPUIDLE_STATE_MAX];
 190         int i, rc;
 191
 192         /* Currently we have snooze statically defined */
 193
 194         power_mgt = of_find_node_by_path("/ibm,opal/power-mgt");
 195         if (!power_mgt) {
 196                 pr_warn("opal: PowerMgmt Node not found\n");
 197                 goto out;
 198         }
 199
 200         /* Read values of any property to determine the num of idle states */
 201         dt_idle_states = of_property_count_u32_elems(power_mgt, "ibm,cpu-idle-state-flags");
 202         if (dt_idle_states < 0) {
 203                 pr_warn("cpuidle-powernv: no idle states found in the DT\n");
 204                 goto out;
 205         }
 206
 207         /*
 208          * Since snooze is used as first idle state, max idle states allowed is
 209          * CPUIDLE_STATE_MAX -1
 210          */
 211         if (dt_idle_states > CPUIDLE_STATE_MAX - 1) {
 212                 pr_warn("cpuidle-powernv: discovered idle states more than allowed");
 213                 dt_idle_states = CPUIDLE_STATE_MAX - 1;
 214         }
 215
 216         if (of_property_read_u32_array(power_mgt,
 217                         "ibm,cpu-idle-state-flags", flags, dt_idle_states)) {
 218                 pr_warn("cpuidle-powernv : missing ibm,cpu-idle-state-flags in DT\n");
 219                 goto out;
 220         }
 221
 222         if (of_property_read_u32_array(power_mgt,
 223                 "ibm,cpu-idle-state-latencies-ns", latency_ns,
 224                 dt_idle_states)) {
 225                 pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-latencies-ns in DT\n");
 226                 goto out;
 227         }
 228         if (of_property_read_string_array(power_mgt,
 229                 "ibm,cpu-idle-state-names", names, dt_idle_states) < 0) {
 230                 pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-names in DT\n");
 231                 goto out;
 232         }
 233
 234         /*
 235          * If the idle states use stop instruction, probe for psscr values
 236          * which are necessary to specify required stop level.
 237          */
 238         if (flags[0] & (OPAL_PM_STOP_INST_FAST | OPAL_PM_STOP_INST_DEEP))
 239                 if (of_property_read_u64_array(power_mgt,
 240                     "ibm,cpu-idle-state-psscr", psscr_val, dt_idle_states)) {
 241                         pr_warn("cpuidle-powernv: missing ibm,cpu-idle-states-psscr in DT\n");
 242                         goto out;
 243                 }
 244
 245         rc = of_property_read_u32_array(power_mgt,
 246                 "ibm,cpu-idle-state-residency-ns", residency_ns, dt_idle_states);
 247
 248         for (i = 0; i < dt_idle_states; i++) {
 249                 /*
 250                  * If an idle state has exit latency beyond
 251                  * POWERNV_THRESHOLD_LATENCY_NS then don't use it
 252                  * in cpu-idle.
 253                  */
 254                 if (latency_ns[i] > POWERNV_THRESHOLD_LATENCY_NS)
 255                         continue;
 256
 257                 /*
 258                  * Cpuidle accepts exit_latency and target_residency in us.
 259                  * Use default target_residency values if f/w does not expose it.
 260                  */
 261                 if (flags[i] & OPAL_PM_NAP_ENABLED) {
 262                         /* Add NAP state */
 263                         strcpy(powernv_states[nr_idle_states].name, "Nap");
 264                         strcpy(powernv_states[nr_idle_states].desc, "Nap");
 265                         powernv_states[nr_idle_states].flags = 0;
 266                         powernv_states[nr_idle_states].target_residency = 100;
 267                         powernv_states[nr_idle_states].enter = nap_loop;
 268                 } else if ((flags[i] & OPAL_PM_STOP_INST_FAST) &&
 269                                 !(flags[i] & OPAL_PM_TIMEBASE_STOP)) {
 270                         strncpy(powernv_states[nr_idle_states].name,
 271                                 names[i], CPUIDLE_NAME_LEN);
 272                         strncpy(powernv_states[nr_idle_states].desc,
 273                                 names[i], CPUIDLE_NAME_LEN);
 274                         powernv_states[nr_idle_states].flags = 0;
 275
 276                         powernv_states[nr_idle_states].enter = stop_loop;
 277                         stop_psscr_table[nr_idle_states] = psscr_val[i];
 278                 }
 279
 280                 /*
 281                  * All cpuidle states with CPUIDLE_FLAG_TIMER_STOP set must come
 282                  * within this config dependency check.
 283                  */
 284 #ifdef CONFIG_TICK_ONESHOT
 285                 if (flags[i] & OPAL_PM_SLEEP_ENABLED ||
 286                         flags[i] & OPAL_PM_SLEEP_ENABLED_ER1) {
 287                         /* Add FASTSLEEP state */
 288                         strcpy(powernv_states[nr_idle_states].name, "FastSleep");
 289                         strcpy(powernv_states[nr_idle_states].desc, "FastSleep");
 290                         powernv_states[nr_idle_states].flags = CPUIDLE_FLAG_TIMER_STOP;
 291                         powernv_states[nr_idle_states].target_residency = 300000;
 292                         powernv_states[nr_idle_states].enter = fastsleep_loop;
 293                 } else if ((flags[i] & OPAL_PM_STOP_INST_DEEP) &&
 294                                 (flags[i] & OPAL_PM_TIMEBASE_STOP)) {
 295                         strncpy(powernv_states[nr_idle_states].name,
 296                                 names[i], CPUIDLE_NAME_LEN);
 297                         strncpy(powernv_states[nr_idle_states].desc,
 298                                 names[i], CPUIDLE_NAME_LEN);
 299
 300                         powernv_states[nr_idle_states].flags = CPUIDLE_FLAG_TIMER_STOP;
 301                         powernv_states[nr_idle_states].enter = stop_loop;
 302                         stop_psscr_table[nr_idle_states] = psscr_val[i];
 303                 }
 304 #endif
 305                 powernv_states[nr_idle_states].exit_latency =
 306                                 ((unsigned int)latency_ns[i]) / 1000;
 307
 308                 if (!rc) {
 309                         powernv_states[nr_idle_states].target_residency =
 310                                 ((unsigned int)residency_ns[i]) / 1000;
 311                 }
 312
 313                 nr_idle_states++;
 314         }
 315 out:
 316         return nr_idle_states;
 317 }
 318
 319 /*
 320  * powernv_idle_probe()
 321  * Choose state table for shared versus dedicated partition
 322  */
 323 static int powernv_idle_probe(void)
 324 {
 325         if (cpuidle_disable != IDLE_NO_OVERRIDE)
 326                 return -ENODEV;
 327
 328         if (firmware_has_feature(FW_FEATURE_OPAL)) {
 329                 cpuidle_state_table = powernv_states;
 330                 /* Device tree can indicate more idle states */
 331                 max_idle_state = powernv_add_idle_states();
 332                 if (max_idle_state > 1) {
 333                         snooze_timeout_en = true;
 334                         snooze_timeout = powernv_states[1].target_residency *
 335                                          tb_ticks_per_usec;
 336                 }
 337         } else
 338                 return -ENODEV;
 339
 340         return 0;
 341 }
 342
 343 static int __init powernv_processor_idle_init(void)
 344 {
 345         int retval;
 346
 347         retval = powernv_idle_probe();
 348         if (retval)
 349                 return retval;
 350
 351         powernv_cpuidle_driver_init();
 352         retval = cpuidle_register(&powernv_idle_driver, NULL);
 353         if (retval) {
 354                 printk(KERN_DEBUG "Registration of powernv driver failed.\n");
 355                 return retval;
 356         }
 357
 358         register_cpu_notifier(&setup_hotplug_notifier);
 359         printk(KERN_DEBUG "powernv_idle_driver registered\n");
 360         return 0;
 361 }
 362
 363 device_initcall(powernv_processor_idle_init);