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 struct cpuidle_driver powernv_idle_driver = {
  24         .name             = "powernv_idle",
  25         .owner            = THIS_MODULE,
  26 };
  27
  28 static int max_idle_state;
  29 static struct cpuidle_state *cpuidle_state_table;
  30 static u64 snooze_timeout;
  31 static bool snooze_timeout_en;
  32
  33 static int snooze_loop(struct cpuidle_device *dev,
  34                         struct cpuidle_driver *drv,
  35                         int index)
  36 {
  37         u64 snooze_exit_time;
  38
  39         local_irq_enable();
  40         set_thread_flag(TIF_POLLING_NRFLAG);
  41
  42         snooze_exit_time = get_tb() + snooze_timeout;
  43         ppc64_runlatch_off();
  44         while (!need_resched()) {
  45                 HMT_low();
  46                 HMT_very_low();
  47                 if (snooze_timeout_en && get_tb() > snooze_exit_time)
  48                         break;
  49         }
  50
  51         HMT_medium();
  52         ppc64_runlatch_on();
  53         clear_thread_flag(TIF_POLLING_NRFLAG);
  54         smp_mb();
  55         return index;
  56 }
  57
  58 static int nap_loop(struct cpuidle_device *dev,
  59                         struct cpuidle_driver *drv,
  60                         int index)
  61 {
  62         ppc64_runlatch_off();
  63         power7_idle();
  64         ppc64_runlatch_on();
  65         return index;
  66 }
  67
  68 /* Register for fastsleep only in oneshot mode of broadcast */
  69 #ifdef CONFIG_TICK_ONESHOT
  70 static int fastsleep_loop(struct cpuidle_device *dev,
  71                                 struct cpuidle_driver *drv,
  72                                 int index)
  73 {
  74         unsigned long old_lpcr = mfspr(SPRN_LPCR);
  75         unsigned long new_lpcr;
  76
  77         if (unlikely(system_state < SYSTEM_RUNNING))
  78                 return index;
  79
  80         new_lpcr = old_lpcr;
  81         /* Do not exit powersave upon decrementer as we've setup the timer
  82          * offload.
  83          */
  84         new_lpcr &= ~LPCR_PECE1;
  85
  86         mtspr(SPRN_LPCR, new_lpcr);
  87         power7_sleep();
  88
  89         mtspr(SPRN_LPCR, old_lpcr);
  90
  91         return index;
  92 }
  93 #endif
  94 /*
  95  * States for dedicated partition case.
  96  */
  97 static struct cpuidle_state powernv_states[CPUIDLE_STATE_MAX] = {
  98         { /* Snooze */
  99                 .name = "snooze",
 100                 .desc = "snooze",
 101                 .exit_latency = 0,
 102                 .target_residency = 0,
 103                 .enter = snooze_loop },
 104 };
 105
 106 static int powernv_cpuidle_add_cpu_notifier(struct notifier_block *n,
 107                         unsigned long action, void *hcpu)
 108 {
 109         int hotcpu = (unsigned long)hcpu;
 110         struct cpuidle_device *dev =
 111                                 per_cpu(cpuidle_devices, hotcpu);
 112
 113         if (dev && cpuidle_get_driver()) {
 114                 switch (action) {
 115                 case CPU_ONLINE:
 116                 case CPU_ONLINE_FROZEN:
 117                         cpuidle_pause_and_lock();
 118                         cpuidle_enable_device(dev);
 119                         cpuidle_resume_and_unlock();
 120                         break;
 121
 122                 case CPU_DEAD:
 123                 case CPU_DEAD_FROZEN:
 124                         cpuidle_pause_and_lock();
 125                         cpuidle_disable_device(dev);
 126                         cpuidle_resume_and_unlock();
 127                         break;
 128
 129                 default:
 130                         return NOTIFY_DONE;
 131                 }
 132         }
 133         return NOTIFY_OK;
 134 }
 135
 136 static struct notifier_block setup_hotplug_notifier = {
 137         .notifier_call = powernv_cpuidle_add_cpu_notifier,
 138 };
 139
 140 /*
 141  * powernv_cpuidle_driver_init()
 142  */
 143 static int powernv_cpuidle_driver_init(void)
 144 {
 145         int idle_state;
 146         struct cpuidle_driver *drv = &powernv_idle_driver;
 147
 148         drv->state_count = 0;
 149
 150         for (idle_state = 0; idle_state < max_idle_state; ++idle_state) {
 151                 /* Is the state not enabled? */
 152                 if (cpuidle_state_table[idle_state].enter == NULL)
 153                         continue;
 154
 155                 drv->states[drv->state_count] = /* structure copy */
 156                         cpuidle_state_table[idle_state];
 157
 158                 drv->state_count += 1;
 159         }
 160
 161         return 0;
 162 }
 163
 164 static int powernv_add_idle_states(void)
 165 {
 166         struct device_node *power_mgt;
 167         int nr_idle_states = 1; /* Snooze */
 168         int dt_idle_states;
 169         u32 latency_ns[CPUIDLE_STATE_MAX];
 170         u32 residency_ns[CPUIDLE_STATE_MAX];
 171         u32 flags[CPUIDLE_STATE_MAX];
 172         int i, rc;
 173
 174         /* Currently we have snooze statically defined */
 175
 176         power_mgt = of_find_node_by_path("/ibm,opal/power-mgt");
 177         if (!power_mgt) {
 178                 pr_warn("opal: PowerMgmt Node not found\n");
 179                 goto out;
 180         }
 181
 182         /* Read values of any property to determine the num of idle states */
 183         dt_idle_states = of_property_count_u32_elems(power_mgt, "ibm,cpu-idle-state-flags");
 184         if (dt_idle_states < 0) {
 185                 pr_warn("cpuidle-powernv: no idle states found in the DT\n");
 186                 goto out;
 187         }
 188
 189         /*
 190          * Since snooze is used as first idle state, max idle states allowed is
 191          * CPUIDLE_STATE_MAX -1
 192          */
 193         if (dt_idle_states > CPUIDLE_STATE_MAX - 1) {
 194                 pr_warn("cpuidle-powernv: discovered idle states more than allowed");
 195                 dt_idle_states = CPUIDLE_STATE_MAX - 1;
 196         }
 197
 198         if (of_property_read_u32_array(power_mgt,
 199                         "ibm,cpu-idle-state-flags", flags, dt_idle_states)) {
 200                 pr_warn("cpuidle-powernv : missing ibm,cpu-idle-state-flags in DT\n");
 201                 goto out;
 202         }
 203
 204         if (of_property_read_u32_array(power_mgt,
 205                 "ibm,cpu-idle-state-latencies-ns", latency_ns,
 206                 dt_idle_states)) {
 207                 pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-latencies-ns in DT\n");
 208                 goto out;
 209         }
 210
 211         rc = of_property_read_u32_array(power_mgt,
 212                 "ibm,cpu-idle-state-residency-ns", residency_ns, dt_idle_states);
 213
 214         for (i = 0; i < dt_idle_states; i++) {
 215
 216                 /*
 217                  * Cpuidle accepts exit_latency and target_residency in us.
 218                  * Use default target_residency values if f/w does not expose it.
 219                  */
 220                 if (flags[i] & OPAL_PM_NAP_ENABLED) {
 221                         /* Add NAP state */
 222                         strcpy(powernv_states[nr_idle_states].name, "Nap");
 223                         strcpy(powernv_states[nr_idle_states].desc, "Nap");
 224                         powernv_states[nr_idle_states].flags = 0;
 225                         powernv_states[nr_idle_states].target_residency = 100;
 226                         powernv_states[nr_idle_states].enter = nap_loop;
 227                 }
 228
 229                 /*
 230                  * All cpuidle states with CPUIDLE_FLAG_TIMER_STOP set must come
 231                  * within this config dependency check.
 232                  */
 233 #ifdef CONFIG_TICK_ONESHOT
 234                 if (flags[i] & OPAL_PM_SLEEP_ENABLED ||
 235                         flags[i] & OPAL_PM_SLEEP_ENABLED_ER1) {
 236                         /* Add FASTSLEEP state */
 237                         strcpy(powernv_states[nr_idle_states].name, "FastSleep");
 238                         strcpy(powernv_states[nr_idle_states].desc, "FastSleep");
 239                         powernv_states[nr_idle_states].flags = CPUIDLE_FLAG_TIMER_STOP;
 240                         powernv_states[nr_idle_states].target_residency = 300000;
 241                         powernv_states[nr_idle_states].enter = fastsleep_loop;
 242                 }
 243 #endif
 244                 powernv_states[nr_idle_states].exit_latency =
 245                                 ((unsigned int)latency_ns[i]) / 1000;
 246
 247                 if (!rc) {
 248                         powernv_states[nr_idle_states].target_residency =
 249                                 ((unsigned int)residency_ns[i]) / 1000;
 250                 }
 251
 252                 nr_idle_states++;
 253         }
 254 out:
 255         return nr_idle_states;
 256 }
 257
 258 /*
 259  * powernv_idle_probe()
 260  * Choose state table for shared versus dedicated partition
 261  */
 262 static int powernv_idle_probe(void)
 263 {
 264         if (cpuidle_disable != IDLE_NO_OVERRIDE)
 265                 return -ENODEV;
 266
 267         if (firmware_has_feature(FW_FEATURE_OPAL)) {
 268                 cpuidle_state_table = powernv_states;
 269                 /* Device tree can indicate more idle states */
 270                 max_idle_state = powernv_add_idle_states();
 271                 if (max_idle_state > 1) {
 272                         snooze_timeout_en = true;
 273                         snooze_timeout = powernv_states[1].target_residency *
 274                                          tb_ticks_per_usec;
 275                 }
 276         } else
 277                 return -ENODEV;
 278
 279         return 0;
 280 }
 281
 282 static int __init powernv_processor_idle_init(void)
 283 {
 284         int retval;
 285
 286         retval = powernv_idle_probe();
 287         if (retval)
 288                 return retval;
 289
 290         powernv_cpuidle_driver_init();
 291         retval = cpuidle_register(&powernv_idle_driver, NULL);
 292         if (retval) {
 293                 printk(KERN_DEBUG "Registration of powernv driver failed.\n");
 294                 return retval;
 295         }
 296
 297         register_cpu_notifier(&setup_hotplug_notifier);
 298         printk(KERN_DEBUG "powernv_idle_driver registered\n");
 299         return 0;
 300 }
 301
 302 device_initcall(powernv_processor_idle_init);