kernel/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 MAX_POWERNV_IDLE_STATES 8
  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 int snooze_loop(struct cpuidle_device *dev,
  34                         struct cpuidle_driver *drv,
  35                         int index)
  36 {
  37         local_irq_enable();
  38         set_thread_flag(TIF_POLLING_NRFLAG);
  39
  40         ppc64_runlatch_off();
  41         while (!need_resched()) {
  42                 HMT_low();
  43                 HMT_very_low();
  44         }
  45
  46         HMT_medium();
  47         ppc64_runlatch_on();
  48         clear_thread_flag(TIF_POLLING_NRFLAG);
  49         smp_mb();
  50         return index;
  51 }
  52
  53 static int nap_loop(struct cpuidle_device *dev,
  54                         struct cpuidle_driver *drv,
  55                         int index)
  56 {
  57         ppc64_runlatch_off();
  58         power7_idle();
  59         ppc64_runlatch_on();
  60         return index;
  61 }
  62
  63 /* Register for fastsleep only in oneshot mode of broadcast */
  64 #ifdef CONFIG_TICK_ONESHOT
  65 static int fastsleep_loop(struct cpuidle_device *dev,
  66                                 struct cpuidle_driver *drv,
  67                                 int index)
  68 {
  69         unsigned long old_lpcr = mfspr(SPRN_LPCR);
  70         unsigned long new_lpcr;
  71
  72         if (unlikely(system_state < SYSTEM_RUNNING))
  73                 return index;
  74
  75         new_lpcr = old_lpcr;
  76         /* Do not exit powersave upon decrementer as we've setup the timer
  77          * offload.
  78          */
  79         new_lpcr &= ~LPCR_PECE1;
  80
  81         mtspr(SPRN_LPCR, new_lpcr);
  82         power7_sleep();
  83
  84         mtspr(SPRN_LPCR, old_lpcr);
  85
  86         return index;
  87 }
  88 #endif
  89 /*
  90  * States for dedicated partition case.
  91  */
  92 static struct cpuidle_state powernv_states[MAX_POWERNV_IDLE_STATES] = {
  93         { /* Snooze */
  94                 .name = "snooze",
  95                 .desc = "snooze",
  96                 .exit_latency = 0,
  97                 .target_residency = 0,
  98                 .enter = &snooze_loop },
  99 };
 100
 101 static int powernv_cpuidle_add_cpu_notifier(struct notifier_block *n,
 102                         unsigned long action, void *hcpu)
 103 {
 104         int hotcpu = (unsigned long)hcpu;
 105         struct cpuidle_device *dev =
 106                                 per_cpu(cpuidle_devices, hotcpu);
 107
 108         if (dev && cpuidle_get_driver()) {
 109                 switch (action) {
 110                 case CPU_ONLINE:
 111                 case CPU_ONLINE_FROZEN:
 112                         cpuidle_pause_and_lock();
 113                         cpuidle_enable_device(dev);
 114                         cpuidle_resume_and_unlock();
 115                         break;
 116
 117                 case CPU_DEAD:
 118                 case CPU_DEAD_FROZEN:
 119                         cpuidle_pause_and_lock();
 120                         cpuidle_disable_device(dev);
 121                         cpuidle_resume_and_unlock();
 122                         break;
 123
 124                 default:
 125                         return NOTIFY_DONE;
 126                 }
 127         }
 128         return NOTIFY_OK;
 129 }
 130
 131 static struct notifier_block setup_hotplug_notifier = {
 132         .notifier_call = powernv_cpuidle_add_cpu_notifier,
 133 };
 134
 135 /*
 136  * powernv_cpuidle_driver_init()
 137  */
 138 static int powernv_cpuidle_driver_init(void)
 139 {
 140         int idle_state;
 141         struct cpuidle_driver *drv = &powernv_idle_driver;
 142
 143         drv->state_count = 0;
 144
 145         for (idle_state = 0; idle_state < max_idle_state; ++idle_state) {
 146                 /* Is the state not enabled? */
 147                 if (cpuidle_state_table[idle_state].enter == NULL)
 148                         continue;
 149
 150                 drv->states[drv->state_count] = /* structure copy */
 151                         cpuidle_state_table[idle_state];
 152
 153                 drv->state_count += 1;
 154         }
 155
 156         return 0;
 157 }
 158
 159 static int powernv_add_idle_states(void)
 160 {
 161         struct device_node *power_mgt;
 162         int nr_idle_states = 1; /* Snooze */
 163         int dt_idle_states;
 164         u32 *latency_ns, *residency_ns, *flags;
 165         int i, rc;
 166
 167         /* Currently we have snooze statically defined */
 168
 169         power_mgt = of_find_node_by_path("/ibm,opal/power-mgt");
 170         if (!power_mgt) {
 171                 pr_warn("opal: PowerMgmt Node not found\n");
 172                 goto out;
 173         }
 174
 175         /* Read values of any property to determine the num of idle states */
 176         dt_idle_states = of_property_count_u32_elems(power_mgt, "ibm,cpu-idle-state-flags");
 177         if (dt_idle_states < 0) {
 178                 pr_warn("cpuidle-powernv: no idle states found in the DT\n");
 179                 goto out;
 180         }
 181
 182         flags = kzalloc(sizeof(*flags) * dt_idle_states, GFP_KERNEL);
 183         if (of_property_read_u32_array(power_mgt,
 184                         "ibm,cpu-idle-state-flags", flags, dt_idle_states)) {
 185                 pr_warn("cpuidle-powernv : missing ibm,cpu-idle-state-flags in DT\n");
 186                 goto out_free_flags;
 187         }
 188
 189         latency_ns = kzalloc(sizeof(*latency_ns) * dt_idle_states, GFP_KERNEL);
 190         rc = of_property_read_u32_array(power_mgt,
 191                 "ibm,cpu-idle-state-latencies-ns", latency_ns, dt_idle_states);
 192         if (rc) {
 193                 pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-latencies-ns in DT\n");
 194                 goto out_free_latency;
 195         }
 196
 197         residency_ns = kzalloc(sizeof(*residency_ns) * dt_idle_states, GFP_KERNEL);
 198         rc = of_property_read_u32_array(power_mgt,
 199                 "ibm,cpu-idle-state-residency-ns", residency_ns, dt_idle_states);
 200
 201         for (i = 0; i < dt_idle_states; i++) {
 202
 203                 /*
 204                  * Cpuidle accepts exit_latency and target_residency in us.
 205                  * Use default target_residency values if f/w does not expose it.
 206                  */
 207                 if (flags[i] & OPAL_PM_NAP_ENABLED) {
 208                         /* Add NAP state */
 209                         strcpy(powernv_states[nr_idle_states].name, "Nap");
 210                         strcpy(powernv_states[nr_idle_states].desc, "Nap");
 211                         powernv_states[nr_idle_states].flags = 0;
 212                         powernv_states[nr_idle_states].target_residency = 100;
 213                         powernv_states[nr_idle_states].enter = &nap_loop;
 214                 }
 215
 216                 /*
 217                  * All cpuidle states with CPUIDLE_FLAG_TIMER_STOP set must come
 218                  * within this config dependency check.
 219                  */
 220 #ifdef CONFIG_TICK_ONESHOT
 221                 if (flags[i] & OPAL_PM_SLEEP_ENABLED ||
 222                         flags[i] & OPAL_PM_SLEEP_ENABLED_ER1) {
 223                         /* Add FASTSLEEP state */
 224                         strcpy(powernv_states[nr_idle_states].name, "FastSleep");
 225                         strcpy(powernv_states[nr_idle_states].desc, "FastSleep");
 226                         powernv_states[nr_idle_states].flags = CPUIDLE_FLAG_TIMER_STOP;
 227                         powernv_states[nr_idle_states].target_residency = 300000;
 228                         powernv_states[nr_idle_states].enter = &fastsleep_loop;
 229                 }
 230 #endif
 231                 powernv_states[nr_idle_states].exit_latency =
 232                                 ((unsigned int)latency_ns[i]) / 1000;
 233
 234                 if (!rc) {
 235                         powernv_states[nr_idle_states].target_residency =
 236                                 ((unsigned int)residency_ns[i]) / 1000;
 237                 }
 238
 239                 nr_idle_states++;
 240         }
 241
 242         kfree(residency_ns);
 243 out_free_latency:
 244         kfree(latency_ns);
 245 out_free_flags:
 246         kfree(flags);
 247 out:
 248         return nr_idle_states;
 249 }
 250
 251 /*
 252  * powernv_idle_probe()
 253  * Choose state table for shared versus dedicated partition
 254  */
 255 static int powernv_idle_probe(void)
 256 {
 257         if (cpuidle_disable != IDLE_NO_OVERRIDE)
 258                 return -ENODEV;
 259
 260         if (firmware_has_feature(FW_FEATURE_OPALv3)) {
 261                 cpuidle_state_table = powernv_states;
 262                 /* Device tree can indicate more idle states */
 263                 max_idle_state = powernv_add_idle_states();
 264         } else
 265                 return -ENODEV;
 266
 267         return 0;
 268 }
 269
 270 static int __init powernv_processor_idle_init(void)
 271 {
 272         int retval;
 273
 274         retval = powernv_idle_probe();
 275         if (retval)
 276                 return retval;
 277
 278         powernv_cpuidle_driver_init();
 279         retval = cpuidle_register(&powernv_idle_driver, NULL);
 280         if (retval) {
 281                 printk(KERN_DEBUG "Registration of powernv driver failed.\n");
 282                 return retval;
 283         }
 284
 285         register_cpu_notifier(&setup_hotplug_notifier);
 286         printk(KERN_DEBUG "powernv_idle_driver registered\n");
 287         return 0;
 288 }
 289
 290 device_initcall(powernv_processor_idle_init);