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