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 static u64 default_snooze_timeout;
  33 static bool snooze_timeout_en;
  34
  35 static u64 get_snooze_timeout(struct cpuidle_device *dev,
  36                               struct cpuidle_driver *drv,
  37                               int index)
  38 {
  39         int i;
  40
  41         if (unlikely(!snooze_timeout_en))
  42                 return default_snooze_timeout;
  43
  44         for (i = index + 1; i < drv->state_count; i++) {
  45                 struct cpuidle_state *s = &drv->states[i];
  46                 struct cpuidle_state_usage *su = &dev->states_usage[i];
  47
  48                 if (s->disabled || su->disable)
  49                         continue;
  50
  51                 return s->target_residency * tb_ticks_per_usec;
  52         }
  53
  54         return default_snooze_timeout;
  55 }
  56
  57 static int snooze_loop(struct cpuidle_device *dev,
  58                         struct cpuidle_driver *drv,
  59                         int index)
  60 {
  61         u64 snooze_exit_time;
  62
  63         local_irq_enable();
  64         set_thread_flag(TIF_POLLING_NRFLAG);
  65
  66         snooze_exit_time = get_tb() + get_snooze_timeout(dev, drv, index);
  67         ppc64_runlatch_off();
  68         while (!need_resched()) {
  69                 HMT_low();
  70                 HMT_very_low();
  71                 if (snooze_timeout_en && get_tb() > snooze_exit_time)
  72                         break;
  73         }
  74
  75         HMT_medium();
  76         ppc64_runlatch_on();
  77         clear_thread_flag(TIF_POLLING_NRFLAG);
  78         smp_mb();
  79         return index;
  80 }
  81
  82 static int nap_loop(struct cpuidle_device *dev,
  83                         struct cpuidle_driver *drv,
  84                         int index)
  85 {
  86         ppc64_runlatch_off();
  87         power7_idle();
  88         ppc64_runlatch_on();
  89         return index;
  90 }
  91
  92 /* Register for fastsleep only in oneshot mode of broadcast */
  93 #ifdef CONFIG_TICK_ONESHOT
  94 static int fastsleep_loop(struct cpuidle_device *dev,
  95                                 struct cpuidle_driver *drv,
  96                                 int index)
  97 {
  98         unsigned long old_lpcr = mfspr(SPRN_LPCR);
  99         unsigned long new_lpcr;
 100
 101         if (unlikely(system_state < SYSTEM_RUNNING))
 102                 return index;
 103
 104         new_lpcr = old_lpcr;
 105         /* Do not exit powersave upon decrementer as we've setup the timer
 106          * offload.
 107          */
 108         new_lpcr &= ~LPCR_PECE1;
 109
 110         mtspr(SPRN_LPCR, new_lpcr);
 111         power7_sleep();
 112
 113         mtspr(SPRN_LPCR, old_lpcr);
 114
 115         return index;
 116 }
 117 #endif
 118 /*
 119  * States for dedicated partition case.
 120  */
 121 static struct cpuidle_state powernv_states[MAX_POWERNV_IDLE_STATES] = {
 122         { /* Snooze */
 123                 .name = "snooze",
 124                 .desc = "snooze",
 125                 .exit_latency = 0,
 126                 .target_residency = 0,
 127                 .enter = &snooze_loop },
 128 };
 129
 130 static int powernv_cpuidle_add_cpu_notifier(struct notifier_block *n,
 131                         unsigned long action, void *hcpu)
 132 {
 133         int hotcpu = (unsigned long)hcpu;
 134         struct cpuidle_device *dev =
 135                                 per_cpu(cpuidle_devices, hotcpu);
 136
 137         if (dev && cpuidle_get_driver()) {
 138                 switch (action) {
 139                 case CPU_ONLINE:
 140                 case CPU_ONLINE_FROZEN:
 141                         cpuidle_pause_and_lock();
 142                         cpuidle_enable_device(dev);
 143                         cpuidle_resume_and_unlock();
 144                         break;
 145
 146                 case CPU_DEAD:
 147                 case CPU_DEAD_FROZEN:
 148                         cpuidle_pause_and_lock();
 149                         cpuidle_disable_device(dev);
 150                         cpuidle_resume_and_unlock();
 151                         break;
 152
 153                 default:
 154                         return NOTIFY_DONE;
 155                 }
 156         }
 157         return NOTIFY_OK;
 158 }
 159
 160 static struct notifier_block setup_hotplug_notifier = {
 161         .notifier_call = powernv_cpuidle_add_cpu_notifier,
 162 };
 163
 164 /*
 165  * powernv_cpuidle_driver_init()
 166  */
 167 static int powernv_cpuidle_driver_init(void)
 168 {
 169         int idle_state;
 170         struct cpuidle_driver *drv = &powernv_idle_driver;
 171
 172         drv->state_count = 0;
 173
 174         for (idle_state = 0; idle_state < max_idle_state; ++idle_state) {
 175                 /* Is the state not enabled? */
 176                 if (cpuidle_state_table[idle_state].enter == NULL)
 177                         continue;
 178
 179                 drv->states[drv->state_count] = /* structure copy */
 180                         cpuidle_state_table[idle_state];
 181
 182                 drv->state_count += 1;
 183         }
 184
 185         /*
 186          * On the PowerNV platform cpu_present may be less than cpu_possible in
 187          * cases when firmware detects the CPU, but it is not available to the
 188          * OS.  If CONFIG_HOTPLUG_CPU=n, then such CPUs are not hotplugable at
 189          * run time and hence cpu_devices are not created for those CPUs by the
 190          * generic topology_init().
 191          *
 192          * drv->cpumask defaults to cpu_possible_mask in
 193          * __cpuidle_driver_init().  This breaks cpuidle on PowerNV where
 194          * cpu_devices are not created for CPUs in cpu_possible_mask that
 195          * cannot be hot-added later at run time.
 196          *
 197          * Trying cpuidle_register_device() on a CPU without a cpu_device is
 198          * incorrect, so pass a correct CPU mask to the generic cpuidle driver.
 199          */
 200
 201         drv->cpumask = (struct cpumask *)cpu_present_mask;
 202
 203         return 0;
 204 }
 205
 206 static int powernv_add_idle_states(void)
 207 {
 208         struct device_node *power_mgt;
 209         int nr_idle_states = 1; /* Snooze */
 210         int dt_idle_states;
 211         u32 *latency_ns, *residency_ns, *flags;
 212         int i, rc;
 213
 214         /* Currently we have snooze statically defined */
 215
 216         power_mgt = of_find_node_by_path("/ibm,opal/power-mgt");
 217         if (!power_mgt) {
 218                 pr_warn("opal: PowerMgmt Node not found\n");
 219                 goto out;
 220         }
 221
 222         /* Read values of any property to determine the num of idle states */
 223         dt_idle_states = of_property_count_u32_elems(power_mgt, "ibm,cpu-idle-state-flags");
 224         if (dt_idle_states < 0) {
 225                 pr_warn("cpuidle-powernv: no idle states found in the DT\n");
 226                 goto out;
 227         }
 228
 229         flags = kzalloc(sizeof(*flags) * dt_idle_states, GFP_KERNEL);
 230         if (of_property_read_u32_array(power_mgt,
 231                         "ibm,cpu-idle-state-flags", flags, dt_idle_states)) {
 232                 pr_warn("cpuidle-powernv : missing ibm,cpu-idle-state-flags in DT\n");
 233                 goto out_free_flags;
 234         }
 235
 236         latency_ns = kzalloc(sizeof(*latency_ns) * dt_idle_states, GFP_KERNEL);
 237         rc = of_property_read_u32_array(power_mgt,
 238                 "ibm,cpu-idle-state-latencies-ns", latency_ns, dt_idle_states);
 239         if (rc) {
 240                 pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-latencies-ns in DT\n");
 241                 goto out_free_latency;
 242         }
 243
 244         residency_ns = kzalloc(sizeof(*residency_ns) * dt_idle_states, GFP_KERNEL);
 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                 /*
 251                  * Cpuidle accepts exit_latency and target_residency in us.
 252                  * Use default target_residency values if f/w does not expose it.
 253                  */
 254                 if (flags[i] & OPAL_PM_NAP_ENABLED) {
 255                         /* Add NAP state */
 256                         strcpy(powernv_states[nr_idle_states].name, "Nap");
 257                         strcpy(powernv_states[nr_idle_states].desc, "Nap");
 258                         powernv_states[nr_idle_states].flags = 0;
 259                         powernv_states[nr_idle_states].target_residency = 100;
 260                         powernv_states[nr_idle_states].enter = &nap_loop;
 261                 }
 262
 263                 /*
 264                  * All cpuidle states with CPUIDLE_FLAG_TIMER_STOP set must come
 265                  * within this config dependency check.
 266                  */
 267 #ifdef CONFIG_TICK_ONESHOT
 268                 if (flags[i] & OPAL_PM_SLEEP_ENABLED ||
 269                         flags[i] & OPAL_PM_SLEEP_ENABLED_ER1) {
 270                         /* Add FASTSLEEP state */
 271                         strcpy(powernv_states[nr_idle_states].name, "FastSleep");
 272                         strcpy(powernv_states[nr_idle_states].desc, "FastSleep");
 273                         powernv_states[nr_idle_states].flags = CPUIDLE_FLAG_TIMER_STOP;
 274                         powernv_states[nr_idle_states].target_residency = 300000;
 275                         powernv_states[nr_idle_states].enter = &fastsleep_loop;
 276                 }
 277 #endif
 278                 powernv_states[nr_idle_states].exit_latency =
 279                                 ((unsigned int)latency_ns[i]) / 1000;
 280
 281                 if (!rc) {
 282                         powernv_states[nr_idle_states].target_residency =
 283                                 ((unsigned int)residency_ns[i]) / 1000;
 284                 }
 285
 286                 nr_idle_states++;
 287         }
 288
 289         kfree(residency_ns);
 290 out_free_latency:
 291         kfree(latency_ns);
 292 out_free_flags:
 293         kfree(flags);
 294 out:
 295         return nr_idle_states;
 296 }
 297
 298 /*
 299  * powernv_idle_probe()
 300  * Choose state table for shared versus dedicated partition
 301  */
 302 static int powernv_idle_probe(void)
 303 {
 304         if (cpuidle_disable != IDLE_NO_OVERRIDE)
 305                 return -ENODEV;
 306
 307         if (firmware_has_feature(FW_FEATURE_OPAL)) {
 308                 cpuidle_state_table = powernv_states;
 309                 /* Device tree can indicate more idle states */
 310                 max_idle_state = powernv_add_idle_states();
 311                 default_snooze_timeout = TICK_USEC * tb_ticks_per_usec;
 312                 if (max_idle_state > 1)
 313                         snooze_timeout_en = true;
 314         } else
 315                 return -ENODEV;
 316
 317         return 0;
 318 }
 319
 320 static int __init powernv_processor_idle_init(void)
 321 {
 322         int retval;
 323
 324         retval = powernv_idle_probe();
 325         if (retval)
 326                 return retval;
 327
 328         powernv_cpuidle_driver_init();
 329         retval = cpuidle_register(&powernv_idle_driver, NULL);
 330         if (retval) {
 331                 printk(KERN_DEBUG "Registration of powernv driver failed.\n");
 332                 return retval;
 333         }
 334
 335         register_cpu_notifier(&setup_hotplug_notifier);
 336         printk(KERN_DEBUG "powernv_idle_driver registered\n");
 337         return 0;
 338 }
 339
 340 device_initcall(powernv_processor_idle_init);