![Michael Neuling](/assets/img/avatar_default.png)
Currently when entering fastsleep we clear all LPCR PECE bits. This patch changes it to only clear the decrementer bit (ie. PECE1), which is the only bit we really need to clear here. This is needed if we want to set other wakeup causes like the PECEDH bit so we can use hypervisor doorbells on powernv. Also we no longer clear the MER bit as it should never be set in the host anyway. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
255 lines
5.7 KiB
C
255 lines
5.7 KiB
C
/*
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* cpuidle-powernv - idle state cpuidle driver.
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* Adapted from drivers/cpuidle/cpuidle-pseries
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*
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/moduleparam.h>
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#include <linux/cpuidle.h>
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#include <linux/cpu.h>
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#include <linux/notifier.h>
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#include <linux/clockchips.h>
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#include <linux/of.h>
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#include <asm/machdep.h>
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#include <asm/firmware.h>
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#include <asm/runlatch.h>
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/* Flags and constants used in PowerNV platform */
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#define MAX_POWERNV_IDLE_STATES 8
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#define IDLE_USE_INST_NAP 0x00010000 /* Use nap instruction */
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#define IDLE_USE_INST_SLEEP 0x00020000 /* Use sleep instruction */
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struct cpuidle_driver powernv_idle_driver = {
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.name = "powernv_idle",
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.owner = THIS_MODULE,
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};
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static int max_idle_state;
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static struct cpuidle_state *cpuidle_state_table;
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static int snooze_loop(struct cpuidle_device *dev,
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struct cpuidle_driver *drv,
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int index)
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{
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local_irq_enable();
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set_thread_flag(TIF_POLLING_NRFLAG);
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ppc64_runlatch_off();
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while (!need_resched()) {
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HMT_low();
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HMT_very_low();
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}
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HMT_medium();
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ppc64_runlatch_on();
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clear_thread_flag(TIF_POLLING_NRFLAG);
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smp_mb();
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return index;
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}
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static int nap_loop(struct cpuidle_device *dev,
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struct cpuidle_driver *drv,
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int index)
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{
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ppc64_runlatch_off();
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power7_idle();
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ppc64_runlatch_on();
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return index;
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}
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static int fastsleep_loop(struct cpuidle_device *dev,
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struct cpuidle_driver *drv,
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int index)
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{
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unsigned long old_lpcr = mfspr(SPRN_LPCR);
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unsigned long new_lpcr;
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if (unlikely(system_state < SYSTEM_RUNNING))
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return index;
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new_lpcr = old_lpcr;
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/* Do not exit powersave upon decrementer as we've setup the timer
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* offload.
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*/
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new_lpcr &= ~LPCR_PECE1;
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mtspr(SPRN_LPCR, new_lpcr);
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power7_sleep();
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mtspr(SPRN_LPCR, old_lpcr);
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return index;
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}
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/*
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* States for dedicated partition case.
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*/
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static struct cpuidle_state powernv_states[MAX_POWERNV_IDLE_STATES] = {
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{ /* Snooze */
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.name = "snooze",
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.desc = "snooze",
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.flags = CPUIDLE_FLAG_TIME_VALID,
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.exit_latency = 0,
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.target_residency = 0,
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.enter = &snooze_loop },
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};
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static int powernv_cpuidle_add_cpu_notifier(struct notifier_block *n,
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unsigned long action, void *hcpu)
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{
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int hotcpu = (unsigned long)hcpu;
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struct cpuidle_device *dev =
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per_cpu(cpuidle_devices, hotcpu);
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if (dev && cpuidle_get_driver()) {
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switch (action) {
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case CPU_ONLINE:
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case CPU_ONLINE_FROZEN:
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cpuidle_pause_and_lock();
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cpuidle_enable_device(dev);
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cpuidle_resume_and_unlock();
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break;
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case CPU_DEAD:
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case CPU_DEAD_FROZEN:
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cpuidle_pause_and_lock();
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cpuidle_disable_device(dev);
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cpuidle_resume_and_unlock();
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break;
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default:
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return NOTIFY_DONE;
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}
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}
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return NOTIFY_OK;
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}
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static struct notifier_block setup_hotplug_notifier = {
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.notifier_call = powernv_cpuidle_add_cpu_notifier,
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};
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/*
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* powernv_cpuidle_driver_init()
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*/
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static int powernv_cpuidle_driver_init(void)
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{
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int idle_state;
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struct cpuidle_driver *drv = &powernv_idle_driver;
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drv->state_count = 0;
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for (idle_state = 0; idle_state < max_idle_state; ++idle_state) {
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/* Is the state not enabled? */
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if (cpuidle_state_table[idle_state].enter == NULL)
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continue;
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drv->states[drv->state_count] = /* structure copy */
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cpuidle_state_table[idle_state];
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drv->state_count += 1;
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}
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return 0;
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}
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static int powernv_add_idle_states(void)
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{
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struct device_node *power_mgt;
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struct property *prop;
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int nr_idle_states = 1; /* Snooze */
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int dt_idle_states;
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u32 *flags;
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int i;
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/* Currently we have snooze statically defined */
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power_mgt = of_find_node_by_path("/ibm,opal/power-mgt");
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if (!power_mgt) {
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pr_warn("opal: PowerMgmt Node not found\n");
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return nr_idle_states;
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}
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prop = of_find_property(power_mgt, "ibm,cpu-idle-state-flags", NULL);
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if (!prop) {
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pr_warn("DT-PowerMgmt: missing ibm,cpu-idle-state-flags\n");
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return nr_idle_states;
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}
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dt_idle_states = prop->length / sizeof(u32);
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flags = (u32 *) prop->value;
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for (i = 0; i < dt_idle_states; i++) {
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if (flags[i] & IDLE_USE_INST_NAP) {
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/* Add NAP state */
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strcpy(powernv_states[nr_idle_states].name, "Nap");
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strcpy(powernv_states[nr_idle_states].desc, "Nap");
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powernv_states[nr_idle_states].flags = CPUIDLE_FLAG_TIME_VALID;
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powernv_states[nr_idle_states].exit_latency = 10;
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powernv_states[nr_idle_states].target_residency = 100;
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powernv_states[nr_idle_states].enter = &nap_loop;
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nr_idle_states++;
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}
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if (flags[i] & IDLE_USE_INST_SLEEP) {
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/* Add FASTSLEEP state */
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strcpy(powernv_states[nr_idle_states].name, "FastSleep");
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strcpy(powernv_states[nr_idle_states].desc, "FastSleep");
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powernv_states[nr_idle_states].flags =
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CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_TIMER_STOP;
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powernv_states[nr_idle_states].exit_latency = 300;
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powernv_states[nr_idle_states].target_residency = 1000000;
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powernv_states[nr_idle_states].enter = &fastsleep_loop;
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nr_idle_states++;
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}
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}
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return nr_idle_states;
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}
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/*
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* powernv_idle_probe()
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* Choose state table for shared versus dedicated partition
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*/
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static int powernv_idle_probe(void)
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{
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if (cpuidle_disable != IDLE_NO_OVERRIDE)
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return -ENODEV;
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if (firmware_has_feature(FW_FEATURE_OPALv3)) {
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cpuidle_state_table = powernv_states;
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/* Device tree can indicate more idle states */
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max_idle_state = powernv_add_idle_states();
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} else
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return -ENODEV;
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return 0;
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}
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static int __init powernv_processor_idle_init(void)
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{
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int retval;
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retval = powernv_idle_probe();
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if (retval)
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return retval;
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powernv_cpuidle_driver_init();
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retval = cpuidle_register(&powernv_idle_driver, NULL);
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if (retval) {
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printk(KERN_DEBUG "Registration of powernv driver failed.\n");
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return retval;
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}
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register_cpu_notifier(&setup_hotplug_notifier);
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printk(KERN_DEBUG "powernv_idle_driver registered\n");
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return 0;
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}
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device_initcall(powernv_processor_idle_init);
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