364 lines
9.1 KiB
C
364 lines
9.1 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 <linux/slab.h>
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#include <asm/machdep.h>
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#include <asm/firmware.h>
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#include <asm/opal.h>
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#include <asm/runlatch.h>
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#define POWERNV_THRESHOLD_LATENCY_NS 200000
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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 u64 stop_psscr_table[CPUIDLE_STATE_MAX];
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static u64 snooze_timeout;
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static bool snooze_timeout_en;
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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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u64 snooze_exit_time;
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local_irq_enable();
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set_thread_flag(TIF_POLLING_NRFLAG);
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snooze_exit_time = get_tb() + snooze_timeout;
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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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if (snooze_timeout_en && get_tb() > snooze_exit_time)
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break;
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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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/* Register for fastsleep only in oneshot mode of broadcast */
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#ifdef CONFIG_TICK_ONESHOT
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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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#endif
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static int stop_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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power9_idle_stop(stop_psscr_table[index]);
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ppc64_runlatch_on();
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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[CPUIDLE_STATE_MAX] = {
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{ /* Snooze */
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.name = "snooze",
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.desc = "snooze",
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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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int nr_idle_states = 1; /* Snooze */
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int dt_idle_states;
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u32 latency_ns[CPUIDLE_STATE_MAX];
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u32 residency_ns[CPUIDLE_STATE_MAX];
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u32 flags[CPUIDLE_STATE_MAX];
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u64 psscr_val[CPUIDLE_STATE_MAX];
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const char *names[CPUIDLE_STATE_MAX];
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int i, rc;
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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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goto out;
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}
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/* Read values of any property to determine the num of idle states */
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dt_idle_states = of_property_count_u32_elems(power_mgt, "ibm,cpu-idle-state-flags");
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if (dt_idle_states < 0) {
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pr_warn("cpuidle-powernv: no idle states found in the DT\n");
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goto out;
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}
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/*
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* Since snooze is used as first idle state, max idle states allowed is
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* CPUIDLE_STATE_MAX -1
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*/
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if (dt_idle_states > CPUIDLE_STATE_MAX - 1) {
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pr_warn("cpuidle-powernv: discovered idle states more than allowed");
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dt_idle_states = CPUIDLE_STATE_MAX - 1;
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}
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if (of_property_read_u32_array(power_mgt,
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"ibm,cpu-idle-state-flags", flags, dt_idle_states)) {
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pr_warn("cpuidle-powernv : missing ibm,cpu-idle-state-flags in DT\n");
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goto out;
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}
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if (of_property_read_u32_array(power_mgt,
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"ibm,cpu-idle-state-latencies-ns", latency_ns,
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dt_idle_states)) {
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pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-latencies-ns in DT\n");
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goto out;
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}
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if (of_property_read_string_array(power_mgt,
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"ibm,cpu-idle-state-names", names, dt_idle_states) < 0) {
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pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-names in DT\n");
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goto out;
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}
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/*
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* If the idle states use stop instruction, probe for psscr values
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* which are necessary to specify required stop level.
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*/
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if (flags[0] & (OPAL_PM_STOP_INST_FAST | OPAL_PM_STOP_INST_DEEP))
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if (of_property_read_u64_array(power_mgt,
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"ibm,cpu-idle-state-psscr", psscr_val, dt_idle_states)) {
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pr_warn("cpuidle-powernv: missing ibm,cpu-idle-states-psscr in DT\n");
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goto out;
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}
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rc = of_property_read_u32_array(power_mgt,
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"ibm,cpu-idle-state-residency-ns", residency_ns, dt_idle_states);
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for (i = 0; i < dt_idle_states; i++) {
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/*
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* If an idle state has exit latency beyond
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* POWERNV_THRESHOLD_LATENCY_NS then don't use it
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* in cpu-idle.
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*/
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if (latency_ns[i] > POWERNV_THRESHOLD_LATENCY_NS)
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continue;
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/*
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* Cpuidle accepts exit_latency and target_residency in us.
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* Use default target_residency values if f/w does not expose it.
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*/
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if (flags[i] & OPAL_PM_NAP_ENABLED) {
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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 = 0;
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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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} else if ((flags[i] & OPAL_PM_STOP_INST_FAST) &&
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!(flags[i] & OPAL_PM_TIMEBASE_STOP)) {
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strncpy(powernv_states[nr_idle_states].name,
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names[i], CPUIDLE_NAME_LEN);
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strncpy(powernv_states[nr_idle_states].desc,
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names[i], CPUIDLE_NAME_LEN);
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powernv_states[nr_idle_states].flags = 0;
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powernv_states[nr_idle_states].enter = stop_loop;
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stop_psscr_table[nr_idle_states] = psscr_val[i];
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}
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/*
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* All cpuidle states with CPUIDLE_FLAG_TIMER_STOP set must come
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* within this config dependency check.
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*/
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#ifdef CONFIG_TICK_ONESHOT
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if (flags[i] & OPAL_PM_SLEEP_ENABLED ||
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flags[i] & OPAL_PM_SLEEP_ENABLED_ER1) {
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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 = CPUIDLE_FLAG_TIMER_STOP;
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powernv_states[nr_idle_states].target_residency = 300000;
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powernv_states[nr_idle_states].enter = fastsleep_loop;
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} else if ((flags[i] & OPAL_PM_STOP_INST_DEEP) &&
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(flags[i] & OPAL_PM_TIMEBASE_STOP)) {
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strncpy(powernv_states[nr_idle_states].name,
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names[i], CPUIDLE_NAME_LEN);
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strncpy(powernv_states[nr_idle_states].desc,
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names[i], CPUIDLE_NAME_LEN);
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powernv_states[nr_idle_states].flags = CPUIDLE_FLAG_TIMER_STOP;
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powernv_states[nr_idle_states].enter = stop_loop;
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stop_psscr_table[nr_idle_states] = psscr_val[i];
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}
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#endif
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powernv_states[nr_idle_states].exit_latency =
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((unsigned int)latency_ns[i]) / 1000;
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if (!rc) {
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powernv_states[nr_idle_states].target_residency =
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((unsigned int)residency_ns[i]) / 1000;
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}
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nr_idle_states++;
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}
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out:
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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_OPAL)) {
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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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if (max_idle_state > 1) {
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snooze_timeout_en = true;
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snooze_timeout = powernv_states[1].target_residency *
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tb_ticks_per_usec;
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}
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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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