505 lines
13 KiB
C
505 lines
13 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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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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#include <asm/cpuidle.h>
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/*
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* Expose only those Hardware idle states via the cpuidle framework
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* that have latency value below POWERNV_THRESHOLD_LATENCY_NS.
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*/
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#define POWERNV_THRESHOLD_LATENCY_NS 200000
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static 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 __read_mostly;
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static struct cpuidle_state *cpuidle_state_table __read_mostly;
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struct stop_psscr_table {
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u64 val;
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u64 mask;
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};
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static struct stop_psscr_table stop_psscr_table[CPUIDLE_STATE_MAX] __read_mostly;
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static u64 snooze_timeout __read_mostly;
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static bool snooze_timeout_en __read_mostly;
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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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set_thread_flag(TIF_POLLING_NRFLAG);
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local_irq_enable();
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snooze_exit_time = get_tb() + snooze_timeout;
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ppc64_runlatch_off();
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HMT_very_low();
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while (!need_resched()) {
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if (likely(snooze_timeout_en) && get_tb() > snooze_exit_time) {
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/*
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* Task has not woken up but we are exiting the polling
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* loop anyway. Require a barrier after polling is
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* cleared to order subsequent test of need_resched().
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*/
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clear_thread_flag(TIF_POLLING_NRFLAG);
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smp_mb();
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break;
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}
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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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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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power7_idle_type(PNV_THREAD_NAP);
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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_idle_type(PNV_THREAD_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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power9_idle_type(stop_psscr_table[index].val,
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stop_psscr_table[index].mask);
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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_cpu_online(unsigned int cpu)
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{
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struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu);
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if (dev && cpuidle_get_driver()) {
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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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}
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return 0;
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}
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static int powernv_cpuidle_cpu_dead(unsigned int cpu)
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{
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struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu);
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if (dev && cpuidle_get_driver()) {
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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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}
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return 0;
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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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/*
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* On the PowerNV platform cpu_present may be less than cpu_possible in
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* cases when firmware detects the CPU, but it is not available to the
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* OS. If CONFIG_HOTPLUG_CPU=n, then such CPUs are not hotplugable at
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* run time and hence cpu_devices are not created for those CPUs by the
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* generic topology_init().
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*
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* drv->cpumask defaults to cpu_possible_mask in
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* __cpuidle_driver_init(). This breaks cpuidle on PowerNV where
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* cpu_devices are not created for CPUs in cpu_possible_mask that
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* cannot be hot-added later at run time.
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*
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* Trying cpuidle_register_device() on a CPU without a cpu_device is
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* incorrect, so pass a correct CPU mask to the generic cpuidle driver.
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*/
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drv->cpumask = (struct cpumask *)cpu_present_mask;
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return 0;
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}
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static inline void add_powernv_state(int index, const char *name,
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unsigned int flags,
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int (*idle_fn)(struct cpuidle_device *,
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struct cpuidle_driver *,
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int),
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unsigned int target_residency,
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unsigned int exit_latency,
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u64 psscr_val, u64 psscr_mask)
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{
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strlcpy(powernv_states[index].name, name, CPUIDLE_NAME_LEN);
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strlcpy(powernv_states[index].desc, name, CPUIDLE_NAME_LEN);
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powernv_states[index].flags = flags;
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powernv_states[index].target_residency = target_residency;
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powernv_states[index].exit_latency = exit_latency;
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powernv_states[index].enter = idle_fn;
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stop_psscr_table[index].val = psscr_val;
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stop_psscr_table[index].mask = psscr_mask;
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}
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/*
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* Returns 0 if prop1_len == prop2_len. Else returns -1
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*/
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static inline int validate_dt_prop_sizes(const char *prop1, int prop1_len,
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const char *prop2, int prop2_len)
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{
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if (prop1_len == prop2_len)
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return 0;
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pr_warn("cpuidle-powernv: array sizes don't match for %s and %s\n",
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prop1, prop2);
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return -1;
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}
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extern u32 pnv_get_supported_cpuidle_states(void);
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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, count;
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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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u64 psscr_mask[CPUIDLE_STATE_MAX];
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const char *names[CPUIDLE_STATE_MAX];
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u32 has_stop_states = 0;
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int i, rc;
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u32 supported_flags = pnv_get_supported_cpuidle_states();
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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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count = of_property_count_u32_elems(power_mgt,
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"ibm,cpu-idle-state-latencies-ns");
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if (validate_dt_prop_sizes("ibm,cpu-idle-state-flags", dt_idle_states,
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"ibm,cpu-idle-state-latencies-ns",
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count) != 0)
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goto out;
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count = of_property_count_strings(power_mgt,
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"ibm,cpu-idle-state-names");
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if (validate_dt_prop_sizes("ibm,cpu-idle-state-flags", dt_idle_states,
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"ibm,cpu-idle-state-names",
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count) != 0)
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goto out;
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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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* and psscr mask which are necessary to specify required stop level.
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*/
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has_stop_states = (flags[0] &
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(OPAL_PM_STOP_INST_FAST | OPAL_PM_STOP_INST_DEEP));
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if (has_stop_states) {
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count = of_property_count_u64_elems(power_mgt,
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"ibm,cpu-idle-state-psscr");
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if (validate_dt_prop_sizes("ibm,cpu-idle-state-flags",
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dt_idle_states,
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"ibm,cpu-idle-state-psscr",
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count) != 0)
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goto out;
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count = of_property_count_u64_elems(power_mgt,
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"ibm,cpu-idle-state-psscr-mask");
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if (validate_dt_prop_sizes("ibm,cpu-idle-state-flags",
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dt_idle_states,
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"ibm,cpu-idle-state-psscr-mask",
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count) != 0)
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goto out;
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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-state-psscr in DT\n");
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goto out;
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}
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if (of_property_read_u64_array(power_mgt,
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"ibm,cpu-idle-state-psscr-mask",
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psscr_mask, dt_idle_states)) {
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pr_warn("cpuidle-powernv:Missing ibm,cpu-idle-state-psscr-mask in DT\n");
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goto out;
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}
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}
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count = of_property_count_u32_elems(power_mgt,
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"ibm,cpu-idle-state-residency-ns");
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if (count < 0) {
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rc = count;
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} else if (validate_dt_prop_sizes("ibm,cpu-idle-state-flags",
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dt_idle_states,
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"ibm,cpu-idle-state-residency-ns",
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count) != 0) {
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goto out;
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} else {
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rc = of_property_read_u32_array(power_mgt,
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"ibm,cpu-idle-state-residency-ns",
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residency_ns, dt_idle_states);
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}
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for (i = 0; i < dt_idle_states; i++) {
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unsigned int exit_latency, target_residency;
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bool stops_timebase = false;
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/*
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* Skip the platform idle state whose flag isn't in
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* the supported_cpuidle_states flag mask.
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*/
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if ((flags[i] & supported_flags) != flags[i])
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continue;
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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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* Firmware passes residency and latency values in ns.
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* cpuidle expects it in us.
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*/
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exit_latency = DIV_ROUND_UP(latency_ns[i], 1000);
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if (!rc)
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target_residency = DIV_ROUND_UP(residency_ns[i], 1000);
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else
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target_residency = 0;
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if (has_stop_states) {
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int err = validate_psscr_val_mask(&psscr_val[i],
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&psscr_mask[i],
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flags[i]);
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if (err) {
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report_invalid_psscr_val(psscr_val[i], err);
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continue;
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}
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}
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if (flags[i] & OPAL_PM_TIMEBASE_STOP)
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stops_timebase = true;
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/*
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* For nap and fastsleep, use default target_residency
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* 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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if (!rc)
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target_residency = 100;
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/* Add NAP state */
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add_powernv_state(nr_idle_states, "Nap",
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CPUIDLE_FLAG_NONE, nap_loop,
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target_residency, exit_latency, 0, 0);
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} else if (has_stop_states && !stops_timebase) {
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add_powernv_state(nr_idle_states, names[i],
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CPUIDLE_FLAG_NONE, stop_loop,
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target_residency, exit_latency,
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psscr_val[i], psscr_mask[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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else if (flags[i] & OPAL_PM_SLEEP_ENABLED ||
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flags[i] & OPAL_PM_SLEEP_ENABLED_ER1) {
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if (!rc)
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target_residency = 300000;
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/* Add FASTSLEEP state */
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add_powernv_state(nr_idle_states, "FastSleep",
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CPUIDLE_FLAG_TIMER_STOP,
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fastsleep_loop,
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target_residency, exit_latency, 0, 0);
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} else if (has_stop_states && stops_timebase) {
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add_powernv_state(nr_idle_states, names[i],
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CPUIDLE_FLAG_TIMER_STOP, stop_loop,
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target_residency, exit_latency,
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psscr_val[i], psscr_mask[i]);
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}
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#endif
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else
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continue;
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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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retval = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
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"cpuidle/powernv:online",
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powernv_cpuidle_cpu_online, NULL);
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WARN_ON(retval < 0);
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retval = cpuhp_setup_state_nocalls(CPUHP_CPUIDLE_DEAD,
|
|
"cpuidle/powernv:dead", NULL,
|
|
powernv_cpuidle_cpu_dead);
|
|
WARN_ON(retval < 0);
|
|
printk(KERN_DEBUG "powernv_idle_driver registered\n");
|
|
return 0;
|
|
}
|
|
|
|
device_initcall(powernv_processor_idle_init);
|