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403 lines
10 KiB
403 lines
10 KiB
// 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 default_snooze_timeout __read_mostly; |
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static bool snooze_timeout_en __read_mostly; |
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static u64 get_snooze_timeout(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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int i; |
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if (unlikely(!snooze_timeout_en)) |
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return default_snooze_timeout; |
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for (i = index + 1; i < drv->state_count; i++) { |
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if (dev->states_usage[i].disable) |
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continue; |
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return drv->states[i].target_residency * tb_ticks_per_usec; |
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} |
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return default_snooze_timeout; |
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} |
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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() + get_snooze_timeout(dev, drv, index); |
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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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local_irq_disable(); |
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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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arch300_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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/* For power8 and below psscr_* will be 0 */ |
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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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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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int nr_idle_states = 1; /* Snooze */ |
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int dt_idle_states; |
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u32 has_stop_states = 0; |
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int i; |
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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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if (nr_pnv_idle_states <= 0) { |
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pr_warn("cpuidle-powernv : Only Snooze is available\n"); |
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goto out; |
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} |
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/* TODO: Count only states which are eligible for cpuidle */ |
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dt_idle_states = nr_pnv_idle_states; |
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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 (nr_pnv_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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/* |
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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 = (pnv_idle_states[0].flags & |
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(OPAL_PM_STOP_INST_FAST | OPAL_PM_STOP_INST_DEEP)); |
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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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struct pnv_idle_states_t *state = &pnv_idle_states[i]; |
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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 ((state->flags & supported_flags) != state->flags) |
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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 (state->latency_ns > 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(state->latency_ns, 1000); |
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target_residency = DIV_ROUND_UP(state->residency_ns, 1000); |
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if (has_stop_states && !(state->valid)) |
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continue; |
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if (state->flags & OPAL_PM_TIMEBASE_STOP) |
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stops_timebase = true; |
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if (state->flags & OPAL_PM_NAP_ENABLED) { |
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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, state->name, |
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CPUIDLE_FLAG_NONE, stop_loop, |
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target_residency, exit_latency, |
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state->psscr_val, |
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state->psscr_mask); |
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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 (state->flags & OPAL_PM_SLEEP_ENABLED || |
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state->flags & OPAL_PM_SLEEP_ENABLED_ER1) { |
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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, state->name, |
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CPUIDLE_FLAG_TIMER_STOP, stop_loop, |
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target_residency, exit_latency, |
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state->psscr_val, |
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state->psscr_mask); |
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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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default_snooze_timeout = TICK_USEC * tb_ticks_per_usec; |
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if (max_idle_state > 1) |
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snooze_timeout_en = true; |
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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, |
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"cpuidle/powernv:dead", NULL, |
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powernv_cpuidle_cpu_dead); |
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WARN_ON(retval < 0); |
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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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