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powerpc/powernv/cpuidle: Back-end cpuidle driver for powernv platform.
Following patch ports the cpuidle framework for powernv platform and also implements a cpuidle back-end powernv idle driver calling on to power7_nap and snooze idle states. Signed-off-by: Deepthi Dharwar <[email protected]> Signed-off-by: Benjamin Herrenschmidt <[email protected]>
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/* | ||
* cpuidle-powernv - idle state cpuidle driver. | ||
* Adapted from drivers/cpuidle/cpuidle-pseries | ||
* | ||
*/ | ||
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#include <linux/kernel.h> | ||
#include <linux/module.h> | ||
#include <linux/init.h> | ||
#include <linux/moduleparam.h> | ||
#include <linux/cpuidle.h> | ||
#include <linux/cpu.h> | ||
#include <linux/notifier.h> | ||
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#include <asm/machdep.h> | ||
#include <asm/firmware.h> | ||
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struct cpuidle_driver powernv_idle_driver = { | ||
.name = "powernv_idle", | ||
.owner = THIS_MODULE, | ||
}; | ||
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static int max_idle_state; | ||
static struct cpuidle_state *cpuidle_state_table; | ||
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static int snooze_loop(struct cpuidle_device *dev, | ||
struct cpuidle_driver *drv, | ||
int index) | ||
{ | ||
local_irq_enable(); | ||
set_thread_flag(TIF_POLLING_NRFLAG); | ||
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while (!need_resched()) { | ||
HMT_low(); | ||
HMT_very_low(); | ||
} | ||
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HMT_medium(); | ||
clear_thread_flag(TIF_POLLING_NRFLAG); | ||
smp_mb(); | ||
return index; | ||
} | ||
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static int nap_loop(struct cpuidle_device *dev, | ||
struct cpuidle_driver *drv, | ||
int index) | ||
{ | ||
power7_idle(); | ||
return index; | ||
} | ||
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/* | ||
* States for dedicated partition case. | ||
*/ | ||
static struct cpuidle_state powernv_states[] = { | ||
{ /* Snooze */ | ||
.name = "snooze", | ||
.desc = "snooze", | ||
.flags = CPUIDLE_FLAG_TIME_VALID, | ||
.exit_latency = 0, | ||
.target_residency = 0, | ||
.enter = &snooze_loop }, | ||
{ /* NAP */ | ||
.name = "NAP", | ||
.desc = "NAP", | ||
.flags = CPUIDLE_FLAG_TIME_VALID, | ||
.exit_latency = 10, | ||
.target_residency = 100, | ||
.enter = &nap_loop }, | ||
}; | ||
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static int powernv_cpuidle_add_cpu_notifier(struct notifier_block *n, | ||
unsigned long action, void *hcpu) | ||
{ | ||
int hotcpu = (unsigned long)hcpu; | ||
struct cpuidle_device *dev = | ||
per_cpu(cpuidle_devices, hotcpu); | ||
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if (dev && cpuidle_get_driver()) { | ||
switch (action) { | ||
case CPU_ONLINE: | ||
case CPU_ONLINE_FROZEN: | ||
cpuidle_pause_and_lock(); | ||
cpuidle_enable_device(dev); | ||
cpuidle_resume_and_unlock(); | ||
break; | ||
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case CPU_DEAD: | ||
case CPU_DEAD_FROZEN: | ||
cpuidle_pause_and_lock(); | ||
cpuidle_disable_device(dev); | ||
cpuidle_resume_and_unlock(); | ||
break; | ||
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default: | ||
return NOTIFY_DONE; | ||
} | ||
} | ||
return NOTIFY_OK; | ||
} | ||
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static struct notifier_block setup_hotplug_notifier = { | ||
.notifier_call = powernv_cpuidle_add_cpu_notifier, | ||
}; | ||
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/* | ||
* powernv_cpuidle_driver_init() | ||
*/ | ||
static int powernv_cpuidle_driver_init(void) | ||
{ | ||
int idle_state; | ||
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) { | ||
/* Is the state not enabled? */ | ||
if (cpuidle_state_table[idle_state].enter == NULL) | ||
continue; | ||
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drv->states[drv->state_count] = /* structure copy */ | ||
cpuidle_state_table[idle_state]; | ||
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drv->state_count += 1; | ||
} | ||
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return 0; | ||
} | ||
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/* | ||
* powernv_idle_probe() | ||
* Choose state table for shared versus dedicated partition | ||
*/ | ||
static int powernv_idle_probe(void) | ||
{ | ||
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if (cpuidle_disable != IDLE_NO_OVERRIDE) | ||
return -ENODEV; | ||
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if (firmware_has_feature(FW_FEATURE_OPALv3)) { | ||
cpuidle_state_table = powernv_states; | ||
max_idle_state = ARRAY_SIZE(powernv_states); | ||
} else | ||
return -ENODEV; | ||
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return 0; | ||
} | ||
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static int __init powernv_processor_idle_init(void) | ||
{ | ||
int retval; | ||
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retval = powernv_idle_probe(); | ||
if (retval) | ||
return retval; | ||
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powernv_cpuidle_driver_init(); | ||
retval = cpuidle_register(&powernv_idle_driver, NULL); | ||
if (retval) { | ||
printk(KERN_DEBUG "Registration of powernv driver failed.\n"); | ||
return retval; | ||
} | ||
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register_cpu_notifier(&setup_hotplug_notifier); | ||
printk(KERN_DEBUG "powernv_idle_driver registered\n"); | ||
return 0; | ||
} | ||
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device_initcall(powernv_processor_idle_init); |