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author | Deepthi Dharwar <deepthi@linux.vnet.ibm.com> | 2014-01-14 11:02:40 (GMT) |
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committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2014-01-29 06:02:24 (GMT) |
commit | 2c2e6ecfd077cbae72d32568af58c4ba57826c84 (patch) | |
tree | f46be303b75ef724a47fea4d9bb58bea9e1b4e71 /drivers/cpuidle/cpuidle-powernv.c | |
parent | 3fa8cad82b94d0bed002571bd246f2299ffc876b (diff) | |
download | linux-2c2e6ecfd077cbae72d32568af58c4ba57826c84.tar.xz |
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 <deepthi@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'drivers/cpuidle/cpuidle-powernv.c')
-rw-r--r-- | drivers/cpuidle/cpuidle-powernv.c | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c new file mode 100644 index 0000000..78fd174 --- /dev/null +++ b/drivers/cpuidle/cpuidle-powernv.c @@ -0,0 +1,169 @@ +/* + * cpuidle-powernv - idle state cpuidle driver. + * Adapted from drivers/cpuidle/cpuidle-pseries + * + */ + +#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> + +#include <asm/machdep.h> +#include <asm/firmware.h> + +struct cpuidle_driver powernv_idle_driver = { + .name = "powernv_idle", + .owner = THIS_MODULE, +}; + +static int max_idle_state; +static struct cpuidle_state *cpuidle_state_table; + +static int snooze_loop(struct cpuidle_device *dev, + struct cpuidle_driver *drv, + int index) +{ + local_irq_enable(); + set_thread_flag(TIF_POLLING_NRFLAG); + + while (!need_resched()) { + HMT_low(); + HMT_very_low(); + } + + HMT_medium(); + clear_thread_flag(TIF_POLLING_NRFLAG); + smp_mb(); + return index; +} + +static int nap_loop(struct cpuidle_device *dev, + struct cpuidle_driver *drv, + int index) +{ + power7_idle(); + return index; +} + +/* + * 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 }, +}; + +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); + + 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; + + case CPU_DEAD: + case CPU_DEAD_FROZEN: + cpuidle_pause_and_lock(); + cpuidle_disable_device(dev); + cpuidle_resume_and_unlock(); + break; + + default: + return NOTIFY_DONE; + } + } + return NOTIFY_OK; +} + +static struct notifier_block setup_hotplug_notifier = { + .notifier_call = powernv_cpuidle_add_cpu_notifier, +}; + +/* + * powernv_cpuidle_driver_init() + */ +static int powernv_cpuidle_driver_init(void) +{ + int idle_state; + struct cpuidle_driver *drv = &powernv_idle_driver; + + drv->state_count = 0; + + 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; + + drv->states[drv->state_count] = /* structure copy */ + cpuidle_state_table[idle_state]; + + drv->state_count += 1; + } + + return 0; +} + +/* + * powernv_idle_probe() + * Choose state table for shared versus dedicated partition + */ +static int powernv_idle_probe(void) +{ + + if (cpuidle_disable != IDLE_NO_OVERRIDE) + return -ENODEV; + + if (firmware_has_feature(FW_FEATURE_OPALv3)) { + cpuidle_state_table = powernv_states; + max_idle_state = ARRAY_SIZE(powernv_states); + } else + return -ENODEV; + + return 0; +} + +static int __init powernv_processor_idle_init(void) +{ + int retval; + + retval = powernv_idle_probe(); + if (retval) + return retval; + + powernv_cpuidle_driver_init(); + retval = cpuidle_register(&powernv_idle_driver, NULL); + if (retval) { + printk(KERN_DEBUG "Registration of powernv driver failed.\n"); + return retval; + } + + register_cpu_notifier(&setup_hotplug_notifier); + printk(KERN_DEBUG "powernv_idle_driver registered\n"); + return 0; +} + +device_initcall(powernv_processor_idle_init); |