diff options
Diffstat (limited to 'drivers/cpuidle/cpuidle-powernv.c')
| -rw-r--r-- | drivers/cpuidle/cpuidle-powernv.c | 254 |
1 files changed, 254 insertions, 0 deletions
diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c new file mode 100644 index 00000000000..74f5788d50b --- /dev/null +++ b/drivers/cpuidle/cpuidle-powernv.c @@ -0,0 +1,254 @@ +/* + * 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 <linux/clockchips.h> +#include <linux/of.h> + +#include <asm/machdep.h> +#include <asm/firmware.h> +#include <asm/runlatch.h> + +/* Flags and constants used in PowerNV platform */ + +#define MAX_POWERNV_IDLE_STATES 8 +#define IDLE_USE_INST_NAP 0x00010000 /* Use nap instruction */ +#define IDLE_USE_INST_SLEEP 0x00020000 /* Use sleep instruction */ + +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); + + ppc64_runlatch_off(); + while (!need_resched()) { + HMT_low(); + HMT_very_low(); + } + + HMT_medium(); + ppc64_runlatch_on(); + clear_thread_flag(TIF_POLLING_NRFLAG); + smp_mb(); + return index; +} + +static int nap_loop(struct cpuidle_device *dev, + struct cpuidle_driver *drv, + int index) +{ + ppc64_runlatch_off(); + power7_idle(); + ppc64_runlatch_on(); + return index; +} + +static int fastsleep_loop(struct cpuidle_device *dev, + struct cpuidle_driver *drv, + int index) +{ + unsigned long old_lpcr = mfspr(SPRN_LPCR); + unsigned long new_lpcr; + + if (unlikely(system_state < SYSTEM_RUNNING)) + return index; + + new_lpcr = old_lpcr; + /* Do not exit powersave upon decrementer as we've setup the timer + * offload. + */ + new_lpcr &= ~LPCR_PECE1; + + mtspr(SPRN_LPCR, new_lpcr); + power7_sleep(); + + mtspr(SPRN_LPCR, old_lpcr); + + return index; +} + +/* + * States for dedicated partition case. + */ +static struct cpuidle_state powernv_states[MAX_POWERNV_IDLE_STATES] = { + { /* Snooze */ + .name = "snooze", + .desc = "snooze", + .flags = CPUIDLE_FLAG_TIME_VALID, + .exit_latency = 0, + .target_residency = 0, + .enter = &snooze_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; +} + +static int powernv_add_idle_states(void) +{ + struct device_node *power_mgt; + struct property *prop; + int nr_idle_states = 1; /* Snooze */ + int dt_idle_states; + u32 *flags; + int i; + + /* Currently we have snooze statically defined */ + + power_mgt = of_find_node_by_path("/ibm,opal/power-mgt"); + if (!power_mgt) { + pr_warn("opal: PowerMgmt Node not found\n"); + return nr_idle_states; + } + + prop = of_find_property(power_mgt, "ibm,cpu-idle-state-flags", NULL); + if (!prop) { + pr_warn("DT-PowerMgmt: missing ibm,cpu-idle-state-flags\n"); + return nr_idle_states; + } + + dt_idle_states = prop->length / sizeof(u32); + flags = (u32 *) prop->value; + + for (i = 0; i < dt_idle_states; i++) { + + if (flags[i] & IDLE_USE_INST_NAP) { + /* Add NAP state */ + strcpy(powernv_states[nr_idle_states].name, "Nap"); + strcpy(powernv_states[nr_idle_states].desc, "Nap"); + powernv_states[nr_idle_states].flags = CPUIDLE_FLAG_TIME_VALID; + powernv_states[nr_idle_states].exit_latency = 10; + powernv_states[nr_idle_states].target_residency = 100; + powernv_states[nr_idle_states].enter = &nap_loop; + nr_idle_states++; + } + + if (flags[i] & IDLE_USE_INST_SLEEP) { + /* Add FASTSLEEP state */ + strcpy(powernv_states[nr_idle_states].name, "FastSleep"); + strcpy(powernv_states[nr_idle_states].desc, "FastSleep"); + powernv_states[nr_idle_states].flags = + CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_TIMER_STOP; + powernv_states[nr_idle_states].exit_latency = 300; + powernv_states[nr_idle_states].target_residency = 1000000; + powernv_states[nr_idle_states].enter = &fastsleep_loop; + nr_idle_states++; + } + } + + return nr_idle_states; +} + +/* + * 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; + /* Device tree can indicate more idle states */ + max_idle_state = powernv_add_idle_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); |