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- /*
- * 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;
- int nr_idle_states = 1; /* Snooze */
- int dt_idle_states;
- const __be32 *idle_state_flags;
- u32 len_flags, 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;
- }
- idle_state_flags = of_get_property(power_mgt, "ibm,cpu-idle-state-flags", &len_flags);
- if (!idle_state_flags) {
- pr_warn("DT-PowerMgmt: missing ibm,cpu-idle-state-flags\n");
- return nr_idle_states;
- }
- dt_idle_states = len_flags / sizeof(u32);
- for (i = 0; i < dt_idle_states; i++) {
- flags = be32_to_cpu(idle_state_flags[i]);
- if (flags & 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 & 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);
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