| /* |
| * processor_idle - idle state cpuidle driver. |
| * Adapted from drivers/idle/intel_idle.c and |
| * drivers/acpi/processor_idle.c |
| * |
| */ |
| |
| #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/paca.h> |
| #include <asm/reg.h> |
| #include <asm/machdep.h> |
| #include <asm/firmware.h> |
| #include <asm/runlatch.h> |
| |
| #include "plpar_wrappers.h" |
| #include "pseries.h" |
| |
| struct cpuidle_driver pseries_idle_driver = { |
| .name = "pseries_idle", |
| .owner = THIS_MODULE, |
| }; |
| |
| #define MAX_IDLE_STATE_COUNT 2 |
| |
| static int max_idle_state = MAX_IDLE_STATE_COUNT - 1; |
| static struct cpuidle_device __percpu *pseries_cpuidle_devices; |
| static struct cpuidle_state *cpuidle_state_table; |
| |
| static inline void idle_loop_prolog(unsigned long *in_purr) |
| { |
| *in_purr = mfspr(SPRN_PURR); |
| /* |
| * Indicate to the HV that we are idle. Now would be |
| * a good time to find other work to dispatch. |
| */ |
| get_lppaca()->idle = 1; |
| } |
| |
| static inline void idle_loop_epilog(unsigned long in_purr) |
| { |
| get_lppaca()->wait_state_cycles += mfspr(SPRN_PURR) - in_purr; |
| get_lppaca()->idle = 0; |
| } |
| |
| static int snooze_loop(struct cpuidle_device *dev, |
| struct cpuidle_driver *drv, |
| int index) |
| { |
| unsigned long in_purr; |
| int cpu = dev->cpu; |
| |
| idle_loop_prolog(&in_purr); |
| local_irq_enable(); |
| set_thread_flag(TIF_POLLING_NRFLAG); |
| |
| while ((!need_resched()) && cpu_online(cpu)) { |
| ppc64_runlatch_off(); |
| HMT_low(); |
| HMT_very_low(); |
| } |
| |
| HMT_medium(); |
| clear_thread_flag(TIF_POLLING_NRFLAG); |
| smp_mb(); |
| |
| idle_loop_epilog(in_purr); |
| |
| return index; |
| } |
| |
| static void check_and_cede_processor(void) |
| { |
| /* |
| * Ensure our interrupt state is properly tracked, |
| * also checks if no interrupt has occurred while we |
| * were soft-disabled |
| */ |
| if (prep_irq_for_idle()) { |
| cede_processor(); |
| #ifdef CONFIG_TRACE_IRQFLAGS |
| /* Ensure that H_CEDE returns with IRQs on */ |
| if (WARN_ON(!(mfmsr() & MSR_EE))) |
| __hard_irq_enable(); |
| #endif |
| } |
| } |
| |
| static int dedicated_cede_loop(struct cpuidle_device *dev, |
| struct cpuidle_driver *drv, |
| int index) |
| { |
| unsigned long in_purr; |
| |
| idle_loop_prolog(&in_purr); |
| get_lppaca()->donate_dedicated_cpu = 1; |
| |
| ppc64_runlatch_off(); |
| HMT_medium(); |
| check_and_cede_processor(); |
| |
| get_lppaca()->donate_dedicated_cpu = 0; |
| |
| idle_loop_epilog(in_purr); |
| |
| return index; |
| } |
| |
| static int shared_cede_loop(struct cpuidle_device *dev, |
| struct cpuidle_driver *drv, |
| int index) |
| { |
| unsigned long in_purr; |
| |
| idle_loop_prolog(&in_purr); |
| |
| /* |
| * Yield the processor to the hypervisor. We return if |
| * an external interrupt occurs (which are driven prior |
| * to returning here) or if a prod occurs from another |
| * processor. When returning here, external interrupts |
| * are enabled. |
| */ |
| check_and_cede_processor(); |
| |
| idle_loop_epilog(in_purr); |
| |
| return index; |
| } |
| |
| /* |
| * States for dedicated partition case. |
| */ |
| static struct cpuidle_state dedicated_states[MAX_IDLE_STATE_COUNT] = { |
| { /* Snooze */ |
| .name = "snooze", |
| .desc = "snooze", |
| .flags = CPUIDLE_FLAG_TIME_VALID, |
| .exit_latency = 0, |
| .target_residency = 0, |
| .enter = &snooze_loop }, |
| { /* CEDE */ |
| .name = "CEDE", |
| .desc = "CEDE", |
| .flags = CPUIDLE_FLAG_TIME_VALID, |
| .exit_latency = 10, |
| .target_residency = 100, |
| .enter = &dedicated_cede_loop }, |
| }; |
| |
| /* |
| * States for shared partition case. |
| */ |
| static struct cpuidle_state shared_states[MAX_IDLE_STATE_COUNT] = { |
| { /* Shared Cede */ |
| .name = "Shared Cede", |
| .desc = "Shared Cede", |
| .flags = CPUIDLE_FLAG_TIME_VALID, |
| .exit_latency = 0, |
| .target_residency = 0, |
| .enter = &shared_cede_loop }, |
| }; |
| |
| void update_smt_snooze_delay(int cpu, int residency) |
| { |
| struct cpuidle_driver *drv = cpuidle_get_driver(); |
| struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu); |
| |
| if (cpuidle_state_table != dedicated_states) |
| return; |
| |
| if (residency < 0) { |
| /* Disable the Nap state on that cpu */ |
| if (dev) |
| dev->states_usage[1].disable = 1; |
| } else |
| if (drv) |
| drv->states[1].target_residency = residency; |
| } |
| |
| static int pseries_cpuidle_add_cpu_notifier(struct notifier_block *n, |
| unsigned long action, void *hcpu) |
| { |
| int hotcpu = (unsigned long)hcpu; |
| struct cpuidle_device *dev = |
| per_cpu_ptr(pseries_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 = pseries_cpuidle_add_cpu_notifier, |
| }; |
| |
| /* |
| * pseries_cpuidle_driver_init() |
| */ |
| static int pseries_cpuidle_driver_init(void) |
| { |
| int idle_state; |
| struct cpuidle_driver *drv = &pseries_idle_driver; |
| |
| drv->state_count = 0; |
| |
| for (idle_state = 0; idle_state < MAX_IDLE_STATE_COUNT; ++idle_state) { |
| |
| if (idle_state > max_idle_state) |
| break; |
| |
| /* 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; |
| } |
| |
| /* pseries_idle_devices_uninit(void) |
| * unregister cpuidle devices and de-allocate memory |
| */ |
| static void pseries_idle_devices_uninit(void) |
| { |
| int i; |
| struct cpuidle_device *dev; |
| |
| for_each_possible_cpu(i) { |
| dev = per_cpu_ptr(pseries_cpuidle_devices, i); |
| cpuidle_unregister_device(dev); |
| } |
| |
| free_percpu(pseries_cpuidle_devices); |
| return; |
| } |
| |
| /* pseries_idle_devices_init() |
| * allocate, initialize and register cpuidle device |
| */ |
| static int pseries_idle_devices_init(void) |
| { |
| int i; |
| struct cpuidle_driver *drv = &pseries_idle_driver; |
| struct cpuidle_device *dev; |
| |
| pseries_cpuidle_devices = alloc_percpu(struct cpuidle_device); |
| if (pseries_cpuidle_devices == NULL) |
| return -ENOMEM; |
| |
| for_each_possible_cpu(i) { |
| dev = per_cpu_ptr(pseries_cpuidle_devices, i); |
| dev->state_count = drv->state_count; |
| dev->cpu = i; |
| if (cpuidle_register_device(dev)) { |
| printk(KERN_DEBUG \ |
| "cpuidle_register_device %d failed!\n", i); |
| return -EIO; |
| } |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * pseries_idle_probe() |
| * Choose state table for shared versus dedicated partition |
| */ |
| static int pseries_idle_probe(void) |
| { |
| |
| if (!firmware_has_feature(FW_FEATURE_SPLPAR)) |
| return -ENODEV; |
| |
| if (cpuidle_disable != IDLE_NO_OVERRIDE) |
| return -ENODEV; |
| |
| if (max_idle_state == 0) { |
| printk(KERN_DEBUG "pseries processor idle disabled.\n"); |
| return -EPERM; |
| } |
| |
| if (lppaca_shared_proc(get_lppaca())) |
| cpuidle_state_table = shared_states; |
| else |
| cpuidle_state_table = dedicated_states; |
| |
| return 0; |
| } |
| |
| static int __init pseries_processor_idle_init(void) |
| { |
| int retval; |
| |
| retval = pseries_idle_probe(); |
| if (retval) |
| return retval; |
| |
| pseries_cpuidle_driver_init(); |
| retval = cpuidle_register_driver(&pseries_idle_driver); |
| if (retval) { |
| printk(KERN_DEBUG "Registration of pseries driver failed.\n"); |
| return retval; |
| } |
| |
| retval = pseries_idle_devices_init(); |
| if (retval) { |
| pseries_idle_devices_uninit(); |
| cpuidle_unregister_driver(&pseries_idle_driver); |
| return retval; |
| } |
| |
| register_cpu_notifier(&setup_hotplug_notifier); |
| printk(KERN_DEBUG "pseries_idle_driver registered\n"); |
| |
| return 0; |
| } |
| |
| static void __exit pseries_processor_idle_exit(void) |
| { |
| |
| unregister_cpu_notifier(&setup_hotplug_notifier); |
| pseries_idle_devices_uninit(); |
| cpuidle_unregister_driver(&pseries_idle_driver); |
| |
| return; |
| } |
| |
| module_init(pseries_processor_idle_init); |
| module_exit(pseries_processor_idle_exit); |
| |
| MODULE_AUTHOR("Deepthi Dharwar <deepthi@linux.vnet.ibm.com>"); |
| MODULE_DESCRIPTION("Cpuidle driver for POWER"); |
| MODULE_LICENSE("GPL"); |