diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/cpuidle/Kconfig | 5 | ||||
| -rw-r--r-- | drivers/cpuidle/Kconfig.powerpc | 11 | ||||
| -rw-r--r-- | drivers/cpuidle/Makefile | 4 | ||||
| -rw-r--r-- | drivers/cpuidle/cpuidle-pseries.c | 361 |
4 files changed, 381 insertions, 0 deletions
diff --git a/drivers/cpuidle/Kconfig b/drivers/cpuidle/Kconfig index b3fb81d7cf04..f04e25f6c98d 100644 --- a/drivers/cpuidle/Kconfig +++ b/drivers/cpuidle/Kconfig @@ -35,6 +35,11 @@ depends on ARM source "drivers/cpuidle/Kconfig.arm" endmenu +menu "POWERPC CPU Idle Drivers" +depends on PPC +source "drivers/cpuidle/Kconfig.powerpc" +endmenu + endif config ARCH_NEEDS_CPU_IDLE_COUPLED diff --git a/drivers/cpuidle/Kconfig.powerpc b/drivers/cpuidle/Kconfig.powerpc new file mode 100644 index 000000000000..8147de522a96 --- /dev/null +++ b/drivers/cpuidle/Kconfig.powerpc @@ -0,0 +1,11 @@ +# +# POWERPC CPU Idle Drivers +# +config PSERIES_CPUIDLE + bool "Cpuidle driver for pSeries platforms" + depends on CPU_IDLE + depends on PPC_PSERIES + default y + help + Select this option to enable processor idle state management + through cpuidle subsystem. diff --git a/drivers/cpuidle/Makefile b/drivers/cpuidle/Makefile index 527be28e5c1e..a6331ad32738 100644 --- a/drivers/cpuidle/Makefile +++ b/drivers/cpuidle/Makefile @@ -13,3 +13,7 @@ obj-$(CONFIG_ARM_KIRKWOOD_CPUIDLE) += cpuidle-kirkwood.o obj-$(CONFIG_ARM_ZYNQ_CPUIDLE) += cpuidle-zynq.o obj-$(CONFIG_ARM_U8500_CPUIDLE) += cpuidle-ux500.o obj-$(CONFIG_ARM_AT91_CPUIDLE) += cpuidle-at91.o + +############################################################################### +# POWERPC drivers +obj-$(CONFIG_PSERIES_CPUIDLE) += cpuidle-pseries.o diff --git a/drivers/cpuidle/cpuidle-pseries.c b/drivers/cpuidle/cpuidle-pseries.c new file mode 100644 index 000000000000..21154782402a --- /dev/null +++ b/drivers/cpuidle/cpuidle-pseries.c @@ -0,0 +1,361 @@ +/* + * cpuidle-pseries - 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/plpar_wrappers.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) +{ + u64 wait_cycles; + + wait_cycles = be64_to_cpu(get_lppaca()->wait_state_cycles); + wait_cycles += mfspr(SPRN_PURR) - in_purr; + get_lppaca()->wait_state_cycles = cpu_to_be64(wait_cycles); + 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)) { + 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; + + 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"); |