/* * 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 <linux/slab.h> #include <asm/machdep.h> #include <asm/firmware.h> #include <asm/opal.h> #include <asm/runlatch.h> #define POWERNV_THRESHOLD_LATENCY_NS 200000 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 u64 stop_psscr_table[CPUIDLE_STATE_MAX]; static u64 snooze_timeout; static bool snooze_timeout_en; static int snooze_loop(struct cpuidle_device *dev, struct cpuidle_driver *drv, int index) { u64 snooze_exit_time; local_irq_enable(); set_thread_flag(TIF_POLLING_NRFLAG); snooze_exit_time = get_tb() + snooze_timeout; ppc64_runlatch_off(); while (!need_resched()) { HMT_low(); HMT_very_low(); if (snooze_timeout_en && get_tb() > snooze_exit_time) break; } 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; } /* Register for fastsleep only in oneshot mode of broadcast */ #ifdef CONFIG_TICK_ONESHOT 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; } #endif static int stop_loop(struct cpuidle_device *dev, struct cpuidle_driver *drv, int index) { ppc64_runlatch_off(); power9_idle_stop(stop_psscr_table[index]); ppc64_runlatch_on(); return index; } /* * States for dedicated partition case. */ static struct cpuidle_state powernv_states[CPUIDLE_STATE_MAX] = { { /* Snooze */ .name = "snooze", .desc = "snooze", .exit_latency = 0, .target_residency = 0, .enter = snooze_loop }, }; static int powernv_cpuidle_cpu_online(unsigned int cpu) { struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu); if (dev && cpuidle_get_driver()) { cpuidle_pause_and_lock(); cpuidle_enable_device(dev); cpuidle_resume_and_unlock(); } return 0; } static int powernv_cpuidle_cpu_dead(unsigned int cpu) { struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu); if (dev && cpuidle_get_driver()) { cpuidle_pause_and_lock(); cpuidle_disable_device(dev); cpuidle_resume_and_unlock(); } return 0; } /* * 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; u32 latency_ns[CPUIDLE_STATE_MAX]; u32 residency_ns[CPUIDLE_STATE_MAX]; u32 flags[CPUIDLE_STATE_MAX]; u64 psscr_val[CPUIDLE_STATE_MAX]; const char *names[CPUIDLE_STATE_MAX]; int i, rc; /* 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"); goto out; } /* Read values of any property to determine the num of idle states */ dt_idle_states = of_property_count_u32_elems(power_mgt, "ibm,cpu-idle-state-flags"); if (dt_idle_states < 0) { pr_warn("cpuidle-powernv: no idle states found in the DT\n"); goto out; } /* * Since snooze is used as first idle state, max idle states allowed is * CPUIDLE_STATE_MAX -1 */ if (dt_idle_states > CPUIDLE_STATE_MAX - 1) { pr_warn("cpuidle-powernv: discovered idle states more than allowed"); dt_idle_states = CPUIDLE_STATE_MAX - 1; } if (of_property_read_u32_array(power_mgt, "ibm,cpu-idle-state-flags", flags, dt_idle_states)) { pr_warn("cpuidle-powernv : missing ibm,cpu-idle-state-flags in DT\n"); goto out; } if (of_property_read_u32_array(power_mgt, "ibm,cpu-idle-state-latencies-ns", latency_ns, dt_idle_states)) { pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-latencies-ns in DT\n"); goto out; } if (of_property_read_string_array(power_mgt, "ibm,cpu-idle-state-names", names, dt_idle_states) < 0) { pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-names in DT\n"); goto out; } /* * If the idle states use stop instruction, probe for psscr values * which are necessary to specify required stop level. */ if (flags[0] & (OPAL_PM_STOP_INST_FAST | OPAL_PM_STOP_INST_DEEP)) if (of_property_read_u64_array(power_mgt, "ibm,cpu-idle-state-psscr", psscr_val, dt_idle_states)) { pr_warn("cpuidle-powernv: missing ibm,cpu-idle-states-psscr in DT\n"); goto out; } rc = of_property_read_u32_array(power_mgt, "ibm,cpu-idle-state-residency-ns", residency_ns, dt_idle_states); for (i = 0; i < dt_idle_states; i++) { /* * If an idle state has exit latency beyond * POWERNV_THRESHOLD_LATENCY_NS then don't use it * in cpu-idle. */ if (latency_ns[i] > POWERNV_THRESHOLD_LATENCY_NS) continue; /* * Cpuidle accepts exit_latency and target_residency in us. * Use default target_residency values if f/w does not expose it. */ if (flags[i] & OPAL_PM_NAP_ENABLED) { /* 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 = 0; powernv_states[nr_idle_states].target_residency = 100; powernv_states[nr_idle_states].enter = nap_loop; } else if ((flags[i] & OPAL_PM_STOP_INST_FAST) && !(flags[i] & OPAL_PM_TIMEBASE_STOP)) { strncpy(powernv_states[nr_idle_states].name, names[i], CPUIDLE_NAME_LEN); strncpy(powernv_states[nr_idle_states].desc, names[i], CPUIDLE_NAME_LEN); powernv_states[nr_idle_states].flags = 0; powernv_states[nr_idle_states].enter = stop_loop; stop_psscr_table[nr_idle_states] = psscr_val[i]; } /* * All cpuidle states with CPUIDLE_FLAG_TIMER_STOP set must come * within this config dependency check. */ #ifdef CONFIG_TICK_ONESHOT if (flags[i] & OPAL_PM_SLEEP_ENABLED || flags[i] & OPAL_PM_SLEEP_ENABLED_ER1) { /* 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_TIMER_STOP; powernv_states[nr_idle_states].target_residency = 300000; powernv_states[nr_idle_states].enter = fastsleep_loop; } else if ((flags[i] & OPAL_PM_STOP_INST_DEEP) && (flags[i] & OPAL_PM_TIMEBASE_STOP)) { strncpy(powernv_states[nr_idle_states].name, names[i], CPUIDLE_NAME_LEN); strncpy(powernv_states[nr_idle_states].desc, names[i], CPUIDLE_NAME_LEN); powernv_states[nr_idle_states].flags = CPUIDLE_FLAG_TIMER_STOP; powernv_states[nr_idle_states].enter = stop_loop; stop_psscr_table[nr_idle_states] = psscr_val[i]; } #endif powernv_states[nr_idle_states].exit_latency = ((unsigned int)latency_ns[i]) / 1000; if (!rc) { powernv_states[nr_idle_states].target_residency = ((unsigned int)residency_ns[i]) / 1000; } nr_idle_states++; } out: 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_OPAL)) { cpuidle_state_table = powernv_states; /* Device tree can indicate more idle states */ max_idle_state = powernv_add_idle_states(); if (max_idle_state > 1) { snooze_timeout_en = true; snooze_timeout = powernv_states[1].target_residency * tb_ticks_per_usec; } } 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; } retval = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "cpuidle/powernv:online", powernv_cpuidle_cpu_online, NULL); WARN_ON(retval < 0); retval = cpuhp_setup_state_nocalls(CPUHP_CPUIDLE_DEAD, "cpuidle/powernv:dead", NULL, powernv_cpuidle_cpu_dead); WARN_ON(retval < 0); printk(KERN_DEBUG "powernv_idle_driver registered\n"); return 0; } device_initcall(powernv_processor_idle_init);