| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * 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> |
| #include <asm/cpuidle.h> |
| |
| /* |
| * Expose only those Hardware idle states via the cpuidle framework |
| * that have latency value below POWERNV_THRESHOLD_LATENCY_NS. |
| */ |
| #define POWERNV_THRESHOLD_LATENCY_NS 200000 |
| |
| static struct cpuidle_driver powernv_idle_driver = { |
| .name = "powernv_idle", |
| .owner = THIS_MODULE, |
| }; |
| |
| static int max_idle_state __read_mostly; |
| static struct cpuidle_state *cpuidle_state_table __read_mostly; |
| |
| struct stop_psscr_table { |
| u64 val; |
| u64 mask; |
| }; |
| |
| static struct stop_psscr_table stop_psscr_table[CPUIDLE_STATE_MAX] __read_mostly; |
| |
| static u64 default_snooze_timeout __read_mostly; |
| static bool snooze_timeout_en __read_mostly; |
| |
| static u64 get_snooze_timeout(struct cpuidle_device *dev, |
| struct cpuidle_driver *drv, |
| int index) |
| { |
| int i; |
| |
| if (unlikely(!snooze_timeout_en)) |
| return default_snooze_timeout; |
| |
| for (i = index + 1; i < drv->state_count; i++) { |
| if (dev->states_usage[i].disable) |
| continue; |
| |
| return drv->states[i].target_residency * tb_ticks_per_usec; |
| } |
| |
| return default_snooze_timeout; |
| } |
| |
| static int snooze_loop(struct cpuidle_device *dev, |
| struct cpuidle_driver *drv, |
| int index) |
| { |
| u64 snooze_exit_time; |
| |
| set_thread_flag(TIF_POLLING_NRFLAG); |
| |
| local_irq_enable(); |
| |
| snooze_exit_time = get_tb() + get_snooze_timeout(dev, drv, index); |
| ppc64_runlatch_off(); |
| HMT_very_low(); |
| while (!need_resched()) { |
| if (likely(snooze_timeout_en) && get_tb() > snooze_exit_time) { |
| /* |
| * Task has not woken up but we are exiting the polling |
| * loop anyway. Require a barrier after polling is |
| * cleared to order subsequent test of need_resched(). |
| */ |
| clear_thread_flag(TIF_POLLING_NRFLAG); |
| smp_mb(); |
| break; |
| } |
| } |
| |
| HMT_medium(); |
| ppc64_runlatch_on(); |
| clear_thread_flag(TIF_POLLING_NRFLAG); |
| |
| local_irq_disable(); |
| |
| return index; |
| } |
| |
| static int nap_loop(struct cpuidle_device *dev, |
| struct cpuidle_driver *drv, |
| int index) |
| { |
| power7_idle_type(PNV_THREAD_NAP); |
| |
| 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_idle_type(PNV_THREAD_SLEEP); |
| |
| mtspr(SPRN_LPCR, old_lpcr); |
| |
| return index; |
| } |
| #endif |
| |
| static int stop_loop(struct cpuidle_device *dev, |
| struct cpuidle_driver *drv, |
| int index) |
| { |
| arch300_idle_type(stop_psscr_table[index].val, |
| stop_psscr_table[index].mask); |
| 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; |
| } |
| |
| /* |
| * On the PowerNV platform cpu_present may be less than cpu_possible in |
| * cases when firmware detects the CPU, but it is not available to the |
| * OS. If CONFIG_HOTPLUG_CPU=n, then such CPUs are not hotplugable at |
| * run time and hence cpu_devices are not created for those CPUs by the |
| * generic topology_init(). |
| * |
| * drv->cpumask defaults to cpu_possible_mask in |
| * __cpuidle_driver_init(). This breaks cpuidle on PowerNV where |
| * cpu_devices are not created for CPUs in cpu_possible_mask that |
| * cannot be hot-added later at run time. |
| * |
| * Trying cpuidle_register_device() on a CPU without a cpu_device is |
| * incorrect, so pass a correct CPU mask to the generic cpuidle driver. |
| */ |
| |
| drv->cpumask = (struct cpumask *)cpu_present_mask; |
| |
| return 0; |
| } |
| |
| static inline void add_powernv_state(int index, const char *name, |
| unsigned int flags, |
| int (*idle_fn)(struct cpuidle_device *, |
| struct cpuidle_driver *, |
| int), |
| unsigned int target_residency, |
| unsigned int exit_latency, |
| u64 psscr_val, u64 psscr_mask) |
| { |
| strscpy(powernv_states[index].name, name, CPUIDLE_NAME_LEN); |
| strscpy(powernv_states[index].desc, name, CPUIDLE_NAME_LEN); |
| powernv_states[index].flags = flags; |
| powernv_states[index].target_residency = target_residency; |
| powernv_states[index].exit_latency = exit_latency; |
| powernv_states[index].enter = idle_fn; |
| /* For power8 and below psscr_* will be 0 */ |
| stop_psscr_table[index].val = psscr_val; |
| stop_psscr_table[index].mask = psscr_mask; |
| } |
| |
| extern u32 pnv_get_supported_cpuidle_states(void); |
| static int powernv_add_idle_states(void) |
| { |
| int nr_idle_states = 1; /* Snooze */ |
| int dt_idle_states; |
| u32 has_stop_states = 0; |
| int i; |
| u32 supported_flags = pnv_get_supported_cpuidle_states(); |
| |
| |
| /* Currently we have snooze statically defined */ |
| if (nr_pnv_idle_states <= 0) { |
| pr_warn("cpuidle-powernv : Only Snooze is available\n"); |
| goto out; |
| } |
| |
| /* TODO: Count only states which are eligible for cpuidle */ |
| dt_idle_states = nr_pnv_idle_states; |
| |
| /* |
| * Since snooze is used as first idle state, max idle states allowed is |
| * CPUIDLE_STATE_MAX -1 |
| */ |
| if (nr_pnv_idle_states > CPUIDLE_STATE_MAX - 1) { |
| pr_warn("cpuidle-powernv: discovered idle states more than allowed"); |
| dt_idle_states = CPUIDLE_STATE_MAX - 1; |
| } |
| |
| /* |
| * If the idle states use stop instruction, probe for psscr values |
| * and psscr mask which are necessary to specify required stop level. |
| */ |
| has_stop_states = (pnv_idle_states[0].flags & |
| (OPAL_PM_STOP_INST_FAST | OPAL_PM_STOP_INST_DEEP)); |
| |
| for (i = 0; i < dt_idle_states; i++) { |
| unsigned int exit_latency, target_residency; |
| bool stops_timebase = false; |
| struct pnv_idle_states_t *state = &pnv_idle_states[i]; |
| |
| /* |
| * Skip the platform idle state whose flag isn't in |
| * the supported_cpuidle_states flag mask. |
| */ |
| if ((state->flags & supported_flags) != state->flags) |
| continue; |
| /* |
| * If an idle state has exit latency beyond |
| * POWERNV_THRESHOLD_LATENCY_NS then don't use it |
| * in cpu-idle. |
| */ |
| if (state->latency_ns > POWERNV_THRESHOLD_LATENCY_NS) |
| continue; |
| /* |
| * Firmware passes residency and latency values in ns. |
| * cpuidle expects it in us. |
| */ |
| exit_latency = DIV_ROUND_UP(state->latency_ns, 1000); |
| target_residency = DIV_ROUND_UP(state->residency_ns, 1000); |
| |
| if (has_stop_states && !(state->valid)) |
| continue; |
| |
| if (state->flags & OPAL_PM_TIMEBASE_STOP) |
| stops_timebase = true; |
| |
| if (state->flags & OPAL_PM_NAP_ENABLED) { |
| /* Add NAP state */ |
| add_powernv_state(nr_idle_states, "Nap", |
| CPUIDLE_FLAG_NONE, nap_loop, |
| target_residency, exit_latency, 0, 0); |
| } else if (has_stop_states && !stops_timebase) { |
| add_powernv_state(nr_idle_states, state->name, |
| CPUIDLE_FLAG_NONE, stop_loop, |
| target_residency, exit_latency, |
| state->psscr_val, |
| state->psscr_mask); |
| } |
| |
| /* |
| * All cpuidle states with CPUIDLE_FLAG_TIMER_STOP set must come |
| * within this config dependency check. |
| */ |
| #ifdef CONFIG_TICK_ONESHOT |
| else if (state->flags & OPAL_PM_SLEEP_ENABLED || |
| state->flags & OPAL_PM_SLEEP_ENABLED_ER1) { |
| /* Add FASTSLEEP state */ |
| add_powernv_state(nr_idle_states, "FastSleep", |
| CPUIDLE_FLAG_TIMER_STOP, |
| fastsleep_loop, |
| target_residency, exit_latency, 0, 0); |
| } else if (has_stop_states && stops_timebase) { |
| add_powernv_state(nr_idle_states, state->name, |
| CPUIDLE_FLAG_TIMER_STOP, stop_loop, |
| target_residency, exit_latency, |
| state->psscr_val, |
| state->psscr_mask); |
| } |
| #endif |
| else |
| continue; |
| 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(); |
| default_snooze_timeout = TICK_USEC * tb_ticks_per_usec; |
| if (max_idle_state > 1) |
| snooze_timeout_en = true; |
| } 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); |