/* * linux/kernel/irq/manage.c * * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar * Copyright (C) 2005-2006 Thomas Gleixner * * This file contains driver APIs to the irq subsystem. */ #include #include #include #include #include #include #include #include "internals.h" #ifdef CONFIG_IRQ_FORCED_THREADING __read_mostly bool force_irqthreads; static int __init setup_forced_irqthreads(char *arg) { force_irqthreads = true; return 0; } early_param("threadirqs", setup_forced_irqthreads); #endif /** * synchronize_irq - wait for pending IRQ handlers (on other CPUs) * @irq: interrupt number to wait for * * This function waits for any pending IRQ handlers for this interrupt * to complete before returning. If you use this function while * holding a resource the IRQ handler may need you will deadlock. * * This function may be called - with care - from IRQ context. */ void synchronize_irq(unsigned int irq) { struct irq_desc *desc = irq_to_desc(irq); bool inprogress; if (!desc) return; do { unsigned long flags; /* * Wait until we're out of the critical section. This might * give the wrong answer due to the lack of memory barriers. */ while (irqd_irq_inprogress(&desc->irq_data)) cpu_relax(); /* Ok, that indicated we're done: double-check carefully. */ raw_spin_lock_irqsave(&desc->lock, flags); inprogress = irqd_irq_inprogress(&desc->irq_data); raw_spin_unlock_irqrestore(&desc->lock, flags); /* Oops, that failed? */ } while (inprogress); /* * We made sure that no hardirq handler is running. Now verify * that no threaded handlers are active. */ wait_event(desc->wait_for_threads, !atomic_read(&desc->threads_active)); } EXPORT_SYMBOL(synchronize_irq); #ifdef CONFIG_SMP cpumask_var_t irq_default_affinity; /** * irq_can_set_affinity - Check if the affinity of a given irq can be set * @irq: Interrupt to check * */ int irq_can_set_affinity(unsigned int irq) { struct irq_desc *desc = irq_to_desc(irq); if (!desc || !irqd_can_balance(&desc->irq_data) || !desc->irq_data.chip || !desc->irq_data.chip->irq_set_affinity) return 0; return 1; } /** * irq_set_thread_affinity - Notify irq threads to adjust affinity * @desc: irq descriptor which has affitnity changed * * We just set IRQTF_AFFINITY and delegate the affinity setting * to the interrupt thread itself. We can not call * set_cpus_allowed_ptr() here as we hold desc->lock and this * code can be called from hard interrupt context. */ void irq_set_thread_affinity(struct irq_desc *desc) { struct irqaction *action = desc->action; while (action) { if (action->thread) set_bit(IRQTF_AFFINITY, &action->thread_flags); action = action->next; } } #ifdef CONFIG_GENERIC_PENDING_IRQ static inline bool irq_can_move_pcntxt(struct irq_data *data) { return irqd_can_move_in_process_context(data); } static inline bool irq_move_pending(struct irq_data *data) { return irqd_is_setaffinity_pending(data); } static inline void irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask) { cpumask_copy(desc->pending_mask, mask); } static inline void irq_get_pending(struct cpumask *mask, struct irq_desc *desc) { cpumask_copy(mask, desc->pending_mask); } #else static inline bool irq_can_move_pcntxt(struct irq_data *data) { return true; } static inline bool irq_move_pending(struct irq_data *data) { return false; } static inline void irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask) { } static inline void irq_get_pending(struct cpumask *mask, struct irq_desc *desc) { } #endif int __irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask) { struct irq_chip *chip = irq_data_get_irq_chip(data); struct irq_desc *desc = irq_data_to_desc(data); int ret = 0; if (!chip || !chip->irq_set_affinity) return -EINVAL; if (irq_can_move_pcntxt(data)) { ret = chip->irq_set_affinity(data, mask, false); switch (ret) { case IRQ_SET_MASK_OK: cpumask_copy(data->affinity, mask); case IRQ_SET_MASK_OK_NOCOPY: irq_set_thread_affinity(desc); ret = 0; } } else { irqd_set_move_pending(data); irq_copy_pending(desc, mask); } if (desc->affinity_notify) { kref_get(&desc->affinity_notify->kref); schedule_work(&desc->affinity_notify->work); } irqd_set(data, IRQD_AFFINITY_SET); return ret; } /** * irq_set_affinity - Set the irq affinity of a given irq * @irq: Interrupt to set affinity * @mask: cpumask * */ int irq_set_affinity(unsigned int irq, const struct cpumask *mask) { struct irq_desc *desc = irq_to_desc(irq); unsigned long flags; int ret; if (!desc) return -EINVAL; raw_spin_lock_irqsave(&desc->lock, flags); ret = __irq_set_affinity_locked(irq_desc_get_irq_data(desc), mask); raw_spin_unlock_irqrestore(&desc->lock, flags); return ret; } int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m) { unsigned long flags; struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL); if (!desc) return -EINVAL; desc->affinity_hint = m; irq_put_desc_unlock(desc, flags); return 0; } EXPORT_SYMBOL_GPL(irq_set_affinity_hint); static void irq_affinity_notify(struct work_struct *work) { struct irq_affinity_notify *notify = container_of(work, struct irq_affinity_notify, work); struct irq_desc *desc = irq_to_desc(notify->irq); cpumask_var_t cpumask; unsigned long flags; if (!desc || !alloc_cpumask_var(&cpumask, GFP_KERNEL)) goto out; raw_spin_lock_irqsave(&desc->lock, flags); if (irq_move_pending(&desc->irq_data)) irq_get_pending(cpumask, desc); else cpumask_copy(cpumask, desc->irq_data.affinity); raw_spin_unlock_irqrestore(&desc->lock, flags); notify->notify(notify, cpumask); free_cpumask_var(cpumask); out: kref_put(¬ify->kref, notify->release); } /** * irq_set_affinity_notifier - control notification of IRQ affinity changes * @irq: Interrupt for which to enable/disable notification * @notify: Context for notification, or %NULL to disable * notification. Function pointers must be initialised; * the other fields will be initialised by this function. * * Must be called in process context. Notification may only be enabled * after the IRQ is allocated and must be disabled before the IRQ is * freed using free_irq(). */ int irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify) { struct irq_desc *desc = irq_to_desc(irq); struct irq_affinity_notify *old_notify; unsigned long flags; /* The release function is promised process context */ might_sleep(); if (!desc) return -EINVAL; /* Complete initialisation of *notify */ if (notify) { notify->irq = irq; kref_init(¬ify->kref); INIT_WORK(¬ify->work, irq_affinity_notify); } raw_spin_lock_irqsave(&desc->lock, flags); old_notify = desc->affinity_notify; desc->affinity_notify = notify; raw_spin_unlock_irqrestore(&desc->lock, flags); if (old_notify) kref_put(&old_notify->kref, old_notify->release); return 0; } EXPORT_SYMBOL_GPL(irq_set_affinity_notifier); #ifndef CONFIG_AUTO_IRQ_AFFINITY /* * Generic version of the affinity autoselector. */ static int setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask) { struct irq_chip *chip = irq_desc_get_chip(desc); struct cpumask *set = irq_default_affinity; int ret; /* Excludes PER_CPU and NO_BALANCE interrupts */ if (!irq_can_set_affinity(irq)) return 0; /* * Preserve an userspace affinity setup, but make sure that * one of the targets is online. */ if (irqd_has_set(&desc->irq_data, IRQD_AFFINITY_SET)) { if (cpumask_intersects(desc->irq_data.affinity, cpu_online_mask)) set = desc->irq_data.affinity; else irqd_clear(&desc->irq_data, IRQD_AFFINITY_SET); } cpumask_and(mask, cpu_online_mask, set); ret = chip->irq_set_affinity(&desc->irq_data, mask, false); switch (ret) { case IRQ_SET_MASK_OK: cpumask_copy(desc->irq_data.affinity, mask); case IRQ_SET_MASK_OK_NOCOPY: irq_set_thread_affinity(desc); } return 0; } #else static inline int setup_affinity(unsigned int irq, struct irq_desc *d, struct cpumask *mask) { return irq_select_affinity(irq); } #endif /* * Called when affinity is set via /proc/irq */ int irq_select_affinity_usr(unsigned int irq, struct cpumask *mask) { struct irq_desc *desc = irq_to_desc(irq); unsigned long flags; int ret; raw_spin_lock_irqsave(&desc->lock, flags); ret = setup_affinity(irq, desc, mask); raw_spin_unlock_irqrestore(&desc->lock, flags); return ret; } #else static inline int setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask) { return 0; } #endif void __disable_irq(struct irq_desc *desc, unsigned int irq, bool suspend) { if (suspend) { if (!desc->action || (desc->action->flags & IRQF_NO_SUSPEND)) return; desc->istate |= IRQS_SUSPENDED; } if (!desc->depth++) irq_disable(desc); } static int __disable_irq_nosync(unsigned int irq) { unsigned long flags; struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL); if (!desc) return -EINVAL; __disable_irq(desc, irq, false); irq_put_desc_busunlock(desc, flags); return 0; } /** * disable_irq_nosync - disable an irq without waiting * @irq: Interrupt to disable * * Disable the selected interrupt line. Disables and Enables are * nested. * Unlike disable_irq(), this function does not ensure existing * instances of the IRQ handler have completed before returning. * * This function may be called from IRQ context. */ void disable_irq_nosync(unsigned int irq) { __disable_irq_nosync(irq); } EXPORT_SYMBOL(disable_irq_nosync); /** * disable_irq - disable an irq and wait for completion * @irq: Interrupt to disable * * Disable the selected interrupt line. Enables and Disables are * nested. * This function waits for any pending IRQ handlers for this interrupt * to complete before returning. If you use this function while * holding a resource the IRQ handler may need you will deadlock. * * This function may be called - with care - from IRQ context. */ void disable_irq(unsigned int irq) { if (!__disable_irq_nosync(irq)) synchronize_irq(irq); } EXPORT_SYMBOL(disable_irq); void __enable_irq(struct irq_desc *desc, unsigned int irq, bool resume) { if (resume) { if (!(desc->istate & IRQS_SUSPENDED)) { if (!desc->action) return; if (!(desc->action->flags & IRQF_FORCE_RESUME)) return; /* Pretend that it got disabled ! */ desc->depth++; } desc->istate &= ~IRQS_SUSPENDED; } switch (desc->depth) { case 0: err_out: WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq); break; case 1: { if (desc->istate & IRQS_SUSPENDED) goto err_out; /* Prevent probing on this irq: */ irq_settings_set_noprobe(desc); irq_enable(desc); check_irq_resend(desc, irq); /* fall-through */ } default: desc->depth--; } } /** * enable_irq - enable handling of an irq * @irq: Interrupt to enable * * Undoes the effect of one call to disable_irq(). If this * matches the last disable, processing of interrupts on this * IRQ line is re-enabled. * * This function may be called from IRQ context only when * desc->irq_data.chip->bus_lock and desc->chip->bus_sync_unlock are NULL ! */ void enable_irq(unsigned int irq) { unsigned long flags; struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL); if (!desc) return; if (WARN(!desc->irq_data.chip, KERN_ERR "enable_irq before setup/request_irq: irq %u\n", irq)) goto out; __enable_irq(desc, irq, false); out: irq_put_desc_busunlock(desc, flags); } EXPORT_SYMBOL(enable_irq); static int set_irq_wake_real(unsigned int irq, unsigned int on) { struct irq_desc *desc = irq_to_desc(irq); int ret = -ENXIO; if (irq_desc_get_chip(desc)->flags & IRQCHIP_SKIP_SET_WAKE) return 0; if (desc->irq_data.chip->irq_set_wake) ret = desc->irq_data.chip->irq_set_wake(&desc->irq_data, on); return ret; } /** * irq_set_irq_wake - control irq power management wakeup * @irq: interrupt to control * @on: enable/disable power management wakeup * * Enable/disable power management wakeup mode, which is * disabled by default. Enables and disables must match, * just as they match for non-wakeup mode support. * * Wakeup mode lets this IRQ wake the system from sleep * states like "suspend to RAM". */ int irq_set_irq_wake(unsigned int irq, unsigned int on) { unsigned long flags; struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL); int ret = 0; if (!desc) return -EINVAL; /* wakeup-capable irqs can be shared between drivers that * don't need to have the same sleep mode behaviors. */ if (on) { if (desc->wake_depth++ == 0) { ret = set_irq_wake_real(irq, on); if (ret) desc->wake_depth = 0; else irqd_set(&desc->irq_data, IRQD_WAKEUP_STATE); } } else { if (desc->wake_depth == 0) { WARN(1, "Unbalanced IRQ %d wake disable\n", irq); } else if (--desc->wake_depth == 0) { ret = set_irq_wake_real(irq, on); if (ret) desc->wake_depth = 1; else irqd_clear(&desc->irq_data, IRQD_WAKEUP_STATE); } } irq_put_desc_busunlock(desc, flags); return ret; } EXPORT_SYMBOL(irq_set_irq_wake); /* * Internal function that tells the architecture code whether a * particular irq has been exclusively allocated or is available * for driver use. */ int can_request_irq(unsigned int irq, unsigned long irqflags) { unsigned long flags; struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0); int canrequest = 0; if (!desc) return 0; if (irq_settings_can_request(desc)) { if (desc->action) if (irqflags & desc->action->flags & IRQF_SHARED) canrequest =1; } irq_put_desc_unlock(desc, flags); return canrequest; } int __irq_set_trigger(struct irq_desc *desc, unsigned int irq, unsigned long flags) { struct irq_chip *chip = desc->irq_data.chip; int ret, unmask = 0; if (!chip || !chip->irq_set_type) { /* * IRQF_TRIGGER_* but the PIC does not support multiple * flow-types? */ pr_debug("No set_type function for IRQ %d (%s)\n", irq, chip ? (chip->name ? : "unknown") : "unknown"); return 0; } flags &= IRQ_TYPE_SENSE_MASK; if (chip->flags & IRQCHIP_SET_TYPE_MASKED) { if (!irqd_irq_masked(&desc->irq_data)) mask_irq(desc); if (!irqd_irq_disabled(&desc->irq_data)) unmask = 1; } /* caller masked out all except trigger mode flags */ ret = chip->irq_set_type(&desc->irq_data, flags); switch (ret) { case IRQ_SET_MASK_OK: irqd_clear(&desc->irq_data, IRQD_TRIGGER_MASK); irqd_set(&desc->irq_data, flags); case IRQ_SET_MASK_OK_NOCOPY: flags = irqd_get_trigger_type(&desc->irq_data); irq_settings_set_trigger_mask(desc, flags); irqd_clear(&desc->irq_data, IRQD_LEVEL); irq_settings_clr_level(desc); if (flags & IRQ_TYPE_LEVEL_MASK) { irq_settings_set_level(desc); irqd_set(&desc->irq_data, IRQD_LEVEL); } ret = 0; break; default: pr_err("setting trigger mode %lu for irq %u failed (%pF)\n", flags, irq, chip->irq_set_type); } if (unmask) unmask_irq(desc); return ret; } /* * Default primary interrupt handler for threaded interrupts. Is * assigned as primary handler when request_threaded_irq is called * with handler == NULL. Useful for oneshot interrupts. */ static irqreturn_t irq_default_primary_handler(int irq, void *dev_id) { return IRQ_WAKE_THREAD; } /* * Primary handler for nested threaded interrupts. Should never be * called. */ static irqreturn_t irq_nested_primary_handler(int irq, void *dev_id) { WARN(1, "Primary handler called for nested irq %d\n", irq); return IRQ_NONE; } static int irq_wait_for_interrupt(struct irqaction *action) { while (!kthread_should_stop()) { set_current_state(TASK_INTERRUPTIBLE); if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags)) { __set_current_state(TASK_RUNNING); return 0; } schedule(); } return -1; } /* * Oneshot interrupts keep the irq line masked until the threaded * handler finished. unmask if the interrupt has not been disabled and * is marked MASKED. */ static void irq_finalize_oneshot(struct irq_desc *desc, struct irqaction *action, bool force) { if (!(desc->istate & IRQS_ONESHOT)) return; again: chip_bus_lock(desc); raw_spin_lock_irq(&desc->lock); /* * Implausible though it may be we need to protect us against * the following scenario: * * The thread is faster done than the hard interrupt handler * on the other CPU. If we unmask the irq line then the * interrupt can come in again and masks the line, leaves due * to IRQS_INPROGRESS and the irq line is masked forever. * * This also serializes the state of shared oneshot handlers * versus "desc->threads_onehsot |= action->thread_mask;" in * irq_wake_thread(). See the comment there which explains the * serialization. */ if (unlikely(irqd_irq_inprogress(&desc->irq_data))) { raw_spin_unlock_irq(&desc->lock); chip_bus_sync_unlock(desc); cpu_relax(); goto again; } /* * Now check again, whether the thread should run. Otherwise * we would clear the threads_oneshot bit of this thread which * was just set. */ if (!force && test_bit(IRQTF_RUNTHREAD, &action->thread_flags)) goto out_unlock; desc->threads_oneshot &= ~action->thread_mask; if (!desc->threads_oneshot && !irqd_irq_disabled(&desc->irq_data) && irqd_irq_masked(&desc->irq_data)) unmask_irq(desc); out_unlock: raw_spin_unlock_irq(&desc->lock); chip_bus_sync_unlock(desc); } #ifdef CONFIG_SMP /* * Check whether we need to chasnge the affinity of the interrupt thread. */ static void irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { cpumask_var_t mask; if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags)) return; /* * In case we are out of memory we set IRQTF_AFFINITY again and * try again next time */ if (!alloc_cpumask_var(&mask, GFP_KERNEL)) { set_bit(IRQTF_AFFINITY, &action->thread_flags); return; } raw_spin_lock_irq(&desc->lock); cpumask_copy(mask, desc->irq_data.affinity); raw_spin_unlock_irq(&desc->lock); set_cpus_allowed_ptr(current, mask); free_cpumask_var(mask); } #else static inline void irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { } #endif /* * Interrupts which are not explicitely requested as threaded * interrupts rely on the implicit bh/preempt disable of the hard irq * context. So we need to disable bh here to avoid deadlocks and other * side effects. */ static irqreturn_t irq_forced_thread_fn(struct irq_desc *desc, struct irqaction *action) { irqreturn_t ret; local_bh_disable(); ret = action->thread_fn(action->irq, action->dev_id); irq_finalize_oneshot(desc, action, false); local_bh_enable(); return ret; } /* * Interrupts explicitely requested as threaded interupts want to be * preemtible - many of them need to sleep and wait for slow busses to * complete. */ static irqreturn_t irq_thread_fn(struct irq_desc *desc, struct irqaction *action) { irqreturn_t ret; ret = action->thread_fn(action->irq, action->dev_id); irq_finalize_oneshot(desc, action, false); return ret; } /* * Interrupt handler thread */ static int irq_thread(void *data) { static const struct sched_param param = { .sched_priority = MAX_USER_RT_PRIO/2, }; struct irqaction *action = data; struct irq_desc *desc = irq_to_desc(action->irq); irqreturn_t (*handler_fn)(struct irq_desc *desc, struct irqaction *action); int wake; if (force_irqthreads & test_bit(IRQTF_FORCED_THREAD, &action->thread_flags)) handler_fn = irq_forced_thread_fn; else handler_fn = irq_thread_fn; sched_setscheduler(current, SCHED_FIFO, ¶m); current->irqaction = action; while (!irq_wait_for_interrupt(action)) { irq_thread_check_affinity(desc, action); atomic_inc(&desc->threads_active); raw_spin_lock_irq(&desc->lock); if (unlikely(irqd_irq_disabled(&desc->irq_data))) { /* * CHECKME: We might need a dedicated * IRQ_THREAD_PENDING flag here, which * retriggers the thread in check_irq_resend() * but AFAICT IRQS_PENDING should be fine as it * retriggers the interrupt itself --- tglx */ desc->istate |= IRQS_PENDING; raw_spin_unlock_irq(&desc->lock); } else { irqreturn_t action_ret; raw_spin_unlock_irq(&desc->lock); action_ret = handler_fn(desc, action); if (!noirqdebug) note_interrupt(action->irq, desc, action_ret); } wake = atomic_dec_and_test(&desc->threads_active); if (wake && waitqueue_active(&desc->wait_for_threads)) wake_up(&desc->wait_for_threads); } /* Prevent a stale desc->threads_oneshot */ irq_finalize_oneshot(desc, action, true); /* * Clear irqaction. Otherwise exit_irq_thread() would make * fuzz about an active irq thread going into nirvana. */ current->irqaction = NULL; return 0; } /* * Called from do_exit() */ void exit_irq_thread(void) { struct task_struct *tsk = current; struct irq_desc *desc; if (!tsk->irqaction) return; printk(KERN_ERR "exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n", tsk->comm ? tsk->comm : "", tsk->pid, tsk->irqaction->irq); desc = irq_to_desc(tsk->irqaction->irq); /* * Prevent a stale desc->threads_oneshot. Must be called * before setting the IRQTF_DIED flag. */ irq_finalize_oneshot(desc, tsk->irqaction, true); /* * Set the THREAD DIED flag to prevent further wakeups of the * soon to be gone threaded handler. */ set_bit(IRQTF_DIED, &tsk->irqaction->flags); } static void irq_setup_forced_threading(struct irqaction *new) { if (!force_irqthreads) return; if (new->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT)) return; new->flags |= IRQF_ONESHOT; if (!new->thread_fn) { set_bit(IRQTF_FORCED_THREAD, &new->thread_flags); new->thread_fn = new->handler; new->handler = irq_default_primary_handler; } } /* * Internal function to register an irqaction - typically used to * allocate special interrupts that are part of the architecture. */ static int __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) { struct irqaction *old, **old_ptr; const char *old_name = NULL; unsigned long flags, thread_mask = 0; int ret, nested, shared = 0; cpumask_var_t mask; if (!desc) return -EINVAL; if (desc->irq_data.chip == &no_irq_chip) return -ENOSYS; if (!try_module_get(desc->owner)) return -ENODEV; /* * Some drivers like serial.c use request_irq() heavily, * so we have to be careful not to interfere with a * running system. */ if (new->flags & IRQF_SAMPLE_RANDOM) { /* * This function might sleep, we want to call it first, * outside of the atomic block. * Yes, this might clear the entropy pool if the wrong * driver is attempted to be loaded, without actually * installing a new handler, but is this really a problem, * only the sysadmin is able to do this. */ rand_initialize_irq(irq); } /* * Check whether the interrupt nests into another interrupt * thread. */ nested = irq_settings_is_nested_thread(desc); if (nested) { if (!new->thread_fn) { ret = -EINVAL; goto out_mput; } /* * Replace the primary handler which was provided from * the driver for non nested interrupt handling by the * dummy function which warns when called. */ new->handler = irq_nested_primary_handler; } else { if (irq_settings_can_thread(desc)) irq_setup_forced_threading(new); } /* * Create a handler thread when a thread function is supplied * and the interrupt does not nest into another interrupt * thread. */ if (new->thread_fn && !nested) { struct task_struct *t; t = kthread_create(irq_thread, new, "irq/%d-%s", irq, new->name); if (IS_ERR(t)) { ret = PTR_ERR(t); goto out_mput; } /* * We keep the reference to the task struct even if * the thread dies to avoid that the interrupt code * references an already freed task_struct. */ get_task_struct(t); new->thread = t; } if (!alloc_cpumask_var(&mask, GFP_KERNEL)) { ret = -ENOMEM; goto out_thread; } /* * The following block of code has to be executed atomically */ raw_spin_lock_irqsave(&desc->lock, flags); old_ptr = &desc->action; old = *old_ptr; if (old) { /* * Can't share interrupts unless both agree to and are * the same type (level, edge, polarity). So both flag * fields must have IRQF_SHARED set and the bits which * set the trigger type must match. Also all must * agree on ONESHOT. */ if (!((old->flags & new->flags) & IRQF_SHARED) || ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK) || ((old->flags ^ new->flags) & IRQF_ONESHOT)) { old_name = old->name; goto mismatch; } /* All handlers must agree on per-cpuness */ if ((old->flags & IRQF_PERCPU) != (new->flags & IRQF_PERCPU)) goto mismatch; /* add new interrupt at end of irq queue */ do { thread_mask |= old->thread_mask; old_ptr = &old->next; old = *old_ptr; } while (old); shared = 1; } /* * Setup the thread mask for this irqaction. Unlikely to have * 32 resp 64 irqs sharing one line, but who knows. */ if (new->flags & IRQF_ONESHOT && thread_mask == ~0UL) { ret = -EBUSY; goto out_mask; } new->thread_mask = 1 << ffz(thread_mask); if (!shared) { init_waitqueue_head(&desc->wait_for_threads); /* Setup the type (level, edge polarity) if configured: */ if (new->flags & IRQF_TRIGGER_MASK) { ret = __irq_set_trigger(desc, irq, new->flags & IRQF_TRIGGER_MASK); if (ret) goto out_mask; } desc->istate &= ~(IRQS_AUTODETECT | IRQS_SPURIOUS_DISABLED | \ IRQS_ONESHOT | IRQS_WAITING); irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS); if (new->flags & IRQF_PERCPU) { irqd_set(&desc->irq_data, IRQD_PER_CPU); irq_settings_set_per_cpu(desc); } if (new->flags & IRQF_ONESHOT) desc->istate |= IRQS_ONESHOT; if (irq_settings_can_autoenable(desc)) irq_startup(desc); else /* Undo nested disables: */ desc->depth = 1; /* Exclude IRQ from balancing if requested */ if (new->flags & IRQF_NOBALANCING) { irq_settings_set_no_balancing(desc); irqd_set(&desc->irq_data, IRQD_NO_BALANCING); } /* Set default affinity mask once everything is setup */ setup_affinity(irq, desc, mask); } else if (new->flags & IRQF_TRIGGER_MASK) { unsigned int nmsk = new->flags & IRQF_TRIGGER_MASK; unsigned int omsk = irq_settings_get_trigger_mask(desc); if (nmsk != omsk) /* hope the handler works with current trigger mode */ pr_warning("IRQ %d uses trigger mode %u; requested %u\n", irq, nmsk, omsk); } new->irq = irq; *old_ptr = new; /* Reset broken irq detection when installing new handler */ desc->irq_count = 0; desc->irqs_unhandled = 0; /* * Check whether we disabled the irq via the spurious handler * before. Reenable it and give it another chance. */ if (shared && (desc->istate & IRQS_SPURIOUS_DISABLED)) { desc->istate &= ~IRQS_SPURIOUS_DISABLED; __enable_irq(desc, irq, false); } raw_spin_unlock_irqrestore(&desc->lock, flags); /* * Strictly no need to wake it up, but hung_task complains * when no hard interrupt wakes the thread up. */ if (new->thread) wake_up_process(new->thread); register_irq_proc(irq, desc); new->dir = NULL; register_handler_proc(irq, new); free_cpumask_var(mask); return 0; mismatch: #ifdef CONFIG_DEBUG_SHIRQ if (!(new->flags & IRQF_PROBE_SHARED)) { printk(KERN_ERR "IRQ handler type mismatch for IRQ %d\n", irq); if (old_name) printk(KERN_ERR "current handler: %s\n", old_name); dump_stack(); } #endif ret = -EBUSY; out_mask: raw_spin_unlock_irqrestore(&desc->lock, flags); free_cpumask_var(mask); out_thread: if (new->thread) { struct task_struct *t = new->thread; new->thread = NULL; if (likely(!test_bit(IRQTF_DIED, &new->thread_flags))) kthread_stop(t); put_task_struct(t); } out_mput: module_put(desc->owner); return ret; } /** * setup_irq - setup an interrupt * @irq: Interrupt line to setup * @act: irqaction for the interrupt * * Used to statically setup interrupts in the early boot process. */ int setup_irq(unsigned int irq, struct irqaction *act) { int retval; struct irq_desc *desc = irq_to_desc(irq); if (WARN_ON(irq_settings_is_per_cpu_devid(desc))) return -EINVAL; chip_bus_lock(desc); retval = __setup_irq(irq, desc, act); chip_bus_sync_unlock(desc); return retval; } EXPORT_SYMBOL_GPL(setup_irq); /* * Internal function to unregister an irqaction - used to free * regular and special interrupts that are part of the architecture. */ static struct irqaction *__free_irq(unsigned int irq, void *dev_id) { struct irq_desc *desc = irq_to_desc(irq); struct irqaction *action, **action_ptr; unsigned long flags; WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq); if (!desc) return NULL; raw_spin_lock_irqsave(&desc->lock, flags); /* * There can be multiple actions per IRQ descriptor, find the right * one based on the dev_id: */ action_ptr = &desc->action; for (;;) { action = *action_ptr; if (!action) { WARN(1, "Trying to free already-free IRQ %d\n", irq); raw_spin_unlock_irqrestore(&desc->lock, flags); return NULL; } if (action->dev_id == dev_id) break; action_ptr = &action->next; } /* Found it - now remove it from the list of entries: */ *action_ptr = action->next; /* Currently used only by UML, might disappear one day: */ #ifdef CONFIG_IRQ_RELEASE_METHOD if (desc->irq_data.chip->release) desc->irq_data.chip->release(irq, dev_id); #endif /* If this was the last handler, shut down the IRQ line: */ if (!desc->action) irq_shutdown(desc); #ifdef CONFIG_SMP /* make sure affinity_hint is cleaned up */ if (WARN_ON_ONCE(desc->affinity_hint)) desc->affinity_hint = NULL; #endif raw_spin_unlock_irqrestore(&desc->lock, flags); unregister_handler_proc(irq, action); /* Make sure it's not being used on another CPU: */ synchronize_irq(irq); #ifdef CONFIG_DEBUG_SHIRQ /* * It's a shared IRQ -- the driver ought to be prepared for an IRQ * event to happen even now it's being freed, so let's make sure that * is so by doing an extra call to the handler .... * * ( We do this after actually deregistering it, to make sure that a * 'real' IRQ doesn't run in * parallel with our fake. ) */ if (action->flags & IRQF_SHARED) { local_irq_save(flags); action->handler(irq, dev_id); local_irq_restore(flags); } #endif if (action->thread) { if (!test_bit(IRQTF_DIED, &action->thread_flags)) kthread_stop(action->thread); put_task_struct(action->thread); } module_put(desc->owner); return action; } /** * remove_irq - free an interrupt * @irq: Interrupt line to free * @act: irqaction for the interrupt * * Used to remove interrupts statically setup by the early boot process. */ void remove_irq(unsigned int irq, struct irqaction *act) { struct irq_desc *desc = irq_to_desc(irq); if (desc && !WARN_ON(irq_settings_is_per_cpu_devid(desc))) __free_irq(irq, act->dev_id); } EXPORT_SYMBOL_GPL(remove_irq); /** * free_irq - free an interrupt allocated with request_irq * @irq: Interrupt line to free * @dev_id: Device identity to free * * Remove an interrupt handler. The handler is removed and if the * interrupt line is no longer in use by any driver it is disabled. * On a shared IRQ the caller must ensure the interrupt is disabled * on the card it drives before calling this function. The function * does not return until any executing interrupts for this IRQ * have completed. * * This function must not be called from interrupt context. */ void free_irq(unsigned int irq, void *dev_id) { struct irq_desc *desc = irq_to_desc(irq); if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc))) return; #ifdef CONFIG_SMP if (WARN_ON(desc->affinity_notify)) desc->affinity_notify = NULL; #endif chip_bus_lock(desc); kfree(__free_irq(irq, dev_id)); chip_bus_sync_unlock(desc); } EXPORT_SYMBOL(free_irq); /** * request_threaded_irq - allocate an interrupt line * @irq: Interrupt line to allocate * @handler: Function to be called when the IRQ occurs. * Primary handler for threaded interrupts * If NULL and thread_fn != NULL the default * primary handler is installed * @thread_fn: Function called from the irq handler thread * If NULL, no irq thread is created * @irqflags: Interrupt type flags * @devname: An ascii name for the claiming device * @dev_id: A cookie passed back to the handler function * * This call allocates interrupt resources and enables the * interrupt line and IRQ handling. From the point this * call is made your handler function may be invoked. Since * your handler function must clear any interrupt the board * raises, you must take care both to initialise your hardware * and to set up the interrupt handler in the right order. * * If you want to set up a threaded irq handler for your device * then you need to supply @handler and @thread_fn. @handler ist * still called in hard interrupt context and has to check * whether the interrupt originates from the device. If yes it * needs to disable the interrupt on the device and return * IRQ_WAKE_THREAD which will wake up the handler thread and run * @thread_fn. This split handler design is necessary to support * shared interrupts. * * Dev_id must be globally unique. Normally the address of the * device data structure is used as the cookie. Since the handler * receives this value it makes sense to use it. * * If your interrupt is shared you must pass a non NULL dev_id * as this is required when freeing the interrupt. * * Flags: * * IRQF_SHARED Interrupt is shared * IRQF_SAMPLE_RANDOM The interrupt can be used for entropy * IRQF_TRIGGER_* Specify active edge(s) or level * */ int request_threaded_irq(unsigned int irq, irq_handler_t handler, irq_handler_t thread_fn, unsigned long irqflags, const char *devname, void *dev_id) { struct irqaction *action; struct irq_desc *desc; int retval; /* * Sanity-check: shared interrupts must pass in a real dev-ID, * otherwise we'll have trouble later trying to figure out * which interrupt is which (messes up the interrupt freeing * logic etc). */ if ((irqflags & IRQF_SHARED) && !dev_id) return -EINVAL; desc = irq_to_desc(irq); if (!desc) return -EINVAL; if (!irq_settings_can_request(desc) || WARN_ON(irq_settings_is_per_cpu_devid(desc))) return -EINVAL; if (!handler) { if (!thread_fn) return -EINVAL; handler = irq_default_primary_handler; } action = kzalloc(sizeof(struct irqaction), GFP_KERNEL); if (!action) return -ENOMEM; action->handler = handler; action->thread_fn = thread_fn; action->flags = irqflags; action->name = devname; action->dev_id = dev_id; chip_bus_lock(desc); retval = __setup_irq(irq, desc, action); chip_bus_sync_unlock(desc); if (retval) kfree(action); #ifdef CONFIG_DEBUG_SHIRQ_FIXME if (!retval && (irqflags & IRQF_SHARED)) { /* * It's a shared IRQ -- the driver ought to be prepared for it * to happen immediately, so let's make sure.... * We disable the irq to make sure that a 'real' IRQ doesn't * run in parallel with our fake. */ unsigned long flags; disable_irq(irq); local_irq_save(flags); handler(irq, dev_id); local_irq_restore(flags); enable_irq(irq); } #endif return retval; } EXPORT_SYMBOL(request_threaded_irq); /** * request_any_context_irq - allocate an interrupt line * @irq: Interrupt line to allocate * @handler: Function to be called when the IRQ occurs. * Threaded handler for threaded interrupts. * @flags: Interrupt type flags * @name: An ascii name for the claiming device * @dev_id: A cookie passed back to the handler function * * This call allocates interrupt resources and enables the * interrupt line and IRQ handling. It selects either a * hardirq or threaded handling method depending on the * context. * * On failure, it returns a negative value. On success, * it returns either IRQC_IS_HARDIRQ or IRQC_IS_NESTED. */ int request_any_context_irq(unsigned int irq, irq_handler_t handler, unsigned long flags, const char *name, void *dev_id) { struct irq_desc *desc = irq_to_desc(irq); int ret; if (!desc) return -EINVAL; if (irq_settings_is_nested_thread(desc)) { ret = request_threaded_irq(irq, NULL, handler, flags, name, dev_id); return !ret ? IRQC_IS_NESTED : ret; } ret = request_irq(irq, handler, flags, name, dev_id); return !ret ? IRQC_IS_HARDIRQ : ret; } EXPORT_SYMBOL_GPL(request_any_context_irq); void enable_percpu_irq(unsigned int irq, unsigned int type) { unsigned int cpu = smp_processor_id(); unsigned long flags; struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU); if (!desc) return; type &= IRQ_TYPE_SENSE_MASK; if (type != IRQ_TYPE_NONE) { int ret; ret = __irq_set_trigger(desc, irq, type); if (ret) { WARN(1, "failed to set type for IRQ%d\n, irq"); goto out; } } irq_percpu_enable(desc, cpu); out: irq_put_desc_unlock(desc, flags); } void disable_percpu_irq(unsigned int irq) { unsigned int cpu = smp_processor_id(); unsigned long flags; struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU); if (!desc) return; irq_percpu_disable(desc, cpu); irq_put_desc_unlock(desc, flags); } /* * Internal function to unregister a percpu irqaction. */ static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_id) { struct irq_desc *desc = irq_to_desc(irq); struct irqaction *action; unsigned long flags; WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq); if (!desc) return NULL; raw_spin_lock_irqsave(&desc->lock, flags); action = desc->action; if (!action || action->percpu_dev_id != dev_id) { WARN(1, "Trying to free already-free IRQ %d\n", irq); goto bad; } if (!cpumask_empty(desc->percpu_enabled)) { WARN(1, "percpu IRQ %d still enabled on CPU%d!\n", irq, cpumask_first(desc->percpu_enabled)); goto bad; } /* Found it - now remove it from the list of entries: */ desc->action = NULL; raw_spin_unlock_irqrestore(&desc->lock, flags); unregister_handler_proc(irq, action); module_put(desc->owner); return action; bad: raw_spin_unlock_irqrestore(&desc->lock, flags); return NULL; } /** * remove_percpu_irq - free a per-cpu interrupt * @irq: Interrupt line to free * @act: irqaction for the interrupt * * Used to remove interrupts statically setup by the early boot process. */ void remove_percpu_irq(unsigned int irq, struct irqaction *act) { struct irq_desc *desc = irq_to_desc(irq); if (desc && irq_settings_is_per_cpu_devid(desc)) __free_percpu_irq(irq, act->percpu_dev_id); } /** * free_percpu_irq - free an interrupt allocated with request_percpu_irq * @irq: Interrupt line to free * @dev_id: Device identity to free * * Remove a percpu interrupt handler. The handler is removed, but * the interrupt line is not disabled. This must be done on each * CPU before calling this function. The function does not return * until any executing interrupts for this IRQ have completed. * * This function must not be called from interrupt context. */ void free_percpu_irq(unsigned int irq, void __percpu *dev_id) { struct irq_desc *desc = irq_to_desc(irq); if (!desc || !irq_settings_is_per_cpu_devid(desc)) return; chip_bus_lock(desc); kfree(__free_percpu_irq(irq, dev_id)); chip_bus_sync_unlock(desc); } /** * setup_percpu_irq - setup a per-cpu interrupt * @irq: Interrupt line to setup * @act: irqaction for the interrupt * * Used to statically setup per-cpu interrupts in the early boot process. */ int setup_percpu_irq(unsigned int irq, struct irqaction *act) { struct irq_desc *desc = irq_to_desc(irq); int retval; if (!desc || !irq_settings_is_per_cpu_devid(desc)) return -EINVAL; chip_bus_lock(desc); retval = __setup_irq(irq, desc, act); chip_bus_sync_unlock(desc); return retval; } /** * request_percpu_irq - allocate a percpu interrupt line * @irq: Interrupt line to allocate * @handler: Function to be called when the IRQ occurs. * @devname: An ascii name for the claiming device * @dev_id: A percpu cookie passed back to the handler function * * This call allocates interrupt resources, but doesn't * automatically enable the interrupt. It has to be done on each * CPU using enable_percpu_irq(). * * Dev_id must be globally unique. It is a per-cpu variable, and * the handler gets called with the interrupted CPU's instance of * that variable. */ int request_percpu_irq(unsigned int irq, irq_handler_t handler, const char *devname, void __percpu *dev_id) { struct irqaction *action; struct irq_desc *desc; int retval; if (!dev_id) return -EINVAL; desc = irq_to_desc(irq); if (!desc || !irq_settings_can_request(desc) || !irq_settings_is_per_cpu_devid(desc)) return -EINVAL; action = kzalloc(sizeof(struct irqaction), GFP_KERNEL); if (!action) return -ENOMEM; action->handler = handler; action->flags = IRQF_PERCPU; action->name = devname; action->percpu_dev_id = dev_id; chip_bus_lock(desc); retval = __setup_irq(irq, desc, action); chip_bus_sync_unlock(desc); if (retval) kfree(action); return retval; }