/* * 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" /** * 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); unsigned int status; 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 (desc->status & IRQ_INPROGRESS) cpu_relax(); /* Ok, that indicated we're done: double-check carefully. */ raw_spin_lock_irqsave(&desc->lock, flags); status = desc->status; raw_spin_unlock_irqrestore(&desc->lock, flags); /* Oops, that failed? */ } while (status & IRQ_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 (CHECK_IRQ_PER_CPU(desc->status) || !desc->chip || !desc->chip->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; } } /** * irq_set_affinity - Set the irq affinity of a given irq * @irq: Interrupt to set affinity * @cpumask: cpumask * */ int irq_set_affinity(unsigned int irq, const struct cpumask *cpumask) { struct irq_desc *desc = irq_to_desc(irq); unsigned long flags; if (!desc->chip->set_affinity) return -EINVAL; raw_spin_lock_irqsave(&desc->lock, flags); #ifdef CONFIG_GENERIC_PENDING_IRQ if (desc->status & IRQ_MOVE_PCNTXT) { if (!desc->chip->set_affinity(irq, cpumask)) { cpumask_copy(desc->affinity, cpumask); irq_set_thread_affinity(desc); } } else { desc->status |= IRQ_MOVE_PENDING; cpumask_copy(desc->pending_mask, cpumask); } #else if (!desc->chip->set_affinity(irq, cpumask)) { cpumask_copy(desc->affinity, cpumask); irq_set_thread_affinity(desc); } #endif desc->status |= IRQ_AFFINITY_SET; raw_spin_unlock_irqrestore(&desc->lock, flags); return 0; } #ifndef CONFIG_AUTO_IRQ_AFFINITY /* * Generic version of the affinity autoselector. */ static int setup_affinity(unsigned int irq, struct irq_desc *desc) { if (!irq_can_set_affinity(irq)) return 0; /* * Preserve an userspace affinity setup, but make sure that * one of the targets is online. */ if (desc->status & (IRQ_AFFINITY_SET | IRQ_NO_BALANCING)) { if (cpumask_any_and(desc->affinity, cpu_online_mask) < nr_cpu_ids) goto set_affinity; else desc->status &= ~IRQ_AFFINITY_SET; } cpumask_and(desc->affinity, cpu_online_mask, irq_default_affinity); set_affinity: desc->chip->set_affinity(irq, desc->affinity); return 0; } #else static inline int setup_affinity(unsigned int irq, struct irq_desc *d) { return irq_select_affinity(irq); } #endif /* * Called when affinity is set via /proc/irq */ int irq_select_affinity_usr(unsigned int irq) { 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); if (!ret) irq_set_thread_affinity(desc); raw_spin_unlock_irqrestore(&desc->lock, flags); return ret; } #else static inline int setup_affinity(unsigned int irq, struct irq_desc *desc) { return 0; } #endif void __disable_irq(struct irq_desc *desc, unsigned int irq, bool suspend) { if (suspend) { if (!desc->action || (desc->action->flags & IRQF_TIMER)) return; desc->status |= IRQ_SUSPENDED; } if (!desc->depth++) { desc->status |= IRQ_DISABLED; desc->chip->disable(irq); } } /** * 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) { struct irq_desc *desc = irq_to_desc(irq); unsigned long flags; if (!desc) return; chip_bus_lock(irq, desc); raw_spin_lock_irqsave(&desc->lock, flags); __disable_irq(desc, irq, false); raw_spin_unlock_irqrestore(&desc->lock, flags); chip_bus_sync_unlock(irq, desc); } 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) { struct irq_desc *desc = irq_to_desc(irq); if (!desc) return; disable_irq_nosync(irq); if (desc->action) synchronize_irq(irq); } EXPORT_SYMBOL(disable_irq); void __enable_irq(struct irq_desc *desc, unsigned int irq, bool resume) { if (resume) desc->status &= ~IRQ_SUSPENDED; switch (desc->depth) { case 0: err_out: WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq); break; case 1: { unsigned int status = desc->status & ~IRQ_DISABLED; if (desc->status & IRQ_SUSPENDED) goto err_out; /* Prevent probing on this irq: */ desc->status = status | IRQ_NOPROBE; if (!desc->forced_threads_active) 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->chip->bus_lock and desc->chip->bus_sync_unlock are NULL ! */ void enable_irq(unsigned int irq) { struct irq_desc *desc = irq_to_desc(irq); unsigned long flags; if (!desc) return; chip_bus_lock(irq, desc); raw_spin_lock_irqsave(&desc->lock, flags); __enable_irq(desc, irq, false); raw_spin_unlock_irqrestore(&desc->lock, flags); chip_bus_sync_unlock(irq, desc); } 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 (desc->chip->set_wake) ret = desc->chip->set_wake(irq, on); return ret; } /** * 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 set_irq_wake(unsigned int irq, unsigned int on) { struct irq_desc *desc = irq_to_desc(irq); unsigned long flags; int ret = 0; /* wakeup-capable irqs can be shared between drivers that * don't need to have the same sleep mode behaviors. */ raw_spin_lock_irqsave(&desc->lock, flags); if (on) { if (desc->wake_depth++ == 0) { ret = set_irq_wake_real(irq, on); if (ret) desc->wake_depth = 0; else desc->status |= IRQ_WAKEUP; } } 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 desc->status &= ~IRQ_WAKEUP; } } raw_spin_unlock_irqrestore(&desc->lock, flags); return ret; } EXPORT_SYMBOL(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) { struct irq_desc *desc = irq_to_desc(irq); struct irqaction *action; if (!desc) return 0; if (desc->status & IRQ_NOREQUEST) return 0; action = desc->action; if (action) if (irqflags & action->flags & IRQF_SHARED) action = NULL; return !action; } void compat_irq_chip_set_default_handler(struct irq_desc *desc) { /* * If the architecture still has not overriden * the flow handler then zap the default. This * should catch incorrect flow-type setting. */ if (desc->handle_irq == &handle_bad_irq) desc->handle_irq = NULL; } int __irq_set_trigger(struct irq_desc *desc, unsigned int irq, unsigned long flags) { int ret; struct irq_chip *chip = desc->chip; if (!chip || !chip->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; } /* caller masked out all except trigger mode flags */ ret = chip->set_type(irq, flags); if (ret) pr_err("setting trigger mode %d for irq %u failed (%pF)\n", (int)flags, irq, chip->set_type); else { if (flags & (IRQ_TYPE_LEVEL_LOW | IRQ_TYPE_LEVEL_HIGH)) flags |= IRQ_LEVEL; /* note that IRQF_TRIGGER_MASK == IRQ_TYPE_SENSE_MASK */ desc->status &= ~(IRQ_LEVEL | IRQ_TYPE_SENSE_MASK); desc->status |= flags; } 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; } #ifdef CONFIG_PREEMPT_HARDIRQS /* * If the caller does not request irq threading then the handler * becomes the thread function and we use the above handler as the * primary hardirq context handler. */ static void preempt_hardirq_setup(struct irqaction *new) { if (new->thread_fn || (new->flags & (IRQF_NODELAY | IRQF_PERCPU))) return; new->flags |= IRQF_ONESHOT; new->thread_fn = new->handler; new->handler = irq_default_primary_handler; } #else static inline void preempt_hardirq_setup(struct irqaction *new) { } #endif /* * forced threaded interrupts need to unmask the interrupt line */ static int preempt_hardirq_thread_done(struct irq_desc *desc, struct irqaction *action) { unsigned long masked; if (!(desc->status & IRQ_ONESHOT)) return 0; again: raw_spin_lock_irq(&desc->lock); /* * Be careful. The hardirq handler might be running on the * other CPU. */ if (desc->status & IRQ_INPROGRESS) { raw_spin_unlock_irq(&desc->lock); cpu_relax(); goto again; } /* * Now check again, whether the thread should run. Otherwise * we would clear the forced_threads_active bit which was just * set. */ if (test_bit(IRQTF_RUNTHREAD, &action->thread_flags)) { raw_spin_unlock_irq(&desc->lock); return 1; } masked = desc->forced_threads_active; desc->forced_threads_active &= ~action->thread_mask; /* * Unmask the interrupt line when this is the last active * thread and the interrupt is not disabled. */ if (masked && !desc->forced_threads_active && !(desc->status & IRQ_DISABLED)) { if (desc->chip->unmask) desc->chip->unmask(action->irq); /* * Do we need to call check_irq_resend() here ? * No. check_irq_resend needs only to be checked when * we go from IRQ_DISABLED to IRQ_ENABLED state. */ } raw_spin_unlock_irq(&desc->lock); return 0; } static inline void preempt_hardirq_cleanup(struct irq_desc *desc, struct irqaction *action) { clear_bit(IRQTF_RUNTHREAD, &action->thread_flags); preempt_hardirq_thread_done(desc, action); } static int irq_wait_for_interrupt(struct irq_desc *desc, 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(unsigned int irq, struct irq_desc *desc, struct irqaction *action) { again: chip_bus_lock(irq, desc); #ifndef CONFIG_PREEMPT_RT 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 IRQ_INPROGRESS and the irq line is masked forever. */ if (unlikely(desc->status & IRQ_INPROGRESS)) { raw_spin_unlock_irq(&desc->lock); chip_bus_sync_unlock(irq, desc); cpu_relax(); goto again; } if (!(desc->status & IRQ_DISABLED) && (desc->status & IRQ_MASKED)) { desc->status &= ~IRQ_MASKED; desc->chip->unmask(irq); } raw_spin_unlock_irq(&desc->lock); #else preempt_hardirq_thread_done(desc, action); #endif chip_bus_sync_unlock(irq, desc); } #ifdef CONFIG_SMP /* * Check whether we need to change 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->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 /* * Interrupt handler thread */ static int irq_thread(void *data) { struct sched_param param = { .sched_priority = MAX_USER_RT_PRIO/2, }; struct irqaction *action = data; struct irq_desc *desc = irq_to_desc(action->irq); int wake; sched_setscheduler(current, SCHED_FIFO, ¶m); current->extra_flags |= PFE_HARDIRQ; current->irqaction = action; while (!irq_wait_for_interrupt(desc, action)) { irq_thread_check_affinity(desc, action); atomic_inc(&desc->threads_active); raw_spin_lock_irq(&desc->lock); if (unlikely(desc->status & IRQ_DISABLED)) { /* * CHECKME: We might need a dedicated * IRQ_THREAD_PENDING flag here, which * retriggers the thread in check_irq_resend() * but AFAICT IRQ_PENDING should be fine as it * retriggers the interrupt itself --- tglx */ desc->status |= IRQ_PENDING; raw_spin_unlock_irq(&desc->lock); } else { raw_spin_unlock_irq(&desc->lock); action->thread_fn(action->irq, action->dev_id); if (desc->status & IRQ_ONESHOT) irq_finalize_oneshot(action->irq, desc, action); } wake = atomic_dec_and_test(&desc->threads_active); if (wake && waitqueue_active(&desc->wait_for_threads)) wake_up(&desc->wait_for_threads); } preempt_hardirq_cleanup(desc, action); /* * 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; 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); /* * Set the THREAD DIED flag to prevent further wakeups of the * soon to be gone threaded handler. */ set_bit(IRQTF_DIED, &tsk->irqaction->flags); } /* * 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 nested, shared = 0; int ret; if (!desc) return -EINVAL; if (desc->chip == &no_irq_chip) return -ENOSYS; /* * 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); } /* Preempt-RT setup for forced threading */ preempt_hardirq_setup(new); /* * Check whether the interrupt nests into another interrupt * thread. */ nested = desc->status & IRQ_NESTED_THREAD; if (nested) { if (!new->thread_fn) return -EINVAL; /* * 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; } /* * 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)) return PTR_ERR(t); /* * 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; } /* * 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. */ if (!((old->flags & new->flags) & IRQF_SHARED) || ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK)) { old_name = old->name; goto mismatch; } #if defined(CONFIG_IRQ_PER_CPU) /* All handlers must agree on per-cpuness */ if ((old->flags & IRQF_PERCPU) != (new->flags & IRQF_PERCPU)) goto mismatch; #endif /* 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. No risk that ffz * will fail. If we have 32 resp. 64 devices sharing one irq * then ..... */ new->thread_mask = 1 << ffz(thread_mask); if (!shared) { irq_chip_set_defaults(desc->chip); 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_thread; } else compat_irq_chip_set_default_handler(desc); #if defined(CONFIG_IRQ_PER_CPU) if (new->flags & IRQF_PERCPU) desc->status |= IRQ_PER_CPU; #endif desc->status &= ~(IRQ_AUTODETECT | IRQ_WAITING | IRQ_ONESHOT | IRQ_INPROGRESS | IRQ_SPURIOUS_DISABLED); if (new->flags & IRQF_ONESHOT) desc->status |= IRQ_ONESHOT; /* * Force MSI interrupts to run with interrupts * disabled. The multi vector cards can cause stack * overflows due to nested interrupts when enough of * them are directed to a core and fire at the same * time. */ if (desc->msi_desc) new->flags |= IRQF_DISABLED; if (!(desc->status & IRQ_NOAUTOEN)) { desc->depth = 0; desc->status &= ~IRQ_DISABLED; desc->chip->startup(irq); } else /* Undo nested disables: */ desc->depth = 1; /* Exclude IRQ from balancing if requested */ if (new->flags & IRQF_NOBALANCING) desc->status |= IRQ_NO_BALANCING; /* Set default affinity mask once everything is setup */ setup_affinity(irq, desc); } else if ((new->flags & IRQF_TRIGGER_MASK) && (new->flags & IRQF_TRIGGER_MASK) != (desc->status & IRQ_TYPE_SENSE_MASK)) { /* hope the handler works with the actual trigger mode... */ pr_warning("IRQ %d uses trigger mode %d; requested %d\n", irq, (int)(desc->status & IRQ_TYPE_SENSE_MASK), (int)(new->flags & IRQF_TRIGGER_MASK)); } 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->status & IRQ_SPURIOUS_DISABLED)) { desc->status &= ~IRQ_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); 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_thread: raw_spin_unlock_irqrestore(&desc->lock, flags); 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); } 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) { struct irq_desc *desc = irq_to_desc(irq); return __setup_irq(irq, desc, act); } 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->chip->release) desc->chip->release(irq, dev_id); #endif /* If this was the last handler, shut down the IRQ line: */ if (!desc->action) { desc->status |= IRQ_DISABLED; if (desc->chip->shutdown) desc->chip->shutdown(irq); else desc->chip->disable(irq); } 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); } 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) { __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) return; chip_bus_lock(irq, desc); kfree(__free_irq(irq, dev_id)); chip_bus_sync_unlock(irq, 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_DISABLED Disable local interrupts while processing * 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; /* * handle_IRQ_event() always ignores IRQF_DISABLED except for * the _first_ irqaction (sigh). That can cause oopsing, but * the behavior is classified as "will not fix" so we need to * start nudging drivers away from using that idiom. */ if ((irqflags & (IRQF_SHARED|IRQF_DISABLED)) == (IRQF_SHARED|IRQF_DISABLED)) { pr_warning( "IRQ %d/%s: IRQF_DISABLED is not guaranteed on shared IRQs\n", irq, devname); } #ifdef CONFIG_LOCKDEP /* * Lockdep wants atomic interrupt handlers: */ irqflags |= IRQF_DISABLED; #endif /* * 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 (desc->status & IRQ_NOREQUEST) 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(irq, desc); retval = __setup_irq(irq, desc, action); chip_bus_sync_unlock(irq, desc); if (retval) kfree(action); #ifdef CONFIG_DEBUG_SHIRQ 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);