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linux
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/* * 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 <linux/irq.h> #include <linux/module.h> #include <linux/random.h> #include <linux/interrupt.h> #include <linux/slab.h> #include "internals.h" #ifdef CONFIG_SMP cpumask_var_t irq_default_affinity; static int init_irq_default_affinity(void) { alloc_cpumask_var(&irq_default_affinity, GFP_KERNEL); cpumask_setall(irq_default_affinity); return 0; } core_initcall(init_irq_default_affinity); /** * 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. */ spin_lock_irqsave(&desc->lock, flags); status = desc->status; spin_unlock_irqrestore(&desc->lock, flags); /* Oops, that failed? */ } while (status & IRQ_INPROGRESS); } EXPORT_SYMBOL(synchronize_irq); /** * 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_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; spin_lock_irqsave(&desc->lock, flags); #ifdef CONFIG_GENERIC_PENDING_IRQ if (desc->status & IRQ_MOVE_PCNTXT || desc->status & IRQ_DISABLED) { cpumask_copy(&desc->affinity, cpumask); desc->chip->set_affinity(irq, cpumask); } else { desc->status |= IRQ_MOVE_PENDING; cpumask_copy(&desc->pending_mask, cpumask); } #else cpumask_copy(&desc->affinity, cpumask); desc->chip->set_affinity(irq, cpumask); #endif desc->status |= IRQ_AFFINITY_SET; spin_unlock_irqrestore(&desc->lock, flags); return 0; } #ifndef CONFIG_AUTO_IRQ_AFFINITY /* * Generic version of the affinity autoselector. */ int do_irq_select_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 do_irq_select_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; spin_lock_irqsave(&desc->lock, flags); ret = do_irq_select_affinity(irq, desc); spin_unlock_irqrestore(&desc->lock, flags); return ret; } #else static inline int do_irq_select_affinity(int irq, struct irq_desc *desc) { return 0; } #endif /** * 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; spin_lock_irqsave(&desc->lock, flags); if (!desc->depth++) { desc->status |= IRQ_DISABLED; desc->chip->disable(irq); } spin_unlock_irqrestore(&desc->lock, flags); } 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); static void __enable_irq(struct irq_desc *desc, unsigned int irq) { switch (desc->depth) { case 0: WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq); break; case 1: { unsigned int status = desc->status & ~IRQ_DISABLED; /* Prevent probing on this irq: */ desc->status = status | IRQ_NOPROBE; 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. */ void enable_irq(unsigned int irq) { struct irq_desc *desc = irq_to_desc(irq); unsigned long flags; if (!desc) return; spin_lock_irqsave(&desc->lock, flags); __enable_irq(desc, irq); spin_unlock_irqrestore(&desc->lock, 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 (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. */ 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; } } 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; } /* * 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, **p; const char *old_name = NULL; unsigned long flags; int 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); } /* * The following block of code has to be executed atomically */ spin_lock_irqsave(&desc->lock, flags); p = &desc->action; old = *p; 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 { p = &old->next; old = *p; } while (old); shared = 1; } if (!shared) { irq_chip_set_defaults(desc->chip); /* 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) { spin_unlock_irqrestore(&desc->lock, flags); return ret; } } 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_INPROGRESS | IRQ_SPURIOUS_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 */ do_irq_select_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)); } *p = 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); } spin_unlock_irqrestore(&desc->lock, flags); new->irq = irq; 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 spin_unlock_irqrestore(&desc->lock, flags); return -EBUSY; } /** * 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); } /** * free_irq - free an interrupt * @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); struct irqaction **p; unsigned long flags; WARN_ON(in_interrupt()); if (!desc) return; spin_lock_irqsave(&desc->lock, flags); p = &desc->action; for (;;) { struct irqaction *action = *p; if (action) { struct irqaction **pp = p; p = &action->next; if (action->dev_id != dev_id) continue; /* Found it - now remove it from the list of entries */ *pp = 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 (!desc->action) { desc->status |= IRQ_DISABLED; if (desc->chip->shutdown) desc->chip->shutdown(irq); else desc->chip->disable(irq); } 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 it to happen even now it's * being freed, so let's make sure.... 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 kfree(action); return; } printk(KERN_ERR "Trying to free already-free IRQ %d\n", irq); #ifdef CONFIG_DEBUG_SHIRQ dump_stack(); #endif spin_unlock_irqrestore(&desc->lock, flags); return; } } EXPORT_SYMBOL(free_irq); /** * request_irq - allocate an interrupt line * @irq: Interrupt line to allocate * @handler: Function to be called when the IRQ occurs * @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. * * 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_irq(unsigned int irq, irq_handler_t handler, 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) return -EINVAL; action = kmalloc(sizeof(struct irqaction), GFP_KERNEL); if (!action) return -ENOMEM; action->handler = handler; action->flags = irqflags; cpus_clear(action->mask); action->name = devname; action->next = NULL; action->dev_id = dev_id; retval = __setup_irq(irq, desc, action); if (retval) kfree(action); #ifdef CONFIG_DEBUG_SHIRQ if (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_irq);
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