diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /kernel/irq/manage.c |
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'kernel/irq/manage.c')
-rw-r--r-- | kernel/irq/manage.c | 349 |
1 files changed, 349 insertions, 0 deletions
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c new file mode 100644 index 000000000000..5202e4c4a5b6 --- /dev/null +++ b/kernel/irq/manage.c @@ -0,0 +1,349 @@ +/* + * linux/kernel/irq/manage.c + * + * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar + * + * 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 "internals.h" + +#ifdef CONFIG_SMP + +cpumask_t irq_affinity[NR_IRQS] = { [0 ... NR_IRQS-1] = CPU_MASK_ALL }; + +/** + * synchronize_irq - wait for pending IRQ handlers (on other CPUs) + * + * 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_desc + irq; + + while (desc->status & IRQ_INPROGRESS) + cpu_relax(); +} + +EXPORT_SYMBOL(synchronize_irq); + +#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) +{ + irq_desc_t *desc = irq_desc + irq; + unsigned long flags; + + spin_lock_irqsave(&desc->lock, flags); + if (!desc->depth++) { + desc->status |= IRQ_DISABLED; + desc->handler->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) +{ + irq_desc_t *desc = irq_desc + irq; + + disable_irq_nosync(irq); + if (desc->action) + synchronize_irq(irq); +} + +EXPORT_SYMBOL(disable_irq); + +/** + * 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) +{ + irq_desc_t *desc = irq_desc + irq; + unsigned long flags; + + spin_lock_irqsave(&desc->lock, flags); + switch (desc->depth) { + case 0: + WARN_ON(1); + break; + case 1: { + unsigned int status = desc->status & ~IRQ_DISABLED; + + desc->status = status; + if ((status & (IRQ_PENDING | IRQ_REPLAY)) == IRQ_PENDING) { + desc->status = status | IRQ_REPLAY; + hw_resend_irq(desc->handler,irq); + } + desc->handler->enable(irq); + /* fall-through */ + } + default: + desc->depth--; + } + spin_unlock_irqrestore(&desc->lock, flags); +} + +EXPORT_SYMBOL(enable_irq); + +/* + * 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 irqaction *action; + + if (irq >= NR_IRQS) + return 0; + + action = irq_desc[irq].action; + if (action) + if (irqflags & action->flags & SA_SHIRQ) + action = NULL; + + return !action; +} + +/* + * Internal function to register an irqaction - typically used to + * allocate special interrupts that are part of the architecture. + */ +int setup_irq(unsigned int irq, struct irqaction * new) +{ + struct irq_desc *desc = irq_desc + irq; + struct irqaction *old, **p; + unsigned long flags; + int shared = 0; + + if (desc->handler == &no_irq_type) + 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 & SA_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; + if ((old = *p) != NULL) { + /* Can't share interrupts unless both agree to */ + if (!(old->flags & new->flags & SA_SHIRQ)) { + spin_unlock_irqrestore(&desc->lock,flags); + return -EBUSY; + } + + /* add new interrupt at end of irq queue */ + do { + p = &old->next; + old = *p; + } while (old); + shared = 1; + } + + *p = new; + + if (!shared) { + desc->depth = 0; + desc->status &= ~(IRQ_DISABLED | IRQ_AUTODETECT | + IRQ_WAITING | IRQ_INPROGRESS); + if (desc->handler->startup) + desc->handler->startup(irq); + else + desc->handler->enable(irq); + } + spin_unlock_irqrestore(&desc->lock,flags); + + new->irq = irq; + register_irq_proc(irq); + new->dir = NULL; + register_handler_proc(irq, new); + + return 0; +} + +/** + * 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; + struct irqaction **p; + unsigned long flags; + + if (irq >= NR_IRQS) + return; + + desc = irq_desc + irq; + 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; + if (!desc->action) { + desc->status |= IRQ_DISABLED; + if (desc->handler->shutdown) + desc->handler->shutdown(irq); + else + desc->handler->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); + kfree(action); + return; + } + printk(KERN_ERR "Trying to free free IRQ%d\n",irq); + 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: + * + * SA_SHIRQ Interrupt is shared + * SA_INTERRUPT Disable local interrupts while processing + * SA_SAMPLE_RANDOM The interrupt can be used for entropy + * + */ +int request_irq(unsigned int irq, + irqreturn_t (*handler)(int, void *, struct pt_regs *), + unsigned long irqflags, const char * devname, void *dev_id) +{ + struct irqaction * action; + 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 & SA_SHIRQ) && !dev_id) + return -EINVAL; + if (irq >= NR_IRQS) + return -EINVAL; + if (!handler) + return -EINVAL; + + action = kmalloc(sizeof(struct irqaction), GFP_ATOMIC); + 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, action); + if (retval) + kfree(action); + + return retval; +} + +EXPORT_SYMBOL(request_irq); + |