irq.c

来自「优龙2410linux2.6.8内核源代码」· C语言 代码 · 共 821 行 · 第 1/2 页

	if (!handler)
		return -EINVAL;

	action = (struct irqaction *)
			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, action);
	if (retval)
		kfree(action);
	return retval;
}

EXPORT_SYMBOL(request_irq);

int um_request_irq(unsigned int irq, int fd, int type,
		   void (*handler)(int, void *, struct pt_regs *),
		   unsigned long irqflags, const char * devname,
		   void *dev_id)
{
	int retval;

	retval = request_irq(irq, handler, irqflags, devname, dev_id);
	if(retval) return(retval);
	return(activate_fd(irq, fd, type, dev_id));
}

/* this was setup_x86_irq but it seems pretty generic */
int setup_irq(unsigned int irq, struct irqaction * new)
{
	int shared = 0;
	unsigned long flags;
	struct irqaction *old, **p;
	irq_desc_t *desc = irq_desc + irq;

	/*
	 * 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;
		desc->handler->startup(irq);
	}
	spin_unlock_irqrestore(&desc->lock,flags);

	register_irq_proc(irq);
	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 may be called from interrupt context. 
 *
 *	Bugs: Attempting to free an irq in a handler for the same irq hangs
 *	      the machine.
 */
 
void free_irq(unsigned int irq, void *dev_id)
{
	irq_desc_t *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;
				desc->handler->shutdown(irq);
			}
			free_irq_by_irq_and_dev(irq, dev_id);
			spin_unlock_irqrestore(&desc->lock,flags);

			/* Wait to 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);

/* These are initialized by sysctl_init, which is called from init/main.c */
static struct proc_dir_entry * root_irq_dir;
static struct proc_dir_entry * irq_dir [NR_IRQS];
static struct proc_dir_entry * smp_affinity_entry [NR_IRQS];

/* These are read and written as longs, so a read won't see a partial write
 * even during a race.
 */
static cpumask_t irq_affinity [NR_IRQS] = { [0 ... NR_IRQS-1] = CPU_MASK_ALL };

static int irq_affinity_read_proc (char *page, char **start, off_t off,
			int count, int *eof, void *data)
{
	int len = cpumask_scnprintf(page, count, irq_affinity[(long)data]);
	if (count - len < 2)
		return -EINVAL;
	len += sprintf(page + len, "\n");
	return len;
}

static int irq_affinity_write_proc (struct file *file, const char *buffer,
					unsigned long count, void *data)
{
	int irq = (long) data, full_count = count, err;
	cpumask_t new_value, tmp;

	if (!irq_desc[irq].handler->set_affinity)
		return -EIO;

	err = cpumask_parse(buffer, count, new_value);

#ifdef CONFIG_SMP
	/*
	 * Do not allow disabling IRQs completely - it's a too easy
	 * way to make the system unusable accidentally :-) At least
	 * one online CPU still has to be targeted.
	 */
	cpus_and(tmp, new_value, cpu_online_map);
	if (cpus_empty(tmp))
		return -EINVAL;
#endif

	irq_affinity[irq] = new_value;
	irq_desc[irq].handler->set_affinity(irq, new_value);

	return full_count;
}

static int prof_cpu_mask_read_proc (char *page, char **start, off_t off,
			int count, int *eof, void *data)
{
	int len = cpumask_scnprintf(page, count, *(cpumask_t *)data);
	if (count - len < 2)
		return -EINVAL;
	len += sprintf(page + len, "\n");
	return len;
}

static int prof_cpu_mask_write_proc (struct file *file, const char *buffer,
					unsigned long count, void *data)
{
	cpumask_t *mask = (cpumask_t *)data, new_value;
	unsigned long full_count = count, err;

	err = cpumask_parse(buffer, count, new_value);
	if (err)
		return err;

	*mask = new_value;
	return full_count;
}

#define MAX_NAMELEN 10

static void register_irq_proc (unsigned int irq)
{
	struct proc_dir_entry *entry;
	char name [MAX_NAMELEN];

	if (!root_irq_dir || (irq_desc[irq].handler == &no_irq_type) ||
	    irq_dir[irq])
		return;

	memset(name, 0, MAX_NAMELEN);
	sprintf(name, "%d", irq);

	/* create /proc/irq/1234 */
	irq_dir[irq] = proc_mkdir(name, root_irq_dir);

	/* create /proc/irq/1234/smp_affinity */
	entry = create_proc_entry("smp_affinity", 0600, irq_dir[irq]);

	entry->nlink = 1;
	entry->data = (void *)(long)irq;
	entry->read_proc = irq_affinity_read_proc;
	entry->write_proc = irq_affinity_write_proc;

	smp_affinity_entry[irq] = entry;
}

/* Read and written as a long */
cpumask_t prof_cpu_mask = CPU_MASK_ALL;

void __init init_irq_proc (void)
{
	struct proc_dir_entry *entry;
	int i;

	/* create /proc/irq */
	root_irq_dir = proc_mkdir("irq", 0);

	/* create /proc/irq/prof_cpu_mask */
	entry = create_proc_entry("prof_cpu_mask", 0600, root_irq_dir);

	entry->nlink = 1;
	entry->data = (void *)&prof_cpu_mask;
	entry->read_proc = prof_cpu_mask_read_proc;
	entry->write_proc = prof_cpu_mask_write_proc;

	/*
	 * Create entries for all existing IRQs.
	 */
	for (i = 0; i < NR_IRQS; i++)
		register_irq_proc(i);
}

static spinlock_t irq_spinlock = SPIN_LOCK_UNLOCKED;

unsigned long irq_lock(void)
{
	unsigned long flags;

	spin_lock_irqsave(&irq_spinlock, flags);
	return(flags);
}

void irq_unlock(unsigned long flags)
{
	spin_unlock_irqrestore(&irq_spinlock, flags);
}

unsigned long probe_irq_on(void)
{
	return(0);
}

EXPORT_SYMBOL(probe_irq_on);

int probe_irq_off(unsigned long val)
{
	return(0);
}

EXPORT_SYMBOL(probe_irq_off);

static unsigned int startup_SIGIO_irq(unsigned int irq)
{
	return(0);
}

static void shutdown_SIGIO_irq(unsigned int irq)
{
}

static void enable_SIGIO_irq(unsigned int irq)
{
}

static void disable_SIGIO_irq(unsigned int irq)
{
}

static void mask_and_ack_SIGIO(unsigned int irq)
{
}

static void end_SIGIO_irq(unsigned int irq)
{
}

static unsigned int startup_SIGVTALRM_irq(unsigned int irq)
{
	return(0);
}

static void shutdown_SIGVTALRM_irq(unsigned int irq)
{
}

static void enable_SIGVTALRM_irq(unsigned int irq)
{
}

static void disable_SIGVTALRM_irq(unsigned int irq)
{
}

static void mask_and_ack_SIGVTALRM(unsigned int irq)
{
}

static void end_SIGVTALRM_irq(unsigned int irq)
{
}

static struct hw_interrupt_type SIGIO_irq_type = {
	"SIGIO",
	startup_SIGIO_irq,
	shutdown_SIGIO_irq,
	enable_SIGIO_irq,
	disable_SIGIO_irq,
	mask_and_ack_SIGIO,
	end_SIGIO_irq,
	NULL
};

static struct hw_interrupt_type SIGVTALRM_irq_type = {
	"SIGVTALRM",
	startup_SIGVTALRM_irq,
	shutdown_SIGVTALRM_irq,
	enable_SIGVTALRM_irq,
	disable_SIGVTALRM_irq,
	mask_and_ack_SIGVTALRM,
	end_SIGVTALRM_irq,
	NULL
};

void __init init_IRQ(void)
{
	int i;

	irq_desc[TIMER_IRQ].status = IRQ_DISABLED;
	irq_desc[TIMER_IRQ].action = 0;
	irq_desc[TIMER_IRQ].depth = 1;
	irq_desc[TIMER_IRQ].handler = &SIGVTALRM_irq_type;
	enable_irq(TIMER_IRQ);
	for(i=1;i<NR_IRQS;i++){
		irq_desc[i].status = IRQ_DISABLED;
		irq_desc[i].action = 0;
		irq_desc[i].depth = 1;
		irq_desc[i].handler = &SIGIO_irq_type;
		enable_irq(i);
	}
	init_irq_signals(0);
}

/*
 * Overrides for Emacs so that we follow Linus's tabbing style.
 * Emacs will notice this stuff at the end of the file and automatically
 * adjust the settings for this buffer only.  This must remain at the end
 * of the file.
 * ---------------------------------------------------------------------------
 * Local variables:
 * c-file-style: "linux"
 * End:
 */