irq.c

linux-2.6.15.6

		irqreturn_t (*handler)(int, void *, struct pt_regs *),
		unsigned long irqflags,
		const char * devname,
		void *dev_id)
{
	int retval;
	struct irqaction *action;

#if 1
	/*
	 * Sanity-check: shared interrupts should REALLY 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) {
		if (!dev_id)
			printk("Bad boy: %s (at 0x%x) called us without a dev_id!\n",
			       devname, (&irq)[-1]);
	}
#endif

	if ((irq >> NR_IRQ_LOG2_ACTIONS_PER_GROUP) >= NR_IRQ_GROUPS)
		return -EINVAL;
	if (!handler)
		return -EINVAL;

	action = (struct irqaction *) kmalloc(sizeof(struct irqaction), GFP_KERNEL);
	if (!action)
		return -ENOMEM;

	action->handler = handler;
	action->flags = irqflags;
	action->mask = CPU_MASK_NONE;
	action->name = devname;
	action->next = NULL;
	action->dev_id = dev_id;

	retval = setup_irq(irq, action);
	if (retval)
		kfree(action);
	return retval;
}

/**
 *	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)
{
	struct irq_source *source;
	struct irq_group *group;
	struct irq_level *level;
	struct irqaction **p, **pp;
	unsigned long flags;

	if ((irq >> NR_IRQ_LOG2_ACTIONS_PER_GROUP) >= NR_IRQ_GROUPS)
		return;

	group = irq_groups[irq >> NR_IRQ_LOG2_ACTIONS_PER_GROUP];
	if (!group)
		BUG();

	source = group->sources[irq & (NR_IRQ_ACTIONS_PER_GROUP - 1)];
	if (!source)
		BUG();

	level = source->level;
	p = &group->actions[irq & (NR_IRQ_ACTIONS_PER_GROUP - 1)];

	spin_lock_irqsave(&level->lock, flags);

	for (pp = p; *pp; pp = &(*pp)->next) {
		struct irqaction *action = *pp;

		if (action->dev_id != dev_id)
			continue;

		/* found it - remove from the list of entries */
		*pp = action->next;

		level->usage--;

		if (p == pp && group->control)
			group->control(group, irq & (NR_IRQ_ACTIONS_PER_GROUP - 1), 0);

		if (level->usage == 0)
			__set_MASK(level - frv_irq_levels);

		spin_unlock_irqrestore(&level->lock,flags);

#ifdef CONFIG_SMP
		/* Wait to make sure it's not being used on another CPU */
		while (desc->status & IRQ_INPROGRESS)
			barrier();
#endif
		kfree(action);
		return;
	}
}

/*
 * IRQ autodetection code..
 *
 * This depends on the fact that any interrupt that comes in on to an
 * unassigned IRQ will cause GxICR_DETECT to be set
 */

static DECLARE_MUTEX(probe_sem);

/**
 *	probe_irq_on	- begin an interrupt autodetect
 *
 *	Commence probing for an interrupt. The interrupts are scanned
 *	and a mask of potential interrupt lines is returned.
 *
 */

unsigned long probe_irq_on(void)
{
	down(&probe_sem);
	return 0;
}

/*
 * Return a mask of triggered interrupts (this
 * can handle only legacy ISA interrupts).
 */

/**
 *	probe_irq_mask - scan a bitmap of interrupt lines
 *	@val:	mask of interrupts to consider
 *
 *	Scan the ISA bus interrupt lines and return a bitmap of
 *	active interrupts. The interrupt probe logic state is then
 *	returned to its previous value.
 *
 *	Note: we need to scan all the irq's even though we will
 *	only return ISA irq numbers - just so that we reset them
 *	all to a known state.
 */
unsigned int probe_irq_mask(unsigned long xmask)
{
	up(&probe_sem);
	return 0;
}

/*
 * Return the one interrupt that triggered (this can
 * handle any interrupt source).
 */

/**
 *	probe_irq_off	- end an interrupt autodetect
 *	@xmask: mask of potential interrupts (unused)
 *
 *	Scans the unused interrupt lines and returns the line which
 *	appears to have triggered the interrupt. If no interrupt was
 *	found then zero is returned. If more than one interrupt is
 *	found then minus the first candidate is returned to indicate
 *	their is doubt.
 *
 *	The interrupt probe logic state is returned to its previous
 *	value.
 *
 *	BUGS: When used in a module (which arguably shouldnt happen)
 *	nothing prevents two IRQ probe callers from overlapping. The
 *	results of this are non-optimal.
 */

int probe_irq_off(unsigned long xmask)
{
	up(&probe_sem);
	return -1;
}

/* this was setup_x86_irq but it seems pretty generic */
int setup_irq(unsigned int irq, struct irqaction *new)
{
	struct irq_source *source;
	struct irq_group *group;
	struct irq_level *level;
	struct irqaction **p, **pp;
	unsigned long flags;

	group = irq_groups[irq >> NR_IRQ_LOG2_ACTIONS_PER_GROUP];
	if (!group)
		BUG();

	source = group->sources[irq & (NR_IRQ_ACTIONS_PER_GROUP - 1)];
	if (!source)
		BUG();

	level = source->level;

	p = &group->actions[irq & (NR_IRQ_ACTIONS_PER_GROUP - 1)];

	/*
	 * 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);
	}

	/* must juggle the interrupt processing stuff with interrupts disabled */
	spin_lock_irqsave(&level->lock, flags);

	/* can't share interrupts unless all parties agree to */
	if (level->usage != 0 && !(level->flags & new->flags & SA_SHIRQ)) {
		spin_unlock_irqrestore(&level->lock,flags);
		return -EBUSY;
	}

	/* add new interrupt at end of irq queue */
	pp = p;
	while (*pp)
		pp = &(*pp)->next;

	*pp = new;

	level->usage++;
	level->flags = new->flags;

	/* turn the interrupts on */
	if (level->usage == 1)
		__clr_MASK(level - frv_irq_levels);

	if (p == pp && group->control)
		group->control(group, irq & (NR_IRQ_ACTIONS_PER_GROUP - 1), 1);

	spin_unlock_irqrestore(&level->lock, flags);
	register_irq_proc(irq);
	return 0;
}

static struct proc_dir_entry * root_irq_dir;
static struct proc_dir_entry * irq_dir [NR_IRQS];

#define HEX_DIGITS 8

static unsigned int parse_hex_value (const char *buffer,
				     unsigned long count, unsigned long *ret)
{
	unsigned char hexnum [HEX_DIGITS];
	unsigned long value;
	int i;

	if (!count)
		return -EINVAL;
	if (count > HEX_DIGITS)
		count = HEX_DIGITS;
	if (copy_from_user(hexnum, buffer, count))
		return -EFAULT;

	/*
	 * Parse the first 8 characters as a hex string, any non-hex char
	 * is end-of-string. '00e1', 'e1', '00E1', 'E1' are all the same.
	 */
	value = 0;

	for (i = 0; i < count; i++) {
		unsigned int c = hexnum[i];

		switch (c) {
			case '0' ... '9': c -= '0'; break;
			case 'a' ... 'f': c -= 'a'-10; break;
			case 'A' ... 'F': c -= 'A'-10; break;
		default:
			goto out;
		}
		value = (value << 4) | c;
	}
out:
	*ret = value;
	return 0;
}


static int prof_cpu_mask_read_proc (char *page, char **start, off_t off,
			int count, int *eof, void *data)
{
	unsigned long *mask = (unsigned long *) data;
	if (count < HEX_DIGITS+1)
		return -EINVAL;
	return sprintf (page, "%08lx\n", *mask);
}

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

	show_state();
	err = parse_hex_value(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)
{
	char name [MAX_NAMELEN];

	if (!root_irq_dir || 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);
}

unsigned long prof_cpu_mask = -1;

void 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);
	if (!entry)
	    return;

	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);
}

/*****************************************************************************/
/*
 * initialise the interrupt system
 */
void __init init_IRQ(void)
{
	route_cpu_irqs();
	fpga_init();
#ifdef CONFIG_FUJITSU_MB93493
	route_mb93493_irqs();
#endif
} /* end init_IRQ() */