irq.c

linux 内核源代码

	pr_debug("irq: Default host set to @0x%p\n", host);

	irq_default_host = host;
}

void irq_set_virq_count(unsigned int count)
{
	pr_debug("irq: Trying to set virq count to %d\n", count);

	BUG_ON(count < NUM_ISA_INTERRUPTS);
	if (count < NR_IRQS)
		irq_virq_count = count;
}

/* radix tree not lockless safe ! we use a brlock-type mecanism
 * for now, until we can use a lockless radix tree
 */
static void irq_radix_wrlock(unsigned long *flags)
{
	unsigned int cpu, ok;

	spin_lock_irqsave(&irq_big_lock, *flags);
	irq_radix_writer = 1;
	smp_mb();
	do {
		barrier();
		ok = 1;
		for_each_possible_cpu(cpu) {
			if (per_cpu(irq_radix_reader, cpu)) {
				ok = 0;
				break;
			}
		}
		if (!ok)
			cpu_relax();
	} while(!ok);
}

static void irq_radix_wrunlock(unsigned long flags)
{
	smp_wmb();
	irq_radix_writer = 0;
	spin_unlock_irqrestore(&irq_big_lock, flags);
}

static void irq_radix_rdlock(unsigned long *flags)
{
	local_irq_save(*flags);
	__get_cpu_var(irq_radix_reader) = 1;
	smp_mb();
	if (likely(irq_radix_writer == 0))
		return;
	__get_cpu_var(irq_radix_reader) = 0;
	smp_wmb();
	spin_lock(&irq_big_lock);
	__get_cpu_var(irq_radix_reader) = 1;
	spin_unlock(&irq_big_lock);
}

static void irq_radix_rdunlock(unsigned long flags)
{
	__get_cpu_var(irq_radix_reader) = 0;
	local_irq_restore(flags);
}

static int irq_setup_virq(struct irq_host *host, unsigned int virq,
			    irq_hw_number_t hwirq)
{
	/* Clear IRQ_NOREQUEST flag */
	get_irq_desc(virq)->status &= ~IRQ_NOREQUEST;

	/* map it */
	smp_wmb();
	irq_map[virq].hwirq = hwirq;
	smp_mb();

	if (host->ops->map(host, virq, hwirq)) {
		pr_debug("irq: -> mapping failed, freeing\n");
		irq_free_virt(virq, 1);
		return -1;
	}

	return 0;
}

unsigned int irq_create_direct_mapping(struct irq_host *host)
{
	unsigned int virq;

	if (host == NULL)
		host = irq_default_host;

	BUG_ON(host == NULL);
	WARN_ON(host->revmap_type != IRQ_HOST_MAP_NOMAP);

	virq = irq_alloc_virt(host, 1, 0);
	if (virq == NO_IRQ) {
		pr_debug("irq: create_direct virq allocation failed\n");
		return NO_IRQ;
	}

	pr_debug("irq: create_direct obtained virq %d\n", virq);

	if (irq_setup_virq(host, virq, virq))
		return NO_IRQ;

	return virq;
}

unsigned int irq_create_mapping(struct irq_host *host,
				irq_hw_number_t hwirq)
{
	unsigned int virq, hint;

	pr_debug("irq: irq_create_mapping(0x%p, 0x%lx)\n", host, hwirq);

	/* Look for default host if nececssary */
	if (host == NULL)
		host = irq_default_host;
	if (host == NULL) {
		printk(KERN_WARNING "irq_create_mapping called for"
		       " NULL host, hwirq=%lx\n", hwirq);
		WARN_ON(1);
		return NO_IRQ;
	}
	pr_debug("irq: -> using host @%p\n", host);

	/* Check if mapping already exist, if it does, call
	 * host->ops->map() to update the flags
	 */
	virq = irq_find_mapping(host, hwirq);
	if (virq != NO_IRQ) {
		if (host->ops->remap)
			host->ops->remap(host, virq, hwirq);
		pr_debug("irq: -> existing mapping on virq %d\n", virq);
		return virq;
	}

	/* Get a virtual interrupt number */
	if (host->revmap_type == IRQ_HOST_MAP_LEGACY) {
		/* Handle legacy */
		virq = (unsigned int)hwirq;
		if (virq == 0 || virq >= NUM_ISA_INTERRUPTS)
			return NO_IRQ;
		return virq;
	} else {
		/* Allocate a virtual interrupt number */
		hint = hwirq % irq_virq_count;
		virq = irq_alloc_virt(host, 1, hint);
		if (virq == NO_IRQ) {
			pr_debug("irq: -> virq allocation failed\n");
			return NO_IRQ;
		}
	}
	pr_debug("irq: -> obtained virq %d\n", virq);

	if (irq_setup_virq(host, virq, hwirq))
		return NO_IRQ;

	return virq;
}
EXPORT_SYMBOL_GPL(irq_create_mapping);

unsigned int irq_create_of_mapping(struct device_node *controller,
				   u32 *intspec, unsigned int intsize)
{
	struct irq_host *host;
	irq_hw_number_t hwirq;
	unsigned int type = IRQ_TYPE_NONE;
	unsigned int virq;

	if (controller == NULL)
		host = irq_default_host;
	else
		host = irq_find_host(controller);
	if (host == NULL) {
		printk(KERN_WARNING "irq: no irq host found for %s !\n",
		       controller->full_name);
		return NO_IRQ;
	}

	/* If host has no translation, then we assume interrupt line */
	if (host->ops->xlate == NULL)
		hwirq = intspec[0];
	else {
		if (host->ops->xlate(host, controller, intspec, intsize,
				     &hwirq, &type))
			return NO_IRQ;
	}

	/* Create mapping */
	virq = irq_create_mapping(host, hwirq);
	if (virq == NO_IRQ)
		return virq;

	/* Set type if specified and different than the current one */
	if (type != IRQ_TYPE_NONE &&
	    type != (get_irq_desc(virq)->status & IRQF_TRIGGER_MASK))
		set_irq_type(virq, type);
	return virq;
}
EXPORT_SYMBOL_GPL(irq_create_of_mapping);

unsigned int irq_of_parse_and_map(struct device_node *dev, int index)
{
	struct of_irq oirq;

	if (of_irq_map_one(dev, index, &oirq))
		return NO_IRQ;

	return irq_create_of_mapping(oirq.controller, oirq.specifier,
				     oirq.size);
}
EXPORT_SYMBOL_GPL(irq_of_parse_and_map);

void irq_dispose_mapping(unsigned int virq)
{
	struct irq_host *host;
	irq_hw_number_t hwirq;
	unsigned long flags;

	if (virq == NO_IRQ)
		return;

	host = irq_map[virq].host;
	WARN_ON (host == NULL);
	if (host == NULL)
		return;

	/* Never unmap legacy interrupts */
	if (host->revmap_type == IRQ_HOST_MAP_LEGACY)
		return;

	/* remove chip and handler */
	set_irq_chip_and_handler(virq, NULL, NULL);

	/* Make sure it's completed */
	synchronize_irq(virq);

	/* Tell the PIC about it */
	if (host->ops->unmap)
		host->ops->unmap(host, virq);
	smp_mb();

	/* Clear reverse map */
	hwirq = irq_map[virq].hwirq;
	switch(host->revmap_type) {
	case IRQ_HOST_MAP_LINEAR:
		if (hwirq < host->revmap_data.linear.size)
			host->revmap_data.linear.revmap[hwirq] = NO_IRQ;
		break;
	case IRQ_HOST_MAP_TREE:
		/* Check if radix tree allocated yet */
		if (host->revmap_data.tree.gfp_mask == 0)
			break;
		irq_radix_wrlock(&flags);
		radix_tree_delete(&host->revmap_data.tree, hwirq);
		irq_radix_wrunlock(flags);
		break;
	}

	/* Destroy map */
	smp_mb();
	irq_map[virq].hwirq = host->inval_irq;

	/* Set some flags */
	get_irq_desc(virq)->status |= IRQ_NOREQUEST;

	/* Free it */
	irq_free_virt(virq, 1);
}
EXPORT_SYMBOL_GPL(irq_dispose_mapping);

unsigned int irq_find_mapping(struct irq_host *host,
			      irq_hw_number_t hwirq)
{
	unsigned int i;
	unsigned int hint = hwirq % irq_virq_count;

	/* Look for default host if nececssary */
	if (host == NULL)
		host = irq_default_host;
	if (host == NULL)
		return NO_IRQ;

	/* legacy -> bail early */
	if (host->revmap_type == IRQ_HOST_MAP_LEGACY)
		return hwirq;

	/* Slow path does a linear search of the map */
	if (hint < NUM_ISA_INTERRUPTS)
		hint = NUM_ISA_INTERRUPTS;
	i = hint;
	do  {
		if (irq_map[i].host == host &&
		    irq_map[i].hwirq == hwirq)
			return i;
		i++;
		if (i >= irq_virq_count)
			i = NUM_ISA_INTERRUPTS;
	} while(i != hint);
	return NO_IRQ;
}
EXPORT_SYMBOL_GPL(irq_find_mapping);


unsigned int irq_radix_revmap(struct irq_host *host,
			      irq_hw_number_t hwirq)
{
	struct radix_tree_root *tree;
	struct irq_map_entry *ptr;
	unsigned int virq;
	unsigned long flags;

	WARN_ON(host->revmap_type != IRQ_HOST_MAP_TREE);

	/* Check if the radix tree exist yet. We test the value of
	 * the gfp_mask for that. Sneaky but saves another int in the
	 * structure. If not, we fallback to slow mode
	 */
	tree = &host->revmap_data.tree;
	if (tree->gfp_mask == 0)
		return irq_find_mapping(host, hwirq);

	/* Now try to resolve */
	irq_radix_rdlock(&flags);
	ptr = radix_tree_lookup(tree, hwirq);
	irq_radix_rdunlock(flags);

	/* Found it, return */
	if (ptr) {
		virq = ptr - irq_map;
		return virq;
	}

	/* If not there, try to insert it */
	virq = irq_find_mapping(host, hwirq);
	if (virq != NO_IRQ) {
		irq_radix_wrlock(&flags);
		radix_tree_insert(tree, hwirq, &irq_map[virq]);
		irq_radix_wrunlock(flags);
	}
	return virq;
}

unsigned int irq_linear_revmap(struct irq_host *host,
			       irq_hw_number_t hwirq)
{
	unsigned int *revmap;

	WARN_ON(host->revmap_type != IRQ_HOST_MAP_LINEAR);

	/* Check revmap bounds */
	if (unlikely(hwirq >= host->revmap_data.linear.size))
		return irq_find_mapping(host, hwirq);

	/* Check if revmap was allocated */
	revmap = host->revmap_data.linear.revmap;
	if (unlikely(revmap == NULL))
		return irq_find_mapping(host, hwirq);

	/* Fill up revmap with slow path if no mapping found */
	if (unlikely(revmap[hwirq] == NO_IRQ))
		revmap[hwirq] = irq_find_mapping(host, hwirq);

	return revmap[hwirq];
}

unsigned int irq_alloc_virt(struct irq_host *host,
			    unsigned int count,
			    unsigned int hint)
{
	unsigned long flags;
	unsigned int i, j, found = NO_IRQ;

	if (count == 0 || count > (irq_virq_count - NUM_ISA_INTERRUPTS))
		return NO_IRQ;

	spin_lock_irqsave(&irq_big_lock, flags);

	/* Use hint for 1 interrupt if any */
	if (count == 1 && hint >= NUM_ISA_INTERRUPTS &&
	    hint < irq_virq_count && irq_map[hint].host == NULL) {
		found = hint;
		goto hint_found;
	}

	/* Look for count consecutive numbers in the allocatable
	 * (non-legacy) space
	 */
	for (i = NUM_ISA_INTERRUPTS, j = 0; i < irq_virq_count; i++) {
		if (irq_map[i].host != NULL)
			j = 0;
		else
			j++;

		if (j == count) {
			found = i - count + 1;
			break;
		}
	}
	if (found == NO_IRQ) {
		spin_unlock_irqrestore(&irq_big_lock, flags);
		return NO_IRQ;
	}
 hint_found:
	for (i = found; i < (found + count); i++) {
		irq_map[i].hwirq = host->inval_irq;
		smp_wmb();
		irq_map[i].host = host;
	}
	spin_unlock_irqrestore(&irq_big_lock, flags);
	return found;
}

void irq_free_virt(unsigned int virq, unsigned int count)
{
	unsigned long flags;
	unsigned int i;

	WARN_ON (virq < NUM_ISA_INTERRUPTS);
	WARN_ON (count == 0 || (virq + count) > irq_virq_count);

	spin_lock_irqsave(&irq_big_lock, flags);
	for (i = virq; i < (virq + count); i++) {
		struct irq_host *host;

		if (i < NUM_ISA_INTERRUPTS ||
		    (virq + count) > irq_virq_count)
			continue;

		host = irq_map[i].host;
		irq_map[i].hwirq = host->inval_irq;
		smp_wmb();
		irq_map[i].host = NULL;
	}
	spin_unlock_irqrestore(&irq_big_lock, flags);
}

void irq_early_init(void)
{
	unsigned int i;

	for (i = 0; i < NR_IRQS; i++)
		get_irq_desc(i)->status |= IRQ_NOREQUEST;
}

/* We need to create the radix trees late */
static int irq_late_init(void)
{
	struct irq_host *h;
	unsigned long flags;

	irq_radix_wrlock(&flags);
	list_for_each_entry(h, &irq_hosts, link) {
		if (h->revmap_type == IRQ_HOST_MAP_TREE)
			INIT_RADIX_TREE(&h->revmap_data.tree, GFP_ATOMIC);
	}
	irq_radix_wrunlock(flags);

	return 0;
}
arch_initcall(irq_late_init);

#ifdef CONFIG_VIRQ_DEBUG
static int virq_debug_show(struct seq_file *m, void *private)
{
	unsigned long flags;
	irq_desc_t *desc;
	const char *p;
	char none[] = "none";
	int i;

	seq_printf(m, "%-5s  %-7s  %-15s  %s\n", "virq", "hwirq",
		      "chip name", "host name");

	for (i = 1; i < NR_IRQS; i++) {
		desc = get_irq_desc(i);
		spin_lock_irqsave(&desc->lock, flags);

		if (desc->action && desc->action->handler) {
			seq_printf(m, "%5d  ", i);
			seq_printf(m, "0x%05lx  ", virq_to_hw(i));

			if (desc->chip && desc->chip->typename)
				p = desc->chip->typename;
			else
				p = none;
			seq_printf(m, "%-15s  ", p);

			if (irq_map[i].host && irq_map[i].host->of_node)
				p = irq_map[i].host->of_node->full_name;
			else
				p = none;
			seq_printf(m, "%s\n", p);
		}

		spin_unlock_irqrestore(&desc->lock, flags);
	}

	return 0;
}

static int virq_debug_open(struct inode *inode, struct file *file)
{
	return single_open(file, virq_debug_show, inode->i_private);
}

static const struct file_operations virq_debug_fops = {
	.open = virq_debug_open,
	.read = seq_read,
	.llseek = seq_lseek,
	.release = single_release,
};

static int __init irq_debugfs_init(void)
{
	if (debugfs_create_file("virq_mapping", S_IRUGO, powerpc_debugfs_root,
				 NULL, &virq_debug_fops))
		return -ENOMEM;

	return 0;
}
__initcall(irq_debugfs_init);
#endif /* CONFIG_VIRQ_DEBUG */

#endif /* CONFIG_PPC_MERGE */

#ifdef CONFIG_PPC64
static int __init setup_noirqdistrib(char *str)
{
	distribute_irqs = 0;
	return 1;
}

__setup("noirqdistrib", setup_noirqdistrib);
#endif /* CONFIG_PPC64 */