path: root/drivers/of/irq.c

/*
 *  Derived from arch/i386/kernel/irq.c
 *    Copyright (C) 1992 Linus Torvalds
 *  Adapted from arch/i386 by Gary Thomas
 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
 *  Updated and modified by Cort Dougan <cort@fsmlabs.com>
 *    Copyright (C) 1996-2001 Cort Dougan
 *  Adapted for Power Macintosh by Paul Mackerras
 *    Copyright (C) 1996 Paul Mackerras (paulus@cs.anu.edu.au)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 *
 * This file contains the code used to make IRQ descriptions in the
 * device tree to actual irq numbers on an interrupt controller
 * driver.
 */

#define pr_fmt(fmt)	"OF: " fmt

#include <linux/device.h>
#include <linux/errno.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/of_pci.h>
#include <linux/string.h>
#include <linux/slab.h>

/**
 * irq_of_parse_and_map - Parse and map an interrupt into linux virq space
 * @dev: Device node of the device whose interrupt is to be mapped
 * @index: Index of the interrupt to map
 *
 * This function is a wrapper that chains of_irq_parse_one() and
 * irq_create_of_mapping() to make things easier to callers
 */
unsigned int irq_of_parse_and_map(struct device_node *dev, int index)
{
	struct of_phandle_args oirq;

	if (of_irq_parse_one(dev, index, &oirq))
		return 0;

	return irq_create_of_mapping(&oirq);
}
EXPORT_SYMBOL_GPL(irq_of_parse_and_map);

/**
 * of_irq_find_parent - Given a device node, find its interrupt parent node
 * @child: pointer to device node
 *
 * Returns a pointer to the interrupt parent node, or NULL if the interrupt
 * parent could not be determined.
 */
struct device_node *of_irq_find_parent(struct device_node *child)
{
	struct device_node *p;
	const __be32 *parp;

	if (!of_node_get(child))
		return NULL;

	do {
		parp = of_get_property(child, "interrupt-parent", NULL);
		if (parp == NULL)
			p = of_get_parent(child);
		else {
			if (of_irq_workarounds & OF_IMAP_NO_PHANDLE)
				p = of_node_get(of_irq_dflt_pic);
			else
				p = of_find_node_by_phandle(be32_to_cpup(parp));
		}
		of_node_put(child);
		child = p;
	} while (p && of_get_property(p, "#interrupt-cells", NULL) == NULL);

	return p;
}
EXPORT_SYMBOL_GPL(of_irq_find_parent);

/**
 * of_irq_parse_raw - Low level interrupt tree parsing
 * @parent:	the device interrupt parent
 * @addr:	address specifier (start of "reg" property of the device) in be32 format
 * @out_irq:	structure of_irq updated by this function
 *
 * Returns 0 on success and a negative number on error
 *
 * This function is a low-level interrupt tree walking function. It
 * can be used to do a partial walk with synthetized reg and interrupts
 * properties, for example when resolving PCI interrupts when no device
 * node exist for the parent. It takes an interrupt specifier structure as
 * input, walks the tree looking for any interrupt-map properties, translates
 * the specifier for each map, and then returns the translated map.
 */
int of_irq_parse_raw(const __be32 *addr, struct of_phandle_args *out_irq)
{
	struct device_node *ipar, *tnode, *old = NULL, *newpar = NULL;
	__be32 initial_match_array[MAX_PHANDLE_ARGS];
	const __be32 *match_array = initial_match_array;
	const __be32 *tmp, *imap, *imask, dummy_imask[] = { [0 ... MAX_PHANDLE_ARGS] = ~0 };
	u32 intsize = 1, addrsize, newintsize = 0, newaddrsize = 0;
	int imaplen, match, i;

#ifdef DEBUG
	of_print_phandle_args("of_irq_parse_raw: ", out_irq);
#endif

	ipar = of_node_get(out_irq->np);

	/* First get the #interrupt-cells property of the current cursor
	 * that tells us how to interpret the passed-in intspec. If there
	 * is none, we are nice and just walk up the tree
	 */
	do {
		tmp = of_get_property(ipar, "#interrupt-cells", NULL);
		if (tmp != NULL) {
			intsize = be32_to_cpu(*tmp);
			break;
		}
		tnode = ipar;
		ipar = of_irq_find_parent(ipar);
		of_node_put(tnode);
	} while (ipar);
	if (ipar == NULL) {
		pr_debug(" -> no parent found !\n");
		goto fail;
	}

	pr_debug("of_irq_parse_raw: ipar=%s, size=%d\n", of_node_full_name(ipar), intsize);

	if (out_irq->args_count != intsize)
		return -EINVAL;

	/* Look for this #address-cells. We have to implement the old linux
	 * trick of looking for the parent here as some device-trees rely on it
	 */
	old = of_node_get(ipar);
	do {
		tmp = of_get_property(old, "#address-cells", NULL);
		tnode = of_get_parent(old);
		of_node_put(old);
		old = tnode;
	} while (old && tmp == NULL);
	of_node_put(old);
	old = NULL;
	addrsize = (tmp == NULL) ? 2 : be32_to_cpu(*tmp);

	pr_debug(" -> addrsize=%d\n", addrsize);

	/* Range check so that the temporary buffer doesn't overflow */
	if (WARN_ON(addrsize + intsize > MAX_PHANDLE_ARGS))
		goto fail;

	/* Precalculate the match array - this simplifies match loop */
	for (i = 0; i < addrsize; i++)
		initial_match_array[i] = addr ? addr[i] : 0;
	for (i = 0; i < intsize; i++)
		initial_match_array[addrsize + i] = cpu_to_be32(out_irq->args[i]);

	/* Now start the actual "proper" walk of the interrupt tree */
	while (ipar != NULL) {
		/* Now check if cursor is an interrupt-controller and if it is
		 * then we are done
		 */
		if (of_get_property(ipar, "interrupt-controller", NULL) !=
				NULL) {
			pr_debug(" -> got it !\n");
			return 0;
		}

		/*
		 * interrupt-map parsing does not work without a reg
		 * property when #address-cells != 0
		 */
		if (addrsize && !addr) {
			pr_debug(" -> no reg passed in when needed !\n");
			goto fail;
		}

		/* Now look for an interrupt-map */
		imap = of_get_property(ipar, "interrupt-map", &imaplen);
		/* No interrupt map, check for an interrupt parent */
		if (imap == NULL) {
			pr_debug(" -> no map, getting parent\n");
			newpar = of_irq_find_parent(ipar);
			goto skiplevel;
		}
		imaplen /= sizeof(u32);

		/* Look for a mask */
		imask = of_get_property(ipar, "interrupt-map-mask", NULL);
		if (!imask)
			imask = dummy_imask;

		/* Parse interrupt-map */
		match = 0;
		while (imaplen > (addrsize + intsize + 1) && !match) {
			/* Compare specifiers */
			match = 1;
			for (i = 0; i < (addrsize + intsize); i++, imaplen--)
				match &= !((match_array[i] ^ *imap++) & imask[i]);

			pr_debug(" -> match=%d (imaplen=%d)\n", match, imaplen);

			/* Get the interrupt parent */
			if (of_irq_workarounds & OF_IMAP_NO_PHANDLE)
				newpar = of_node_get(of_irq_dflt_pic);
			else