/*
 *  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.
 */

#include <linux/errno.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/string.h>

/* For archs that don't support NO_IRQ (such as x86), provide a dummy value */
#ifndef NO_IRQ
#define NO_IRQ 0
#endif

/**
 * irq_of_parse_and_map - Parse and map an interrupt into linux virq space
 * @device: 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_map_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_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);

/**
 * 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;
}

/**
 * of_irq_map_raw - Low level interrupt tree parsing
 * @parent:     the device interrupt parent
 * @intspec:    interrupt specifier ("interrupts" property of the device)
 * @ointsize:   size of the passed in interrupt specifier
 * @addr:       address specifier (start of "reg" property of the device)
 * @out_irq:    structure of_irq filled 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.
 */
int of_irq_map_raw(struct device_node *parent, const __be32 *intspec,
                   u32 ointsize, const __be32 *addr, struct of_irq *out_irq)
{
        struct device_node *ipar, *tnode, *old = NULL, *newpar = NULL;
        const __be32 *tmp, *imap, *imask;
        u32 intsize = 1, addrsize, newintsize = 0, newaddrsize = 0;
        int imaplen, match, i;

        pr_debug("of_irq_map_raw: par=%s,intspec=[0x%08x 0x%08x...],ointsize=%d\n",
                 parent->full_name, be32_to_cpup(intspec),
                 be32_to_cpup(intspec + 1), ointsize);

        ipar = of_node_get(parent);

        /* 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_map_raw: ipar=%s, size=%d\n", ipar->full_name, intsize);

        if (ointsize != 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);

        /* 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");
                        for (i = 0; i < intsize; i++)
                                out_irq->specifier[i] =
                                                of_read_number(intspec +i, 1);
                        out_irq->size = intsize;
                        out_irq->controller = ipar;
                        of_node_put(old);
                        return 0;
                }

                /* 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 we were passed no "reg" property and we attempt to parse
                 * an interrupt-map, then #address-cells must be 0.
                 * Fail if it's not.
                 */
                if (addr == NULL && addrsize != 0) {
                        pr_debug(" -> no reg passed in when needed !\n");
                        goto fail;
                }

                /* Parse interrupt-map */
                match = 0;
                while (imaplen > (addrsize + intsize + 1) && !match) {
                        /* Compare specifiers */
                        match = 1;
                        for (i = 0; i < addrsize && match; ++i) {
                                u32 mask = imask ? imask[i] : 0xffffffffu;
                                match = ((addr[i] ^ imap[i]) & mask) == 0;
                        }
                        for (; i < (addrsize + intsize) && match; ++i) {
                                u32 mask = imask ? imask[i] : 0xffffffffu;
                                match =
                                   ((intspec[i-addrsize] ^ imap[i]) & mask) == 0;
                        }
                        imap += addrsize + intsize;
                        imaplen -= addrsize + intsize;

                        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
                                newpar = of_find_node_by_phandle(be32_to_cpup(imap));
                        imap++;
                        --imaplen;

                        /* Check if not found */
                        if (newpar == NULL) {
                                pr_debug(" -> imap parent not found !\n");
                                goto fail;
                        }

                        /* Get #interrupt-cells and #address-cells of new
                         * parent
                         */
                        tmp = of_get_property(newpar, "#interrupt-cells", NULL);
                        if (tmp == NULL) {
                                pr_debug(" -> parent lacks #interrupt-cells!\n");
                                goto fail;
                        }
                        newintsize = be32_to_cpu(*tmp);
                        tmp = of_get_property(newpar, "#address-cells", NULL);
                        newaddrsize = (tmp == NULL) ? 0 : be32_to_cpu(*tmp);

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

                        /* Check for malformed properties */
                        if (imaplen < (newaddrsize + newintsize))
                                goto fail;

                        imap += newaddrsize + newintsize;
                        imaplen -= newaddrsize + newintsize;

                        pr_debug(" -> imaplen=%d\n", imaplen);
                }
                if (!match)
                        goto fail;

                of_node_put(old);
                old = of_node_get(newpar);
                addrsize = newaddrsize;
                intsize = newintsize;
                intspec = imap - intsize;
                addr = intspec - addrsize;

        skiplevel:
                /* Iterate again with new parent */
                pr_debug(" -> new parent: %s\n", newpar ? newpar->full_name : "<>");
                of_node_put(ipar);
                ipar = newpar;
                newpar = NULL;
        }
 fail:
        of_node_put(ipar);
        of_node_put(old);
        of_node_put(newpar);

        return -EINVAL;
}
EXPORT_SYMBOL_GPL(of_irq_map_raw);

/**
 * of_irq_map_one - Resolve an interrupt for a device
 * @device: the device whose interrupt is to be resolved
 * @index: index of the interrupt to resolve
 * @out_irq: structure of_irq filled by this function
 *
 * This function resolves an interrupt, walking the tree, for a given
 * device-tree node. It's the high level pendant to of_irq_map_raw().
 */
int of_irq_map_one(struct device_node *device, int index, struct of_irq *out_irq)
{
        struct device_node *p;
        const __be32 *intspec, *tmp, *addr;
        u32 intsize, intlen;
        int res = -EINVAL;

        pr_debug("of_irq_map_one: dev=%s, index=%d\n", device->full_name, index);

        /* OldWorld mac stuff is "special", handle out of line */
        if (of_irq_workarounds & OF_IMAP_OLDWORLD_MAC)
                return of_irq_map_oldworld(device, index, out_irq);

        /* Get the interrupts property */
        intspec = of_get_property(device, "interrupts", &intlen);
        if (intspec == NULL)
                return -EINVAL;
        intlen /= sizeof(*intspec);

        pr_debug(" intspec=%d intlen=%d\n", be32_to_cpup(intspec), intlen);

        /* Get the reg property (if any) */
        addr = of_get_property(device, "reg", NULL);

        /* Look for the interrupt parent. */
        p = of_irq_find_parent(device);
        if (p == NULL)
                return -EINVAL;

        /* Get size of interrupt specifier */
        tmp = of_get_property(p, "#interrupt-cells", NULL);
        if (tmp == NULL)
                goto out;
        intsize = be32_to_cpu(*tmp);

        pr_debug(" intsize=%d intlen=%d\n", intsize, intlen);

        /* Check index */
        if ((index + 1) * intsize > intlen)
                goto out;

        /* Get new specifier and map it */
        res = of_irq_map_raw(p, intspec + index * intsize, intsize,
                             addr, out_irq);
 out:
        of_node_put(p);
        return res;
}
EXPORT_SYMBOL_GPL(of_irq_map_one);

/**
 * of_irq_to_resource - Decode a node's IRQ and return it as a resource
 * @dev: pointer to device tree node
 * @index: zero-based index of the irq
 * @r: pointer to resource structure to return result into.
 */
int of_irq_to_resource(struct device_node *dev, int index, struct resource *r)
{
        int irq = irq_of_parse_and_map(dev, index);

        /* Only dereference the resource if both the
         * resource and the irq are valid. */
        if (r && irq != NO_IRQ) {
                r->start = r->end = irq;
                r->flags = IORESOURCE_IRQ;
                r->name = dev->full_name;
        }

        return irq;
}
EXPORT_SYMBOL_GPL(of_irq_to_resource);

/**
 * of_irq_count - Count the number of IRQs a node uses
 * @dev: pointer to device tree node
 */
int of_irq_count(struct device_node *dev)
{
        int nr = 0;

        while (of_irq_to_resource(dev, nr, NULL) != NO_IRQ)
                nr++;

        return nr;
}

/**
 * of_irq_to_resource_table - Fill in resource table with node's IRQ info
 * @dev: pointer to device tree node
 * @res: array of resources to fill in
 * @nr_irqs: the number of IRQs (and upper bound for num of @res elements)
 *
 * Returns the size of the filled in table (up to @nr_irqs).
 */
int of_irq_to_resource_table(struct device_node *dev, struct resource *res,
                int nr_irqs)
{
        int i;

        for (i = 0; i < nr_irqs; i++, res++)
                if (of_irq_to_resource(dev, i, res) == NO_IRQ)
                        break;

        return i;
}