irq.c

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/*
 *  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 ([email protected])
 *  Updated and modified by Cort Dougan <[email protected]>
 *    Copyright (C) 1996-2001 Cort Dougan
 *  Adapted for Power Macintosh by Paul Mackerras
 *    Copyright (C) 1996 Paul Mackerras ([email protected])
 *
 * 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/list.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/string.h>
#include <linux/slab.h>

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 0;

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

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;
}

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) {
                __be32 mask = imask ? imask[i]
                            : cpu_to_be32(0xffffffffu);
                match = ((addr[i] ^ imap[i]) & mask) == 0;
            }
            for (; i < (addrsize + intsize) && match; ++i) {
                __be32 mask = imask ? imask[i]
                            : cpu_to_be32(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", of_node_full_name(newpar));
        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);

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);

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) {
        const char *name = NULL;

        /*
         * Get optional "interrupts-names" property to add a name
         * to the resource.
         */
        of_property_read_string_index(dev, "interrupt-names", index,
                          &name);

        r->start = r->end = irq;
        r->flags = IORESOURCE_IRQ;
        r->name = name ? name : dev->full_name;
    }

    return irq;
}
EXPORT_SYMBOL_GPL(of_irq_to_resource);

int of_irq_count(struct device_node *dev)
{
    int nr = 0;

    while (of_irq_to_resource(dev, nr, NULL))
        nr++;

    return nr;
}

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))
            break;

    return i;
}
EXPORT_SYMBOL_GPL(of_irq_to_resource_table);

struct intc_desc {
    struct list_head    list;
    struct device_node  *dev;
    struct device_node  *interrupt_parent;
};

void __init of_irq_init(const struct of_device_id *matches)
{
    struct device_node *np, *parent = NULL;
    struct intc_desc *desc, *temp_desc;
    struct list_head intc_desc_list, intc_parent_list;

    INIT_LIST_HEAD(&intc_desc_list);
    INIT_LIST_HEAD(&intc_parent_list);

    for_each_matching_node(np, matches) {
        if (!of_find_property(np, "interrupt-controller", NULL))
            continue;
        /*
         * Here, we allocate and populate an intc_desc with the node
         * pointer, interrupt-parent device_node etc.
         */
        desc = kzalloc(sizeof(*desc), GFP_KERNEL);
        if (WARN_ON(!desc))
            goto err;

        desc->dev = np;
        desc->interrupt_parent = of_irq_find_parent(np);
        if (desc->interrupt_parent == np)
            desc->interrupt_parent = NULL;
        list_add_tail(&desc->list, &intc_desc_list);
    }

    /*
     * The root irq controller is the one without an interrupt-parent.
     * That one goes first, followed by the controllers that reference it,
     * followed by the ones that reference the 2nd level controllers, etc.
     */
    while (!list_empty(&intc_desc_list)) {
        /*
         * Process all controllers with the current 'parent'.
         * First pass will be looking for NULL as the parent.
         * The assumption is that NULL parent means a root controller.
         */
        list_for_each_entry_safe(desc, temp_desc, &intc_desc_list, list) {
            const struct of_device_id *match;
            int ret;
            of_irq_init_cb_t irq_init_cb;

            if (desc->interrupt_parent != parent)
                continue;

            list_del(&desc->list);
            match = of_match_node(matches, desc->dev);
            if (WARN(!match->data,
                "of_irq_init: no init function for %s\n",
                match->compatible)) {
                kfree(desc);
                continue;
            }

            pr_debug("of_irq_init: init %s @ %p, parent %p\n",
                 match->compatible,
                 desc->dev, desc->interrupt_parent);
            irq_init_cb = (of_irq_init_cb_t)match->data;
            ret = irq_init_cb(desc->dev, desc->interrupt_parent);
            if (ret) {
                kfree(desc);
                continue;
            }

            /*
             * This one is now set up; add it to the parent list so
             * its children can get processed in a subsequent pass.
             */
            list_add_tail(&desc->list, &intc_parent_list);
        }

        /* Get the next pending parent that might have children */
        desc = list_first_entry(&intc_parent_list, typeof(*desc), list);
        if (list_empty(&intc_parent_list) || !desc) {
            pr_err("of_irq_init: children remain, but no parents\n");
            break;
        }
        list_del(&desc->list);
        parent = desc->dev;
        kfree(desc);
    }

    list_for_each_entry_safe(desc, temp_desc, &intc_parent_list, list) {
        list_del(&desc->list);
        kfree(desc);
    }
err:
    list_for_each_entry_safe(desc, temp_desc, &intc_desc_list, list) {
        list_del(&desc->list);
        kfree(desc);
    }
}