nmi_debug.c

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/*
 * Copyright (C) 2007 Atmel Corporation
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/delay.h>
#include <linux/kdebug.h>
#include <linux/notifier.h>
#include <linux/sched.h>

#include <asm/irq.h>

enum nmi_action {
    NMI_SHOW_STATE  = 1 << 0,
    NMI_SHOW_REGS   = 1 << 1,
    NMI_DIE     = 1 << 2,
    NMI_DEBOUNCE    = 1 << 3,
};

static unsigned long nmi_actions;

static int nmi_debug_notify(struct notifier_block *self,
        unsigned long val, void *data)
{
    struct die_args *args = data;

    if (likely(val != DIE_NMI))
        return NOTIFY_DONE;

    if (nmi_actions & NMI_SHOW_STATE)
        show_state();
    if (nmi_actions & NMI_SHOW_REGS)
        show_regs(args->regs);
    if (nmi_actions & NMI_DEBOUNCE)
        mdelay(10);
    if (nmi_actions & NMI_DIE)
        return NOTIFY_BAD;

    return NOTIFY_OK;
}

static struct notifier_block nmi_debug_nb = {
    .notifier_call = nmi_debug_notify,
};

static int __init nmi_debug_setup(char *str)
{
    char *p, *sep;

    register_die_notifier(&nmi_debug_nb);
    if (nmi_enable()) {
        printk(KERN_WARNING "Unable to enable NMI.\n");
        return 0;
    }

    if (*str != '=')
        return 0;

    for (p = str + 1; *p; p = sep + 1) {
        sep = strchr(p, ',');
        if (sep)
            *sep = 0;
        if (strcmp(p, "state") == 0)
            nmi_actions |= NMI_SHOW_STATE;
        else if (strcmp(p, "regs") == 0)
            nmi_actions |= NMI_SHOW_REGS;
        else if (strcmp(p, "debounce") == 0)
            nmi_actions |= NMI_DEBOUNCE;
        else if (strcmp(p, "die") == 0)
            nmi_actions |= NMI_DIE;
        else
            printk(KERN_WARNING "NMI: Unrecognized action `%s'\n",
                p);
        if (!sep)
            break;
    }

    return 0;
}
__setup("nmi_debug", nmi_debug_setup);