/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1992, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This software was developed by the Computer Systems Engineering group
 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
 * contributed to Berkeley.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 */

#include <sys/cdefs.h>
#include "opt_ddb.h"

#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/linker.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/systm.h>

/*
 * Autoconfiguration subroutines.
 */

/*
 * "Interrupt driven config" functions.
 */
static STAILQ_HEAD(, intr_config_hook) intr_config_hook_list =
        STAILQ_HEAD_INITIALIZER(intr_config_hook_list);
static struct intr_config_hook *next_to_notify;
static struct mtx intr_config_hook_lock;
MTX_SYSINIT(intr_config_hook, &intr_config_hook_lock, "intr config", MTX_DEF);

/* ARGSUSED */
static void run_interrupt_driven_config_hooks(void);

/*
 * Private data and a shim function for implementing config_interhook_oneshot().
 */
struct oneshot_config_hook {
        struct intr_config_hook 
                        och_hook;               /* Must be first */
        ich_func_t      och_func;
        void            *och_arg;
};

static void
config_intrhook_oneshot_func(void *arg)
{
        struct oneshot_config_hook *ohook;

        ohook = arg;
        ohook->och_func(ohook->och_arg);
        config_intrhook_disestablish(&ohook->och_hook);
        free(ohook, M_DEVBUF);
}

/*
 * If we wait too long for an interrupt-driven config hook to return, print
 * a diagnostic.
 */
#define WARNING_INTERVAL_SECS   60
static void
run_interrupt_driven_config_hooks_warning(int warned)
{
        struct intr_config_hook *hook_entry;
        char namebuf[64];
        long offset;

        if (warned < 6) {
                printf("run_interrupt_driven_hooks: still waiting after %d "
                    "seconds for", warned * WARNING_INTERVAL_SECS);
                STAILQ_FOREACH(hook_entry, &intr_config_hook_list, ich_links) {
                        if (linker_search_symbol_name(
                            (caddr_t)hook_entry->ich_func, namebuf,
                            sizeof(namebuf), &offset) == 0)
                                printf(" %s", namebuf);
                        else
                                printf(" %p", hook_entry->ich_func);
                }
                printf("\n");
        }
        KASSERT(warned < 6,
            ("run_interrupt_driven_config_hooks: waited too long"));
}

static void
run_interrupt_driven_config_hooks(void)
{
        static int running;
        struct intr_config_hook *hook_entry;

        TSENTER();
        mtx_lock(&intr_config_hook_lock);

        /*
         * If hook processing is already active, any newly
         * registered hooks will eventually be notified.
         * Let the currently running session issue these
         * notifications.
         */
        if (running != 0) {
                mtx_unlock(&intr_config_hook_lock);
                return;
        }
        running = 1;

        while (next_to_notify != NULL) {
                hook_entry = next_to_notify;
                next_to_notify = STAILQ_NEXT(hook_entry, ich_links);
                hook_entry->ich_state = ICHS_RUNNING;
                mtx_unlock(&intr_config_hook_lock);
                (*hook_entry->ich_func)(hook_entry->ich_arg);
                mtx_lock(&intr_config_hook_lock);
        }

        running = 0;
        mtx_unlock(&intr_config_hook_lock);
        TSEXIT();
}

static void
boot_run_interrupt_driven_config_hooks(void *dummy)
{
        int warned;

        run_interrupt_driven_config_hooks();

        /* Block boot processing until all hooks are disestablished. */
        TSWAIT("config hooks");
        mtx_lock(&intr_config_hook_lock);
        warned = 0;
        while (!STAILQ_EMPTY(&intr_config_hook_list)) {
                if (msleep(&intr_config_hook_list, &intr_config_hook_lock,
                    0, "conifhk", WARNING_INTERVAL_SECS * hz) ==
                    EWOULDBLOCK) {
                        mtx_unlock(&intr_config_hook_lock);
                        warned++;
                        run_interrupt_driven_config_hooks_warning(warned);
                        mtx_lock(&intr_config_hook_lock);
                }
        }
        mtx_unlock(&intr_config_hook_lock);
        TSUNWAIT("config hooks");
}

SYSINIT(intr_config_hooks, SI_SUB_INT_CONFIG_HOOKS, SI_ORDER_FIRST,
        boot_run_interrupt_driven_config_hooks, NULL);

/*
 * Register a hook that will be called after "cold"
 * autoconfiguration is complete and interrupts can
 * be used to complete initialization.
 */
int
config_intrhook_establish(struct intr_config_hook *hook)
{
        struct intr_config_hook *hook_entry;

        TSHOLD("config hooks");
        mtx_lock(&intr_config_hook_lock);
        STAILQ_FOREACH(hook_entry, &intr_config_hook_list, ich_links)
                if (hook_entry == hook)
                        break;
        if (hook_entry != NULL) {
                mtx_unlock(&intr_config_hook_lock);
                printf("config_intrhook_establish: establishing an "
                       "already established hook.\n");
                return (1);
        }
        STAILQ_INSERT_TAIL(&intr_config_hook_list, hook, ich_links);
        if (next_to_notify == NULL)
                next_to_notify = hook;
        hook->ich_state = ICHS_QUEUED;
        mtx_unlock(&intr_config_hook_lock);
        if (cold == 0)
                /*
                 * XXX Call from a task since not all drivers expect
                 *     to be re-entered at the time a hook is established.
                 */
                /* XXX Sufficient for modules loaded after initial config??? */
                run_interrupt_driven_config_hooks();    
        return (0);
}

/*
 * Register a hook function that is automatically unregistered after it runs.
 */
void
config_intrhook_oneshot(ich_func_t func, void *arg)
{
        struct oneshot_config_hook *ohook;

        ohook = malloc(sizeof(*ohook), M_DEVBUF, M_WAITOK);
        ohook->och_func = func;
        ohook->och_arg  = arg;
        ohook->och_hook.ich_func = config_intrhook_oneshot_func;
        ohook->och_hook.ich_arg  = ohook;
        config_intrhook_establish(&ohook->och_hook);
}

static void
config_intrhook_disestablish_locked(struct intr_config_hook *hook)
{
        struct intr_config_hook *hook_entry;

        STAILQ_FOREACH(hook_entry, &intr_config_hook_list, ich_links)
                if (hook_entry == hook)
                        break;
        if (hook_entry == NULL)
                panic("config_intrhook_disestablish: disestablishing an "
                      "unestablished hook");

        if (next_to_notify == hook)
                next_to_notify = STAILQ_NEXT(hook, ich_links);
        STAILQ_REMOVE(&intr_config_hook_list, hook, intr_config_hook, ich_links);
        TSRELEASE("config hooks");

        /* Wakeup anyone watching the list */
        hook->ich_state = ICHS_DONE;
        wakeup(&intr_config_hook_list);
}

void
config_intrhook_disestablish(struct intr_config_hook *hook)
{
        mtx_lock(&intr_config_hook_lock);
        config_intrhook_disestablish_locked(hook);
        mtx_unlock(&intr_config_hook_lock);
}

int
config_intrhook_drain(struct intr_config_hook *hook)
{
        mtx_lock(&intr_config_hook_lock);

        /*
         * The config hook has completed, so just return.
         */
        if (hook->ich_state == ICHS_DONE) {
                mtx_unlock(&intr_config_hook_lock);
                return (ICHS_DONE);
        }

        /*
         * The config hook hasn't started running, just call disestablish.
         */
        if (hook->ich_state == ICHS_QUEUED) {
                config_intrhook_disestablish_locked(hook);
                mtx_unlock(&intr_config_hook_lock);
                return (ICHS_QUEUED);
        }

        /*
         * The config hook is running, so wait for it to complete and return.
         */
        while (hook->ich_state != ICHS_DONE) {
                if (msleep(&intr_config_hook_list, &intr_config_hook_lock,
                    0, "confhd", hz) == EWOULDBLOCK) {
                        // XXX do I whine?
                }
        }
        mtx_unlock(&intr_config_hook_lock);
        return (ICHS_RUNNING);
}

#ifdef DDB
#include <ddb/ddb.h>

DB_SHOW_COMMAND_FLAGS(conifhk, db_show_conifhk, DB_CMD_MEMSAFE)
{
        struct intr_config_hook *hook_entry;
        char namebuf[64];
        long offset;

        STAILQ_FOREACH(hook_entry, &intr_config_hook_list, ich_links) {
                if (linker_ddb_search_symbol_name(
                    (caddr_t)hook_entry->ich_func, namebuf, sizeof(namebuf),
                    &offset) == 0) {
                        db_printf("hook: %p at %s+%#lx arg: %p\n",
                            hook_entry->ich_func, namebuf, offset,
                            hook_entry->ich_arg);
                } else {
                        db_printf("hook: %p at ??+?? arg %p\n",
                            hook_entry->ich_func, hook_entry->ich_arg);
                }
        }
}
#endif /* DDB */