/*-
 * Copyright (c) 1997 Doug Rabson
 * All rights reserved.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
 *
 *	$Id$
 */

#include <sys/param.h>
#include <sys/queue.h>
#include <sys/malloc.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/bus_private.h>
#include <sys/systm.h>

device_t
bus_get_device(bus_t bus)
{
    return bus->dev;
}

void
bus_print_device(bus_t bus, device_t dev)
{
    printf("%s%d", device_get_name(dev), device_get_unit(dev));
    if (device_is_alive(dev)) {
	if (device_get_desc(dev))
	    printf(": <%s>", device_get_desc(dev));
	bus->ops->print_device(bus, dev);
    } else
	printf(" not found");
    printf("\n");
}

int
bus_read_ivar(bus_t bus, device_t dev,
	      int index, u_long *result)
{
    return bus->ops->read_ivar(bus, dev, index, result);
}

int
bus_write_ivar(bus_t bus, device_t dev,
	       int index, u_long value)
{
    return bus->ops->write_ivar(bus, dev, index, value);
}

int
bus_map_intr(bus_t bus, device_t dev, driver_intr_t *intr, void *arg)
{
    return bus->ops->map_intr(bus, dev, intr, arg);
}

static devclass_list_t devclasses;

static void
devclass_init(void)
{
    TAILQ_INIT(&devclasses);
}

static devclass_t
devclass_find_internal(const char *classname, int create)
{
    devclass_t dc;

    for (dc = TAILQ_FIRST(&devclasses); dc; dc = TAILQ_NEXT(dc, link))
	if (!strcmp(dc->name, classname))
	    return dc;

    if (create) {
	dc = malloc(sizeof(struct devclass) + strlen(classname) + 1,
		    M_DEVBUF, M_NOWAIT);
	if (!dc)
	    return NULL;
	dc->name = (char*) (dc + 1);
	strcpy(dc->name, classname);
	dc->devices = NULL;
	dc->maxunit = 0;
	dc->nextunit = 0;
	TAILQ_INIT(&dc->drivers);
	TAILQ_INSERT_TAIL(&devclasses, dc, link);
    }

    return dc;
}

devclass_t
devclass_find(const char *classname)
{
    return devclass_find_internal(classname, FALSE);
}

int
devclass_add_driver(devclass_t dc, driver_t *driver)
{
    /*
     * Make sure the devclass which the driver is implementing exists.
     */
    devclass_find_internal(driver->name, TRUE);

    TAILQ_INSERT_TAIL(&dc->drivers, driver, link);

    return 0;
}

int
devclass_delete_driver(devclass_t dc, driver_t *driver)
{
    bus_t bus;
    device_t dev;
    int i;
    int error;

    /*
     * Disassociate from any devices.  We iterate through all the
     * devices attached to any bus in this class.
     */
    for (i = 0; i < dc->maxunit; i++) {
	if (dc->devices[i]) {
	    bus = dc->devices[i]->softc;
	    for (dev = TAILQ_FIRST(&bus->devices); dev;
		 dev = TAILQ_NEXT(dev, link))
		if (dev->driver == driver) {
		    if (error = device_detach(dev))
			return error;
		    device_set_driver(dev, NULL);
		}
	}
    }

    TAILQ_REMOVE(&dc->drivers, driver, link);
    return 0;
}

driver_t *
devclass_find_driver(devclass_t dc, const char *classname)
{
    driver_t *driver;

    for (driver = TAILQ_FIRST(&dc->drivers); driver;
	 driver = TAILQ_NEXT(driver, link))
	if (!strcmp(driver->name, classname))
	    return driver;

    return NULL;
}

const char *
devclass_get_name(devclass_t dc)
{
    return dc->name;
}

device_t
devclass_get_device(devclass_t dc, int unit)
{
    if (unit < 0 || unit >= dc->maxunit)
	return NULL;
    return dc->devices[unit];
}

void *
devclass_get_softc(devclass_t dc, int unit)
{
    device_t dev;

    if (unit < 0 || unit >= dc->maxunit)
	return NULL;
    dev = dc->devices[unit];
    if (!dev || dev->state < DS_ATTACHED)
	return NULL;
    return dev->softc;
}

int
devclass_get_devices(devclass_t dc, device_t **devlistp, int *devcountp)
{
    int i;
    int count;
    device_t dev;
    device_t *list;
    
    count = 0;
    for (i = 0; i < dc->maxunit; i++)
	if (dc->devices[i])
	    count++;

    list = malloc(count * sizeof(device_t), M_TEMP, M_NOWAIT);
    if (!list)
	return ENOMEM;

    count = 0;
    for (i = 0; i < dc->maxunit; i++)
	if (dc->devices[i]) {
	    list[count] = dc->devices[i];
	    count++;
	}

    *devlistp = list;
    *devcountp = count;

    return 0;
}

int
devclass_get_maxunit(devclass_t dc)
{
    return dc->maxunit;
}

static int
devclass_alloc_unit(devclass_t dc, int *unitp)
{
    int unit = *unitp;

    /*
     * If we have been given a wired unit number, check for existing
     * device.
     */
    if (unit != -1) {
	device_t dev;
	dev = devclass_get_device(dc, unit);
	if (dev) {
	    printf("devclass_alloc_unit: %s%d already exists, using next available unit number\n", dc->name, unit);
	    unit = -1;
	}
    }

    if (unit == -1) {
	unit = dc->nextunit;
	dc->nextunit++;
    } else if (dc->nextunit <= unit)
	dc->nextunit = unit + 1;

    if (unit >= dc->maxunit) {
	device_t *newlist;
	int newsize;

	newsize = (dc->maxunit ? 2 * dc->maxunit
		   : MINALLOCSIZE / sizeof(device_t));
	newlist = malloc(sizeof(device_t) * newsize, M_DEVBUF, M_NOWAIT);
	if (!newlist)
	    return ENOMEM;
	bcopy(dc->devices, newlist, sizeof(device_t) * dc->maxunit);
	bzero(newlist + dc->maxunit,
	      sizeof(device_t) * (newsize - dc->maxunit));
	if (dc->devices)
	    free(dc->devices, M_DEVBUF);
	dc->devices = newlist;
	dc->maxunit = newsize;
    }

    *unitp = unit;
    return 0;
}

static int
devclass_add_device(devclass_t dc, device_t dev)
{
    int error;

    if (error = devclass_alloc_unit(dc, &dev->unit))
	return error;
    dc->devices[dev->unit] = dev;
    dev->devclass = dc;
    return 0;
}

static int
devclass_delete_device(devclass_t dc, device_t dev)
{
    if (dev->devclass != dc
	|| dc->devices[dev->unit] != dev)
	panic("devclass_delete_device: inconsistent device class");
    dc->devices[dev->unit] = NULL;
    if (dev->flags & DF_WILDCARD)
	dev->unit = -1;
    dev->devclass = NULL;
    while (dc->nextunit > 0 && dc->devices[dc->nextunit - 1] == NULL)
	dc->nextunit--;
    return 0;
}

static device_t
make_device(bus_t bus, const char *name,
	    int unit, void *ivars)
{
    driver_t *driver;
    device_t dev;
    devclass_t dc;
    int error;

    if (name) {
	dc = devclass_find_internal(name, TRUE);
	if (!dc) {
	    printf("make_device: can't find device class %s\n", name);
	    return NULL;
	}

	if (error = devclass_alloc_unit(dc, &unit))
	    return NULL;
    } else
	dc = NULL;

    dev = malloc(sizeof(struct device), M_DEVBUF, M_NOWAIT);
    if (!dev)
	return 0;

    dev->parent = bus;
    dev->driver = NULL;
    dev->devclass = dc;
    dev->unit = unit;
    dev->desc = NULL;
    dev->busy = 0;
    dev->flags = DF_ENABLED;
    if (unit == -1)
	dev->flags |= DF_WILDCARD;
    if (name)
	dev->flags |= DF_FIXEDCLASS;
    dev->ivars = ivars;
    dev->softc = NULL;

    if (dc)
	dc->devices[unit] = dev;

    dev->state = DS_NOTPRESENT;

    return dev;
}

void
bus_init(bus_t bus, device_t dev, bus_ops_t *ops)
{
	bus->ops = ops;
	bus->dev = dev;
	TAILQ_INIT(&bus->devices);
}

device_t
bus_add_device(bus_t bus, const char *name, int unit, void *ivars)
{
    device_t dev;

    dev = make_device(bus, name, unit, ivars);

    TAILQ_INSERT_TAIL(&bus->devices, dev, link);

    return dev;
}

device_t
bus_add_device_after(bus_t bus, device_t place, const char *name,
		     int unit, void *ivars)
{
    device_t dev;

    dev = make_device(bus, name, unit, ivars);

    if (place) {
	TAILQ_INSERT_AFTER(&bus->devices, place, dev, link);
    } else {
	TAILQ_INSERT_HEAD(&bus->devices, dev, link);
    }

    return dev;
}

int
bus_delete_device(bus_t bus, device_t dev)
{
    int error;

    if (error = device_detach(dev))
	return error;
    if (dev->devclass)
	devclass_delete_device(dev->devclass, dev);
    TAILQ_REMOVE(&bus->devices, dev, link);
    free(dev, M_DEVBUF);

    return 0;
}

/*
 * Find only devices attached to this bus.
 */
device_t
bus_find_device(bus_t bus, const char *classname, int unit)
{
    devclass_t dc;
    device_t dev;

    dc = devclass_find(classname);
    if (!dc)
	return NULL;

    dev = devclass_get_device(dc, unit);
    if (dev && dev->parent == bus)
	return dev;
    return NULL;
}

static driver_t *
first_matching_driver(devclass_t dc, device_t dev)
{
    if (dev->devclass)
	return devclass_find_driver(dc, dev->devclass->name);
    else
	return TAILQ_FIRST(&dc->drivers);
}

static driver_t *
next_matching_driver(devclass_t dc, device_t dev, driver_t *last)
{
    if (dev->devclass) {
	driver_t *driver;
	for (driver = TAILQ_NEXT(last, link); driver;
	     driver = TAILQ_NEXT(driver, link))
	    if (!strcmp(dev->devclass->name, driver->name))
		return driver;
	return NULL;
    } else
	return TAILQ_NEXT(last, link);
}

static int
bus_probe_device(bus_t bus, device_t dev)
{
    devclass_t dc;
    driver_t *driver;
    void *softc;

    dc = bus->dev->devclass;
    if (dc == NULL)
	panic("bus_probe_device: bus' device has no devclass");

    if (dev->state == DS_ALIVE)
	return 0;

    for (driver = first_matching_driver(dc, dev);
	 driver;
	 driver = next_matching_driver(dc, dev, driver)) {
	device_set_driver(dev, driver);
	if (driver->probe(bus, dev) == 0) {
	    if (!dev->devclass)
		device_set_devclass(dev, driver->name);
	    dev->state = DS_ALIVE;
	    return 0;
	}
    }

    return ENXIO;
}

int
bus_generic_attach(bus_t parent, device_t busdev)
{
    bus_t bus = busdev->softc;
    device_t dev;
    int error;

    for (dev = TAILQ_FIRST(&bus->devices);
	 dev; dev = TAILQ_NEXT(dev, link))
	device_probe_and_attach(dev);

    return 0;
}

int
bus_generic_detach(bus_t parent, device_t busdev)
{
    bus_t bus = busdev->softc;
    device_t dev;
    int error;

    if (busdev->state != DS_ATTACHED)
	return EBUSY;

    for (dev = TAILQ_FIRST(&bus->devices);
	 dev; dev = TAILQ_NEXT(dev, link))
	device_detach(dev);

    return 0;
}

int
bus_generic_shutdown(bus_t parent, device_t busdev)
{
    bus_t bus = busdev->softc;
    device_t dev;

    for (dev = TAILQ_FIRST(&bus->devices);
	 dev; dev = TAILQ_NEXT(dev, link))
	device_shutdown(dev);

    return 0;
}

bus_t
device_get_parent(device_t dev)
{
    return dev->parent;
}

driver_t *
device_get_driver(device_t dev)
{
    return dev->driver;
}

devclass_t
device_get_devclass(device_t dev)
{
    return dev->devclass;
}

const char *
device_get_name(device_t dev)
{
    if (dev->devclass)
	return devclass_get_name(dev->devclass);
    return NULL;
}

int
device_get_unit(device_t dev)
{
    return dev->unit;
}

const char *
device_get_desc(device_t dev)
{
    return dev->desc;
}

void
device_set_desc(device_t dev, const char* desc)
{
    dev->desc = desc;
}

void *
device_get_softc(device_t dev)
{
    return dev->softc;
}

void *
device_get_ivars(device_t dev)
{
    return dev->ivars;
}

device_state_t
device_get_state(device_t dev)
{
    return dev->state;
}

void
device_enable(device_t dev)
{
    dev->flags |= DF_ENABLED;
}

void
device_disable(device_t dev)
{
    dev->flags &= ~DF_ENABLED;
}

void
device_busy(device_t dev)
{
    if (dev->state < DS_ATTACHED)
	panic("device_busy: called for unattached device");
    if (dev->busy == 0 && dev->parent)
	device_busy(dev->parent->dev);
    dev->busy++;
    dev->state = DS_BUSY;
}

void
device_unbusy(device_t dev)
{
    if (dev->state != DS_BUSY)
	panic("device_unbusy: called for non-busy device");
    dev->busy--;
    if (dev->busy == 0) {
	if (dev->parent->dev)
	    device_unbusy(dev->parent->dev);
	dev->state = DS_ATTACHED;
    }
}

int
device_is_enabled(device_t dev)
{
    return (dev->flags & DF_ENABLED) != 0;
}

int
device_is_alive(device_t dev)
{
    return dev->state >= DS_ALIVE;
}

int
device_set_devclass(device_t dev, const char *classname)
{
    devclass_t dc;

    if (dev->devclass) {
	printf("device_set_devclass: device class already set\n");
	return EINVAL;
    }

    dc = devclass_find_internal(classname, TRUE);
    if (!dc)
	return ENOMEM;

    return devclass_add_device(dc, dev);
}

int
device_set_driver(device_t dev, driver_t *driver)
{
    if (dev->state >= DS_ATTACHED)
	return EBUSY;

    if (dev->driver == driver)
	return 0;

    if (dev->softc) {
	free(dev->softc, M_DEVBUF);
	dev->softc = NULL;
    }
    dev->driver = driver;
    if (driver) {
	dev->softc = malloc(driver->softc, M_DEVBUF, M_NOWAIT);
	bzero(dev->softc, driver->softc);
    }
    return 0;
}

int
device_probe_and_attach(device_t dev)
{
    bus_t bus = dev->parent;
    int error;

    if (dev->state >= DS_ALIVE)
	return 0;

    if (dev->flags & DF_ENABLED) {
	bus_probe_device(bus, dev);
	bus_print_device(bus, dev);
	if (dev->state == DS_ALIVE) {
	    error = dev->driver->attach(bus, dev);
	    if (!error)
		dev->state = DS_ATTACHED;
	    else {
		printf("device_probe_and_attach: %s%n attach returned %d\n",
		       dev->driver->name, dev->unit, error);
		device_set_driver(dev, NULL);
		dev->state = DS_NOTPRESENT;
	    }
	}
    } else
	printf("%s%d: disabled, not probed.\n",
	       dev->devclass->name, dev->unit);

    return 0;
}

int
device_detach(device_t dev)
{
    int error;

    if (dev->state == DS_BUSY)
	return EBUSY;
    if (dev->state != DS_ATTACHED)
	return 0;

    if (dev->driver->detach) {
	if (error = dev->driver->detach(dev->parent, dev))
	    return error;
    } else
	return EBUSY;

    if (!(dev->flags & DF_FIXEDCLASS))
	devclass_delete_device(dev->devclass, dev);

    dev->state = DS_NOTPRESENT;
    device_set_driver(dev, NULL);

    return 0;
}

int
device_shutdown(device_t dev)
{
    if (dev->state < DS_ATTACHED)
	return 0;
    if (dev->driver->shutdown)
	return dev->driver->shutdown(dev->parent, dev);
    else
	return 0;
}

void
null_print_device(bus_t bus, device_t dev)
{
}

int
null_read_ivar(bus_t bus, device_t dev, int index, u_long* result)
{
    return ENOENT;
}

int
null_write_ivar(bus_t bus, device_t dev, int index, u_long value)
{
    return ENOENT;
}

int
null_map_intr(bus_t bus, device_t dev, driver_intr_t *intr, void *arg)
{
    /* Propagate up the bus hierarchy until someone handles it. */
    if (bus->dev)
	return bus_map_intr(bus->dev->parent, bus->dev, intr, arg);
    else
	return EINVAL;
}

bus_ops_t null_bus_ops = {
    null_print_device,
    null_read_ivar,
    null_write_ivar,
    null_map_intr,
};

static void
root_bus_print_device(bus_t bus, device_t dev)
{
}

static int root_bus_map_intr(bus_t bus, device_t dev,
			     driver_intr_t *intr, void *arg)
{
    return EINVAL;
}

static bus_ops_t root_bus_ops = {
    root_bus_print_device,
    null_read_ivar,
    null_write_ivar,
    root_bus_map_intr,
};

static struct bus the_root_bus;
bus_t root_bus = &the_root_bus;
device_t root_device;
devclass_t root_devclass;

static int
root_bus_module_handler(module_t mod, modeventtype_t what, void* arg)
{
    switch (what) {
    case MOD_LOAD:
	devclass_init();
	root_device = make_device(NULL, "root", 0, NULL);
	root_device->state = DS_ATTACHED;
	bus_init(root_bus, root_device, &root_bus_ops);
	root_devclass = devclass_find("root");
	return 0;
    }

    return 0;
}

static moduledata_t root_bus_mod = {
	"rootbus",
	root_bus_module_handler,
	0
};
DECLARE_MODULE(rootbus, root_bus_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST);

void
root_bus_configure()
{
    device_t dev;
    int error;

    for (dev = TAILQ_FIRST(&root_bus->devices); dev;
	 dev = TAILQ_NEXT(dev, link)) {
	device_probe_and_attach(dev);
    }
}

int
driver_module_handler(module_t mod, modeventtype_t what, void* arg)
{
    struct driver_module_data* data = (struct driver_module_data*) arg;
    devclass_t bus_devclass = devclass_find_internal(data->busname, TRUE);
    int error;

    switch (what) {
    case MOD_LOAD:
	if (error = devclass_add_driver(bus_devclass,
					data->driver))
	    return error;
	*data->devclass =
	    devclass_find_internal(data->driver->name, TRUE);
	break;

    case MOD_UNLOAD:
	if (error = devclass_delete_driver(bus_devclass,
					   data->driver))
	    return error;
	break;
    }

    if (data->chainevh)
	return data->chainevh(mod, what, data->chainarg);
    else
	return 0;
}