/*-
 * Copyright (c) 2015 Justin Hibbits
 * Copyright (c) 2013 Thomas Skibo
 * 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.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/resource.h>
#include <sys/rman.h>
#include <sys/gpio.h>
#include <sys/stdarg.h>

#include <machine/bus.h>
#include <machine/resource.h>

#include <dev/fdt/fdt_common.h>
#include <dev/gpio/gpiobusvar.h>
#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>

#include "gpio_if.h"

#define MAXPIN          (7)

#define VALID_PIN(u)    ((u) >= 0 && (u) <= MAXPIN)

#define GPIO_LOCK(sc)                   mtx_lock(&(sc)->sc_mtx)
#define GPIO_UNLOCK(sc)         mtx_unlock(&(sc)->sc_mtx)
#define GPIO_LOCK_INIT(sc) \
        mtx_init(&(sc)->sc_mtx, device_get_nameunit((sc)->dev), \
            "gpio", MTX_DEF)
#define GPIO_LOCK_DESTROY(_sc)  mtx_destroy(&_sc->sc_mtx);

struct mpc85xx_gpio_softc {
        device_t        dev;
        device_t        busdev;
        struct mtx      sc_mtx;
        struct resource *out_res;       /* Memory resource */
        struct resource *in_res;
};

static device_t
mpc85xx_gpio_get_bus(device_t dev)
{
        struct mpc85xx_gpio_softc *sc;

        sc = device_get_softc(dev);

        return (sc->busdev);
}

static int
mpc85xx_gpio_pin_max(device_t dev, int *maxpin)
{

        *maxpin = MAXPIN;
        return (0);
}

/* Get a specific pin's capabilities. */
static int
mpc85xx_gpio_pin_getcaps(device_t dev, uint32_t pin, uint32_t *caps)
{

        if (!VALID_PIN(pin))
                return (EINVAL);

        *caps = (GPIO_PIN_INPUT | GPIO_PIN_OUTPUT);

        return (0);
}

/* Get a specific pin's name. */
static int
mpc85xx_gpio_pin_getname(device_t dev, uint32_t pin, char *name)
{

        if (!VALID_PIN(pin))
                return (EINVAL);

        snprintf(name, GPIOMAXNAME, "GPIO%d", pin);
        name[GPIOMAXNAME-1] = '\0';

        return (0);
}

/* Set a specific output pin's value. */
static int
mpc85xx_gpio_pin_set(device_t dev, uint32_t pin, unsigned int value)
{
        struct mpc85xx_gpio_softc *sc = device_get_softc(dev);
        uint32_t outvals;
        uint8_t pinbit;

        if (!VALID_PIN(pin) || value > 1)
                return (EINVAL);

        GPIO_LOCK(sc);
        pinbit = 31 - pin;

        outvals = bus_read_4(sc->out_res, 0);
        outvals &= ~(1 << pinbit);
        outvals |= (value << pinbit);
        bus_write_4(sc->out_res, 0, outvals);

        GPIO_UNLOCK(sc);

        return (0);
}

/* Get a specific pin's input value. */
static int
mpc85xx_gpio_pin_get(device_t dev, uint32_t pin, unsigned int *value)
{
        struct mpc85xx_gpio_softc *sc = device_get_softc(dev);

        if (!VALID_PIN(pin))
                return (EINVAL);

        *value = (bus_read_4(sc->in_res, 0) >> (31 - pin)) & 1;

        return (0);
}

/* Toggle a pin's output value. */
static int
mpc85xx_gpio_pin_toggle(device_t dev, uint32_t pin)
{
        struct mpc85xx_gpio_softc *sc = device_get_softc(dev);
        uint32_t val;

        if (!VALID_PIN(pin))
                return (EINVAL);

        GPIO_LOCK(sc);

        val = bus_read_4(sc->out_res, 0);
        val ^= (1 << (31 - pin));
        bus_write_4(sc->out_res, 0, val);

        GPIO_UNLOCK(sc);

        return (0);
}

static int
mpc85xx_gpio_probe(device_t dev)
{
        uint32_t svr;

        if (!ofw_bus_status_okay(dev))
                return (ENXIO);

        if (!ofw_bus_is_compatible(dev, "gpio"))
                return (ENXIO);

        svr = mfspr(SPR_SVR);
        switch (SVR_VER(svr)) {
        case SVR_MPC8533:
        case SVR_MPC8533E:
                break;
        default:
                return (ENXIO);
        }

        device_set_desc(dev, "MPC85xx GPIO driver");
        return (0);
}

static int mpc85xx_gpio_detach(device_t dev);

static int
mpc85xx_gpio_attach(device_t dev)
{
        struct mpc85xx_gpio_softc *sc = device_get_softc(dev);
        int rid;

        sc->dev = dev;

        GPIO_LOCK_INIT(sc);

        /* Allocate memory. */
        rid = 0;
        sc->out_res = bus_alloc_resource_any(dev,
                     SYS_RES_MEMORY, &rid, RF_ACTIVE);
        if (sc->out_res == NULL) {
                device_printf(dev, "Can't allocate memory for device output port");
                mpc85xx_gpio_detach(dev);
                return (ENOMEM);
        }

        rid = 1;
        sc->in_res = bus_alloc_resource_any(dev,
                     SYS_RES_MEMORY, &rid, RF_ACTIVE);
        if (sc->in_res == NULL) {
                device_printf(dev, "Can't allocate memory for device input port");
                mpc85xx_gpio_detach(dev);
                return (ENOMEM);
        }

        OF_device_register_xref(OF_xref_from_node(ofw_bus_get_node(dev)), dev);

        sc->busdev = gpiobus_add_bus(dev);
        if (sc->busdev == NULL) {
                mpc85xx_gpio_detach(dev);
                return (ENOMEM);
        }

        bus_attach_children(dev);
        return (0);
}

static int
mpc85xx_gpio_detach(device_t dev)
{
        struct mpc85xx_gpio_softc *sc = device_get_softc(dev);

        gpiobus_detach_bus(dev);

        if (sc->out_res != NULL) {
                /* Release output port resource. */
                bus_release_resource(dev, SYS_RES_MEMORY,
                                     rman_get_rid(sc->out_res), sc->out_res);
        }

        if (sc->in_res != NULL) {
                /* Release input port resource. */
                bus_release_resource(dev, SYS_RES_MEMORY,
                                     rman_get_rid(sc->in_res), sc->in_res);
        }

        GPIO_LOCK_DESTROY(sc);

        return (0);
}

static device_method_t mpc85xx_gpio_methods[] = {
        /* device_if */
        DEVMETHOD(device_probe,         mpc85xx_gpio_probe),
        DEVMETHOD(device_attach,        mpc85xx_gpio_attach),
        DEVMETHOD(device_detach,        mpc85xx_gpio_detach),

        /* GPIO protocol */
        DEVMETHOD(gpio_get_bus,         mpc85xx_gpio_get_bus),
        DEVMETHOD(gpio_pin_max,         mpc85xx_gpio_pin_max),
        DEVMETHOD(gpio_pin_getname,     mpc85xx_gpio_pin_getname),
        DEVMETHOD(gpio_pin_getcaps,     mpc85xx_gpio_pin_getcaps),
        DEVMETHOD(gpio_pin_get,         mpc85xx_gpio_pin_get),
        DEVMETHOD(gpio_pin_set,         mpc85xx_gpio_pin_set),
        DEVMETHOD(gpio_pin_toggle,      mpc85xx_gpio_pin_toggle),

        DEVMETHOD_END
};

static driver_t mpc85xx_gpio_driver = {
        "gpio",
        mpc85xx_gpio_methods,
        sizeof(struct mpc85xx_gpio_softc),
};

EARLY_DRIVER_MODULE(mpc85xx_gpio, simplebus, mpc85xx_gpio_driver, NULL, NULL,
    BUS_PASS_RESOURCE + BUS_PASS_ORDER_MIDDLE);