/*-
 * Copyright (c) 1998 Nicolas Souchu
 * 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.
 *
 * $FreeBSD: src/sys/dev/iicbus/iiconf.c,v 1.19 2008/08/23 07:38:00 imp Exp $
 * $DragonFly: src/sys/bus/iicbus/iiconf.c,v 1.5 2005/06/02 20:40:36 dillon Exp $
 *
 */
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/bus.h>
#include <sys/thread2.h>

#include <bus/iicbus/iiconf.h>
#include <bus/iicbus/iicbus.h>
#include "iicbus_if.h"

/*
 * iicbus_intr()
 */
void
iicbus_intr(device_t bus, int event, char *buf)
{
        struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);

        /* call owner's intr routine */
        if (sc->owner)
                IICBUS_INTR(sc->owner, event, buf);

        return;
}

static int
iicbus_poll(struct iicbus_softc *sc, int how)
{
        int error;

        switch (how) {
        case IIC_WAIT | IIC_INTR:
                error = tsleep(sc, PCATCH, "iicreq", 0);
                break;

        case IIC_WAIT | IIC_NOINTR:
                error = tsleep(sc, 0, "iicreq", 0);
                break;

        default:
                return (EWOULDBLOCK);
                break;
        }

        return (error);
}

/*
 * iicbus_request_bus()
 *
 * Allocate the device to perform transfers.
 *
 * how  : IIC_WAIT or IIC_DONTWAIT
 */
int
iicbus_request_bus(device_t bus, device_t dev, int how)
{
        struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
        int error = 0;

        /* first, ask the underlying layers if the request is ok */
        do {
                error = IICBUS_CALLBACK(device_get_parent(bus),
                                                IIC_REQUEST_BUS, (caddr_t)&how);
                if (error)
                        error = iicbus_poll(sc, how);
        } while (error == EWOULDBLOCK);

        while (!error) {
                crit_enter();
                if (sc->owner && sc->owner != dev) {
                        crit_exit();
                        error = iicbus_poll(sc, how);
                } else {
                        sc->owner = dev;
                        crit_exit();
                        return (0);
                }

                /* free any allocated resource */
                if (error)
                        IICBUS_CALLBACK(device_get_parent(bus), IIC_RELEASE_BUS,
                                        (caddr_t)&how);
        }

        return (error);
}

/*
 * iicbus_release_bus()
 *
 * Release the device allocated with iicbus_request_dev()
 */
int
iicbus_release_bus(device_t bus, device_t dev)
{
        struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
        int error;

        /* first, ask the underlying layers if the release is ok */
        error = IICBUS_CALLBACK(device_get_parent(bus), IIC_RELEASE_BUS, NULL);

        if (error)
                return (error);

        crit_enter();
        if (sc->owner != dev) {
                crit_exit();
                return (EACCES);
        }
        sc->owner = NULL;
        crit_exit();

        /* wakeup waiting processes */
        wakeup(sc);

        return (0);
}

/*
 * iicbus_started()
 *
 * Test if the iicbus is started by the controller
 */
int
iicbus_started(device_t bus)
{
        struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);

        return (sc->started);
}

/*
 * iicbus_start()
 *
 * Send start condition to the slave addressed by 'slave'
 */
int
iicbus_start(device_t bus, u_char slave, int timeout)
{
        struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
        int error = 0;

        if (sc->started)
                return (EINVAL);                /* bus already started */

        if (!(error = IICBUS_START(device_get_parent(bus), slave, timeout)))
                sc->started = slave;
        else
                sc->started = 0;

        return (error);
}

/*
 * iicbus_repeated_start()
 *
 * Send start condition to the slave addressed by 'slave'
 */
int
iicbus_repeated_start(device_t bus, u_char slave, int timeout)
{
        struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
        int error = 0;

        if (!sc->started)
                return (EINVAL);     /* bus should have been already started */

        if (!(error = IICBUS_REPEATED_START(device_get_parent(bus), slave, timeout)))
                sc->started = slave;
        else
                sc->started = 0;

        return (error);
}

/*
 * iicbus_stop()
 *
 * Send stop condition to the bus
 */
int
iicbus_stop(device_t bus)
{
        struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
        int error = 0;

        if (!sc->started)
                return (EINVAL);                /* bus not started */

        error = IICBUS_STOP(device_get_parent(bus));

        /* refuse any further access */
        sc->started = 0;

        return (error);
}

/*
 * iicbus_write()
 *
 * Write a block of data to the slave previously started by
 * iicbus_start() call
 */
int
iicbus_write(device_t bus, const char *buf, int len, int *sent, int timeout)
{
        struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
        
        /* a slave must have been started with the appropriate address */
        if (!sc->started || (sc->started & LSB))
                return (EINVAL);

        return (IICBUS_WRITE(device_get_parent(bus), buf, len, sent, timeout));
}

/*
 * iicbus_read()
 *
 * Read a block of data from the slave previously started by
 * iicbus_read() call
 */
int 
iicbus_read(device_t bus, char *buf, int len, int *read, int last, int delay)
{
        struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
        
        /* a slave must have been started with the appropriate address */
        if (!sc->started || !(sc->started & LSB))
                return (EINVAL);

        return (IICBUS_READ(device_get_parent(bus), buf, len, read, last, delay));
}

/*
 * iicbus_write_byte()
 *
 * Write a byte to the slave previously started by iicbus_start() call
 */
int
iicbus_write_byte(device_t bus, char byte, int timeout)
{
        char data = byte;
        int sent;

        return (iicbus_write(bus, &data, 1, &sent, timeout));
}

/*
 * iicbus_read_byte()
 *
 * Read a byte from the slave previously started by iicbus_start() call
 */
int
iicbus_read_byte(device_t bus, char *byte, int timeout)
{
        int read;

        return (iicbus_read(bus, byte, 1, &read, IIC_LAST_READ, timeout));
}

/*
 * iicbus_block_write()
 *
 * Write a block of data to slave ; start/stop protocol managed
 */
int
iicbus_block_write(device_t bus, u_char slave, char *buf, int len, int *sent)
{
        u_char addr = slave & ~LSB;
        int error;

        if ((error = iicbus_start(bus, addr, 0)))
                return (error);

        error = iicbus_write(bus, buf, len, sent, 0);

        iicbus_stop(bus);

        return (error);
}

/*
 * iicbus_block_read()
 *
 * Read a block of data from slave ; start/stop protocol managed
 */
int
iicbus_block_read(device_t bus, u_char slave, char *buf, int len, int *read)
{
        u_char addr = slave | LSB;
        int error;

        if ((error = iicbus_start(bus, addr, 0)))
                return (error);

        error = iicbus_read(bus, buf, len, read, IIC_LAST_READ, 0);

        iicbus_stop(bus);

        return (error);
}

/*
 * iicbus_transfer()
 *
 * Do an aribtrary number of transfers on the iicbus.  We pass these
 * raw requests to the bridge driver.  If the bridge driver supports
 * them directly, then it manages all the details.  If not, it can use
 * the helper function iicbus_transfer_gen() which will do the
 * transfers at a low level.
 *
 * Pointers passed in as part of iic_msg must be kernel pointers.
 * Callers that have user addresses to manage must do so on their own.
 */
int
iicbus_transfer(device_t bus, struct iic_msg *msgs, uint32_t nmsgs)
{
        return (IICBUS_TRANSFER(device_get_parent(bus), msgs, nmsgs));
}

/*
 * Generic version of iicbus_transfer that calls the appropriate
 * routines to accomplish this.  See note above about acceptable
 * buffer addresses.
 */
int
iicbus_transfer_gen(device_t dev, struct iic_msg *msgs, uint32_t nmsgs)
{
        int i, error, lenread, lenwrote, nkid;
        device_t *children, bus;

        if ((error = device_get_children(dev, &children, &nkid)) != 0)
                return (error);
        if (nkid != 1) {
                kfree(children, M_TEMP);
                return (EIO);
        }
        bus = children[0];
        kfree(children, M_TEMP);
        for (i = 0, error = 0; i < nmsgs && error == 0; i++) {
                if (msgs[i].flags & IIC_M_RD)
                        error = iicbus_block_read(bus, msgs[i].slave,
                            msgs[i].buf, msgs[i].len, &lenread);
                else
                        error = iicbus_block_write(bus, msgs[i].slave,
                            msgs[i].buf, msgs[i].len, &lenwrote);
        }
        return (error);
}