/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 1998, 2001 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.
 */

#include <sys/cdefs.h>
/*
 * I2C to SMB bridge
 *
 * Example:
 *
 *     smb bttv
 *       \ /
 *      smbus
 *       /  \
 *    iicsmb bti2c
 *       |
 *     iicbus
 *     /  |  \
 *  iicbb pcf ...
 *    |
 *  lpbb
 */

#include <sys/param.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/systm.h>
#include <sys/uio.h>

#include <dev/iicbus/iiconf.h>
#include <dev/iicbus/iicbus.h>

#include <dev/smbus/smb.h>
#include <dev/smbus/smbconf.h>

#include "iicbus_if.h"
#include "smbus_if.h"

struct iicsmb_softc {

#define SMB_WAITING_ADDR        0x0
#define SMB_WAITING_LOW         0x1
#define SMB_WAITING_HIGH        0x2
#define SMB_DONE                0x3
        int state;

        u_char devaddr;                 /* slave device address */

        char low;                       /* low byte received first */
        char high;                      /* high byte */

        struct mtx lock;
        device_t smbus;
};

static int iicsmb_probe(device_t);
static int iicsmb_attach(device_t);
static int iicsmb_detach(device_t);
static void iicsmb_identify(driver_t *driver, device_t parent);

static int iicsmb_intr(device_t dev, int event, char *buf);
static int iicsmb_callback(device_t dev, int index, void *data);
static int iicsmb_quick(device_t dev, u_char slave, int how);
static int iicsmb_sendb(device_t dev, u_char slave, char byte);
static int iicsmb_recvb(device_t dev, u_char slave, char *byte);
static int iicsmb_writeb(device_t dev, u_char slave, char cmd, char byte);
static int iicsmb_writew(device_t dev, u_char slave, char cmd, short word);
static int iicsmb_readb(device_t dev, u_char slave, char cmd, char *byte);
static int iicsmb_readw(device_t dev, u_char slave, char cmd, short *word);
static int iicsmb_pcall(device_t dev, u_char slave, char cmd, short sdata, short *rdata);
static int iicsmb_bwrite(device_t dev, u_char slave, char cmd, u_char count, char *buf);
static int iicsmb_bread(device_t dev, u_char slave, char cmd, u_char *count, char *buf);

static device_method_t iicsmb_methods[] = {
        /* device interface */
        DEVMETHOD(device_identify,      iicsmb_identify),
        DEVMETHOD(device_probe,         iicsmb_probe),
        DEVMETHOD(device_attach,        iicsmb_attach),
        DEVMETHOD(device_detach,        iicsmb_detach),

        /* iicbus interface */
        DEVMETHOD(iicbus_intr,          iicsmb_intr),

        /* smbus interface */
        DEVMETHOD(smbus_callback,       iicsmb_callback),
        DEVMETHOD(smbus_quick,          iicsmb_quick),
        DEVMETHOD(smbus_sendb,          iicsmb_sendb),
        DEVMETHOD(smbus_recvb,          iicsmb_recvb),
        DEVMETHOD(smbus_writeb,         iicsmb_writeb),
        DEVMETHOD(smbus_writew,         iicsmb_writew),
        DEVMETHOD(smbus_readb,          iicsmb_readb),
        DEVMETHOD(smbus_readw,          iicsmb_readw),
        DEVMETHOD(smbus_pcall,          iicsmb_pcall),
        DEVMETHOD(smbus_bwrite,         iicsmb_bwrite),
        DEVMETHOD(smbus_bread,          iicsmb_bread),

        DEVMETHOD_END
};

static driver_t iicsmb_driver = {
        "iicsmb",
        iicsmb_methods,
        sizeof(struct iicsmb_softc),
};

static void
iicsmb_identify(driver_t *driver, device_t parent)
{

        if (device_find_child(parent, "iicsmb", DEVICE_UNIT_ANY) == NULL)
                BUS_ADD_CHILD(parent, 0, "iicsmb", DEVICE_UNIT_ANY);
}

static int
iicsmb_probe(device_t dev)
{
        device_set_desc(dev, "SMBus over I2C bridge");
        return (BUS_PROBE_NOWILDCARD);
}

static int
iicsmb_attach(device_t dev)
{
        struct iicsmb_softc *sc = (struct iicsmb_softc *)device_get_softc(dev);

        mtx_init(&sc->lock, "iicsmb", NULL, MTX_DEF);

        sc->smbus = device_add_child(dev, "smbus", DEVICE_UNIT_ANY);

        /* probe and attach the smbus */
        bus_attach_children(dev);

        return (0);
}

static int
iicsmb_detach(device_t dev)
{
        struct iicsmb_softc *sc = (struct iicsmb_softc *)device_get_softc(dev);

        bus_generic_detach(dev);
        mtx_destroy(&sc->lock);

        return (0);
}

/*
 * iicsmb_intr()
 *
 * iicbus interrupt handler
 */
static int
iicsmb_intr(device_t dev, int event, char *buf)
{
        struct iicsmb_softc *sc = (struct iicsmb_softc *)device_get_softc(dev);

        mtx_lock(&sc->lock);
        switch (event) {
        case INTR_GENERAL:
        case INTR_START:
                sc->state = SMB_WAITING_ADDR;
                break;

        case INTR_STOP:
                /* call smbus intr handler */
                smbus_intr(sc->smbus, sc->devaddr,
                                sc->low, sc->high, SMB_ENOERR);
                break;

        case INTR_RECEIVE:
                switch (sc->state) {
                case SMB_DONE:
                        /* XXX too much data, discard */
                        printf("%s: too much data from 0x%x\n", __func__,
                                sc->devaddr & 0xff);
                        goto end;

                case SMB_WAITING_ADDR:
                        sc->devaddr = (u_char)*buf;
                        sc->state = SMB_WAITING_LOW;
                        break;

                case SMB_WAITING_LOW:
                        sc->low = *buf;
                        sc->state = SMB_WAITING_HIGH;
                        break;

                case SMB_WAITING_HIGH:
                        sc->high = *buf;
                        sc->state = SMB_DONE;
                        break;
                }
end:
                break;

        case INTR_TRANSMIT:
        case INTR_NOACK:
                break;

        case INTR_ERROR:
                switch (*buf) {
                case IIC_EBUSERR:
                        smbus_intr(sc->smbus, sc->devaddr, 0, 0, SMB_EBUSERR);
                        break;

                default:
                        printf("%s unknown error 0x%x!\n", __func__,
                                                                (int)*buf);
                        break;
                }
                break;

        default:
                panic("%s: unknown event (%d)!", __func__, event);
        }
        mtx_unlock(&sc->lock);

        return (0);
}

static int
iicsmb_callback(device_t dev, int index, void *data)
{
        device_t parent = device_get_parent(dev);
        int error = 0;
        int how;

        switch (index) {
        case SMB_REQUEST_BUS:
                /* request underlying iicbus */
                how = *(int *)data;
                error = iicbus_request_bus(parent, dev, how);
                break;

        case SMB_RELEASE_BUS:
                /* release underlying iicbus */
                error = iicbus_release_bus(parent, dev);
                break;

        default:
                error = EINVAL;
        }

        return (error);
}

static int
iic2smb_error(int error)
{
        switch (error) {
        case IIC_NOERR:
                return (SMB_ENOERR);
        case IIC_EBUSERR:
                return (SMB_EBUSERR);
        case IIC_ENOACK:
                return (SMB_ENOACK);
        case IIC_ETIMEOUT:
                return (SMB_ETIMEOUT);
        case IIC_EBUSBSY:
                return (SMB_EBUSY);
        case IIC_ESTATUS:
                return (SMB_EBUSERR);
        case IIC_EUNDERFLOW:
                return (SMB_EBUSERR);
        case IIC_EOVERFLOW:
                return (SMB_EBUSERR);
        case IIC_ENOTSUPP:
                return (SMB_ENOTSUPP);
        case IIC_ENOADDR:
                return (SMB_EBUSERR);
        case IIC_ERESOURCE:
                return (SMB_EBUSERR);
        default:
                return (SMB_EBUSERR);
        }
}

#define TRANSFER_MSGS(dev, msgs)        iicbus_transfer(dev, msgs, nitems(msgs))

static int
iicsmb_quick(device_t dev, u_char slave, int how)
{
        struct iic_msg msgs[] = {
             { slave, how == SMB_QWRITE ? IIC_M_WR : IIC_M_RD, 0, NULL },
        };
        int error;

        switch (how) {
        case SMB_QWRITE:
        case SMB_QREAD:
                break;
        default:
                return (SMB_EINVAL);
        }

        error = TRANSFER_MSGS(dev, msgs);
        return (iic2smb_error(error));
}

static int
iicsmb_sendb(device_t dev, u_char slave, char byte)
{
        struct iic_msg msgs[] = {
             { slave, IIC_M_WR, 1, &byte },
        };
        int error;

        error = TRANSFER_MSGS(dev, msgs);
        return (iic2smb_error(error));
}

static int
iicsmb_recvb(device_t dev, u_char slave, char *byte)
{
        struct iic_msg msgs[] = {
             { slave, IIC_M_RD, 1, byte },
        };
        int error;

        error = TRANSFER_MSGS(dev, msgs);
        return (iic2smb_error(error));
}

static int
iicsmb_writeb(device_t dev, u_char slave, char cmd, char byte)
{
        uint8_t bytes[] = { cmd, byte };
        struct iic_msg msgs[] = {
             { slave, IIC_M_WR, nitems(bytes), bytes },
        };
        int error;

        error = TRANSFER_MSGS(dev, msgs);
        return (iic2smb_error(error));
}

static int
iicsmb_writew(device_t dev, u_char slave, char cmd, short word)
{
        uint8_t bytes[] = { cmd, word & 0xff, word >> 8 };
        struct iic_msg msgs[] = {
             { slave, IIC_M_WR, nitems(bytes), bytes },
        };
        int error;

        error = TRANSFER_MSGS(dev, msgs);
        return (iic2smb_error(error));
}

static int
iicsmb_readb(device_t dev, u_char slave, char cmd, char *byte)
{
        struct iic_msg msgs[] = {
             { slave, IIC_M_WR | IIC_M_NOSTOP, 1, &cmd },
             { slave, IIC_M_RD, 1, byte },
        };
        int error;

        error = TRANSFER_MSGS(dev, msgs);
        return (iic2smb_error(error));
}

static int
iicsmb_readw(device_t dev, u_char slave, char cmd, short *word)
{
        uint8_t buf[2];
        struct iic_msg msgs[] = {
             { slave, IIC_M_WR | IIC_M_NOSTOP, 1, &cmd },
             { slave, IIC_M_RD, nitems(buf), buf },
        };
        int error;

        error = TRANSFER_MSGS(dev, msgs);
        if (error == 0)
                *word = ((uint16_t)buf[1] << 8) | buf[0];
        return (iic2smb_error(error));
}

static int
iicsmb_pcall(device_t dev, u_char slave, char cmd, short sdata, short *rdata)
{
        uint8_t in[3] = { cmd, sdata & 0xff, sdata >> 8 };
        uint8_t out[2];
        struct iic_msg msgs[] = {
             { slave, IIC_M_WR | IIC_M_NOSTOP, nitems(in), in },
             { slave, IIC_M_RD, nitems(out), out },
        };
        int error;

        error = TRANSFER_MSGS(dev, msgs);
        if (error == 0)
                *rdata = ((uint16_t)out[1] << 8) | out[0];
        return (iic2smb_error(error));
}

static int
iicsmb_bwrite(device_t dev, u_char slave, char cmd, u_char count, char *buf)
{
        uint8_t bytes[2] = { cmd, count };
        struct iic_msg msgs[] = {
             { slave, IIC_M_WR | IIC_M_NOSTOP, nitems(bytes), bytes },
             { slave, IIC_M_WR | IIC_M_NOSTART, count, buf },
        };
        int error;

        if (count > SMB_MAXBLOCKSIZE || count == 0)
                return (SMB_EINVAL);
        error = TRANSFER_MSGS(dev, msgs);
        return (iic2smb_error(error));
}

static int
iicsmb_bread(device_t dev, u_char slave, char cmd, u_char *count, char *buf)
{
        struct iic_msg msgs[] = {
             { slave, IIC_M_WR | IIC_M_NOSTOP, 1, &cmd },
             { slave, IIC_M_RD | IIC_M_NOSTOP, 1, count },
        };
        struct iic_msg block_msg[] = {
             { slave, IIC_M_RD | IIC_M_NOSTART, 0, buf },
        };
        device_t parent = device_get_parent(dev);
        int error;

        /* Have to do this because the command is split in two transfers. */
        error = iicbus_request_bus(parent, dev, IIC_WAIT | IIC_RECURSIVE);
        if (error == 0)
                error = TRANSFER_MSGS(dev, msgs);
        if (error == 0) {
                /*
                 * If the slave offers an empty or a too long reply,
                 * read one byte to generate the stop or abort.
                 */
                if (*count > SMB_MAXBLOCKSIZE || *count == 0)
                        block_msg[0].len = 1;
                else
                        block_msg[0].len = *count;
                error = TRANSFER_MSGS(dev, block_msg);
                if (*count > SMB_MAXBLOCKSIZE || *count == 0)
                        error = SMB_EINVAL;
        }
        (void)iicbus_release_bus(parent, dev);
        return (iic2smb_error(error));
}

DRIVER_MODULE(iicsmb, iicbus, iicsmb_driver, 0, 0);
DRIVER_MODULE(smbus, iicsmb, smbus_driver, 0, 0);
MODULE_DEPEND(iicsmb, iicbus, IICBUS_MINVER, IICBUS_PREFVER, IICBUS_MAXVER);
MODULE_DEPEND(iicsmb, smbus, SMBUS_MINVER, SMBUS_PREFVER, SMBUS_MAXVER);
MODULE_VERSION(iicsmb, 1);