/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 1998, 2001 Nicolas Souchu
 * Copyright (c) 2023 Juniper Networks, Inc.
 * 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/abi_compat.h>
#include <sys/bus.h>
#include <sys/conf.h>
#include <sys/fcntl.h>
#include <sys/lock.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/sx.h>
#include <sys/systm.h>
#include <sys/uio.h>
#include <sys/errno.h>

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

#include "iicbus_if.h"

struct iic_softc {
        device_t sc_dev;
        struct cdev *sc_devnode;
};

struct iic_cdevpriv {
        struct sx lock;
        struct iic_softc *sc;
        bool started;
        uint8_t addr;
};

#ifdef COMPAT_FREEBSD32
struct iic_msg32 {
        uint16_t slave;
        uint16_t flags;
        uint16_t len;
        uint32_t buf;
};

struct iiccmd32 {
        u_char slave;
        uint32_t count;
        uint32_t last;
        uint32_t buf;
};

struct iic_rdwr_data32 {
        uint32_t msgs;
        uint32_t nmsgs;
};

#define I2CWRITE32      _IOW('i', 4, struct iiccmd32)
#define I2CREAD32       _IOW('i', 5, struct iiccmd32)
#define I2CRDWR32       _IOW('i', 6, struct iic_rdwr_data32)
#endif

#define IIC_LOCK(cdp)                   sx_xlock(&(cdp)->lock)
#define IIC_UNLOCK(cdp)                 sx_xunlock(&(cdp)->lock)

static MALLOC_DEFINE(M_IIC, "iic", "I2C device data");

static int iic_probe(device_t);
static int iic_attach(device_t);
static int iic_detach(device_t);
static void iic_identify(driver_t *driver, device_t parent);
static void iicdtor(void *data);
static int iicuio_move(struct iic_cdevpriv *priv, struct uio *uio, int last);
static int iicuio(struct cdev *dev, struct uio *uio, int ioflag);
static int iicrdwr(struct iic_cdevpriv *priv, struct iic_rdwr_data *d, int flags, bool compat32);

static device_method_t iic_methods[] = {
        /* device interface */
        DEVMETHOD(device_identify,      iic_identify),
        DEVMETHOD(device_probe,         iic_probe),
        DEVMETHOD(device_attach,        iic_attach),
        DEVMETHOD(device_detach,        iic_detach),

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

        DEVMETHOD_END
};

static driver_t iic_driver = {
        "iic",
        iic_methods,
        sizeof(struct iic_softc),
};

static  d_open_t        iicopen;
static  d_ioctl_t       iicioctl;

static struct cdevsw iic_cdevsw = {
        .d_version =    D_VERSION,
        .d_open =       iicopen,
        .d_read =       iicuio,
        .d_write =      iicuio,
        .d_ioctl =      iicioctl,
        .d_name =       "iic",
};

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

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

static int
iic_probe(device_t dev)
{
        if (iicbus_get_addr(dev) > 0)
                return (ENXIO);

        device_set_desc(dev, "I2C generic I/O");

        return (0);
}
        
static int
iic_attach(device_t dev)
{
        struct iic_softc *sc;

        sc = device_get_softc(dev);
        sc->sc_dev = dev;
        sc->sc_devnode = make_dev(&iic_cdevsw, device_get_unit(dev),
                        UID_ROOT, GID_WHEEL,
                        0600, "iic%d", device_get_unit(dev));
        if (sc->sc_devnode == NULL) {
                device_printf(dev, "failed to create character device\n");
                return (ENXIO);
        }
        sc->sc_devnode->si_drv1 = sc;

        return (0);
}

static int
iic_detach(device_t dev)
{
        struct iic_softc *sc;

        sc = device_get_softc(dev);

        if (sc->sc_devnode)
                destroy_dev(sc->sc_devnode);

        return (0);
}

static int
iicopen(struct cdev *dev, int flags, int fmt, struct thread *td)
{
        struct iic_cdevpriv *priv;
        int error;

        priv = malloc(sizeof(*priv), M_IIC, M_WAITOK | M_ZERO);

        sx_init(&priv->lock, "iic");
        priv->sc = dev->si_drv1;

        error = devfs_set_cdevpriv(priv, iicdtor); 
        if (error != 0)
                free(priv, M_IIC);

        return (error);
}

static void
iicdtor(void *data)
{
        device_t iicdev, parent;
        struct iic_cdevpriv *priv;

        priv = data;
        KASSERT(priv != NULL, ("iic cdevpriv should not be NULL!"));

        iicdev = priv->sc->sc_dev;
        parent = device_get_parent(iicdev);

        if (priv->started) {
                iicbus_stop(parent);
                iicbus_reset(parent, IIC_UNKNOWN, 0, NULL);
                iicbus_release_bus(parent, iicdev);
        }

        sx_destroy(&priv->lock);
        free(priv, M_IIC);
}

static int
iicuio_move(struct iic_cdevpriv *priv, struct uio *uio, int last)
{
        device_t parent;
        int error, num_bytes, transferred_bytes, written_bytes;
        char buffer[128];

        parent = device_get_parent(priv->sc->sc_dev);
        error = 0;

        /*
         * We can only transfer up to sizeof(buffer) bytes in 1 shot, so loop until
         * everything has been transferred.
        */
        while ((error == 0) && (uio->uio_resid > 0)) {

                num_bytes = MIN(uio->uio_resid, sizeof(buffer));
                transferred_bytes = 0;

                switch (uio->uio_rw) {
                case UIO_WRITE:
                        error = uiomove(buffer, num_bytes, uio);

                        while ((error == 0) && (transferred_bytes < num_bytes)) {
                                written_bytes = 0;
                                error = iicbus_write(parent, &buffer[transferred_bytes],
                                    num_bytes - transferred_bytes, &written_bytes, 0);
                                transferred_bytes += written_bytes;
                        }
                        break;
                case UIO_READ:
                        error = iicbus_read(parent, buffer,
                            num_bytes, &transferred_bytes,
                            ((uio->uio_resid <= sizeof(buffer)) ? last : 0), 0);
                        if (error == 0)
                                error = uiomove(buffer, transferred_bytes, uio);
                        break;
                }
        }

        return (error);
}

static int
iicuio(struct cdev *dev, struct uio *uio, int ioflag)
{
        device_t parent;
        struct iic_cdevpriv *priv;
        int error;
        uint8_t addr;

        priv = NULL;
        error = devfs_get_cdevpriv((void**)&priv);

        if (error != 0)
                return (error);
        KASSERT(priv != NULL, ("iic cdevpriv should not be NULL!"));

        IIC_LOCK(priv);
        if (priv->started || (priv->addr == 0)) {
                IIC_UNLOCK(priv);
                return (ENXIO);
        }
        parent = device_get_parent(priv->sc->sc_dev);

        error = iicbus_request_bus(parent, priv->sc->sc_dev,
            (ioflag & O_NONBLOCK) ? IIC_DONTWAIT : (IIC_WAIT | IIC_INTR));
        if (error != 0) {
                IIC_UNLOCK(priv);
                return (error);
        }

        switch (uio->uio_rw) {
        case UIO_READ:
                addr = priv->addr | LSB;
                break;
        case UIO_WRITE:
                addr = priv->addr & ~LSB;
                break;
        }

        error = iicbus_start(parent, addr, 0);
        if (error != 0)
        {
                iicbus_release_bus(parent, priv->sc->sc_dev);
                IIC_UNLOCK(priv);
                return (error);
        }

        error = iicuio_move(priv, uio, IIC_LAST_READ);

        iicbus_stop(parent);
        iicbus_release_bus(parent, priv->sc->sc_dev);
        IIC_UNLOCK(priv);
        return (error);
}

#ifdef COMPAT_FREEBSD32
static int
iic_copyinmsgs32(struct iic_rdwr_data *d, struct iic_msg *buf)
{
        struct iic_msg32 msg32;
        struct iic_msg32 *m32;
        int error, i;

        m32 = (struct iic_msg32 *)d->msgs;
        for (i = 0; i < d->nmsgs; i++) {
                error = copyin(&m32[i], &msg32, sizeof(msg32));
                if (error != 0)
                        return (error);
                CP(msg32, buf[i], slave);
                CP(msg32, buf[i], flags);
                CP(msg32, buf[i], len);
                PTRIN_CP(msg32, buf[i], buf);
        }
        return (0);
}
#endif

static int
iicrdwr(struct iic_cdevpriv *priv, struct iic_rdwr_data *d, int flags,
    bool compat32 __unused)
{
#ifdef COMPAT_FREEBSD32
        struct iic_rdwr_data dswab;
        struct iic_rdwr_data32 *d32;
#endif
        struct iic_msg *buf, *m;
        void **usrbufs;
        device_t iicdev, parent;
        int error;
        uint32_t i;

        iicdev = priv->sc->sc_dev;
        parent = device_get_parent(iicdev);
        error = 0;
#ifdef COMPAT_FREEBSD32
        if (compat32) {
                d32 = (struct iic_rdwr_data32 *)d;
                PTRIN_CP(*d32, dswab, msgs);
                CP(*d32, dswab, nmsgs);
                d = &dswab;
        }
#endif

        if (d->nmsgs > IIC_RDRW_MAX_MSGS)
                return (EINVAL);

        buf = malloc(sizeof(*d->msgs) * d->nmsgs, M_IIC, M_WAITOK);

#ifdef COMPAT_FREEBSD32
        if (compat32)
                error = iic_copyinmsgs32(d, buf);
        else
#endif
        error = copyin(d->msgs, buf, sizeof(*d->msgs) * d->nmsgs);
        if (error != 0) {
                free(buf, M_IIC);
                return (error);
        }

        /* Alloc kernel buffers for userland data, copyin write data */
        usrbufs = malloc(sizeof(void *) * d->nmsgs, M_IIC, M_WAITOK | M_ZERO);

        for (i = 0; i < d->nmsgs; i++) {
                m = &(buf[i]);
                usrbufs[i] = m->buf;

                /*
                 * At least init the buffer to NULL so we can safely free() it later.
                 * If the copyin() to buf failed, don't try to malloc bogus m->len.
                 */
                m->buf = NULL;
                if (error != 0)
                        continue;

                /* m->len is uint16_t, so allocation size is capped at 64K. */
                m->buf = malloc(m->len, M_IIC, M_WAITOK);
                if (!(m->flags & IIC_M_RD))
                        error = copyin(usrbufs[i], m->buf, m->len);
        }

        if (error == 0)
                error = iicbus_request_bus(parent, iicdev,
                    (flags & O_NONBLOCK) ? IIC_DONTWAIT : (IIC_WAIT | IIC_INTR));

        if (error == 0) {
                error = iicbus_transfer(iicdev, buf, d->nmsgs);
                iicbus_release_bus(parent, iicdev);
        }

        /* Copyout all read segments, free up kernel buffers */
        for (i = 0; i < d->nmsgs; i++) {
                m = &(buf[i]);
                if ((error == 0) && (m->flags & IIC_M_RD))
                        error = copyout(m->buf, usrbufs[i], m->len);
                free(m->buf, M_IIC);
        }

        free(usrbufs, M_IIC);
        free(buf, M_IIC);
        return (error);
}

static int
iicioctl(struct cdev *dev, u_long cmd, caddr_t data, int flags, struct thread *td)
{
#ifdef COMPAT_FREEBSD32
        struct iiccmd iicswab;
#endif
        device_t parent, iicdev;
        struct iiccmd *s;
#ifdef COMPAT_FREEBSD32
        struct iiccmd32 *s32;
#endif
        struct uio ubuf;
        struct iovec uvec;
        struct iic_cdevpriv *priv;
        int error;
        bool compat32;

        s = (struct iiccmd *)data;
#ifdef COMPAT_FREEBSD32
        s32 = (struct iiccmd32 *)data;
#endif
        error = devfs_get_cdevpriv((void**)&priv);
        if (error != 0)
                return (error);

        KASSERT(priv != NULL, ("iic cdevpriv should not be NULL!"));

        iicdev = priv->sc->sc_dev;
        parent = device_get_parent(iicdev);
        IIC_LOCK(priv);

#ifdef COMPAT_FREEBSD32
        switch (cmd) {
        case I2CWRITE32:
        case I2CREAD32:
                CP(*s32, iicswab, slave);
                CP(*s32, iicswab, count);
                CP(*s32, iicswab, last);
                PTRIN_CP(*s32, iicswab, buf);
                s = &iicswab;
                break;
        default:
                break;
        }
#endif

        switch (cmd) {
        case I2CSTART:
                if (priv->started) {
                        error = EINVAL;
                        break;
                }
                error = iicbus_request_bus(parent, iicdev,
                    (flags & O_NONBLOCK) ? IIC_DONTWAIT : (IIC_WAIT | IIC_INTR));

                if (error == 0)
                        error = iicbus_start(parent, s->slave, 0);

                if (error == 0) {
                        priv->addr = s->slave;
                        priv->started = true;
                } else
                        iicbus_release_bus(parent, iicdev);

                break;

        case I2CSTOP:
                if (priv->started) {
                        error = iicbus_stop(parent);
                        iicbus_release_bus(parent, iicdev);
                        priv->started = false;
                }

                break;

        case I2CRSTCARD:
                /*
                 * Bus should be owned before we reset it.
                 * We allow the bus to be already owned as the result of an in-progress
                 * sequence; however, bus reset will always be followed by release
                 * (a new start is presumably needed for I/O anyway). */ 
                if (!priv->started)     
                        error = iicbus_request_bus(parent, iicdev,
                            (flags & O_NONBLOCK) ? IIC_DONTWAIT : (IIC_WAIT | IIC_INTR));

                if (error == 0) {
                        error = iicbus_reset(parent, IIC_UNKNOWN, 0, NULL);
                        /*
                         * Ignore IIC_ENOADDR as it only means we have a master-only
                         * controller.
                         */
                        if (error == IIC_ENOADDR)
                                error = 0;

                        iicbus_release_bus(parent, iicdev);
                        priv->started = false;
                }
                break;

        case I2CWRITE:
#ifdef COMPAT_FREEBSD32
        case I2CWRITE32:
#endif
                if (!priv->started) {
                        error = EINVAL;
                        break;
                }
                uvec.iov_base = s->buf;
                uvec.iov_len = s->count;
                ubuf.uio_iov = &uvec;
                ubuf.uio_iovcnt = 1;
                ubuf.uio_segflg = UIO_USERSPACE;
                ubuf.uio_td = td;
                ubuf.uio_resid = s->count;
                ubuf.uio_offset = 0;
                ubuf.uio_rw = UIO_WRITE;
                error = iicuio_move(priv, &ubuf, 0);
                break;

        case I2CREAD:
#ifdef COMPAT_FREEBSD32
        case I2CREAD32:
#endif
                if (!priv->started) {
                        error = EINVAL;
                        break;
                }
                uvec.iov_base = s->buf;
                uvec.iov_len = s->count;
                ubuf.uio_iov = &uvec;
                ubuf.uio_iovcnt = 1;
                ubuf.uio_segflg = UIO_USERSPACE;
                ubuf.uio_td = td;
                ubuf.uio_resid = s->count;
                ubuf.uio_offset = 0;
                ubuf.uio_rw = UIO_READ;
                error = iicuio_move(priv, &ubuf, s->last);
                break;

#ifdef COMPAT_FREEBSD32
        case I2CRDWR32:
#endif
        case I2CRDWR:
                /*
                 * The rdwr list should be a self-contained set of
                 * transactions.  Fail if another transaction is in progress.
                 */
                if (priv->started) {
                        error = EINVAL;
                        break;
                }

#ifdef COMPAT_FREEBSD32
                compat32 = (cmd == I2CRDWR32);
#else
                compat32 = false;
#endif
                error = iicrdwr(priv, (struct iic_rdwr_data *)data, flags,
                    compat32);

                break;

        case I2CRPTSTART:
                if (!priv->started) {
                        error = EINVAL;
                        break;
                }
                error = iicbus_repeated_start(parent, s->slave, 0);
                break;

        case I2CSADDR:
                priv->addr = *((uint8_t*)data);
                break;

        default:
                error = ENOTTY;
        }

        IIC_UNLOCK(priv);
        return (error);
}

DRIVER_MODULE(iic, iicbus, iic_driver, 0, 0);
MODULE_DEPEND(iic, iicbus, IICBUS_MINVER, IICBUS_PREFVER, IICBUS_MAXVER);
MODULE_VERSION(iic, 1);