/*-
 * 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 bus IP driver
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/filio.h>
#include <sys/sockio.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/bus.h>
#include <sys/time.h>
#include <sys/malloc.h>

#include <net/if.h>
#include <net/if_var.h>
#include <net/if_types.h>
#include <net/netisr.h>

#include <net/route.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#include <netinet/ip.h>
#include <netinet/if_ether.h>

#include <net/bpf.h>

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

#include "iicbus_if.h"

#define PCF_MASTER_ADDRESS 0xaa

#define ICHDRLEN        sizeof(u_int32_t)
#define ICMTU           1500            /* default mtu */

struct ic_softc {
        if_t ic_ifp;
        device_t ic_dev;

        u_char ic_addr;                 /* peer I2C address */

        int ic_flags;

        char *ic_obuf;
        char *ic_ifbuf;
        char *ic_cp;

        int ic_xfercnt;

        int ic_iferrs;

        struct mtx ic_lock;
};

#define IC_SENDING              0x0001
#define IC_OBUF_BUSY            0x0002
#define IC_IFBUF_BUSY           0x0004
#define IC_BUFFERS_BUSY         (IC_OBUF_BUSY | IC_IFBUF_BUSY)
#define IC_BUFFER_WAITER        0x0004

static int icprobe(device_t);
static int icattach(device_t);

static int icioctl(if_t, u_long, caddr_t);
static int icoutput(if_t, struct mbuf *, const struct sockaddr *,
               struct route *);

static int icintr(device_t, int, char *);

static device_method_t ic_methods[] = {
        /* device interface */
        DEVMETHOD(device_probe,         icprobe),
        DEVMETHOD(device_attach,        icattach),

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

        DEVMETHOD_END
};

static driver_t ic_driver = {
        "ic",
        ic_methods,
        sizeof(struct ic_softc),
};

static void
ic_alloc_buffers(struct ic_softc *sc, int mtu)
{
        char *obuf, *ifbuf;

        obuf = malloc(mtu + ICHDRLEN, M_DEVBUF, M_WAITOK);
        ifbuf = malloc(mtu + ICHDRLEN, M_DEVBUF, M_WAITOK);

        mtx_lock(&sc->ic_lock);
        while (sc->ic_flags & IC_BUFFERS_BUSY) {
                sc->ic_flags |= IC_BUFFER_WAITER;
                mtx_sleep(sc, &sc->ic_lock, 0, "icalloc", 0);
                sc->ic_flags &= ~IC_BUFFER_WAITER;
        }

        free(sc->ic_obuf, M_DEVBUF);
        free(sc->ic_ifbuf, M_DEVBUF);
        sc->ic_obuf = obuf;
        sc->ic_ifbuf = ifbuf;
        if_setmtu(sc->ic_ifp, mtu);
        mtx_unlock(&sc->ic_lock);
}

/*
 * icprobe()
 */
static int
icprobe(device_t dev)
{
        return (BUS_PROBE_NOWILDCARD);
}

/*
 * icattach()
 */
static int
icattach(device_t dev)
{
        struct ic_softc *sc = (struct ic_softc *)device_get_softc(dev);
        if_t ifp;

        ifp = sc->ic_ifp = if_alloc(IFT_PARA);

        mtx_init(&sc->ic_lock, device_get_nameunit(dev), MTX_NETWORK_LOCK,
            MTX_DEF);
        sc->ic_addr = PCF_MASTER_ADDRESS;       /* XXX only PCF masters */
        sc->ic_dev = dev;

        if_setsoftc(ifp, sc);
        if_initname(ifp, device_get_name(dev), device_get_unit(dev));
        if_setflags(ifp, IFF_SIMPLEX | IFF_POINTOPOINT | IFF_MULTICAST);
        if_setioctlfn(ifp, icioctl);
        if_setoutputfn(ifp, icoutput);
        if_setifheaderlen(ifp, 0);
        if_setsendqlen(ifp, ifqmaxlen);

        ic_alloc_buffers(sc, ICMTU);

        if_attach(ifp);

        bpfattach(ifp, DLT_NULL, ICHDRLEN);

        return (0);
}

/*
 * iciotcl()
 */
static int
icioctl(if_t ifp, u_long cmd, caddr_t data)
{
        struct ic_softc *sc = if_getsoftc(ifp);
        device_t icdev = sc->ic_dev;
        device_t parent = device_get_parent(icdev);
        struct ifaddr *ifa = (struct ifaddr *)data;
        struct ifreq *ifr = (struct ifreq *)data;
        int error;

        switch (cmd) {

        case SIOCAIFADDR:
        case SIOCSIFADDR:
                if (ifa->ifa_addr->sa_family != AF_INET)
                        return (EAFNOSUPPORT);
                mtx_lock(&sc->ic_lock);
                if_setflagbits(ifp, IFF_UP, 0);
                goto locked;
        case SIOCSIFFLAGS:
                mtx_lock(&sc->ic_lock);
        locked:
                if ((!(if_getflags(ifp) & IFF_UP)) &&
                    (if_getdrvflags(ifp) & IFF_DRV_RUNNING)) {

                        /* XXX disable PCF */
                        if_setdrvflagbits(ifp, 0, IFF_DRV_RUNNING);
                        mtx_unlock(&sc->ic_lock);

                        /* IFF_UP is not set, try to release the bus anyway */
                        iicbus_release_bus(parent, icdev);
                        break;
                }
                if (((if_getflags(ifp) & IFF_UP)) &&
                    (!(if_getdrvflags(ifp) & IFF_DRV_RUNNING))) {
                        mtx_unlock(&sc->ic_lock);
                        if ((error = iicbus_request_bus(parent, icdev,
                            IIC_WAIT | IIC_INTR)))
                                return (error);
                        mtx_lock(&sc->ic_lock);
                        iicbus_reset(parent, IIC_FASTEST, 0, NULL);
                        if_setdrvflagbits(ifp, IFF_DRV_RUNNING, 0);
                }
                mtx_unlock(&sc->ic_lock);
                break;

        case SIOCSIFMTU:
                ic_alloc_buffers(sc, ifr->ifr_mtu);
                break;

        case SIOCGIFMTU:
                mtx_lock(&sc->ic_lock);
                ifr->ifr_mtu = if_getmtu(sc->ic_ifp);
                mtx_unlock(&sc->ic_lock);
                break;

        case SIOCADDMULTI:
        case SIOCDELMULTI:
                if (ifr == NULL)
                        return (EAFNOSUPPORT);          /* XXX */
                switch (ifr->ifr_addr.sa_family) {
                case AF_INET:
                        break;
                default:
                        return (EAFNOSUPPORT);
                }
                break;
        default:
                return (EINVAL);
        }
        return (0);
}

/*
 * icintr()
 */
static int
icintr(device_t dev, int event, char *ptr)
{
        struct ic_softc *sc = (struct ic_softc *)device_get_softc(dev);
        struct mbuf *top;
        int len;

        mtx_lock(&sc->ic_lock);

        switch (event) {

        case INTR_GENERAL:
        case INTR_START:
                sc->ic_cp = sc->ic_ifbuf;
                sc->ic_xfercnt = 0;
                sc->ic_flags |= IC_IFBUF_BUSY;
                break;

        case INTR_STOP:

                /* if any error occurred during transfert,
                 * drop the packet */
                sc->ic_flags &= ~IC_IFBUF_BUSY;
                if ((sc->ic_flags & (IC_BUFFERS_BUSY | IC_BUFFER_WAITER)) ==
                    IC_BUFFER_WAITER)
                        wakeup(&sc);
                if (sc->ic_iferrs)
                        goto err;
                if ((len = sc->ic_xfercnt) == 0)
                        break;                                  /* ignore */
                if (len <= ICHDRLEN)
                        goto err;
                len -= ICHDRLEN;
                if_inc_counter(sc->ic_ifp, IFCOUNTER_IPACKETS, 1);
                if_inc_counter(sc->ic_ifp, IFCOUNTER_IBYTES, len);
                BPF_TAP(sc->ic_ifp, sc->ic_ifbuf, len + ICHDRLEN);
                top = m_devget(sc->ic_ifbuf + ICHDRLEN, len, 0, sc->ic_ifp, 0);
                if (top) {
                        struct epoch_tracker et;

                        mtx_unlock(&sc->ic_lock);
                        M_SETFIB(top, if_getfib(sc->ic_ifp));
                        NET_EPOCH_ENTER(et);
                        netisr_dispatch(NETISR_IP, top);
                        NET_EPOCH_EXIT(et);
                        mtx_lock(&sc->ic_lock);
                }
                break;
        err:
                if_printf(sc->ic_ifp, "errors (%d)!\n", sc->ic_iferrs);
                sc->ic_iferrs = 0;                      /* reset error count */
                if_inc_counter(sc->ic_ifp, IFCOUNTER_IERRORS, 1);
                break;

        case INTR_RECEIVE:
                if (sc->ic_xfercnt >= if_getmtu(sc->ic_ifp) + ICHDRLEN) {
                        sc->ic_iferrs++;
                } else {
                        *sc->ic_cp++ = *ptr;
                        sc->ic_xfercnt++;
                }
                break;

        case INTR_NOACK:                        /* xfer terminated by master */
                break;

        case INTR_TRANSMIT:
                *ptr = 0xff;                                    /* XXX */
                break;

        case INTR_ERROR:
                sc->ic_iferrs++;
                break;

        default:
                panic("%s: unknown event (%d)!", __func__, event);
        }

        mtx_unlock(&sc->ic_lock);
        return (0);
}

/*
 * icoutput()
 */
static int
icoutput(if_t ifp, struct mbuf *m, const struct sockaddr *dst,
    struct route *ro)
{
        struct ic_softc *sc = if_getsoftc(ifp);
        device_t icdev = sc->ic_dev;
        device_t parent = device_get_parent(icdev);
        int len, sent;
        struct mbuf *mm;
        u_char *cp;
        u_int32_t hdr;

        /* BPF writes need to be handled specially. */
        if (dst->sa_family == AF_UNSPEC || dst->sa_family == pseudo_AF_HDRCMPLT)
                bcopy(dst->sa_data, &hdr, sizeof(hdr));
        else 
                hdr = RO_GET_FAMILY(ro, dst);

        mtx_lock(&sc->ic_lock);
        if_setdrvflagbits(ifp, IFF_DRV_RUNNING, 0);

        /* already sending? */
        if (sc->ic_flags & IC_SENDING) {
                if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
                goto error;
        }
                
        /* insert header */
        bcopy ((char *)&hdr, sc->ic_obuf, ICHDRLEN);

        cp = sc->ic_obuf + ICHDRLEN;
        len = 0;
        mm = m;
        do {
                if (len + mm->m_len > if_getmtu(sc->ic_ifp)) {
                        /* packet too large */
                        if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
                        goto error;
                }
                        
                bcopy(mtod(mm,char *), cp, mm->m_len);
                cp += mm->m_len;
                len += mm->m_len;

        } while ((mm = mm->m_next));

        BPF_MTAP2(ifp, &hdr, sizeof(hdr), m);

        sc->ic_flags |= (IC_SENDING | IC_OBUF_BUSY);

        m_freem(m);
        mtx_unlock(&sc->ic_lock);

        /* send the packet */
        if (iicbus_block_write(parent, sc->ic_addr, sc->ic_obuf,
                                len + ICHDRLEN, &sent))

                if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
        else {
                if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
                if_inc_counter(ifp, IFCOUNTER_OBYTES, len);
        }       

        mtx_lock(&sc->ic_lock);
        sc->ic_flags &= ~(IC_SENDING | IC_OBUF_BUSY);
        if ((sc->ic_flags & (IC_BUFFERS_BUSY | IC_BUFFER_WAITER)) ==
            IC_BUFFER_WAITER)
                wakeup(&sc);
        mtx_unlock(&sc->ic_lock);

        return (0);

error:
        m_freem(m);
        mtx_unlock(&sc->ic_lock);

        return(0);
}

DRIVER_MODULE(ic, iicbus, ic_driver, 0, 0);
MODULE_DEPEND(ic, iicbus, IICBUS_MINVER, IICBUS_PREFVER, IICBUS_MAXVER);
MODULE_VERSION(ic, 1);