/*-
 * Copyright (c) 2014,2016 Microsoft Corp.
 * 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 unmodified, 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 ``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 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/bus.h>
#include <sys/malloc.h>
#include <sys/systm.h>
#include <sys/sysctl.h>

#include <dev/hyperv/include/hyperv.h>
#include <dev/hyperv/include/vmbus.h>
#include <dev/hyperv/utilities/vmbus_icreg.h>
#include <dev/hyperv/utilities/vmbus_icvar.h>

#include "vmbus_if.h"

#define VMBUS_IC_BRSIZE         (4 * PAGE_SIZE)

#define VMBUS_IC_VERCNT         2
#define VMBUS_IC_NEGOSZ         \
        __offsetof(struct vmbus_icmsg_negotiate, ic_ver[VMBUS_IC_VERCNT])
CTASSERT(VMBUS_IC_NEGOSZ < VMBUS_IC_BRSIZE);

static int      vmbus_ic_fwver_sysctl(SYSCTL_HANDLER_ARGS);
static int      vmbus_ic_msgver_sysctl(SYSCTL_HANDLER_ARGS);

int
vmbus_ic_negomsg(struct vmbus_ic_softc *sc, void *data, int *dlen0,
    uint32_t fw_ver, uint32_t msg_ver)
{
        struct vmbus_icmsg_negotiate *nego;
        int i, cnt, dlen = *dlen0, error;
        uint32_t sel_fw_ver, sel_msg_ver;
        bool has_fw_ver, has_msg_ver;

        has_fw_ver = false;
        has_msg_ver = false;

        /*
         * Preliminary message verification.
         */
        if (dlen < sizeof(*nego)) {
                device_printf(sc->ic_dev, "truncated ic negotiate, len %d\n",
                    dlen);
                return (EINVAL);
        }
        nego = data;

        if (nego->ic_fwver_cnt == 0) {
                device_printf(sc->ic_dev, "ic negotiate does not contain "
                    "framework version %u\n", nego->ic_fwver_cnt);
                return (EINVAL);
        }
        if (nego->ic_msgver_cnt == 0) {
                device_printf(sc->ic_dev, "ic negotiate does not contain "
                    "message version %u\n", nego->ic_msgver_cnt);
                return (EINVAL);
        }

        cnt = nego->ic_fwver_cnt + nego->ic_msgver_cnt;
        if (dlen < __offsetof(struct vmbus_icmsg_negotiate, ic_ver[cnt])) {
                device_printf(sc->ic_dev, "ic negotiate does not contain "
                    "versions %d\n", dlen);
                return (EINVAL);
        }

        error = EOPNOTSUPP;

        /*
         * Find the best match framework version.
         */
        for (i = 0; i < nego->ic_fwver_cnt; ++i) {
                if (VMBUS_ICVER_LE(nego->ic_ver[i], fw_ver)) {
                        if (!has_fw_ver) {
                                sel_fw_ver = nego->ic_ver[i];
                                has_fw_ver = true;
                        } else if (VMBUS_ICVER_GT(nego->ic_ver[i],
                            sel_fw_ver)) {
                                sel_fw_ver = nego->ic_ver[i];
                        }
                }
        }
        if (!has_fw_ver) {
                device_printf(sc->ic_dev, "failed to select framework "
                    "version\n");
                goto done;
        }

        /*
         * Find the best match message version.
         */
        for (i = nego->ic_fwver_cnt;
            i < nego->ic_fwver_cnt + nego->ic_msgver_cnt; ++i) {
                if (VMBUS_ICVER_LE(nego->ic_ver[i], msg_ver)) {
                        if (!has_msg_ver) {
                                sel_msg_ver = nego->ic_ver[i];
                                has_msg_ver = true;
                        } else if (VMBUS_ICVER_GT(nego->ic_ver[i],
                            sel_msg_ver)) {
                                sel_msg_ver = nego->ic_ver[i];
                        }
                }
        }
        if (!has_msg_ver) {
                device_printf(sc->ic_dev, "failed to select message "
                    "version\n");
                goto done;
        }

        error = 0;
done:
        if (bootverbose || !has_fw_ver || !has_msg_ver) {
                if (has_fw_ver) {
                        device_printf(sc->ic_dev, "sel framework version: "
                            "%u.%u\n",
                            VMBUS_ICVER_MAJOR(sel_fw_ver),
                            VMBUS_ICVER_MINOR(sel_fw_ver));
                }
                for (i = 0; i < nego->ic_fwver_cnt; i++) {
                        device_printf(sc->ic_dev, "supp framework version: "
                            "%u.%u\n",
                            VMBUS_ICVER_MAJOR(nego->ic_ver[i]),
                            VMBUS_ICVER_MINOR(nego->ic_ver[i]));
                }

                if (has_msg_ver) {
                        device_printf(sc->ic_dev, "sel message version: "
                            "%u.%u\n",
                            VMBUS_ICVER_MAJOR(sel_msg_ver),
                            VMBUS_ICVER_MINOR(sel_msg_ver));
                }
                for (i = nego->ic_fwver_cnt;
                    i < nego->ic_fwver_cnt + nego->ic_msgver_cnt; i++) {
                        device_printf(sc->ic_dev, "supp message version: "
                            "%u.%u\n",
                            VMBUS_ICVER_MAJOR(nego->ic_ver[i]),
                            VMBUS_ICVER_MINOR(nego->ic_ver[i]));
                }
        }
        if (error)
                return (error);

        /* Record the selected versions. */
        sc->ic_fwver = sel_fw_ver;
        sc->ic_msgver = sel_msg_ver;

        /* One framework version. */
        nego->ic_fwver_cnt = 1;
        nego->ic_ver[0] = sel_fw_ver;

        /* One message version. */
        nego->ic_msgver_cnt = 1;
        nego->ic_ver[1] = sel_msg_ver;

        /* Update data size. */
        nego->ic_hdr.ic_dsize = VMBUS_IC_NEGOSZ -
            sizeof(struct vmbus_icmsg_hdr);

        /* Update total size, if necessary. */
        if (dlen < VMBUS_IC_NEGOSZ)
                *dlen0 = VMBUS_IC_NEGOSZ;

        return (0);
}

int
vmbus_ic_probe(device_t dev, const struct vmbus_ic_desc descs[])
{
        device_t bus = device_get_parent(dev);
        const struct vmbus_ic_desc *d;

        if (resource_disabled(device_get_name(dev), 0))
                return (ENXIO);

        for (d = descs; d->ic_desc != NULL; ++d) {
                if (VMBUS_PROBE_GUID(bus, dev, &d->ic_guid) == 0) {
                        device_set_desc(dev, d->ic_desc);
                        return (BUS_PROBE_DEFAULT);
                }
        }
        return (ENXIO);
}

int
vmbus_ic_attach(device_t dev, vmbus_chan_callback_t cb)
{
        struct vmbus_ic_softc *sc = device_get_softc(dev);
        struct vmbus_channel *chan = vmbus_get_channel(dev);
        struct sysctl_oid_list *child;
        struct sysctl_ctx_list *ctx;
        int error;

        sc->ic_dev = dev;
        sc->ic_buflen = VMBUS_IC_BRSIZE;
        sc->ic_buf = malloc(VMBUS_IC_BRSIZE, M_DEVBUF, M_WAITOK | M_ZERO);

        /*
         * These services are not performance critical and do not need
         * batched reading. Furthermore, some services such as KVP can
         * only handle one message from the host at a time.
         * Turn off batched reading for all util drivers before we open the
         * channel.
         */
        vmbus_chan_set_readbatch(chan, false);

        error = vmbus_chan_open(chan, VMBUS_IC_BRSIZE, VMBUS_IC_BRSIZE, NULL, 0,
            cb, sc);
        if (error) {
                free(sc->ic_buf, M_DEVBUF);
                return (error);
        }

        ctx = device_get_sysctl_ctx(dev);
        child = SYSCTL_CHILDREN(device_get_sysctl_tree(dev));
        SYSCTL_ADD_PROC(ctx, child, OID_AUTO, "fw_version",
            CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, sc, 0,
            vmbus_ic_fwver_sysctl, "A", "framework version");
        SYSCTL_ADD_PROC(ctx, child, OID_AUTO, "msg_version",
            CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, sc, 0,
            vmbus_ic_msgver_sysctl, "A", "message version");

        return (0);
}

static int
vmbus_ic_fwver_sysctl(SYSCTL_HANDLER_ARGS)
{
        struct vmbus_ic_softc *sc = arg1;
        char verstr[16];

        snprintf(verstr, sizeof(verstr), "%u.%u",
            VMBUS_ICVER_MAJOR(sc->ic_fwver), VMBUS_ICVER_MINOR(sc->ic_fwver));
        return sysctl_handle_string(oidp, verstr, sizeof(verstr), req);
}

static int
vmbus_ic_msgver_sysctl(SYSCTL_HANDLER_ARGS)
{
        struct vmbus_ic_softc *sc = arg1;
        char verstr[16];

        snprintf(verstr, sizeof(verstr), "%u.%u",
            VMBUS_ICVER_MAJOR(sc->ic_msgver), VMBUS_ICVER_MINOR(sc->ic_msgver));
        return sysctl_handle_string(oidp, verstr, sizeof(verstr), req);
}

int
vmbus_ic_detach(device_t dev)
{
        struct vmbus_ic_softc *sc = device_get_softc(dev);

        vmbus_chan_close(vmbus_get_channel(dev));
        free(sc->ic_buf, M_DEVBUF);

        return (0);
}

int
vmbus_ic_sendresp(struct vmbus_ic_softc *sc, struct vmbus_channel *chan,
    void *data, int dlen, uint64_t xactid)
{
        struct vmbus_icmsg_hdr *hdr;
        int error;

        KASSERT(dlen >= sizeof(*hdr), ("invalid data length %d", dlen));
        hdr = data;

        hdr->ic_flags = VMBUS_ICMSG_FLAG_XACT | VMBUS_ICMSG_FLAG_RESP;
        error = vmbus_chan_send(chan, VMBUS_CHANPKT_TYPE_INBAND, 0,
            data, dlen, xactid);
        if (error)
                device_printf(sc->ic_dev, "resp send failed: %d\n", error);
        return (error);
}