/*      $NetBSD: vmbusic.c,v 1.2 2019/10/01 18:00:08 chs Exp $  */
/*-
 * 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/cdefs.h>
#ifdef __KERNEL_RCSID
__KERNEL_RCSID(0, "$NetBSD: vmbusic.c,v 1.2 2019/10/01 18:00:08 chs Exp $");
#endif
#ifdef __FBSDID
__FBSDID("$FreeBSD: head/sys/dev/hyperv/utilities/vmbus_ic.c 310317 2016-12-20 07:14:24Z sephe $");
#endif

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/device.h>
#include <sys/kmem.h>
#include <sys/reboot.h>

#include <dev/hyperv/vmbusvar.h>
#include <dev/hyperv/vmbusicreg.h>
#include <dev/hyperv/vmbusicvar.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);


int
vmbusic_probe(struct vmbus_attach_args *aa, const struct hyperv_guid *guid)
{

        if (memcmp(aa->aa_type, guid, sizeof(*aa->aa_type)) != 0)
                return 0;
        return 1;
}

int
vmbusic_attach(device_t dv, struct vmbus_attach_args *aa,
    vmbus_channel_callback_t cb)
{
        struct vmbusic_softc *sc = device_private(dv);

        sc->sc_dev = dv;
        sc->sc_chan = aa->aa_chan;

        sc->sc_buflen = VMBUS_IC_BRSIZE;
        sc->sc_buf = kmem_alloc(sc->sc_buflen, KM_SLEEP);

        /*
         * 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.
         */
        sc->sc_chan->ch_flags &= ~CHF_BATCHED;

        if (vmbus_channel_open(sc->sc_chan, sc->sc_buflen, NULL, 0, cb, sc)) {
                aprint_error_dev(dv, "failed to open channel\n");
                kmem_free(sc->sc_buf, sc->sc_buflen);
                sc->sc_buf = NULL;
                return ENXIO;
        }

        return 0;
}

int
vmbusic_detach(device_t dv, int flags)
{
        struct vmbusic_softc *sc = device_private(dv);
        int error;

        error = vmbus_channel_close(sc->sc_chan);
        if (error != 0)
                return error;

        if (sc->sc_buf != NULL) {
                kmem_free(sc->sc_buf, sc->sc_buflen);
                sc->sc_buf = NULL;
        }

        if (sc->sc_log != NULL) {
                sysctl_teardown(&sc->sc_log);
                sc->sc_log = NULL;
        }

        return 0;
}

int
vmbusic_negotiate(struct vmbusic_softc *sc, void *data, uint32_t *dlen0,
    uint32_t fw_ver, uint32_t msg_ver)
{
        struct vmbus_icmsg_negotiate *nego;
        uint32_t sel_fw_ver = 0, sel_msg_ver = 0;
        int i, cnt, dlen = *dlen0, error;
        bool has_fw_ver, has_msg_ver = false;

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

        if (nego->ic_fwver_cnt == 0) {
                device_printf(sc->sc_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->sc_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->sc_dev, "ic negotiate does not contain "
                    "versions %d\n", dlen);
                return EINVAL;
        }

        error = EOPNOTSUPP;

        /*
         * Find the best match framework version.
         */
        has_fw_ver = false;
        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->sc_dev, "failed to select framework "
                    "version\n");
                goto done;
        }

        /*
         * Fine the best match message version.
         */
        has_msg_ver = false;
        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->sc_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->sc_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->sc_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->sc_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->sc_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->sc_fwver = sel_fw_ver;
        sc->sc_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
vmbusic_sendresp(struct vmbusic_softc *sc, struct vmbus_channel *chan,
    void *data, uint32_t dlen, uint64_t rid)
{
        struct vmbus_icmsg_hdr *hdr;
        int error;

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

        hdr->ic_flags = VMBUS_ICMSG_FLAG_TRANSACTION|VMBUS_ICMSG_FLAG_RESPONSE;
        error = vmbus_channel_send(chan, data, dlen, rid,
            VMBUS_CHANPKT_TYPE_INBAND, 0);
        if (error != 0)
                device_printf(sc->sc_dev, "resp send failed: %d\n", error);
        return error;
}