/*-
 * Copyright (c) 2017 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/kernel.h>
#include <sys/conf.h>
#include <sys/uio.h>
#include <sys/bus.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/module.h>
#include <sys/lock.h>
#include <sys/taskqueue.h>
#include <sys/selinfo.h>
#include <sys/sysctl.h>
#include <sys/poll.h>
#include <sys/proc.h>
#include <sys/queue.h>
#include <sys/syscallsubr.h>
#include <sys/sysproto.h>
#include <sys/systm.h>
#include <sys/mutex.h>

#include <sys/kbio.h>
#include <dev/kbd/kbdreg.h>

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

#include "dev/hyperv/input/hv_kbdc.h"
#include "vmbus_if.h"

#define HV_KBD_VER_MAJOR        (1)
#define HV_KBD_VER_MINOR        (0)

#define HV_KBD_VER              (HV_KBD_VER_MINOR | (HV_KBD_VER_MAJOR) << 16)

#define HV_KBD_PROTO_ACCEPTED   (1)

#define HV_BUFF_SIZE            (4*PAGE_SIZE)
#define HV_KBD_RINGBUFF_SEND_SZ (10*PAGE_SIZE)
#define HV_KBD_RINGBUFF_RECV_SZ (10*PAGE_SIZE)

enum hv_kbd_msg_type_t {
        HV_KBD_PROTO_REQUEST        = 1,
        HV_KBD_PROTO_RESPONSE       = 2,
        HV_KBD_PROTO_EVENT          = 3,
        HV_KBD_PROTO_LED_INDICATORS = 4,
};

typedef struct hv_kbd_msg_hdr_t {
        uint32_t type;
} hv_kbd_msg_hdr;

typedef struct hv_kbd_msg_t {
        hv_kbd_msg_hdr hdr;
        char data[];
} hv_kbd_msg;

typedef struct hv_kbd_proto_req_t {
        hv_kbd_msg_hdr  hdr;
        uint32_t        ver;
} hv_kbd_proto_req;

typedef struct hv_kbd_proto_resp_t {
        hv_kbd_msg_hdr  hdr;
        uint32_t        status;
} hv_kbd_proto_resp;

#define HV_KBD_PROTO_REQ_SZ     (sizeof(hv_kbd_proto_req))
#define HV_KBD_PROTO_RESP_SZ    (sizeof(hv_kbd_proto_resp))

/**
 * the struct in win host:
 * typedef struct _HK_MESSAGE_KEYSTROKE
 * {
 *     HK_MESSAGE_HEADER Header;
 *     UINT16 MakeCode;
 *     UINT32 IsUnicode:1;
 *     UINT32 IsBreak:1;
 *     UINT32 IsE0:1;
 *     UINT32 IsE1:1;
 *     UINT32 Reserved:28;
 * } HK_MESSAGE_KEYSTROKE
 */
typedef struct hv_kbd_keystroke_t {
        hv_kbd_msg_hdr  hdr;
        keystroke       ks;
} hv_kbd_keystroke;

static const struct vmbus_ic_desc vmbus_kbd_descs[] = {
        {
                .ic_guid = { .hv_guid = {
                    0x6d, 0xad, 0x12, 0xf9, 0x17, 0x2b, 0xea, 0x48,
                    0xbd, 0x65, 0xf9, 0x27, 0xa6, 0x1c, 0x76,  0x84} },
                .ic_desc = "Hyper-V KBD"
        },
        VMBUS_IC_DESC_END
};

static int hv_kbd_attach(device_t dev);
static int hv_kbd_detach(device_t dev);

/**
 * return 1 if producer is ready
 */
int
hv_kbd_prod_is_ready(hv_kbd_sc *sc)
{
        int ret;
        mtx_lock(&sc->ks_mtx);
        ret = !STAILQ_EMPTY(&sc->ks_queue);
        mtx_unlock(&sc->ks_mtx);
        return (ret);
}

int
hv_kbd_produce_ks(hv_kbd_sc *sc, const keystroke *ks)
{
        int ret = 0;
        keystroke_info *ksi;
        mtx_lock(&sc->ks_mtx);
        if (LIST_EMPTY(&sc->ks_free_list)) {
                DEBUG_HVSC(sc, "NO buffer!\n");
                ret = 1;
        } else {
                ksi = LIST_FIRST(&sc->ks_free_list);
                LIST_REMOVE(ksi, link);
                ksi->ks = *ks;
                STAILQ_INSERT_TAIL(&sc->ks_queue, ksi, slink);
        }
        mtx_unlock(&sc->ks_mtx);
        return (ret);
}

/**
 * return 0 if successfully get the 1st item of queue without removing it
 */
int
hv_kbd_fetch_top(hv_kbd_sc *sc, keystroke *result)
{
        int ret = 0;
        keystroke_info *ksi = NULL;
        mtx_lock(&sc->ks_mtx);
        if (STAILQ_EMPTY(&sc->ks_queue)) {
                DEBUG_HVSC(sc, "Empty queue!\n");
                ret = 1;
        } else {
                ksi = STAILQ_FIRST(&sc->ks_queue);
                *result = ksi->ks;
        }
        mtx_unlock(&sc->ks_mtx);
        return (ret);
}

/**
 * return 0 if successfully removing the top item
 */
int
hv_kbd_remove_top(hv_kbd_sc *sc)
{
        int ret = 0;
        keystroke_info *ksi = NULL;
        mtx_lock(&sc->ks_mtx);
        if (STAILQ_EMPTY(&sc->ks_queue)) {
                DEBUG_HVSC(sc, "Empty queue!\n");
                ret = 1;
        } else {
                ksi = STAILQ_FIRST(&sc->ks_queue);
                STAILQ_REMOVE_HEAD(&sc->ks_queue, slink);
                LIST_INSERT_HEAD(&sc->ks_free_list, ksi, link);
        }
        mtx_unlock(&sc->ks_mtx);
        return (ret);
}

/**
 * return 0 if successfully modify the 1st item of queue
 */
int
hv_kbd_modify_top(hv_kbd_sc *sc, keystroke *top)
{
        int ret = 0;
        keystroke_info *ksi = NULL;
        mtx_lock(&sc->ks_mtx);
        if (STAILQ_EMPTY(&sc->ks_queue)) {
                DEBUG_HVSC(sc, "Empty queue!\n");
                ret = 1;
        } else {
                ksi = STAILQ_FIRST(&sc->ks_queue);
                ksi->ks = *top;
        }
        mtx_unlock(&sc->ks_mtx);
        return (ret);
}

static int
hv_kbd_probe(device_t dev)
{
        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 = vmbus_kbd_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);
}

static void
hv_kbd_on_response(hv_kbd_sc *sc, struct vmbus_chanpkt_hdr *pkt)
{
        struct vmbus_xact_ctx *xact = sc->hs_xact_ctx;
        if (xact != NULL) {
                DEBUG_HVSC(sc, "hvkbd is ready\n");
                vmbus_xact_ctx_wakeup(xact, VMBUS_CHANPKT_CONST_DATA(pkt),
                    VMBUS_CHANPKT_DATALEN(pkt));
        }
}

static void
hv_kbd_on_received(hv_kbd_sc *sc, struct vmbus_chanpkt_hdr *pkt)
{

        const hv_kbd_msg *msg = VMBUS_CHANPKT_CONST_DATA(pkt);
        const hv_kbd_proto_resp *resp =
            VMBUS_CHANPKT_CONST_DATA(pkt);
        const hv_kbd_keystroke *keystroke =
            VMBUS_CHANPKT_CONST_DATA(pkt);
        uint32_t msg_len = VMBUS_CHANPKT_DATALEN(pkt);
        enum hv_kbd_msg_type_t msg_type;
        uint32_t info;
        uint16_t scan_code;

        if (msg_len <= sizeof(hv_kbd_msg)) {
                device_printf(sc->dev, "Illegal packet\n");
                return;
        }
        msg_type = msg->hdr.type;
        switch (msg_type) {
                case HV_KBD_PROTO_RESPONSE:
                        hv_kbd_on_response(sc, pkt);
                        DEBUG_HVSC(sc, "keyboard resp: 0x%x\n",
                            resp->status);
                        break;
                case HV_KBD_PROTO_EVENT:
                        info = keystroke->ks.info;
                        scan_code = keystroke->ks.makecode;
                        DEBUG_HVSC(sc, "keystroke info: 0x%x, scan: 0x%x\n",
                            info, scan_code);
                        hv_kbd_produce_ks(sc, &keystroke->ks);
                        hv_kbd_intr(sc);
                default:
                        break;
        }
}

void 
hv_kbd_read_channel(struct vmbus_channel *channel, void *context)
{
        uint8_t *buf;
        uint32_t buflen = 0;
        int ret = 0;

        hv_kbd_sc *sc = (hv_kbd_sc*)context;
        buf = sc->buf;
        buflen = sc->buflen;
        for (;;) {
                struct vmbus_chanpkt_hdr *pkt = (struct vmbus_chanpkt_hdr *)buf;
                uint32_t rxed = buflen;

                ret = vmbus_chan_recv_pkt(channel, pkt, &rxed);
                if (__predict_false(ret == ENOBUFS)) {
                        buflen = sc->buflen * 2;
                        while (buflen < rxed)
                                buflen *= 2;
                        buf = malloc(buflen, M_DEVBUF, M_WAITOK | M_ZERO);
                        device_printf(sc->dev, "expand recvbuf %d -> %d\n",
                            sc->buflen, buflen);
                        free(sc->buf, M_DEVBUF);
                        sc->buf = buf;
                        sc->buflen = buflen;
                        continue;
                } else if (__predict_false(ret == EAGAIN)) {
                        /* No more channel packets; done! */
                        break;
                }
                KASSERT(!ret, ("vmbus_chan_recv_pkt failed: %d", ret));

                DEBUG_HVSC(sc, "event: 0x%x\n", pkt->cph_type);
                switch (pkt->cph_type) {
                case VMBUS_CHANPKT_TYPE_COMP:
                case VMBUS_CHANPKT_TYPE_RXBUF:
                        device_printf(sc->dev, "unhandled event: %d\n",
                            pkt->cph_type);
                        break;
                case VMBUS_CHANPKT_TYPE_INBAND:
                        hv_kbd_on_received(sc, pkt);
                        break;
                default:
                        device_printf(sc->dev, "unknown event: %d\n",
                            pkt->cph_type);
                        break;
                }
        }
}

static int
hv_kbd_connect_vsp(hv_kbd_sc *sc)
{
        int ret;
        size_t resplen;
        struct vmbus_xact *xact;
        hv_kbd_proto_req *req;
        const hv_kbd_proto_resp *resp;

        xact = vmbus_xact_get(sc->hs_xact_ctx, sizeof(*req));
        if (xact == NULL) {
                device_printf(sc->dev, "no xact for kbd init");
                return (ENODEV);
        }
        req = vmbus_xact_req_data(xact);
        req->hdr.type = HV_KBD_PROTO_REQUEST;
        req->ver = HV_KBD_VER;

        vmbus_xact_activate(xact);
        ret = vmbus_chan_send(sc->hs_chan,
                VMBUS_CHANPKT_TYPE_INBAND,
                VMBUS_CHANPKT_FLAG_RC,
                req, sizeof(hv_kbd_proto_req),
                (uint64_t)(uintptr_t)xact);
        if (ret) {
                device_printf(sc->dev, "fail to send\n");
                vmbus_xact_deactivate(xact);
                return (ret);
        }
        resp = vmbus_chan_xact_wait(sc->hs_chan, xact, &resplen, true);
        if (resplen < HV_KBD_PROTO_RESP_SZ) {
                device_printf(sc->dev, "hv_kbd init communicate failed\n");
                ret = ENODEV;
                goto clean;
        }

        if (!(resp->status & HV_KBD_PROTO_ACCEPTED)) {
                device_printf(sc->dev, "hv_kbd protocol request failed\n");
                ret = ENODEV;
        }
clean:
        vmbus_xact_put(xact);
        DEBUG_HVSC(sc, "finish connect vsp\n");
        return (ret);
}

static int
hv_kbd_attach1(device_t dev, vmbus_chan_callback_t cb)
{
        int ret;
        hv_kbd_sc *sc;

        sc = device_get_softc(dev);
        sc->buflen = HV_BUFF_SIZE;
        sc->buf = malloc(sc->buflen, M_DEVBUF, M_WAITOK | M_ZERO);
        vmbus_chan_set_readbatch(sc->hs_chan, false);
        ret = vmbus_chan_open(
                sc->hs_chan,
                HV_KBD_RINGBUFF_SEND_SZ,
                HV_KBD_RINGBUFF_RECV_SZ,
                NULL, 0,
                cb,
                sc);
        if (ret != 0) {
                free(sc->buf, M_DEVBUF);
        }
        return (ret);
}

static int
hv_kbd_detach1(device_t dev)
{
        hv_kbd_sc *sc = device_get_softc(dev);
        vmbus_chan_close(vmbus_get_channel(dev));
        free(sc->buf, M_DEVBUF);
        return (0);
}

static void
hv_kbd_init(hv_kbd_sc *sc)
{
        const int max_list = 16;
        int i;
        keystroke_info *ksi;

        mtx_init(&sc->ks_mtx, "hv_kbdc mutex", NULL, MTX_DEF);
        LIST_INIT(&sc->ks_free_list);
        STAILQ_INIT(&sc->ks_queue);
        for (i = 0; i < max_list; i++) {
                ksi = malloc(sizeof(keystroke_info),
                    M_DEVBUF, M_WAITOK|M_ZERO);
                LIST_INSERT_HEAD(&sc->ks_free_list, ksi, link);
        }
}

static void
hv_kbd_fini(hv_kbd_sc *sc)
{
        keystroke_info *ksi;
        while (!LIST_EMPTY(&sc->ks_free_list)) {
                ksi = LIST_FIRST(&sc->ks_free_list);
                LIST_REMOVE(ksi, link);
                free(ksi, M_DEVBUF);
        }
        while (!STAILQ_EMPTY(&sc->ks_queue)) {
                ksi = STAILQ_FIRST(&sc->ks_queue);
                STAILQ_REMOVE_HEAD(&sc->ks_queue, slink);
                free(ksi, M_DEVBUF);
        }
        mtx_destroy(&sc->ks_mtx);
}

static void
hv_kbd_sysctl(device_t dev)
{
        struct sysctl_oid_list *child;
        struct sysctl_ctx_list *ctx;
        hv_kbd_sc *sc;

        sc = device_get_softc(dev);
        ctx = device_get_sysctl_ctx(dev);
        child = SYSCTL_CHILDREN(device_get_sysctl_tree(dev));
        SYSCTL_ADD_INT(ctx, child, OID_AUTO, "debug", CTLFLAG_RW,
            &sc->debug, 0, "debug hyperv keyboard");
}

static int
hv_kbd_attach(device_t dev)
{
        int error = 0;
        hv_kbd_sc *sc;

        sc = device_get_softc(dev);
        sc->hs_chan = vmbus_get_channel(dev);
        sc->dev = dev;
        hv_kbd_init(sc);
        sc->hs_xact_ctx = vmbus_xact_ctx_create(bus_get_dma_tag(dev),
            HV_KBD_PROTO_REQ_SZ, HV_KBD_PROTO_RESP_SZ, 0);
        if (sc->hs_xact_ctx == NULL) {
                error = ENOMEM;
                goto failed;
        }

        error = hv_kbd_attach1(dev, hv_kbd_read_channel);
        if (error)
                goto failed;
        error = hv_kbd_connect_vsp(sc);
        if (error)
                goto failed;

        error = hv_kbd_drv_attach(dev);
        if (error)
                goto failed;
        hv_kbd_sysctl(dev);
        return (0);
failed:
        hv_kbd_detach(dev);
        return (error);
}

static int
hv_kbd_detach(device_t dev)
{
        int ret;
        hv_kbd_sc *sc = device_get_softc(dev);
        hv_kbd_fini(sc);
        if (sc->hs_xact_ctx != NULL)
                vmbus_xact_ctx_destroy(sc->hs_xact_ctx);
        ret = hv_kbd_detach1(dev);
        if (!ret)
                device_printf(dev, "Fail to detach\n");
        return hv_kbd_drv_detach(dev);
}

static device_method_t kbd_methods[] = {
        /* Device interface */
        DEVMETHOD(device_probe, hv_kbd_probe),
        DEVMETHOD(device_attach, hv_kbd_attach),
        DEVMETHOD(device_detach, hv_kbd_detach),
        DEVMETHOD_END
};

static driver_t kbd_driver = {HVKBD_DRIVER_NAME , kbd_methods, sizeof(hv_kbd_sc)};

DRIVER_MODULE(hv_kbd, vmbus, kbd_driver, hvkbd_driver_load, NULL);
MODULE_VERSION(hv_kbd, 1);
MODULE_DEPEND(hv_kbd, vmbus, 1, 1, 1);