/*-
 * Copyright (c) 2017 Microsoft Corp.
 * Copyright (c) 2023 Yuri <yuri@aetern.org>
 *
 * 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/cdefs.h>
#include <sys/conf.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/mutex.h>

#include <dev/evdev/input.h>

#include <dev/hid/hid.h>

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

#include "hid_if.h"
#include "vmbus_if.h"

#define HV_HID_VER_MAJOR        2
#define HV_HID_VER_MINOR        0
#define HV_HID_VER              (HV_HID_VER_MINOR | (HV_HID_VER_MAJOR) << 16)

#define HV_BUFSIZ               (4 * PAGE_SIZE)
#define HV_HID_RINGBUFF_SEND_SZ (10 * PAGE_SIZE)
#define HV_HID_RINGBUFF_RECV_SZ (10 * PAGE_SIZE)

typedef struct {
        device_t                dev;
        struct mtx              mtx;
        /* vmbus */
        struct vmbus_channel    *hs_chan;
        struct vmbus_xact_ctx   *hs_xact_ctx;
        uint8_t                 *buf;
        int                     buflen;
        /* hid */
        struct hid_device_info  hdi;
        hid_intr_t              *intr;
        bool                    intr_on;
        void                    *intr_ctx;
        uint8_t                 *rdesc;
} hv_hid_sc;

typedef enum {
        SH_PROTO_REQ,
        SH_PROTO_RESP,
        SH_DEVINFO,
        SH_DEVINFO_ACK,
        SH_INPUT_REPORT,
} sh_msg_type;

typedef struct {
        sh_msg_type     type;
        uint32_t        size;
} __packed sh_msg_hdr;

typedef struct {
        sh_msg_hdr      hdr;
        char            data[];
} __packed sh_msg;

typedef struct {
        sh_msg_hdr      hdr;
        uint32_t        ver;
} __packed sh_proto_req;

typedef struct {
        sh_msg_hdr      hdr;
        uint32_t        ver;
        uint32_t        app;
} __packed sh_proto_resp;

typedef struct {
        u_int           size;
        u_short         vendor;
        u_short         product;
        u_short         version;
        u_short         reserved[11];
} __packed sh_devinfo;

/* Copied from linux/hid.h */
typedef struct {
        uint8_t         bDescriptorType;
        uint16_t        wDescriptorLength;
} __packed sh_hcdesc;

typedef struct {
        uint8_t         bLength;
        uint8_t         bDescriptorType;
        uint16_t        bcdHID;
        uint8_t         bCountryCode;
        uint8_t         bNumDescriptors;
        sh_hcdesc       hcdesc[1];
} __packed sh_hdesc;

typedef struct {
        sh_msg_hdr      hdr;
        sh_devinfo      devinfo;
        sh_hdesc        hdesc;
} __packed sh_devinfo_resp;

typedef struct {
        sh_msg_hdr      hdr;
        uint8_t         rsvd;
} __packed sh_devinfo_ack;

typedef struct {
        sh_msg_hdr      hdr;
        char            buffer[];
} __packed sh_input_report;

typedef enum {
        HV_HID_MSG_INVALID,
        HV_HID_MSG_DATA,
} hv_hid_msg_type;

typedef struct {
        hv_hid_msg_type type;
        uint32_t        size;
        char            data[];
} hv_hid_pmsg;

typedef struct {
        hv_hid_msg_type type;
        uint32_t        size;
        union {
                sh_msg          msg;
                sh_proto_req    req;
                sh_proto_resp   resp;
                sh_devinfo_resp dresp;
                sh_devinfo_ack  ack;
                sh_input_report irep;
        };
} hv_hid_msg;

#define HV_HID_REQ_SZ   (sizeof(hv_hid_pmsg) + sizeof(sh_proto_req))
#define HV_HID_RESP_SZ  (sizeof(hv_hid_pmsg) + sizeof(sh_proto_resp))
#define HV_HID_ACK_SZ   (sizeof(hv_hid_pmsg) + sizeof(sh_devinfo_ack))

/* Somewhat arbitrary, enough to get the devinfo response */
#define HV_HID_REQ_MAX  256
#define HV_HID_RESP_MAX 256

static const struct vmbus_ic_desc vmbus_hid_descs[] = {
        {
                .ic_guid = { .hv_guid = {
                    0x9e, 0xb6, 0xa8, 0xcf, 0x4a, 0x5b, 0xc0, 0x4c,
                    0xb9, 0x8b, 0x8b, 0xa1, 0xa1, 0xf3, 0xf9, 0x5a} },
                .ic_desc = "Hyper-V HID device"
        },
        VMBUS_IC_DESC_END
};

/* TODO: add GUID support to devmatch(8) to export vmbus_hid_descs directly */
const struct {
        char *guid;
} vmbus_hid_descs_pnp[] = {{ "cfa8b69e-5b4a-4cc0-b98b-8ba1a1f3f95a" }};

static int hv_hid_attach(device_t dev);
static int hv_hid_detach(device_t dev);

static int
hv_hid_connect_vsp(hv_hid_sc *sc)
{
        struct vmbus_xact       *xact;
        hv_hid_msg              *req;
        const hv_hid_msg        *resp;
        size_t                  resplen;
        int                     ret;

        xact = vmbus_xact_get(sc->hs_xact_ctx, HV_HID_REQ_SZ);
        if (xact == NULL) {
                device_printf(sc->dev, "no xact for init");
                return (ENODEV);
        }
        req = vmbus_xact_req_data(xact);
        req->type = HV_HID_MSG_DATA;
        req->size = sizeof(sh_proto_req);
        req->req.hdr.type = SH_PROTO_REQ;
        req->req.hdr.size = sizeof(u_int);
        req->req.ver = HV_HID_VER;

        vmbus_xact_activate(xact);
        ret = vmbus_chan_send(sc->hs_chan,
            VMBUS_CHANPKT_TYPE_INBAND,
            VMBUS_CHANPKT_FLAG_RC,
            req, HV_HID_REQ_SZ, (uint64_t)(uintptr_t)xact);
        if (ret != 0) {
                device_printf(sc->dev, "failed to send proto req\n");
                vmbus_xact_deactivate(xact);
                return (ret);
        }
        resp = vmbus_chan_xact_wait(sc->hs_chan, xact, &resplen, true);
        if (resplen != HV_HID_RESP_SZ || !resp->resp.app) {
                device_printf(sc->dev, "proto req failed\n");
                ret = ENODEV;
        }

        vmbus_xact_put(xact);
        return (ret);
}

static void
hv_hid_receive(hv_hid_sc *sc, struct vmbus_chanpkt_hdr *pkt)
{
        const hv_hid_msg        *msg;
        sh_msg_type             msg_type;
        uint32_t                msg_len;
        void                    *rdesc;

        msg = VMBUS_CHANPKT_CONST_DATA(pkt);
        msg_len = VMBUS_CHANPKT_DATALEN(pkt);

        if (msg->type != HV_HID_MSG_DATA)
                return;

        if (msg_len <= sizeof(hv_hid_pmsg)) {
                device_printf(sc->dev, "invalid packet length\n");
                return;
        }
        msg_type = msg->msg.hdr.type;
        switch (msg_type) {
        case SH_PROTO_RESP: {
                struct vmbus_xact_ctx *xact_ctx;

                xact_ctx = sc->hs_xact_ctx;
                if (xact_ctx != NULL) {
                        vmbus_xact_ctx_wakeup(xact_ctx,
                            VMBUS_CHANPKT_CONST_DATA(pkt),
                            VMBUS_CHANPKT_DATALEN(pkt));
                }
                break;
        }
        case SH_DEVINFO: {
                struct vmbus_xact       *xact;
                struct hid_device_info  *hdi;
                hv_hid_msg              ack;
                const sh_devinfo        *devinfo;
                const sh_hdesc          *hdesc;

                /* Send ack */
                ack.type = HV_HID_MSG_DATA;
                ack.size = sizeof(sh_devinfo_ack);
                ack.ack.hdr.type = SH_DEVINFO_ACK;
                ack.ack.hdr.size = 1;
                ack.ack.rsvd = 0;

                xact = vmbus_xact_get(sc->hs_xact_ctx, HV_HID_ACK_SZ);
                if (xact == NULL)
                        break;
                vmbus_xact_activate(xact);
                (void) vmbus_chan_send(sc->hs_chan, VMBUS_CHANPKT_TYPE_INBAND,
                    0, &ack, HV_HID_ACK_SZ, (uint64_t)(uintptr_t)xact);
                vmbus_xact_deactivate(xact);
                vmbus_xact_put(xact);

                /* Check for resume from hibernation */
                if (sc->rdesc != NULL)
                        break;

                /* Parse devinfo response */
                devinfo = &msg->dresp.devinfo;
                hdesc = &msg->dresp.hdesc;
                if (hdesc->bLength == 0)
                        break;
                hdi = &sc->hdi;
                memset(hdi, 0, sizeof(*hdi));
                hdi->rdescsize = le16toh(hdesc->hcdesc[0].wDescriptorLength);
                if (hdi->rdescsize == 0)
                        break;
                strlcpy(hdi->name, "Hyper-V", sizeof(hdi->name));
                hdi->idBus = BUS_VIRTUAL;
                hdi->idVendor = le16toh(devinfo->vendor);
                hdi->idProduct = le16toh(devinfo->product);
                hdi->idVersion = le16toh(devinfo->version);
                /* Save rdesc copy */
                rdesc = malloc(hdi->rdescsize, M_DEVBUF, M_WAITOK | M_ZERO);
                memcpy(rdesc, (const uint8_t *)hdesc + hdesc->bLength,
                    hdi->rdescsize);
                mtx_lock(&sc->mtx);
                sc->rdesc = rdesc;
                wakeup(sc);
                mtx_unlock(&sc->mtx);
                break;
        }
        case SH_INPUT_REPORT: {
                mtx_lock(&sc->mtx);
                if (sc->intr != NULL && sc->intr_on)
                        sc->intr(sc->intr_ctx,
                            __DECONST(void *, msg->irep.buffer),
                            msg->irep.hdr.size);
                mtx_unlock(&sc->mtx);
                break;
        }
        default:
                break;
        }
}

static void
hv_hid_read_channel(struct vmbus_channel *channel, void *ctx)
{
        hv_hid_sc       *sc;
        uint8_t         *buf;
        int             buflen;
        int             ret;

        sc = ctx;
        buf = sc->buf;
        buflen = sc->buflen;
        for (;;) {
                struct vmbus_chanpkt_hdr *pkt;
                int rcvd;

                pkt = (struct vmbus_chanpkt_hdr *)buf;
                rcvd = buflen;
                ret = vmbus_chan_recv_pkt(channel, pkt, &rcvd);
                if (__predict_false(ret == ENOBUFS)) {
                        buflen = sc->buflen * 2;
                        while (buflen < rcvd)
                                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 == 0, ("vmbus_chan_recv_pkt failed: %d", ret));

                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_hid_receive(sc, pkt);
                        break;
                default:
                        device_printf(sc->dev, "unknown event: %d\n",
                            pkt->cph_type);
                        break;
                }
        }
}

static int
hv_hid_probe(device_t dev)
{
        device_t                        bus;
        const struct vmbus_ic_desc      *d;

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

        bus = device_get_parent(dev);
        for (d = vmbus_hid_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 int
hv_hid_attach(device_t dev)
{
        device_t        child;
        hv_hid_sc       *sc;
        int             ret;

        sc = device_get_softc(dev);
        sc->dev = dev;
        mtx_init(&sc->mtx, "hvhid lock", NULL, MTX_DEF);
        sc->hs_chan = vmbus_get_channel(dev);
        sc->hs_xact_ctx = vmbus_xact_ctx_create(bus_get_dma_tag(dev),
            HV_HID_REQ_MAX, HV_HID_RESP_MAX, 0);
        if (sc->hs_xact_ctx == NULL) {
                ret = ENOMEM;
                goto out;
        }
        sc->buflen = HV_BUFSIZ;
        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_HID_RINGBUFF_SEND_SZ,
            HV_HID_RINGBUFF_RECV_SZ, NULL, 0, hv_hid_read_channel, sc);
        if (ret != 0)
                goto out;
        ret = hv_hid_connect_vsp(sc);
        if (ret != 0)
                goto out;

        /* Wait until we have devinfo (or arbitrary timeout of 3s) */
        mtx_lock(&sc->mtx);
        if (sc->rdesc == NULL)
                ret = mtx_sleep(sc, &sc->mtx, 0, "hvhid", hz * 3);
        mtx_unlock(&sc->mtx);
        if (ret != 0) {
                ret = ENODEV;
                goto out;
        }
        child = device_add_child(sc->dev, "hidbus", DEVICE_UNIT_ANY);
        if (child == NULL) {
                device_printf(sc->dev, "failed to add hidbus\n");
                ret = ENOMEM;
                goto out;
        }
        device_set_ivars(child, &sc->hdi);
        bus_attach_children(dev);
out:
        if (ret != 0)
                hv_hid_detach(dev);
        return (ret);
}

static int
hv_hid_detach(device_t dev)
{
        hv_hid_sc       *sc;
        int             ret;

        sc = device_get_softc(dev);
        ret = bus_generic_detach(dev);
        if (ret != 0)
                return (ret);
        if (sc->hs_xact_ctx != NULL)
                vmbus_xact_ctx_destroy(sc->hs_xact_ctx);
        vmbus_chan_close(vmbus_get_channel(dev));
        free(sc->buf, M_DEVBUF);
        free(sc->rdesc, M_DEVBUF);
        mtx_destroy(&sc->mtx);

        return (0);
}

static void
hv_hid_intr_setup(device_t dev, device_t child __unused, hid_intr_t intr,
    void *ctx, struct hid_rdesc_info *rdesc)
{
        hv_hid_sc       *sc;

        if (intr == NULL)
                return;

        sc = device_get_softc(dev);
        sc->intr = intr;
        sc->intr_on = false;
        sc->intr_ctx = ctx;
        rdesc->rdsize = rdesc->isize;
}

static void
hv_hid_intr_unsetup(device_t dev, device_t child __unused)
{
        hv_hid_sc       *sc;

        sc = device_get_softc(dev);
        sc->intr = NULL;
        sc->intr_on = false;
        sc->intr_ctx = NULL;
}

static int
hv_hid_intr_start(device_t dev, device_t child __unused)
{
        hv_hid_sc       *sc;

        sc = device_get_softc(dev);
        mtx_lock(&sc->mtx);
        sc->intr_on = true;
        mtx_unlock(&sc->mtx);
        return (0);
}

static int
hv_hid_intr_stop(device_t dev, device_t child __unused)
{
        hv_hid_sc       *sc;

        sc = device_get_softc(dev);
        mtx_lock(&sc->mtx);
        sc->intr_on = false;
        mtx_unlock(&sc->mtx);
        return (0);
}

static int
hv_hid_get_rdesc(device_t dev, device_t child __unused, void *buf,
    hid_size_t len)
{
        hv_hid_sc       *sc;

        sc = device_get_softc(dev);
        if (len < sc->hdi.rdescsize)
                return (EMSGSIZE);
        memcpy(buf, sc->rdesc, len);
        return (0);
}

static device_method_t hv_hid_methods[] = {
        DEVMETHOD(device_probe,         hv_hid_probe),
        DEVMETHOD(device_attach,        hv_hid_attach),
        DEVMETHOD(device_detach,        hv_hid_detach),

        DEVMETHOD(hid_intr_setup,       hv_hid_intr_setup),
        DEVMETHOD(hid_intr_unsetup,     hv_hid_intr_unsetup),
        DEVMETHOD(hid_intr_start,       hv_hid_intr_start),
        DEVMETHOD(hid_intr_stop,        hv_hid_intr_stop),

        DEVMETHOD(hid_get_rdesc,        hv_hid_get_rdesc),
        DEVMETHOD_END,
};

static driver_t hv_hid_driver = {
        .name = "hvhid",
        .methods = hv_hid_methods,
        .size = sizeof(hv_hid_sc),
};

DRIVER_MODULE(hv_hid, vmbus, hv_hid_driver, NULL, NULL);
MODULE_VERSION(hv_hid, 1);
MODULE_DEPEND(hv_hid, hidbus, 1, 1, 1);
MODULE_DEPEND(hv_hid, hms, 1, 1, 1);
MODULE_DEPEND(hv_hid, vmbus, 1, 1, 1);
MODULE_PNP_INFO("Z:classid", vmbus, hv_hid, vmbus_hid_descs_pnp,
    nitems(vmbus_hid_descs_pnp));