/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2010 Hans Petter Selasky. 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.
 */

/*
 * Comm Class spec:  http://www.usb.org/developers/devclass_docs/usbccs10.pdf
 *                   http://www.usb.org/developers/devclass_docs/usbcdc11.pdf
 *                   http://www.usb.org/developers/devclass_docs/cdc_wmc10.zip
 */

#include <sys/param.h>
#include <sys/stdint.h>
#include <sys/stddef.h>
#include <sys/queue.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/bus.h>
#include <sys/linker_set.h>
#include <sys/module.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/condvar.h>
#include <sys/sysctl.h>
#include <sys/sx.h>
#include <sys/unistd.h>
#include <sys/callout.h>
#include <sys/malloc.h>
#include <sys/priv.h>

#include <dev/usb/usb.h>
#include <dev/usb/usb_cdc.h>
#include <dev/usb/usbdi.h>
#include <dev/usb/usbdi_util.h>
#include <dev/usb/usbhid.h>
#include "usb_if.h"

#define USB_DEBUG_VAR g_modem_debug
#include <dev/usb/usb_debug.h>

#include <dev/usb/gadget/g_modem.h>

enum {
        G_MODEM_INTR_DT,
        G_MODEM_BULK_RD,
        G_MODEM_BULK_WR,
        G_MODEM_N_TRANSFER,
};

struct g_modem_softc {
        struct mtx sc_mtx;
        struct usb_callout sc_callout;
        struct usb_callout sc_watchdog;
        struct usb_xfer *sc_xfer[G_MODEM_N_TRANSFER];

        int     sc_mode;
        int     sc_tx_busy;
        int     sc_pattern_len;
        int     sc_throughput;
        int     sc_tx_interval;

        char    sc_pattern[G_MODEM_MAX_STRLEN];

        uint16_t sc_data_len;

        uint8_t sc_data_buf[G_MODEM_BUFSIZE];
        uint8_t sc_line_coding[32];
        uint8_t sc_abstract_state[32];
};

static SYSCTL_NODE(_hw_usb, OID_AUTO, g_modem, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
    "USB modem gadget");

#ifdef USB_DEBUG
static int g_modem_debug = 0;

SYSCTL_INT(_hw_usb_g_modem, OID_AUTO, debug, CTLFLAG_RWTUN,
    &g_modem_debug, 0, "Debug level");
#endif

static int g_modem_mode = 0;

SYSCTL_INT(_hw_usb_g_modem, OID_AUTO, mode, CTLFLAG_RWTUN,
    &g_modem_mode, 0, "Mode selection");

static int g_modem_pattern_interval = 1000;

SYSCTL_INT(_hw_usb_g_modem, OID_AUTO, pattern_interval, CTLFLAG_RWTUN,
    &g_modem_pattern_interval, 0, "Pattern interval in milliseconds");

static char g_modem_pattern_data[G_MODEM_MAX_STRLEN];

SYSCTL_STRING(_hw_usb_g_modem, OID_AUTO, pattern, CTLFLAG_RW,
    &g_modem_pattern_data, sizeof(g_modem_pattern_data), "Data pattern");

static int g_modem_throughput;

SYSCTL_INT(_hw_usb_g_modem, OID_AUTO, throughput, CTLFLAG_RD,
    &g_modem_throughput, sizeof(g_modem_throughput), "Throughput in bytes per second");

static device_probe_t g_modem_probe;
static device_attach_t g_modem_attach;
static device_detach_t g_modem_detach;
static usb_handle_request_t g_modem_handle_request;
static usb_callback_t g_modem_intr_callback;
static usb_callback_t g_modem_bulk_read_callback;
static usb_callback_t g_modem_bulk_write_callback;

static void g_modem_timeout(void *arg);

static device_method_t g_modem_methods[] = {
        /* USB interface */
        DEVMETHOD(usb_handle_request, g_modem_handle_request),

        /* Device interface */
        DEVMETHOD(device_probe, g_modem_probe),
        DEVMETHOD(device_attach, g_modem_attach),
        DEVMETHOD(device_detach, g_modem_detach),

        DEVMETHOD_END
};

static driver_t g_modem_driver = {
        .name = "g_modem",
        .methods = g_modem_methods,
        .size = sizeof(struct g_modem_softc),
};

DRIVER_MODULE(g_modem, uhub, g_modem_driver, 0, 0);
MODULE_DEPEND(g_modem, usb, 1, 1, 1);

static const struct usb_config g_modem_config[G_MODEM_N_TRANSFER] = {
        [G_MODEM_INTR_DT] = {
                .type = UE_INTERRUPT,
                .endpoint = UE_ADDR_ANY,
                .direction = UE_DIR_TX,
                .flags = {.ext_buffer = 1,.pipe_bof = 1,},
                .bufsize = 0,   /* use wMaxPacketSize */
                .callback = &g_modem_intr_callback,
                .frames = 1,
                .usb_mode = USB_MODE_DEVICE,
                .if_index = 0,
        },

        [G_MODEM_BULK_RD] = {
                .type = UE_BULK,
                .endpoint = UE_ADDR_ANY,
                .direction = UE_DIR_RX,
                .flags = {.ext_buffer = 1,.pipe_bof = 1,.short_xfer_ok = 1,},
                .bufsize = G_MODEM_BUFSIZE,
                .callback = &g_modem_bulk_read_callback,
                .frames = 1,
                .usb_mode = USB_MODE_DEVICE,
                .if_index = 1,
        },

        [G_MODEM_BULK_WR] = {
                .type = UE_BULK,
                .endpoint = UE_ADDR_ANY,
                .direction = UE_DIR_TX,
                .flags = {.ext_buffer = 1,.pipe_bof = 1,},
                .bufsize = G_MODEM_BUFSIZE,
                .callback = &g_modem_bulk_write_callback,
                .frames = 1,
                .usb_mode = USB_MODE_DEVICE,
                .if_index = 1,
        },
};

static void
g_modem_timeout_reset(struct g_modem_softc *sc)
{
        int i = g_modem_pattern_interval;

        sc->sc_tx_interval = i;

        if (i <= 0)
                i = 1;
        else if (i > 1023)
                i = 1023;

        i = USB_MS_TO_TICKS(i);

        usb_callout_reset(&sc->sc_callout, i, &g_modem_timeout, sc);
}

static void
g_modem_timeout(void *arg)
{
        struct g_modem_softc *sc = arg;

        sc->sc_mode = g_modem_mode;

        memcpy(sc->sc_pattern, g_modem_pattern_data, sizeof(sc->sc_pattern));

        sc->sc_pattern[G_MODEM_MAX_STRLEN - 1] = 0;

        sc->sc_pattern_len = strlen(sc->sc_pattern);

        DPRINTFN(11, "Timeout %p\n", sc->sc_xfer[G_MODEM_INTR_DT]);

        usbd_transfer_start(sc->sc_xfer[G_MODEM_BULK_WR]);
        usbd_transfer_start(sc->sc_xfer[G_MODEM_BULK_RD]);

        g_modem_timeout_reset(sc);
}

static void g_modem_watchdog(void *arg);

static void
g_modem_watchdog_reset(struct g_modem_softc *sc)
{
        usb_callout_reset(&sc->sc_watchdog, hz, &g_modem_watchdog, sc);
}

static void
g_modem_watchdog(void *arg)
{
        struct g_modem_softc *sc = arg;
        int i;

        i = sc->sc_throughput;

        sc->sc_throughput = 0;

        g_modem_throughput = i;

        g_modem_watchdog_reset(sc);
}

static int
g_modem_probe(device_t dev)
{
        struct usb_attach_arg *uaa = device_get_ivars(dev);

        DPRINTFN(11, "\n");

        if (uaa->usb_mode != USB_MODE_DEVICE)
                return (ENXIO);

        if ((uaa->info.bInterfaceClass == UICLASS_CDC) &&
            (uaa->info.bInterfaceSubClass == UISUBCLASS_ABSTRACT_CONTROL_MODEL) &&
            (uaa->info.bInterfaceProtocol == UIPROTO_CDC_AT))
                return (0);

        return (ENXIO);
}

static int
g_modem_attach(device_t dev)
{
        struct g_modem_softc *sc = device_get_softc(dev);
        struct usb_attach_arg *uaa = device_get_ivars(dev);
        int error;
        uint8_t iface_index[2];

        DPRINTFN(11, "\n");

        device_set_usb_desc(dev);

        mtx_init(&sc->sc_mtx, "g_modem", NULL, MTX_DEF);

        usb_callout_init_mtx(&sc->sc_callout, &sc->sc_mtx, 0);
        usb_callout_init_mtx(&sc->sc_watchdog, &sc->sc_mtx, 0);

        sc->sc_mode = G_MODEM_MODE_SILENT;

        iface_index[0] = uaa->info.bIfaceIndex;
        iface_index[1] = uaa->info.bIfaceIndex + 1;

        error = usbd_transfer_setup(uaa->device,
            iface_index, sc->sc_xfer, g_modem_config,
            G_MODEM_N_TRANSFER, sc, &sc->sc_mtx);

        if (error) {
                DPRINTF("error=%s\n", usbd_errstr(error));
                goto detach;
        }
        usbd_set_parent_iface(uaa->device, iface_index[1], iface_index[0]);

        mtx_lock(&sc->sc_mtx);
        g_modem_timeout_reset(sc);
        g_modem_watchdog_reset(sc);
        mtx_unlock(&sc->sc_mtx);

        return (0);                     /* success */

detach:
        g_modem_detach(dev);

        return (ENXIO);                 /* error */
}

static int
g_modem_detach(device_t dev)
{
        struct g_modem_softc *sc = device_get_softc(dev);

        DPRINTF("\n");

        mtx_lock(&sc->sc_mtx);
        usb_callout_stop(&sc->sc_callout);
        usb_callout_stop(&sc->sc_watchdog);
        mtx_unlock(&sc->sc_mtx);

        usbd_transfer_unsetup(sc->sc_xfer, G_MODEM_N_TRANSFER);

        usb_callout_drain(&sc->sc_callout);
        usb_callout_drain(&sc->sc_watchdog);

        mtx_destroy(&sc->sc_mtx);

        return (0);
}

static void
g_modem_intr_callback(struct usb_xfer *xfer, usb_error_t error)
{
        int actlen;
        int aframes;

        usbd_xfer_status(xfer, &actlen, NULL, &aframes, NULL);

        DPRINTF("st=%d aframes=%d actlen=%d bytes\n",
            USB_GET_STATE(xfer), aframes, actlen);

        switch (USB_GET_STATE(xfer)) {
        case USB_ST_TRANSFERRED:
                break;

        case USB_ST_SETUP:
tr_setup:
                break;

        default:                        /* Error */
                DPRINTF("error=%s\n", usbd_errstr(error));

                if (error != USB_ERR_CANCELLED) {
                        /* try to clear stall first */
                        usbd_xfer_set_stall(xfer);
                        goto tr_setup;
                }
                break;
        }
}

static void
g_modem_bulk_write_callback(struct usb_xfer *xfer, usb_error_t error)
{
        struct g_modem_softc *sc = usbd_xfer_softc(xfer);
        int actlen;
        int aframes;
        int mod;
        int x;
        int max;

        usbd_xfer_status(xfer, &actlen, NULL, &aframes, NULL);

        DPRINTF("st=%d aframes=%d actlen=%d bytes\n",
            USB_GET_STATE(xfer), aframes, actlen);

        switch (USB_GET_STATE(xfer)) {
        case USB_ST_TRANSFERRED:

                sc->sc_tx_busy = 0;
                sc->sc_throughput += actlen;

                if (sc->sc_mode == G_MODEM_MODE_LOOP) {
                        /* start loop */
                        usbd_transfer_start(sc->sc_xfer[G_MODEM_BULK_RD]);
                        break;
                } else if ((sc->sc_mode == G_MODEM_MODE_PATTERN) && (sc->sc_tx_interval != 0)) {
                        /* wait for next timeout */
                        break;
                }
        case USB_ST_SETUP:
tr_setup:
                if (sc->sc_mode == G_MODEM_MODE_PATTERN) {
                        mod = sc->sc_pattern_len;
                        max = sc->sc_tx_interval ? mod : G_MODEM_BUFSIZE;

                        if (mod == 0) {
                                for (x = 0; x != max; x++)
                                        sc->sc_data_buf[x] = x % 255;
                        } else {
                                for (x = 0; x != max; x++)
                                        sc->sc_data_buf[x] = sc->sc_pattern[x % mod];
                        }

                        usbd_xfer_set_frame_data(xfer, 0, sc->sc_data_buf, max);
                        usbd_xfer_set_interval(xfer, 0);
                        usbd_xfer_set_frames(xfer, 1);
                        usbd_transfer_submit(xfer);

                } else if (sc->sc_mode == G_MODEM_MODE_LOOP) {
                        if (sc->sc_tx_busy == 0)
                                break;

                        x = sc->sc_tx_interval;

                        if (x < 0)
                                x = 0;
                        else if (x > 256)
                                x = 256;

                        usbd_xfer_set_frame_data(xfer, 0, sc->sc_data_buf, sc->sc_data_len);
                        usbd_xfer_set_interval(xfer, x);
                        usbd_xfer_set_frames(xfer, 1);
                        usbd_transfer_submit(xfer);
                } else {
                        sc->sc_tx_busy = 0;
                }
                break;

        default:                        /* Error */
                DPRINTF("error=%s\n", usbd_errstr(error));

                if (error != USB_ERR_CANCELLED) {
                        /* try to clear stall first */
                        usbd_xfer_set_stall(xfer);
                        goto tr_setup;
                }
                break;
        }
}

static void
g_modem_bulk_read_callback(struct usb_xfer *xfer, usb_error_t error)
{
        struct g_modem_softc *sc = usbd_xfer_softc(xfer);
        int actlen;
        int aframes;

        usbd_xfer_status(xfer, &actlen, NULL, &aframes, NULL);

        DPRINTF("st=%d aframes=%d actlen=%d bytes\n",
            USB_GET_STATE(xfer), aframes, actlen);

        switch (USB_GET_STATE(xfer)) {
        case USB_ST_TRANSFERRED:

                sc->sc_throughput += actlen;

                if (sc->sc_mode == G_MODEM_MODE_LOOP) {
                        sc->sc_tx_busy = 1;
                        sc->sc_data_len = actlen;
                        usbd_transfer_start(sc->sc_xfer[G_MODEM_BULK_WR]);
                        break;
                }

        case USB_ST_SETUP:
tr_setup:
                if ((sc->sc_mode == G_MODEM_MODE_SILENT) ||
                    (sc->sc_tx_busy != 0))
                        break;

                usbd_xfer_set_frame_data(xfer, 0, sc->sc_data_buf, G_MODEM_BUFSIZE);
                usbd_xfer_set_frames(xfer, 1);
                usbd_transfer_submit(xfer);
                break;

        default:                        /* Error */
                DPRINTF("error=%s\n", usbd_errstr(error));

                if (error != USB_ERR_CANCELLED) {
                        /* try to clear stall first */
                        usbd_xfer_set_stall(xfer);
                        goto tr_setup;
                }
                break;
        }
}

static int
g_modem_handle_request(device_t dev,
    const void *preq, void **pptr, uint16_t *plen,
    uint16_t offset, uint8_t *pstate)
{
        struct g_modem_softc *sc = device_get_softc(dev);
        const struct usb_device_request *req = preq;
        uint8_t is_complete = *pstate;

        if (!is_complete) {
                if ((req->bmRequestType == UT_WRITE_CLASS_INTERFACE) &&
                    (req->bRequest == UCDC_SET_LINE_CODING) &&
                    (req->wValue[0] == 0x00) &&
                    (req->wValue[1] == 0x00)) {
                        if (offset == 0) {
                                *plen = sizeof(sc->sc_line_coding);
                                *pptr = &sc->sc_line_coding;
                        } else {
                                *plen = 0;
                        }
                        return (0);
                } else if ((req->bmRequestType == UT_WRITE_CLASS_INTERFACE) &&
                    (req->bRequest == UCDC_SET_COMM_FEATURE)) {
                        if (offset == 0) {
                                *plen = sizeof(sc->sc_abstract_state);
                                *pptr = &sc->sc_abstract_state;
                        } else {
                                *plen = 0;
                        }
                        return (0);
                } else if ((req->bmRequestType == UT_WRITE_CLASS_INTERFACE) &&
                    (req->bRequest == UCDC_SET_CONTROL_LINE_STATE)) {
                        *plen = 0;
                        return (0);
                } else if ((req->bmRequestType == UT_WRITE_CLASS_INTERFACE) &&
                    (req->bRequest == UCDC_SEND_BREAK)) {
                        *plen = 0;
                        return (0);
                }
        }
        return (ENXIO);                 /* use builtin handler */
}