/*-
 * 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.
 */

/*
 * USB audio specs: http://www.usb.org/developers/devclass_docs/audio10.pdf
 *                  http://www.usb.org/developers/devclass_docs/frmts10.pdf
 *                  http://www.usb.org/developers/devclass_docs/termt10.pdf
 */

#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_audio_debug
#include <dev/usb/usb_debug.h>

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

enum {
        G_AUDIO_ISOC0_RD,
        G_AUDIO_ISOC1_RD,
        G_AUDIO_ISOC0_WR,
        G_AUDIO_ISOC1_WR,
        G_AUDIO_N_TRANSFER,
};

struct g_audio_softc {
        struct mtx sc_mtx;
        struct usb_callout sc_callout;
        struct usb_callout sc_watchdog;
        struct usb_xfer *sc_xfer[G_AUDIO_N_TRANSFER];

        int     sc_mode;
        int     sc_pattern_len;
        int     sc_throughput;
        int     sc_tx_interval;
        int     sc_state;
        int     sc_noise_rem;

        int8_t  sc_pattern[G_AUDIO_MAX_STRLEN];

        uint16_t sc_data_len[2][G_AUDIO_FRAMES];

        int16_t sc_data_buf[2][G_AUDIO_BUFSIZE / 2];

        uint8_t sc_volume_setting[32];
        uint8_t sc_volume_limit[32];
        uint8_t sc_sample_rate[32];
};

static SYSCTL_NODE(_hw_usb, OID_AUTO, g_audio, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
    "USB audio gadget");

#ifdef USB_DEBUG
static int g_audio_debug = 0;

SYSCTL_INT(_hw_usb_g_audio, OID_AUTO, debug, CTLFLAG_RWTUN,
    &g_audio_debug, 0, "Debug level");
#endif

static int g_audio_mode = 0;

SYSCTL_INT(_hw_usb_g_audio, OID_AUTO, mode, CTLFLAG_RWTUN,
    &g_audio_mode, 0, "Mode selection");

static int g_audio_pattern_interval = 1000;

SYSCTL_INT(_hw_usb_g_audio, OID_AUTO, pattern_interval, CTLFLAG_RWTUN,
    &g_audio_pattern_interval, 0, "Pattern interval in milliseconds");

static char g_audio_pattern_data[G_AUDIO_MAX_STRLEN];

SYSCTL_STRING(_hw_usb_g_audio, OID_AUTO, pattern, CTLFLAG_RW,
    &g_audio_pattern_data, sizeof(g_audio_pattern_data), "Data pattern");

static int g_audio_throughput;

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

static device_probe_t g_audio_probe;
static device_attach_t g_audio_attach;
static device_detach_t g_audio_detach;
static usb_handle_request_t g_audio_handle_request;

static usb_callback_t g_audio_isoc_read_callback;
static usb_callback_t g_audio_isoc_write_callback;

static void g_audio_watchdog(void *arg);
static void g_audio_timeout(void *arg);

static device_method_t g_audio_methods[] = {
        /* USB interface */
        DEVMETHOD(usb_handle_request, g_audio_handle_request),

        /* Device interface */
        DEVMETHOD(device_probe, g_audio_probe),
        DEVMETHOD(device_attach, g_audio_attach),
        DEVMETHOD(device_detach, g_audio_detach),

        DEVMETHOD_END
};

static driver_t g_audio_driver = {
        .name = "g_audio",
        .methods = g_audio_methods,
        .size = sizeof(struct g_audio_softc),
};

DRIVER_MODULE(g_audio, uhub, g_audio_driver, 0, 0);
MODULE_DEPEND(g_audio, usb, 1, 1, 1);

static const struct usb_config g_audio_config[G_AUDIO_N_TRANSFER] = {
        [G_AUDIO_ISOC0_RD] = {
                .type = UE_ISOCHRONOUS,
                .endpoint = UE_ADDR_ANY,
                .direction = UE_DIR_RX,
                .flags = {.ext_buffer = 1,.pipe_bof = 1,.short_xfer_ok = 1,},
                .bufsize = G_AUDIO_BUFSIZE,
                .callback = &g_audio_isoc_read_callback,
                .frames = G_AUDIO_FRAMES,
                .usb_mode = USB_MODE_DEVICE,
                .if_index = 1,
        },

        [G_AUDIO_ISOC1_RD] = {
                .type = UE_ISOCHRONOUS,
                .endpoint = UE_ADDR_ANY,
                .direction = UE_DIR_RX,
                .flags = {.ext_buffer = 1,.pipe_bof = 1,.short_xfer_ok = 1,},
                .bufsize = G_AUDIO_BUFSIZE,
                .callback = &g_audio_isoc_read_callback,
                .frames = G_AUDIO_FRAMES,
                .usb_mode = USB_MODE_DEVICE,
                .if_index = 1,
        },

        [G_AUDIO_ISOC0_WR] = {
                .type = UE_ISOCHRONOUS,
                .endpoint = UE_ADDR_ANY,
                .direction = UE_DIR_TX,
                .flags = {.ext_buffer = 1,.pipe_bof = 1,},
                .bufsize = G_AUDIO_BUFSIZE,
                .callback = &g_audio_isoc_write_callback,
                .frames = G_AUDIO_FRAMES,
                .usb_mode = USB_MODE_DEVICE,
                .if_index = 2,
        },

        [G_AUDIO_ISOC1_WR] = {
                .type = UE_ISOCHRONOUS,
                .endpoint = UE_ADDR_ANY,
                .direction = UE_DIR_TX,
                .flags = {.ext_buffer = 1,.pipe_bof = 1,},
                .bufsize = G_AUDIO_BUFSIZE,
                .callback = &g_audio_isoc_write_callback,
                .frames = G_AUDIO_FRAMES,
                .usb_mode = USB_MODE_DEVICE,
                .if_index = 2,
        },
};

static void
g_audio_timeout_reset(struct g_audio_softc *sc)
{
        int i = g_audio_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_audio_timeout, sc);
}

static void
g_audio_timeout(void *arg)
{
        struct g_audio_softc *sc = arg;

        sc->sc_mode = g_audio_mode;

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

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

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

        if (sc->sc_mode != G_AUDIO_MODE_LOOP) {
                usbd_transfer_start(sc->sc_xfer[G_AUDIO_ISOC0_WR]);
                usbd_transfer_start(sc->sc_xfer[G_AUDIO_ISOC1_WR]);
        }
        g_audio_timeout_reset(sc);
}

static void
g_audio_watchdog_reset(struct g_audio_softc *sc)
{
        usb_callout_reset(&sc->sc_watchdog, hz, &g_audio_watchdog, sc);
}

static void
g_audio_watchdog(void *arg)
{
        struct g_audio_softc *sc = arg;
        int i;

        i = sc->sc_throughput;

        sc->sc_throughput = 0;

        g_audio_throughput = i;

        g_audio_watchdog_reset(sc);
}

static int
g_audio_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_AUDIO) &&
            (uaa->info.bInterfaceSubClass == UISUBCLASS_AUDIOCONTROL))
                return (0);

        return (ENXIO);
}

static int
g_audio_attach(device_t dev)
{
        struct g_audio_softc *sc = device_get_softc(dev);
        struct usb_attach_arg *uaa = device_get_ivars(dev);
        int error;
        int i;
        uint8_t iface_index[3];

        DPRINTFN(11, "\n");

        device_set_usb_desc(dev);

        mtx_init(&sc->sc_mtx, "g_audio", 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_AUDIO_MODE_SILENT;

        sc->sc_noise_rem = 1;

        for (i = 0; i != G_AUDIO_FRAMES; i++) {
                sc->sc_data_len[0][i] = G_AUDIO_BUFSIZE / G_AUDIO_FRAMES;
                sc->sc_data_len[1][i] = G_AUDIO_BUFSIZE / G_AUDIO_FRAMES;
        }

        iface_index[0] = uaa->info.bIfaceIndex;
        iface_index[1] = uaa->info.bIfaceIndex + 1;
        iface_index[2] = uaa->info.bIfaceIndex + 2;

        error = usbd_set_alt_interface_index(uaa->device, iface_index[1], 1);
        if (error) {
                DPRINTF("alt iface setting error=%s\n", usbd_errstr(error));
                goto detach;
        }
        error = usbd_set_alt_interface_index(uaa->device, iface_index[2], 1);
        if (error) {
                DPRINTF("alt iface setting error=%s\n", usbd_errstr(error));
                goto detach;
        }
        error = usbd_transfer_setup(uaa->device,
            iface_index, sc->sc_xfer, g_audio_config,
            G_AUDIO_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]);
        usbd_set_parent_iface(uaa->device, iface_index[2], iface_index[0]);

        mtx_lock(&sc->sc_mtx);

        usbd_transfer_start(sc->sc_xfer[G_AUDIO_ISOC0_RD]);
        usbd_transfer_start(sc->sc_xfer[G_AUDIO_ISOC1_RD]);

        usbd_transfer_start(sc->sc_xfer[G_AUDIO_ISOC0_WR]);
        usbd_transfer_start(sc->sc_xfer[G_AUDIO_ISOC1_WR]);

        g_audio_timeout_reset(sc);

        g_audio_watchdog_reset(sc);

        mtx_unlock(&sc->sc_mtx);

        return (0);                     /* success */

detach:
        g_audio_detach(dev);

        return (ENXIO);                 /* error */
}

static int
g_audio_detach(device_t dev)
{
        struct g_audio_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_AUDIO_N_TRANSFER);

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

        mtx_destroy(&sc->sc_mtx);

        return (0);
}

static int32_t
g_noise(struct g_audio_softc *sc)
{
        uint32_t temp;
        const uint32_t prime = 0xFFFF1D;

        if (sc->sc_noise_rem & 1) {
                sc->sc_noise_rem += prime;
        }
        sc->sc_noise_rem /= 2;

        temp = sc->sc_noise_rem;

        /* unsigned to signed conversion */

        temp ^= 0x800000;
        if (temp & 0x800000) {
                temp |= (-0x800000);
        }
        return temp;
}

static void
g_audio_make_samples(struct g_audio_softc *sc, int16_t *ptr, int samples)
{
        int i;
        int j;

        for (i = 0; i != samples; i++) {
                j = g_noise(sc);

                if ((sc->sc_state < 0) || (sc->sc_state >= sc->sc_pattern_len))
                        sc->sc_state = 0;

                if (sc->sc_pattern_len != 0) {
                        j = (j * sc->sc_pattern[sc->sc_state]) >> 16;
                        sc->sc_state++;
                }
                *ptr++ = j / 256;
                *ptr++ = j / 256;
        }
}

static void
g_audio_isoc_write_callback(struct usb_xfer *xfer, usb_error_t error)
{
        struct g_audio_softc *sc = usbd_xfer_softc(xfer);
        int actlen;
        int aframes;
        int nr = (xfer == sc->sc_xfer[G_AUDIO_ISOC0_WR]) ? 0 : 1;
        int16_t *ptr;
        int i;

        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_AUDIO_MODE_LOOP)
                        break;          /* sync with RX */

        case USB_ST_SETUP:
tr_setup:

                ptr = sc->sc_data_buf[nr];

                if (sc->sc_mode == G_AUDIO_MODE_PATTERN) {
                        for (i = 0; i != G_AUDIO_FRAMES; i++) {
                                usbd_xfer_set_frame_data(xfer, i, ptr, sc->sc_data_len[nr][i]);

                                g_audio_make_samples(sc, ptr, (G_AUDIO_BUFSIZE / G_AUDIO_FRAMES) / 2);

                                ptr += (G_AUDIO_BUFSIZE / G_AUDIO_FRAMES) / 2;
                        }
                } else if (sc->sc_mode == G_AUDIO_MODE_LOOP) {
                        for (i = 0; i != G_AUDIO_FRAMES; i++) {
                                usbd_xfer_set_frame_data(xfer, i, ptr, sc->sc_data_len[nr][i] & ~3);

                                g_audio_make_samples(sc, ptr, sc->sc_data_len[nr][i] / 4);

                                ptr += (G_AUDIO_BUFSIZE / G_AUDIO_FRAMES) / 2;
                        }
                }
                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_audio_isoc_read_callback(struct usb_xfer *xfer, usb_error_t error)
{
        struct g_audio_softc *sc = usbd_xfer_softc(xfer);
        int actlen;
        int aframes;
        int nr = (xfer == sc->sc_xfer[G_AUDIO_ISOC0_RD]) ? 0 : 1;
        int16_t *ptr;
        int i;

        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;

                for (i = 0; i != G_AUDIO_FRAMES; i++) {
                        sc->sc_data_len[nr][i] = usbd_xfer_frame_len(xfer, i);
                }

                usbd_transfer_start(sc->sc_xfer[G_AUDIO_ISOC0_WR]);
                usbd_transfer_start(sc->sc_xfer[G_AUDIO_ISOC1_WR]);

                break;

        case USB_ST_SETUP:
tr_setup:
                ptr = sc->sc_data_buf[nr];

                for (i = 0; i != G_AUDIO_FRAMES; i++) {
                        usbd_xfer_set_frame_data(xfer, i, ptr,
                            G_AUDIO_BUFSIZE / G_AUDIO_FRAMES);

                        ptr += (G_AUDIO_BUFSIZE / G_AUDIO_FRAMES) / 2;
                }

                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_audio_handle_request(device_t dev,
    const void *preq, void **pptr, uint16_t *plen,
    uint16_t offset, uint8_t *pstate)
{
        struct g_audio_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_READ_CLASS_INTERFACE) &&
                    (req->bRequest == 0x82 /* get min */ )) {
                        if (offset == 0) {
                                USETW(sc->sc_volume_limit, 0);
                                *plen = 2;
                                *pptr = &sc->sc_volume_limit;
                        } else {
                                *plen = 0;
                        }
                        return (0);
                } else if ((req->bmRequestType == UT_READ_CLASS_INTERFACE) &&
                    (req->bRequest == 0x83 /* get max */ )) {
                        if (offset == 0) {
                                USETW(sc->sc_volume_limit, 0x2000);
                                *plen = 2;
                                *pptr = &sc->sc_volume_limit;
                        } else {
                                *plen = 0;
                        }
                        return (0);
                } else if ((req->bmRequestType == UT_READ_CLASS_INTERFACE) &&
                    (req->bRequest == 0x84 /* get residue */ )) {
                        if (offset == 0) {
                                USETW(sc->sc_volume_limit, 1);
                                *plen = 2;
                                *pptr = &sc->sc_volume_limit;
                        } else {
                                *plen = 0;
                        }
                        return (0);
                } else if ((req->bmRequestType == UT_READ_CLASS_INTERFACE) &&
                    (req->bRequest == 0x81 /* get value */ )) {
                        if (offset == 0) {
                                USETW(sc->sc_volume_setting, 0x2000);
                                *plen = sizeof(sc->sc_volume_setting);
                                *pptr = &sc->sc_volume_setting;
                        } else {
                                *plen = 0;
                        }
                        return (0);
                } else if ((req->bmRequestType == UT_WRITE_CLASS_INTERFACE) &&
                    (req->bRequest == 0x01 /* set value */ )) {
                        if (offset == 0) {
                                *plen = sizeof(sc->sc_volume_setting);
                                *pptr = &sc->sc_volume_setting;
                        } else {
                                *plen = 0;
                        }
                        return (0);
                } else if ((req->bmRequestType == UT_WRITE_CLASS_ENDPOINT) &&
                    (req->bRequest == 0x01 /* set value */ )) {
                        if (offset == 0) {
                                *plen = sizeof(sc->sc_sample_rate);
                                *pptr = &sc->sc_sample_rate;
                        } else {
                                *plen = 0;
                        }
                        return (0);
                }
        }
        return (ENXIO);                 /* use builtin handler */
}