text: /*-
   * 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>
  __FBSDID("$FreeBSD$");
  
  #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, 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 devclass_t g_audio_devclass;
  
  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, g_audio_devclass, 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 */
  }
  