Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1408 insertions, 0 deletions

diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c
new file mode 100644
index 000000000..fddf53900
--- /dev/null
+++ b/drivers/usb/gadget/function/f_midi.c
@@ -0,0 +1,1408 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * f_midi.c -- USB MIDI class function driver
+ *
+ * Copyright (C) 2006 Thumtronics Pty Ltd.
+ * Developed for Thumtronics by Grey Innovation
+ * Ben Williamson <ben.williamson@greyinnovation.com>
+ *
+ * Rewritten for the composite framework
+ *   Copyright (C) 2011 Daniel Mack <zonque@gmail.com>
+ *
+ * Based on drivers/usb/gadget/f_audio.c,
+ *   Copyright (C) 2008 Bryan Wu <cooloney@kernel.org>
+ *   Copyright (C) 2008 Analog Devices, Inc
+ *
+ * and drivers/usb/gadget/midi.c,
+ *   Copyright (C) 2006 Thumtronics Pty Ltd.
+ *   Ben Williamson <ben.williamson@greyinnovation.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/device.h>
+#include <linux/kfifo.h>
+#include <linux/spinlock.h>
+
+#include <sound/core.h>
+#include <sound/initval.h>
+#include <sound/rawmidi.h>
+
+#include <linux/usb/ch9.h>
+#include <linux/usb/gadget.h>
+#include <linux/usb/audio.h>
+#include <linux/usb/midi.h>
+
+#include "u_f.h"
+#include "u_midi.h"
+
+MODULE_AUTHOR("Ben Williamson");
+MODULE_LICENSE("GPL v2");
+
+static const char f_midi_shortname[] = "f_midi";
+static const char f_midi_longname[] = "MIDI Gadget";
+
+/*
+ * We can only handle 16 cables on one single endpoint, as cable numbers are
+ * stored in 4-bit fields. And as the interface currently only holds one
+ * single endpoint, this is the maximum number of ports we can allow.
+ */
+#define MAX_PORTS 16
+
+/* MIDI message states */
+enum {
+	STATE_INITIAL = 0,	/* pseudo state */
+	STATE_1PARAM,
+	STATE_2PARAM_1,
+	STATE_2PARAM_2,
+	STATE_SYSEX_0,
+	STATE_SYSEX_1,
+	STATE_SYSEX_2,
+	STATE_REAL_TIME,
+	STATE_FINISHED,		/* pseudo state */
+};
+
+/*
+ * This is a gadget, and the IN/OUT naming is from the host's perspective.
+ * USB -> OUT endpoint -> rawmidi
+ * USB <- IN endpoint  <- rawmidi
+ */
+struct gmidi_in_port {
+	struct snd_rawmidi_substream *substream;
+	int active;
+	uint8_t cable;
+	uint8_t state;
+	uint8_t data[2];
+};
+
+struct f_midi {
+	struct usb_function	func;
+	struct usb_gadget	*gadget;
+	struct usb_ep		*in_ep, *out_ep;
+	struct snd_card		*card;
+	struct snd_rawmidi	*rmidi;
+	u8			ms_id;
+
+	struct snd_rawmidi_substream *out_substream[MAX_PORTS];
+
+	unsigned long		out_triggered;
+	struct work_struct	work;
+	unsigned int in_ports;
+	unsigned int out_ports;
+	int index;
+	char *id;
+	unsigned int buflen, qlen;
+	/* This fifo is used as a buffer ring for pre-allocated IN usb_requests */
+	DECLARE_KFIFO_PTR(in_req_fifo, struct usb_request *);
+	spinlock_t transmit_lock;
+	unsigned int in_last_port;
+	unsigned char free_ref;
+
+	struct gmidi_in_port	in_ports_array[/* in_ports */];
+};
+
+static inline struct f_midi *func_to_midi(struct usb_function *f)
+{
+	return container_of(f, struct f_midi, func);
+}
+
+static void f_midi_transmit(struct f_midi *midi);
+static void f_midi_rmidi_free(struct snd_rawmidi *rmidi);
+static void f_midi_free_inst(struct usb_function_instance *f);
+
+DECLARE_UAC_AC_HEADER_DESCRIPTOR(1);
+DECLARE_USB_MIDI_OUT_JACK_DESCRIPTOR(1);
+DECLARE_USB_MS_ENDPOINT_DESCRIPTOR(16);
+
+/* B.3.1  Standard AC Interface Descriptor */
+static struct usb_interface_descriptor ac_interface_desc = {
+	.bLength =		USB_DT_INTERFACE_SIZE,
+	.bDescriptorType =	USB_DT_INTERFACE,
+	/* .bInterfaceNumber =	DYNAMIC */
+	/* .bNumEndpoints =	DYNAMIC */
+	.bInterfaceClass =	USB_CLASS_AUDIO,
+	.bInterfaceSubClass =	USB_SUBCLASS_AUDIOCONTROL,
+	/* .iInterface =	DYNAMIC */
+};
+
+/* B.3.2  Class-Specific AC Interface Descriptor */
+static struct uac1_ac_header_descriptor_1 ac_header_desc = {
+	.bLength =		UAC_DT_AC_HEADER_SIZE(1),
+	.bDescriptorType =	USB_DT_CS_INTERFACE,
+	.bDescriptorSubtype =	USB_MS_HEADER,
+	.bcdADC =		cpu_to_le16(0x0100),
+	.wTotalLength =		cpu_to_le16(UAC_DT_AC_HEADER_SIZE(1)),
+	.bInCollection =	1,
+	/* .baInterfaceNr =	DYNAMIC */
+};
+
+/* B.4.1  Standard MS Interface Descriptor */
+static struct usb_interface_descriptor ms_interface_desc = {
+	.bLength =		USB_DT_INTERFACE_SIZE,
+	.bDescriptorType =	USB_DT_INTERFACE,
+	/* .bInterfaceNumber =	DYNAMIC */
+	.bNumEndpoints =	2,
+	.bInterfaceClass =	USB_CLASS_AUDIO,
+	.bInterfaceSubClass =	USB_SUBCLASS_MIDISTREAMING,
+	/* .iInterface =	DYNAMIC */
+};
+
+/* B.4.2  Class-Specific MS Interface Descriptor */
+static struct usb_ms_header_descriptor ms_header_desc = {
+	.bLength =		USB_DT_MS_HEADER_SIZE,
+	.bDescriptorType =	USB_DT_CS_INTERFACE,
+	.bDescriptorSubtype =	USB_MS_HEADER,
+	.bcdMSC =		cpu_to_le16(0x0100),
+	/* .wTotalLength =	DYNAMIC */
+};
+
+/* B.5.1  Standard Bulk OUT Endpoint Descriptor */
+static struct usb_endpoint_descriptor bulk_out_desc = {
+	.bLength =		USB_DT_ENDPOINT_AUDIO_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+	.bEndpointAddress =	USB_DIR_OUT,
+	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
+};
+
+static struct usb_ss_ep_comp_descriptor bulk_out_ss_comp_desc = {
+	.bLength                = sizeof(bulk_out_ss_comp_desc),
+	.bDescriptorType        = USB_DT_SS_ENDPOINT_COMP,
+	/* .bMaxBurst           = 0, */
+	/* .bmAttributes        = 0, */
+};
+
+/* B.5.2  Class-specific MS Bulk OUT Endpoint Descriptor */
+static struct usb_ms_endpoint_descriptor_16 ms_out_desc = {
+	/* .bLength =		DYNAMIC */
+	.bDescriptorType =	USB_DT_CS_ENDPOINT,
+	.bDescriptorSubtype =	USB_MS_GENERAL,
+	/* .bNumEmbMIDIJack =	DYNAMIC */
+	/* .baAssocJackID =	DYNAMIC */
+};
+
+/* B.6.1  Standard Bulk IN Endpoint Descriptor */
+static struct usb_endpoint_descriptor bulk_in_desc = {
+	.bLength =		USB_DT_ENDPOINT_AUDIO_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+	.bEndpointAddress =	USB_DIR_IN,
+	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
+};
+
+static struct usb_ss_ep_comp_descriptor bulk_in_ss_comp_desc = {
+	.bLength                = sizeof(bulk_in_ss_comp_desc),
+	.bDescriptorType        = USB_DT_SS_ENDPOINT_COMP,
+	/* .bMaxBurst           = 0, */
+	/* .bmAttributes        = 0, */
+};
+
+/* B.6.2  Class-specific MS Bulk IN Endpoint Descriptor */
+static struct usb_ms_endpoint_descriptor_16 ms_in_desc = {
+	/* .bLength =		DYNAMIC */
+	.bDescriptorType =	USB_DT_CS_ENDPOINT,
+	.bDescriptorSubtype =	USB_MS_GENERAL,
+	/* .bNumEmbMIDIJack =	DYNAMIC */
+	/* .baAssocJackID =	DYNAMIC */
+};
+
+/* string IDs are assigned dynamically */
+
+#define STRING_FUNC_IDX			0
+
+static struct usb_string midi_string_defs[] = {
+	[STRING_FUNC_IDX].s = "MIDI function",
+	{  } /* end of list */
+};
+
+static struct usb_gadget_strings midi_stringtab = {
+	.language	= 0x0409,	/* en-us */
+	.strings	= midi_string_defs,
+};
+
+static struct usb_gadget_strings *midi_strings[] = {
+	&midi_stringtab,
+	NULL,
+};
+
+static inline struct usb_request *midi_alloc_ep_req(struct usb_ep *ep,
+						    unsigned length)
+{
+	return alloc_ep_req(ep, length);
+}
+
+static const uint8_t f_midi_cin_length[] = {
+	0, 0, 2, 3, 3, 1, 2, 3, 3, 3, 3, 3, 2, 2, 3, 1
+};
+
+/*
+ * Receives a chunk of MIDI data.
+ */
+static void f_midi_read_data(struct usb_ep *ep, int cable,
+			     uint8_t *data, int length)
+{
+	struct f_midi *midi = ep->driver_data;
+	struct snd_rawmidi_substream *substream = midi->out_substream[cable];
+
+	if (!substream)
+		/* Nobody is listening - throw it on the floor. */
+		return;
+
+	if (!test_bit(cable, &midi->out_triggered))
+		return;
+
+	snd_rawmidi_receive(substream, data, length);
+}
+
+static void f_midi_handle_out_data(struct usb_ep *ep, struct usb_request *req)
+{
+	unsigned int i;
+	u8 *buf = req->buf;
+
+	for (i = 0; i + 3 < req->actual; i += 4)
+		if (buf[i] != 0) {
+			int cable = buf[i] >> 4;
+			int length = f_midi_cin_length[buf[i] & 0x0f];
+			f_midi_read_data(ep, cable, &buf[i + 1], length);
+		}
+}
+
+static void
+f_midi_complete(struct usb_ep *ep, struct usb_request *req)
+{
+	struct f_midi *midi = ep->driver_data;
+	struct usb_composite_dev *cdev = midi->func.config->cdev;
+	int status = req->status;
+
+	switch (status) {
+	case 0:			 /* normal completion */
+		if (ep == midi->out_ep) {
+			/* We received stuff. req is queued again, below */
+			f_midi_handle_out_data(ep, req);
+		} else if (ep == midi->in_ep) {
+			/* Our transmit completed. See if there's more to go.
+			 * f_midi_transmit eats req, don't queue it again. */
+			req->length = 0;
+			f_midi_transmit(midi);
+			return;
+		}
+		break;
+
+	/* this endpoint is normally active while we're configured */
+	case -ECONNABORTED:	/* hardware forced ep reset */
+	case -ECONNRESET:	/* request dequeued */
+	case -ESHUTDOWN:	/* disconnect from host */
+		VDBG(cdev, "%s gone (%d), %d/%d\n", ep->name, status,
+				req->actual, req->length);
+		if (ep == midi->out_ep) {
+			f_midi_handle_out_data(ep, req);
+			/* We don't need to free IN requests because it's handled
+			 * by the midi->in_req_fifo. */
+			free_ep_req(ep, req);
+		}
+		return;
+
+	case -EOVERFLOW:	/* buffer overrun on read means that
+				 * we didn't provide a big enough buffer.
+				 */
+	default:
+		DBG(cdev, "%s complete --> %d, %d/%d\n", ep->name,
+				status, req->actual, req->length);
+		break;
+	case -EREMOTEIO:	/* short read */
+		break;
+	}
+
+	status = usb_ep_queue(ep, req, GFP_ATOMIC);
+	if (status) {
+		ERROR(cdev, "kill %s:  resubmit %d bytes --> %d\n",
+				ep->name, req->length, status);
+		usb_ep_set_halt(ep);
+		/* FIXME recover later ... somehow */
+	}
+}
+
+static void f_midi_drop_out_substreams(struct f_midi *midi)
+{
+	unsigned int i;
+
+	for (i = 0; i < midi->in_ports; i++) {
+		struct gmidi_in_port *port = midi->in_ports_array + i;
+		struct snd_rawmidi_substream *substream = port->substream;
+
+		if (port->active && substream)
+			snd_rawmidi_drop_output(substream);
+	}
+}
+
+static int f_midi_start_ep(struct f_midi *midi,
+			   struct usb_function *f,
+			   struct usb_ep *ep)
+{
+	int err;
+	struct usb_composite_dev *cdev = f->config->cdev;
+
+	usb_ep_disable(ep);
+
+	err = config_ep_by_speed(midi->gadget, f, ep);
+	if (err) {
+		ERROR(cdev, "can't configure %s: %d\n", ep->name, err);
+		return err;
+	}
+
+	err = usb_ep_enable(ep);
+	if (err) {
+		ERROR(cdev, "can't start %s: %d\n", ep->name, err);
+		return err;
+	}
+
+	ep->driver_data = midi;
+
+	return 0;
+}
+
+static int f_midi_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
+{
+	struct f_midi *midi = func_to_midi(f);
+	unsigned i;
+	int err;
+
+	/* we only set alt for MIDIStreaming interface */
+	if (intf != midi->ms_id)
+		return 0;
+
+	err = f_midi_start_ep(midi, f, midi->in_ep);
+	if (err)
+		return err;
+
+	err = f_midi_start_ep(midi, f, midi->out_ep);
+	if (err)
+		return err;
+
+	/* pre-allocate write usb requests to use on f_midi_transmit. */
+	while (kfifo_avail(&midi->in_req_fifo)) {
+		struct usb_request *req =
+			midi_alloc_ep_req(midi->in_ep, midi->buflen);
+
+		if (req == NULL)
+			return -ENOMEM;
+
+		req->length = 0;
+		req->complete = f_midi_complete;
+
+		kfifo_put(&midi->in_req_fifo, req);
+	}
+
+	/* allocate a bunch of read buffers and queue them all at once. */
+	for (i = 0; i < midi->qlen && err == 0; i++) {
+		struct usb_request *req =
+			midi_alloc_ep_req(midi->out_ep, midi->buflen);
+
+		if (req == NULL)
+			return -ENOMEM;
+
+		req->complete = f_midi_complete;
+		err = usb_ep_queue(midi->out_ep, req, GFP_ATOMIC);
+		if (err) {
+			ERROR(midi, "%s: couldn't enqueue request: %d\n",
+				    midi->out_ep->name, err);
+			if (req->buf != NULL)
+				free_ep_req(midi->out_ep, req);
+			return err;
+		}
+	}
+
+	return 0;
+}
+
+static void f_midi_disable(struct usb_function *f)
+{
+	struct f_midi *midi = func_to_midi(f);
+	struct usb_composite_dev *cdev = f->config->cdev;
+	struct usb_request *req = NULL;
+
+	DBG(cdev, "disable\n");
+
+	/*
+	 * just disable endpoints, forcing completion of pending i/o.
+	 * all our completion handlers free their requests in this case.
+	 */
+	usb_ep_disable(midi->in_ep);
+	usb_ep_disable(midi->out_ep);
+
+	/* release IN requests */
+	while (kfifo_get(&midi->in_req_fifo, &req))
+		free_ep_req(midi->in_ep, req);
+
+	f_midi_drop_out_substreams(midi);
+}
+
+static int f_midi_snd_free(struct snd_device *device)
+{
+	return 0;
+}
+
+/*
+ * Converts MIDI commands to USB MIDI packets.
+ */
+static void f_midi_transmit_byte(struct usb_request *req,
+				 struct gmidi_in_port *port, uint8_t b)
+{
+	uint8_t p[4] = { port->cable << 4, 0, 0, 0 };
+	uint8_t next_state = STATE_INITIAL;
+
+	switch (b) {
+	case 0xf8 ... 0xff:
+		/* System Real-Time Messages */
+		p[0] |= 0x0f;
+		p[1] = b;
+		next_state = port->state;
+		port->state = STATE_REAL_TIME;
+		break;
+
+	case 0xf7:
+		/* End of SysEx */
+		switch (port->state) {
+		case STATE_SYSEX_0:
+			p[0] |= 0x05;
+			p[1] = 0xf7;
+			next_state = STATE_FINISHED;
+			break;
+		case STATE_SYSEX_1:
+			p[0] |= 0x06;
+			p[1] = port->data[0];
+			p[2] = 0xf7;
+			next_state = STATE_FINISHED;
+			break;
+		case STATE_SYSEX_2:
+			p[0] |= 0x07;
+			p[1] = port->data[0];
+			p[2] = port->data[1];
+			p[3] = 0xf7;
+			next_state = STATE_FINISHED;
+			break;
+		default:
+			/* Ignore byte */
+			next_state = port->state;
+			port->state = STATE_INITIAL;
+		}
+		break;
+
+	case 0xf0 ... 0xf6:
+		/* System Common Messages */
+		port->data[0] = port->data[1] = 0;
+		port->state = STATE_INITIAL;
+		switch (b) {
+		case 0xf0:
+			port->data[0] = b;
+			port->data[1] = 0;
+			next_state = STATE_SYSEX_1;
+			break;
+		case 0xf1:
+		case 0xf3:
+			port->data[0] = b;
+			next_state = STATE_1PARAM;
+			break;
+		case 0xf2:
+			port->data[0] = b;
+			next_state = STATE_2PARAM_1;
+			break;
+		case 0xf4:
+		case 0xf5:
+			next_state = STATE_INITIAL;
+			break;
+		case 0xf6:
+			p[0] |= 0x05;
+			p[1] = 0xf6;
+			next_state = STATE_FINISHED;
+			break;
+		}
+		break;
+
+	case 0x80 ... 0xef:
+		/*
+		 * Channel Voice Messages, Channel Mode Messages
+		 * and Control Change Messages.
+		 */
+		port->data[0] = b;
+		port->data[1] = 0;
+		port->state = STATE_INITIAL;
+		if (b >= 0xc0 && b <= 0xdf)
+			next_state = STATE_1PARAM;
+		else
+			next_state = STATE_2PARAM_1;
+		break;
+
+	case 0x00 ... 0x7f:
+		/* Message parameters */
+		switch (port->state) {
+		case STATE_1PARAM:
+			if (port->data[0] < 0xf0)
+				p[0] |= port->data[0] >> 4;
+			else
+				p[0] |= 0x02;
+
+			p[1] = port->data[0];
+			p[2] = b;
+			/* This is to allow Running State Messages */
+			next_state = STATE_1PARAM;
+			break;
+		case STATE_2PARAM_1:
+			port->data[1] = b;
+			next_state = STATE_2PARAM_2;
+			break;
+		case STATE_2PARAM_2:
+			if (port->data[0] < 0xf0)
+				p[0] |= port->data[0] >> 4;
+			else
+				p[0] |= 0x03;
+
+			p[1] = port->data[0];
+			p[2] = port->data[1];
+			p[3] = b;
+			/* This is to allow Running State Messages */
+			next_state = STATE_2PARAM_1;
+			break;
+		case STATE_SYSEX_0:
+			port->data[0] = b;
+			next_state = STATE_SYSEX_1;
+			break;
+		case STATE_SYSEX_1:
+			port->data[1] = b;
+			next_state = STATE_SYSEX_2;
+			break;
+		case STATE_SYSEX_2:
+			p[0] |= 0x04;
+			p[1] = port->data[0];
+			p[2] = port->data[1];
+			p[3] = b;
+			next_state = STATE_SYSEX_0;
+			break;
+		}
+		break;
+	}
+
+	/* States where we have to write into the USB request */
+	if (next_state == STATE_FINISHED ||
+	    port->state == STATE_SYSEX_2 ||
+	    port->state == STATE_1PARAM ||
+	    port->state == STATE_2PARAM_2 ||
+	    port->state == STATE_REAL_TIME) {
+
+		unsigned int length = req->length;
+		u8 *buf = (u8 *)req->buf + length;
+
+		memcpy(buf, p, sizeof(p));
+		req->length = length + sizeof(p);
+
+		if (next_state == STATE_FINISHED) {
+			next_state = STATE_INITIAL;
+			port->data[0] = port->data[1] = 0;
+		}
+	}
+
+	port->state = next_state;
+}
+
+static int f_midi_do_transmit(struct f_midi *midi, struct usb_ep *ep)
+{
+	struct usb_request *req = NULL;
+	unsigned int len, i;
+	bool active = false;
+	int err;
+
+	/*
+	 * We peek the request in order to reuse it if it fails to enqueue on
+	 * its endpoint
+	 */
+	len = kfifo_peek(&midi->in_req_fifo, &req);
+	if (len != 1) {
+		ERROR(midi, "%s: Couldn't get usb request\n", __func__);
+		return -1;
+	}
+
+	/*
+	 * If buffer overrun, then we ignore this transmission.
+	 * IMPORTANT: This will cause the user-space rawmidi device to block
+	 * until a) usb requests have been completed or b) snd_rawmidi_write()
+	 * times out.
+	 */
+	if (req->length > 0)
+		return 0;
+
+	for (i = midi->in_last_port; i < midi->in_ports; ++i) {
+		struct gmidi_in_port *port = midi->in_ports_array + i;
+		struct snd_rawmidi_substream *substream = port->substream;
+
+		if (!port->active || !substream)
+			continue;
+
+		while (req->length + 3 < midi->buflen) {
+			uint8_t b;
+
+			if (snd_rawmidi_transmit(substream, &b, 1) != 1) {
+				port->active = 0;
+				break;
+			}
+			f_midi_transmit_byte(req, port, b);
+		}
+
+		active = !!port->active;
+		if (active)
+			break;
+	}
+	midi->in_last_port = active ? i : 0;
+
+	if (req->length <= 0)
+		goto done;
+
+	err = usb_ep_queue(ep, req, GFP_ATOMIC);
+	if (err < 0) {
+		ERROR(midi, "%s failed to queue req: %d\n",
+		      midi->in_ep->name, err);
+		req->length = 0; /* Re-use request next time. */
+	} else {
+		/* Upon success, put request at the back of the queue. */
+		kfifo_skip(&midi->in_req_fifo);
+		kfifo_put(&midi->in_req_fifo, req);
+	}
+
+done:
+	return active;
+}
+
+static void f_midi_transmit(struct f_midi *midi)
+{
+	struct usb_ep *ep = midi->in_ep;
+	int ret;
+	unsigned long flags;
+
+	/* We only care about USB requests if IN endpoint is enabled */
+	if (!ep || !ep->enabled)
+		goto drop_out;
+
+	spin_lock_irqsave(&midi->transmit_lock, flags);
+
+	do {
+		ret = f_midi_do_transmit(midi, ep);
+		if (ret < 0) {
+			spin_unlock_irqrestore(&midi->transmit_lock, flags);
+			goto drop_out;
+		}
+	} while (ret);
+
+	spin_unlock_irqrestore(&midi->transmit_lock, flags);
+
+	return;
+
+drop_out:
+	f_midi_drop_out_substreams(midi);
+}
+
+static void f_midi_in_work(struct work_struct *work)
+{
+	struct f_midi *midi;
+
+	midi = container_of(work, struct f_midi, work);
+	f_midi_transmit(midi);
+}
+
+static int f_midi_in_open(struct snd_rawmidi_substream *substream)
+{
+	struct f_midi *midi = substream->rmidi->private_data;
+	struct gmidi_in_port *port;
+
+	if (substream->number >= midi->in_ports)
+		return -EINVAL;
+
+	VDBG(midi, "%s()\n", __func__);
+	port = midi->in_ports_array + substream->number;
+	port->substream = substream;
+	port->state = STATE_INITIAL;
+	return 0;
+}
+
+static int f_midi_in_close(struct snd_rawmidi_substream *substream)
+{
+	struct f_midi *midi = substream->rmidi->private_data;
+
+	VDBG(midi, "%s()\n", __func__);
+	return 0;
+}
+
+static void f_midi_in_trigger(struct snd_rawmidi_substream *substream, int up)
+{
+	struct f_midi *midi = substream->rmidi->private_data;
+
+	if (substream->number >= midi->in_ports)
+		return;
+
+	VDBG(midi, "%s() %d\n", __func__, up);
+	midi->in_ports_array[substream->number].active = up;
+	if (up)
+		queue_work(system_highpri_wq, &midi->work);
+}
+
+static int f_midi_out_open(struct snd_rawmidi_substream *substream)
+{
+	struct f_midi *midi = substream->rmidi->private_data;
+
+	if (substream->number >= MAX_PORTS)
+		return -EINVAL;
+
+	VDBG(midi, "%s()\n", __func__);
+	midi->out_substream[substream->number] = substream;
+	return 0;
+}
+
+static int f_midi_out_close(struct snd_rawmidi_substream *substream)
+{
+	struct f_midi *midi = substream->rmidi->private_data;
+
+	VDBG(midi, "%s()\n", __func__);
+	return 0;
+}
+
+static void f_midi_out_trigger(struct snd_rawmidi_substream *substream, int up)
+{
+	struct f_midi *midi = substream->rmidi->private_data;
+
+	VDBG(midi, "%s()\n", __func__);
+
+	if (up)
+		set_bit(substream->number, &midi->out_triggered);
+	else
+		clear_bit(substream->number, &midi->out_triggered);
+}
+
+static const struct snd_rawmidi_ops gmidi_in_ops = {
+	.open = f_midi_in_open,
+	.close = f_midi_in_close,
+	.trigger = f_midi_in_trigger,
+};
+
+static const struct snd_rawmidi_ops gmidi_out_ops = {
+	.open = f_midi_out_open,
+	.close = f_midi_out_close,
+	.trigger = f_midi_out_trigger
+};
+
+static inline void f_midi_unregister_card(struct f_midi *midi)
+{
+	if (midi->card) {
+		snd_card_free(midi->card);
+		midi->card = NULL;
+	}
+}
+
+/* register as a sound "card" */
+static int f_midi_register_card(struct f_midi *midi)
+{
+	struct snd_card *card;
+	struct snd_rawmidi *rmidi;
+	int err;
+	static struct snd_device_ops ops = {
+		.dev_free = f_midi_snd_free,
+	};
+
+	err = snd_card_new(&midi->gadget->dev, midi->index, midi->id,
+			   THIS_MODULE, 0, &card);
+	if (err < 0) {
+		ERROR(midi, "snd_card_new() failed\n");
+		goto fail;
+	}
+	midi->card = card;
+
+	err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, midi, &ops);
+	if (err < 0) {
+		ERROR(midi, "snd_device_new() failed: error %d\n", err);
+		goto fail;
+	}
+
+	strcpy(card->driver, f_midi_longname);
+	strcpy(card->longname, f_midi_longname);
+	strcpy(card->shortname, f_midi_shortname);
+
+	/* Set up rawmidi */
+	snd_component_add(card, "MIDI");
+	err = snd_rawmidi_new(card, card->longname, 0,
+			      midi->out_ports, midi->in_ports, &rmidi);
+	if (err < 0) {
+		ERROR(midi, "snd_rawmidi_new() failed: error %d\n", err);
+		goto fail;
+	}
+	midi->rmidi = rmidi;
+	midi->in_last_port = 0;
+	strcpy(rmidi->name, card->shortname);
+	rmidi->info_flags = SNDRV_RAWMIDI_INFO_OUTPUT |
+			    SNDRV_RAWMIDI_INFO_INPUT |
+			    SNDRV_RAWMIDI_INFO_DUPLEX;
+	rmidi->private_data = midi;
+	rmidi->private_free = f_midi_rmidi_free;
+	midi->free_ref++;
+
+	/*
+	 * Yes, rawmidi OUTPUT = USB IN, and rawmidi INPUT = USB OUT.
+	 * It's an upside-down world being a gadget.
+	 */
+	snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT, &gmidi_in_ops);
+	snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT, &gmidi_out_ops);
+
+	/* register it - we're ready to go */
+	err = snd_card_register(card);
+	if (err < 0) {
+		ERROR(midi, "snd_card_register() failed\n");
+		goto fail;
+	}
+
+	VDBG(midi, "%s() finished ok\n", __func__);
+	return 0;
+
+fail:
+	f_midi_unregister_card(midi);
+	return err;
+}
+
+/* MIDI function driver setup/binding */
+
+static int f_midi_bind(struct usb_configuration *c, struct usb_function *f)
+{
+	struct usb_descriptor_header **midi_function;
+	struct usb_midi_in_jack_descriptor jack_in_ext_desc[MAX_PORTS];
+	struct usb_midi_in_jack_descriptor jack_in_emb_desc[MAX_PORTS];
+	struct usb_midi_out_jack_descriptor_1 jack_out_ext_desc[MAX_PORTS];
+	struct usb_midi_out_jack_descriptor_1 jack_out_emb_desc[MAX_PORTS];
+	struct usb_composite_dev *cdev = c->cdev;
+	struct f_midi *midi = func_to_midi(f);
+	struct usb_string *us;
+	int status, n, jack = 1, i = 0, endpoint_descriptor_index = 0;
+
+	midi->gadget = cdev->gadget;
+	INIT_WORK(&midi->work, f_midi_in_work);
+	status = f_midi_register_card(midi);
+	if (status < 0)
+		goto fail_register;
+
+	/* maybe allocate device-global string ID */
+	us = usb_gstrings_attach(c->cdev, midi_strings,
+				 ARRAY_SIZE(midi_string_defs));
+	if (IS_ERR(us)) {
+		status = PTR_ERR(us);
+		goto fail;
+	}
+	ac_interface_desc.iInterface = us[STRING_FUNC_IDX].id;
+
+	/* We have two interfaces, AudioControl and MIDIStreaming */
+	status = usb_interface_id(c, f);
+	if (status < 0)
+		goto fail;
+	ac_interface_desc.bInterfaceNumber = status;
+
+	status = usb_interface_id(c, f);
+	if (status < 0)
+		goto fail;
+	ms_interface_desc.bInterfaceNumber = status;
+	ac_header_desc.baInterfaceNr[0] = status;
+	midi->ms_id = status;
+
+	status = -ENODEV;
+
+	/* allocate instance-specific endpoints */
+	midi->in_ep = usb_ep_autoconfig(cdev->gadget, &bulk_in_desc);
+	if (!midi->in_ep)
+		goto fail;
+
+	midi->out_ep = usb_ep_autoconfig(cdev->gadget, &bulk_out_desc);
+	if (!midi->out_ep)
+		goto fail;
+
+	/* allocate temporary function list */
+	midi_function = kcalloc((MAX_PORTS * 4) + 11, sizeof(*midi_function),
+				GFP_KERNEL);
+	if (!midi_function) {
+		status = -ENOMEM;
+		goto fail;
+	}
+
+	/*
+	 * construct the function's descriptor set. As the number of
+	 * input and output MIDI ports is configurable, we have to do
+	 * it that way.
+	 */
+
+	/* add the headers - these are always the same */
+	midi_function[i++] = (struct usb_descriptor_header *) &ac_interface_desc;
+	midi_function[i++] = (struct usb_descriptor_header *) &ac_header_desc;
+	midi_function[i++] = (struct usb_descriptor_header *) &ms_interface_desc;
+
+	/* calculate the header's wTotalLength */
+	n = USB_DT_MS_HEADER_SIZE
+		+ (midi->in_ports + midi->out_ports) *
+			(USB_DT_MIDI_IN_SIZE + USB_DT_MIDI_OUT_SIZE(1));
+	ms_header_desc.wTotalLength = cpu_to_le16(n);
+
+	midi_function[i++] = (struct usb_descriptor_header *) &ms_header_desc;
+
+	/* configure the external IN jacks, each linked to an embedded OUT jack */
+	for (n = 0; n < midi->in_ports; n++) {
+		struct usb_midi_in_jack_descriptor *in_ext = &jack_in_ext_desc[n];
+		struct usb_midi_out_jack_descriptor_1 *out_emb = &jack_out_emb_desc[n];
+
+		in_ext->bLength			= USB_DT_MIDI_IN_SIZE;
+		in_ext->bDescriptorType		= USB_DT_CS_INTERFACE;
+		in_ext->bDescriptorSubtype	= USB_MS_MIDI_IN_JACK;
+		in_ext->bJackType		= USB_MS_EXTERNAL;
+		in_ext->bJackID			= jack++;
+		in_ext->iJack			= 0;
+		midi_function[i++] = (struct usb_descriptor_header *) in_ext;
+
+		out_emb->bLength		= USB_DT_MIDI_OUT_SIZE(1);
+		out_emb->bDescriptorType	= USB_DT_CS_INTERFACE;
+		out_emb->bDescriptorSubtype	= USB_MS_MIDI_OUT_JACK;
+		out_emb->bJackType		= USB_MS_EMBEDDED;
+		out_emb->bJackID		= jack++;
+		out_emb->bNrInputPins		= 1;
+		out_emb->pins[0].baSourcePin	= 1;
+		out_emb->pins[0].baSourceID	= in_ext->bJackID;
+		out_emb->iJack			= 0;
+		midi_function[i++] = (struct usb_descriptor_header *) out_emb;
+
+		/* link it to the endpoint */
+		ms_in_desc.baAssocJackID[n] = out_emb->bJackID;
+	}
+
+	/* configure the external OUT jacks, each linked to an embedded IN jack */
+	for (n = 0; n < midi->out_ports; n++) {
+		struct usb_midi_in_jack_descriptor *in_emb = &jack_in_emb_desc[n];
+		struct usb_midi_out_jack_descriptor_1 *out_ext = &jack_out_ext_desc[n];
+
+		in_emb->bLength			= USB_DT_MIDI_IN_SIZE;
+		in_emb->bDescriptorType		= USB_DT_CS_INTERFACE;
+		in_emb->bDescriptorSubtype	= USB_MS_MIDI_IN_JACK;
+		in_emb->bJackType		= USB_MS_EMBEDDED;
+		in_emb->bJackID			= jack++;
+		in_emb->iJack			= 0;
+		midi_function[i++] = (struct usb_descriptor_header *) in_emb;
+
+		out_ext->bLength =		USB_DT_MIDI_OUT_SIZE(1);
+		out_ext->bDescriptorType =	USB_DT_CS_INTERFACE;
+		out_ext->bDescriptorSubtype =	USB_MS_MIDI_OUT_JACK;
+		out_ext->bJackType =		USB_MS_EXTERNAL;
+		out_ext->bJackID =		jack++;
+		out_ext->bNrInputPins =		1;
+		out_ext->iJack =		0;
+		out_ext->pins[0].baSourceID =	in_emb->bJackID;
+		out_ext->pins[0].baSourcePin =	1;
+		midi_function[i++] = (struct usb_descriptor_header *) out_ext;
+
+		/* link it to the endpoint */
+		ms_out_desc.baAssocJackID[n] = in_emb->bJackID;
+	}
+
+	/* configure the endpoint descriptors ... */
+	ms_out_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->in_ports);
+	ms_out_desc.bNumEmbMIDIJack = midi->in_ports;
+
+	ms_in_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->out_ports);
+	ms_in_desc.bNumEmbMIDIJack = midi->out_ports;
+
+	/* ... and add them to the list */
+	endpoint_descriptor_index = i;
+	midi_function[i++] = (struct usb_descriptor_header *) &bulk_out_desc;
+	midi_function[i++] = (struct usb_descriptor_header *) &ms_out_desc;
+	midi_function[i++] = (struct usb_descriptor_header *) &bulk_in_desc;
+	midi_function[i++] = (struct usb_descriptor_header *) &ms_in_desc;
+	midi_function[i++] = NULL;
+
+	/*
+	 * support all relevant hardware speeds... we expect that when
+	 * hardware is dual speed, all bulk-capable endpoints work at
+	 * both speeds
+	 */
+	/* copy descriptors, and track endpoint copies */
+	f->fs_descriptors = usb_copy_descriptors(midi_function);
+	if (!f->fs_descriptors)
+		goto fail_f_midi;
+
+	if (gadget_is_dualspeed(c->cdev->gadget)) {
+		bulk_in_desc.wMaxPacketSize = cpu_to_le16(512);
+		bulk_out_desc.wMaxPacketSize = cpu_to_le16(512);
+		f->hs_descriptors = usb_copy_descriptors(midi_function);
+		if (!f->hs_descriptors)
+			goto fail_f_midi;
+	}
+
+	if (gadget_is_superspeed(c->cdev->gadget)) {
+		bulk_in_desc.wMaxPacketSize = cpu_to_le16(1024);
+		bulk_out_desc.wMaxPacketSize = cpu_to_le16(1024);
+		i = endpoint_descriptor_index;
+		midi_function[i++] = (struct usb_descriptor_header *)
+				     &bulk_out_desc;
+		midi_function[i++] = (struct usb_descriptor_header *)
+				     &bulk_out_ss_comp_desc;
+		midi_function[i++] = (struct usb_descriptor_header *)
+				     &ms_out_desc;
+		midi_function[i++] = (struct usb_descriptor_header *)
+				     &bulk_in_desc;
+		midi_function[i++] = (struct usb_descriptor_header *)
+				     &bulk_in_ss_comp_desc;
+		midi_function[i++] = (struct usb_descriptor_header *)
+				     &ms_in_desc;
+		f->ss_descriptors = usb_copy_descriptors(midi_function);
+		if (!f->ss_descriptors)
+			goto fail_f_midi;
+
+		if (gadget_is_superspeed_plus(c->cdev->gadget)) {
+			f->ssp_descriptors = usb_copy_descriptors(midi_function);
+			if (!f->ssp_descriptors)
+				goto fail_f_midi;
+		}
+	}
+
+	kfree(midi_function);
+
+	return 0;
+
+fail_f_midi:
+	kfree(midi_function);
+	usb_free_all_descriptors(f);
+fail:
+	f_midi_unregister_card(midi);
+fail_register:
+	ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
+
+	return status;
+}
+
+static inline struct f_midi_opts *to_f_midi_opts(struct config_item *item)
+{
+	return container_of(to_config_group(item), struct f_midi_opts,
+			    func_inst.group);
+}
+
+static void midi_attr_release(struct config_item *item)
+{
+	struct f_midi_opts *opts = to_f_midi_opts(item);
+
+	usb_put_function_instance(&opts->func_inst);
+}
+
+static struct configfs_item_operations midi_item_ops = {
+	.release	= midi_attr_release,
+};
+
+#define F_MIDI_OPT(name, test_limit, limit)				\
+static ssize_t f_midi_opts_##name##_show(struct config_item *item, char *page) \
+{									\
+	struct f_midi_opts *opts = to_f_midi_opts(item);		\
+	int result;							\
+									\
+	mutex_lock(&opts->lock);					\
+	result = sprintf(page, "%u\n", opts->name);			\
+	mutex_unlock(&opts->lock);					\
+									\
+	return result;							\
+}									\
+									\
+static ssize_t f_midi_opts_##name##_store(struct config_item *item,	\
+					 const char *page, size_t len)	\
+{									\
+	struct f_midi_opts *opts = to_f_midi_opts(item);		\
+	int ret;							\
+	u32 num;							\
+									\
+	mutex_lock(&opts->lock);					\
+	if (opts->refcnt > 1) {						\
+		ret = -EBUSY;						\
+		goto end;						\
+	}								\
+									\
+	ret = kstrtou32(page, 0, &num);					\
+	if (ret)							\
+		goto end;						\
+									\
+	if (test_limit && num > limit) {				\
+		ret = -EINVAL;						\
+		goto end;						\
+	}								\
+	opts->name = num;						\
+	ret = len;							\
+									\
+end:									\
+	mutex_unlock(&opts->lock);					\
+	return ret;							\
+}									\
+									\
+CONFIGFS_ATTR(f_midi_opts_, name);
+
+#define F_MIDI_OPT_SIGNED(name, test_limit, limit)				\
+static ssize_t f_midi_opts_##name##_show(struct config_item *item, char *page) \
+{									\
+	struct f_midi_opts *opts = to_f_midi_opts(item);		\
+	int result;							\
+									\
+	mutex_lock(&opts->lock);					\
+	result = sprintf(page, "%d\n", opts->name);			\
+	mutex_unlock(&opts->lock);					\
+									\
+	return result;							\
+}									\
+									\
+static ssize_t f_midi_opts_##name##_store(struct config_item *item,	\
+					 const char *page, size_t len)	\
+{									\
+	struct f_midi_opts *opts = to_f_midi_opts(item);		\
+	int ret;							\
+	s32 num;							\
+									\
+	mutex_lock(&opts->lock);					\
+	if (opts->refcnt > 1) {						\
+		ret = -EBUSY;						\
+		goto end;						\
+	}								\
+									\
+	ret = kstrtos32(page, 0, &num);					\
+	if (ret)							\
+		goto end;						\
+									\
+	if (test_limit && num > limit) {				\
+		ret = -EINVAL;						\
+		goto end;						\
+	}								\
+	opts->name = num;						\
+	ret = len;							\
+									\
+end:									\
+	mutex_unlock(&opts->lock);					\
+	return ret;							\
+}									\
+									\
+CONFIGFS_ATTR(f_midi_opts_, name);
+
+F_MIDI_OPT_SIGNED(index, true, SNDRV_CARDS);
+F_MIDI_OPT(buflen, false, 0);
+F_MIDI_OPT(qlen, false, 0);
+F_MIDI_OPT(in_ports, true, MAX_PORTS);
+F_MIDI_OPT(out_ports, true, MAX_PORTS);
+
+static ssize_t f_midi_opts_id_show(struct config_item *item, char *page)
+{
+	struct f_midi_opts *opts = to_f_midi_opts(item);
+	int result;
+
+	mutex_lock(&opts->lock);
+	if (opts->id) {
+		result = strlcpy(page, opts->id, PAGE_SIZE);
+	} else {
+		page[0] = 0;
+		result = 0;
+	}
+
+	mutex_unlock(&opts->lock);
+
+	return result;
+}
+
+static ssize_t f_midi_opts_id_store(struct config_item *item,
+				    const char *page, size_t len)
+{
+	struct f_midi_opts *opts = to_f_midi_opts(item);
+	int ret;
+	char *c;
+
+	mutex_lock(&opts->lock);
+	if (opts->refcnt > 1) {
+		ret = -EBUSY;
+		goto end;
+	}
+
+	c = kstrndup(page, len, GFP_KERNEL);
+	if (!c) {
+		ret = -ENOMEM;
+		goto end;
+	}
+	if (opts->id_allocated)
+		kfree(opts->id);
+	opts->id = c;
+	opts->id_allocated = true;
+	ret = len;
+end:
+	mutex_unlock(&opts->lock);
+	return ret;
+}
+
+CONFIGFS_ATTR(f_midi_opts_, id);
+
+static struct configfs_attribute *midi_attrs[] = {
+	&f_midi_opts_attr_index,
+	&f_midi_opts_attr_buflen,
+	&f_midi_opts_attr_qlen,
+	&f_midi_opts_attr_in_ports,
+	&f_midi_opts_attr_out_ports,
+	&f_midi_opts_attr_id,
+	NULL,
+};
+
+static const struct config_item_type midi_func_type = {
+	.ct_item_ops	= &midi_item_ops,
+	.ct_attrs	= midi_attrs,
+	.ct_owner	= THIS_MODULE,
+};
+
+static void f_midi_free_inst(struct usb_function_instance *f)
+{
+	struct f_midi_opts *opts;
+	bool free = false;
+
+	opts = container_of(f, struct f_midi_opts, func_inst);
+
+	mutex_lock(&opts->lock);
+	if (!--opts->refcnt) {
+		free = true;
+	}
+	mutex_unlock(&opts->lock);
+
+	if (free) {
+		if (opts->id_allocated)
+			kfree(opts->id);
+		kfree(opts);
+	}
+}
+
+static struct usb_function_instance *f_midi_alloc_inst(void)
+{
+	struct f_midi_opts *opts;
+
+	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
+	if (!opts)
+		return ERR_PTR(-ENOMEM);
+
+	mutex_init(&opts->lock);
+	opts->func_inst.free_func_inst = f_midi_free_inst;
+	opts->index = SNDRV_DEFAULT_IDX1;
+	opts->id = SNDRV_DEFAULT_STR1;
+	opts->buflen = 512;
+	opts->qlen = 32;
+	opts->in_ports = 1;
+	opts->out_ports = 1;
+	opts->refcnt = 1;
+
+	config_group_init_type_name(&opts->func_inst.group, "",
+				    &midi_func_type);
+
+	return &opts->func_inst;
+}
+
+static void f_midi_free(struct usb_function *f)
+{
+	struct f_midi *midi;
+	struct f_midi_opts *opts;
+	bool free = false;
+
+	midi = func_to_midi(f);
+	opts = container_of(f->fi, struct f_midi_opts, func_inst);
+	mutex_lock(&opts->lock);
+	if (!--midi->free_ref) {
+		kfree(midi->id);
+		kfifo_free(&midi->in_req_fifo);
+		kfree(midi);
+		free = true;
+	}
+	mutex_unlock(&opts->lock);
+
+	if (free)
+		f_midi_free_inst(&opts->func_inst);
+}
+
+static void f_midi_rmidi_free(struct snd_rawmidi *rmidi)
+{
+	f_midi_free(rmidi->private_data);
+}
+
+static void f_midi_unbind(struct usb_configuration *c, struct usb_function *f)
+{
+	struct usb_composite_dev *cdev = f->config->cdev;
+	struct f_midi *midi = func_to_midi(f);
+	struct snd_card *card;
+
+	DBG(cdev, "unbind\n");
+
+	/* just to be sure */
+	f_midi_disable(f);
+
+	card = midi->card;
+	midi->card = NULL;
+	if (card)
+		snd_card_free_when_closed(card);
+
+	usb_free_all_descriptors(f);
+}
+
+static struct usb_function *f_midi_alloc(struct usb_function_instance *fi)
+{
+	struct f_midi *midi = NULL;
+	struct f_midi_opts *opts;
+	int status, i;
+
+	opts = container_of(fi, struct f_midi_opts, func_inst);
+
+	mutex_lock(&opts->lock);
+	/* sanity check */
+	if (opts->in_ports > MAX_PORTS || opts->out_ports > MAX_PORTS) {
+		status = -EINVAL;
+		goto setup_fail;
+	}
+
+	/* allocate and initialize one new instance */
+	midi = kzalloc(struct_size(midi, in_ports_array, opts->in_ports),
+		       GFP_KERNEL);
+	if (!midi) {
+		status = -ENOMEM;
+		goto setup_fail;
+	}
+
+	for (i = 0; i < opts->in_ports; i++)
+		midi->in_ports_array[i].cable = i;
+
+	/* set up ALSA midi devices */
+	midi->id = kstrdup(opts->id, GFP_KERNEL);
+	if (opts->id && !midi->id) {
+		status = -ENOMEM;
+		goto midi_free;
+	}
+	midi->in_ports = opts->in_ports;
+	midi->out_ports = opts->out_ports;
+	midi->index = opts->index;
+	midi->buflen = opts->buflen;
+	midi->qlen = opts->qlen;
+	midi->in_last_port = 0;
+	midi->free_ref = 1;
+
+	status = kfifo_alloc(&midi->in_req_fifo, midi->qlen, GFP_KERNEL);
+	if (status)
+		goto midi_free;
+
+	spin_lock_init(&midi->transmit_lock);
+
+	++opts->refcnt;
+	mutex_unlock(&opts->lock);
+
+	midi->func.name		= "gmidi function";
+	midi->func.bind		= f_midi_bind;
+	midi->func.unbind	= f_midi_unbind;
+	midi->func.set_alt	= f_midi_set_alt;
+	midi->func.disable	= f_midi_disable;
+	midi->func.free_func	= f_midi_free;
+
+	return &midi->func;
+
+midi_free:
+	if (midi)
+		kfree(midi->id);
+	kfree(midi);
+setup_fail:
+	mutex_unlock(&opts->lock);
+
+	return ERR_PTR(status);
+}
+
+DECLARE_USB_FUNCTION_INIT(midi, f_midi_alloc_inst, f_midi_alloc);