path: root/drivers/usb/gadget/function/f_midi.c

/*
 * 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>
 *
 * Licensed under the GPL-2 or later.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/kfifo.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

/*
 * 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 f_midi *midi;
	int active;
	uint8_t cable;
	uint8_t state;
#define STATE_UNKNOWN	0
#define STATE_1PARAM	1
#define STATE_2PARAM_1	2
#define STATE_2PARAM_2	3
#define STATE_SYSEX_0	4
#define STATE_SYSEX_1	5
#define STATE_SYSEX_2	6
	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 *in_substream[MAX_PORTS];
	struct snd_rawmidi_substream *out_substream[MAX_PORTS];
	struct gmidi_in_port	*in_port[MAX_PORTS];

	unsigned long		out_triggered;
	struct tasklet_struct	tasklet;
	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 *);
	unsigned int in_last_port;
};

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);

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 = {