1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * gmidi.c -- USB MIDI Gadget Driver
4  *
5  * Copyright (C) 2006 Thumtronics Pty Ltd.
6  * Developed for Thumtronics by Grey Innovation
7  * Ben Williamson <ben.williamson@greyinnovation.com>
8  *
9  * This code is based in part on:
10  *
11  * Gadget Zero driver, Copyright (C) 2003-2004 David Brownell.
12  * USB Audio driver, Copyright (C) 2002 by Takashi Iwai.
13  * USB MIDI driver, Copyright (C) 2002-2005 Clemens Ladisch.
14  *
15  * Refer to the USB Device Class Definition for MIDI Devices:
16  * http://www.usb.org/developers/devclass_docs/midi10.pdf
17  */
18 
19 /* #define VERBOSE_DEBUG */
20 
21 #include <linux/kernel.h>
22 #include <linux/module.h>
23 
24 #include <sound/initval.h>
25 
26 #include <linux/usb/composite.h>
27 #include <linux/usb/gadget.h>
28 
29 #include "u_midi.h"
30 
31 /*-------------------------------------------------------------------------*/
32 
33 MODULE_AUTHOR("Ben Williamson");
34 MODULE_LICENSE("GPL v2");
35 
36 static const char longname[] = "MIDI Gadget";
37 
38 USB_GADGET_COMPOSITE_OPTIONS();
39 
40 static int index = SNDRV_DEFAULT_IDX1;
41 module_param(index, int, S_IRUGO);
42 MODULE_PARM_DESC(index, "Index value for the USB MIDI Gadget adapter.");
43 
44 static char *id = SNDRV_DEFAULT_STR1;
45 module_param(id, charp, S_IRUGO);
46 MODULE_PARM_DESC(id, "ID string for the USB MIDI Gadget adapter.");
47 
48 static unsigned int buflen = 512;
49 module_param(buflen, uint, S_IRUGO);
50 MODULE_PARM_DESC(buflen, "MIDI buffer length");
51 
52 static unsigned int qlen = 32;
53 module_param(qlen, uint, S_IRUGO);
54 MODULE_PARM_DESC(qlen, "USB read and write request queue length");
55 
56 static unsigned int in_ports = 1;
57 module_param(in_ports, uint, S_IRUGO);
58 MODULE_PARM_DESC(in_ports, "Number of MIDI input ports");
59 
60 static unsigned int out_ports = 1;
61 module_param(out_ports, uint, S_IRUGO);
62 MODULE_PARM_DESC(out_ports, "Number of MIDI output ports");
63 
64 /* Thanks to Grey Innovation for donating this product ID.
65  *
66  * DO NOT REUSE THESE IDs with a protocol-incompatible driver!!  Ever!!
67  * Instead:  allocate your own, using normal USB-IF procedures.
68  */
69 #define DRIVER_VENDOR_NUM	0x17b3		/* Grey Innovation */
70 #define DRIVER_PRODUCT_NUM	0x0004		/* Linux-USB "MIDI Gadget" */
71 
72 /* string IDs are assigned dynamically */
73 
74 #define STRING_DESCRIPTION_IDX		USB_GADGET_FIRST_AVAIL_IDX
75 
76 static struct usb_device_descriptor device_desc = {
77 	.bLength =		USB_DT_DEVICE_SIZE,
78 	.bDescriptorType =	USB_DT_DEVICE,
79 	/* .bcdUSB = DYNAMIC */
80 	.bDeviceClass =		USB_CLASS_PER_INTERFACE,
81 	.idVendor =		cpu_to_le16(DRIVER_VENDOR_NUM),
82 	.idProduct =		cpu_to_le16(DRIVER_PRODUCT_NUM),
83 	/* .iManufacturer =	DYNAMIC */
84 	/* .iProduct =		DYNAMIC */
85 	.bNumConfigurations =	1,
86 };
87 
88 static struct usb_string strings_dev[] = {
89 	[USB_GADGET_MANUFACTURER_IDX].s	= "Grey Innovation",
90 	[USB_GADGET_PRODUCT_IDX].s	= "MIDI Gadget",
91 	[USB_GADGET_SERIAL_IDX].s	= "",
92 	[STRING_DESCRIPTION_IDX].s	= "MIDI",
93 	{  } /* end of list */
94 };
95 
96 static struct usb_gadget_strings stringtab_dev = {
97 	.language	= 0x0409,	/* en-us */
98 	.strings	= strings_dev,
99 };
100 
101 static struct usb_gadget_strings *dev_strings[] = {
102 	&stringtab_dev,
103 	NULL,
104 };
105 
106 static struct usb_function_instance *fi_midi;
107 static struct usb_function *f_midi;
108 
midi_unbind(struct usb_composite_dev * dev)109 static int midi_unbind(struct usb_composite_dev *dev)
110 {
111 	usb_put_function(f_midi);
112 	usb_put_function_instance(fi_midi);
113 	return 0;
114 }
115 
116 static struct usb_configuration midi_config = {
117 	.label		= "MIDI Gadget",
118 	.bConfigurationValue = 1,
119 	/* .iConfiguration = DYNAMIC */
120 	.bmAttributes	= USB_CONFIG_ATT_ONE,
121 	.MaxPower	= CONFIG_USB_GADGET_VBUS_DRAW,
122 };
123 
midi_bind_config(struct usb_configuration * c)124 static int midi_bind_config(struct usb_configuration *c)
125 {
126 	int status;
127 
128 	f_midi = usb_get_function(fi_midi);
129 	if (IS_ERR(f_midi))
130 		return PTR_ERR(f_midi);
131 
132 	status = usb_add_function(c, f_midi);
133 	if (status < 0) {
134 		usb_put_function(f_midi);
135 		return status;
136 	}
137 
138 	return 0;
139 }
140 
midi_bind(struct usb_composite_dev * cdev)141 static int midi_bind(struct usb_composite_dev *cdev)
142 {
143 	struct f_midi_opts *midi_opts;
144 	int status;
145 
146 	fi_midi = usb_get_function_instance("midi");
147 	if (IS_ERR(fi_midi))
148 		return PTR_ERR(fi_midi);
149 
150 	midi_opts = container_of(fi_midi, struct f_midi_opts, func_inst);
151 	midi_opts->index = index;
152 	midi_opts->id = id;
153 	midi_opts->in_ports = in_ports;
154 	midi_opts->out_ports = out_ports;
155 	midi_opts->buflen = buflen;
156 	midi_opts->qlen = qlen;
157 
158 	status = usb_string_ids_tab(cdev, strings_dev);
159 	if (status < 0)
160 		goto put;
161 	device_desc.iManufacturer = strings_dev[USB_GADGET_MANUFACTURER_IDX].id;
162 	device_desc.iProduct = strings_dev[USB_GADGET_PRODUCT_IDX].id;
163 	midi_config.iConfiguration = strings_dev[STRING_DESCRIPTION_IDX].id;
164 
165 	status = usb_add_config(cdev, &midi_config, midi_bind_config);
166 	if (status < 0)
167 		goto put;
168 	usb_composite_overwrite_options(cdev, &coverwrite);
169 	pr_info("%s\n", longname);
170 	return 0;
171 put:
172 	usb_put_function_instance(fi_midi);
173 	return status;
174 }
175 
176 static struct usb_composite_driver midi_driver = {
177 	.name		= longname,
178 	.dev		= &device_desc,
179 	.strings	= dev_strings,
180 	.max_speed	= USB_SPEED_HIGH,
181 	.bind		= midi_bind,
182 	.unbind		= midi_unbind,
183 };
184 
185 module_usb_composite_driver(midi_driver);
186