1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Line 6 Linux USB driver
4 *
5 * Copyright (C) 2004-2010 Markus Grabner (line6@grabner-graz.at)
6 */
7
8#include <linux/slab.h>
9#include <linux/usb.h>
10#include <linux/export.h>
11#include <sound/core.h>
12#include <sound/rawmidi.h>
13
14#include "driver.h"
15#include "midi.h"
16
17#define line6_rawmidi_substream_midi(substream) \
18 ((struct snd_line6_midi *)((substream)->rmidi->private_data))
19
20static int send_midi_async(struct usb_line6 *line6, unsigned char *data,
21 int length);
22
23/*
24 Pass data received via USB to MIDI.
25*/
26void line6_midi_receive(struct usb_line6 *line6, unsigned char *data,
27 int length)
28{
29 if (line6->line6midi->substream_receive)
30 snd_rawmidi_receive(substream: line6->line6midi->substream_receive,
31 buffer: data, count: length);
32}
33
34/*
35 Read data from MIDI buffer and transmit them via USB.
36*/
37static void line6_midi_transmit(struct snd_rawmidi_substream *substream)
38{
39 struct usb_line6 *line6 =
40 line6_rawmidi_substream_midi(substream)->line6;
41 struct snd_line6_midi *line6midi = line6->line6midi;
42 struct midi_buffer *mb = &line6midi->midibuf_out;
43 unsigned char chunk[LINE6_FALLBACK_MAXPACKETSIZE];
44 int req, done;
45
46 for (;;) {
47 req = min3(line6_midibuf_bytes_free(mb), line6->max_packet_size,
48 LINE6_FALLBACK_MAXPACKETSIZE);
49 done = snd_rawmidi_transmit_peek(substream, buffer: chunk, count: req);
50
51 if (done == 0)
52 break;
53
54 line6_midibuf_write(mb, data: chunk, length: done);
55 snd_rawmidi_transmit_ack(substream, count: done);
56 }
57
58 for (;;) {
59 done = line6_midibuf_read(mb, data: chunk,
60 LINE6_FALLBACK_MAXPACKETSIZE,
61 LINE6_MIDIBUF_READ_TX);
62
63 if (done == 0)
64 break;
65
66 send_midi_async(line6, data: chunk, length: done);
67 }
68}
69
70/*
71 Notification of completion of MIDI transmission.
72*/
73static void midi_sent(struct urb *urb)
74{
75 int status;
76 int num;
77 struct usb_line6 *line6 = (struct usb_line6 *)urb->context;
78
79 status = urb->status;
80 kfree(objp: urb->transfer_buffer);
81 usb_free_urb(urb);
82
83 if (status == -ESHUTDOWN)
84 return;
85
86 guard(spinlock_irqsave)(l: &line6->line6midi->lock);
87 num = --line6->line6midi->num_active_send_urbs;
88
89 if (num == 0) {
90 line6_midi_transmit(substream: line6->line6midi->substream_transmit);
91 num = line6->line6midi->num_active_send_urbs;
92 }
93
94 if (num == 0)
95 wake_up(&line6->line6midi->send_wait);
96}
97
98/*
99 Send an asynchronous MIDI message.
100 Assumes that line6->line6midi->lock is held
101 (i.e., this function is serialized).
102*/
103static int send_midi_async(struct usb_line6 *line6, unsigned char *data,
104 int length)
105{
106 struct urb *urb;
107 int retval;
108 unsigned char *transfer_buffer;
109
110 urb = usb_alloc_urb(iso_packets: 0, GFP_ATOMIC);
111
112 if (urb == NULL)
113 return -ENOMEM;
114
115 transfer_buffer = kmemdup(data, length, GFP_ATOMIC);
116
117 if (transfer_buffer == NULL) {
118 usb_free_urb(urb);
119 return -ENOMEM;
120 }
121
122 usb_fill_int_urb(urb, dev: line6->usbdev,
123 usb_sndintpipe(line6->usbdev,
124 line6->properties->ep_ctrl_w),
125 transfer_buffer, buffer_length: length, complete_fn: midi_sent, context: line6,
126 interval: line6->interval);
127 urb->actual_length = 0;
128 retval = usb_urb_ep_type_check(urb);
129 if (retval < 0)
130 goto error;
131
132 retval = usb_submit_urb(urb, GFP_ATOMIC);
133 if (retval < 0)
134 goto error;
135
136 ++line6->line6midi->num_active_send_urbs;
137 return 0;
138
139 error:
140 dev_err(line6->ifcdev, "usb_submit_urb failed\n");
141 usb_free_urb(urb);
142 return retval;
143}
144
145static int line6_midi_output_open(struct snd_rawmidi_substream *substream)
146{
147 return 0;
148}
149
150static int line6_midi_output_close(struct snd_rawmidi_substream *substream)
151{
152 return 0;
153}
154
155static void line6_midi_output_trigger(struct snd_rawmidi_substream *substream,
156 int up)
157{
158 struct usb_line6 *line6 =
159 line6_rawmidi_substream_midi(substream)->line6;
160
161 line6->line6midi->substream_transmit = substream;
162 guard(spinlock_irqsave)(l: &line6->line6midi->lock);
163
164 if (line6->line6midi->num_active_send_urbs == 0)
165 line6_midi_transmit(substream);
166}
167
168static void line6_midi_output_drain(struct snd_rawmidi_substream *substream)
169{
170 struct usb_line6 *line6 =
171 line6_rawmidi_substream_midi(substream)->line6;
172 struct snd_line6_midi *midi = line6->line6midi;
173
174 wait_event_interruptible(midi->send_wait,
175 midi->num_active_send_urbs == 0);
176}
177
178static int line6_midi_input_open(struct snd_rawmidi_substream *substream)
179{
180 return 0;
181}
182
183static int line6_midi_input_close(struct snd_rawmidi_substream *substream)
184{
185 return 0;
186}
187
188static void line6_midi_input_trigger(struct snd_rawmidi_substream *substream,
189 int up)
190{
191 struct usb_line6 *line6 =
192 line6_rawmidi_substream_midi(substream)->line6;
193
194 if (up)
195 line6->line6midi->substream_receive = substream;
196 else
197 line6->line6midi->substream_receive = NULL;
198}
199
200static const struct snd_rawmidi_ops line6_midi_output_ops = {
201 .open = line6_midi_output_open,
202 .close = line6_midi_output_close,
203 .trigger = line6_midi_output_trigger,
204 .drain = line6_midi_output_drain,
205};
206
207static const struct snd_rawmidi_ops line6_midi_input_ops = {
208 .open = line6_midi_input_open,
209 .close = line6_midi_input_close,
210 .trigger = line6_midi_input_trigger,
211};
212
213/* Create a MIDI device */
214static int snd_line6_new_midi(struct usb_line6 *line6,
215 struct snd_rawmidi **rmidi_ret)
216{
217 struct snd_rawmidi *rmidi;
218 int err;
219
220 err = snd_rawmidi_new(card: line6->card, id: "Line 6 MIDI", device: 0, output_count: 1, input_count: 1, rmidi: rmidi_ret);
221 if (err < 0)
222 return err;
223
224 rmidi = *rmidi_ret;
225 strscpy(rmidi->id, line6->properties->id);
226 strscpy(rmidi->name, line6->properties->name);
227
228 rmidi->info_flags =
229 SNDRV_RAWMIDI_INFO_OUTPUT |
230 SNDRV_RAWMIDI_INFO_INPUT | SNDRV_RAWMIDI_INFO_DUPLEX;
231
232 snd_rawmidi_set_ops(rmidi, stream: SNDRV_RAWMIDI_STREAM_OUTPUT,
233 ops: &line6_midi_output_ops);
234 snd_rawmidi_set_ops(rmidi, stream: SNDRV_RAWMIDI_STREAM_INPUT,
235 ops: &line6_midi_input_ops);
236 return 0;
237}
238
239/* MIDI device destructor */
240static void snd_line6_midi_free(struct snd_rawmidi *rmidi)
241{
242 struct snd_line6_midi *line6midi = rmidi->private_data;
243
244 line6_midibuf_destroy(mb: &line6midi->midibuf_in);
245 line6_midibuf_destroy(mb: &line6midi->midibuf_out);
246 kfree(objp: line6midi);
247}
248
249/*
250 Initialize the Line 6 MIDI subsystem.
251*/
252int line6_init_midi(struct usb_line6 *line6)
253{
254 int err;
255 struct snd_rawmidi *rmidi;
256 struct snd_line6_midi *line6midi;
257
258 if (!(line6->properties->capabilities & LINE6_CAP_CONTROL_MIDI)) {
259 /* skip MIDI initialization and report success */
260 return 0;
261 }
262
263 err = snd_line6_new_midi(line6, rmidi_ret: &rmidi);
264 if (err < 0)
265 return err;
266
267 line6midi = kzalloc(sizeof(struct snd_line6_midi), GFP_KERNEL);
268 if (!line6midi)
269 return -ENOMEM;
270
271 rmidi->private_data = line6midi;
272 rmidi->private_free = snd_line6_midi_free;
273
274 init_waitqueue_head(&line6midi->send_wait);
275 spin_lock_init(&line6midi->lock);
276 line6midi->line6 = line6;
277
278 err = line6_midibuf_init(mb: &line6midi->midibuf_in, MIDI_BUFFER_SIZE, split: 0);
279 if (err < 0)
280 return err;
281
282 err = line6_midibuf_init(mb: &line6midi->midibuf_out, MIDI_BUFFER_SIZE, split: 1);
283 if (err < 0)
284 return err;
285
286 line6->line6midi = line6midi;
287 return 0;
288}
289EXPORT_SYMBOL_GPL(line6_init_midi);
290

source code of linux/sound/usb/line6/midi.c