midi.c

  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(line6->line6midi->substream_receive,
 31				    data, 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, chunk, req);
 50
 51		if (done == 0)
 52			break;
 53
 54		line6_midibuf_write(mb, chunk, done);
 55		snd_rawmidi_transmit_ack(substream, done);
 56	}
 57
 58	for (;;) {
 59		done = line6_midibuf_read(mb, chunk,
 60					  LINE6_FALLBACK_MAXPACKETSIZE,
 61					  LINE6_MIDIBUF_READ_TX);
 62
 63		if (done == 0)
 64			break;
 65
 66		send_midi_async(line6, chunk, 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(urb->transfer_buffer);
 81	usb_free_urb(urb);
 82
 83	if (status == -ESHUTDOWN)
 84		return;
 85
 86	guard(spinlock_irqsave)(&line6->line6midi->lock);
 87	num = --line6->line6midi->num_active_send_urbs;
 88
 89	if (num == 0) {
 90		line6_midi_transmit(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(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, line6->usbdev,
123			 usb_sndintpipe(line6->usbdev,
124					 line6->properties->ep_ctrl_w),
125			 transfer_buffer, length, midi_sent, line6,
126			 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)(&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(line6->card, "Line 6 MIDI", 0, 1, 1, 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, SNDRV_RAWMIDI_STREAM_OUTPUT,
233			    &line6_midi_output_ops);
234	snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT,
235			    &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(&line6midi->midibuf_in);
245	line6_midibuf_destroy(&line6midi->midibuf_out);
246	kfree(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);
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(&line6midi->midibuf_in, MIDI_BUFFER_SIZE, 0);
279	if (err < 0)
280		return err;
281
282	err = line6_midibuf_init(&line6midi->midibuf_out, MIDI_BUFFER_SIZE, 1);
283	if (err < 0)
284		return err;
285
286	line6->line6midi = line6midi;
287	return 0;
288}
289EXPORT_SYMBOL_GPL(line6_init_midi);