xref: /linux/sound/usb/line6/midi.c (revision 05a54fa773284d1a7923cdfdd8f0c8dabb98bd26)
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 
20 static 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 */
26 void 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 */
37 static 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 */
73 static 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 */
103 static 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 
145 static int line6_midi_output_open(struct snd_rawmidi_substream *substream)
146 {
147 	return 0;
148 }
149 
150 static int line6_midi_output_close(struct snd_rawmidi_substream *substream)
151 {
152 	return 0;
153 }
154 
155 static 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 
168 static 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 
178 static int line6_midi_input_open(struct snd_rawmidi_substream *substream)
179 {
180 	return 0;
181 }
182 
183 static int line6_midi_input_close(struct snd_rawmidi_substream *substream)
184 {
185 	return 0;
186 }
187 
188 static 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 
200 static 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 
207 static 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 */
214 static 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 */
240 static 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 */
252 int 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 }
289 EXPORT_SYMBOL_GPL(line6_init_midi);
290