xref: /openbmc/linux/sound/usb/line6/midi.c (revision b8800d32)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Line 6 Linux USB driver
4  *
5  * Copyright (C) 2004-2010 Markus Grabner (grabner@icg.tugraz.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 */
line6_midi_receive(struct usb_line6 * line6,unsigned char * data,int length)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 */
line6_midi_transmit(struct snd_rawmidi_substream * substream)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 */
midi_sent(struct urb * urb)73 static void midi_sent(struct urb *urb)
74 {
75 	unsigned long flags;
76 	int status;
77 	int num;
78 	struct usb_line6 *line6 = (struct usb_line6 *)urb->context;
79 
80 	status = urb->status;
81 	kfree(urb->transfer_buffer);
82 	usb_free_urb(urb);
83 
84 	if (status == -ESHUTDOWN)
85 		return;
86 
87 	spin_lock_irqsave(&line6->line6midi->lock, flags);
88 	num = --line6->line6midi->num_active_send_urbs;
89 
90 	if (num == 0) {
91 		line6_midi_transmit(line6->line6midi->substream_transmit);
92 		num = line6->line6midi->num_active_send_urbs;
93 	}
94 
95 	if (num == 0)
96 		wake_up(&line6->line6midi->send_wait);
97 
98 	spin_unlock_irqrestore(&line6->line6midi->lock, flags);
99 }
100 
101 /*
102 	Send an asynchronous MIDI message.
103 	Assumes that line6->line6midi->lock is held
104 	(i.e., this function is serialized).
105 */
send_midi_async(struct usb_line6 * line6,unsigned char * data,int length)106 static int send_midi_async(struct usb_line6 *line6, unsigned char *data,
107 			   int length)
108 {
109 	struct urb *urb;
110 	int retval;
111 	unsigned char *transfer_buffer;
112 
113 	urb = usb_alloc_urb(0, GFP_ATOMIC);
114 
115 	if (urb == NULL)
116 		return -ENOMEM;
117 
118 	transfer_buffer = kmemdup(data, length, GFP_ATOMIC);
119 
120 	if (transfer_buffer == NULL) {
121 		usb_free_urb(urb);
122 		return -ENOMEM;
123 	}
124 
125 	usb_fill_int_urb(urb, line6->usbdev,
126 			 usb_sndintpipe(line6->usbdev,
127 					 line6->properties->ep_ctrl_w),
128 			 transfer_buffer, length, midi_sent, line6,
129 			 line6->interval);
130 	urb->actual_length = 0;
131 	retval = usb_urb_ep_type_check(urb);
132 	if (retval < 0)
133 		goto error;
134 
135 	retval = usb_submit_urb(urb, GFP_ATOMIC);
136 	if (retval < 0)
137 		goto error;
138 
139 	++line6->line6midi->num_active_send_urbs;
140 	return 0;
141 
142  error:
143 	dev_err(line6->ifcdev, "usb_submit_urb failed\n");
144 	usb_free_urb(urb);
145 	return retval;
146 }
147 
line6_midi_output_open(struct snd_rawmidi_substream * substream)148 static int line6_midi_output_open(struct snd_rawmidi_substream *substream)
149 {
150 	return 0;
151 }
152 
line6_midi_output_close(struct snd_rawmidi_substream * substream)153 static int line6_midi_output_close(struct snd_rawmidi_substream *substream)
154 {
155 	return 0;
156 }
157 
line6_midi_output_trigger(struct snd_rawmidi_substream * substream,int up)158 static void line6_midi_output_trigger(struct snd_rawmidi_substream *substream,
159 				      int up)
160 {
161 	unsigned long flags;
162 	struct usb_line6 *line6 =
163 	    line6_rawmidi_substream_midi(substream)->line6;
164 
165 	line6->line6midi->substream_transmit = substream;
166 	spin_lock_irqsave(&line6->line6midi->lock, flags);
167 
168 	if (line6->line6midi->num_active_send_urbs == 0)
169 		line6_midi_transmit(substream);
170 
171 	spin_unlock_irqrestore(&line6->line6midi->lock, flags);
172 }
173 
line6_midi_output_drain(struct snd_rawmidi_substream * substream)174 static void line6_midi_output_drain(struct snd_rawmidi_substream *substream)
175 {
176 	struct usb_line6 *line6 =
177 	    line6_rawmidi_substream_midi(substream)->line6;
178 	struct snd_line6_midi *midi = line6->line6midi;
179 
180 	wait_event_interruptible(midi->send_wait,
181 				 midi->num_active_send_urbs == 0);
182 }
183 
line6_midi_input_open(struct snd_rawmidi_substream * substream)184 static int line6_midi_input_open(struct snd_rawmidi_substream *substream)
185 {
186 	return 0;
187 }
188 
line6_midi_input_close(struct snd_rawmidi_substream * substream)189 static int line6_midi_input_close(struct snd_rawmidi_substream *substream)
190 {
191 	return 0;
192 }
193 
line6_midi_input_trigger(struct snd_rawmidi_substream * substream,int up)194 static void line6_midi_input_trigger(struct snd_rawmidi_substream *substream,
195 				     int up)
196 {
197 	struct usb_line6 *line6 =
198 	    line6_rawmidi_substream_midi(substream)->line6;
199 
200 	if (up)
201 		line6->line6midi->substream_receive = substream;
202 	else
203 		line6->line6midi->substream_receive = NULL;
204 }
205 
206 static const struct snd_rawmidi_ops line6_midi_output_ops = {
207 	.open = line6_midi_output_open,
208 	.close = line6_midi_output_close,
209 	.trigger = line6_midi_output_trigger,
210 	.drain = line6_midi_output_drain,
211 };
212 
213 static const struct snd_rawmidi_ops line6_midi_input_ops = {
214 	.open = line6_midi_input_open,
215 	.close = line6_midi_input_close,
216 	.trigger = line6_midi_input_trigger,
217 };
218 
219 /* Create a MIDI device */
snd_line6_new_midi(struct usb_line6 * line6,struct snd_rawmidi ** rmidi_ret)220 static int snd_line6_new_midi(struct usb_line6 *line6,
221 			      struct snd_rawmidi **rmidi_ret)
222 {
223 	struct snd_rawmidi *rmidi;
224 	int err;
225 
226 	err = snd_rawmidi_new(line6->card, "Line 6 MIDI", 0, 1, 1, rmidi_ret);
227 	if (err < 0)
228 		return err;
229 
230 	rmidi = *rmidi_ret;
231 	strcpy(rmidi->id, line6->properties->id);
232 	strcpy(rmidi->name, line6->properties->name);
233 
234 	rmidi->info_flags =
235 	    SNDRV_RAWMIDI_INFO_OUTPUT |
236 	    SNDRV_RAWMIDI_INFO_INPUT | SNDRV_RAWMIDI_INFO_DUPLEX;
237 
238 	snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT,
239 			    &line6_midi_output_ops);
240 	snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT,
241 			    &line6_midi_input_ops);
242 	return 0;
243 }
244 
245 /* MIDI device destructor */
snd_line6_midi_free(struct snd_rawmidi * rmidi)246 static void snd_line6_midi_free(struct snd_rawmidi *rmidi)
247 {
248 	struct snd_line6_midi *line6midi = rmidi->private_data;
249 
250 	line6_midibuf_destroy(&line6midi->midibuf_in);
251 	line6_midibuf_destroy(&line6midi->midibuf_out);
252 	kfree(line6midi);
253 }
254 
255 /*
256 	Initialize the Line 6 MIDI subsystem.
257 */
line6_init_midi(struct usb_line6 * line6)258 int line6_init_midi(struct usb_line6 *line6)
259 {
260 	int err;
261 	struct snd_rawmidi *rmidi;
262 	struct snd_line6_midi *line6midi;
263 
264 	if (!(line6->properties->capabilities & LINE6_CAP_CONTROL_MIDI)) {
265 		/* skip MIDI initialization and report success */
266 		return 0;
267 	}
268 
269 	err = snd_line6_new_midi(line6, &rmidi);
270 	if (err < 0)
271 		return err;
272 
273 	line6midi = kzalloc(sizeof(struct snd_line6_midi), GFP_KERNEL);
274 	if (!line6midi)
275 		return -ENOMEM;
276 
277 	rmidi->private_data = line6midi;
278 	rmidi->private_free = snd_line6_midi_free;
279 
280 	init_waitqueue_head(&line6midi->send_wait);
281 	spin_lock_init(&line6midi->lock);
282 	line6midi->line6 = line6;
283 
284 	err = line6_midibuf_init(&line6midi->midibuf_in, MIDI_BUFFER_SIZE, 0);
285 	if (err < 0)
286 		return err;
287 
288 	err = line6_midibuf_init(&line6midi->midibuf_out, MIDI_BUFFER_SIZE, 1);
289 	if (err < 0)
290 		return err;
291 
292 	line6->line6midi = line6midi;
293 	return 0;
294 }
295 EXPORT_SYMBOL_GPL(line6_init_midi);
296