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 = min(line6_midibuf_bytes_free(mb), line6->max_packet_size);
48 		done = snd_rawmidi_transmit_peek(substream, chunk, req);
49 
50 		if (done == 0)
51 			break;
52 
53 		line6_midibuf_write(mb, chunk, done);
54 		snd_rawmidi_transmit_ack(substream, done);
55 	}
56 
57 	for (;;) {
58 		done = line6_midibuf_read(mb, chunk,
59 					  LINE6_FALLBACK_MAXPACKETSIZE);
60 
61 		if (done == 0)
62 			break;
63 
64 		send_midi_async(line6, chunk, done);
65 	}
66 }
67 
68 /*
69 	Notification of completion of MIDI transmission.
70 */
midi_sent(struct urb * urb)71 static void midi_sent(struct urb *urb)
72 {
73 	unsigned long flags;
74 	int status;
75 	int num;
76 	struct usb_line6 *line6 = (struct usb_line6 *)urb->context;
77 
78 	status = urb->status;
79 	kfree(urb->transfer_buffer);
80 	usb_free_urb(urb);
81 
82 	if (status == -ESHUTDOWN)
83 		return;
84 
85 	spin_lock_irqsave(&line6->line6midi->lock, flags);
86 	num = --line6->line6midi->num_active_send_urbs;
87 
88 	if (num == 0) {
89 		line6_midi_transmit(line6->line6midi->substream_transmit);
90 		num = line6->line6midi->num_active_send_urbs;
91 	}
92 
93 	if (num == 0)
94 		wake_up(&line6->line6midi->send_wait);
95 
96 	spin_unlock_irqrestore(&line6->line6midi->lock, flags);
97 }
98 
99 /*
100 	Send an asynchronous MIDI message.
101 	Assumes that line6->line6midi->lock is held
102 	(i.e., this function is serialized).
103 */
send_midi_async(struct usb_line6 * line6,unsigned char * data,int length)104 static int send_midi_async(struct usb_line6 *line6, unsigned char *data,
105 			   int length)
106 {
107 	struct urb *urb;
108 	int retval;
109 	unsigned char *transfer_buffer;
110 
111 	urb = usb_alloc_urb(0, GFP_ATOMIC);
112 
113 	if (urb == NULL)
114 		return -ENOMEM;
115 
116 	transfer_buffer = kmemdup(data, length, GFP_ATOMIC);
117 
118 	if (transfer_buffer == NULL) {
119 		usb_free_urb(urb);
120 		return -ENOMEM;
121 	}
122 
123 	usb_fill_int_urb(urb, line6->usbdev,
124 			 usb_sndintpipe(line6->usbdev,
125 					 line6->properties->ep_ctrl_w),
126 			 transfer_buffer, length, midi_sent, line6,
127 			 line6->interval);
128 	urb->actual_length = 0;
129 	retval = usb_urb_ep_type_check(urb);
130 	if (retval < 0)
131 		goto error;
132 
133 	retval = usb_submit_urb(urb, GFP_ATOMIC);
134 	if (retval < 0)
135 		goto error;
136 
137 	++line6->line6midi->num_active_send_urbs;
138 	return 0;
139 
140  error:
141 	dev_err(line6->ifcdev, "usb_submit_urb failed\n");
142 	usb_free_urb(urb);
143 	return retval;
144 }
145 
line6_midi_output_open(struct snd_rawmidi_substream * substream)146 static int line6_midi_output_open(struct snd_rawmidi_substream *substream)
147 {
148 	return 0;
149 }
150 
line6_midi_output_close(struct snd_rawmidi_substream * substream)151 static int line6_midi_output_close(struct snd_rawmidi_substream *substream)
152 {
153 	return 0;
154 }
155 
line6_midi_output_trigger(struct snd_rawmidi_substream * substream,int up)156 static void line6_midi_output_trigger(struct snd_rawmidi_substream *substream,
157 				      int up)
158 {
159 	unsigned long flags;
160 	struct usb_line6 *line6 =
161 	    line6_rawmidi_substream_midi(substream)->line6;
162 
163 	line6->line6midi->substream_transmit = substream;
164 	spin_lock_irqsave(&line6->line6midi->lock, flags);
165 
166 	if (line6->line6midi->num_active_send_urbs == 0)
167 		line6_midi_transmit(substream);
168 
169 	spin_unlock_irqrestore(&line6->line6midi->lock, flags);
170 }
171 
line6_midi_output_drain(struct snd_rawmidi_substream * substream)172 static void line6_midi_output_drain(struct snd_rawmidi_substream *substream)
173 {
174 	struct usb_line6 *line6 =
175 	    line6_rawmidi_substream_midi(substream)->line6;
176 	struct snd_line6_midi *midi = line6->line6midi;
177 
178 	wait_event_interruptible(midi->send_wait,
179 				 midi->num_active_send_urbs == 0);
180 }
181 
line6_midi_input_open(struct snd_rawmidi_substream * substream)182 static int line6_midi_input_open(struct snd_rawmidi_substream *substream)
183 {
184 	return 0;
185 }
186 
line6_midi_input_close(struct snd_rawmidi_substream * substream)187 static int line6_midi_input_close(struct snd_rawmidi_substream *substream)
188 {
189 	return 0;
190 }
191 
line6_midi_input_trigger(struct snd_rawmidi_substream * substream,int up)192 static void line6_midi_input_trigger(struct snd_rawmidi_substream *substream,
193 				     int up)
194 {
195 	struct usb_line6 *line6 =
196 	    line6_rawmidi_substream_midi(substream)->line6;
197 
198 	if (up)
199 		line6->line6midi->substream_receive = substream;
200 	else
201 		line6->line6midi->substream_receive = NULL;
202 }
203 
204 static const struct snd_rawmidi_ops line6_midi_output_ops = {
205 	.open = line6_midi_output_open,
206 	.close = line6_midi_output_close,
207 	.trigger = line6_midi_output_trigger,
208 	.drain = line6_midi_output_drain,
209 };
210 
211 static const struct snd_rawmidi_ops line6_midi_input_ops = {
212 	.open = line6_midi_input_open,
213 	.close = line6_midi_input_close,
214 	.trigger = line6_midi_input_trigger,
215 };
216 
217 /* Create a MIDI device */
snd_line6_new_midi(struct usb_line6 * line6,struct snd_rawmidi ** rmidi_ret)218 static int snd_line6_new_midi(struct usb_line6 *line6,
219 			      struct snd_rawmidi **rmidi_ret)
220 {
221 	struct snd_rawmidi *rmidi;
222 	int err;
223 
224 	err = snd_rawmidi_new(line6->card, "Line 6 MIDI", 0, 1, 1, rmidi_ret);
225 	if (err < 0)
226 		return err;
227 
228 	rmidi = *rmidi_ret;
229 	strcpy(rmidi->id, line6->properties->id);
230 	strcpy(rmidi->name, line6->properties->name);
231 
232 	rmidi->info_flags =
233 	    SNDRV_RAWMIDI_INFO_OUTPUT |
234 	    SNDRV_RAWMIDI_INFO_INPUT | SNDRV_RAWMIDI_INFO_DUPLEX;
235 
236 	snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT,
237 			    &line6_midi_output_ops);
238 	snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT,
239 			    &line6_midi_input_ops);
240 	return 0;
241 }
242 
243 /* MIDI device destructor */
snd_line6_midi_free(struct snd_rawmidi * rmidi)244 static void snd_line6_midi_free(struct snd_rawmidi *rmidi)
245 {
246 	struct snd_line6_midi *line6midi = rmidi->private_data;
247 
248 	line6_midibuf_destroy(&line6midi->midibuf_in);
249 	line6_midibuf_destroy(&line6midi->midibuf_out);
250 	kfree(line6midi);
251 }
252 
253 /*
254 	Initialize the Line 6 MIDI subsystem.
255 */
line6_init_midi(struct usb_line6 * line6)256 int line6_init_midi(struct usb_line6 *line6)
257 {
258 	int err;
259 	struct snd_rawmidi *rmidi;
260 	struct snd_line6_midi *line6midi;
261 
262 	if (!(line6->properties->capabilities & LINE6_CAP_CONTROL_MIDI)) {
263 		/* skip MIDI initialization and report success */
264 		return 0;
265 	}
266 
267 	err = snd_line6_new_midi(line6, &rmidi);
268 	if (err < 0)
269 		return err;
270 
271 	line6midi = kzalloc(sizeof(struct snd_line6_midi), GFP_KERNEL);
272 	if (!line6midi)
273 		return -ENOMEM;
274 
275 	rmidi->private_data = line6midi;
276 	rmidi->private_free = snd_line6_midi_free;
277 
278 	init_waitqueue_head(&line6midi->send_wait);
279 	spin_lock_init(&line6midi->lock);
280 	line6midi->line6 = line6;
281 
282 	err = line6_midibuf_init(&line6midi->midibuf_in, MIDI_BUFFER_SIZE, 0);
283 	if (err < 0)
284 		return err;
285 
286 	err = line6_midibuf_init(&line6midi->midibuf_out, MIDI_BUFFER_SIZE, 1);
287 	if (err < 0)
288 		return err;
289 
290 	line6->line6midi = line6midi;
291 	return 0;
292 }
293 EXPORT_SYMBOL_GPL(line6_init_midi);
294