1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
|
/*
* Line 6 Linux USB driver
*
* Copyright (C) 2004-2010 Markus Grabner (grabner@icg.tugraz.at)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation, version 2.
*
*/
/*
PCM interface to POD series devices.
*/
#ifndef PCM_H
#define PCM_H
#include <sound/pcm.h>
#include "driver.h"
#include "usbdefs.h"
/* number of URBs */
#define LINE6_ISO_BUFFERS 2
/*
number of USB frames per URB
The Line 6 Windows driver always transmits two frames per packet, but
the Linux driver performs significantly better (i.e., lower latency)
with only one frame per packet.
*/
#define LINE6_ISO_PACKETS 1
/* in a "full speed" device (such as the PODxt Pro) this means 1ms */
#define LINE6_ISO_INTERVAL 1
#define LINE6_IMPULSE_DEFAULT_PERIOD 100
/*
Get substream from Line 6 PCM data structure
*/
#define get_substream(line6pcm, stream) \
(line6pcm->pcm->streams[stream].substream)
/*
PCM mode bits.
There are several features of the Line 6 USB driver which require PCM
data to be exchanged with the device:
*) PCM playback and capture via ALSA
*) software monitoring (for devices without hardware monitoring)
*) optional impulse response measurement
However, from the device's point of view, there is just a single
capture and playback stream, which must be shared between these
subsystems. It is therefore necessary to maintain the state of the
subsystems with respect to PCM usage. We define several constants of
the form LINE6_BIT_PCM_<subsystem>_<direction>_<resource> with the
following meanings:
*) <subsystem> is one of
-) ALSA: PCM playback and capture via ALSA
-) MONITOR: software monitoring
-) IMPULSE: optional impulse response measurement
*) <direction> is one of
-) PLAYBACK: audio output (from host to device)
-) CAPTURE: audio input (from device to host)
*) <resource> is one of
-) BUFFER: buffer required by PCM data stream
-) STREAM: actual PCM data stream
The subsystems call line6_pcm_acquire() to acquire the (shared)
resources needed for a particular operation (e.g., allocate the buffer
for ALSA playback or start the capture stream for software monitoring).
When a resource is no longer needed, it is released by calling
line6_pcm_release(). Buffer allocation and stream startup are handled
separately to allow the ALSA kernel driver to perform them at
appropriate places (since the callback which starts a PCM stream is not
allowed to sleep).
*/
enum {
/* individual bit indices: */
LINE6_INDEX_PCM_ALSA_PLAYBACK_BUFFER,
LINE6_INDEX_PCM_ALSA_PLAYBACK_STREAM,
LINE6_INDEX_PCM_ALSA_CAPTURE_BUFFER,
LINE6_INDEX_PCM_ALSA_CAPTURE_STREAM,
LINE6_INDEX_PCM_MONITOR_PLAYBACK_BUFFER,
LINE6_INDEX_PCM_MONITOR_PLAYBACK_STREAM,
LINE6_INDEX_PCM_MONITOR_CAPTURE_BUFFER,
LINE6_INDEX_PCM_MONITOR_CAPTURE_STREAM,
LINE6_INDEX_PCM_IMPULSE_PLAYBACK_BUFFER,
LINE6_INDEX_PCM_IMPULSE_PLAYBACK_STREAM,
LINE6_INDEX_PCM_IMPULSE_CAPTURE_BUFFER,
LINE6_INDEX_PCM_IMPULSE_CAPTURE_STREAM,
LINE6_INDEX_PAUSE_PLAYBACK,
LINE6_INDEX_PREPARED,
#define LINE6_BIT(x) LINE6_BIT_ ## x = 1 << LINE6_INDEX_ ## x
/* individual bit masks: */
LINE6_BIT(PCM_ALSA_PLAYBACK_BUFFER),
LINE6_BIT(PCM_ALSA_PLAYBACK_STREAM),
LINE6_BIT(PCM_ALSA_CAPTURE_BUFFER),
LINE6_BIT(PCM_ALSA_CAPTURE_STREAM),
LINE6_BIT(PCM_MONITOR_PLAYBACK_BUFFER),
LINE6_BIT(PCM_MONITOR_PLAYBACK_STREAM),
LINE6_BIT(PCM_MONITOR_CAPTURE_BUFFER),
LINE6_BIT(PCM_MONITOR_CAPTURE_STREAM),
LINE6_BIT(PCM_IMPULSE_PLAYBACK_BUFFER),
LINE6_BIT(PCM_IMPULSE_PLAYBACK_STREAM),
LINE6_BIT(PCM_IMPULSE_CAPTURE_BUFFER),
LINE6_BIT(PCM_IMPULSE_CAPTURE_STREAM),
LINE6_BIT(PAUSE_PLAYBACK),
LINE6_BIT(PREPARED),
/* combined bit masks (by operation): */
LINE6_BITS_PCM_ALSA_BUFFER =
LINE6_BIT_PCM_ALSA_PLAYBACK_BUFFER |
LINE6_BIT_PCM_ALSA_CAPTURE_BUFFER,
LINE6_BITS_PCM_ALSA_STREAM =
LINE6_BIT_PCM_ALSA_PLAYBACK_STREAM |
LINE6_BIT_PCM_ALSA_CAPTURE_STREAM,
LINE6_BITS_PCM_MONITOR =
LINE6_BIT_PCM_MONITOR_PLAYBACK_BUFFER |
LINE6_BIT_PCM_MONITOR_PLAYBACK_STREAM |
LINE6_BIT_PCM_MONITOR_CAPTURE_BUFFER |
LINE6_BIT_PCM_MONITOR_CAPTURE_STREAM,
LINE6_BITS_PCM_IMPULSE =
LINE6_BIT_PCM_IMPULSE_PLAYBACK_BUFFER |
LINE6_BIT_PCM_IMPULSE_PLAYBACK_STREAM |
LINE6_BIT_PCM_IMPULSE_CAPTURE_BUFFER |
LINE6_BIT_PCM_IMPULSE_CAPTURE_STREAM,
/* combined bit masks (by direction): */
LINE6_BITS_PLAYBACK_BUFFER =
LINE6_BIT_PCM_IMPULSE_PLAYBACK_BUFFER |
LINE6_BIT_PCM_ALSA_PLAYBACK_BUFFER |
LINE6_BIT_PCM_MONITOR_PLAYBACK_BUFFER,
LINE6_BITS_PLAYBACK_STREAM =
LINE6_BIT_PCM_IMPULSE_PLAYBACK_STREAM |
LINE6_BIT_PCM_ALSA_PLAYBACK_STREAM |
LINE6_BIT_PCM_MONITOR_PLAYBACK_STREAM,
LINE6_BITS_CAPTURE_BUFFER =
LINE6_BIT_PCM_IMPULSE_CAPTURE_BUFFER |
LINE6_BIT_PCM_ALSA_CAPTURE_BUFFER |
LINE6_BIT_PCM_MONITOR_CAPTURE_BUFFER,
LINE6_BITS_CAPTURE_STREAM =
LINE6_BIT_PCM_IMPULSE_CAPTURE_STREAM |
LINE6_BIT_PCM_ALSA_CAPTURE_STREAM |
LINE6_BIT_PCM_MONITOR_CAPTURE_STREAM,
LINE6_BITS_STREAM =
LINE6_BITS_PLAYBACK_STREAM |
LINE6_BITS_CAPTURE_STREAM
};
struct line6_pcm_properties {
struct snd_pcm_hardware snd_line6_playback_hw, snd_line6_capture_hw;
struct snd_pcm_hw_constraint_ratdens snd_line6_rates;
int bytes_per_frame;
};
struct line6_pcm_stream {
/* allocated URBs */
struct urb *urbs[LINE6_ISO_BUFFERS];
/* Temporary buffer;
* Since the packet size is not known in advance, this buffer is
* large enough to store maximum size packets.
*/
unsigned char *buffer;
/* Free frame position in the buffer. */
snd_pcm_uframes_t pos;
/* Count processed bytes;
* This is modulo period size (to determine when a period is finished).
*/
unsigned bytes;
/* Counter to create desired sample rate */
unsigned count;
/* period size in bytes */
unsigned period;
/* Processed frame position in the buffer;
* The contents of the ring buffer have been consumed by the USB
* subsystem (i.e., sent to the USB device) up to this position.
*/
snd_pcm_uframes_t pos_done;
/* Bit mask of active URBs */
unsigned long active_urbs;
/* Bit mask of URBs currently being unlinked */
unsigned long unlink_urbs;
/* Spin lock to protect updates of the buffer positions (not contents)
*/
spinlock_t lock;
int last_frame;
};
struct snd_line6_pcm {
/**
Pointer back to the Line 6 driver data structure.
*/
struct usb_line6 *line6;
/**
Properties.
*/
struct line6_pcm_properties *properties;
/**
ALSA pcm stream
*/
struct snd_pcm *pcm;
/* Capture and playback streams */
struct line6_pcm_stream in;
struct line6_pcm_stream out;
/**
Previously captured frame (for software monitoring).
*/
unsigned char *prev_fbuf;
/**
Size of previously captured frame (for software monitoring).
*/
int prev_fsize;
/**
Maximum size of USB packet.
*/
int max_packet_size;
/**
PCM playback volume (left and right).
*/
int volume_playback[2];
/**
PCM monitor volume.
*/
int volume_monitor;
/**
Volume of impulse response test signal (if zero, test is disabled).
*/
int impulse_volume;
/**
Period of impulse response test signal.
*/
int impulse_period;
/**
Counter for impulse response test signal.
*/
int impulse_count;
/**
Several status bits (see LINE6_BIT_*).
*/
unsigned long flags;
};
extern int line6_init_pcm(struct usb_line6 *line6,
struct line6_pcm_properties *properties);
extern int snd_line6_trigger(struct snd_pcm_substream *substream, int cmd);
extern int snd_line6_prepare(struct snd_pcm_substream *substream);
extern void line6_pcm_disconnect(struct snd_line6_pcm *line6pcm);
extern int line6_pcm_acquire(struct snd_line6_pcm *line6pcm, int channels);
extern int line6_pcm_release(struct snd_line6_pcm *line6pcm, int channels);
#endif
|
