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-rw-r--r--sound/usb/line6/pcm.h197
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diff --git a/sound/usb/line6/pcm.h b/sound/usb/line6/pcm.h
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1/*
2 * Line 6 Linux USB driver
3 *
4 * Copyright (C) 2004-2010 Markus Grabner (grabner@icg.tugraz.at)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License as
8 * published by the Free Software Foundation, version 2.
9 *
10 */
11
12/*
13 PCM interface to POD series devices.
14*/
15
16#ifndef PCM_H
17#define PCM_H
18
19#include <sound/pcm.h>
20
21#include "driver.h"
22
23/* number of URBs */
24#define LINE6_ISO_BUFFERS 2
25
26/*
27 number of USB frames per URB
28 The Line 6 Windows driver always transmits two frames per packet, but
29 the Linux driver performs significantly better (i.e., lower latency)
30 with only one frame per packet.
31*/
32#define LINE6_ISO_PACKETS 1
33
34/* in a "full speed" device (such as the PODxt Pro) this means 1ms */
35#define LINE6_ISO_INTERVAL 1
36
37#define LINE6_IMPULSE_DEFAULT_PERIOD 100
38
39/*
40 Get substream from Line 6 PCM data structure
41*/
42#define get_substream(line6pcm, stream) \
43 (line6pcm->pcm->streams[stream].substream)
44
45/*
46 PCM mode bits.
47
48 There are several features of the Line 6 USB driver which require PCM
49 data to be exchanged with the device:
50 *) PCM playback and capture via ALSA
51 *) software monitoring (for devices without hardware monitoring)
52 *) optional impulse response measurement
53 However, from the device's point of view, there is just a single
54 capture and playback stream, which must be shared between these
55 subsystems. It is therefore necessary to maintain the state of the
56 subsystems with respect to PCM usage.
57
58 We define two bit flags, "opened" and "running", for each playback
59 or capture stream. Both can contain the bit flag corresponding to
60 LINE6_STREAM_* type,
61 LINE6_STREAM_PCM = ALSA PCM playback or capture
62 LINE6_STREAM_MONITOR = software monitoring
63 IMPULSE = optional impulse response measurement
64 The opened flag indicates whether the buffer is allocated while
65 the running flag indicates whether the stream is running.
66
67 For monitor or impulse operations, the driver needs to call
68 line6_pcm_acquire() or line6_pcm_release() with the appropriate
69 LINE6_STREAM_* flag.
70*/
71
72/* stream types */
73enum {
74 LINE6_STREAM_PCM,
75 LINE6_STREAM_MONITOR,
76 LINE6_STREAM_IMPULSE,
77};
78
79/* misc bit flags for PCM operation */
80enum {
81 LINE6_FLAG_PAUSE_PLAYBACK,
82 LINE6_FLAG_PREPARED,
83};
84
85struct line6_pcm_properties {
86 struct snd_pcm_hardware playback_hw, capture_hw;
87 struct snd_pcm_hw_constraint_ratdens rates;
88 int bytes_per_frame;
89};
90
91struct line6_pcm_stream {
92 /* allocated URBs */
93 struct urb *urbs[LINE6_ISO_BUFFERS];
94
95 /* Temporary buffer;
96 * Since the packet size is not known in advance, this buffer is
97 * large enough to store maximum size packets.
98 */
99 unsigned char *buffer;
100
101 /* Free frame position in the buffer. */
102 snd_pcm_uframes_t pos;
103
104 /* Count processed bytes;
105 * This is modulo period size (to determine when a period is finished).
106 */
107 unsigned bytes;
108
109 /* Counter to create desired sample rate */
110 unsigned count;
111
112 /* period size in bytes */
113 unsigned period;
114
115 /* Processed frame position in the buffer;
116 * The contents of the ring buffer have been consumed by the USB
117 * subsystem (i.e., sent to the USB device) up to this position.
118 */
119 snd_pcm_uframes_t pos_done;
120
121 /* Bit mask of active URBs */
122 unsigned long active_urbs;
123
124 /* Bit mask of URBs currently being unlinked */
125 unsigned long unlink_urbs;
126
127 /* Spin lock to protect updates of the buffer positions (not contents)
128 */
129 spinlock_t lock;
130
131 /* Bit flags for operational stream types */
132 unsigned long opened;
133
134 /* Bit flags for running stream types */
135 unsigned long running;
136
137 int last_frame;
138};
139
140struct snd_line6_pcm {
141 /* Pointer back to the Line 6 driver data structure */
142 struct usb_line6 *line6;
143
144 /* Properties. */
145 struct line6_pcm_properties *properties;
146
147 /* ALSA pcm stream */
148 struct snd_pcm *pcm;
149
150 /* protection to state changes of in/out streams */
151 struct mutex state_mutex;
152
153 /* Capture and playback streams */
154 struct line6_pcm_stream in;
155 struct line6_pcm_stream out;
156
157 /* Previously captured frame (for software monitoring) */
158 unsigned char *prev_fbuf;
159
160 /* Size of previously captured frame (for software monitoring) */
161 int prev_fsize;
162
163 /* Maximum size of USB packet */
164 int max_packet_size;
165
166 /* PCM playback volume (left and right) */
167 int volume_playback[2];
168
169 /* PCM monitor volume */
170 int volume_monitor;
171
172 /* Volume of impulse response test signal (if zero, test is disabled) */
173 int impulse_volume;
174
175 /* Period of impulse response test signal */
176 int impulse_period;
177
178 /* Counter for impulse response test signal */
179 int impulse_count;
180
181 /* Several status bits (see LINE6_FLAG_*) */
182 unsigned long flags;
183};
184
185extern int line6_init_pcm(struct usb_line6 *line6,
186 struct line6_pcm_properties *properties);
187extern int snd_line6_trigger(struct snd_pcm_substream *substream, int cmd);
188extern int snd_line6_prepare(struct snd_pcm_substream *substream);
189extern int snd_line6_hw_params(struct snd_pcm_substream *substream,
190 struct snd_pcm_hw_params *hw_params);
191extern int snd_line6_hw_free(struct snd_pcm_substream *substream);
192extern snd_pcm_uframes_t snd_line6_pointer(struct snd_pcm_substream *substream);
193extern void line6_pcm_disconnect(struct snd_line6_pcm *line6pcm);
194extern int line6_pcm_acquire(struct snd_line6_pcm *line6pcm, int type);
195extern void line6_pcm_release(struct snd_line6_pcm *line6pcm, int type);
196
197#endif
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