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 /*
9 PCM interface to POD series devices.
10 */
11
12 #ifndef PCM_H
13 #define PCM_H
14
15 #include <sound/pcm.h>
16
17 #include "driver.h"
18
19 /*
20 number of USB frames per URB
21 The Line 6 Windows driver always transmits two frames per packet, but
22 the Linux driver performs significantly better (i.e., lower latency)
23 with only one frame per packet.
24 */
25 #define LINE6_ISO_PACKETS 1
26
27 /* in a "full speed" device (such as the PODxt Pro) this means 1ms,
28 * for "high speed" it's 1/8ms
29 */
30 #define LINE6_ISO_INTERVAL 1
31
32 #define LINE6_IMPULSE_DEFAULT_PERIOD 100
33
34 /*
35 Get substream from Line 6 PCM data structure
36 */
37 #define get_substream(line6pcm, stream) \
38 (line6pcm->pcm->streams[stream].substream)
39
40 /*
41 PCM mode bits.
42
43 There are several features of the Line 6 USB driver which require PCM
44 data to be exchanged with the device:
45 *) PCM playback and capture via ALSA
46 *) software monitoring (for devices without hardware monitoring)
47 *) optional impulse response measurement
48 However, from the device's point of view, there is just a single
49 capture and playback stream, which must be shared between these
50 subsystems. It is therefore necessary to maintain the state of the
51 subsystems with respect to PCM usage.
52
53 We define two bit flags, "opened" and "running", for each playback
54 or capture stream. Both can contain the bit flag corresponding to
55 LINE6_STREAM_* type,
56 LINE6_STREAM_PCM = ALSA PCM playback or capture
57 LINE6_STREAM_MONITOR = software monitoring
58 IMPULSE = optional impulse response measurement
59 The opened flag indicates whether the buffer is allocated while
60 the running flag indicates whether the stream is running.
61
62 For monitor or impulse operations, the driver needs to call
63 line6_pcm_acquire() or line6_pcm_release() with the appropriate
64 LINE6_STREAM_* flag.
65 */
66
67 /* stream types */
68 enum {
69 LINE6_STREAM_PCM,
70 LINE6_STREAM_MONITOR,
71 LINE6_STREAM_IMPULSE,
72 LINE6_STREAM_CAPTURE_HELPER,
73 };
74
75 /* misc bit flags for PCM operation */
76 enum {
77 LINE6_FLAG_PAUSE_PLAYBACK,
78 LINE6_FLAG_PREPARED,
79 };
80
81 struct line6_pcm_properties {
82 struct snd_pcm_hardware playback_hw, capture_hw;
83 struct snd_pcm_hw_constraint_ratdens rates;
84 int bytes_per_channel;
85 };
86
87 struct line6_pcm_stream {
88 /* allocated URBs */
89 struct urb **urbs;
90
91 /* Temporary buffer;
92 * Since the packet size is not known in advance, this buffer is
93 * large enough to store maximum size packets.
94 */
95 unsigned char *buffer;
96
97 /* Free frame position in the buffer. */
98 snd_pcm_uframes_t pos;
99
100 /* Count processed bytes;
101 * This is modulo period size (to determine when a period is finished).
102 */
103 unsigned bytes;
104
105 /* Counter to create desired sample rate */
106 unsigned count;
107
108 /* period size in bytes */
109 unsigned period;
110
111 /* Processed frame position in the buffer;
112 * The contents of the ring buffer have been consumed by the USB
113 * subsystem (i.e., sent to the USB device) up to this position.
114 */
115 snd_pcm_uframes_t pos_done;
116
117 /* Bit mask of active URBs */
118 unsigned long active_urbs;
119
120 /* Bit mask of URBs currently being unlinked */
121 unsigned long unlink_urbs;
122
123 /* Spin lock to protect updates of the buffer positions (not contents)
124 */
125 spinlock_t lock;
126
127 /* Bit flags for operational stream types */
128 unsigned long opened;
129
130 /* Bit flags for running stream types */
131 unsigned long running;
132
133 int last_frame;
134 };
135
136 struct snd_line6_pcm {
137 /* Pointer back to the Line 6 driver data structure */
138 struct usb_line6 *line6;
139
140 /* Properties. */
141 struct line6_pcm_properties *properties;
142
143 /* ALSA pcm stream */
144 struct snd_pcm *pcm;
145
146 /* protection to state changes of in/out streams */
147 struct mutex state_mutex;
148
149 /* Capture and playback streams */
150 struct line6_pcm_stream in;
151 struct line6_pcm_stream out;
152
153 /* Previously captured frame (for software monitoring) */
154 unsigned char *prev_fbuf;
155
156 /* Size of previously captured frame (for software monitoring/sync) */
157 int prev_fsize;
158
159 /* Maximum size of USB packet */
160 int max_packet_size_in;
161 int max_packet_size_out;
162
163 /* PCM playback volume (left and right) */
164 int volume_playback[2];
165
166 /* PCM monitor volume */
167 int volume_monitor;
168
169 /* Volume of impulse response test signal (if zero, test is disabled) */
170 int impulse_volume;
171
172 /* Period of impulse response test signal */
173 int impulse_period;
174
175 /* Counter for impulse response test signal */
176 int impulse_count;
177
178 /* Several status bits (see LINE6_FLAG_*) */
179 unsigned long flags;
180 };
181
182 extern int line6_init_pcm(struct usb_line6 *line6,
183 struct line6_pcm_properties *properties);
184 extern int snd_line6_trigger(struct snd_pcm_substream *substream, int cmd);
185 extern int snd_line6_prepare(struct snd_pcm_substream *substream);
186 extern int snd_line6_hw_params(struct snd_pcm_substream *substream,
187 struct snd_pcm_hw_params *hw_params);
188 extern int snd_line6_hw_free(struct snd_pcm_substream *substream);
189 extern snd_pcm_uframes_t snd_line6_pointer(struct snd_pcm_substream *substream);
190 extern void line6_pcm_disconnect(struct snd_line6_pcm *line6pcm);
191 extern int line6_pcm_acquire(struct snd_line6_pcm *line6pcm, int type,
192 bool start);
193 extern void line6_pcm_release(struct snd_line6_pcm *line6pcm, int type);
194
195 #endif