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
198