sound/usb/line6/pcm.h

   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