LXR linux/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 */
  68enum {
  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 */
  76enum {
  77        LINE6_FLAG_PAUSE_PLAYBACK,
  78        LINE6_FLAG_PREPARED,
  79};
  80
  81struct 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
  87struct 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
 136struct 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
 182extern int line6_init_pcm(struct usb_line6 *line6,
 183                          struct line6_pcm_properties *properties);
 184extern int snd_line6_trigger(struct snd_pcm_substream *substream, int cmd);
 185extern int snd_line6_prepare(struct snd_pcm_substream *substream);
 186extern int snd_line6_hw_params(struct snd_pcm_substream *substream,
 187                               struct snd_pcm_hw_params *hw_params);
 188extern int snd_line6_hw_free(struct snd_pcm_substream *substream);
 189extern snd_pcm_uframes_t snd_line6_pointer(struct snd_pcm_substream *substream);
 190extern void line6_pcm_disconnect(struct snd_line6_pcm *line6pcm);
 191extern int line6_pcm_acquire(struct snd_line6_pcm *line6pcm, int type,
 192                               bool start);
 193extern void line6_pcm_release(struct snd_line6_pcm *line6pcm, int type);
 194
 195#endif
 196