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1/* SPDX-License-Identifier: GPL-2.0-only */2/*3 * Line 6 Linux USB driver4 *5 * Copyright (C) 2004-2010 Markus Grabner (line6@grabner-graz.at)6 */7 8/*9 PCM interface to POD series devices.10*/11 12#ifndef PCM_H13#define PCM_H14 15#include <sound/pcm.h>16 17#include "driver.h"18 19/*20 number of USB frames per URB21 The Line 6 Windows driver always transmits two frames per packet, but22 the Linux driver performs significantly better (i.e., lower latency)23 with only one frame per packet.24*/25#define LINE6_ISO_PACKETS 126 27/* in a "full speed" device (such as the PODxt Pro) this means 1ms,28 * for "high speed" it's 1/8ms29 */30#define LINE6_ISO_INTERVAL 131 32#define LINE6_IMPULSE_DEFAULT_PERIOD 10033 34/*35 Get substream from Line 6 PCM data structure36*/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 PCM44 data to be exchanged with the device:45 *) PCM playback and capture via ALSA46 *) software monitoring (for devices without hardware monitoring)47 *) optional impulse response measurement48 However, from the device's point of view, there is just a single49 capture and playback stream, which must be shared between these50 subsystems. It is therefore necessary to maintain the state of the51 subsystems with respect to PCM usage.52 53 We define two bit flags, "opened" and "running", for each playback54 or capture stream. Both can contain the bit flag corresponding to55 LINE6_STREAM_* type,56 LINE6_STREAM_PCM = ALSA PCM playback or capture57 LINE6_STREAM_MONITOR = software monitoring58 IMPULSE = optional impulse response measurement59 The opened flag indicates whether the buffer is allocated while60 the running flag indicates whether the stream is running.61 62 For monitor or impulse operations, the driver needs to call63 line6_pcm_acquire() or line6_pcm_release() with the appropriate64 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 is93 * 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 USB113 * 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#endif196