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 /* 24 number of USB frames per URB 25 The Line 6 Windows driver always transmits two frames per packet, but 26 the Linux driver performs significantly better (i.e., lower latency) 27 with only one frame per packet. 28 */ 29 #define LINE6_ISO_PACKETS 1 30 31 /* in a "full speed" device (such as the PODxt Pro) this means 1ms, 32 * for "high speed" it's 1/8ms 33 */ 34 #define LINE6_ISO_INTERVAL 1 35 36 #define LINE6_IMPULSE_DEFAULT_PERIOD 100 37 38 /* 39 Get substream from Line 6 PCM data structure 40 */ 41 #define get_substream(line6pcm, stream) \ 42 (line6pcm->pcm->streams[stream].substream) 43 44 /* 45 PCM mode bits. 46 47 There are several features of the Line 6 USB driver which require PCM 48 data to be exchanged with the device: 49 *) PCM playback and capture via ALSA 50 *) software monitoring (for devices without hardware monitoring) 51 *) optional impulse response measurement 52 However, from the device's point of view, there is just a single 53 capture and playback stream, which must be shared between these 54 subsystems. It is therefore necessary to maintain the state of the 55 subsystems with respect to PCM usage. 56 57 We define two bit flags, "opened" and "running", for each playback 58 or capture stream. Both can contain the bit flag corresponding to 59 LINE6_STREAM_* type, 60 LINE6_STREAM_PCM = ALSA PCM playback or capture 61 LINE6_STREAM_MONITOR = software monitoring 62 IMPULSE = optional impulse response measurement 63 The opened flag indicates whether the buffer is allocated while 64 the running flag indicates whether the stream is running. 65 66 For monitor or impulse operations, the driver needs to call 67 line6_pcm_acquire() or line6_pcm_release() with the appropriate 68 LINE6_STREAM_* flag. 69 */ 70 71 /* stream types */ 72 enum { 73 LINE6_STREAM_PCM, 74 LINE6_STREAM_MONITOR, 75 LINE6_STREAM_IMPULSE, 76 LINE6_STREAM_CAPTURE_HELPER, 77 }; 78 79 /* misc bit flags for PCM operation */ 80 enum { 81 LINE6_FLAG_PAUSE_PLAYBACK, 82 LINE6_FLAG_PREPARED, 83 }; 84 85 struct line6_pcm_properties { 86 struct snd_pcm_hardware playback_hw, capture_hw; 87 struct snd_pcm_hw_constraint_ratdens rates; 88 int bytes_per_channel; 89 }; 90 91 struct line6_pcm_stream { 92 /* allocated URBs */ 93 struct urb **urbs; 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 }; 139 140 struct 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/sync) */ 161 int prev_fsize; 162 163 /* Maximum size of USB packet */ 164 int max_packet_size_in; 165 int max_packet_size_out; 166 167 /* PCM playback volume (left and right) */ 168 int volume_playback[2]; 169 170 /* PCM monitor volume */ 171 int volume_monitor; 172 173 /* Volume of impulse response test signal (if zero, test is disabled) */ 174 int impulse_volume; 175 176 /* Period of impulse response test signal */ 177 int impulse_period; 178 179 /* Counter for impulse response test signal */ 180 int impulse_count; 181 182 /* Several status bits (see LINE6_FLAG_*) */ 183 unsigned long flags; 184 }; 185 186 extern int line6_init_pcm(struct usb_line6 *line6, 187 struct line6_pcm_properties *properties); 188 extern int snd_line6_trigger(struct snd_pcm_substream *substream, int cmd); 189 extern int snd_line6_prepare(struct snd_pcm_substream *substream); 190 extern int snd_line6_hw_params(struct snd_pcm_substream *substream, 191 struct snd_pcm_hw_params *hw_params); 192 extern int snd_line6_hw_free(struct snd_pcm_substream *substream); 193 extern snd_pcm_uframes_t snd_line6_pointer(struct snd_pcm_substream *substream); 194 extern void line6_pcm_disconnect(struct snd_line6_pcm *line6pcm); 195 extern int line6_pcm_acquire(struct snd_line6_pcm *line6pcm, int type, 196 bool start); 197 extern void line6_pcm_release(struct snd_line6_pcm *line6pcm, int type); 198 199 #endif 200