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Diffstat (limited to 'sound/usb/line6/pcm.h')
| -rw-r--r-- | sound/usb/line6/pcm.h | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/sound/usb/line6/pcm.h b/sound/usb/line6/pcm.h new file mode 100644 index 000000000..508410adb --- /dev/null +++ b/sound/usb/line6/pcm.h @@ -0,0 +1,197 @@ +/* + * Line 6 Linux USB driver + * + * Copyright (C) 2004-2010 Markus Grabner (grabner@icg.tugraz.at) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation, version 2. + * + */ + +/* + PCM interface to POD series devices. +*/ + +#ifndef PCM_H +#define PCM_H + +#include <sound/pcm.h> + +#include "driver.h" + +/* number of URBs */ +#define LINE6_ISO_BUFFERS 2 + +/* + number of USB frames per URB + The Line 6 Windows driver always transmits two frames per packet, but + the Linux driver performs significantly better (i.e., lower latency) + with only one frame per packet. +*/ +#define LINE6_ISO_PACKETS 1 + +/* in a "full speed" device (such as the PODxt Pro) this means 1ms */ +#define LINE6_ISO_INTERVAL 1 + +#define LINE6_IMPULSE_DEFAULT_PERIOD 100 + +/* + Get substream from Line 6 PCM data structure +*/ +#define get_substream(line6pcm, stream) \ + (line6pcm->pcm->streams[stream].substream) + +/* + PCM mode bits. + + There are several features of the Line 6 USB driver which require PCM + data to be exchanged with the device: + *) PCM playback and capture via ALSA + *) software monitoring (for devices without hardware monitoring) + *) optional impulse response measurement + However, from the device's point of view, there is just a single + capture and playback stream, which must be shared between these + subsystems. It is therefore necessary to maintain the state of the + subsystems with respect to PCM usage. + + We define two bit flags, "opened" and "running", for each playback + or capture stream. Both can contain the bit flag corresponding to + LINE6_STREAM_* type, + LINE6_STREAM_PCM = ALSA PCM playback or capture + LINE6_STREAM_MONITOR = software monitoring + IMPULSE = optional impulse response measurement + The opened flag indicates whether the buffer is allocated while + the running flag indicates whether the stream is running. + + For monitor or impulse operations, the driver needs to call + line6_pcm_acquire() or line6_pcm_release() with the appropriate + LINE6_STREAM_* flag. +*/ + +/* stream types */ +enum { + LINE6_STREAM_PCM, + LINE6_STREAM_MONITOR, + LINE6_STREAM_IMPULSE, +}; + +/* misc bit flags for PCM operation */ +enum { + LINE6_FLAG_PAUSE_PLAYBACK, + LINE6_FLAG_PREPARED, +}; + +struct line6_pcm_properties { + struct snd_pcm_hardware playback_hw, capture_hw; + struct snd_pcm_hw_constraint_ratdens rates; + int bytes_per_frame; +}; + +struct line6_pcm_stream { + /* allocated URBs */ + struct urb *urbs[LINE6_ISO_BUFFERS]; + + /* Temporary buffer; + * Since the packet size is not known in advance, this buffer is + * large enough to store maximum size packets. + */ + unsigned char *buffer; + + /* Free frame position in the buffer. */ + snd_pcm_uframes_t pos; + + /* Count processed bytes; + * This is modulo period size (to determine when a period is finished). + */ + unsigned bytes; + + /* Counter to create desired sample rate */ + unsigned count; + + /* period size in bytes */ + unsigned period; + + /* Processed frame position in the buffer; + * The contents of the ring buffer have been consumed by the USB + * subsystem (i.e., sent to the USB device) up to this position. + */ + snd_pcm_uframes_t pos_done; + + /* Bit mask of active URBs */ + unsigned long active_urbs; + + /* Bit mask of URBs currently being unlinked */ + unsigned long unlink_urbs; + + /* Spin lock to protect updates of the buffer positions (not contents) + */ + spinlock_t lock; + + /* Bit flags for operational stream types */ + unsigned long opened; + + /* Bit flags for running stream types */ + unsigned long running; + + int last_frame; +}; + +struct snd_line6_pcm { + /* Pointer back to the Line 6 driver data structure */ + struct usb_line6 *line6; + + /* Properties. */ + struct line6_pcm_properties *properties; + + /* ALSA pcm stream */ + struct snd_pcm *pcm; + + /* protection to state changes of in/out streams */ + struct mutex state_mutex; + + /* Capture and playback streams */ + struct line6_pcm_stream in; + struct line6_pcm_stream out; + + /* Previously captured frame (for software monitoring) */ + unsigned char *prev_fbuf; + + /* Size of previously captured frame (for software monitoring) */ + int prev_fsize; + + /* Maximum size of USB packet */ + int max_packet_size; + + /* PCM playback volume (left and right) */ + int volume_playback[2]; + + /* PCM monitor volume */ + int volume_monitor; + + /* Volume of impulse response test signal (if zero, test is disabled) */ + int impulse_volume; + + /* Period of impulse response test signal */ + int impulse_period; + + /* Counter for impulse response test signal */ + int impulse_count; + + /* Several status bits (see LINE6_FLAG_*) */ + unsigned long flags; +}; + +extern int line6_init_pcm(struct usb_line6 *line6, + struct line6_pcm_properties *properties); +extern int snd_line6_trigger(struct snd_pcm_substream *substream, int cmd); +extern int snd_line6_prepare(struct snd_pcm_substream *substream); +extern int snd_line6_hw_params(struct snd_pcm_substream *substream, + struct snd_pcm_hw_params *hw_params); +extern int snd_line6_hw_free(struct snd_pcm_substream *substream); +extern snd_pcm_uframes_t snd_line6_pointer(struct snd_pcm_substream *substream); +extern void line6_pcm_disconnect(struct snd_line6_pcm *line6pcm); +extern int line6_pcm_acquire(struct snd_line6_pcm *line6pcm, int type); +extern void line6_pcm_release(struct snd_line6_pcm *line6pcm, int type); + +#endif |