/*
* AM824 format in Audio and Music Data Transmission Protocol (IEC 61883-6)
*
* Copyright (c) 2015 Takashi Sakamoto <o-takashi@sakamocchi.jp>
*
* Licensed under the terms of the GNU General Public License, version 2.
*/
#include "amdtp-am824.h"
#define CIP_FMT_AM 0x10
/* "Clock-based rate control mode" is just supported. */
#define AMDTP_FDF_AM824 0x00
/**
* amdtp_am824_set_parameters - set stream parameters
* @s: the AMDTP stream to configure
* @rate: the sample rate
* @pcm_channels: the number of PCM samples in each data block, to be encoded
* as AM824 multi-bit linear audio
* @midi_ports: the number of MIDI ports (i.e., MPX-MIDI Data Channels)
* @double_pcm_frames: one data block transfers two PCM frames
*
* The parameters must be set before the stream is started, and must not be
* changed while the stream is running.
*/
int amdtp_am824_set_parameters(struct amdtp_stream *s, unsigned int rate,
unsigned int pcm_channels,
unsigned int midi_ports,
bool double_pcm_frames)
{
int err;
err = amdtp_stream_set_parameters(s, rate, pcm_channels, midi_ports);
if (err < 0)
return err;
s->fdf = AMDTP_FDF_AM824 | s->sfc;
/*
* In IEC 61883-6, one data block represents one event. In ALSA, one
* event equals to one PCM frame. But Dice has a quirk at higher
* sampling rate to transfer two PCM frames in one data block.
*/
if (double_pcm_frames)
s->frame_multiplier = 2;
else
s->frame_multiplier = 1;
return 0;
}
EXPORT_SYMBOL_GPL(amdtp_am824_set_parameters);
/**
* amdtp_am824_set_pcm_position - set an index of data channel for a channel
* of PCM frame
* @s: the AMDTP stream
* @index: the index of data channel in an data block
* @position: the channel of PCM frame
*/
void amdtp_am824_set_pcm_position(struct amdtp_stream *s, unsigned int index,
unsigned int position)
{
if (index < s->pcm_channels)
s->pcm_positions[index] = position;
}
EXPORT_SYMBOL_GPL(amdtp_am824_set_pcm_position);
/**
* amdtp_am824_set_midi_position - set a index of data channel for MIDI
* conformant data channel
* @s: the AMDTP stream
* @position: the index of data channel in an data block
*/
void amdtp_am824_set_midi_position(struct amdtp_stream *s,
unsigned int position)
{
s->midi_position = position;
}
EXPORT_SYMBOL_GPL(amdtp_am824_set_midi_position);
/**
* amdtp_am824_add_pcm_hw_constraints - add hw constraints for PCM substream
* @s: the AMDTP stream for AM824 data block, must be initialized.
* @runtime: the PCM substream runtime
*
*/
int amdtp_am824_add_pcm_hw_constraints(struct amdtp_stream *s,
struct snd_pcm_runtime *runtime)
{
int err;
err = amdtp_stream_add_pcm_hw_constraints(s, runtime);
if (err < 0)
return err;
/* AM824 in IEC 61883-6 can deliver 24bit data. */
return snd_pcm_hw_constraint_msbits(runtime, 0, 32, 24);
}
EXPORT_SYMBOL_GPL(amdtp_am824_add_pcm_hw_constraints);
/**
* amdtp_am824_midi_trigger - start/stop playback/capture with a MIDI device
* @s: the AMDTP stream
* @port: index of MIDI port
* @midi: the MIDI device to be started, or %NULL to stop the current device
*
* Call this function on a running isochronous stream to enable the actual
* transmission of MIDI data. This function should be called from the MIDI
* device's .trigger callback.
*/
void amdtp_am824_midi_trigger(struct amdtp_stream *s, unsigned int port,
struct snd_rawmidi_substream *midi)
{
if (port < s->midi_ports)
ACCESS_ONCE(s->midi[port]) = midi;
}
EXPORT_SYMBOL_GPL(amdtp_am824_midi_trigger);
/**
* amdtp_am824_init - initialize an AMDTP stream structure to handle AM824
* data block
* @s: the AMDTP stream to initialize
* @unit: the target of the stream
* @dir: the direction of stream
* @flags: the packet transmission method to use
*/
int amdtp_am824_init(struct amdtp_stream *s, struct fw_unit *unit,
enum amdtp_stream_direction dir, enum cip_flags flags)
{
return amdtp_stream_init(s, unit, dir, flags, CIP_FMT_AM);
}
EXPORT_SYMBOL_GPL(amdtp_am824_init);
