linux_dsm_epyc7002/sound/firewire/amdtp-am824.c
Takashi Sakamoto a02cb8f8de ALSA: firewire: remove support for 16 bit PCM samples in playback substream
In IEC 61883-6, AM824 is described as format of data block. In this
format, one data block consists of several data channels, which is aligned
to 32 bit. One data channel has 8 bit label field and 24 bit data field.
PCM frames are transferred in Multi Bit Linear Audio (MBLA) data channel.
This channel can include 16/20/24 bit PCM sample.

As long as I know, models which support IEC 61883-1/6 doesn't allow to
switch bit length of PCM sample in MBLA data channel. They always
transmit/receive PCM frames of 24 bit length. This can be seen for the
other models which support protocols similar to IEC 61883-1/6.

On the other hand, current drivers for these protocols supports 16 bit
length PCM sample in playback substream. In this case, PCM sample is put
into the MBLA data channel with 8 bit padding in LSB side. Although 16
bit PCM sample is major because it's in CD format, this doesn't represent
device capability as is.

This commit removes support for 16 bit PCM samples in playback substream.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Acked-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-05-22 16:24:08 +02:00

399 lines
11 KiB
C

/*
* AM824 format in Audio and Music Data Transmission Protocol (IEC 61883-6)
*
* Copyright (c) Clemens Ladisch <clemens@ladisch.de>
* Copyright (c) 2015 Takashi Sakamoto <o-takashi@sakamocchi.jp>
*
* Licensed under the terms of the GNU General Public License, version 2.
*/
#include <linux/slab.h>
#include "amdtp-am824.h"
#define CIP_FMT_AM 0x10
/* "Clock-based rate control mode" is just supported. */
#define AMDTP_FDF_AM824 0x00
/*
* Nominally 3125 bytes/second, but the MIDI port's clock might be
* 1% too slow, and the bus clock 100 ppm too fast.
*/
#define MIDI_BYTES_PER_SECOND 3093
/*
* Several devices look only at the first eight data blocks.
* In any case, this is more than enough for the MIDI data rate.
*/
#define MAX_MIDI_RX_BLOCKS 8
struct amdtp_am824 {
struct snd_rawmidi_substream *midi[AM824_MAX_CHANNELS_FOR_MIDI * 8];
int midi_fifo_limit;
int midi_fifo_used[AM824_MAX_CHANNELS_FOR_MIDI * 8];
unsigned int pcm_channels;
unsigned int midi_ports;
u8 pcm_positions[AM824_MAX_CHANNELS_FOR_PCM];
u8 midi_position;
unsigned int frame_multiplier;
};
/**
* 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)
{
struct amdtp_am824 *p = s->protocol;
unsigned int midi_channels;
unsigned int i;
int err;
if (amdtp_stream_running(s))
return -EINVAL;
if (pcm_channels > AM824_MAX_CHANNELS_FOR_PCM)
return -EINVAL;
midi_channels = DIV_ROUND_UP(midi_ports, 8);
if (midi_channels > AM824_MAX_CHANNELS_FOR_MIDI)
return -EINVAL;
if (WARN_ON(amdtp_stream_running(s)) ||
WARN_ON(pcm_channels > AM824_MAX_CHANNELS_FOR_PCM) ||
WARN_ON(midi_channels > AM824_MAX_CHANNELS_FOR_MIDI))
return -EINVAL;
err = amdtp_stream_set_parameters(s, rate,
pcm_channels + midi_channels);
if (err < 0)
return err;
s->fdf = AMDTP_FDF_AM824 | s->sfc;
p->pcm_channels = pcm_channels;
p->midi_ports = midi_ports;
/*
* 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)
p->frame_multiplier = 2;
else
p->frame_multiplier = 1;
/* init the position map for PCM and MIDI channels */
for (i = 0; i < pcm_channels; i++)
p->pcm_positions[i] = i;
p->midi_position = p->pcm_channels;
/*
* We do not know the actual MIDI FIFO size of most devices. Just
* assume two bytes, i.e., one byte can be received over the bus while
* the previous one is transmitted over MIDI.
* (The value here is adjusted for midi_ratelimit_per_packet().)
*/
p->midi_fifo_limit = rate - MIDI_BYTES_PER_SECOND * s->syt_interval + 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)
{
struct amdtp_am824 *p = s->protocol;
if (index < p->pcm_channels)
p->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)
{
struct amdtp_am824 *p = s->protocol;
p->midi_position = position;
}
EXPORT_SYMBOL_GPL(amdtp_am824_set_midi_position);
static void write_pcm_s32(struct amdtp_stream *s,
struct snd_pcm_substream *pcm,
__be32 *buffer, unsigned int frames)
{
struct amdtp_am824 *p = s->protocol;
struct snd_pcm_runtime *runtime = pcm->runtime;
unsigned int channels, remaining_frames, i, c;
const u32 *src;
channels = p->pcm_channels;
src = (void *)runtime->dma_area +
frames_to_bytes(runtime, s->pcm_buffer_pointer);
remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer;
for (i = 0; i < frames; ++i) {
for (c = 0; c < channels; ++c) {
buffer[p->pcm_positions[c]] =
cpu_to_be32((*src >> 8) | 0x40000000);
src++;
}
buffer += s->data_block_quadlets;
if (--remaining_frames == 0)
src = (void *)runtime->dma_area;
}
}
static void read_pcm_s32(struct amdtp_stream *s,
struct snd_pcm_substream *pcm,
__be32 *buffer, unsigned int frames)
{
struct amdtp_am824 *p = s->protocol;
struct snd_pcm_runtime *runtime = pcm->runtime;
unsigned int channels, remaining_frames, i, c;
u32 *dst;
channels = p->pcm_channels;
dst = (void *)runtime->dma_area +
frames_to_bytes(runtime, s->pcm_buffer_pointer);
remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer;
for (i = 0; i < frames; ++i) {
for (c = 0; c < channels; ++c) {
*dst = be32_to_cpu(buffer[p->pcm_positions[c]]) << 8;
dst++;
}
buffer += s->data_block_quadlets;
if (--remaining_frames == 0)
dst = (void *)runtime->dma_area;
}
}
static void write_pcm_silence(struct amdtp_stream *s,
__be32 *buffer, unsigned int frames)
{
struct amdtp_am824 *p = s->protocol;
unsigned int i, c, channels = p->pcm_channels;
for (i = 0; i < frames; ++i) {
for (c = 0; c < channels; ++c)
buffer[p->pcm_positions[c]] = cpu_to_be32(0x40000000);
buffer += s->data_block_quadlets;
}
}
/**
* 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)
{
struct amdtp_am824 *p = s->protocol;
if (port < p->midi_ports)
ACCESS_ONCE(p->midi[port]) = midi;
}
EXPORT_SYMBOL_GPL(amdtp_am824_midi_trigger);
/*
* To avoid sending MIDI bytes at too high a rate, assume that the receiving
* device has a FIFO, and track how much it is filled. This values increases
* by one whenever we send one byte in a packet, but the FIFO empties at
* a constant rate independent of our packet rate. One packet has syt_interval
* samples, so the number of bytes that empty out of the FIFO, per packet(!),
* is MIDI_BYTES_PER_SECOND * syt_interval / sample_rate. To avoid storing
* fractional values, the values in midi_fifo_used[] are measured in bytes
* multiplied by the sample rate.
*/
static bool midi_ratelimit_per_packet(struct amdtp_stream *s, unsigned int port)
{
struct amdtp_am824 *p = s->protocol;
int used;
used = p->midi_fifo_used[port];
if (used == 0) /* common shortcut */
return true;
used -= MIDI_BYTES_PER_SECOND * s->syt_interval;
used = max(used, 0);
p->midi_fifo_used[port] = used;
return used < p->midi_fifo_limit;
}
static void midi_rate_use_one_byte(struct amdtp_stream *s, unsigned int port)
{
struct amdtp_am824 *p = s->protocol;
p->midi_fifo_used[port] += amdtp_rate_table[s->sfc];
}
static void write_midi_messages(struct amdtp_stream *s, __be32 *buffer,
unsigned int frames)
{
struct amdtp_am824 *p = s->protocol;
unsigned int f, port;
u8 *b;
for (f = 0; f < frames; f++) {
b = (u8 *)&buffer[p->midi_position];
port = (s->data_block_counter + f) % 8;
if (f < MAX_MIDI_RX_BLOCKS &&
midi_ratelimit_per_packet(s, port) &&
p->midi[port] != NULL &&
snd_rawmidi_transmit(p->midi[port], &b[1], 1) == 1) {
midi_rate_use_one_byte(s, port);
b[0] = 0x81;
} else {
b[0] = 0x80;
b[1] = 0;
}
b[2] = 0;
b[3] = 0;
buffer += s->data_block_quadlets;
}
}
static void read_midi_messages(struct amdtp_stream *s,
__be32 *buffer, unsigned int frames)
{
struct amdtp_am824 *p = s->protocol;
unsigned int f, port;
int len;
u8 *b;
for (f = 0; f < frames; f++) {
port = (s->data_block_counter + f) % 8;
b = (u8 *)&buffer[p->midi_position];
len = b[0] - 0x80;
if ((1 <= len) && (len <= 3) && (p->midi[port]))
snd_rawmidi_receive(p->midi[port], b + 1, len);
buffer += s->data_block_quadlets;
}
}
static unsigned int process_rx_data_blocks(struct amdtp_stream *s, __be32 *buffer,
unsigned int data_blocks, unsigned int *syt)
{
struct amdtp_am824 *p = s->protocol;
struct snd_pcm_substream *pcm = ACCESS_ONCE(s->pcm);
unsigned int pcm_frames;
if (pcm) {
write_pcm_s32(s, pcm, buffer, data_blocks);
pcm_frames = data_blocks * p->frame_multiplier;
} else {
write_pcm_silence(s, buffer, data_blocks);
pcm_frames = 0;
}
if (p->midi_ports)
write_midi_messages(s, buffer, data_blocks);
return pcm_frames;
}
static unsigned int process_tx_data_blocks(struct amdtp_stream *s, __be32 *buffer,
unsigned int data_blocks, unsigned int *syt)
{
struct amdtp_am824 *p = s->protocol;
struct snd_pcm_substream *pcm = ACCESS_ONCE(s->pcm);
unsigned int pcm_frames;
if (pcm) {
read_pcm_s32(s, pcm, buffer, data_blocks);
pcm_frames = data_blocks * p->frame_multiplier;
} else {
pcm_frames = 0;
}
if (p->midi_ports)
read_midi_messages(s, buffer, data_blocks);
return pcm_frames;
}
/**
* 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)
{
amdtp_stream_process_data_blocks_t process_data_blocks;
if (dir == AMDTP_IN_STREAM)
process_data_blocks = process_tx_data_blocks;
else
process_data_blocks = process_rx_data_blocks;
return amdtp_stream_init(s, unit, dir, flags, CIP_FMT_AM,
process_data_blocks,
sizeof(struct amdtp_am824));
}
EXPORT_SYMBOL_GPL(amdtp_am824_init);