linux/sound/firewire/digi00x/amdtp-dot.c
Takashi Sakamoto 019af5923c ALSA: firewire-digi00x: perform sequence replay for media clock recovery
This commit takes ALSA firewire-digi00x driver to perform sequence replay
for media clock recovery.

All of models in Digidesign digi00x family don't transfer isochronous
packets till receiving isochronous packets. The on-the-fly mode is used
for the purpose. They don't interpret presentation time expressed in syt
field of received CIP, therefore the sequence of the number of data blocks
per packet is important for media clock recovery.

The sequence replay is tested with below models:

* Digidesign Digi 002
* Digidesign Digi 002 Rack
* Digidesign Digi 003
* Digidesign Digi 003 Rack

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20210531025103.17880-5-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2021-06-01 08:19:25 +02:00

419 lines
10 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* amdtp-dot.c - a part of driver for Digidesign Digi 002/003 family
*
* Copyright (c) 2014-2015 Takashi Sakamoto
* Copyright (C) 2012 Robin Gareus <robin@gareus.org>
* Copyright (C) 2012 Damien Zammit <damien@zamaudio.com>
*/
#include <sound/pcm.h>
#include "digi00x.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
/* 3 = MAX(DOT_MIDI_IN_PORTS, DOT_MIDI_OUT_PORTS) + 1. */
#define MAX_MIDI_PORTS 3
/*
* The double-oh-three algorithm was discovered by Robin Gareus and Damien
* Zammit in 2012, with reverse-engineering for Digi 003 Rack.
*/
struct dot_state {
u8 carry;
u8 idx;
unsigned int off;
};
struct amdtp_dot {
unsigned int pcm_channels;
struct dot_state state;
struct snd_rawmidi_substream *midi[MAX_MIDI_PORTS];
int midi_fifo_used[MAX_MIDI_PORTS];
int midi_fifo_limit;
};
/*
* double-oh-three look up table
*
* @param idx index byte (audio-sample data) 0x00..0xff
* @param off channel offset shift
* @return salt to XOR with given data
*/
#define BYTE_PER_SAMPLE (4)
#define MAGIC_DOT_BYTE (2)
#define MAGIC_BYTE_OFF(x) (((x) * BYTE_PER_SAMPLE) + MAGIC_DOT_BYTE)
static u8 dot_scrt(const u8 idx, const unsigned int off)
{
/*
* the length of the added pattern only depends on the lower nibble
* of the last non-zero data
*/
static const u8 len[16] = {0, 1, 3, 5, 7, 9, 11, 13, 14,
12, 10, 8, 6, 4, 2, 0};
/*
* the lower nibble of the salt. Interleaved sequence.
* this is walked backwards according to len[]
*/
static const u8 nib[15] = {0x8, 0x7, 0x9, 0x6, 0xa, 0x5, 0xb, 0x4,
0xc, 0x3, 0xd, 0x2, 0xe, 0x1, 0xf};
/* circular list for the salt's hi nibble. */
static const u8 hir[15] = {0x0, 0x6, 0xf, 0x8, 0x7, 0x5, 0x3, 0x4,
0xc, 0xd, 0xe, 0x1, 0x2, 0xb, 0xa};
/*
* start offset for upper nibble mapping.
* note: 9 is /special/. In the case where the high nibble == 0x9,
* hir[] is not used and - coincidentally - the salt's hi nibble is
* 0x09 regardless of the offset.
*/
static const u8 hio[16] = {0, 11, 12, 6, 7, 5, 1, 4,
3, 0x00, 14, 13, 8, 9, 10, 2};
const u8 ln = idx & 0xf;
const u8 hn = (idx >> 4) & 0xf;
const u8 hr = (hn == 0x9) ? 0x9 : hir[(hio[hn] + off) % 15];
if (len[ln] < off)
return 0x00;
return ((nib[14 + off - len[ln]]) | (hr << 4));
}
static void dot_encode_step(struct dot_state *state, __be32 *const buffer)
{
u8 * const data = (u8 *) buffer;
if (data[MAGIC_DOT_BYTE] != 0x00) {
state->off = 0;
state->idx = data[MAGIC_DOT_BYTE] ^ state->carry;
}
data[MAGIC_DOT_BYTE] ^= state->carry;
state->carry = dot_scrt(state->idx, ++(state->off));
}
int amdtp_dot_set_parameters(struct amdtp_stream *s, unsigned int rate,
unsigned int pcm_channels)
{
struct amdtp_dot *p = s->protocol;
int err;
if (amdtp_stream_running(s))
return -EBUSY;
/*
* A first data channel is for MIDI messages, the rest is Multi Bit
* Linear Audio data channel.
*/
err = amdtp_stream_set_parameters(s, rate, pcm_channels + 1);
if (err < 0)
return err;
s->ctx_data.rx.fdf = AMDTP_FDF_AM824 | s->sfc;
p->pcm_channels = 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;
}
static void write_pcm_s32(struct amdtp_stream *s, struct snd_pcm_substream *pcm,
__be32 *buffer, unsigned int frames,
unsigned int pcm_frames)
{
struct amdtp_dot *p = s->protocol;
unsigned int channels = p->pcm_channels;
struct snd_pcm_runtime *runtime = pcm->runtime;
unsigned int pcm_buffer_pointer;
int remaining_frames;
const u32 *src;
int i, c;
pcm_buffer_pointer = s->pcm_buffer_pointer + pcm_frames;
pcm_buffer_pointer %= runtime->buffer_size;
src = (void *)runtime->dma_area +
frames_to_bytes(runtime, pcm_buffer_pointer);
remaining_frames = runtime->buffer_size - pcm_buffer_pointer;
buffer++;
for (i = 0; i < frames; ++i) {
for (c = 0; c < channels; ++c) {
buffer[c] = cpu_to_be32((*src >> 8) | 0x40000000);
dot_encode_step(&p->state, &buffer[c]);
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,
unsigned int pcm_frames)
{
struct amdtp_dot *p = s->protocol;
unsigned int channels = p->pcm_channels;
struct snd_pcm_runtime *runtime = pcm->runtime;
unsigned int pcm_buffer_pointer;
int remaining_frames;
u32 *dst;
int i, c;
pcm_buffer_pointer = s->pcm_buffer_pointer + pcm_frames;
pcm_buffer_pointer %= runtime->buffer_size;
dst = (void *)runtime->dma_area +
frames_to_bytes(runtime, pcm_buffer_pointer);
remaining_frames = runtime->buffer_size - pcm_buffer_pointer;
buffer++;
for (i = 0; i < frames; ++i) {
for (c = 0; c < channels; ++c) {
*dst = be32_to_cpu(buffer[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 data_blocks)
{
struct amdtp_dot *p = s->protocol;
unsigned int channels, i, c;
channels = p->pcm_channels;
buffer++;
for (i = 0; i < data_blocks; ++i) {
for (c = 0; c < channels; ++c)
buffer[c] = cpu_to_be32(0x40000000);
buffer += s->data_block_quadlets;
}
}
static bool midi_ratelimit_per_packet(struct amdtp_stream *s, unsigned int port)
{
struct amdtp_dot *p = s->protocol;
int used;
used = p->midi_fifo_used[port];
if (used == 0)
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 inline void midi_use_bytes(struct amdtp_stream *s,
unsigned int port, unsigned int count)
{
struct amdtp_dot *p = s->protocol;
p->midi_fifo_used[port] += amdtp_rate_table[s->sfc] * count;
}
static void write_midi_messages(struct amdtp_stream *s, __be32 *buffer,
unsigned int data_blocks, unsigned int data_block_counter)
{
struct amdtp_dot *p = s->protocol;
unsigned int f, port;
int len;
u8 *b;
for (f = 0; f < data_blocks; f++) {
port = (data_block_counter + f) % 8;
b = (u8 *)&buffer[0];
len = 0;
if (port < MAX_MIDI_PORTS &&
midi_ratelimit_per_packet(s, port) &&
p->midi[port] != NULL)
len = snd_rawmidi_transmit(p->midi[port], b + 1, 2);
if (len > 0) {
/*
* Upper 4 bits of LSB represent port number.
* - 0000b: physical MIDI port 1.
* - 0010b: physical MIDI port 2.
* - 1110b: console MIDI port.
*/
if (port == 2)
b[3] = 0xe0;
else if (port == 1)
b[3] = 0x20;
else
b[3] = 0x00;
b[3] |= len;
midi_use_bytes(s, port, len);
} else {
b[1] = 0;
b[2] = 0;
b[3] = 0;
}
b[0] = 0x80;
buffer += s->data_block_quadlets;
}
}
static void read_midi_messages(struct amdtp_stream *s, __be32 *buffer,
unsigned int data_blocks)
{
struct amdtp_dot *p = s->protocol;
unsigned int f, port, len;
u8 *b;
for (f = 0; f < data_blocks; f++) {
b = (u8 *)&buffer[0];
len = b[3] & 0x0f;
if (len > 0) {
/*
* Upper 4 bits of LSB represent port number.
* - 0000b: physical MIDI port 1. Use port 0.
* - 1110b: console MIDI port. Use port 2.
*/
if (b[3] >> 4 > 0)
port = 2;
else
port = 0;
if (port < MAX_MIDI_PORTS && p->midi[port])
snd_rawmidi_receive(p->midi[port], b + 1, len);
}
buffer += s->data_block_quadlets;
}
}
int amdtp_dot_add_pcm_hw_constraints(struct amdtp_stream *s,
struct snd_pcm_runtime *runtime)
{
int err;
/* This protocol delivers 24 bit data in 32bit data channel. */
err = snd_pcm_hw_constraint_msbits(runtime, 0, 32, 24);
if (err < 0)
return err;
return amdtp_stream_add_pcm_hw_constraints(s, runtime);
}
void amdtp_dot_midi_trigger(struct amdtp_stream *s, unsigned int port,
struct snd_rawmidi_substream *midi)
{
struct amdtp_dot *p = s->protocol;
if (port < MAX_MIDI_PORTS)
WRITE_ONCE(p->midi[port], midi);
}
static unsigned int process_ir_ctx_payloads(struct amdtp_stream *s,
const struct pkt_desc *descs,
unsigned int packets,
struct snd_pcm_substream *pcm)
{
unsigned int pcm_frames = 0;
int i;
for (i = 0; i < packets; ++i) {
const struct pkt_desc *desc = descs + i;
__be32 *buf = desc->ctx_payload;
unsigned int data_blocks = desc->data_blocks;
if (pcm) {
read_pcm_s32(s, pcm, buf, data_blocks, pcm_frames);
pcm_frames += data_blocks;
}
read_midi_messages(s, buf, data_blocks);
}
return pcm_frames;
}
static unsigned int process_it_ctx_payloads(struct amdtp_stream *s,
const struct pkt_desc *descs,
unsigned int packets,
struct snd_pcm_substream *pcm)
{
unsigned int pcm_frames = 0;
int i;
for (i = 0; i < packets; ++i) {
const struct pkt_desc *desc = descs + i;
__be32 *buf = desc->ctx_payload;
unsigned int data_blocks = desc->data_blocks;
if (pcm) {
write_pcm_s32(s, pcm, buf, data_blocks, pcm_frames);
pcm_frames += data_blocks;
} else {
write_pcm_silence(s, buf, data_blocks);
}
write_midi_messages(s, buf, data_blocks,
desc->data_block_counter);
}
return pcm_frames;
}
int amdtp_dot_init(struct amdtp_stream *s, struct fw_unit *unit,
enum amdtp_stream_direction dir)
{
amdtp_stream_process_ctx_payloads_t process_ctx_payloads;
unsigned int flags = CIP_NONBLOCKING | CIP_UNAWARE_SYT;
// Use different mode between incoming/outgoing.
if (dir == AMDTP_IN_STREAM)
process_ctx_payloads = process_ir_ctx_payloads;
else
process_ctx_payloads = process_it_ctx_payloads;
return amdtp_stream_init(s, unit, dir, flags, CIP_FMT_AM,
process_ctx_payloads, sizeof(struct amdtp_dot));
}
void amdtp_dot_reset(struct amdtp_stream *s)
{
struct amdtp_dot *p = s->protocol;
p->state.carry = 0x00;
p->state.idx = 0x00;
p->state.off = 0;
}