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418 lines
10 KiB
418 lines
10 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* amdtp-dot.c - a part of driver for Digidesign Digi 002/003 family |
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* |
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* Copyright (c) 2014-2015 Takashi Sakamoto |
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* Copyright (C) 2012 Robin Gareus <[email protected]> |
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* Copyright (C) 2012 Damien Zammit <[email protected]> |
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*/ |
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#include <sound/pcm.h> |
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#include "digi00x.h" |
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#define CIP_FMT_AM 0x10 |
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/* 'Clock-based rate control mode' is just supported. */ |
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#define AMDTP_FDF_AM824 0x00 |
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/* |
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* Nominally 3125 bytes/second, but the MIDI port's clock might be |
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* 1% too slow, and the bus clock 100 ppm too fast. |
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*/ |
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#define MIDI_BYTES_PER_SECOND 3093 |
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/* |
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* Several devices look only at the first eight data blocks. |
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* In any case, this is more than enough for the MIDI data rate. |
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*/ |
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#define MAX_MIDI_RX_BLOCKS 8 |
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/* 3 = MAX(DOT_MIDI_IN_PORTS, DOT_MIDI_OUT_PORTS) + 1. */ |
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#define MAX_MIDI_PORTS 3 |
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/* |
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* The double-oh-three algorithm was discovered by Robin Gareus and Damien |
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* Zammit in 2012, with reverse-engineering for Digi 003 Rack. |
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*/ |
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struct dot_state { |
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u8 carry; |
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u8 idx; |
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unsigned int off; |
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}; |
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struct amdtp_dot { |
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unsigned int pcm_channels; |
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struct dot_state state; |
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struct snd_rawmidi_substream *midi[MAX_MIDI_PORTS]; |
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int midi_fifo_used[MAX_MIDI_PORTS]; |
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int midi_fifo_limit; |
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}; |
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/* |
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* double-oh-three look up table |
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* |
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* @param idx index byte (audio-sample data) 0x00..0xff |
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* @param off channel offset shift |
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* @return salt to XOR with given data |
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*/ |
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#define BYTE_PER_SAMPLE (4) |
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#define MAGIC_DOT_BYTE (2) |
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#define MAGIC_BYTE_OFF(x) (((x) * BYTE_PER_SAMPLE) + MAGIC_DOT_BYTE) |
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static u8 dot_scrt(const u8 idx, const unsigned int off) |
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{ |
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/* |
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* the length of the added pattern only depends on the lower nibble |
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* of the last non-zero data |
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*/ |
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static const u8 len[16] = {0, 1, 3, 5, 7, 9, 11, 13, 14, |
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12, 10, 8, 6, 4, 2, 0}; |
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/* |
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* the lower nibble of the salt. Interleaved sequence. |
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* this is walked backwards according to len[] |
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*/ |
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static const u8 nib[15] = {0x8, 0x7, 0x9, 0x6, 0xa, 0x5, 0xb, 0x4, |
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0xc, 0x3, 0xd, 0x2, 0xe, 0x1, 0xf}; |
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/* circular list for the salt's hi nibble. */ |
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static const u8 hir[15] = {0x0, 0x6, 0xf, 0x8, 0x7, 0x5, 0x3, 0x4, |
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0xc, 0xd, 0xe, 0x1, 0x2, 0xb, 0xa}; |
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/* |
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* start offset for upper nibble mapping. |
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* note: 9 is /special/. In the case where the high nibble == 0x9, |
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* hir[] is not used and - coincidentally - the salt's hi nibble is |
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* 0x09 regardless of the offset. |
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*/ |
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static const u8 hio[16] = {0, 11, 12, 6, 7, 5, 1, 4, |
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3, 0x00, 14, 13, 8, 9, 10, 2}; |
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const u8 ln = idx & 0xf; |
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const u8 hn = (idx >> 4) & 0xf; |
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const u8 hr = (hn == 0x9) ? 0x9 : hir[(hio[hn] + off) % 15]; |
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if (len[ln] < off) |
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return 0x00; |
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return ((nib[14 + off - len[ln]]) | (hr << 4)); |
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} |
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static void dot_encode_step(struct dot_state *state, __be32 *const buffer) |
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{ |
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u8 * const data = (u8 *) buffer; |
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if (data[MAGIC_DOT_BYTE] != 0x00) { |
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state->off = 0; |
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state->idx = data[MAGIC_DOT_BYTE] ^ state->carry; |
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} |
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data[MAGIC_DOT_BYTE] ^= state->carry; |
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state->carry = dot_scrt(state->idx, ++(state->off)); |
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} |
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int amdtp_dot_set_parameters(struct amdtp_stream *s, unsigned int rate, |
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unsigned int pcm_channels) |
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{ |
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struct amdtp_dot *p = s->protocol; |
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int err; |
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if (amdtp_stream_running(s)) |
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return -EBUSY; |
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/* |
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* A first data channel is for MIDI messages, the rest is Multi Bit |
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* Linear Audio data channel. |
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*/ |
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err = amdtp_stream_set_parameters(s, rate, pcm_channels + 1); |
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if (err < 0) |
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return err; |
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s->ctx_data.rx.fdf = AMDTP_FDF_AM824 | s->sfc; |
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p->pcm_channels = pcm_channels; |
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/* |
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* We do not know the actual MIDI FIFO size of most devices. Just |
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* assume two bytes, i.e., one byte can be received over the bus while |
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* the previous one is transmitted over MIDI. |
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* (The value here is adjusted for midi_ratelimit_per_packet().) |
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*/ |
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p->midi_fifo_limit = rate - MIDI_BYTES_PER_SECOND * s->syt_interval + 1; |
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return 0; |
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} |
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static void write_pcm_s32(struct amdtp_stream *s, struct snd_pcm_substream *pcm, |
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__be32 *buffer, unsigned int frames, |
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unsigned int pcm_frames) |
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{ |
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struct amdtp_dot *p = s->protocol; |
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unsigned int channels = p->pcm_channels; |
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struct snd_pcm_runtime *runtime = pcm->runtime; |
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unsigned int pcm_buffer_pointer; |
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int remaining_frames; |
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const u32 *src; |
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int i, c; |
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pcm_buffer_pointer = s->pcm_buffer_pointer + pcm_frames; |
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pcm_buffer_pointer %= runtime->buffer_size; |
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src = (void *)runtime->dma_area + |
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frames_to_bytes(runtime, pcm_buffer_pointer); |
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remaining_frames = runtime->buffer_size - pcm_buffer_pointer; |
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buffer++; |
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for (i = 0; i < frames; ++i) { |
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for (c = 0; c < channels; ++c) { |
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buffer[c] = cpu_to_be32((*src >> 8) | 0x40000000); |
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dot_encode_step(&p->state, &buffer[c]); |
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src++; |
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} |
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buffer += s->data_block_quadlets; |
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if (--remaining_frames == 0) |
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src = (void *)runtime->dma_area; |
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} |
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} |
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static void read_pcm_s32(struct amdtp_stream *s, struct snd_pcm_substream *pcm, |
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__be32 *buffer, unsigned int frames, |
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unsigned int pcm_frames) |
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{ |
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struct amdtp_dot *p = s->protocol; |
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unsigned int channels = p->pcm_channels; |
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struct snd_pcm_runtime *runtime = pcm->runtime; |
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unsigned int pcm_buffer_pointer; |
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int remaining_frames; |
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u32 *dst; |
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int i, c; |
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pcm_buffer_pointer = s->pcm_buffer_pointer + pcm_frames; |
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pcm_buffer_pointer %= runtime->buffer_size; |
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dst = (void *)runtime->dma_area + |
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frames_to_bytes(runtime, pcm_buffer_pointer); |
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remaining_frames = runtime->buffer_size - pcm_buffer_pointer; |
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buffer++; |
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for (i = 0; i < frames; ++i) { |
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for (c = 0; c < channels; ++c) { |
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*dst = be32_to_cpu(buffer[c]) << 8; |
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dst++; |
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} |
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buffer += s->data_block_quadlets; |
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if (--remaining_frames == 0) |
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dst = (void *)runtime->dma_area; |
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} |
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} |
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static void write_pcm_silence(struct amdtp_stream *s, __be32 *buffer, |
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unsigned int data_blocks) |
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{ |
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struct amdtp_dot *p = s->protocol; |
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unsigned int channels, i, c; |
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channels = p->pcm_channels; |
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buffer++; |
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for (i = 0; i < data_blocks; ++i) { |
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for (c = 0; c < channels; ++c) |
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buffer[c] = cpu_to_be32(0x40000000); |
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buffer += s->data_block_quadlets; |
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} |
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} |
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static bool midi_ratelimit_per_packet(struct amdtp_stream *s, unsigned int port) |
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{ |
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struct amdtp_dot *p = s->protocol; |
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int used; |
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used = p->midi_fifo_used[port]; |
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if (used == 0) |
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return true; |
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used -= MIDI_BYTES_PER_SECOND * s->syt_interval; |
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used = max(used, 0); |
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p->midi_fifo_used[port] = used; |
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return used < p->midi_fifo_limit; |
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} |
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static inline void midi_use_bytes(struct amdtp_stream *s, |
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unsigned int port, unsigned int count) |
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{ |
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struct amdtp_dot *p = s->protocol; |
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p->midi_fifo_used[port] += amdtp_rate_table[s->sfc] * count; |
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} |
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static void write_midi_messages(struct amdtp_stream *s, __be32 *buffer, |
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unsigned int data_blocks, unsigned int data_block_counter) |
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{ |
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struct amdtp_dot *p = s->protocol; |
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unsigned int f, port; |
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int len; |
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u8 *b; |
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for (f = 0; f < data_blocks; f++) { |
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port = (data_block_counter + f) % 8; |
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b = (u8 *)&buffer[0]; |
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len = 0; |
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if (port < MAX_MIDI_PORTS && |
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midi_ratelimit_per_packet(s, port) && |
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p->midi[port] != NULL) |
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len = snd_rawmidi_transmit(p->midi[port], b + 1, 2); |
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if (len > 0) { |
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/* |
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* Upper 4 bits of LSB represent port number. |
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* - 0000b: physical MIDI port 1. |
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* - 0010b: physical MIDI port 2. |
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* - 1110b: console MIDI port. |
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*/ |
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if (port == 2) |
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b[3] = 0xe0; |
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else if (port == 1) |
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b[3] = 0x20; |
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else |
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b[3] = 0x00; |
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b[3] |= len; |
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midi_use_bytes(s, port, len); |
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} else { |
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b[1] = 0; |
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b[2] = 0; |
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b[3] = 0; |
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} |
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b[0] = 0x80; |
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buffer += s->data_block_quadlets; |
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} |
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} |
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static void read_midi_messages(struct amdtp_stream *s, __be32 *buffer, |
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unsigned int data_blocks) |
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{ |
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struct amdtp_dot *p = s->protocol; |
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unsigned int f, port, len; |
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u8 *b; |
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for (f = 0; f < data_blocks; f++) { |
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b = (u8 *)&buffer[0]; |
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len = b[3] & 0x0f; |
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if (len > 0) { |
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/* |
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* Upper 4 bits of LSB represent port number. |
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* - 0000b: physical MIDI port 1. Use port 0. |
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* - 1110b: console MIDI port. Use port 2. |
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*/ |
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if (b[3] >> 4 > 0) |
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port = 2; |
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else |
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port = 0; |
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if (port < MAX_MIDI_PORTS && p->midi[port]) |
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snd_rawmidi_receive(p->midi[port], b + 1, len); |
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} |
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buffer += s->data_block_quadlets; |
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} |
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} |
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int amdtp_dot_add_pcm_hw_constraints(struct amdtp_stream *s, |
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struct snd_pcm_runtime *runtime) |
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{ |
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int err; |
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/* This protocol delivers 24 bit data in 32bit data channel. */ |
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err = snd_pcm_hw_constraint_msbits(runtime, 0, 32, 24); |
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if (err < 0) |
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return err; |
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return amdtp_stream_add_pcm_hw_constraints(s, runtime); |
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} |
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void amdtp_dot_midi_trigger(struct amdtp_stream *s, unsigned int port, |
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struct snd_rawmidi_substream *midi) |
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{ |
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struct amdtp_dot *p = s->protocol; |
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if (port < MAX_MIDI_PORTS) |
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WRITE_ONCE(p->midi[port], midi); |
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} |
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static unsigned int process_ir_ctx_payloads(struct amdtp_stream *s, |
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const struct pkt_desc *descs, |
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unsigned int packets, |
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struct snd_pcm_substream *pcm) |
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{ |
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unsigned int pcm_frames = 0; |
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int i; |
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for (i = 0; i < packets; ++i) { |
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const struct pkt_desc *desc = descs + i; |
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__be32 *buf = desc->ctx_payload; |
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unsigned int data_blocks = desc->data_blocks; |
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if (pcm) { |
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read_pcm_s32(s, pcm, buf, data_blocks, pcm_frames); |
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pcm_frames += data_blocks; |
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} |
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read_midi_messages(s, buf, data_blocks); |
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} |
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return pcm_frames; |
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} |
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static unsigned int process_it_ctx_payloads(struct amdtp_stream *s, |
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const struct pkt_desc *descs, |
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unsigned int packets, |
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struct snd_pcm_substream *pcm) |
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{ |
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unsigned int pcm_frames = 0; |
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int i; |
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for (i = 0; i < packets; ++i) { |
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const struct pkt_desc *desc = descs + i; |
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__be32 *buf = desc->ctx_payload; |
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unsigned int data_blocks = desc->data_blocks; |
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if (pcm) { |
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write_pcm_s32(s, pcm, buf, data_blocks, pcm_frames); |
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pcm_frames += data_blocks; |
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} else { |
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write_pcm_silence(s, buf, data_blocks); |
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} |
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write_midi_messages(s, buf, data_blocks, |
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desc->data_block_counter); |
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} |
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return pcm_frames; |
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} |
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int amdtp_dot_init(struct amdtp_stream *s, struct fw_unit *unit, |
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enum amdtp_stream_direction dir) |
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{ |
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amdtp_stream_process_ctx_payloads_t process_ctx_payloads; |
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unsigned int flags = CIP_NONBLOCKING | CIP_UNAWARE_SYT; |
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// Use different mode between incoming/outgoing. |
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if (dir == AMDTP_IN_STREAM) |
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process_ctx_payloads = process_ir_ctx_payloads; |
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else |
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process_ctx_payloads = process_it_ctx_payloads; |
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return amdtp_stream_init(s, unit, dir, flags, CIP_FMT_AM, |
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process_ctx_payloads, sizeof(struct amdtp_dot)); |
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} |
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void amdtp_dot_reset(struct amdtp_stream *s) |
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{ |
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struct amdtp_dot *p = s->protocol; |
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p->state.carry = 0x00; |
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p->state.idx = 0x00; |
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p->state.off = 0; |
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}
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