// 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 * Copyright (C) 2012 Damien Zammit */ #include #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, 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 void process_ir_ctx_payloads(struct amdtp_stream *s, const struct pkt_desc *desc, unsigned int count, struct snd_pcm_substream *pcm) { unsigned int pcm_frames = 0; int i; for (i = 0; i < count; ++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); desc = amdtp_stream_next_packet_desc(s, desc); } } static void process_it_ctx_payloads(struct amdtp_stream *s, const struct pkt_desc *desc, unsigned int count, struct snd_pcm_substream *pcm) { unsigned int pcm_frames = 0; int i; for (i = 0; i < count; ++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); desc = amdtp_stream_next_packet_desc(s, desc); } } 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; }