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Diffstat (limited to '')
-rw-r--r-- | sound/firewire/digi00x/amdtp-dot.c | 418 |
1 files changed, 418 insertions, 0 deletions
diff --git a/sound/firewire/digi00x/amdtp-dot.c b/sound/firewire/digi00x/amdtp-dot.c new file mode 100644 index 000000000..59b86c8d8 --- /dev/null +++ b/sound/firewire/digi00x/amdtp-dot.c @@ -0,0 +1,418 @@ +// 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; +} |