cregit-Linux how code gets into the kernel

Release 4.7 sound/firewire/digi00x/amdtp-dot.c

/*
 * 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>
 *
 * Licensed under the terms of the GNU General Public License, version 2.
 */

#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

/*
 * 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;

	
unsigned int midi_ports;
	/* 2 = MAX(DOT_MIDI_IN_PORTS, DOT_MIDI_OUT_PORTS) */
	
struct snd_rawmidi_substream *midi[2];
	
int midi_fifo_used[2];
	
int midi_fifo_limit;

	
void (*transfer_samples)(struct amdtp_stream *s,
				 struct snd_pcm_substream *pcm,
				 __be32 *buffer, unsigned int frames);
};

/*
 * 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)); }

Contributors

PersonTokensPropCommitsCommitProp
takashi sakamototakashi sakamoto264100.00%2100.00%
Total264100.00%2100.00%


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)); }

Contributors

PersonTokensPropCommitsCommitProp
takashi sakamototakashi sakamoto84100.00%2100.00%
Total84100.00%2100.00%


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 conformant data channel, 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->fdf = AMDTP_FDF_AM824 | s->sfc; p->pcm_channels = pcm_channels; if (s->direction == AMDTP_IN_STREAM) p->midi_ports = DOT_MIDI_IN_PORTS; else p->midi_ports = DOT_MIDI_OUT_PORTS; /* * 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; }

Contributors

PersonTokensPropCommitsCommitProp
takashi sakamototakashi sakamoto119100.00%2100.00%
Total119100.00%2100.00%


static void write_pcm_s32(struct amdtp_stream *s, struct snd_pcm_substream *pcm, __be32 *buffer, unsigned int frames) { struct amdtp_dot *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; 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; } }

Contributors

PersonTokensPropCommitsCommitProp
takashi sakamototakashi sakamoto182100.00%1100.00%
Total182100.00%1100.00%


static void write_pcm_s16(struct amdtp_stream *s, struct snd_pcm_substream *pcm, __be32 *buffer, unsigned int frames) { struct amdtp_dot *p = s->protocol; struct snd_pcm_runtime *runtime = pcm->runtime; unsigned int channels, remaining_frames, i, c; const u16 *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; 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; } }

Contributors

PersonTokensPropCommitsCommitProp
takashi sakamototakashi sakamoto182100.00%1100.00%
Total182100.00%1100.00%


static void read_pcm_s32(struct amdtp_stream *s, struct snd_pcm_substream *pcm, __be32 *buffer, unsigned int frames) { struct amdtp_dot *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; 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; } }

Contributors

PersonTokensPropCommitsCommitProp
takashi sakamototakashi sakamoto163100.00%1100.00%
Total163100.00%1100.00%


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; } }

Contributors

PersonTokensPropCommitsCommitProp
takashi sakamototakashi sakamoto89100.00%1100.00%
Total89100.00%1100.00%


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; }

Contributors

PersonTokensPropCommitsCommitProp
takashi sakamototakashi sakamoto78100.00%1100.00%
Total78100.00%1100.00%


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; }

Contributors

PersonTokensPropCommitsCommitProp
takashi sakamototakashi sakamoto45100.00%1100.00%
Total45100.00%1100.00%


static void write_midi_messages(struct amdtp_stream *s, __be32 *buffer, unsigned int data_blocks) { struct amdtp_dot *p = s->protocol; unsigned int f, port; int len; u8 *b; for (f = 0; f < data_blocks; f++) { port = (s->data_block_counter + f) % 8; b = (u8 *)&buffer[0]; len = 0; if (port < p->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) { b[3] = (0x10 << port) | 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; } }

Contributors

PersonTokensPropCommitsCommitProp
takashi sakamototakashi sakamoto193100.00%1100.00%
Total193100.00%1100.00%


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]; port = b[3] >> 4; len = b[3] & 0x0f; if (port < p->midi_ports && p->midi[port] && len > 0) snd_rawmidi_receive(p->midi[port], b + 1, len); buffer += s->data_block_quadlets; } }

Contributors

PersonTokensPropCommitsCommitProp
takashi sakamototakashi sakamoto126100.00%1100.00%
Total126100.00%1100.00%


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); }

Contributors

PersonTokensPropCommitsCommitProp
takashi sakamototakashi sakamoto49100.00%1100.00%
Total49100.00%1100.00%


void amdtp_dot_set_pcm_format(struct amdtp_stream *s, snd_pcm_format_t format) { struct amdtp_dot *p = s->protocol; if (WARN_ON(amdtp_stream_pcm_running(s))) return; switch (format) { default: WARN_ON(1); /* fall through */ case SNDRV_PCM_FORMAT_S16: if (s->direction == AMDTP_OUT_STREAM) { p->transfer_samples = write_pcm_s16; break; } WARN_ON(1); /* fall through */ case SNDRV_PCM_FORMAT_S32: if (s->direction == AMDTP_OUT_STREAM) p->transfer_samples = write_pcm_s32; else p->transfer_samples = read_pcm_s32; break; } }

Contributors

PersonTokensPropCommitsCommitProp
takashi sakamototakashi sakamoto97100.00%1100.00%
Total97100.00%1100.00%


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 < p->midi_ports) ACCESS_ONCE(p->midi[port]) = midi; }

Contributors

PersonTokensPropCommitsCommitProp
takashi sakamototakashi sakamoto48100.00%1100.00%
Total48100.00%1100.00%


static unsigned int process_tx_data_blocks(struct amdtp_stream *s, __be32 *buffer, unsigned int data_blocks, unsigned int *syt) { struct amdtp_dot *p = (struct amdtp_dot *)s->protocol; struct snd_pcm_substream *pcm; unsigned int pcm_frames; pcm = ACCESS_ONCE(s->pcm); if (pcm) { p->transfer_samples(s, pcm, buffer, data_blocks); pcm_frames = data_blocks; } else { pcm_frames = 0; } read_midi_messages(s, buffer, data_blocks); return pcm_frames; }

Contributors

PersonTokensPropCommitsCommitProp
takashi sakamototakashi sakamoto99100.00%2100.00%
Total99100.00%2100.00%


static unsigned int process_rx_data_blocks(struct amdtp_stream *s, __be32 *buffer, unsigned int data_blocks, unsigned int *syt) { struct amdtp_dot *p = (struct amdtp_dot *)s->protocol; struct snd_pcm_substream *pcm; unsigned int pcm_frames; pcm = ACCESS_ONCE(s->pcm); if (pcm) { p->transfer_samples(s, pcm, buffer, data_blocks); pcm_frames = data_blocks; } else { write_pcm_silence(s, buffer, data_blocks); pcm_frames = 0; } write_midi_messages(s, buffer, data_blocks); return pcm_frames; }

Contributors

PersonTokensPropCommitsCommitProp
takashi sakamototakashi sakamoto108100.00%2100.00%
Total108100.00%2100.00%


int amdtp_dot_init(struct amdtp_stream *s, struct fw_unit *unit, enum amdtp_stream_direction dir) { amdtp_stream_process_data_blocks_t process_data_blocks; enum cip_flags flags; /* Use different mode between incoming/outgoing. */ if (dir == AMDTP_IN_STREAM) { flags = CIP_NONBLOCKING; process_data_blocks = process_tx_data_blocks; } else { flags = CIP_BLOCKING; process_data_blocks = process_rx_data_blocks; } return amdtp_stream_init(s, unit, dir, flags, CIP_FMT_AM, process_data_blocks, sizeof(struct amdtp_dot)); }

Contributors

PersonTokensPropCommitsCommitProp
takashi sakamototakashi sakamoto76100.00%1100.00%
Total76100.00%1100.00%


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; }

Contributors

PersonTokensPropCommitsCommitProp
takashi sakamototakashi sakamoto43100.00%1100.00%
Total43100.00%1100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
takashi sakamototakashi sakamoto2163100.00%3100.00%
Total2163100.00%3100.00%
Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.
{% endraw %}