| 1 | /* |
| 2 | * amdtp-dot.c - a part of driver for Digidesign Digi 002/003 family |
| 3 | * |
| 4 | * Copyright (c) 2014-2015 Takashi Sakamoto |
| 5 | * Copyright (C) 2012 Robin Gareus <robin@gareus.org> |
| 6 | * Copyright (C) 2012 Damien Zammit <damien@zamaudio.com> |
| 7 | * |
| 8 | * Licensed under the terms of the GNU General Public License, version 2. |
| 9 | */ |
| 10 | |
| 11 | #include <sound/pcm.h> |
| 12 | #include "digi00x.h" |
| 13 | |
| 14 | #define CIP_FMT_AM 0x10 |
| 15 | |
| 16 | /* 'Clock-based rate control mode' is just supported. */ |
| 17 | #define AMDTP_FDF_AM824 0x00 |
| 18 | |
| 19 | /* |
| 20 | * Nominally 3125 bytes/second, but the MIDI port's clock might be |
| 21 | * 1% too slow, and the bus clock 100 ppm too fast. |
| 22 | */ |
| 23 | #define MIDI_BYTES_PER_SECOND 3093 |
| 24 | |
| 25 | /* |
| 26 | * Several devices look only at the first eight data blocks. |
| 27 | * In any case, this is more than enough for the MIDI data rate. |
| 28 | */ |
| 29 | #define MAX_MIDI_RX_BLOCKS 8 |
| 30 | |
| 31 | /* 3 = MAX(DOT_MIDI_IN_PORTS, DOT_MIDI_OUT_PORTS) + 1. */ |
| 32 | #define MAX_MIDI_PORTS 3 |
| 33 | |
| 34 | /* |
| 35 | * The double-oh-three algorithm was discovered by Robin Gareus and Damien |
| 36 | * Zammit in 2012, with reverse-engineering for Digi 003 Rack. |
| 37 | */ |
| 38 | struct dot_state { |
| 39 | u8 carry; |
| 40 | u8 idx; |
| 41 | unsigned int off; |
| 42 | }; |
| 43 | |
| 44 | struct amdtp_dot { |
| 45 | unsigned int pcm_channels; |
| 46 | struct dot_state state; |
| 47 | |
| 48 | struct snd_rawmidi_substream *midi[MAX_MIDI_PORTS]; |
| 49 | int midi_fifo_used[MAX_MIDI_PORTS]; |
| 50 | int midi_fifo_limit; |
| 51 | }; |
| 52 | |
| 53 | /* |
| 54 | * double-oh-three look up table |
| 55 | * |
| 56 | * @param idx index byte (audio-sample data) 0x00..0xff |
| 57 | * @param off channel offset shift |
| 58 | * @return salt to XOR with given data |
| 59 | */ |
| 60 | #define BYTE_PER_SAMPLE (4) |
| 61 | #define MAGIC_DOT_BYTE (2) |
| 62 | #define MAGIC_BYTE_OFF(x) (((x) * BYTE_PER_SAMPLE) + MAGIC_DOT_BYTE) |
| 63 | static u8 dot_scrt(const u8 idx, const unsigned int off) |
| 64 | { |
| 65 | /* |
| 66 | * the length of the added pattern only depends on the lower nibble |
| 67 | * of the last non-zero data |
| 68 | */ |
| 69 | static const u8 len[16] = {0, 1, 3, 5, 7, 9, 11, 13, 14, |
| 70 | 12, 10, 8, 6, 4, 2, 0}; |
| 71 | |
| 72 | /* |
| 73 | * the lower nibble of the salt. Interleaved sequence. |
| 74 | * this is walked backwards according to len[] |
| 75 | */ |
| 76 | static const u8 nib[15] = {0x8, 0x7, 0x9, 0x6, 0xa, 0x5, 0xb, 0x4, |
| 77 | 0xc, 0x3, 0xd, 0x2, 0xe, 0x1, 0xf}; |
| 78 | |
| 79 | /* circular list for the salt's hi nibble. */ |
| 80 | static const u8 hir[15] = {0x0, 0x6, 0xf, 0x8, 0x7, 0x5, 0x3, 0x4, |
| 81 | 0xc, 0xd, 0xe, 0x1, 0x2, 0xb, 0xa}; |
| 82 | |
| 83 | /* |
| 84 | * start offset for upper nibble mapping. |
| 85 | * note: 9 is /special/. In the case where the high nibble == 0x9, |
| 86 | * hir[] is not used and - coincidentally - the salt's hi nibble is |
| 87 | * 0x09 regardless of the offset. |
| 88 | */ |
| 89 | static const u8 hio[16] = {0, 11, 12, 6, 7, 5, 1, 4, |
| 90 | 3, 0x00, 14, 13, 8, 9, 10, 2}; |
| 91 | |
| 92 | const u8 ln = idx & 0xf; |
| 93 | const u8 hn = (idx >> 4) & 0xf; |
| 94 | const u8 hr = (hn == 0x9) ? 0x9 : hir[(hio[hn] + off) % 15]; |
| 95 | |
| 96 | if (len[ln] < off) |
| 97 | return 0x00; |
| 98 | |
| 99 | return ((nib[14 + off - len[ln]]) | (hr << 4)); |
| 100 | } |
| 101 | |
| 102 | static void dot_encode_step(struct dot_state *state, __be32 *const buffer) |
| 103 | { |
| 104 | u8 * const data = (u8 *) buffer; |
| 105 | |
| 106 | if (data[MAGIC_DOT_BYTE] != 0x00) { |
| 107 | state->off = 0; |
| 108 | state->idx = data[MAGIC_DOT_BYTE] ^ state->carry; |
| 109 | } |
| 110 | data[MAGIC_DOT_BYTE] ^= state->carry; |
| 111 | state->carry = dot_scrt(state->idx, ++(state->off)); |
| 112 | } |
| 113 | |
| 114 | int amdtp_dot_set_parameters(struct amdtp_stream *s, unsigned int rate, |
| 115 | unsigned int pcm_channels) |
| 116 | { |
| 117 | struct amdtp_dot *p = s->protocol; |
| 118 | int err; |
| 119 | |
| 120 | if (amdtp_stream_running(s)) |
| 121 | return -EBUSY; |
| 122 | |
| 123 | /* |
| 124 | * A first data channel is for MIDI messages, the rest is Multi Bit |
| 125 | * Linear Audio data channel. |
| 126 | */ |
| 127 | err = amdtp_stream_set_parameters(s, rate, pcm_channels + 1); |
| 128 | if (err < 0) |
| 129 | return err; |
| 130 | |
| 131 | s->fdf = AMDTP_FDF_AM824 | s->sfc; |
| 132 | |
| 133 | p->pcm_channels = pcm_channels; |
| 134 | |
| 135 | /* |
| 136 | * We do not know the actual MIDI FIFO size of most devices. Just |
| 137 | * assume two bytes, i.e., one byte can be received over the bus while |
| 138 | * the previous one is transmitted over MIDI. |
| 139 | * (The value here is adjusted for midi_ratelimit_per_packet().) |
| 140 | */ |
| 141 | p->midi_fifo_limit = rate - MIDI_BYTES_PER_SECOND * s->syt_interval + 1; |
| 142 | |
| 143 | return 0; |
| 144 | } |
| 145 | |
| 146 | static void write_pcm_s32(struct amdtp_stream *s, struct snd_pcm_substream *pcm, |
| 147 | __be32 *buffer, unsigned int frames) |
| 148 | { |
| 149 | struct amdtp_dot *p = s->protocol; |
| 150 | struct snd_pcm_runtime *runtime = pcm->runtime; |
| 151 | unsigned int channels, remaining_frames, i, c; |
| 152 | const u32 *src; |
| 153 | |
| 154 | channels = p->pcm_channels; |
| 155 | src = (void *)runtime->dma_area + |
| 156 | frames_to_bytes(runtime, s->pcm_buffer_pointer); |
| 157 | remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer; |
| 158 | |
| 159 | buffer++; |
| 160 | for (i = 0; i < frames; ++i) { |
| 161 | for (c = 0; c < channels; ++c) { |
| 162 | buffer[c] = cpu_to_be32((*src >> 8) | 0x40000000); |
| 163 | dot_encode_step(&p->state, &buffer[c]); |
| 164 | src++; |
| 165 | } |
| 166 | buffer += s->data_block_quadlets; |
| 167 | if (--remaining_frames == 0) |
| 168 | src = (void *)runtime->dma_area; |
| 169 | } |
| 170 | } |
| 171 | |
| 172 | static void read_pcm_s32(struct amdtp_stream *s, struct snd_pcm_substream *pcm, |
| 173 | __be32 *buffer, unsigned int frames) |
| 174 | { |
| 175 | struct amdtp_dot *p = s->protocol; |
| 176 | struct snd_pcm_runtime *runtime = pcm->runtime; |
| 177 | unsigned int channels, remaining_frames, i, c; |
| 178 | u32 *dst; |
| 179 | |
| 180 | channels = p->pcm_channels; |
| 181 | dst = (void *)runtime->dma_area + |
| 182 | frames_to_bytes(runtime, s->pcm_buffer_pointer); |
| 183 | remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer; |
| 184 | |
| 185 | buffer++; |
| 186 | for (i = 0; i < frames; ++i) { |
| 187 | for (c = 0; c < channels; ++c) { |
| 188 | *dst = be32_to_cpu(buffer[c]) << 8; |
| 189 | dst++; |
| 190 | } |
| 191 | buffer += s->data_block_quadlets; |
| 192 | if (--remaining_frames == 0) |
| 193 | dst = (void *)runtime->dma_area; |
| 194 | } |
| 195 | } |
| 196 | |
| 197 | static void write_pcm_silence(struct amdtp_stream *s, __be32 *buffer, |
| 198 | unsigned int data_blocks) |
| 199 | { |
| 200 | struct amdtp_dot *p = s->protocol; |
| 201 | unsigned int channels, i, c; |
| 202 | |
| 203 | channels = p->pcm_channels; |
| 204 | |
| 205 | buffer++; |
| 206 | for (i = 0; i < data_blocks; ++i) { |
| 207 | for (c = 0; c < channels; ++c) |
| 208 | buffer[c] = cpu_to_be32(0x40000000); |
| 209 | buffer += s->data_block_quadlets; |
| 210 | } |
| 211 | } |
| 212 | |
| 213 | static bool midi_ratelimit_per_packet(struct amdtp_stream *s, unsigned int port) |
| 214 | { |
| 215 | struct amdtp_dot *p = s->protocol; |
| 216 | int used; |
| 217 | |
| 218 | used = p->midi_fifo_used[port]; |
| 219 | if (used == 0) |
| 220 | return true; |
| 221 | |
| 222 | used -= MIDI_BYTES_PER_SECOND * s->syt_interval; |
| 223 | used = max(used, 0); |
| 224 | p->midi_fifo_used[port] = used; |
| 225 | |
| 226 | return used < p->midi_fifo_limit; |
| 227 | } |
| 228 | |
| 229 | static inline void midi_use_bytes(struct amdtp_stream *s, |
| 230 | unsigned int port, unsigned int count) |
| 231 | { |
| 232 | struct amdtp_dot *p = s->protocol; |
| 233 | |
| 234 | p->midi_fifo_used[port] += amdtp_rate_table[s->sfc] * count; |
| 235 | } |
| 236 | |
| 237 | static void write_midi_messages(struct amdtp_stream *s, __be32 *buffer, |
| 238 | unsigned int data_blocks) |
| 239 | { |
| 240 | struct amdtp_dot *p = s->protocol; |
| 241 | unsigned int f, port; |
| 242 | int len; |
| 243 | u8 *b; |
| 244 | |
| 245 | for (f = 0; f < data_blocks; f++) { |
| 246 | port = (s->data_block_counter + f) % 8; |
| 247 | b = (u8 *)&buffer[0]; |
| 248 | |
| 249 | len = 0; |
| 250 | if (port < MAX_MIDI_PORTS && |
| 251 | midi_ratelimit_per_packet(s, port) && |
| 252 | p->midi[port] != NULL) |
| 253 | len = snd_rawmidi_transmit(p->midi[port], b + 1, 2); |
| 254 | |
| 255 | if (len > 0) { |
| 256 | /* |
| 257 | * Upper 4 bits of LSB represent port number. |
| 258 | * - 0000b: physical MIDI port 1. |
| 259 | * - 0010b: physical MIDI port 2. |
| 260 | * - 1110b: console MIDI port. |
| 261 | */ |
| 262 | if (port == 2) |
| 263 | b[3] = 0xe0; |
| 264 | else if (port == 1) |
| 265 | b[3] = 0x20; |
| 266 | else |
| 267 | b[3] = 0x00; |
| 268 | b[3] |= len; |
| 269 | midi_use_bytes(s, port, len); |
| 270 | } else { |
| 271 | b[1] = 0; |
| 272 | b[2] = 0; |
| 273 | b[3] = 0; |
| 274 | } |
| 275 | b[0] = 0x80; |
| 276 | |
| 277 | buffer += s->data_block_quadlets; |
| 278 | } |
| 279 | } |
| 280 | |
| 281 | static void read_midi_messages(struct amdtp_stream *s, __be32 *buffer, |
| 282 | unsigned int data_blocks) |
| 283 | { |
| 284 | struct amdtp_dot *p = s->protocol; |
| 285 | unsigned int f, port, len; |
| 286 | u8 *b; |
| 287 | |
| 288 | for (f = 0; f < data_blocks; f++) { |
| 289 | b = (u8 *)&buffer[0]; |
| 290 | |
| 291 | len = b[3] & 0x0f; |
| 292 | if (len > 0) { |
| 293 | /* |
| 294 | * Upper 4 bits of LSB represent port number. |
| 295 | * - 0000b: physical MIDI port 1. Use port 0. |
| 296 | * - 1110b: console MIDI port. Use port 2. |
| 297 | */ |
| 298 | if (b[3] >> 4 > 0) |
| 299 | port = 2; |
| 300 | else |
| 301 | port = 0; |
| 302 | |
| 303 | if (port < MAX_MIDI_PORTS && p->midi[port]) |
| 304 | snd_rawmidi_receive(p->midi[port], b + 1, len); |
| 305 | } |
| 306 | |
| 307 | buffer += s->data_block_quadlets; |
| 308 | } |
| 309 | } |
| 310 | |
| 311 | int amdtp_dot_add_pcm_hw_constraints(struct amdtp_stream *s, |
| 312 | struct snd_pcm_runtime *runtime) |
| 313 | { |
| 314 | int err; |
| 315 | |
| 316 | /* This protocol delivers 24 bit data in 32bit data channel. */ |
| 317 | err = snd_pcm_hw_constraint_msbits(runtime, 0, 32, 24); |
| 318 | if (err < 0) |
| 319 | return err; |
| 320 | |
| 321 | return amdtp_stream_add_pcm_hw_constraints(s, runtime); |
| 322 | } |
| 323 | |
| 324 | void amdtp_dot_midi_trigger(struct amdtp_stream *s, unsigned int port, |
| 325 | struct snd_rawmidi_substream *midi) |
| 326 | { |
| 327 | struct amdtp_dot *p = s->protocol; |
| 328 | |
| 329 | if (port < MAX_MIDI_PORTS) |
| 330 | ACCESS_ONCE(p->midi[port]) = midi; |
| 331 | } |
| 332 | |
| 333 | static unsigned int process_tx_data_blocks(struct amdtp_stream *s, |
| 334 | __be32 *buffer, |
| 335 | unsigned int data_blocks, |
| 336 | unsigned int *syt) |
| 337 | { |
| 338 | struct snd_pcm_substream *pcm; |
| 339 | unsigned int pcm_frames; |
| 340 | |
| 341 | pcm = ACCESS_ONCE(s->pcm); |
| 342 | if (pcm) { |
| 343 | read_pcm_s32(s, pcm, buffer, data_blocks); |
| 344 | pcm_frames = data_blocks; |
| 345 | } else { |
| 346 | pcm_frames = 0; |
| 347 | } |
| 348 | |
| 349 | read_midi_messages(s, buffer, data_blocks); |
| 350 | |
| 351 | return pcm_frames; |
| 352 | } |
| 353 | |
| 354 | static unsigned int process_rx_data_blocks(struct amdtp_stream *s, |
| 355 | __be32 *buffer, |
| 356 | unsigned int data_blocks, |
| 357 | unsigned int *syt) |
| 358 | { |
| 359 | struct snd_pcm_substream *pcm; |
| 360 | unsigned int pcm_frames; |
| 361 | |
| 362 | pcm = ACCESS_ONCE(s->pcm); |
| 363 | if (pcm) { |
| 364 | write_pcm_s32(s, pcm, buffer, data_blocks); |
| 365 | pcm_frames = data_blocks; |
| 366 | } else { |
| 367 | write_pcm_silence(s, buffer, data_blocks); |
| 368 | pcm_frames = 0; |
| 369 | } |
| 370 | |
| 371 | write_midi_messages(s, buffer, data_blocks); |
| 372 | |
| 373 | return pcm_frames; |
| 374 | } |
| 375 | |
| 376 | int amdtp_dot_init(struct amdtp_stream *s, struct fw_unit *unit, |
| 377 | enum amdtp_stream_direction dir) |
| 378 | { |
| 379 | amdtp_stream_process_data_blocks_t process_data_blocks; |
| 380 | enum cip_flags flags; |
| 381 | |
| 382 | /* Use different mode between incoming/outgoing. */ |
| 383 | if (dir == AMDTP_IN_STREAM) { |
| 384 | flags = CIP_NONBLOCKING; |
| 385 | process_data_blocks = process_tx_data_blocks; |
| 386 | } else { |
| 387 | flags = CIP_BLOCKING; |
| 388 | process_data_blocks = process_rx_data_blocks; |
| 389 | } |
| 390 | |
| 391 | return amdtp_stream_init(s, unit, dir, flags, CIP_FMT_AM, |
| 392 | process_data_blocks, sizeof(struct amdtp_dot)); |
| 393 | } |
| 394 | |
| 395 | void amdtp_dot_reset(struct amdtp_stream *s) |
| 396 | { |
| 397 | struct amdtp_dot *p = s->protocol; |
| 398 | |
| 399 | p->state.carry = 0x00; |
| 400 | p->state.idx = 0x00; |
| 401 | p->state.off = 0; |
| 402 | } |