sound/firewire/digi00x/amdtp-dot.c

   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         void (*transfer_samples)(struct amdtp_stream *s,
  53                                  struct snd_pcm_substream *pcm,
  54                                  __be32 *buffer, unsigned int frames);
  55 };
  56
  57 /*
  58  * double-oh-three look up table
  59  *
  60  * @param idx index byte (audio-sample data) 0x00..0xff
  61  * @param off channel offset shift
  62  * @return salt to XOR with given data
  63  */
  64 #define BYTE_PER_SAMPLE (4)
  65 #define MAGIC_DOT_BYTE (2)
  66 #define MAGIC_BYTE_OFF(x) (((x) * BYTE_PER_SAMPLE) + MAGIC_DOT_BYTE)
  67 static u8 dot_scrt(const u8 idx, const unsigned int off)
  68 {
  69         /*
  70          * the length of the added pattern only depends on the lower nibble
  71          * of the last non-zero data
  72          */
  73         static const u8 len[16] = {0, 1, 3, 5, 7, 9, 11, 13, 14,
  74                                    12, 10, 8, 6, 4, 2, 0};
  75
  76         /*
  77          * the lower nibble of the salt. Interleaved sequence.
  78          * this is walked backwards according to len[]
  79          */
  80         static const u8 nib[15] = {0x8, 0x7, 0x9, 0x6, 0xa, 0x5, 0xb, 0x4,
  81                                    0xc, 0x3, 0xd, 0x2, 0xe, 0x1, 0xf};
  82
  83         /* circular list for the salt's hi nibble. */
  84         static const u8 hir[15] = {0x0, 0x6, 0xf, 0x8, 0x7, 0x5, 0x3, 0x4,
  85                                    0xc, 0xd, 0xe, 0x1, 0x2, 0xb, 0xa};
  86
  87         /*
  88          * start offset for upper nibble mapping.
  89          * note: 9 is /special/. In the case where the high nibble == 0x9,
  90          * hir[] is not used and - coincidentally - the salt's hi nibble is
  91          * 0x09 regardless of the offset.
  92          */
  93         static const u8 hio[16] = {0, 11, 12, 6, 7, 5, 1, 4,
  94                                    3, 0x00, 14, 13, 8, 9, 10, 2};
  95
  96         const u8 ln = idx & 0xf;
  97         const u8 hn = (idx >> 4) & 0xf;
  98         const u8 hr = (hn == 0x9) ? 0x9 : hir[(hio[hn] + off) % 15];
  99
 100         if (len[ln] < off)
 101                 return 0x00;
 102
 103         return ((nib[14 + off - len[ln]]) | (hr << 4));
 104 }
 105
 106 static void dot_encode_step(struct dot_state *state, __be32 *const buffer)
 107 {
 108         u8 * const data = (u8 *) buffer;
 109
 110         if (data[MAGIC_DOT_BYTE] != 0x00) {
 111                 state->off = 0;
 112                 state->idx = data[MAGIC_DOT_BYTE] ^ state->carry;
 113         }
 114         data[MAGIC_DOT_BYTE] ^= state->carry;
 115         state->carry = dot_scrt(state->idx, ++(state->off));
 116 }
 117
 118 int amdtp_dot_set_parameters(struct amdtp_stream *s, unsigned int rate,
 119                              unsigned int pcm_channels)
 120 {
 121         struct amdtp_dot *p = s->protocol;
 122         int err;
 123
 124         if (amdtp_stream_running(s))
 125                 return -EBUSY;
 126
 127         /*
 128          * A first data channel is for MIDI messages, the rest is Multi Bit
 129          * Linear Audio data channel.
 130          */
 131         err = amdtp_stream_set_parameters(s, rate, pcm_channels + 1);
 132         if (err < 0)
 133                 return err;
 134
 135         s->fdf = AMDTP_FDF_AM824 | s->sfc;
 136
 137         p->pcm_channels = pcm_channels;
 138
 139         /*
 140          * We do not know the actual MIDI FIFO size of most devices.  Just
 141          * assume two bytes, i.e., one byte can be received over the bus while
 142          * the previous one is transmitted over MIDI.
 143          * (The value here is adjusted for midi_ratelimit_per_packet().)
 144          */
 145         p->midi_fifo_limit = rate - MIDI_BYTES_PER_SECOND * s->syt_interval + 1;
 146
 147         return 0;
 148 }
 149
 150 static void write_pcm_s32(struct amdtp_stream *s, struct snd_pcm_substream *pcm,
 151                           __be32 *buffer, unsigned int frames)
 152 {
 153         struct amdtp_dot *p = s->protocol;
 154         struct snd_pcm_runtime *runtime = pcm->runtime;
 155         unsigned int channels, remaining_frames, i, c;
 156         const u32 *src;
 157
 158         channels = p->pcm_channels;
 159         src = (void *)runtime->dma_area +
 160                         frames_to_bytes(runtime, s->pcm_buffer_pointer);
 161         remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer;
 162
 163         buffer++;
 164         for (i = 0; i < frames; ++i) {
 165                 for (c = 0; c < channels; ++c) {
 166                         buffer[c] = cpu_to_be32((*src >> 8) | 0x40000000);
 167                         dot_encode_step(&p->state, &buffer[c]);
 168                         src++;
 169                 }
 170                 buffer += s->data_block_quadlets;
 171                 if (--remaining_frames == 0)
 172                         src = (void *)runtime->dma_area;
 173         }
 174 }
 175
 176 static void write_pcm_s16(struct amdtp_stream *s, struct snd_pcm_substream *pcm,
 177                           __be32 *buffer, unsigned int frames)
 178 {
 179         struct amdtp_dot *p = s->protocol;
 180         struct snd_pcm_runtime *runtime = pcm->runtime;
 181         unsigned int channels, remaining_frames, i, c;
 182         const u16 *src;
 183
 184         channels = p->pcm_channels;
 185         src = (void *)runtime->dma_area +
 186                         frames_to_bytes(runtime, s->pcm_buffer_pointer);
 187         remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer;
 188
 189         buffer++;
 190         for (i = 0; i < frames; ++i) {
 191                 for (c = 0; c < channels; ++c) {
 192                         buffer[c] = cpu_to_be32((*src << 8) | 0x40000000);
 193                         dot_encode_step(&p->state, &buffer[c]);
 194                         src++;
 195                 }
 196                 buffer += s->data_block_quadlets;
 197                 if (--remaining_frames == 0)
 198                         src = (void *)runtime->dma_area;
 199         }
 200 }
 201
 202 static void read_pcm_s32(struct amdtp_stream *s, struct snd_pcm_substream *pcm,
 203                          __be32 *buffer, unsigned int frames)
 204 {
 205         struct amdtp_dot *p = s->protocol;
 206         struct snd_pcm_runtime *runtime = pcm->runtime;
 207         unsigned int channels, remaining_frames, i, c;
 208         u32 *dst;
 209
 210         channels = p->pcm_channels;
 211         dst  = (void *)runtime->dma_area +
 212                         frames_to_bytes(runtime, s->pcm_buffer_pointer);
 213         remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer;
 214
 215         buffer++;
 216         for (i = 0; i < frames; ++i) {
 217                 for (c = 0; c < channels; ++c) {
 218                         *dst = be32_to_cpu(buffer[c]) << 8;
 219                         dst++;
 220                 }
 221                 buffer += s->data_block_quadlets;
 222                 if (--remaining_frames == 0)
 223                         dst = (void *)runtime->dma_area;
 224         }
 225 }
 226
 227 static void write_pcm_silence(struct amdtp_stream *s, __be32 *buffer,
 228                               unsigned int data_blocks)
 229 {
 230         struct amdtp_dot *p = s->protocol;
 231         unsigned int channels, i, c;
 232
 233         channels = p->pcm_channels;
 234
 235         buffer++;
 236         for (i = 0; i < data_blocks; ++i) {
 237                 for (c = 0; c < channels; ++c)
 238                         buffer[c] = cpu_to_be32(0x40000000);
 239                 buffer += s->data_block_quadlets;
 240         }
 241 }
 242
 243 static bool midi_ratelimit_per_packet(struct amdtp_stream *s, unsigned int port)
 244 {
 245         struct amdtp_dot *p = s->protocol;
 246         int used;
 247
 248         used = p->midi_fifo_used[port];
 249         if (used == 0)
 250                 return true;
 251
 252         used -= MIDI_BYTES_PER_SECOND * s->syt_interval;
 253         used = max(used, 0);
 254         p->midi_fifo_used[port] = used;
 255
 256         return used < p->midi_fifo_limit;
 257 }
 258
 259 static inline void midi_use_bytes(struct amdtp_stream *s,
 260                                   unsigned int port, unsigned int count)
 261 {
 262         struct amdtp_dot *p = s->protocol;
 263
 264         p->midi_fifo_used[port] += amdtp_rate_table[s->sfc] * count;
 265 }
 266
 267 static void write_midi_messages(struct amdtp_stream *s, __be32 *buffer,
 268                                 unsigned int data_blocks)
 269 {
 270         struct amdtp_dot *p = s->protocol;
 271         unsigned int f, port;
 272         int len;
 273         u8 *b;
 274
 275         for (f = 0; f < data_blocks; f++) {
 276                 port = (s->data_block_counter + f) % 8;
 277                 b = (u8 *)&buffer[0];
 278
 279                 len = 0;
 280                 if (port < MAX_MIDI_PORTS &&
 281                     midi_ratelimit_per_packet(s, port) &&
 282                     p->midi[port] != NULL)
 283                         len = snd_rawmidi_transmit(p->midi[port], b + 1, 2);
 284
 285                 if (len > 0) {
 286                         /*
 287                          * Upper 4 bits of LSB represent port number.
 288                          * - 0000b: physical MIDI port 1.
 289                          * - 0010b: physical MIDI port 2.
 290                          * - 1110b: console MIDI port.
 291                          */
 292                         if (port == 2)
 293                                 b[3] = 0xe0;
 294                         else if (port == 1)
 295                                 b[3] = 0x20;
 296                         else
 297                                 b[3] = 0x00;
 298                         b[3] |= len;
 299                         midi_use_bytes(s, port, len);
 300                 } else {
 301                         b[1] = 0;
 302                         b[2] = 0;
 303                         b[3] = 0;
 304                 }
 305                 b[0] = 0x80;
 306
 307                 buffer += s->data_block_quadlets;
 308         }
 309 }
 310
 311 static void read_midi_messages(struct amdtp_stream *s, __be32 *buffer,
 312                                unsigned int data_blocks)
 313 {
 314         struct amdtp_dot *p = s->protocol;
 315         unsigned int f, port, len;
 316         u8 *b;
 317
 318         for (f = 0; f < data_blocks; f++) {
 319                 b = (u8 *)&buffer[0];
 320
 321                 len = b[3] & 0x0f;
 322                 if (len > 0) {
 323                         /*
 324                          * Upper 4 bits of LSB represent port number.
 325                          * - 0000b: physical MIDI port 1. Use port 0.
 326                          * - 1110b: console MIDI port. Use port 2.
 327                          */
 328                         if (b[3] >> 4 > 0)
 329                                 port = 2;
 330                         else
 331                                 port = 0;
 332
 333                         if (port < MAX_MIDI_PORTS && p->midi[port])
 334                                 snd_rawmidi_receive(p->midi[port], b + 1, len);
 335                 }
 336
 337                 buffer += s->data_block_quadlets;
 338         }
 339 }
 340
 341 int amdtp_dot_add_pcm_hw_constraints(struct amdtp_stream *s,
 342                                      struct snd_pcm_runtime *runtime)
 343 {
 344         int err;
 345
 346         /* This protocol delivers 24 bit data in 32bit data channel. */
 347         err = snd_pcm_hw_constraint_msbits(runtime, 0, 32, 24);
 348         if (err < 0)
 349                 return err;
 350
 351         return amdtp_stream_add_pcm_hw_constraints(s, runtime);
 352 }
 353
 354 void amdtp_dot_set_pcm_format(struct amdtp_stream *s, snd_pcm_format_t format)
 355 {
 356         struct amdtp_dot *p = s->protocol;
 357
 358         if (WARN_ON(amdtp_stream_pcm_running(s)))
 359                 return;
 360
 361         switch (format) {
 362         default:
 363                 WARN_ON(1);
 364                 /* fall through */
 365         case SNDRV_PCM_FORMAT_S16:
 366                 if (s->direction == AMDTP_OUT_STREAM) {
 367                         p->transfer_samples = write_pcm_s16;
 368                         break;
 369                 }
 370                 WARN_ON(1);
 371                 /* fall through */
 372         case SNDRV_PCM_FORMAT_S32:
 373                 if (s->direction == AMDTP_OUT_STREAM)
 374                         p->transfer_samples = write_pcm_s32;
 375                 else
 376                         p->transfer_samples = read_pcm_s32;
 377                 break;
 378         }
 379 }
 380
 381 void amdtp_dot_midi_trigger(struct amdtp_stream *s, unsigned int port,
 382                           struct snd_rawmidi_substream *midi)
 383 {
 384         struct amdtp_dot *p = s->protocol;
 385
 386         if (port < MAX_MIDI_PORTS)
 387                 ACCESS_ONCE(p->midi[port]) = midi;
 388 }
 389
 390 static unsigned int process_tx_data_blocks(struct amdtp_stream *s,
 391                                            __be32 *buffer,
 392                                            unsigned int data_blocks,
 393                                            unsigned int *syt)
 394 {
 395         struct amdtp_dot *p = (struct amdtp_dot *)s->protocol;
 396         struct snd_pcm_substream *pcm;
 397         unsigned int pcm_frames;
 398
 399         pcm = ACCESS_ONCE(s->pcm);
 400         if (pcm) {
 401                 p->transfer_samples(s, pcm, buffer, data_blocks);
 402                 pcm_frames = data_blocks;
 403         } else {
 404                 pcm_frames = 0;
 405         }
 406
 407         read_midi_messages(s, buffer, data_blocks);
 408
 409         return pcm_frames;
 410 }
 411
 412 static unsigned int process_rx_data_blocks(struct amdtp_stream *s,
 413                                            __be32 *buffer,
 414                                            unsigned int data_blocks,
 415                                            unsigned int *syt)
 416 {
 417         struct amdtp_dot *p = (struct amdtp_dot *)s->protocol;
 418         struct snd_pcm_substream *pcm;
 419         unsigned int pcm_frames;
 420
 421         pcm = ACCESS_ONCE(s->pcm);
 422         if (pcm) {
 423                 p->transfer_samples(s, pcm, buffer, data_blocks);
 424                 pcm_frames = data_blocks;
 425         } else {
 426                 write_pcm_silence(s, buffer, data_blocks);
 427                 pcm_frames = 0;
 428         }
 429
 430         write_midi_messages(s, buffer, data_blocks);
 431
 432         return pcm_frames;
 433 }
 434
 435 int amdtp_dot_init(struct amdtp_stream *s, struct fw_unit *unit,
 436                  enum amdtp_stream_direction dir)
 437 {
 438         amdtp_stream_process_data_blocks_t process_data_blocks;
 439         enum cip_flags flags;
 440
 441         /* Use different mode between incoming/outgoing. */
 442         if (dir == AMDTP_IN_STREAM) {
 443                 flags = CIP_NONBLOCKING;
 444                 process_data_blocks = process_tx_data_blocks;
 445         } else {
 446                 flags = CIP_BLOCKING;
 447                 process_data_blocks = process_rx_data_blocks;
 448         }
 449
 450         return amdtp_stream_init(s, unit, dir, flags, CIP_FMT_AM,
 451                                  process_data_blocks, sizeof(struct amdtp_dot));
 452 }
 453
 454 void amdtp_dot_reset(struct amdtp_stream *s)
 455 {
 456         struct amdtp_dot *p = s->protocol;
 457
 458         p->state.carry = 0x00;
 459         p->state.idx = 0x00;
 460         p->state.off = 0;
 461 }