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 /*
  32  * The double-oh-three algorithm was discovered by Robin Gareus and Damien
  33  * Zammit in 2012, with reverse-engineering for Digi 003 Rack.
  34  */
  35 struct dot_state {
  36         u8 carry;
  37         u8 idx;
  38         unsigned int off;
  39 };
  40
  41 struct amdtp_dot {
  42         unsigned int pcm_channels;
  43         struct dot_state state;
  44
  45         unsigned int midi_ports;
  46         /* 2 = MAX(DOT_MIDI_IN_PORTS, DOT_MIDI_OUT_PORTS) */
  47         struct snd_rawmidi_substream *midi[2];
  48         int midi_fifo_used[2];
  49         int midi_fifo_limit;
  50
  51         void (*transfer_samples)(struct amdtp_stream *s,
  52                                  struct snd_pcm_substream *pcm,
  53                                  __be32 *buffer, unsigned int frames);
  54 };
  55
  56 /*
  57  * double-oh-three look up table
  58  *
  59  * @param idx index byte (audio-sample data) 0x00..0xff
  60  * @param off channel offset shift
  61  * @return salt to XOR with given data
  62  */
  63 #define BYTE_PER_SAMPLE (4)
  64 #define MAGIC_DOT_BYTE (2)
  65 #define MAGIC_BYTE_OFF(x) (((x) * BYTE_PER_SAMPLE) + MAGIC_DOT_BYTE)
  66 static u8 dot_scrt(const u8 idx, const unsigned int off)
  67 {
  68         /*
  69          * the length of the added pattern only depends on the lower nibble
  70          * of the last non-zero data
  71          */
  72         static const u8 len[16] = {0, 1, 3, 5, 7, 9, 11, 13, 14,
  73                                    12, 10, 8, 6, 4, 2, 0};
  74
  75         /*
  76          * the lower nibble of the salt. Interleaved sequence.
  77          * this is walked backwards according to len[]
  78          */
  79         static const u8 nib[15] = {0x8, 0x7, 0x9, 0x6, 0xa, 0x5, 0xb, 0x4,
  80                                    0xc, 0x3, 0xd, 0x2, 0xe, 0x1, 0xf};
  81
  82         /* circular list for the salt's hi nibble. */
  83         static const u8 hir[15] = {0x0, 0x6, 0xf, 0x8, 0x7, 0x5, 0x3, 0x4,
  84                                    0xc, 0xd, 0xe, 0x1, 0x2, 0xb, 0xa};
  85
  86         /*
  87          * start offset for upper nibble mapping.
  88          * note: 9 is /special/. In the case where the high nibble == 0x9,
  89          * hir[] is not used and - coincidentally - the salt's hi nibble is
  90          * 0x09 regardless of the offset.
  91          */
  92         static const u8 hio[16] = {0, 11, 12, 6, 7, 5, 1, 4,
  93                                    3, 0x00, 14, 13, 8, 9, 10, 2};
  94
  95         const u8 ln = idx & 0xf;
  96         const u8 hn = (idx >> 4) & 0xf;
  97         const u8 hr = (hn == 0x9) ? 0x9 : hir[(hio[hn] + off) % 15];
  98
  99         if (len[ln] < off)
 100                 return 0x00;
 101
 102         return ((nib[14 + off - len[ln]]) | (hr << 4));
 103 }
 104
 105 static void dot_encode_step(struct dot_state *state, __be32 *const buffer)
 106 {
 107         u8 * const data = (u8 *) buffer;
 108
 109         if (data[MAGIC_DOT_BYTE] != 0x00) {
 110                 state->off = 0;
 111                 state->idx = data[MAGIC_DOT_BYTE] ^ state->carry;
 112         }
 113         data[MAGIC_DOT_BYTE] ^= state->carry;
 114         state->carry = dot_scrt(state->idx, ++(state->off));
 115 }
 116
 117 int amdtp_dot_set_parameters(struct amdtp_stream *s, unsigned int rate,
 118                              unsigned int pcm_channels)
 119 {
 120         struct amdtp_dot *p = s->protocol;
 121         int err;
 122
 123         if (amdtp_stream_running(s))
 124                 return -EBUSY;
 125
 126         /*
 127          * A first data channel is for MIDI conformant data channel, the rest is
 128          * Multi Bit Linear Audio data channel.
 129          */
 130         err = amdtp_stream_set_parameters(s, rate, pcm_channels + 1);
 131         if (err < 0)
 132                 return err;
 133
 134         s->fdf = AMDTP_FDF_AM824 | s->sfc;
 135
 136         p->pcm_channels = pcm_channels;
 137
 138         if (s->direction == AMDTP_IN_STREAM)
 139                 p->midi_ports = DOT_MIDI_IN_PORTS;
 140         else
 141                 p->midi_ports = DOT_MIDI_OUT_PORTS;
 142
 143         /*
 144          * We do not know the actual MIDI FIFO size of most devices.  Just
 145          * assume two bytes, i.e., one byte can be received over the bus while
 146          * the previous one is transmitted over MIDI.
 147          * (The value here is adjusted for midi_ratelimit_per_packet().)
 148          */
 149         p->midi_fifo_limit = rate - MIDI_BYTES_PER_SECOND * s->syt_interval + 1;
 150
 151         return 0;
 152 }
 153
 154 static void write_pcm_s32(struct amdtp_stream *s, struct snd_pcm_substream *pcm,
 155                           __be32 *buffer, unsigned int frames)
 156 {
 157         struct amdtp_dot *p = s->protocol;
 158         struct snd_pcm_runtime *runtime = pcm->runtime;
 159         unsigned int channels, remaining_frames, i, c;
 160         const u32 *src;
 161
 162         channels = p->pcm_channels;
 163         src = (void *)runtime->dma_area +
 164                         frames_to_bytes(runtime, s->pcm_buffer_pointer);
 165         remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer;
 166
 167         buffer++;
 168         for (i = 0; i < frames; ++i) {
 169                 for (c = 0; c < channels; ++c) {
 170                         buffer[c] = cpu_to_be32((*src >> 8) | 0x40000000);
 171                         dot_encode_step(&p->state, &buffer[c]);
 172                         src++;
 173                 }
 174                 buffer += s->data_block_quadlets;
 175                 if (--remaining_frames == 0)
 176                         src = (void *)runtime->dma_area;
 177         }
 178 }
 179
 180 static void write_pcm_s16(struct amdtp_stream *s, struct snd_pcm_substream *pcm,
 181                           __be32 *buffer, unsigned int frames)
 182 {
 183         struct amdtp_dot *p = s->protocol;
 184         struct snd_pcm_runtime *runtime = pcm->runtime;
 185         unsigned int channels, remaining_frames, i, c;
 186         const u16 *src;
 187
 188         channels = p->pcm_channels;
 189         src = (void *)runtime->dma_area +
 190                         frames_to_bytes(runtime, s->pcm_buffer_pointer);
 191         remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer;
 192
 193         buffer++;
 194         for (i = 0; i < frames; ++i) {
 195                 for (c = 0; c < channels; ++c) {
 196                         buffer[c] = cpu_to_be32((*src << 8) | 0x40000000);
 197                         dot_encode_step(&p->state, &buffer[c]);
 198                         src++;
 199                 }
 200                 buffer += s->data_block_quadlets;
 201                 if (--remaining_frames == 0)
 202                         src = (void *)runtime->dma_area;
 203         }
 204 }
 205
 206 static void read_pcm_s32(struct amdtp_stream *s, struct snd_pcm_substream *pcm,
 207                          __be32 *buffer, unsigned int frames)
 208 {
 209         struct amdtp_dot *p = s->protocol;
 210         struct snd_pcm_runtime *runtime = pcm->runtime;
 211         unsigned int channels, remaining_frames, i, c;
 212         u32 *dst;
 213
 214         channels = p->pcm_channels;
 215         dst  = (void *)runtime->dma_area +
 216                         frames_to_bytes(runtime, s->pcm_buffer_pointer);
 217         remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer;
 218
 219         buffer++;
 220         for (i = 0; i < frames; ++i) {
 221                 for (c = 0; c < channels; ++c) {
 222                         *dst = be32_to_cpu(buffer[c]) << 8;
 223                         dst++;
 224                 }
 225                 buffer += s->data_block_quadlets;
 226                 if (--remaining_frames == 0)
 227                         dst = (void *)runtime->dma_area;
 228         }
 229 }
 230
 231 static void write_pcm_silence(struct amdtp_stream *s, __be32 *buffer,
 232                               unsigned int data_blocks)
 233 {
 234         struct amdtp_dot *p = s->protocol;
 235         unsigned int channels, i, c;
 236
 237         channels = p->pcm_channels;
 238
 239         buffer++;
 240         for (i = 0; i < data_blocks; ++i) {
 241                 for (c = 0; c < channels; ++c)
 242                         buffer[c] = cpu_to_be32(0x40000000);
 243                 buffer += s->data_block_quadlets;
 244         }
 245 }
 246
 247 static bool midi_ratelimit_per_packet(struct amdtp_stream *s, unsigned int port)
 248 {
 249         struct amdtp_dot *p = s->protocol;
 250         int used;
 251
 252         used = p->midi_fifo_used[port];
 253         if (used == 0)
 254                 return true;
 255
 256         used -= MIDI_BYTES_PER_SECOND * s->syt_interval;
 257         used = max(used, 0);
 258         p->midi_fifo_used[port] = used;
 259
 260         return used < p->midi_fifo_limit;
 261 }
 262
 263 static inline void midi_use_bytes(struct amdtp_stream *s,
 264                                   unsigned int port, unsigned int count)
 265 {
 266         struct amdtp_dot *p = s->protocol;
 267
 268         p->midi_fifo_used[port] += amdtp_rate_table[s->sfc] * count;
 269 }
 270
 271 static void write_midi_messages(struct amdtp_stream *s, __be32 *buffer,
 272                                 unsigned int data_blocks)
 273 {
 274         struct amdtp_dot *p = s->protocol;
 275         unsigned int f, port;
 276         int len;
 277         u8 *b;
 278
 279         for (f = 0; f < data_blocks; f++) {
 280                 port = (s->data_block_counter + f) % 8;
 281                 b = (u8 *)&buffer[0];
 282
 283                 len = 0;
 284                 if (port < p->midi_ports &&
 285                     midi_ratelimit_per_packet(s, port) &&
 286                     p->midi[port] != NULL)
 287                         len = snd_rawmidi_transmit(p->midi[port], b + 1, 2);
 288
 289                 if (len > 0) {
 290                         b[3] = (0x10 << port) | len;
 291                         midi_use_bytes(s, port, len);
 292                 } else {
 293                         b[1] = 0;
 294                         b[2] = 0;
 295                         b[3] = 0;
 296                 }
 297                 b[0] = 0x80;
 298
 299                 buffer += s->data_block_quadlets;
 300         }
 301 }
 302
 303 static void read_midi_messages(struct amdtp_stream *s, __be32 *buffer,
 304                                unsigned int data_blocks)
 305 {
 306         struct amdtp_dot *p = s->protocol;
 307         unsigned int f, port, len;
 308         u8 *b;
 309
 310         for (f = 0; f < data_blocks; f++) {
 311                 b = (u8 *)&buffer[0];
 312                 port = b[3] >> 4;
 313                 len = b[3] & 0x0f;
 314
 315                 if (port < p->midi_ports && p->midi[port] && len > 0)
 316                         snd_rawmidi_receive(p->midi[port], b + 1, len);
 317
 318                 buffer += s->data_block_quadlets;
 319         }
 320 }
 321
 322 int amdtp_dot_add_pcm_hw_constraints(struct amdtp_stream *s,
 323                                      struct snd_pcm_runtime *runtime)
 324 {
 325         int err;
 326
 327         /* This protocol delivers 24 bit data in 32bit data channel. */
 328         err = snd_pcm_hw_constraint_msbits(runtime, 0, 32, 24);
 329         if (err < 0)
 330                 return err;
 331
 332         return amdtp_stream_add_pcm_hw_constraints(s, runtime);
 333 }
 334
 335 void amdtp_dot_set_pcm_format(struct amdtp_stream *s, snd_pcm_format_t format)
 336 {
 337         struct amdtp_dot *p = s->protocol;
 338
 339         if (WARN_ON(amdtp_stream_pcm_running(s)))
 340                 return;
 341
 342         switch (format) {
 343         default:
 344                 WARN_ON(1);
 345                 /* fall through */
 346         case SNDRV_PCM_FORMAT_S16:
 347                 if (s->direction == AMDTP_OUT_STREAM) {
 348                         p->transfer_samples = write_pcm_s16;
 349                         break;
 350                 }
 351                 WARN_ON(1);
 352                 /* fall through */
 353         case SNDRV_PCM_FORMAT_S32:
 354                 if (s->direction == AMDTP_OUT_STREAM)
 355                         p->transfer_samples = write_pcm_s32;
 356                 else
 357                         p->transfer_samples = read_pcm_s32;
 358                 break;
 359         }
 360 }
 361
 362 void amdtp_dot_midi_trigger(struct amdtp_stream *s, unsigned int port,
 363                           struct snd_rawmidi_substream *midi)
 364 {
 365         struct amdtp_dot *p = s->protocol;
 366
 367         if (port < p->midi_ports)
 368                 ACCESS_ONCE(p->midi[port]) = midi;
 369 }
 370
 371 static unsigned int process_tx_data_blocks(struct amdtp_stream *s,
 372                                            __be32 *buffer,
 373                                            unsigned int data_blocks,
 374                                            unsigned int *syt)
 375 {
 376         struct amdtp_dot *p = (struct amdtp_dot *)s->protocol;
 377         struct snd_pcm_substream *pcm;
 378         unsigned int pcm_frames;
 379
 380         pcm = ACCESS_ONCE(s->pcm);
 381         if (pcm) {
 382                 p->transfer_samples(s, pcm, buffer, data_blocks);
 383                 pcm_frames = data_blocks;
 384         } else {
 385                 pcm_frames = 0;
 386         }
 387
 388         read_midi_messages(s, buffer, data_blocks);
 389
 390         return pcm_frames;
 391 }
 392
 393 static unsigned int process_rx_data_blocks(struct amdtp_stream *s,
 394                                            __be32 *buffer,
 395                                            unsigned int data_blocks,
 396                                            unsigned int *syt)
 397 {
 398         struct amdtp_dot *p = (struct amdtp_dot *)s->protocol;
 399         struct snd_pcm_substream *pcm;
 400         unsigned int pcm_frames;
 401
 402         pcm = ACCESS_ONCE(s->pcm);
 403         if (pcm) {
 404                 p->transfer_samples(s, pcm, buffer, data_blocks);
 405                 pcm_frames = data_blocks;
 406         } else {
 407                 write_pcm_silence(s, buffer, data_blocks);
 408                 pcm_frames = 0;
 409         }
 410
 411         write_midi_messages(s, buffer, data_blocks);
 412
 413         return pcm_frames;
 414 }
 415
 416 int amdtp_dot_init(struct amdtp_stream *s, struct fw_unit *unit,
 417                  enum amdtp_stream_direction dir)
 418 {
 419         amdtp_stream_process_data_blocks_t process_data_blocks;
 420         enum cip_flags flags;
 421
 422         /* Use different mode between incoming/outgoing. */
 423         if (dir == AMDTP_IN_STREAM) {
 424                 flags = CIP_NONBLOCKING;
 425                 process_data_blocks = process_tx_data_blocks;
 426         } else {
 427                 flags = CIP_BLOCKING;
 428                 process_data_blocks = process_rx_data_blocks;
 429         }
 430
 431         return amdtp_stream_init(s, unit, dir, flags, CIP_FMT_AM,
 432                                  process_data_blocks, sizeof(struct amdtp_dot));
 433 }
 434
 435 void amdtp_dot_reset(struct amdtp_stream *s)
 436 {
 437         struct amdtp_dot *p = s->protocol;
 438
 439         p->state.carry = 0x00;
 440         p->state.idx = 0x00;
 441         p->state.off = 0;
 442 }