sound/firewire/amdtp.c

   1 /*
   2  * Audio and Music Data Transmission Protocol (IEC 61883-6) streams
   3  * with Common Isochronous Packet (IEC 61883-1) headers
   4  *
   5  * Copyright (c) Clemens Ladisch <clemens@ladisch.de>
   6  * Licensed under the terms of the GNU General Public License, version 2.
   7  */
   8
   9 #include <linux/device.h>
  10 #include <linux/err.h>
  11 #include <linux/firewire.h>
  12 #include <linux/module.h>
  13 #include <linux/slab.h>
  14 #include <sound/pcm.h>
  15 #include "amdtp.h"
  16
  17 #define TICKS_PER_CYCLE         3072
  18 #define CYCLES_PER_SECOND       8000
  19 #define TICKS_PER_SECOND        (TICKS_PER_CYCLE * CYCLES_PER_SECOND)
  20
  21 #define TRANSFER_DELAY_TICKS    0x2e00 /* 479.17 µs */
  22
  23 #define TAG_CIP                 1
  24
  25 #define CIP_EOH                 (1u << 31)
  26 #define CIP_FMT_AM              (0x10 << 24)
  27 #define AMDTP_FDF_AM824         (0 << 19)
  28 #define AMDTP_FDF_SFC_SHIFT     16
  29
  30 /* TODO: make these configurable */
  31 #define INTERRUPT_INTERVAL      16
  32 #define QUEUE_LENGTH            48
  33
  34 /**
  35  * amdtp_out_stream_init - initialize an AMDTP output stream structure
  36  * @s: the AMDTP output stream to initialize
  37  * @unit: the target of the stream
  38  * @flags: the packet transmission method to use
  39  */
  40 int amdtp_out_stream_init(struct amdtp_out_stream *s, struct fw_unit *unit,
  41                           enum cip_out_flags flags)
  42 {
  43         s->unit = fw_unit_get(unit);
  44         s->flags = flags;
  45         s->context = ERR_PTR(-1);
  46         mutex_init(&s->mutex);
  47         s->packet_index = 0;
  48
  49         return 0;
  50 }
  51 EXPORT_SYMBOL(amdtp_out_stream_init);
  52
  53 /**
  54  * amdtp_out_stream_destroy - free stream resources
  55  * @s: the AMDTP output stream to destroy
  56  */
  57 void amdtp_out_stream_destroy(struct amdtp_out_stream *s)
  58 {
  59         WARN_ON(!IS_ERR(s->context));
  60         mutex_destroy(&s->mutex);
  61         fw_unit_put(s->unit);
  62 }
  63 EXPORT_SYMBOL(amdtp_out_stream_destroy);
  64
  65 /**
  66  * amdtp_out_stream_set_rate - set the sample rate
  67  * @s: the AMDTP output stream to configure
  68  * @rate: the sample rate
  69  *
  70  * The sample rate must be set before the stream is started, and must not be
  71  * changed while the stream is running.
  72  */
  73 void amdtp_out_stream_set_rate(struct amdtp_out_stream *s, unsigned int rate)
  74 {
  75         static const struct {
  76                 unsigned int rate;
  77                 unsigned int syt_interval;
  78         } rate_info[] = {
  79                 [CIP_SFC_32000]  = {  32000,  8, },
  80                 [CIP_SFC_44100]  = {  44100,  8, },
  81                 [CIP_SFC_48000]  = {  48000,  8, },
  82                 [CIP_SFC_88200]  = {  88200, 16, },
  83                 [CIP_SFC_96000]  = {  96000, 16, },
  84                 [CIP_SFC_176400] = { 176400, 32, },
  85                 [CIP_SFC_192000] = { 192000, 32, },
  86         };
  87         unsigned int sfc;
  88
  89         if (WARN_ON(!IS_ERR(s->context)))
  90                 return;
  91
  92         for (sfc = 0; sfc < ARRAY_SIZE(rate_info); ++sfc)
  93                 if (rate_info[sfc].rate == rate)
  94                         goto sfc_found;
  95         WARN_ON(1);
  96         return;
  97
  98 sfc_found:
  99         s->sfc = sfc;
 100         s->syt_interval = rate_info[sfc].syt_interval;
 101
 102         /* default buffering in the device */
 103         s->transfer_delay = TRANSFER_DELAY_TICKS - TICKS_PER_CYCLE;
 104         if (s->flags & CIP_BLOCKING)
 105                 /* additional buffering needed to adjust for no-data packets */
 106                 s->transfer_delay += TICKS_PER_SECOND * s->syt_interval / rate;
 107 }
 108 EXPORT_SYMBOL(amdtp_out_stream_set_rate);
 109
 110 /**
 111  * amdtp_out_stream_get_max_payload - get the stream's packet size
 112  * @s: the AMDTP output stream
 113  *
 114  * This function must not be called before the stream has been configured
 115  * with amdtp_out_stream_set_rate(), amdtp_out_stream_set_pcm(), and
 116  * amdtp_out_stream_set_midi().
 117  */
 118 unsigned int amdtp_out_stream_get_max_payload(struct amdtp_out_stream *s)
 119 {
 120         s->data_block_quadlets = s->pcm_channels;
 121         s->data_block_quadlets += DIV_ROUND_UP(s->midi_ports, 8);
 122
 123         return 8 + s->syt_interval * s->data_block_quadlets * 4;
 124 }
 125 EXPORT_SYMBOL(amdtp_out_stream_get_max_payload);
 126
 127 static void amdtp_write_s16(struct amdtp_out_stream *s,
 128                             struct snd_pcm_substream *pcm,
 129                             __be32 *buffer, unsigned int frames);
 130 static void amdtp_write_s32(struct amdtp_out_stream *s,
 131                             struct snd_pcm_substream *pcm,
 132                             __be32 *buffer, unsigned int frames);
 133
 134 /**
 135  * amdtp_out_stream_set_pcm_format - set the PCM format
 136  * @s: the AMDTP output stream to configure
 137  * @format: the format of the ALSA PCM device
 138  *
 139  * The sample format must be set before the stream is started, and must not be
 140  * changed while the stream is running.
 141  */
 142 void amdtp_out_stream_set_pcm_format(struct amdtp_out_stream *s,
 143                                      snd_pcm_format_t format)
 144 {
 145         if (WARN_ON(!IS_ERR(s->context)))
 146                 return;
 147
 148         switch (format) {
 149         default:
 150                 WARN_ON(1);
 151                 /* fall through */
 152         case SNDRV_PCM_FORMAT_S16:
 153                 s->transfer_samples = amdtp_write_s16;
 154                 break;
 155         case SNDRV_PCM_FORMAT_S32:
 156                 s->transfer_samples = amdtp_write_s32;
 157                 break;
 158         }
 159 }
 160 EXPORT_SYMBOL(amdtp_out_stream_set_pcm_format);
 161
 162 static unsigned int calculate_data_blocks(struct amdtp_out_stream *s)
 163 {
 164         unsigned int phase, data_blocks;
 165
 166         if (!cip_sfc_is_base_44100(s->sfc)) {
 167                 /* Sample_rate / 8000 is an integer, and precomputed. */
 168                 data_blocks = s->data_block_state;
 169         } else {
 170                 phase = s->data_block_state;
 171
 172                 /*
 173                  * This calculates the number of data blocks per packet so that
 174                  * 1) the overall rate is correct and exactly synchronized to
 175                  *    the bus clock, and
 176                  * 2) packets with a rounded-up number of blocks occur as early
 177                  *    as possible in the sequence (to prevent underruns of the
 178                  *    device's buffer).
 179                  */
 180                 if (s->sfc == CIP_SFC_44100)
 181                         /* 6 6 5 6 5 6 5 ... */
 182                         data_blocks = 5 + ((phase & 1) ^
 183                                            (phase == 0 || phase >= 40));
 184                 else
 185                         /* 12 11 11 11 11 ... or 23 22 22 22 22 ... */
 186                         data_blocks = 11 * (s->sfc >> 1) + (phase == 0);
 187                 if (++phase >= (80 >> (s->sfc >> 1)))
 188                         phase = 0;
 189                 s->data_block_state = phase;
 190         }
 191
 192         return data_blocks;
 193 }
 194
 195 static unsigned int calculate_syt(struct amdtp_out_stream *s,
 196                                   unsigned int cycle)
 197 {
 198         unsigned int syt_offset, phase, index, syt;
 199
 200         if (s->last_syt_offset < TICKS_PER_CYCLE) {
 201                 if (!cip_sfc_is_base_44100(s->sfc))
 202                         syt_offset = s->last_syt_offset + s->syt_offset_state;
 203                 else {
 204                 /*
 205                  * The time, in ticks, of the n'th SYT_INTERVAL sample is:
 206                  *   n * SYT_INTERVAL * 24576000 / sample_rate
 207                  * Modulo TICKS_PER_CYCLE, the difference between successive
 208                  * elements is about 1386.23.  Rounding the results of this
 209                  * formula to the SYT precision results in a sequence of
 210                  * differences that begins with:
 211                  *   1386 1386 1387 1386 1386 1386 1387 1386 1386 1386 1387 ...
 212                  * This code generates _exactly_ the same sequence.
 213                  */
 214                         phase = s->syt_offset_state;
 215                         index = phase % 13;
 216                         syt_offset = s->last_syt_offset;
 217                         syt_offset += 1386 + ((index && !(index & 3)) ||
 218                                               phase == 146);
 219                         if (++phase >= 147)
 220                                 phase = 0;
 221                         s->syt_offset_state = phase;
 222                 }
 223         } else
 224                 syt_offset = s->last_syt_offset - TICKS_PER_CYCLE;
 225         s->last_syt_offset = syt_offset;
 226
 227         if (syt_offset < TICKS_PER_CYCLE) {
 228                 syt_offset += s->transfer_delay;
 229                 syt = (cycle + syt_offset / TICKS_PER_CYCLE) << 12;
 230                 syt += syt_offset % TICKS_PER_CYCLE;
 231
 232                 return syt & 0xffff;
 233         } else {
 234                 return 0xffff; /* no info */
 235         }
 236 }
 237
 238 static void amdtp_write_s32(struct amdtp_out_stream *s,
 239                             struct snd_pcm_substream *pcm,
 240                             __be32 *buffer, unsigned int frames)
 241 {
 242         struct snd_pcm_runtime *runtime = pcm->runtime;
 243         unsigned int channels, remaining_frames, frame_step, i, c;
 244         const u32 *src;
 245
 246         channels = s->pcm_channels;
 247         src = (void *)runtime->dma_area +
 248                         s->pcm_buffer_pointer * (runtime->frame_bits / 8);
 249         remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer;
 250         frame_step = s->data_block_quadlets - channels;
 251
 252         for (i = 0; i < frames; ++i) {
 253                 for (c = 0; c < channels; ++c) {
 254                         *buffer = cpu_to_be32((*src >> 8) | 0x40000000);
 255                         src++;
 256                         buffer++;
 257                 }
 258                 buffer += frame_step;
 259                 if (--remaining_frames == 0)
 260                         src = (void *)runtime->dma_area;
 261         }
 262 }
 263
 264 static void amdtp_write_s16(struct amdtp_out_stream *s,
 265                             struct snd_pcm_substream *pcm,
 266                             __be32 *buffer, unsigned int frames)
 267 {
 268         struct snd_pcm_runtime *runtime = pcm->runtime;
 269         unsigned int channels, remaining_frames, frame_step, i, c;
 270         const u16 *src;
 271
 272         channels = s->pcm_channels;
 273         src = (void *)runtime->dma_area +
 274                         s->pcm_buffer_pointer * (runtime->frame_bits / 8);
 275         remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer;
 276         frame_step = s->data_block_quadlets - channels;
 277
 278         for (i = 0; i < frames; ++i) {
 279                 for (c = 0; c < channels; ++c) {
 280                         *buffer = cpu_to_be32((*src << 8) | 0x40000000);
 281                         src++;
 282                         buffer++;
 283                 }
 284                 buffer += frame_step;
 285                 if (--remaining_frames == 0)
 286                         src = (void *)runtime->dma_area;
 287         }
 288 }
 289
 290 static void amdtp_fill_pcm_silence(struct amdtp_out_stream *s,
 291                                    __be32 *buffer, unsigned int frames)
 292 {
 293         unsigned int i, c;
 294
 295         for (i = 0; i < frames; ++i) {
 296                 for (c = 0; c < s->pcm_channels; ++c)
 297                         buffer[c] = cpu_to_be32(0x40000000);
 298                 buffer += s->data_block_quadlets;
 299         }
 300 }
 301
 302 static void amdtp_fill_midi(struct amdtp_out_stream *s,
 303                             __be32 *buffer, unsigned int frames)
 304 {
 305         unsigned int i;
 306
 307         for (i = 0; i < frames; ++i)
 308                 buffer[s->pcm_channels + i * s->data_block_quadlets] =
 309                                                 cpu_to_be32(0x80000000);
 310 }
 311
 312 static void queue_out_packet(struct amdtp_out_stream *s, unsigned int cycle)
 313 {
 314         __be32 *buffer;
 315         unsigned int index, data_blocks, syt, ptr;
 316         struct snd_pcm_substream *pcm;
 317         struct fw_iso_packet packet;
 318         int err;
 319
 320         if (s->packet_index < 0)
 321                 return;
 322         index = s->packet_index;
 323
 324         syt = calculate_syt(s, cycle);
 325         if (!(s->flags & CIP_BLOCKING)) {
 326                 data_blocks = calculate_data_blocks(s);
 327         } else {
 328                 if (syt != 0xffff) {
 329                         data_blocks = s->syt_interval;
 330                 } else {
 331                         data_blocks = 0;
 332                         syt = 0xffffff;
 333                 }
 334         }
 335
 336         buffer = s->buffer.packets[index].buffer;
 337         buffer[0] = cpu_to_be32(ACCESS_ONCE(s->source_node_id_field) |
 338                                 (s->data_block_quadlets << 16) |
 339                                 s->data_block_counter);
 340         buffer[1] = cpu_to_be32(CIP_EOH | CIP_FMT_AM | AMDTP_FDF_AM824 |
 341                                 (s->sfc << AMDTP_FDF_SFC_SHIFT) | syt);
 342         buffer += 2;
 343
 344         pcm = ACCESS_ONCE(s->pcm);
 345         if (pcm)
 346                 s->transfer_samples(s, pcm, buffer, data_blocks);
 347         else
 348                 amdtp_fill_pcm_silence(s, buffer, data_blocks);
 349         if (s->midi_ports)
 350                 amdtp_fill_midi(s, buffer, data_blocks);
 351
 352         s->data_block_counter = (s->data_block_counter + data_blocks) & 0xff;
 353
 354         packet.payload_length = 8 + data_blocks * 4 * s->data_block_quadlets;
 355         packet.interrupt = IS_ALIGNED(index + 1, INTERRUPT_INTERVAL);
 356         packet.skip = 0;
 357         packet.tag = TAG_CIP;
 358         packet.sy = 0;
 359         packet.header_length = 0;
 360
 361         err = fw_iso_context_queue(s->context, &packet, &s->buffer.iso_buffer,
 362                                    s->buffer.packets[index].offset);
 363         if (err < 0) {
 364                 dev_err(&s->unit->device, "queueing error: %d\n", err);
 365                 s->packet_index = -1;
 366                 amdtp_out_stream_pcm_abort(s);
 367                 return;
 368         }
 369
 370         if (++index >= QUEUE_LENGTH)
 371                 index = 0;
 372         s->packet_index = index;
 373
 374         if (pcm) {
 375                 ptr = s->pcm_buffer_pointer + data_blocks;
 376                 if (ptr >= pcm->runtime->buffer_size)
 377                         ptr -= pcm->runtime->buffer_size;
 378                 ACCESS_ONCE(s->pcm_buffer_pointer) = ptr;
 379
 380                 s->pcm_period_pointer += data_blocks;
 381                 if (s->pcm_period_pointer >= pcm->runtime->period_size) {
 382                         s->pcm_period_pointer -= pcm->runtime->period_size;
 383                         snd_pcm_period_elapsed(pcm);
 384                 }
 385         }
 386 }
 387
 388 static void out_packet_callback(struct fw_iso_context *context, u32 cycle,
 389                                 size_t header_length, void *header, void *data)
 390 {
 391         struct amdtp_out_stream *s = data;
 392         unsigned int i, packets = header_length / 4;
 393
 394         /*
 395          * Compute the cycle of the last queued packet.
 396          * (We need only the four lowest bits for the SYT, so we can ignore
 397          * that bits 0-11 must wrap around at 3072.)
 398          */
 399         cycle += QUEUE_LENGTH - packets;
 400
 401         for (i = 0; i < packets; ++i)
 402                 queue_out_packet(s, ++cycle);
 403 }
 404
 405 static int queue_initial_skip_packets(struct amdtp_out_stream *s)
 406 {
 407         struct fw_iso_packet skip_packet = {
 408                 .skip = 1,
 409         };
 410         unsigned int i;
 411         int err;
 412
 413         for (i = 0; i < QUEUE_LENGTH; ++i) {
 414                 skip_packet.interrupt = IS_ALIGNED(s->packet_index + 1,
 415                                                    INTERRUPT_INTERVAL);
 416                 err = fw_iso_context_queue(s->context, &skip_packet, NULL, 0);
 417                 if (err < 0)
 418                         return err;
 419                 if (++s->packet_index >= QUEUE_LENGTH)
 420                         s->packet_index = 0;
 421         }
 422
 423         return 0;
 424 }
 425
 426 /**
 427  * amdtp_out_stream_start - start sending packets
 428  * @s: the AMDTP output stream to start
 429  * @channel: the isochronous channel on the bus
 430  * @speed: firewire speed code
 431  *
 432  * The stream cannot be started until it has been configured with
 433  * amdtp_out_stream_set_rate(), amdtp_out_stream_set_pcm(),
 434  * amdtp_out_stream_set_midi(), and amdtp_out_stream_set_format();
 435  * and it must be started before any PCM or MIDI device can be started.
 436  */
 437 int amdtp_out_stream_start(struct amdtp_out_stream *s, int channel, int speed)
 438 {
 439         static const struct {
 440                 unsigned int data_block;
 441                 unsigned int syt_offset;
 442         } initial_state[] = {
 443                 [CIP_SFC_32000]  = {  4, 3072 },
 444                 [CIP_SFC_48000]  = {  6, 1024 },
 445                 [CIP_SFC_96000]  = { 12, 1024 },
 446                 [CIP_SFC_192000] = { 24, 1024 },
 447                 [CIP_SFC_44100]  = {  0,   67 },
 448                 [CIP_SFC_88200]  = {  0,   67 },
 449                 [CIP_SFC_176400] = {  0,   67 },
 450         };
 451         int err;
 452
 453         mutex_lock(&s->mutex);
 454
 455         if (WARN_ON(!IS_ERR(s->context) ||
 456                     (!s->pcm_channels && !s->midi_ports))) {
 457                 err = -EBADFD;
 458                 goto err_unlock;
 459         }
 460
 461         s->data_block_state = initial_state[s->sfc].data_block;
 462         s->syt_offset_state = initial_state[s->sfc].syt_offset;
 463         s->last_syt_offset = TICKS_PER_CYCLE;
 464
 465         err = iso_packets_buffer_init(&s->buffer, s->unit, QUEUE_LENGTH,
 466                                       amdtp_out_stream_get_max_payload(s),
 467                                       DMA_TO_DEVICE);
 468         if (err < 0)
 469                 goto err_unlock;
 470
 471         s->context = fw_iso_context_create(fw_parent_device(s->unit)->card,
 472                                            FW_ISO_CONTEXT_TRANSMIT,
 473                                            channel, speed, 0,
 474                                            out_packet_callback, s);
 475         if (IS_ERR(s->context)) {
 476                 err = PTR_ERR(s->context);
 477                 if (err == -EBUSY)
 478                         dev_err(&s->unit->device,
 479                                 "no free output stream on this controller\n");
 480                 goto err_buffer;
 481         }
 482
 483         amdtp_out_stream_update(s);
 484
 485         s->packet_index = 0;
 486         s->data_block_counter = 0;
 487         err = queue_initial_skip_packets(s);
 488         if (err < 0)
 489                 goto err_context;
 490
 491         err = fw_iso_context_start(s->context, -1, 0, 0);
 492         if (err < 0)
 493                 goto err_context;
 494
 495         mutex_unlock(&s->mutex);
 496
 497         return 0;
 498
 499 err_context:
 500         fw_iso_context_destroy(s->context);
 501         s->context = ERR_PTR(-1);
 502 err_buffer:
 503         iso_packets_buffer_destroy(&s->buffer, s->unit);
 504 err_unlock:
 505         mutex_unlock(&s->mutex);
 506
 507         return err;
 508 }
 509 EXPORT_SYMBOL(amdtp_out_stream_start);
 510
 511 /**
 512  * amdtp_out_stream_update - update the stream after a bus reset
 513  * @s: the AMDTP output stream
 514  */
 515 void amdtp_out_stream_update(struct amdtp_out_stream *s)
 516 {
 517         ACCESS_ONCE(s->source_node_id_field) =
 518                 (fw_parent_device(s->unit)->card->node_id & 0x3f) << 24;
 519 }
 520 EXPORT_SYMBOL(amdtp_out_stream_update);
 521
 522 /**
 523  * amdtp_out_stream_stop - stop sending packets
 524  * @s: the AMDTP output stream to stop
 525  *
 526  * All PCM and MIDI devices of the stream must be stopped before the stream
 527  * itself can be stopped.
 528  */
 529 void amdtp_out_stream_stop(struct amdtp_out_stream *s)
 530 {
 531         mutex_lock(&s->mutex);
 532
 533         if (IS_ERR(s->context)) {
 534                 mutex_unlock(&s->mutex);
 535                 return;
 536         }
 537
 538         fw_iso_context_stop(s->context);
 539         fw_iso_context_destroy(s->context);
 540         s->context = ERR_PTR(-1);
 541         iso_packets_buffer_destroy(&s->buffer, s->unit);
 542
 543         mutex_unlock(&s->mutex);
 544 }
 545 EXPORT_SYMBOL(amdtp_out_stream_stop);
 546
 547 /**
 548  * amdtp_out_stream_pcm_abort - abort the running PCM device
 549  * @s: the AMDTP stream about to be stopped
 550  *
 551  * If the isochronous stream needs to be stopped asynchronously, call this
 552  * function first to stop the PCM device.
 553  */
 554 void amdtp_out_stream_pcm_abort(struct amdtp_out_stream *s)
 555 {
 556         struct snd_pcm_substream *pcm;
 557
 558         pcm = ACCESS_ONCE(s->pcm);
 559         if (pcm) {
 560                 snd_pcm_stream_lock_irq(pcm);
 561                 if (snd_pcm_running(pcm))
 562                         snd_pcm_stop(pcm, SNDRV_PCM_STATE_XRUN);
 563                 snd_pcm_stream_unlock_irq(pcm);
 564         }
 565 }
 566 EXPORT_SYMBOL(amdtp_out_stream_pcm_abort);