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         if (flags != CIP_NONBLOCKING)
  44                 return -EINVAL;
  45
  46         s->unit = fw_unit_get(unit);
  47         s->flags = flags;
  48         s->context = ERR_PTR(-1);
  49         mutex_init(&s->mutex);
  50
  51         return 0;
  52 }
  53 EXPORT_SYMBOL(amdtp_out_stream_init);
  54
  55 /**
  56  * amdtp_out_stream_destroy - free stream resources
  57  * @s: the AMDTP output stream to destroy
  58  */
  59 void amdtp_out_stream_destroy(struct amdtp_out_stream *s)
  60 {
  61         WARN_ON(!IS_ERR(s->context));
  62         mutex_destroy(&s->mutex);
  63         fw_unit_put(s->unit);
  64 }
  65 EXPORT_SYMBOL(amdtp_out_stream_destroy);
  66
  67 /**
  68  * amdtp_out_stream_set_rate - set the sample rate
  69  * @s: the AMDTP output stream to configure
  70  * @rate: the sample rate
  71  *
  72  * The sample rate must be set before the stream is started, and must not be
  73  * changed while the stream is running.
  74  */
  75 void amdtp_out_stream_set_rate(struct amdtp_out_stream *s, unsigned int rate)
  76 {
  77         static const struct {
  78                 unsigned int rate;
  79                 unsigned int syt_interval;
  80         } rate_info[] = {
  81                 [CIP_SFC_32000]  = {  32000,  8, },
  82                 [CIP_SFC_44100]  = {  44100,  8, },
  83                 [CIP_SFC_48000]  = {  48000,  8, },
  84                 [CIP_SFC_88200]  = {  88200, 16, },
  85                 [CIP_SFC_96000]  = {  96000, 16, },
  86                 [CIP_SFC_176400] = { 176400, 32, },
  87                 [CIP_SFC_192000] = { 192000, 32, },
  88         };
  89         unsigned int sfc;
  90
  91         if (WARN_ON(!IS_ERR(s->context)))
  92                 return;
  93
  94         for (sfc = 0; sfc < ARRAY_SIZE(rate_info); ++sfc)
  95                 if (rate_info[sfc].rate == rate) {
  96                         s->sfc = sfc;
  97                         s->syt_interval = rate_info[sfc].syt_interval;
  98                         return;
  99                 }
 100         WARN_ON(1);
 101 }
 102 EXPORT_SYMBOL(amdtp_out_stream_set_rate);
 103
 104 /**
 105  * amdtp_out_stream_get_max_payload - get the stream's packet size
 106  * @s: the AMDTP output stream
 107  *
 108  * This function must not be called before the stream has been configured
 109  * with amdtp_out_stream_set_hw_params(), amdtp_out_stream_set_pcm(), and
 110  * amdtp_out_stream_set_midi().
 111  */
 112 unsigned int amdtp_out_stream_get_max_payload(struct amdtp_out_stream *s)
 113 {
 114         static const unsigned int max_data_blocks[] = {
 115                 [CIP_SFC_32000]  =  4,
 116                 [CIP_SFC_44100]  =  6,
 117                 [CIP_SFC_48000]  =  6,
 118                 [CIP_SFC_88200]  = 12,
 119                 [CIP_SFC_96000]  = 12,
 120                 [CIP_SFC_176400] = 23,
 121                 [CIP_SFC_192000] = 24,
 122         };
 123
 124         s->data_block_quadlets = s->pcm_channels;
 125         s->data_block_quadlets += DIV_ROUND_UP(s->midi_ports, 8);
 126
 127         return 8 + max_data_blocks[s->sfc] * 4 * s->data_block_quadlets;
 128 }
 129 EXPORT_SYMBOL(amdtp_out_stream_get_max_payload);
 130
 131 static void amdtp_write_s16(struct amdtp_out_stream *s,
 132                             struct snd_pcm_substream *pcm,
 133                             __be32 *buffer, unsigned int frames);
 134 static void amdtp_write_s32(struct amdtp_out_stream *s,
 135                             struct snd_pcm_substream *pcm,
 136                             __be32 *buffer, unsigned int frames);
 137
 138 /**
 139  * amdtp_out_stream_set_pcm_format - set the PCM format
 140  * @s: the AMDTP output stream to configure
 141  * @format: the format of the ALSA PCM device
 142  *
 143  * The sample format must be set before the stream is started, and must not be
 144  * changed while the stream is running.
 145  */
 146 void amdtp_out_stream_set_pcm_format(struct amdtp_out_stream *s,
 147                                      snd_pcm_format_t format)
 148 {
 149         if (WARN_ON(!IS_ERR(s->context)))
 150                 return;
 151
 152         switch (format) {
 153         default:
 154                 WARN_ON(1);
 155                 /* fall through */
 156         case SNDRV_PCM_FORMAT_S16:
 157                 s->transfer_samples = amdtp_write_s16;
 158                 break;
 159         case SNDRV_PCM_FORMAT_S32:
 160                 s->transfer_samples = amdtp_write_s32;
 161                 break;
 162         }
 163 }
 164 EXPORT_SYMBOL(amdtp_out_stream_set_pcm_format);
 165
 166 static unsigned int calculate_data_blocks(struct amdtp_out_stream *s)
 167 {
 168         unsigned int phase, data_blocks;
 169
 170         if (!cip_sfc_is_base_44100(s->sfc)) {
 171                 /* Sample_rate / 8000 is an integer, and precomputed. */
 172                 data_blocks = s->data_block_state;
 173         } else {
 174                 phase = s->data_block_state;
 175
 176                 /*
 177                  * This calculates the number of data blocks per packet so that
 178                  * 1) the overall rate is correct and exactly synchronized to
 179                  *    the bus clock, and
 180                  * 2) packets with a rounded-up number of blocks occur as early
 181                  *    as possible in the sequence (to prevent underruns of the
 182                  *    device's buffer).
 183                  */
 184                 if (s->sfc == CIP_SFC_44100)
 185                         /* 6 6 5 6 5 6 5 ... */
 186                         data_blocks = 5 + ((phase & 1) ^
 187                                            (phase == 0 || phase >= 40));
 188                 else
 189                         /* 12 11 11 11 11 ... or 23 22 22 22 22 ... */
 190                         data_blocks = 11 * (s->sfc >> 1) + (phase == 0);
 191                 if (++phase >= (80 >> (s->sfc >> 1)))
 192                         phase = 0;
 193                 s->data_block_state = phase;
 194         }
 195
 196         return data_blocks;
 197 }
 198
 199 static unsigned int calculate_syt(struct amdtp_out_stream *s,
 200                                   unsigned int cycle)
 201 {
 202         unsigned int syt_offset, phase, index, syt;
 203
 204         if (s->last_syt_offset < TICKS_PER_CYCLE) {
 205                 if (!cip_sfc_is_base_44100(s->sfc))
 206                         syt_offset = s->last_syt_offset + s->syt_offset_state;
 207                 else {
 208                 /*
 209                  * The time, in ticks, of the n'th SYT_INTERVAL sample is:
 210                  *   n * SYT_INTERVAL * 24576000 / sample_rate
 211                  * Modulo TICKS_PER_CYCLE, the difference between successive
 212                  * elements is about 1386.23.  Rounding the results of this
 213                  * formula to the SYT precision results in a sequence of
 214                  * differences that begins with:
 215                  *   1386 1386 1387 1386 1386 1386 1387 1386 1386 1386 1387 ...
 216                  * This code generates _exactly_ the same sequence.
 217                  */
 218                         phase = s->syt_offset_state;
 219                         index = phase % 13;
 220                         syt_offset = s->last_syt_offset;
 221                         syt_offset += 1386 + ((index && !(index & 3)) ||
 222                                               phase == 146);
 223                         if (++phase >= 147)
 224                                 phase = 0;
 225                         s->syt_offset_state = phase;
 226                 }
 227         } else
 228                 syt_offset = s->last_syt_offset - TICKS_PER_CYCLE;
 229         s->last_syt_offset = syt_offset;
 230
 231         syt_offset += TRANSFER_DELAY_TICKS - TICKS_PER_CYCLE;
 232         syt = (cycle + syt_offset / TICKS_PER_CYCLE) << 12;
 233         syt += syt_offset % TICKS_PER_CYCLE;
 234
 235         return syt & 0xffff;
 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 data_blocks, syt, ptr;
 316         struct snd_pcm_substream *pcm;
 317         struct fw_iso_packet packet;
 318         int err;
 319
 320         data_blocks = calculate_data_blocks(s);
 321         syt = calculate_syt(s, cycle);
 322
 323         buffer = s->buffer.packets[s->packet_counter].buffer;
 324         buffer[0] = cpu_to_be32(ACCESS_ONCE(s->source_node_id_field) |
 325                                 (s->data_block_quadlets << 16) |
 326                                 s->data_block_counter);
 327         buffer[1] = cpu_to_be32(CIP_EOH | CIP_FMT_AM | AMDTP_FDF_AM824 |
 328                                 (s->sfc << AMDTP_FDF_SFC_SHIFT) | syt);
 329         buffer += 2;
 330
 331         pcm = ACCESS_ONCE(s->pcm);
 332         if (pcm)
 333                 s->transfer_samples(s, pcm, buffer, data_blocks);
 334         else
 335                 amdtp_fill_pcm_silence(s, buffer, data_blocks);
 336         if (s->midi_ports)
 337                 amdtp_fill_midi(s, buffer, data_blocks);
 338
 339         s->data_block_counter = (s->data_block_counter + data_blocks) & 0xff;
 340
 341         packet.payload_length = 8 + data_blocks * 4 * s->data_block_quadlets;
 342         packet.interrupt = IS_ALIGNED(s->packet_counter + 1,
 343                                       INTERRUPT_INTERVAL);
 344         packet.skip = 0;
 345         packet.tag = TAG_CIP;
 346         packet.sy = 0;
 347         packet.header_length = 0;
 348
 349         err = fw_iso_context_queue(s->context, &packet, &s->buffer.iso_buffer,
 350                                    s->buffer.packets[s->packet_counter].offset);
 351         if (err < 0)
 352                 dev_err(&s->unit->device, "queueing error: %d\n", err);
 353
 354         if (++s->packet_counter >= QUEUE_LENGTH)
 355                 s->packet_counter = 0;
 356
 357         if (pcm) {
 358                 ptr = s->pcm_buffer_pointer + data_blocks;
 359                 if (ptr >= pcm->runtime->buffer_size)
 360                         ptr -= pcm->runtime->buffer_size;
 361                 ACCESS_ONCE(s->pcm_buffer_pointer) = ptr;
 362
 363                 s->pcm_period_pointer += data_blocks;
 364                 if (s->pcm_period_pointer >= pcm->runtime->period_size) {
 365                         s->pcm_period_pointer -= pcm->runtime->period_size;
 366                         snd_pcm_period_elapsed(pcm);
 367                 }
 368         }
 369 }
 370
 371 static void out_packet_callback(struct fw_iso_context *context, u32 cycle,
 372                                 size_t header_length, void *header, void *data)
 373 {
 374         struct amdtp_out_stream *s = data;
 375         unsigned int i, packets = header_length / 4;
 376
 377         /*
 378          * Compute the cycle of the last queued packet.
 379          * (We need only the four lowest bits for the SYT, so we can ignore
 380          * that bits 0-11 must wrap around at 3072.)
 381          */
 382         cycle += QUEUE_LENGTH - packets;
 383
 384         for (i = 0; i < packets; ++i)
 385                 queue_out_packet(s, ++cycle);
 386 }
 387
 388 static int queue_initial_skip_packets(struct amdtp_out_stream *s)
 389 {
 390         struct fw_iso_packet skip_packet = {
 391                 .skip = 1,
 392         };
 393         unsigned int i;
 394         int err;
 395
 396         for (i = 0; i < QUEUE_LENGTH; ++i) {
 397                 skip_packet.interrupt = IS_ALIGNED(s->packet_counter + 1,
 398                                                    INTERRUPT_INTERVAL);
 399                 err = fw_iso_context_queue(s->context, &skip_packet, NULL, 0);
 400                 if (err < 0)
 401                         return err;
 402                 if (++s->packet_counter >= QUEUE_LENGTH)
 403                         s->packet_counter = 0;
 404         }
 405
 406         return 0;
 407 }
 408
 409 /**
 410  * amdtp_out_stream_start - start sending packets
 411  * @s: the AMDTP output stream to start
 412  * @channel: the isochronous channel on the bus
 413  * @speed: firewire speed code
 414  *
 415  * The stream cannot be started until it has been configured with
 416  * amdtp_out_stream_set_hw_params(), amdtp_out_stream_set_pcm(), and
 417  * amdtp_out_stream_set_midi(); and it must be started before any
 418  * PCM or MIDI device can be started.
 419  */
 420 int amdtp_out_stream_start(struct amdtp_out_stream *s, int channel, int speed)
 421 {
 422         static const struct {
 423                 unsigned int data_block;
 424                 unsigned int syt_offset;
 425         } initial_state[] = {
 426                 [CIP_SFC_32000]  = {  4, 3072 },
 427                 [CIP_SFC_48000]  = {  6, 1024 },
 428                 [CIP_SFC_96000]  = { 12, 1024 },
 429                 [CIP_SFC_192000] = { 24, 1024 },
 430                 [CIP_SFC_44100]  = {  0,   67 },
 431                 [CIP_SFC_88200]  = {  0,   67 },
 432                 [CIP_SFC_176400] = {  0,   67 },
 433         };
 434         int err;
 435
 436         mutex_lock(&s->mutex);
 437
 438         if (WARN_ON(!IS_ERR(s->context) ||
 439                     (!s->pcm_channels && !s->midi_ports))) {
 440                 err = -EBADFD;
 441                 goto err_unlock;
 442         }
 443
 444         s->data_block_state = initial_state[s->sfc].data_block;
 445         s->syt_offset_state = initial_state[s->sfc].syt_offset;
 446         s->last_syt_offset = TICKS_PER_CYCLE;
 447
 448         err = iso_packets_buffer_init(&s->buffer, s->unit, QUEUE_LENGTH,
 449                                       amdtp_out_stream_get_max_payload(s),
 450                                       DMA_TO_DEVICE);
 451         if (err < 0)
 452                 goto err_unlock;
 453
 454         s->context = fw_iso_context_create(fw_parent_device(s->unit)->card,
 455                                            FW_ISO_CONTEXT_TRANSMIT,
 456                                            channel, speed, 0,
 457                                            out_packet_callback, s);
 458         if (IS_ERR(s->context)) {
 459                 err = PTR_ERR(s->context);
 460                 if (err == -EBUSY)
 461                         dev_err(&s->unit->device,
 462                                 "no free output stream on this controller\n");
 463                 goto err_buffer;
 464         }
 465
 466         amdtp_out_stream_update(s);
 467
 468         s->packet_counter = 0;
 469         s->data_block_counter = 0;
 470         err = queue_initial_skip_packets(s);
 471         if (err < 0)
 472                 goto err_context;
 473
 474         err = fw_iso_context_start(s->context, -1, 0, 0);
 475         if (err < 0)
 476                 goto err_context;
 477
 478         mutex_unlock(&s->mutex);
 479
 480         return 0;
 481
 482 err_context:
 483         fw_iso_context_destroy(s->context);
 484         s->context = ERR_PTR(-1);
 485 err_buffer:
 486         iso_packets_buffer_destroy(&s->buffer, s->unit);
 487 err_unlock:
 488         mutex_unlock(&s->mutex);
 489
 490         return err;
 491 }
 492 EXPORT_SYMBOL(amdtp_out_stream_start);
 493
 494 /**
 495  * amdtp_out_stream_update - update the stream after a bus reset
 496  * @s: the AMDTP output stream
 497  */
 498 void amdtp_out_stream_update(struct amdtp_out_stream *s)
 499 {
 500         ACCESS_ONCE(s->source_node_id_field) =
 501                 (fw_parent_device(s->unit)->card->node_id & 0x3f) << 24;
 502 }
 503 EXPORT_SYMBOL(amdtp_out_stream_update);
 504
 505 /**
 506  * amdtp_out_stream_stop - stop sending packets
 507  * @s: the AMDTP output stream to stop
 508  *
 509  * All PCM and MIDI devices of the stream must be stopped before the stream
 510  * itself can be stopped.
 511  */
 512 void amdtp_out_stream_stop(struct amdtp_out_stream *s)
 513 {
 514         mutex_lock(&s->mutex);
 515
 516         if (IS_ERR(s->context)) {
 517                 mutex_unlock(&s->mutex);
 518                 return;
 519         }
 520
 521         fw_iso_context_stop(s->context);
 522         fw_iso_context_destroy(s->context);
 523         s->context = ERR_PTR(-1);
 524         iso_packets_buffer_destroy(&s->buffer, s->unit);
 525
 526         mutex_unlock(&s->mutex);
 527 }
 528 EXPORT_SYMBOL(amdtp_out_stream_stop);
 529
 530 /**
 531  * amdtp_out_stream_pcm_abort - abort the running PCM device
 532  * @s: the AMDTP stream about to be stopped
 533  *
 534  * If the isochronous stream needs to be stopped asynchronously, call this
 535  * function first to stop the PCM device.
 536  */
 537 void amdtp_out_stream_pcm_abort(struct amdtp_out_stream *s)
 538 {
 539         struct snd_pcm_substream *pcm;
 540
 541         pcm = ACCESS_ONCE(s->pcm);
 542         if (pcm) {
 543                 snd_pcm_stream_lock_irq(pcm);
 544                 if (snd_pcm_running(pcm))
 545                         snd_pcm_stop(pcm, SNDRV_PCM_STATE_XRUN);
 546                 snd_pcm_stream_unlock_irq(pcm);
 547         }
 548 }
 549 EXPORT_SYMBOL(amdtp_out_stream_pcm_abort);