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