linux/sound/firewire/amdtp.c
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   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 ┬Ás */
  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
  34static void pcm_period_tasklet(unsigned long data);
  35
  36/**
  37 * amdtp_out_stream_init - initialize an AMDTP output stream structure
  38 * @s: the AMDTP output stream to initialize
  39 * @unit: the target of the stream
  40 * @flags: the packet transmission method to use
  41 */
  42int amdtp_out_stream_init(struct amdtp_out_stream *s, struct fw_unit *unit,
  43                          enum cip_out_flags flags)
  44{
  45        if (flags != CIP_NONBLOCKING)
  46                return -EINVAL;
  47
  48        s->unit = fw_unit_get(unit);
  49        s->flags = flags;
  50        s->context = ERR_PTR(-1);
  51        mutex_init(&s->mutex);
  52        tasklet_init(&s->period_tasklet, pcm_period_tasklet, (unsigned long)s);
  53        s->packet_index = 0;
  54
  55        return 0;
  56}
  57EXPORT_SYMBOL(amdtp_out_stream_init);
  58
  59/**
  60 * amdtp_out_stream_destroy - free stream resources
  61 * @s: the AMDTP output stream to destroy
  62 */
  63void amdtp_out_stream_destroy(struct amdtp_out_stream *s)
  64{
  65        WARN_ON(!IS_ERR(s->context));
  66        mutex_destroy(&s->mutex);
  67        fw_unit_put(s->unit);
  68}
  69EXPORT_SYMBOL(amdtp_out_stream_destroy);
  70
  71/**
  72 * amdtp_out_stream_set_rate - set the sample rate
  73 * @s: the AMDTP output stream to configure
  74 * @rate: the sample rate
  75 *
  76 * The sample rate must be set before the stream is started, and must not be
  77 * changed while the stream is running.
  78 */
  79void amdtp_out_stream_set_rate(struct amdtp_out_stream *s, unsigned int rate)
  80{
  81        static const struct {
  82                unsigned int rate;
  83                unsigned int syt_interval;
  84        } rate_info[] = {
  85                [CIP_SFC_32000]  = {  32000,  8, },
  86                [CIP_SFC_44100]  = {  44100,  8, },
  87                [CIP_SFC_48000]  = {  48000,  8, },
  88                [CIP_SFC_88200]  = {  88200, 16, },
  89                [CIP_SFC_96000]  = {  96000, 16, },
  90                [CIP_SFC_176400] = { 176400, 32, },
  91                [CIP_SFC_192000] = { 192000, 32, },
  92        };
  93        unsigned int sfc;
  94
  95        if (WARN_ON(!IS_ERR(s->context)))
  96                return;
  97
  98        for (sfc = 0; sfc < ARRAY_SIZE(rate_info); ++sfc)
  99                if (rate_info[sfc].rate == rate) {
 100                        s->sfc = sfc;
 101                        s->syt_interval = rate_info[sfc].syt_interval;
 102                        return;
 103                }
 104        WARN_ON(1);
 105}
 106EXPORT_SYMBOL(amdtp_out_stream_set_rate);
 107
 108/**
 109 * amdtp_out_stream_get_max_payload - get the stream's packet size
 110 * @s: the AMDTP output stream
 111 *
 112 * This function must not be called before the stream has been configured
 113 * with amdtp_out_stream_set_hw_params(), amdtp_out_stream_set_pcm(), and
 114 * amdtp_out_stream_set_midi().
 115 */
 116unsigned int amdtp_out_stream_get_max_payload(struct amdtp_out_stream *s)
 117{
 118        static const unsigned int max_data_blocks[] = {
 119                [CIP_SFC_32000]  =  4,
 120                [CIP_SFC_44100]  =  6,
 121                [CIP_SFC_48000]  =  6,
 122                [CIP_SFC_88200]  = 12,
 123                [CIP_SFC_96000]  = 12,
 124                [CIP_SFC_176400] = 23,
 125                [CIP_SFC_192000] = 24,
 126        };
 127
 128        s->data_block_quadlets = s->pcm_channels;
 129        s->data_block_quadlets += DIV_ROUND_UP(s->midi_ports, 8);
 130
 131        return 8 + max_data_blocks[s->sfc] * 4 * s->data_block_quadlets;
 132}
 133EXPORT_SYMBOL(amdtp_out_stream_get_max_payload);
 134
 135static void amdtp_write_s16(struct amdtp_out_stream *s,
 136                            struct snd_pcm_substream *pcm,
 137                            __be32 *buffer, unsigned int frames);
 138static void amdtp_write_s32(struct amdtp_out_stream *s,
 139                            struct snd_pcm_substream *pcm,
 140                            __be32 *buffer, unsigned int frames);
 141
 142/**
 143 * amdtp_out_stream_set_pcm_format - set the PCM format
 144 * @s: the AMDTP output stream to configure
 145 * @format: the format of the ALSA PCM device
 146 *
 147 * The sample format must be set before the stream is started, and must not be
 148 * changed while the stream is running.
 149 */
 150void amdtp_out_stream_set_pcm_format(struct amdtp_out_stream *s,
 151                                     snd_pcm_format_t format)
 152{
 153        if (WARN_ON(!IS_ERR(s->context)))
 154                return;
 155
 156        switch (format) {
 157        default:
 158                WARN_ON(1);
 159                /* fall through */
 160        case SNDRV_PCM_FORMAT_S16:
 161                s->transfer_samples = amdtp_write_s16;
 162                break;
 163        case SNDRV_PCM_FORMAT_S32:
 164                s->transfer_samples = amdtp_write_s32;
 165                break;
 166        }
 167}
 168EXPORT_SYMBOL(amdtp_out_stream_set_pcm_format);
 169
 170/**
 171 * amdtp_out_stream_pcm_prepare - prepare PCM device for running
 172 * @s: the AMDTP output stream
 173 *
 174 * This function should be called from the PCM device's .prepare callback.
 175 */
 176void amdtp_out_stream_pcm_prepare(struct amdtp_out_stream *s)
 177{
 178        tasklet_kill(&s->period_tasklet);
 179        s->pcm_buffer_pointer = 0;
 180        s->pcm_period_pointer = 0;
 181        s->pointer_flush = true;
 182}
 183EXPORT_SYMBOL(amdtp_out_stream_pcm_prepare);
 184
 185static unsigned int calculate_data_blocks(struct amdtp_out_stream *s)
 186{
 187        unsigned int phase, data_blocks;
 188
 189        if (!cip_sfc_is_base_44100(s->sfc)) {
 190                /* Sample_rate / 8000 is an integer, and precomputed. */
 191                data_blocks = s->data_block_state;
 192        } else {
 193                phase = s->data_block_state;
 194
 195                /*
 196                 * This calculates the number of data blocks per packet so that
 197                 * 1) the overall rate is correct and exactly synchronized to
 198                 *    the bus clock, and
 199                 * 2) packets with a rounded-up number of blocks occur as early
 200                 *    as possible in the sequence (to prevent underruns of the
 201                 *    device's buffer).
 202                 */
 203                if (s->sfc == CIP_SFC_44100)
 204                        /* 6 6 5 6 5 6 5 ... */
 205                        data_blocks = 5 + ((phase & 1) ^
 206                                           (phase == 0 || phase >= 40));
 207                else
 208                        /* 12 11 11 11 11 ... or 23 22 22 22 22 ... */
 209                        data_blocks = 11 * (s->sfc >> 1) + (phase == 0);
 210                if (++phase >= (80 >> (s->sfc >> 1)))
 211                        phase = 0;
 212                s->data_block_state = phase;
 213        }
 214
 215        return data_blocks;
 216}
 217
 218static unsigned int calculate_syt(struct amdtp_out_stream *s,
 219                                  unsigned int cycle)
 220{
 221        unsigned int syt_offset, phase, index, syt;
 222
 223        if (s->last_syt_offset < TICKS_PER_CYCLE) {
 224                if (!cip_sfc_is_base_44100(s->sfc))
 225                        syt_offset = s->last_syt_offset + s->syt_offset_state;
 226                else {
 227                /*
 228                 * The time, in ticks, of the n'th SYT_INTERVAL sample is:
 229                 *   n * SYT_INTERVAL * 24576000 / sample_rate
 230                 * Modulo TICKS_PER_CYCLE, the difference between successive
 231                 * elements is about 1386.23.  Rounding the results of this
 232                 * formula to the SYT precision results in a sequence of
 233                 * differences that begins with:
 234                 *   1386 1386 1387 1386 1386 1386 1387 1386 1386 1386 1387 ...
 235                 * This code generates _exactly_ the same sequence.
 236                 */
 237                        phase = s->syt_offset_state;
 238                        index = phase % 13;
 239                        syt_offset = s->last_syt_offset;
 240                        syt_offset += 1386 + ((index && !(index & 3)) ||
 241                                              phase == 146);
 242                        if (++phase >= 147)
 243                                phase = 0;
 244                        s->syt_offset_state = phase;
 245                }
 246        } else
 247                syt_offset = s->last_syt_offset - TICKS_PER_CYCLE;
 248        s->last_syt_offset = syt_offset;
 249
 250        if (syt_offset < TICKS_PER_CYCLE) {
 251                syt_offset += TRANSFER_DELAY_TICKS - TICKS_PER_CYCLE;
 252                syt = (cycle + syt_offset / TICKS_PER_CYCLE) << 12;
 253                syt += syt_offset % TICKS_PER_CYCLE;
 254
 255                return syt & 0xffff;
 256        } else {
 257                return 0xffff; /* no info */
 258        }
 259}
 260
 261static void amdtp_write_s32(struct amdtp_out_stream *s,
 262                            struct snd_pcm_substream *pcm,
 263                            __be32 *buffer, unsigned int frames)
 264{
 265        struct snd_pcm_runtime *runtime = pcm->runtime;
 266        unsigned int channels, remaining_frames, frame_step, i, c;
 267        const u32 *src;
 268
 269        channels = s->pcm_channels;
 270        src = (void *)runtime->dma_area +
 271                        s->pcm_buffer_pointer * (runtime->frame_bits / 8);
 272        remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer;
 273        frame_step = s->data_block_quadlets - channels;
 274
 275        for (i = 0; i < frames; ++i) {
 276                for (c = 0; c < channels; ++c) {
 277                        *buffer = cpu_to_be32((*src >> 8) | 0x40000000);
 278                        src++;
 279                        buffer++;
 280                }
 281                buffer += frame_step;
 282                if (--remaining_frames == 0)
 283                        src = (void *)runtime->dma_area;
 284        }
 285}
 286
 287static void amdtp_write_s16(struct amdtp_out_stream *s,
 288                            struct snd_pcm_substream *pcm,
 289                            __be32 *buffer, unsigned int frames)
 290{
 291        struct snd_pcm_runtime *runtime = pcm->runtime;
 292        unsigned int channels, remaining_frames, frame_step, i, c;
 293        const u16 *src;
 294
 295        channels = s->pcm_channels;
 296        src = (void *)runtime->dma_area +
 297                        s->pcm_buffer_pointer * (runtime->frame_bits / 8);
 298        remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer;
 299        frame_step = s->data_block_quadlets - channels;
 300
 301        for (i = 0; i < frames; ++i) {
 302                for (c = 0; c < channels; ++c) {
 303                        *buffer = cpu_to_be32((*src << 8) | 0x40000000);
 304                        src++;
 305                        buffer++;
 306                }
 307                buffer += frame_step;
 308                if (--remaining_frames == 0)
 309                        src = (void *)runtime->dma_area;
 310        }
 311}
 312
 313static void amdtp_fill_pcm_silence(struct amdtp_out_stream *s,
 314                                   __be32 *buffer, unsigned int frames)
 315{
 316        unsigned int i, c;
 317
 318        for (i = 0; i < frames; ++i) {
 319                for (c = 0; c < s->pcm_channels; ++c)
 320                        buffer[c] = cpu_to_be32(0x40000000);
 321                buffer += s->data_block_quadlets;
 322        }
 323}
 324
 325static void amdtp_fill_midi(struct amdtp_out_stream *s,
 326                            __be32 *buffer, unsigned int frames)
 327{
 328        unsigned int i;
 329
 330        for (i = 0; i < frames; ++i)
 331                buffer[s->pcm_channels + i * s->data_block_quadlets] =
 332                                                cpu_to_be32(0x80000000);
 333}
 334
 335static void queue_out_packet(struct amdtp_out_stream *s, unsigned int cycle)
 336{
 337        __be32 *buffer;
 338        unsigned int index, data_blocks, syt, ptr;
 339        struct snd_pcm_substream *pcm;
 340        struct fw_iso_packet packet;
 341        int err;
 342
 343        if (s->packet_index < 0)
 344                return;
 345        index = s->packet_index;
 346
 347        data_blocks = calculate_data_blocks(s);
 348        syt = calculate_syt(s, cycle);
 349
 350        buffer = s->buffer.packets[index].buffer;
 351        buffer[0] = cpu_to_be32(ACCESS_ONCE(s->source_node_id_field) |
 352                                (s->data_block_quadlets << 16) |
 353                                s->data_block_counter);
 354        buffer[1] = cpu_to_be32(CIP_EOH | CIP_FMT_AM | AMDTP_FDF_AM824 |
 355                                (s->sfc << AMDTP_FDF_SFC_SHIFT) | syt);
 356        buffer += 2;
 357
 358        pcm = ACCESS_ONCE(s->pcm);
 359        if (pcm)
 360                s->transfer_samples(s, pcm, buffer, data_blocks);
 361        else
 362                amdtp_fill_pcm_silence(s, buffer, data_blocks);
 363        if (s->midi_ports)
 364                amdtp_fill_midi(s, buffer, data_blocks);
 365
 366        s->data_block_counter = (s->data_block_counter + data_blocks) & 0xff;
 367
 368        packet.payload_length = 8 + data_blocks * 4 * s->data_block_quadlets;
 369        packet.interrupt = IS_ALIGNED(index + 1, INTERRUPT_INTERVAL);
 370        packet.skip = 0;
 371        packet.tag = TAG_CIP;
 372        packet.sy = 0;
 373        packet.header_length = 0;
 374
 375        err = fw_iso_context_queue(s->context, &packet, &s->buffer.iso_buffer,
 376                                   s->buffer.packets[index].offset);
 377        if (err < 0) {
 378                dev_err(&s->unit->device, "queueing error: %d\n", err);
 379                s->packet_index = -1;
 380                amdtp_out_stream_pcm_abort(s);
 381                return;
 382        }
 383
 384        if (++index >= QUEUE_LENGTH)
 385                index = 0;
 386        s->packet_index = index;
 387
 388        if (pcm) {
 389                ptr = s->pcm_buffer_pointer + data_blocks;
 390                if (ptr >= pcm->runtime->buffer_size)
 391                        ptr -= pcm->runtime->buffer_size;
 392                ACCESS_ONCE(s->pcm_buffer_pointer) = ptr;
 393
 394                s->pcm_period_pointer += data_blocks;
 395                if (s->pcm_period_pointer >= pcm->runtime->period_size) {
 396                        s->pcm_period_pointer -= pcm->runtime->period_size;
 397                        s->pointer_flush = false;
 398                        tasklet_hi_schedule(&s->period_tasklet);
 399                }
 400        }
 401}
 402
 403static void pcm_period_tasklet(unsigned long data)
 404{
 405        struct amdtp_out_stream *s = (void *)data;
 406        struct snd_pcm_substream *pcm = ACCESS_ONCE(s->pcm);
 407
 408        if (pcm)
 409                snd_pcm_period_elapsed(pcm);
 410}
 411
 412static void out_packet_callback(struct fw_iso_context *context, u32 cycle,
 413                                size_t header_length, void *header, void *data)
 414{
 415        struct amdtp_out_stream *s = data;
 416        unsigned int i, packets = header_length / 4;
 417
 418        /*
 419         * Compute the cycle of the last queued packet.
 420         * (We need only the four lowest bits for the SYT, so we can ignore
 421         * that bits 0-11 must wrap around at 3072.)
 422         */
 423        cycle += QUEUE_LENGTH - packets;
 424
 425        for (i = 0; i < packets; ++i)
 426                queue_out_packet(s, ++cycle);
 427        fw_iso_context_queue_flush(s->context);
 428}
 429
 430static int queue_initial_skip_packets(struct amdtp_out_stream *s)
 431{
 432        struct fw_iso_packet skip_packet = {
 433                .skip = 1,
 434        };
 435        unsigned int i;
 436        int err;
 437
 438        for (i = 0; i < QUEUE_LENGTH; ++i) {
 439                skip_packet.interrupt = IS_ALIGNED(s->packet_index + 1,
 440                                                   INTERRUPT_INTERVAL);
 441                err = fw_iso_context_queue(s->context, &skip_packet, NULL, 0);
 442                if (err < 0)
 443                        return err;
 444                if (++s->packet_index >= QUEUE_LENGTH)
 445                        s->packet_index = 0;
 446        }
 447
 448        return 0;
 449}
 450
 451/**
 452 * amdtp_out_stream_start - start sending packets
 453 * @s: the AMDTP output stream to start
 454 * @channel: the isochronous channel on the bus
 455 * @speed: firewire speed code
 456 *
 457 * The stream cannot be started until it has been configured with
 458 * amdtp_out_stream_set_hw_params(), amdtp_out_stream_set_pcm(), and
 459 * amdtp_out_stream_set_midi(); and it must be started before any
 460 * PCM or MIDI device can be started.
 461 */
 462int amdtp_out_stream_start(struct amdtp_out_stream *s, int channel, int speed)
 463{
 464        static const struct {
 465                unsigned int data_block;
 466                unsigned int syt_offset;
 467        } initial_state[] = {
 468                [CIP_SFC_32000]  = {  4, 3072 },
 469                [CIP_SFC_48000]  = {  6, 1024 },
 470                [CIP_SFC_96000]  = { 12, 1024 },
 471                [CIP_SFC_192000] = { 24, 1024 },
 472                [CIP_SFC_44100]  = {  0,   67 },
 473                [CIP_SFC_88200]  = {  0,   67 },
 474                [CIP_SFC_176400] = {  0,   67 },
 475        };
 476        int err;
 477
 478        mutex_lock(&s->mutex);
 479
 480        if (WARN_ON(!IS_ERR(s->context) ||
 481                    (!s->pcm_channels && !s->midi_ports))) {
 482                err = -EBADFD;
 483                goto err_unlock;
 484        }
 485
 486        s->data_block_state = initial_state[s->sfc].data_block;
 487        s->syt_offset_state = initial_state[s->sfc].syt_offset;
 488        s->last_syt_offset = TICKS_PER_CYCLE;
 489
 490        err = iso_packets_buffer_init(&s->buffer, s->unit, QUEUE_LENGTH,
 491                                      amdtp_out_stream_get_max_payload(s),
 492                                      DMA_TO_DEVICE);
 493        if (err < 0)
 494                goto err_unlock;
 495
 496        s->context = fw_iso_context_create(fw_parent_device(s->unit)->card,
 497                                           FW_ISO_CONTEXT_TRANSMIT,
 498                                           channel, speed, 0,
 499                                           out_packet_callback, s);
 500        if (IS_ERR(s->context)) {
 501                err = PTR_ERR(s->context);
 502                if (err == -EBUSY)
 503                        dev_err(&s->unit->device,
 504                                "no free output stream on this controller\n");
 505                goto err_buffer;
 506        }
 507
 508        amdtp_out_stream_update(s);
 509
 510        s->packet_index = 0;
 511        s->data_block_counter = 0;
 512        err = queue_initial_skip_packets(s);
 513        if (err < 0)
 514                goto err_context;
 515
 516        err = fw_iso_context_start(s->context, -1, 0, 0);
 517        if (err < 0)
 518                goto err_context;
 519
 520        mutex_unlock(&s->mutex);
 521
 522        return 0;
 523
 524err_context:
 525        fw_iso_context_destroy(s->context);
 526        s->context = ERR_PTR(-1);
 527err_buffer:
 528        iso_packets_buffer_destroy(&s->buffer, s->unit);
 529err_unlock:
 530        mutex_unlock(&s->mutex);
 531
 532        return err;
 533}
 534EXPORT_SYMBOL(amdtp_out_stream_start);
 535
 536/**
 537 * amdtp_out_stream_pcm_pointer - get the PCM buffer position
 538 * @s: the AMDTP output stream that transports the PCM data
 539 *
 540 * Returns the current buffer position, in frames.
 541 */
 542unsigned long amdtp_out_stream_pcm_pointer(struct amdtp_out_stream *s)
 543{
 544        /* this optimization is allowed to be racy */
 545        if (s->pointer_flush)
 546                fw_iso_context_flush_completions(s->context);
 547        else
 548                s->pointer_flush = true;
 549
 550        return ACCESS_ONCE(s->pcm_buffer_pointer);
 551}
 552EXPORT_SYMBOL(amdtp_out_stream_pcm_pointer);
 553
 554/**
 555 * amdtp_out_stream_update - update the stream after a bus reset
 556 * @s: the AMDTP output stream
 557 */
 558void amdtp_out_stream_update(struct amdtp_out_stream *s)
 559{
 560        ACCESS_ONCE(s->source_node_id_field) =
 561                (fw_parent_device(s->unit)->card->node_id & 0x3f) << 24;
 562}
 563EXPORT_SYMBOL(amdtp_out_stream_update);
 564
 565/**
 566 * amdtp_out_stream_stop - stop sending packets
 567 * @s: the AMDTP output stream to stop
 568 *
 569 * All PCM and MIDI devices of the stream must be stopped before the stream
 570 * itself can be stopped.
 571 */
 572void amdtp_out_stream_stop(struct amdtp_out_stream *s)
 573{
 574        mutex_lock(&s->mutex);
 575
 576        if (IS_ERR(s->context)) {
 577                mutex_unlock(&s->mutex);
 578                return;
 579        }
 580
 581        tasklet_kill(&s->period_tasklet);
 582        fw_iso_context_stop(s->context);
 583        fw_iso_context_destroy(s->context);
 584        s->context = ERR_PTR(-1);
 585        iso_packets_buffer_destroy(&s->buffer, s->unit);
 586
 587        mutex_unlock(&s->mutex);
 588}
 589EXPORT_SYMBOL(amdtp_out_stream_stop);
 590
 591/**
 592 * amdtp_out_stream_pcm_abort - abort the running PCM device
 593 * @s: the AMDTP stream about to be stopped
 594 *
 595 * If the isochronous stream needs to be stopped asynchronously, call this
 596 * function first to stop the PCM device.
 597 */
 598void amdtp_out_stream_pcm_abort(struct amdtp_out_stream *s)
 599{
 600        struct snd_pcm_substream *pcm;
 601
 602        pcm = ACCESS_ONCE(s->pcm);
 603        if (pcm) {
 604                snd_pcm_stream_lock_irq(pcm);
 605                if (snd_pcm_running(pcm))
 606                        snd_pcm_stop(pcm, SNDRV_PCM_STATE_XRUN);
 607                snd_pcm_stream_unlock_irq(pcm);
 608        }
 609}
 610EXPORT_SYMBOL(amdtp_out_stream_pcm_abort);
 611
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