sound/firewire/amdtp-stream.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Audio and Music Data Transmission Protocol (IEC 61883-6) streams
   4  * with Common Isochronous Packet (IEC 61883-1) headers
   5  *
   6  * Copyright (c) Clemens Ladisch <clemens@ladisch.de>
   7  */
   8
   9 #include <linux/device.h>
  10 #include <linux/err.h>
  11 #include <linux/firewire.h>
  12 #include <linux/firewire-constants.h>
  13 #include <linux/module.h>
  14 #include <linux/slab.h>
  15 #include <sound/pcm.h>
  16 #include <sound/pcm_params.h>
  17 #include "amdtp-stream.h"
  18
  19 #define TICKS_PER_CYCLE         3072
  20 #define CYCLES_PER_SECOND       8000
  21 #define TICKS_PER_SECOND        (TICKS_PER_CYCLE * CYCLES_PER_SECOND)
  22
  23 #define OHCI_MAX_SECOND         8
  24
  25 /* Always support Linux tracing subsystem. */
  26 #define CREATE_TRACE_POINTS
  27 #include "amdtp-stream-trace.h"
  28
  29 #define TRANSFER_DELAY_TICKS    0x2e00 /* 479.17 microseconds */
  30
  31 /* isochronous header parameters */
  32 #define ISO_DATA_LENGTH_SHIFT   16
  33 #define TAG_NO_CIP_HEADER       0
  34 #define TAG_CIP                 1
  35
  36 /* common isochronous packet header parameters */
  37 #define CIP_EOH_SHIFT           31
  38 #define CIP_EOH                 (1u << CIP_EOH_SHIFT)
  39 #define CIP_EOH_MASK            0x80000000
  40 #define CIP_SID_SHIFT           24
  41 #define CIP_SID_MASK            0x3f000000
  42 #define CIP_DBS_MASK            0x00ff0000
  43 #define CIP_DBS_SHIFT           16
  44 #define CIP_SPH_MASK            0x00000400
  45 #define CIP_SPH_SHIFT           10
  46 #define CIP_DBC_MASK            0x000000ff
  47 #define CIP_FMT_SHIFT           24
  48 #define CIP_FMT_MASK            0x3f000000
  49 #define CIP_FDF_MASK            0x00ff0000
  50 #define CIP_FDF_SHIFT           16
  51 #define CIP_SYT_MASK            0x0000ffff
  52 #define CIP_SYT_NO_INFO         0xffff
  53
  54 /* Audio and Music transfer protocol specific parameters */
  55 #define CIP_FMT_AM              0x10
  56 #define AMDTP_FDF_NO_DATA       0xff
  57
  58 // For iso header, tstamp and 2 CIP header.
  59 #define IR_CTX_HEADER_SIZE_CIP          16
  60 // For iso header and tstamp.
  61 #define IR_CTX_HEADER_SIZE_NO_CIP       8
  62 #define HEADER_TSTAMP_MASK      0x0000ffff
  63
  64 #define IT_PKT_HEADER_SIZE_CIP          8 // For 2 CIP header.
  65 #define IT_PKT_HEADER_SIZE_NO_CIP       0 // Nothing.
  66
  67 static void pcm_period_tasklet(struct tasklet_struct *t);
  68
  69 /**
  70  * amdtp_stream_init - initialize an AMDTP stream structure
  71  * @s: the AMDTP stream to initialize
  72  * @unit: the target of the stream
  73  * @dir: the direction of stream
  74  * @flags: the packet transmission method to use
  75  * @fmt: the value of fmt field in CIP header
  76  * @process_ctx_payloads: callback handler to process payloads of isoc context
  77  * @protocol_size: the size to allocate newly for protocol
  78  */
  79 int amdtp_stream_init(struct amdtp_stream *s, struct fw_unit *unit,
  80                       enum amdtp_stream_direction dir, enum cip_flags flags,
  81                       unsigned int fmt,
  82                       amdtp_stream_process_ctx_payloads_t process_ctx_payloads,
  83                       unsigned int protocol_size)
  84 {
  85         if (process_ctx_payloads == NULL)
  86                 return -EINVAL;
  87
  88         s->protocol = kzalloc(protocol_size, GFP_KERNEL);
  89         if (!s->protocol)
  90                 return -ENOMEM;
  91
  92         s->unit = unit;
  93         s->direction = dir;
  94         s->flags = flags;
  95         s->context = ERR_PTR(-1);
  96         mutex_init(&s->mutex);
  97         tasklet_setup(&s->period_tasklet, pcm_period_tasklet);
  98         s->packet_index = 0;
  99
 100         init_waitqueue_head(&s->callback_wait);
 101         s->callbacked = false;
 102
 103         s->fmt = fmt;
 104         s->process_ctx_payloads = process_ctx_payloads;
 105
 106         if (dir == AMDTP_OUT_STREAM)
 107                 s->ctx_data.rx.syt_override = -1;
 108
 109         return 0;
 110 }
 111 EXPORT_SYMBOL(amdtp_stream_init);
 112
 113 /**
 114  * amdtp_stream_destroy - free stream resources
 115  * @s: the AMDTP stream to destroy
 116  */
 117 void amdtp_stream_destroy(struct amdtp_stream *s)
 118 {
 119         /* Not initialized. */
 120         if (s->protocol == NULL)
 121                 return;
 122
 123         WARN_ON(amdtp_stream_running(s));
 124         kfree(s->protocol);
 125         mutex_destroy(&s->mutex);
 126 }
 127 EXPORT_SYMBOL(amdtp_stream_destroy);
 128
 129 const unsigned int amdtp_syt_intervals[CIP_SFC_COUNT] = {
 130         [CIP_SFC_32000]  =  8,
 131         [CIP_SFC_44100]  =  8,
 132         [CIP_SFC_48000]  =  8,
 133         [CIP_SFC_88200]  = 16,
 134         [CIP_SFC_96000]  = 16,
 135         [CIP_SFC_176400] = 32,
 136         [CIP_SFC_192000] = 32,
 137 };
 138 EXPORT_SYMBOL(amdtp_syt_intervals);
 139
 140 const unsigned int amdtp_rate_table[CIP_SFC_COUNT] = {
 141         [CIP_SFC_32000]  =  32000,
 142         [CIP_SFC_44100]  =  44100,
 143         [CIP_SFC_48000]  =  48000,
 144         [CIP_SFC_88200]  =  88200,
 145         [CIP_SFC_96000]  =  96000,
 146         [CIP_SFC_176400] = 176400,
 147         [CIP_SFC_192000] = 192000,
 148 };
 149 EXPORT_SYMBOL(amdtp_rate_table);
 150
 151 static int apply_constraint_to_size(struct snd_pcm_hw_params *params,
 152                                     struct snd_pcm_hw_rule *rule)
 153 {
 154         struct snd_interval *s = hw_param_interval(params, rule->var);
 155         const struct snd_interval *r =
 156                 hw_param_interval_c(params, SNDRV_PCM_HW_PARAM_RATE);
 157         struct snd_interval t = {0};
 158         unsigned int step = 0;
 159         int i;
 160
 161         for (i = 0; i < CIP_SFC_COUNT; ++i) {
 162                 if (snd_interval_test(r, amdtp_rate_table[i]))
 163                         step = max(step, amdtp_syt_intervals[i]);
 164         }
 165
 166         t.min = roundup(s->min, step);
 167         t.max = rounddown(s->max, step);
 168         t.integer = 1;
 169
 170         return snd_interval_refine(s, &t);
 171 }
 172
 173 /**
 174  * amdtp_stream_add_pcm_hw_constraints - add hw constraints for PCM substream
 175  * @s:          the AMDTP stream, which must be initialized.
 176  * @runtime:    the PCM substream runtime
 177  */
 178 int amdtp_stream_add_pcm_hw_constraints(struct amdtp_stream *s,
 179                                         struct snd_pcm_runtime *runtime)
 180 {
 181         struct snd_pcm_hardware *hw = &runtime->hw;
 182         unsigned int ctx_header_size;
 183         unsigned int maximum_usec_per_period;
 184         int err;
 185
 186         hw->info = SNDRV_PCM_INFO_BATCH |
 187                    SNDRV_PCM_INFO_BLOCK_TRANSFER |
 188                    SNDRV_PCM_INFO_INTERLEAVED |
 189                    SNDRV_PCM_INFO_JOINT_DUPLEX |
 190                    SNDRV_PCM_INFO_MMAP |
 191                    SNDRV_PCM_INFO_MMAP_VALID;
 192
 193         /* SNDRV_PCM_INFO_BATCH */
 194         hw->periods_min = 2;
 195         hw->periods_max = UINT_MAX;
 196
 197         /* bytes for a frame */
 198         hw->period_bytes_min = 4 * hw->channels_max;
 199
 200         /* Just to prevent from allocating much pages. */
 201         hw->period_bytes_max = hw->period_bytes_min * 2048;
 202         hw->buffer_bytes_max = hw->period_bytes_max * hw->periods_min;
 203
 204         // Linux driver for 1394 OHCI controller voluntarily flushes isoc
 205         // context when total size of accumulated context header reaches
 206         // PAGE_SIZE. This kicks tasklet for the isoc context and brings
 207         // callback in the middle of scheduled interrupts.
 208         // Although AMDTP streams in the same domain use the same events per
 209         // IRQ, use the largest size of context header between IT/IR contexts.
 210         // Here, use the value of context header in IR context is for both
 211         // contexts.
 212         if (!(s->flags & CIP_NO_HEADER))
 213                 ctx_header_size = IR_CTX_HEADER_SIZE_CIP;
 214         else
 215                 ctx_header_size = IR_CTX_HEADER_SIZE_NO_CIP;
 216         maximum_usec_per_period = USEC_PER_SEC * PAGE_SIZE /
 217                                   CYCLES_PER_SECOND / ctx_header_size;
 218
 219         // In IEC 61883-6, one isoc packet can transfer events up to the value
 220         // of syt interval. This comes from the interval of isoc cycle. As 1394
 221         // OHCI controller can generate hardware IRQ per isoc packet, the
 222         // interval is 125 usec.
 223         // However, there are two ways of transmission in IEC 61883-6; blocking
 224         // and non-blocking modes. In blocking mode, the sequence of isoc packet
 225         // includes 'empty' or 'NODATA' packets which include no event. In
 226         // non-blocking mode, the number of events per packet is variable up to
 227         // the syt interval.
 228         // Due to the above protocol design, the minimum PCM frames per
 229         // interrupt should be double of the value of syt interval, thus it is
 230         // 250 usec.
 231         err = snd_pcm_hw_constraint_minmax(runtime,
 232                                            SNDRV_PCM_HW_PARAM_PERIOD_TIME,
 233                                            250, maximum_usec_per_period);
 234         if (err < 0)
 235                 goto end;
 236
 237         /* Non-Blocking stream has no more constraints */
 238         if (!(s->flags & CIP_BLOCKING))
 239                 goto end;
 240
 241         /*
 242          * One AMDTP packet can include some frames. In blocking mode, the
 243          * number equals to SYT_INTERVAL. So the number is 8, 16 or 32,
 244          * depending on its sampling rate. For accurate period interrupt, it's
 245          * preferrable to align period/buffer sizes to current SYT_INTERVAL.
 246          */
 247         err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_SIZE,
 248                                   apply_constraint_to_size, NULL,
 249                                   SNDRV_PCM_HW_PARAM_PERIOD_SIZE,
 250                                   SNDRV_PCM_HW_PARAM_RATE, -1);
 251         if (err < 0)
 252                 goto end;
 253         err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_BUFFER_SIZE,
 254                                   apply_constraint_to_size, NULL,
 255                                   SNDRV_PCM_HW_PARAM_BUFFER_SIZE,
 256                                   SNDRV_PCM_HW_PARAM_RATE, -1);
 257         if (err < 0)
 258                 goto end;
 259 end:
 260         return err;
 261 }
 262 EXPORT_SYMBOL(amdtp_stream_add_pcm_hw_constraints);
 263
 264 /**
 265  * amdtp_stream_set_parameters - set stream parameters
 266  * @s: the AMDTP stream to configure
 267  * @rate: the sample rate
 268  * @data_block_quadlets: the size of a data block in quadlet unit
 269  *
 270  * The parameters must be set before the stream is started, and must not be
 271  * changed while the stream is running.
 272  */
 273 int amdtp_stream_set_parameters(struct amdtp_stream *s, unsigned int rate,
 274                                 unsigned int data_block_quadlets)
 275 {
 276         unsigned int sfc;
 277
 278         for (sfc = 0; sfc < ARRAY_SIZE(amdtp_rate_table); ++sfc) {
 279                 if (amdtp_rate_table[sfc] == rate)
 280                         break;
 281         }
 282         if (sfc == ARRAY_SIZE(amdtp_rate_table))
 283                 return -EINVAL;
 284
 285         s->sfc = sfc;
 286         s->data_block_quadlets = data_block_quadlets;
 287         s->syt_interval = amdtp_syt_intervals[sfc];
 288
 289         // default buffering in the device.
 290         if (s->direction == AMDTP_OUT_STREAM) {
 291                 s->ctx_data.rx.transfer_delay =
 292                                         TRANSFER_DELAY_TICKS - TICKS_PER_CYCLE;
 293
 294                 if (s->flags & CIP_BLOCKING) {
 295                         // additional buffering needed to adjust for no-data
 296                         // packets.
 297                         s->ctx_data.rx.transfer_delay +=
 298                                 TICKS_PER_SECOND * s->syt_interval / rate;
 299                 }
 300         }
 301
 302         return 0;
 303 }
 304 EXPORT_SYMBOL(amdtp_stream_set_parameters);
 305
 306 /**
 307  * amdtp_stream_get_max_payload - get the stream's packet size
 308  * @s: the AMDTP stream
 309  *
 310  * This function must not be called before the stream has been configured
 311  * with amdtp_stream_set_parameters().
 312  */
 313 unsigned int amdtp_stream_get_max_payload(struct amdtp_stream *s)
 314 {
 315         unsigned int multiplier = 1;
 316         unsigned int cip_header_size = 0;
 317
 318         if (s->flags & CIP_JUMBO_PAYLOAD)
 319                 multiplier = 5;
 320         if (!(s->flags & CIP_NO_HEADER))
 321                 cip_header_size = sizeof(__be32) * 2;
 322
 323         return cip_header_size +
 324                 s->syt_interval * s->data_block_quadlets * sizeof(__be32) * multiplier;
 325 }
 326 EXPORT_SYMBOL(amdtp_stream_get_max_payload);
 327
 328 /**
 329  * amdtp_stream_pcm_prepare - prepare PCM device for running
 330  * @s: the AMDTP stream
 331  *
 332  * This function should be called from the PCM device's .prepare callback.
 333  */
 334 void amdtp_stream_pcm_prepare(struct amdtp_stream *s)
 335 {
 336         tasklet_kill(&s->period_tasklet);
 337         s->pcm_buffer_pointer = 0;
 338         s->pcm_period_pointer = 0;
 339 }
 340 EXPORT_SYMBOL(amdtp_stream_pcm_prepare);
 341
 342 static unsigned int calculate_data_blocks(unsigned int *data_block_state,
 343                                 bool is_blocking, bool is_no_info,
 344                                 unsigned int syt_interval, enum cip_sfc sfc)
 345 {
 346         unsigned int data_blocks;
 347
 348         /* Blocking mode. */
 349         if (is_blocking) {
 350                 /* This module generate empty packet for 'no data'. */
 351                 if (is_no_info)
 352                         data_blocks = 0;
 353                 else
 354                         data_blocks = syt_interval;
 355         /* Non-blocking mode. */
 356         } else {
 357                 if (!cip_sfc_is_base_44100(sfc)) {
 358                         // Sample_rate / 8000 is an integer, and precomputed.
 359                         data_blocks = *data_block_state;
 360                 } else {
 361                         unsigned int phase = *data_block_state;
 362
 363                 /*
 364                  * This calculates the number of data blocks per packet so that
 365                  * 1) the overall rate is correct and exactly synchronized to
 366                  *    the bus clock, and
 367                  * 2) packets with a rounded-up number of blocks occur as early
 368                  *    as possible in the sequence (to prevent underruns of the
 369                  *    device's buffer).
 370                  */
 371                         if (sfc == CIP_SFC_44100)
 372                                 /* 6 6 5 6 5 6 5 ... */
 373                                 data_blocks = 5 + ((phase & 1) ^
 374                                                    (phase == 0 || phase >= 40));
 375                         else
 376                                 /* 12 11 11 11 11 ... or 23 22 22 22 22 ... */
 377                                 data_blocks = 11 * (sfc >> 1) + (phase == 0);
 378                         if (++phase >= (80 >> (sfc >> 1)))
 379                                 phase = 0;
 380                         *data_block_state = phase;
 381                 }
 382         }
 383
 384         return data_blocks;
 385 }
 386
 387 static unsigned int calculate_syt_offset(unsigned int *last_syt_offset,
 388                         unsigned int *syt_offset_state, enum cip_sfc sfc)
 389 {
 390         unsigned int syt_offset;
 391
 392         if (*last_syt_offset < TICKS_PER_CYCLE) {
 393                 if (!cip_sfc_is_base_44100(sfc))
 394                         syt_offset = *last_syt_offset + *syt_offset_state;
 395                 else {
 396                 /*
 397                  * The time, in ticks, of the n'th SYT_INTERVAL sample is:
 398                  *   n * SYT_INTERVAL * 24576000 / sample_rate
 399                  * Modulo TICKS_PER_CYCLE, the difference between successive
 400                  * elements is about 1386.23.  Rounding the results of this
 401                  * formula to the SYT precision results in a sequence of
 402                  * differences that begins with:
 403                  *   1386 1386 1387 1386 1386 1386 1387 1386 1386 1386 1387 ...
 404                  * This code generates _exactly_ the same sequence.
 405                  */
 406                         unsigned int phase = *syt_offset_state;
 407                         unsigned int index = phase % 13;
 408
 409                         syt_offset = *last_syt_offset;
 410                         syt_offset += 1386 + ((index && !(index & 3)) ||
 411                                               phase == 146);
 412                         if (++phase >= 147)
 413                                 phase = 0;
 414                         *syt_offset_state = phase;
 415                 }
 416         } else
 417                 syt_offset = *last_syt_offset - TICKS_PER_CYCLE;
 418         *last_syt_offset = syt_offset;
 419
 420         if (syt_offset >= TICKS_PER_CYCLE)
 421                 syt_offset = CIP_SYT_NO_INFO;
 422
 423         return syt_offset;
 424 }
 425
 426 static void update_pcm_pointers(struct amdtp_stream *s,
 427                                 struct snd_pcm_substream *pcm,
 428                                 unsigned int frames)
 429 {
 430         unsigned int ptr;
 431
 432         ptr = s->pcm_buffer_pointer + frames;
 433         if (ptr >= pcm->runtime->buffer_size)
 434                 ptr -= pcm->runtime->buffer_size;
 435         WRITE_ONCE(s->pcm_buffer_pointer, ptr);
 436
 437         s->pcm_period_pointer += frames;
 438         if (s->pcm_period_pointer >= pcm->runtime->period_size) {
 439                 s->pcm_period_pointer -= pcm->runtime->period_size;
 440                 tasklet_hi_schedule(&s->period_tasklet);
 441         }
 442 }
 443
 444 static void pcm_period_tasklet(struct tasklet_struct *t)
 445 {
 446         struct amdtp_stream *s = from_tasklet(s, t, period_tasklet);
 447         struct snd_pcm_substream *pcm = READ_ONCE(s->pcm);
 448
 449         if (pcm)
 450                 snd_pcm_period_elapsed(pcm);
 451 }
 452
 453 static int queue_packet(struct amdtp_stream *s, struct fw_iso_packet *params,
 454                         bool sched_irq)
 455 {
 456         int err;
 457
 458         params->interrupt = sched_irq;
 459         params->tag = s->tag;
 460         params->sy = 0;
 461
 462         err = fw_iso_context_queue(s->context, params, &s->buffer.iso_buffer,
 463                                    s->buffer.packets[s->packet_index].offset);
 464         if (err < 0) {
 465                 dev_err(&s->unit->device, "queueing error: %d\n", err);
 466                 goto end;
 467         }
 468
 469         if (++s->packet_index >= s->queue_size)
 470                 s->packet_index = 0;
 471 end:
 472         return err;
 473 }
 474
 475 static inline int queue_out_packet(struct amdtp_stream *s,
 476                                    struct fw_iso_packet *params, bool sched_irq)
 477 {
 478         params->skip =
 479                 !!(params->header_length == 0 && params->payload_length == 0);
 480         return queue_packet(s, params, sched_irq);
 481 }
 482
 483 static inline int queue_in_packet(struct amdtp_stream *s,
 484                                   struct fw_iso_packet *params)
 485 {
 486         // Queue one packet for IR context.
 487         params->header_length = s->ctx_data.tx.ctx_header_size;
 488         params->payload_length = s->ctx_data.tx.max_ctx_payload_length;
 489         params->skip = false;
 490         return queue_packet(s, params, false);
 491 }
 492
 493 static void generate_cip_header(struct amdtp_stream *s, __be32 cip_header[2],
 494                         unsigned int data_block_counter, unsigned int syt)
 495 {
 496         cip_header[0] = cpu_to_be32(READ_ONCE(s->source_node_id_field) |
 497                                 (s->data_block_quadlets << CIP_DBS_SHIFT) |
 498                                 ((s->sph << CIP_SPH_SHIFT) & CIP_SPH_MASK) |
 499                                 data_block_counter);
 500         cip_header[1] = cpu_to_be32(CIP_EOH |
 501                         ((s->fmt << CIP_FMT_SHIFT) & CIP_FMT_MASK) |
 502                         ((s->ctx_data.rx.fdf << CIP_FDF_SHIFT) & CIP_FDF_MASK) |
 503                         (syt & CIP_SYT_MASK));
 504 }
 505
 506 static void build_it_pkt_header(struct amdtp_stream *s, unsigned int cycle,
 507                                 struct fw_iso_packet *params,
 508                                 unsigned int data_blocks,
 509                                 unsigned int data_block_counter,
 510                                 unsigned int syt, unsigned int index)
 511 {
 512         unsigned int payload_length;
 513         __be32 *cip_header;
 514
 515         payload_length = data_blocks * sizeof(__be32) * s->data_block_quadlets;
 516         params->payload_length = payload_length;
 517
 518         if (!(s->flags & CIP_NO_HEADER)) {
 519                 cip_header = (__be32 *)params->header;
 520                 generate_cip_header(s, cip_header, data_block_counter, syt);
 521                 params->header_length = 2 * sizeof(__be32);
 522                 payload_length += params->header_length;
 523         } else {
 524                 cip_header = NULL;
 525         }
 526
 527         trace_amdtp_packet(s, cycle, cip_header, payload_length, data_blocks,
 528                            data_block_counter, index);
 529 }
 530
 531 static int check_cip_header(struct amdtp_stream *s, const __be32 *buf,
 532                             unsigned int payload_length,
 533                             unsigned int *data_blocks,
 534                             unsigned int *data_block_counter, unsigned int *syt)
 535 {
 536         u32 cip_header[2];
 537         unsigned int sph;
 538         unsigned int fmt;
 539         unsigned int fdf;
 540         unsigned int dbc;
 541         bool lost;
 542
 543         cip_header[0] = be32_to_cpu(buf[0]);
 544         cip_header[1] = be32_to_cpu(buf[1]);
 545
 546         /*
 547          * This module supports 'Two-quadlet CIP header with SYT field'.
 548          * For convenience, also check FMT field is AM824 or not.
 549          */
 550         if ((((cip_header[0] & CIP_EOH_MASK) == CIP_EOH) ||
 551              ((cip_header[1] & CIP_EOH_MASK) != CIP_EOH)) &&
 552             (!(s->flags & CIP_HEADER_WITHOUT_EOH))) {
 553                 dev_info_ratelimited(&s->unit->device,
 554                                 "Invalid CIP header for AMDTP: %08X:%08X\n",
 555                                 cip_header[0], cip_header[1]);
 556                 return -EAGAIN;
 557         }
 558
 559         /* Check valid protocol or not. */
 560         sph = (cip_header[0] & CIP_SPH_MASK) >> CIP_SPH_SHIFT;
 561         fmt = (cip_header[1] & CIP_FMT_MASK) >> CIP_FMT_SHIFT;
 562         if (sph != s->sph || fmt != s->fmt) {
 563                 dev_info_ratelimited(&s->unit->device,
 564                                      "Detect unexpected protocol: %08x %08x\n",
 565                                      cip_header[0], cip_header[1]);
 566                 return -EAGAIN;
 567         }
 568
 569         /* Calculate data blocks */
 570         fdf = (cip_header[1] & CIP_FDF_MASK) >> CIP_FDF_SHIFT;
 571         if (payload_length < sizeof(__be32) * 2 ||
 572             (fmt == CIP_FMT_AM && fdf == AMDTP_FDF_NO_DATA)) {
 573                 *data_blocks = 0;
 574         } else {
 575                 unsigned int data_block_quadlets =
 576                                 (cip_header[0] & CIP_DBS_MASK) >> CIP_DBS_SHIFT;
 577                 /* avoid division by zero */
 578                 if (data_block_quadlets == 0) {
 579                         dev_err(&s->unit->device,
 580                                 "Detect invalid value in dbs field: %08X\n",
 581                                 cip_header[0]);
 582                         return -EPROTO;
 583                 }
 584                 if (s->flags & CIP_WRONG_DBS)
 585                         data_block_quadlets = s->data_block_quadlets;
 586
 587                 *data_blocks = (payload_length / sizeof(__be32) - 2) /
 588                                                         data_block_quadlets;
 589         }
 590
 591         /* Check data block counter continuity */
 592         dbc = cip_header[0] & CIP_DBC_MASK;
 593         if (*data_blocks == 0 && (s->flags & CIP_EMPTY_HAS_WRONG_DBC) &&
 594             *data_block_counter != UINT_MAX)
 595                 dbc = *data_block_counter;
 596
 597         if ((dbc == 0x00 && (s->flags & CIP_SKIP_DBC_ZERO_CHECK)) ||
 598             *data_block_counter == UINT_MAX) {
 599                 lost = false;
 600         } else if (!(s->flags & CIP_DBC_IS_END_EVENT)) {
 601                 lost = dbc != *data_block_counter;
 602         } else {
 603                 unsigned int dbc_interval;
 604
 605                 if (*data_blocks > 0 && s->ctx_data.tx.dbc_interval > 0)
 606                         dbc_interval = s->ctx_data.tx.dbc_interval;
 607                 else
 608                         dbc_interval = *data_blocks;
 609
 610                 lost = dbc != ((*data_block_counter + dbc_interval) & 0xff);
 611         }
 612
 613         if (lost) {
 614                 dev_err(&s->unit->device,
 615                         "Detect discontinuity of CIP: %02X %02X\n",
 616                         *data_block_counter, dbc);
 617                 return -EIO;
 618         }
 619
 620         *data_block_counter = dbc;
 621
 622         *syt = cip_header[1] & CIP_SYT_MASK;
 623
 624         return 0;
 625 }
 626
 627 static int parse_ir_ctx_header(struct amdtp_stream *s, unsigned int cycle,
 628                                const __be32 *ctx_header,
 629                                unsigned int *payload_length,
 630                                unsigned int *data_blocks,
 631                                unsigned int *data_block_counter,
 632                                unsigned int *syt, unsigned int index)
 633 {
 634         const __be32 *cip_header;
 635         int err;
 636
 637         *payload_length = be32_to_cpu(ctx_header[0]) >> ISO_DATA_LENGTH_SHIFT;
 638         if (*payload_length > s->ctx_data.tx.ctx_header_size +
 639                                         s->ctx_data.tx.max_ctx_payload_length) {
 640                 dev_err(&s->unit->device,
 641                         "Detect jumbo payload: %04x %04x\n",
 642                         *payload_length, s->ctx_data.tx.max_ctx_payload_length);
 643                 return -EIO;
 644         }
 645
 646         if (!(s->flags & CIP_NO_HEADER)) {
 647                 cip_header = ctx_header + 2;
 648                 err = check_cip_header(s, cip_header, *payload_length,
 649                                        data_blocks, data_block_counter, syt);
 650                 if (err < 0)
 651                         return err;
 652         } else {
 653                 cip_header = NULL;
 654                 err = 0;
 655                 *data_blocks = *payload_length / sizeof(__be32) /
 656                                s->data_block_quadlets;
 657                 *syt = 0;
 658
 659                 if (*data_block_counter == UINT_MAX)
 660                         *data_block_counter = 0;
 661         }
 662
 663         trace_amdtp_packet(s, cycle, cip_header, *payload_length, *data_blocks,
 664                            *data_block_counter, index);
 665
 666         return err;
 667 }
 668
 669 // In CYCLE_TIMER register of IEEE 1394, 7 bits are used to represent second. On
 670 // the other hand, in DMA descriptors of 1394 OHCI, 3 bits are used to represent
 671 // it. Thus, via Linux firewire subsystem, we can get the 3 bits for second.
 672 static inline u32 compute_cycle_count(__be32 ctx_header_tstamp)
 673 {
 674         u32 tstamp = be32_to_cpu(ctx_header_tstamp) & HEADER_TSTAMP_MASK;
 675         return (((tstamp >> 13) & 0x07) * 8000) + (tstamp & 0x1fff);
 676 }
 677
 678 static inline u32 increment_cycle_count(u32 cycle, unsigned int addend)
 679 {
 680         cycle += addend;
 681         if (cycle >= OHCI_MAX_SECOND * CYCLES_PER_SECOND)
 682                 cycle -= OHCI_MAX_SECOND * CYCLES_PER_SECOND;
 683         return cycle;
 684 }
 685
 686 // Align to actual cycle count for the packet which is going to be scheduled.
 687 // This module queued the same number of isochronous cycle as the size of queue
 688 // to kip isochronous cycle, therefore it's OK to just increment the cycle by
 689 // the size of queue for scheduled cycle.
 690 static inline u32 compute_it_cycle(const __be32 ctx_header_tstamp,
 691                                    unsigned int queue_size)
 692 {
 693         u32 cycle = compute_cycle_count(ctx_header_tstamp);
 694         return increment_cycle_count(cycle, queue_size);
 695 }
 696
 697 static int generate_device_pkt_descs(struct amdtp_stream *s,
 698                                      struct pkt_desc *descs,
 699                                      const __be32 *ctx_header,
 700                                      unsigned int packets)
 701 {
 702         unsigned int dbc = s->data_block_counter;
 703         int i;
 704         int err;
 705
 706         for (i = 0; i < packets; ++i) {
 707                 struct pkt_desc *desc = descs + i;
 708                 unsigned int index = (s->packet_index + i) % s->queue_size;
 709                 unsigned int cycle;
 710                 unsigned int payload_length;
 711                 unsigned int data_blocks;
 712                 unsigned int syt;
 713
 714                 cycle = compute_cycle_count(ctx_header[1]);
 715
 716                 err = parse_ir_ctx_header(s, cycle, ctx_header, &payload_length,
 717                                           &data_blocks, &dbc, &syt, i);
 718                 if (err < 0)
 719                         return err;
 720
 721                 desc->cycle = cycle;
 722                 desc->syt = syt;
 723                 desc->data_blocks = data_blocks;
 724                 desc->data_block_counter = dbc;
 725                 desc->ctx_payload = s->buffer.packets[index].buffer;
 726
 727                 if (!(s->flags & CIP_DBC_IS_END_EVENT))
 728                         dbc = (dbc + desc->data_blocks) & 0xff;
 729
 730                 ctx_header +=
 731                         s->ctx_data.tx.ctx_header_size / sizeof(*ctx_header);
 732         }
 733
 734         s->data_block_counter = dbc;
 735
 736         return 0;
 737 }
 738
 739 static unsigned int compute_syt(unsigned int syt_offset, unsigned int cycle,
 740                                 unsigned int transfer_delay)
 741 {
 742         unsigned int syt;
 743
 744         syt_offset += transfer_delay;
 745         syt = ((cycle + syt_offset / TICKS_PER_CYCLE) << 12) |
 746               (syt_offset % TICKS_PER_CYCLE);
 747         return syt & CIP_SYT_MASK;
 748 }
 749
 750 static void generate_pkt_descs(struct amdtp_stream *s, struct pkt_desc *descs,
 751                                const __be32 *ctx_header, unsigned int packets,
 752                                const struct seq_desc *seq_descs,
 753                                unsigned int seq_size)
 754 {
 755         unsigned int dbc = s->data_block_counter;
 756         unsigned int seq_index = s->ctx_data.rx.seq_index;
 757         int i;
 758
 759         for (i = 0; i < packets; ++i) {
 760                 struct pkt_desc *desc = descs + i;
 761                 unsigned int index = (s->packet_index + i) % s->queue_size;
 762                 const struct seq_desc *seq = seq_descs + seq_index;
 763                 unsigned int syt;
 764
 765                 desc->cycle = compute_it_cycle(*ctx_header, s->queue_size);
 766
 767                 syt = seq->syt_offset;
 768                 if (syt != CIP_SYT_NO_INFO) {
 769                         syt = compute_syt(syt, desc->cycle,
 770                                           s->ctx_data.rx.transfer_delay);
 771                 }
 772                 desc->syt = syt;
 773                 desc->data_blocks = seq->data_blocks;
 774
 775                 if (s->flags & CIP_DBC_IS_END_EVENT)
 776                         dbc = (dbc + desc->data_blocks) & 0xff;
 777
 778                 desc->data_block_counter = dbc;
 779
 780                 if (!(s->flags & CIP_DBC_IS_END_EVENT))
 781                         dbc = (dbc + desc->data_blocks) & 0xff;
 782
 783                 desc->ctx_payload = s->buffer.packets[index].buffer;
 784
 785                 seq_index = (seq_index + 1) % seq_size;
 786
 787                 ++ctx_header;
 788         }
 789
 790         s->data_block_counter = dbc;
 791         s->ctx_data.rx.seq_index = seq_index;
 792 }
 793
 794 static inline void cancel_stream(struct amdtp_stream *s)
 795 {
 796         s->packet_index = -1;
 797         if (in_interrupt())
 798                 amdtp_stream_pcm_abort(s);
 799         WRITE_ONCE(s->pcm_buffer_pointer, SNDRV_PCM_POS_XRUN);
 800 }
 801
 802 static void process_ctx_payloads(struct amdtp_stream *s,
 803                                  const struct pkt_desc *descs,
 804                                  unsigned int packets)
 805 {
 806         struct snd_pcm_substream *pcm;
 807         unsigned int pcm_frames;
 808
 809         pcm = READ_ONCE(s->pcm);
 810         pcm_frames = s->process_ctx_payloads(s, descs, packets, pcm);
 811         if (pcm)
 812                 update_pcm_pointers(s, pcm, pcm_frames);
 813 }
 814
 815 static void out_stream_callback(struct fw_iso_context *context, u32 tstamp,
 816                                 size_t header_length, void *header,
 817                                 void *private_data)
 818 {
 819         struct amdtp_stream *s = private_data;
 820         const struct amdtp_domain *d = s->domain;
 821         const __be32 *ctx_header = header;
 822         unsigned int events_per_period = s->ctx_data.rx.events_per_period;
 823         unsigned int event_count = s->ctx_data.rx.event_count;
 824         unsigned int packets;
 825         int i;
 826
 827         if (s->packet_index < 0)
 828                 return;
 829
 830         // Calculate the number of packets in buffer and check XRUN.
 831         packets = header_length / sizeof(*ctx_header);
 832
 833         generate_pkt_descs(s, s->pkt_descs, ctx_header, packets, d->seq_descs,
 834                            d->seq_size);
 835
 836         process_ctx_payloads(s, s->pkt_descs, packets);
 837
 838         for (i = 0; i < packets; ++i) {
 839                 const struct pkt_desc *desc = s->pkt_descs + i;
 840                 unsigned int syt;
 841                 struct {
 842                         struct fw_iso_packet params;
 843                         __be32 header[IT_PKT_HEADER_SIZE_CIP / sizeof(__be32)];
 844                 } template = { {0}, {0} };
 845                 bool sched_irq = false;
 846
 847                 if (s->ctx_data.rx.syt_override < 0)
 848                         syt = desc->syt;
 849                 else
 850                         syt = s->ctx_data.rx.syt_override;
 851
 852                 build_it_pkt_header(s, desc->cycle, &template.params,
 853                                     desc->data_blocks, desc->data_block_counter,
 854                                     syt, i);
 855
 856                 if (s == s->domain->irq_target) {
 857                         event_count += desc->data_blocks;
 858                         if (event_count >= events_per_period) {
 859                                 event_count -= events_per_period;
 860                                 sched_irq = true;
 861                         }
 862                 }
 863
 864                 if (queue_out_packet(s, &template.params, sched_irq) < 0) {
 865                         cancel_stream(s);
 866                         return;
 867                 }
 868         }
 869
 870         s->ctx_data.rx.event_count = event_count;
 871 }
 872
 873 static void in_stream_callback(struct fw_iso_context *context, u32 tstamp,
 874                                size_t header_length, void *header,
 875                                void *private_data)
 876 {
 877         struct amdtp_stream *s = private_data;
 878         __be32 *ctx_header = header;
 879         unsigned int packets;
 880         int i;
 881         int err;
 882
 883         if (s->packet_index < 0)
 884                 return;
 885
 886         // Calculate the number of packets in buffer and check XRUN.
 887         packets = header_length / s->ctx_data.tx.ctx_header_size;
 888
 889         err = generate_device_pkt_descs(s, s->pkt_descs, ctx_header, packets);
 890         if (err < 0) {
 891                 if (err != -EAGAIN) {
 892                         cancel_stream(s);
 893                         return;
 894                 }
 895         } else {
 896                 process_ctx_payloads(s, s->pkt_descs, packets);
 897         }
 898
 899         for (i = 0; i < packets; ++i) {
 900                 struct fw_iso_packet params = {0};
 901
 902                 if (queue_in_packet(s, &params) < 0) {
 903                         cancel_stream(s);
 904                         return;
 905                 }
 906         }
 907 }
 908
 909 static void pool_ideal_seq_descs(struct amdtp_domain *d, unsigned int packets)
 910 {
 911         struct amdtp_stream *irq_target = d->irq_target;
 912         unsigned int seq_tail = d->seq_tail;
 913         unsigned int seq_size = d->seq_size;
 914         unsigned int min_avail;
 915         struct amdtp_stream *s;
 916
 917         min_avail = d->seq_size;
 918         list_for_each_entry(s, &d->streams, list) {
 919                 unsigned int seq_index;
 920                 unsigned int avail;
 921
 922                 if (s->direction == AMDTP_IN_STREAM)
 923                         continue;
 924
 925                 seq_index = s->ctx_data.rx.seq_index;
 926                 avail = d->seq_tail;
 927                 if (seq_index > avail)
 928                         avail += d->seq_size;
 929                 avail -= seq_index;
 930
 931                 if (avail < min_avail)
 932                         min_avail = avail;
 933         }
 934
 935         while (min_avail < packets) {
 936                 struct seq_desc *desc = d->seq_descs + seq_tail;
 937
 938                 desc->syt_offset = calculate_syt_offset(&d->last_syt_offset,
 939                                         &d->syt_offset_state, irq_target->sfc);
 940                 desc->data_blocks = calculate_data_blocks(&d->data_block_state,
 941                                 !!(irq_target->flags & CIP_BLOCKING),
 942                                 desc->syt_offset == CIP_SYT_NO_INFO,
 943                                 irq_target->syt_interval, irq_target->sfc);
 944
 945                 ++seq_tail;
 946                 seq_tail %= seq_size;
 947
 948                 ++min_avail;
 949         }
 950
 951         d->seq_tail = seq_tail;
 952 }
 953
 954 static void irq_target_callback(struct fw_iso_context *context, u32 tstamp,
 955                                 size_t header_length, void *header,
 956                                 void *private_data)
 957 {
 958         struct amdtp_stream *irq_target = private_data;
 959         struct amdtp_domain *d = irq_target->domain;
 960         unsigned int packets = header_length / sizeof(__be32);
 961         struct amdtp_stream *s;
 962
 963         // Record enough entries with extra 3 cycles at least.
 964         pool_ideal_seq_descs(d, packets + 3);
 965
 966         out_stream_callback(context, tstamp, header_length, header, irq_target);
 967         if (amdtp_streaming_error(irq_target))
 968                 goto error;
 969
 970         list_for_each_entry(s, &d->streams, list) {
 971                 if (s != irq_target && amdtp_stream_running(s)) {
 972                         fw_iso_context_flush_completions(s->context);
 973                         if (amdtp_streaming_error(s))
 974                                 goto error;
 975                 }
 976         }
 977
 978         return;
 979 error:
 980         if (amdtp_stream_running(irq_target))
 981                 cancel_stream(irq_target);
 982
 983         list_for_each_entry(s, &d->streams, list) {
 984                 if (amdtp_stream_running(s))
 985                         cancel_stream(s);
 986         }
 987 }
 988
 989 // this is executed one time.
 990 static void amdtp_stream_first_callback(struct fw_iso_context *context,
 991                                         u32 tstamp, size_t header_length,
 992                                         void *header, void *private_data)
 993 {
 994         struct amdtp_stream *s = private_data;
 995         const __be32 *ctx_header = header;
 996         u32 cycle;
 997
 998         /*
 999          * For in-stream, first packet has come.
1000          * For out-stream, prepared to transmit first packet
1001          */
1002         s->callbacked = true;
1003         wake_up(&s->callback_wait);
1004
1005         if (s->direction == AMDTP_IN_STREAM) {
1006                 cycle = compute_cycle_count(ctx_header[1]);
1007
1008                 context->callback.sc = in_stream_callback;
1009         } else {
1010                 cycle = compute_it_cycle(*ctx_header, s->queue_size);
1011
1012                 if (s == s->domain->irq_target)
1013                         context->callback.sc = irq_target_callback;
1014                 else
1015                         context->callback.sc = out_stream_callback;
1016         }
1017
1018         s->start_cycle = cycle;
1019
1020         context->callback.sc(context, tstamp, header_length, header, s);
1021 }
1022
1023 /**
1024  * amdtp_stream_start - start transferring packets
1025  * @s: the AMDTP stream to start
1026  * @channel: the isochronous channel on the bus
1027  * @speed: firewire speed code
1028  * @start_cycle: the isochronous cycle to start the context. Start immediately
1029  *               if negative value is given.
1030  * @queue_size: The number of packets in the queue.
1031  * @idle_irq_interval: the interval to queue packet during initial state.
1032  *
1033  * The stream cannot be started until it has been configured with
1034  * amdtp_stream_set_parameters() and it must be started before any PCM or MIDI
1035  * device can be started.
1036  */
1037 static int amdtp_stream_start(struct amdtp_stream *s, int channel, int speed,
1038                               int start_cycle, unsigned int queue_size,
1039                               unsigned int idle_irq_interval)
1040 {
1041         bool is_irq_target = (s == s->domain->irq_target);
1042         unsigned int ctx_header_size;
1043         unsigned int max_ctx_payload_size;
1044         enum dma_data_direction dir;
1045         int type, tag, err;
1046
1047         mutex_lock(&s->mutex);
1048
1049         if (WARN_ON(amdtp_stream_running(s) ||
1050                     (s->data_block_quadlets < 1))) {
1051                 err = -EBADFD;
1052                 goto err_unlock;
1053         }
1054
1055         if (s->direction == AMDTP_IN_STREAM) {
1056                 // NOTE: IT context should be used for constant IRQ.
1057                 if (is_irq_target) {
1058                         err = -EINVAL;
1059                         goto err_unlock;
1060                 }
1061
1062                 s->data_block_counter = UINT_MAX;
1063         } else {
1064                 s->data_block_counter = 0;
1065         }
1066
1067         /* initialize packet buffer */
1068         if (s->direction == AMDTP_IN_STREAM) {
1069                 dir = DMA_FROM_DEVICE;
1070                 type = FW_ISO_CONTEXT_RECEIVE;
1071                 if (!(s->flags & CIP_NO_HEADER))
1072                         ctx_header_size = IR_CTX_HEADER_SIZE_CIP;
1073                 else
1074                         ctx_header_size = IR_CTX_HEADER_SIZE_NO_CIP;
1075
1076                 max_ctx_payload_size = amdtp_stream_get_max_payload(s) -
1077                                        ctx_header_size;
1078         } else {
1079                 dir = DMA_TO_DEVICE;
1080                 type = FW_ISO_CONTEXT_TRANSMIT;
1081                 ctx_header_size = 0;    // No effect for IT context.
1082
1083                 max_ctx_payload_size = amdtp_stream_get_max_payload(s);
1084                 if (!(s->flags & CIP_NO_HEADER))
1085                         max_ctx_payload_size -= IT_PKT_HEADER_SIZE_CIP;
1086         }
1087
1088         err = iso_packets_buffer_init(&s->buffer, s->unit, queue_size,
1089                                       max_ctx_payload_size, dir);
1090         if (err < 0)
1091                 goto err_unlock;
1092         s->queue_size = queue_size;
1093
1094         s->context = fw_iso_context_create(fw_parent_device(s->unit)->card,
1095                                           type, channel, speed, ctx_header_size,
1096                                           amdtp_stream_first_callback, s);
1097         if (IS_ERR(s->context)) {
1098                 err = PTR_ERR(s->context);
1099                 if (err == -EBUSY)
1100                         dev_err(&s->unit->device,
1101                                 "no free stream on this controller\n");
1102                 goto err_buffer;
1103         }
1104
1105         amdtp_stream_update(s);
1106
1107         if (s->direction == AMDTP_IN_STREAM) {
1108                 s->ctx_data.tx.max_ctx_payload_length = max_ctx_payload_size;
1109                 s->ctx_data.tx.ctx_header_size = ctx_header_size;
1110         }
1111
1112         if (s->flags & CIP_NO_HEADER)
1113                 s->tag = TAG_NO_CIP_HEADER;
1114         else
1115                 s->tag = TAG_CIP;
1116
1117         s->pkt_descs = kcalloc(s->queue_size, sizeof(*s->pkt_descs),
1118                                GFP_KERNEL);
1119         if (!s->pkt_descs) {
1120                 err = -ENOMEM;
1121                 goto err_context;
1122         }
1123
1124         s->packet_index = 0;
1125         do {
1126                 struct fw_iso_packet params;
1127
1128                 if (s->direction == AMDTP_IN_STREAM) {
1129                         err = queue_in_packet(s, &params);
1130                 } else {
1131                         bool sched_irq = false;
1132
1133                         params.header_length = 0;
1134                         params.payload_length = 0;
1135
1136                         if (is_irq_target) {
1137                                 sched_irq = !((s->packet_index + 1) %
1138                                               idle_irq_interval);
1139                         }
1140
1141                         err = queue_out_packet(s, &params, sched_irq);
1142                 }
1143                 if (err < 0)
1144                         goto err_pkt_descs;
1145         } while (s->packet_index > 0);
1146
1147         /* NOTE: TAG1 matches CIP. This just affects in stream. */
1148         tag = FW_ISO_CONTEXT_MATCH_TAG1;
1149         if ((s->flags & CIP_EMPTY_WITH_TAG0) || (s->flags & CIP_NO_HEADER))
1150                 tag |= FW_ISO_CONTEXT_MATCH_TAG0;
1151
1152         s->callbacked = false;
1153         err = fw_iso_context_start(s->context, start_cycle, 0, tag);
1154         if (err < 0)
1155                 goto err_pkt_descs;
1156
1157         mutex_unlock(&s->mutex);
1158
1159         return 0;
1160 err_pkt_descs:
1161         kfree(s->pkt_descs);
1162 err_context:
1163         fw_iso_context_destroy(s->context);
1164         s->context = ERR_PTR(-1);
1165 err_buffer:
1166         iso_packets_buffer_destroy(&s->buffer, s->unit);
1167 err_unlock:
1168         mutex_unlock(&s->mutex);
1169
1170         return err;
1171 }
1172
1173 /**
1174  * amdtp_domain_stream_pcm_pointer - get the PCM buffer position
1175  * @d: the AMDTP domain.
1176  * @s: the AMDTP stream that transports the PCM data
1177  *
1178  * Returns the current buffer position, in frames.
1179  */
1180 unsigned long amdtp_domain_stream_pcm_pointer(struct amdtp_domain *d,
1181                                               struct amdtp_stream *s)
1182 {
1183         struct amdtp_stream *irq_target = d->irq_target;
1184
1185         if (irq_target && amdtp_stream_running(irq_target)) {
1186                 // This function is called in software IRQ context of
1187                 // period_tasklet or process context.
1188                 //
1189                 // When the software IRQ context was scheduled by software IRQ
1190                 // context of IT contexts, queued packets were already handled.
1191                 // Therefore, no need to flush the queue in buffer furthermore.
1192                 //
1193                 // When the process context reach here, some packets will be
1194                 // already queued in the buffer. These packets should be handled
1195                 // immediately to keep better granularity of PCM pointer.
1196                 //
1197                 // Later, the process context will sometimes schedules software
1198                 // IRQ context of the period_tasklet. Then, no need to flush the
1199                 // queue by the same reason as described in the above
1200                 if (!in_interrupt()) {
1201                         // Queued packet should be processed without any kernel
1202                         // preemption to keep latency against bus cycle.
1203                         preempt_disable();
1204                         fw_iso_context_flush_completions(irq_target->context);
1205                         preempt_enable();
1206                 }
1207         }
1208
1209         return READ_ONCE(s->pcm_buffer_pointer);
1210 }
1211 EXPORT_SYMBOL_GPL(amdtp_domain_stream_pcm_pointer);
1212
1213 /**
1214  * amdtp_domain_stream_pcm_ack - acknowledge queued PCM frames
1215  * @d: the AMDTP domain.
1216  * @s: the AMDTP stream that transfers the PCM frames
1217  *
1218  * Returns zero always.
1219  */
1220 int amdtp_domain_stream_pcm_ack(struct amdtp_domain *d, struct amdtp_stream *s)
1221 {
1222         struct amdtp_stream *irq_target = d->irq_target;
1223
1224         // Process isochronous packets for recent isochronous cycle to handle
1225         // queued PCM frames.
1226         if (irq_target && amdtp_stream_running(irq_target)) {
1227                 // Queued packet should be processed without any kernel
1228                 // preemption to keep latency against bus cycle.
1229                 preempt_disable();
1230                 fw_iso_context_flush_completions(irq_target->context);
1231                 preempt_enable();
1232         }
1233
1234         return 0;
1235 }
1236 EXPORT_SYMBOL_GPL(amdtp_domain_stream_pcm_ack);
1237
1238 /**
1239  * amdtp_stream_update - update the stream after a bus reset
1240  * @s: the AMDTP stream
1241  */
1242 void amdtp_stream_update(struct amdtp_stream *s)
1243 {
1244         /* Precomputing. */
1245         WRITE_ONCE(s->source_node_id_field,
1246                    (fw_parent_device(s->unit)->card->node_id << CIP_SID_SHIFT) & CIP_SID_MASK);
1247 }
1248 EXPORT_SYMBOL(amdtp_stream_update);
1249
1250 /**
1251  * amdtp_stream_stop - stop sending packets
1252  * @s: the AMDTP stream to stop
1253  *
1254  * All PCM and MIDI devices of the stream must be stopped before the stream
1255  * itself can be stopped.
1256  */
1257 static void amdtp_stream_stop(struct amdtp_stream *s)
1258 {
1259         mutex_lock(&s->mutex);
1260
1261         if (!amdtp_stream_running(s)) {
1262                 mutex_unlock(&s->mutex);
1263                 return;
1264         }
1265
1266         tasklet_kill(&s->period_tasklet);
1267         fw_iso_context_stop(s->context);
1268         fw_iso_context_destroy(s->context);
1269         s->context = ERR_PTR(-1);
1270         iso_packets_buffer_destroy(&s->buffer, s->unit);
1271         kfree(s->pkt_descs);
1272
1273         s->callbacked = false;
1274
1275         mutex_unlock(&s->mutex);
1276 }
1277
1278 /**
1279  * amdtp_stream_pcm_abort - abort the running PCM device
1280  * @s: the AMDTP stream about to be stopped
1281  *
1282  * If the isochronous stream needs to be stopped asynchronously, call this
1283  * function first to stop the PCM device.
1284  */
1285 void amdtp_stream_pcm_abort(struct amdtp_stream *s)
1286 {
1287         struct snd_pcm_substream *pcm;
1288
1289         pcm = READ_ONCE(s->pcm);
1290         if (pcm)
1291                 snd_pcm_stop_xrun(pcm);
1292 }
1293 EXPORT_SYMBOL(amdtp_stream_pcm_abort);
1294
1295 /**
1296  * amdtp_domain_init - initialize an AMDTP domain structure
1297  * @d: the AMDTP domain to initialize.
1298  */
1299 int amdtp_domain_init(struct amdtp_domain *d)
1300 {
1301         INIT_LIST_HEAD(&d->streams);
1302
1303         d->events_per_period = 0;
1304
1305         d->seq_descs = NULL;
1306
1307         return 0;
1308 }
1309 EXPORT_SYMBOL_GPL(amdtp_domain_init);
1310
1311 /**
1312  * amdtp_domain_destroy - destroy an AMDTP domain structure
1313  * @d: the AMDTP domain to destroy.
1314  */
1315 void amdtp_domain_destroy(struct amdtp_domain *d)
1316 {
1317         // At present nothing to do.
1318         return;
1319 }
1320 EXPORT_SYMBOL_GPL(amdtp_domain_destroy);
1321
1322 /**
1323  * amdtp_domain_add_stream - register isoc context into the domain.
1324  * @d: the AMDTP domain.
1325  * @s: the AMDTP stream.
1326  * @channel: the isochronous channel on the bus.
1327  * @speed: firewire speed code.
1328  */
1329 int amdtp_domain_add_stream(struct amdtp_domain *d, struct amdtp_stream *s,
1330                             int channel, int speed)
1331 {
1332         struct amdtp_stream *tmp;
1333
1334         list_for_each_entry(tmp, &d->streams, list) {
1335                 if (s == tmp)
1336                         return -EBUSY;
1337         }
1338
1339         list_add(&s->list, &d->streams);
1340
1341         s->channel = channel;
1342         s->speed = speed;
1343         s->domain = d;
1344
1345         return 0;
1346 }
1347 EXPORT_SYMBOL_GPL(amdtp_domain_add_stream);
1348
1349 static int get_current_cycle_time(struct fw_card *fw_card, int *cur_cycle)
1350 {
1351         int generation;
1352         int rcode;
1353         __be32 reg;
1354         u32 data;
1355
1356         // This is a request to local 1394 OHCI controller and expected to
1357         // complete without any event waiting.
1358         generation = fw_card->generation;
1359         smp_rmb();      // node_id vs. generation.
1360         rcode = fw_run_transaction(fw_card, TCODE_READ_QUADLET_REQUEST,
1361                                    fw_card->node_id, generation, SCODE_100,
1362                                    CSR_REGISTER_BASE + CSR_CYCLE_TIME,
1363                                    &reg, sizeof(reg));
1364         if (rcode != RCODE_COMPLETE)
1365                 return -EIO;
1366
1367         data = be32_to_cpu(reg);
1368         *cur_cycle = data >> 12;
1369
1370         return 0;
1371 }
1372
1373 /**
1374  * amdtp_domain_start - start sending packets for isoc context in the domain.
1375  * @d: the AMDTP domain.
1376  * @ir_delay_cycle: the cycle delay to start all IR contexts.
1377  */
1378 int amdtp_domain_start(struct amdtp_domain *d, unsigned int ir_delay_cycle)
1379 {
1380         static const struct {
1381                 unsigned int data_block;
1382                 unsigned int syt_offset;
1383         } *entry, initial_state[] = {
1384                 [CIP_SFC_32000]  = {  4, 3072 },
1385                 [CIP_SFC_48000]  = {  6, 1024 },
1386                 [CIP_SFC_96000]  = { 12, 1024 },
1387                 [CIP_SFC_192000] = { 24, 1024 },
1388                 [CIP_SFC_44100]  = {  0,   67 },
1389                 [CIP_SFC_88200]  = {  0,   67 },
1390                 [CIP_SFC_176400] = {  0,   67 },
1391         };
1392         unsigned int events_per_buffer = d->events_per_buffer;
1393         unsigned int events_per_period = d->events_per_period;
1394         unsigned int idle_irq_interval;
1395         unsigned int queue_size;
1396         struct amdtp_stream *s;
1397         int cycle;
1398         int err;
1399
1400         // Select an IT context as IRQ target.
1401         list_for_each_entry(s, &d->streams, list) {
1402                 if (s->direction == AMDTP_OUT_STREAM)
1403                         break;
1404         }
1405         if (!s)
1406                 return -ENXIO;
1407         d->irq_target = s;
1408
1409         // This is a case that AMDTP streams in domain run just for MIDI
1410         // substream. Use the number of events equivalent to 10 msec as
1411         // interval of hardware IRQ.
1412         if (events_per_period == 0)
1413                 events_per_period = amdtp_rate_table[d->irq_target->sfc] / 100;
1414         if (events_per_buffer == 0)
1415                 events_per_buffer = events_per_period * 3;
1416
1417         queue_size = DIV_ROUND_UP(CYCLES_PER_SECOND * events_per_buffer,
1418                                   amdtp_rate_table[d->irq_target->sfc]);
1419
1420         d->seq_descs = kcalloc(queue_size, sizeof(*d->seq_descs), GFP_KERNEL);
1421         if (!d->seq_descs)
1422                 return -ENOMEM;
1423         d->seq_size = queue_size;
1424         d->seq_tail = 0;
1425
1426         entry = &initial_state[s->sfc];
1427         d->data_block_state = entry->data_block;
1428         d->syt_offset_state = entry->syt_offset;
1429         d->last_syt_offset = TICKS_PER_CYCLE;
1430
1431         if (ir_delay_cycle > 0) {
1432                 struct fw_card *fw_card = fw_parent_device(s->unit)->card;
1433
1434                 err = get_current_cycle_time(fw_card, &cycle);
1435                 if (err < 0)
1436                         goto error;
1437
1438                 // No need to care overflow in cycle field because of enough
1439                 // width.
1440                 cycle += ir_delay_cycle;
1441
1442                 // Round up to sec field.
1443                 if ((cycle & 0x00001fff) >= CYCLES_PER_SECOND) {
1444                         unsigned int sec;
1445
1446                         // The sec field can overflow.
1447                         sec = (cycle & 0xffffe000) >> 13;
1448                         cycle = (++sec << 13) |
1449                                 ((cycle & 0x00001fff) / CYCLES_PER_SECOND);
1450                 }
1451
1452                 // In OHCI 1394 specification, lower 2 bits are available for
1453                 // sec field.
1454                 cycle &= 0x00007fff;
1455         } else {
1456                 cycle = -1;
1457         }
1458
1459         list_for_each_entry(s, &d->streams, list) {
1460                 int cycle_match;
1461
1462                 if (s->direction == AMDTP_IN_STREAM) {
1463                         cycle_match = cycle;
1464                 } else {
1465                         // IT context starts immediately.
1466                         cycle_match = -1;
1467                         s->ctx_data.rx.seq_index = 0;
1468                 }
1469
1470                 if (s != d->irq_target) {
1471                         err = amdtp_stream_start(s, s->channel, s->speed,
1472                                                  cycle_match, queue_size, 0);
1473                         if (err < 0)
1474                                 goto error;
1475                 }
1476         }
1477
1478         s = d->irq_target;
1479         s->ctx_data.rx.events_per_period = events_per_period;
1480         s->ctx_data.rx.event_count = 0;
1481         s->ctx_data.rx.seq_index = 0;
1482
1483         idle_irq_interval = DIV_ROUND_UP(CYCLES_PER_SECOND * events_per_period,
1484                                          amdtp_rate_table[d->irq_target->sfc]);
1485         err = amdtp_stream_start(s, s->channel, s->speed, -1, queue_size,
1486                                  idle_irq_interval);
1487         if (err < 0)
1488                 goto error;
1489
1490         return 0;
1491 error:
1492         list_for_each_entry(s, &d->streams, list)
1493                 amdtp_stream_stop(s);
1494         kfree(d->seq_descs);
1495         d->seq_descs = NULL;
1496         return err;
1497 }
1498 EXPORT_SYMBOL_GPL(amdtp_domain_start);
1499
1500 /**
1501  * amdtp_domain_stop - stop sending packets for isoc context in the same domain.
1502  * @d: the AMDTP domain to which the isoc contexts belong.
1503  */
1504 void amdtp_domain_stop(struct amdtp_domain *d)
1505 {
1506         struct amdtp_stream *s, *next;
1507
1508         if (d->irq_target)
1509                 amdtp_stream_stop(d->irq_target);
1510
1511         list_for_each_entry_safe(s, next, &d->streams, list) {
1512                 list_del(&s->list);
1513
1514                 if (s != d->irq_target)
1515                         amdtp_stream_stop(s);
1516         }
1517
1518         d->events_per_period = 0;
1519         d->irq_target = NULL;
1520
1521         kfree(d->seq_descs);
1522         d->seq_descs = NULL;
1523 }
1524 EXPORT_SYMBOL_GPL(amdtp_domain_stop);