sound/firewire/amdtp-stream.c

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This source file includes following definitions.
amdtp_stream_init
amdtp_stream_destroy
apply_constraint_to_size
amdtp_stream_add_pcm_hw_constraints
amdtp_stream_set_parameters
amdtp_stream_get_max_payload
amdtp_stream_pcm_prepare
calculate_data_blocks
calculate_syt
update_pcm_pointers
pcm_period_tasklet
queue_packet
queue_out_packet
queue_in_packet
generate_cip_header
build_it_pkt_header
check_cip_header
parse_ir_ctx_header
compute_cycle_count
increment_cycle_count
compute_it_cycle
generate_device_pkt_descs
generate_ideal_pkt_descs
cancel_stream
process_ctx_payloads
out_stream_callback
in_stream_callback
amdtp_stream_first_callback
amdtp_stream_start
amdtp_stream_pcm_pointer
amdtp_stream_pcm_ack
amdtp_stream_update
amdtp_stream_stop
amdtp_stream_pcm_abort
amdtp_domain_init
amdtp_domain_destroy
amdtp_domain_add_stream
amdtp_domain_start
amdtp_domain_stop
   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/module.h>
  13 #include <linux/slab.h>
  14 #include <sound/pcm.h>
  15 #include <sound/pcm_params.h>
  16 #include "amdtp-stream.h"
  17 
  18 #define TICKS_PER_CYCLE         3072
  19 #define CYCLES_PER_SECOND       8000
  20 #define TICKS_PER_SECOND        (TICKS_PER_CYCLE * CYCLES_PER_SECOND)
  21 
  22 /* Always support Linux tracing subsystem. */
  23 #define CREATE_TRACE_POINTS
  24 #include "amdtp-stream-trace.h"
  25 
  26 #define TRANSFER_DELAY_TICKS    0x2e00 /* 479.17 microseconds */
  27 
  28 /* isochronous header parameters */
  29 #define ISO_DATA_LENGTH_SHIFT   16
  30 #define TAG_NO_CIP_HEADER       0
  31 #define TAG_CIP                 1
  32 
  33 /* common isochronous packet header parameters */
  34 #define CIP_EOH_SHIFT           31
  35 #define CIP_EOH                 (1u << CIP_EOH_SHIFT)
  36 #define CIP_EOH_MASK            0x80000000
  37 #define CIP_SID_SHIFT           24
  38 #define CIP_SID_MASK            0x3f000000
  39 #define CIP_DBS_MASK            0x00ff0000
  40 #define CIP_DBS_SHIFT           16
  41 #define CIP_SPH_MASK            0x00000400
  42 #define CIP_SPH_SHIFT           10
  43 #define CIP_DBC_MASK            0x000000ff
  44 #define CIP_FMT_SHIFT           24
  45 #define CIP_FMT_MASK            0x3f000000
  46 #define CIP_FDF_MASK            0x00ff0000
  47 #define CIP_FDF_SHIFT           16
  48 #define CIP_SYT_MASK            0x0000ffff
  49 #define CIP_SYT_NO_INFO         0xffff
  50 
  51 /* Audio and Music transfer protocol specific parameters */
  52 #define CIP_FMT_AM              0x10
  53 #define AMDTP_FDF_NO_DATA       0xff
  54 
  55 /* TODO: make these configurable */
  56 #define INTERRUPT_INTERVAL      16
  57 #define QUEUE_LENGTH            48
  58 
  59 // For iso header, tstamp and 2 CIP header.
  60 #define IR_CTX_HEADER_SIZE_CIP          16
  61 // For iso header and tstamp.
  62 #define IR_CTX_HEADER_SIZE_NO_CIP       8
  63 #define HEADER_TSTAMP_MASK      0x0000ffff
  64 
  65 #define IT_PKT_HEADER_SIZE_CIP          8 // For 2 CIP header.
  66 #define IT_PKT_HEADER_SIZE_NO_CIP       0 // Nothing.
  67 
  68 static void pcm_period_tasklet(unsigned long data);
  69 
  70 /**
  71  * amdtp_stream_init - initialize an AMDTP stream structure
  72  * @s: the AMDTP stream to initialize
  73  * @unit: the target of the stream
  74  * @dir: the direction of stream
  75  * @flags: the packet transmission method to use
  76  * @fmt: the value of fmt field in CIP header
  77  * @process_ctx_payloads: callback handler to process payloads of isoc context
  78  * @protocol_size: the size to allocate newly for protocol
  79  */
  80 int amdtp_stream_init(struct amdtp_stream *s, struct fw_unit *unit,
  81                       enum amdtp_stream_direction dir, enum cip_flags flags,
  82                       unsigned int fmt,
  83                       amdtp_stream_process_ctx_payloads_t process_ctx_payloads,
  84                       unsigned int protocol_size)
  85 {
  86         if (process_ctx_payloads == NULL)
  87                 return -EINVAL;
  88 
  89         s->protocol = kzalloc(protocol_size, GFP_KERNEL);
  90         if (!s->protocol)
  91                 return -ENOMEM;
  92 
  93         s->unit = unit;
  94         s->direction = dir;
  95         s->flags = flags;
  96         s->context = ERR_PTR(-1);
  97         mutex_init(&s->mutex);
  98         tasklet_init(&s->period_tasklet, pcm_period_tasklet, (unsigned long)s);
  99         s->packet_index = 0;
 100 
 101         init_waitqueue_head(&s->callback_wait);
 102         s->callbacked = false;
 103 
 104         s->fmt = fmt;
 105         s->process_ctx_payloads = process_ctx_payloads;
 106 
 107         if (dir == AMDTP_OUT_STREAM)
 108                 s->ctx_data.rx.syt_override = -1;
 109 
 110         return 0;
 111 }
 112 EXPORT_SYMBOL(amdtp_stream_init);
 113 
 114 /**
 115  * amdtp_stream_destroy - free stream resources
 116  * @s: the AMDTP stream to destroy
 117  */
 118 void amdtp_stream_destroy(struct amdtp_stream *s)
 119 {
 120         /* Not initialized. */
 121         if (s->protocol == NULL)
 122                 return;
 123 
 124         WARN_ON(amdtp_stream_running(s));
 125         kfree(s->protocol);
 126         mutex_destroy(&s->mutex);
 127 }
 128 EXPORT_SYMBOL(amdtp_stream_destroy);
 129 
 130 const unsigned int amdtp_syt_intervals[CIP_SFC_COUNT] = {
 131         [CIP_SFC_32000]  =  8,
 132         [CIP_SFC_44100]  =  8,
 133         [CIP_SFC_48000]  =  8,
 134         [CIP_SFC_88200]  = 16,
 135         [CIP_SFC_96000]  = 16,
 136         [CIP_SFC_176400] = 32,
 137         [CIP_SFC_192000] = 32,
 138 };
 139 EXPORT_SYMBOL(amdtp_syt_intervals);
 140 
 141 const unsigned int amdtp_rate_table[CIP_SFC_COUNT] = {
 142         [CIP_SFC_32000]  =  32000,
 143         [CIP_SFC_44100]  =  44100,
 144         [CIP_SFC_48000]  =  48000,
 145         [CIP_SFC_88200]  =  88200,
 146         [CIP_SFC_96000]  =  96000,
 147         [CIP_SFC_176400] = 176400,
 148         [CIP_SFC_192000] = 192000,
 149 };
 150 EXPORT_SYMBOL(amdtp_rate_table);
 151 
 152 static int apply_constraint_to_size(struct snd_pcm_hw_params *params,
 153                                     struct snd_pcm_hw_rule *rule)
 154 {
 155         struct snd_interval *s = hw_param_interval(params, rule->var);
 156         const struct snd_interval *r =
 157                 hw_param_interval_c(params, SNDRV_PCM_HW_PARAM_RATE);
 158         struct snd_interval t = {0};
 159         unsigned int step = 0;
 160         int i;
 161 
 162         for (i = 0; i < CIP_SFC_COUNT; ++i) {
 163                 if (snd_interval_test(r, amdtp_rate_table[i]))
 164                         step = max(step, amdtp_syt_intervals[i]);
 165         }
 166 
 167         t.min = roundup(s->min, step);
 168         t.max = rounddown(s->max, step);
 169         t.integer = 1;
 170 
 171         return snd_interval_refine(s, &t);
 172 }
 173 
 174 /**
 175  * amdtp_stream_add_pcm_hw_constraints - add hw constraints for PCM substream
 176  * @s:          the AMDTP stream, which must be initialized.
 177  * @runtime:    the PCM substream runtime
 178  */
 179 int amdtp_stream_add_pcm_hw_constraints(struct amdtp_stream *s,
 180                                         struct snd_pcm_runtime *runtime)
 181 {
 182         struct snd_pcm_hardware *hw = &runtime->hw;
 183         int err;
 184 
 185         hw->info = SNDRV_PCM_INFO_BATCH |
 186                    SNDRV_PCM_INFO_BLOCK_TRANSFER |
 187                    SNDRV_PCM_INFO_INTERLEAVED |
 188                    SNDRV_PCM_INFO_JOINT_DUPLEX |
 189                    SNDRV_PCM_INFO_MMAP |
 190                    SNDRV_PCM_INFO_MMAP_VALID;
 191 
 192         /* SNDRV_PCM_INFO_BATCH */
 193         hw->periods_min = 2;
 194         hw->periods_max = UINT_MAX;
 195 
 196         /* bytes for a frame */
 197         hw->period_bytes_min = 4 * hw->channels_max;
 198 
 199         /* Just to prevent from allocating much pages. */
 200         hw->period_bytes_max = hw->period_bytes_min * 2048;
 201         hw->buffer_bytes_max = hw->period_bytes_max * hw->periods_min;
 202 
 203         /*
 204          * Currently firewire-lib processes 16 packets in one software
 205          * interrupt callback. This equals to 2msec but actually the
 206          * interval of the interrupts has a jitter.
 207          * Additionally, even if adding a constraint to fit period size to
 208          * 2msec, actual calculated frames per period doesn't equal to 2msec,
 209          * depending on sampling rate.
 210          * Anyway, the interval to call snd_pcm_period_elapsed() cannot 2msec.
 211          * Here let us use 5msec for safe period interrupt.
 212          */
 213         err = snd_pcm_hw_constraint_minmax(runtime,
 214                                            SNDRV_PCM_HW_PARAM_PERIOD_TIME,
 215                                            5000, UINT_MAX);
 216         if (err < 0)
 217                 goto end;
 218 
 219         /* Non-Blocking stream has no more constraints */
 220         if (!(s->flags & CIP_BLOCKING))
 221                 goto end;
 222 
 223         /*
 224          * One AMDTP packet can include some frames. In blocking mode, the
 225          * number equals to SYT_INTERVAL. So the number is 8, 16 or 32,
 226          * depending on its sampling rate. For accurate period interrupt, it's
 227          * preferrable to align period/buffer sizes to current SYT_INTERVAL.
 228          */
 229         err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_SIZE,
 230                                   apply_constraint_to_size, NULL,
 231                                   SNDRV_PCM_HW_PARAM_PERIOD_SIZE,
 232                                   SNDRV_PCM_HW_PARAM_RATE, -1);
 233         if (err < 0)
 234                 goto end;
 235         err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_BUFFER_SIZE,
 236                                   apply_constraint_to_size, NULL,
 237                                   SNDRV_PCM_HW_PARAM_BUFFER_SIZE,
 238                                   SNDRV_PCM_HW_PARAM_RATE, -1);
 239         if (err < 0)
 240                 goto end;
 241 end:
 242         return err;
 243 }
 244 EXPORT_SYMBOL(amdtp_stream_add_pcm_hw_constraints);
 245 
 246 /**
 247  * amdtp_stream_set_parameters - set stream parameters
 248  * @s: the AMDTP stream to configure
 249  * @rate: the sample rate
 250  * @data_block_quadlets: the size of a data block in quadlet unit
 251  *
 252  * The parameters must be set before the stream is started, and must not be
 253  * changed while the stream is running.
 254  */
 255 int amdtp_stream_set_parameters(struct amdtp_stream *s, unsigned int rate,
 256                                 unsigned int data_block_quadlets)
 257 {
 258         unsigned int sfc;
 259 
 260         for (sfc = 0; sfc < ARRAY_SIZE(amdtp_rate_table); ++sfc) {
 261                 if (amdtp_rate_table[sfc] == rate)
 262                         break;
 263         }
 264         if (sfc == ARRAY_SIZE(amdtp_rate_table))
 265                 return -EINVAL;
 266 
 267         s->sfc = sfc;
 268         s->data_block_quadlets = data_block_quadlets;
 269         s->syt_interval = amdtp_syt_intervals[sfc];
 270 
 271         // default buffering in the device.
 272         if (s->direction == AMDTP_OUT_STREAM) {
 273                 s->ctx_data.rx.transfer_delay =
 274                                         TRANSFER_DELAY_TICKS - TICKS_PER_CYCLE;
 275 
 276                 if (s->flags & CIP_BLOCKING) {
 277                         // additional buffering needed to adjust for no-data
 278                         // packets.
 279                         s->ctx_data.rx.transfer_delay +=
 280                                 TICKS_PER_SECOND * s->syt_interval / rate;
 281                 }
 282         }
 283 
 284         return 0;
 285 }
 286 EXPORT_SYMBOL(amdtp_stream_set_parameters);
 287 
 288 /**
 289  * amdtp_stream_get_max_payload - get the stream's packet size
 290  * @s: the AMDTP stream
 291  *
 292  * This function must not be called before the stream has been configured
 293  * with amdtp_stream_set_parameters().
 294  */
 295 unsigned int amdtp_stream_get_max_payload(struct amdtp_stream *s)
 296 {
 297         unsigned int multiplier = 1;
 298         unsigned int cip_header_size = 0;
 299 
 300         if (s->flags & CIP_JUMBO_PAYLOAD)
 301                 multiplier = 5;
 302         if (!(s->flags & CIP_NO_HEADER))
 303                 cip_header_size = sizeof(__be32) * 2;
 304 
 305         return cip_header_size +
 306                 s->syt_interval * s->data_block_quadlets * sizeof(__be32) * multiplier;
 307 }
 308 EXPORT_SYMBOL(amdtp_stream_get_max_payload);
 309 
 310 /**
 311  * amdtp_stream_pcm_prepare - prepare PCM device for running
 312  * @s: the AMDTP stream
 313  *
 314  * This function should be called from the PCM device's .prepare callback.
 315  */
 316 void amdtp_stream_pcm_prepare(struct amdtp_stream *s)
 317 {
 318         tasklet_kill(&s->period_tasklet);
 319         s->pcm_buffer_pointer = 0;
 320         s->pcm_period_pointer = 0;
 321 }
 322 EXPORT_SYMBOL(amdtp_stream_pcm_prepare);
 323 
 324 static unsigned int calculate_data_blocks(struct amdtp_stream *s,
 325                                           unsigned int syt)
 326 {
 327         unsigned int phase, data_blocks;
 328 
 329         /* Blocking mode. */
 330         if (s->flags & CIP_BLOCKING) {
 331                 /* This module generate empty packet for 'no data'. */
 332                 if (syt == CIP_SYT_NO_INFO)
 333                         data_blocks = 0;
 334                 else
 335                         data_blocks = s->syt_interval;
 336         /* Non-blocking mode. */
 337         } else {
 338                 if (!cip_sfc_is_base_44100(s->sfc)) {
 339                         // Sample_rate / 8000 is an integer, and precomputed.
 340                         data_blocks = s->ctx_data.rx.data_block_state;
 341                 } else {
 342                         phase = s->ctx_data.rx.data_block_state;
 343 
 344                 /*
 345                  * This calculates the number of data blocks per packet so that
 346                  * 1) the overall rate is correct and exactly synchronized to
 347                  *    the bus clock, and
 348                  * 2) packets with a rounded-up number of blocks occur as early
 349                  *    as possible in the sequence (to prevent underruns of the
 350                  *    device's buffer).
 351                  */
 352                         if (s->sfc == CIP_SFC_44100)
 353                                 /* 6 6 5 6 5 6 5 ... */
 354                                 data_blocks = 5 + ((phase & 1) ^
 355                                                    (phase == 0 || phase >= 40));
 356                         else
 357                                 /* 12 11 11 11 11 ... or 23 22 22 22 22 ... */
 358                                 data_blocks = 11 * (s->sfc >> 1) + (phase == 0);
 359                         if (++phase >= (80 >> (s->sfc >> 1)))
 360                                 phase = 0;
 361                         s->ctx_data.rx.data_block_state = phase;
 362                 }
 363         }
 364 
 365         return data_blocks;
 366 }
 367 
 368 static unsigned int calculate_syt(struct amdtp_stream *s,
 369                                   unsigned int cycle)
 370 {
 371         unsigned int syt_offset, phase, index, syt;
 372 
 373         if (s->ctx_data.rx.last_syt_offset < TICKS_PER_CYCLE) {
 374                 if (!cip_sfc_is_base_44100(s->sfc))
 375                         syt_offset = s->ctx_data.rx.last_syt_offset +
 376                                      s->ctx_data.rx.syt_offset_state;
 377                 else {
 378                 /*
 379                  * The time, in ticks, of the n'th SYT_INTERVAL sample is:
 380                  *   n * SYT_INTERVAL * 24576000 / sample_rate
 381                  * Modulo TICKS_PER_CYCLE, the difference between successive
 382                  * elements is about 1386.23.  Rounding the results of this
 383                  * formula to the SYT precision results in a sequence of
 384                  * differences that begins with:
 385                  *   1386 1386 1387 1386 1386 1386 1387 1386 1386 1386 1387 ...
 386                  * This code generates _exactly_ the same sequence.
 387                  */
 388                         phase = s->ctx_data.rx.syt_offset_state;
 389                         index = phase % 13;
 390                         syt_offset = s->ctx_data.rx.last_syt_offset;
 391                         syt_offset += 1386 + ((index && !(index & 3)) ||
 392                                               phase == 146);
 393                         if (++phase >= 147)
 394                                 phase = 0;
 395                         s->ctx_data.rx.syt_offset_state = phase;
 396                 }
 397         } else
 398                 syt_offset = s->ctx_data.rx.last_syt_offset - TICKS_PER_CYCLE;
 399         s->ctx_data.rx.last_syt_offset = syt_offset;
 400 
 401         if (syt_offset < TICKS_PER_CYCLE) {
 402                 syt_offset += s->ctx_data.rx.transfer_delay;
 403                 syt = (cycle + syt_offset / TICKS_PER_CYCLE) << 12;
 404                 syt += syt_offset % TICKS_PER_CYCLE;
 405 
 406                 return syt & CIP_SYT_MASK;
 407         } else {
 408                 return CIP_SYT_NO_INFO;
 409         }
 410 }
 411 
 412 static void update_pcm_pointers(struct amdtp_stream *s,
 413                                 struct snd_pcm_substream *pcm,
 414                                 unsigned int frames)
 415 {
 416         unsigned int ptr;
 417 
 418         ptr = s->pcm_buffer_pointer + frames;
 419         if (ptr >= pcm->runtime->buffer_size)
 420                 ptr -= pcm->runtime->buffer_size;
 421         WRITE_ONCE(s->pcm_buffer_pointer, ptr);
 422 
 423         s->pcm_period_pointer += frames;
 424         if (s->pcm_period_pointer >= pcm->runtime->period_size) {
 425                 s->pcm_period_pointer -= pcm->runtime->period_size;
 426                 tasklet_hi_schedule(&s->period_tasklet);
 427         }
 428 }
 429 
 430 static void pcm_period_tasklet(unsigned long data)
 431 {
 432         struct amdtp_stream *s = (void *)data;
 433         struct snd_pcm_substream *pcm = READ_ONCE(s->pcm);
 434 
 435         if (pcm)
 436                 snd_pcm_period_elapsed(pcm);
 437 }
 438 
 439 static int queue_packet(struct amdtp_stream *s, struct fw_iso_packet *params)
 440 {
 441         int err;
 442 
 443         params->interrupt = IS_ALIGNED(s->packet_index + 1, INTERRUPT_INTERVAL);
 444         params->tag = s->tag;
 445         params->sy = 0;
 446 
 447         err = fw_iso_context_queue(s->context, params, &s->buffer.iso_buffer,
 448                                    s->buffer.packets[s->packet_index].offset);
 449         if (err < 0) {
 450                 dev_err(&s->unit->device, "queueing error: %d\n", err);
 451                 goto end;
 452         }
 453 
 454         if (++s->packet_index >= QUEUE_LENGTH)
 455                 s->packet_index = 0;
 456 end:
 457         return err;
 458 }
 459 
 460 static inline int queue_out_packet(struct amdtp_stream *s,
 461                                    struct fw_iso_packet *params)
 462 {
 463         params->skip =
 464                 !!(params->header_length == 0 && params->payload_length == 0);
 465         return queue_packet(s, params);
 466 }
 467 
 468 static inline int queue_in_packet(struct amdtp_stream *s,
 469                                   struct fw_iso_packet *params)
 470 {
 471         // Queue one packet for IR context.
 472         params->header_length = s->ctx_data.tx.ctx_header_size;
 473         params->payload_length = s->ctx_data.tx.max_ctx_payload_length;
 474         params->skip = false;
 475         return queue_packet(s, params);
 476 }
 477 
 478 static void generate_cip_header(struct amdtp_stream *s, __be32 cip_header[2],
 479                         unsigned int data_block_counter, unsigned int syt)
 480 {
 481         cip_header[0] = cpu_to_be32(READ_ONCE(s->source_node_id_field) |
 482                                 (s->data_block_quadlets << CIP_DBS_SHIFT) |
 483                                 ((s->sph << CIP_SPH_SHIFT) & CIP_SPH_MASK) |
 484                                 data_block_counter);
 485         cip_header[1] = cpu_to_be32(CIP_EOH |
 486                         ((s->fmt << CIP_FMT_SHIFT) & CIP_FMT_MASK) |
 487                         ((s->ctx_data.rx.fdf << CIP_FDF_SHIFT) & CIP_FDF_MASK) |
 488                         (syt & CIP_SYT_MASK));
 489 }
 490 
 491 static void build_it_pkt_header(struct amdtp_stream *s, unsigned int cycle,
 492                                 struct fw_iso_packet *params,
 493                                 unsigned int data_blocks,
 494                                 unsigned int data_block_counter,
 495                                 unsigned int syt, unsigned int index)
 496 {
 497         unsigned int payload_length;
 498         __be32 *cip_header;
 499 
 500         payload_length = data_blocks * sizeof(__be32) * s->data_block_quadlets;
 501         params->payload_length = payload_length;
 502 
 503         if (!(s->flags & CIP_NO_HEADER)) {
 504                 cip_header = (__be32 *)params->header;
 505                 generate_cip_header(s, cip_header, data_block_counter, syt);
 506                 params->header_length = 2 * sizeof(__be32);
 507                 payload_length += params->header_length;
 508         } else {
 509                 cip_header = NULL;
 510         }
 511 
 512         trace_amdtp_packet(s, cycle, cip_header, payload_length, data_blocks,
 513                            data_block_counter, index);
 514 }
 515 
 516 static int check_cip_header(struct amdtp_stream *s, const __be32 *buf,
 517                             unsigned int payload_length,
 518                             unsigned int *data_blocks,
 519                             unsigned int *data_block_counter, unsigned int *syt)
 520 {
 521         u32 cip_header[2];
 522         unsigned int sph;
 523         unsigned int fmt;
 524         unsigned int fdf;
 525         unsigned int dbc;
 526         bool lost;
 527 
 528         cip_header[0] = be32_to_cpu(buf[0]);
 529         cip_header[1] = be32_to_cpu(buf[1]);
 530 
 531         /*
 532          * This module supports 'Two-quadlet CIP header with SYT field'.
 533          * For convenience, also check FMT field is AM824 or not.
 534          */
 535         if ((((cip_header[0] & CIP_EOH_MASK) == CIP_EOH) ||
 536              ((cip_header[1] & CIP_EOH_MASK) != CIP_EOH)) &&
 537             (!(s->flags & CIP_HEADER_WITHOUT_EOH))) {
 538                 dev_info_ratelimited(&s->unit->device,
 539                                 "Invalid CIP header for AMDTP: %08X:%08X\n",
 540                                 cip_header[0], cip_header[1]);
 541                 return -EAGAIN;
 542         }
 543 
 544         /* Check valid protocol or not. */
 545         sph = (cip_header[0] & CIP_SPH_MASK) >> CIP_SPH_SHIFT;
 546         fmt = (cip_header[1] & CIP_FMT_MASK) >> CIP_FMT_SHIFT;
 547         if (sph != s->sph || fmt != s->fmt) {
 548                 dev_info_ratelimited(&s->unit->device,
 549                                      "Detect unexpected protocol: %08x %08x\n",
 550                                      cip_header[0], cip_header[1]);
 551                 return -EAGAIN;
 552         }
 553 
 554         /* Calculate data blocks */
 555         fdf = (cip_header[1] & CIP_FDF_MASK) >> CIP_FDF_SHIFT;
 556         if (payload_length < sizeof(__be32) * 2 ||
 557             (fmt == CIP_FMT_AM && fdf == AMDTP_FDF_NO_DATA)) {
 558                 *data_blocks = 0;
 559         } else {
 560                 unsigned int data_block_quadlets =
 561                                 (cip_header[0] & CIP_DBS_MASK) >> CIP_DBS_SHIFT;
 562                 /* avoid division by zero */
 563                 if (data_block_quadlets == 0) {
 564                         dev_err(&s->unit->device,
 565                                 "Detect invalid value in dbs field: %08X\n",
 566                                 cip_header[0]);
 567                         return -EPROTO;
 568                 }
 569                 if (s->flags & CIP_WRONG_DBS)
 570                         data_block_quadlets = s->data_block_quadlets;
 571 
 572                 *data_blocks = (payload_length / sizeof(__be32) - 2) /
 573                                                         data_block_quadlets;
 574         }
 575 
 576         /* Check data block counter continuity */
 577         dbc = cip_header[0] & CIP_DBC_MASK;
 578         if (*data_blocks == 0 && (s->flags & CIP_EMPTY_HAS_WRONG_DBC) &&
 579             *data_block_counter != UINT_MAX)
 580                 dbc = *data_block_counter;
 581 
 582         if ((dbc == 0x00 && (s->flags & CIP_SKIP_DBC_ZERO_CHECK)) ||
 583             *data_block_counter == UINT_MAX) {
 584                 lost = false;
 585         } else if (!(s->flags & CIP_DBC_IS_END_EVENT)) {
 586                 lost = dbc != *data_block_counter;
 587         } else {
 588                 unsigned int dbc_interval;
 589 
 590                 if (*data_blocks > 0 && s->ctx_data.tx.dbc_interval > 0)
 591                         dbc_interval = s->ctx_data.tx.dbc_interval;
 592                 else
 593                         dbc_interval = *data_blocks;
 594 
 595                 lost = dbc != ((*data_block_counter + dbc_interval) & 0xff);
 596         }
 597 
 598         if (lost) {
 599                 dev_err(&s->unit->device,
 600                         "Detect discontinuity of CIP: %02X %02X\n",
 601                         *data_block_counter, dbc);
 602                 return -EIO;
 603         }
 604 
 605         *data_block_counter = dbc;
 606 
 607         *syt = cip_header[1] & CIP_SYT_MASK;
 608 
 609         return 0;
 610 }
 611 
 612 static int parse_ir_ctx_header(struct amdtp_stream *s, unsigned int cycle,
 613                                const __be32 *ctx_header,
 614                                unsigned int *payload_length,
 615                                unsigned int *data_blocks,
 616                                unsigned int *data_block_counter,
 617                                unsigned int *syt, unsigned int index)
 618 {
 619         const __be32 *cip_header;
 620         int err;
 621 
 622         *payload_length = be32_to_cpu(ctx_header[0]) >> ISO_DATA_LENGTH_SHIFT;
 623         if (*payload_length > s->ctx_data.tx.ctx_header_size +
 624                                         s->ctx_data.tx.max_ctx_payload_length) {
 625                 dev_err(&s->unit->device,
 626                         "Detect jumbo payload: %04x %04x\n",
 627                         *payload_length, s->ctx_data.tx.max_ctx_payload_length);
 628                 return -EIO;
 629         }
 630 
 631         if (!(s->flags & CIP_NO_HEADER)) {
 632                 cip_header = ctx_header + 2;
 633                 err = check_cip_header(s, cip_header, *payload_length,
 634                                        data_blocks, data_block_counter, syt);
 635                 if (err < 0)
 636                         return err;
 637         } else {
 638                 cip_header = NULL;
 639                 err = 0;
 640                 *data_blocks = *payload_length / sizeof(__be32) /
 641                                s->data_block_quadlets;
 642                 *syt = 0;
 643 
 644                 if (*data_block_counter == UINT_MAX)
 645                         *data_block_counter = 0;
 646         }
 647 
 648         trace_amdtp_packet(s, cycle, cip_header, *payload_length, *data_blocks,
 649                            *data_block_counter, index);
 650 
 651         return err;
 652 }
 653 
 654 // In CYCLE_TIMER register of IEEE 1394, 7 bits are used to represent second. On
 655 // the other hand, in DMA descriptors of 1394 OHCI, 3 bits are used to represent
 656 // it. Thus, via Linux firewire subsystem, we can get the 3 bits for second.
 657 static inline u32 compute_cycle_count(__be32 ctx_header_tstamp)
 658 {
 659         u32 tstamp = be32_to_cpu(ctx_header_tstamp) & HEADER_TSTAMP_MASK;
 660         return (((tstamp >> 13) & 0x07) * 8000) + (tstamp & 0x1fff);
 661 }
 662 
 663 static inline u32 increment_cycle_count(u32 cycle, unsigned int addend)
 664 {
 665         cycle += addend;
 666         if (cycle >= 8 * CYCLES_PER_SECOND)
 667                 cycle -= 8 * CYCLES_PER_SECOND;
 668         return cycle;
 669 }
 670 
 671 // Align to actual cycle count for the packet which is going to be scheduled.
 672 // This module queued the same number of isochronous cycle as QUEUE_LENGTH to
 673 // skip isochronous cycle, therefore it's OK to just increment the cycle by
 674 // QUEUE_LENGTH for scheduled cycle.
 675 static inline u32 compute_it_cycle(const __be32 ctx_header_tstamp)
 676 {
 677         u32 cycle = compute_cycle_count(ctx_header_tstamp);
 678         return increment_cycle_count(cycle, QUEUE_LENGTH);
 679 }
 680 
 681 static int generate_device_pkt_descs(struct amdtp_stream *s,
 682                                      struct pkt_desc *descs,
 683                                      const __be32 *ctx_header,
 684                                      unsigned int packets)
 685 {
 686         unsigned int dbc = s->data_block_counter;
 687         int i;
 688         int err;
 689 
 690         for (i = 0; i < packets; ++i) {
 691                 struct pkt_desc *desc = descs + i;
 692                 unsigned int index = (s->packet_index + i) % QUEUE_LENGTH;
 693                 unsigned int cycle;
 694                 unsigned int payload_length;
 695                 unsigned int data_blocks;
 696                 unsigned int syt;
 697 
 698                 cycle = compute_cycle_count(ctx_header[1]);
 699 
 700                 err = parse_ir_ctx_header(s, cycle, ctx_header, &payload_length,
 701                                           &data_blocks, &dbc, &syt, i);
 702                 if (err < 0)
 703                         return err;
 704 
 705                 desc->cycle = cycle;
 706                 desc->syt = syt;
 707                 desc->data_blocks = data_blocks;
 708                 desc->data_block_counter = dbc;
 709                 desc->ctx_payload = s->buffer.packets[index].buffer;
 710 
 711                 if (!(s->flags & CIP_DBC_IS_END_EVENT))
 712                         dbc = (dbc + desc->data_blocks) & 0xff;
 713 
 714                 ctx_header +=
 715                         s->ctx_data.tx.ctx_header_size / sizeof(*ctx_header);
 716         }
 717 
 718         s->data_block_counter = dbc;
 719 
 720         return 0;
 721 }
 722 
 723 static void generate_ideal_pkt_descs(struct amdtp_stream *s,
 724                                      struct pkt_desc *descs,
 725                                      const __be32 *ctx_header,
 726                                      unsigned int packets)
 727 {
 728         unsigned int dbc = s->data_block_counter;
 729         int i;
 730 
 731         for (i = 0; i < packets; ++i) {
 732                 struct pkt_desc *desc = descs + i;
 733                 unsigned int index = (s->packet_index + i) % QUEUE_LENGTH;
 734 
 735                 desc->cycle = compute_it_cycle(*ctx_header);
 736                 desc->syt = calculate_syt(s, desc->cycle);
 737                 desc->data_blocks = calculate_data_blocks(s, desc->syt);
 738 
 739                 if (s->flags & CIP_DBC_IS_END_EVENT)
 740                         dbc = (dbc + desc->data_blocks) & 0xff;
 741 
 742                 desc->data_block_counter = dbc;
 743 
 744                 if (!(s->flags & CIP_DBC_IS_END_EVENT))
 745                         dbc = (dbc + desc->data_blocks) & 0xff;
 746 
 747                 desc->ctx_payload = s->buffer.packets[index].buffer;
 748 
 749                 ++ctx_header;
 750         }
 751 
 752         s->data_block_counter = dbc;
 753 }
 754 
 755 static inline void cancel_stream(struct amdtp_stream *s)
 756 {
 757         s->packet_index = -1;
 758         if (in_interrupt())
 759                 amdtp_stream_pcm_abort(s);
 760         WRITE_ONCE(s->pcm_buffer_pointer, SNDRV_PCM_POS_XRUN);
 761 }
 762 
 763 static void process_ctx_payloads(struct amdtp_stream *s,
 764                                  const struct pkt_desc *descs,
 765                                  unsigned int packets)
 766 {
 767         struct snd_pcm_substream *pcm;
 768         unsigned int pcm_frames;
 769 
 770         pcm = READ_ONCE(s->pcm);
 771         pcm_frames = s->process_ctx_payloads(s, descs, packets, pcm);
 772         if (pcm)
 773                 update_pcm_pointers(s, pcm, pcm_frames);
 774 }
 775 
 776 static void out_stream_callback(struct fw_iso_context *context, u32 tstamp,
 777                                 size_t header_length, void *header,
 778                                 void *private_data)
 779 {
 780         struct amdtp_stream *s = private_data;
 781         const __be32 *ctx_header = header;
 782         unsigned int packets = header_length / sizeof(*ctx_header);
 783         int i;
 784 
 785         if (s->packet_index < 0)
 786                 return;
 787 
 788         generate_ideal_pkt_descs(s, s->pkt_descs, ctx_header, packets);
 789 
 790         process_ctx_payloads(s, s->pkt_descs, packets);
 791 
 792         for (i = 0; i < packets; ++i) {
 793                 const struct pkt_desc *desc = s->pkt_descs + i;
 794                 unsigned int syt;
 795                 struct {
 796                         struct fw_iso_packet params;
 797                         __be32 header[IT_PKT_HEADER_SIZE_CIP / sizeof(__be32)];
 798                 } template = { {0}, {0} };
 799 
 800                 if (s->ctx_data.rx.syt_override < 0)
 801                         syt = desc->syt;
 802                 else
 803                         syt = s->ctx_data.rx.syt_override;
 804 
 805                 build_it_pkt_header(s, desc->cycle, &template.params,
 806                                     desc->data_blocks, desc->data_block_counter,
 807                                     syt, i);
 808 
 809                 if (queue_out_packet(s, &template.params) < 0) {
 810                         cancel_stream(s);
 811                         return;
 812                 }
 813         }
 814 
 815         fw_iso_context_queue_flush(s->context);
 816 }
 817 
 818 static void in_stream_callback(struct fw_iso_context *context, u32 tstamp,
 819                                size_t header_length, void *header,
 820                                void *private_data)
 821 {
 822         struct amdtp_stream *s = private_data;
 823         unsigned int packets;
 824         __be32 *ctx_header = header;
 825         int i;
 826         int err;
 827 
 828         if (s->packet_index < 0)
 829                 return;
 830 
 831         // The number of packets in buffer.
 832         packets = header_length / s->ctx_data.tx.ctx_header_size;
 833 
 834         err = generate_device_pkt_descs(s, s->pkt_descs, ctx_header, packets);
 835         if (err < 0) {
 836                 if (err != -EAGAIN) {
 837                         cancel_stream(s);
 838                         return;
 839                 }
 840         } else {
 841                 process_ctx_payloads(s, s->pkt_descs, packets);
 842         }
 843 
 844         for (i = 0; i < packets; ++i) {
 845                 struct fw_iso_packet params = {0};
 846 
 847                 if (queue_in_packet(s, &params) < 0) {
 848                         cancel_stream(s);
 849                         return;
 850                 }
 851         }
 852 
 853         fw_iso_context_queue_flush(s->context);
 854 }
 855 
 856 /* this is executed one time */
 857 static void amdtp_stream_first_callback(struct fw_iso_context *context,
 858                                         u32 tstamp, size_t header_length,
 859                                         void *header, void *private_data)
 860 {
 861         struct amdtp_stream *s = private_data;
 862         const __be32 *ctx_header = header;
 863         u32 cycle;
 864 
 865         /*
 866          * For in-stream, first packet has come.
 867          * For out-stream, prepared to transmit first packet
 868          */
 869         s->callbacked = true;
 870         wake_up(&s->callback_wait);
 871 
 872         if (s->direction == AMDTP_IN_STREAM) {
 873                 cycle = compute_cycle_count(ctx_header[1]);
 874 
 875                 context->callback.sc = in_stream_callback;
 876         } else {
 877                 cycle = compute_it_cycle(*ctx_header);
 878 
 879                 context->callback.sc = out_stream_callback;
 880         }
 881 
 882         s->start_cycle = cycle;
 883 
 884         context->callback.sc(context, tstamp, header_length, header, s);
 885 }
 886 
 887 /**
 888  * amdtp_stream_start - start transferring packets
 889  * @s: the AMDTP stream to start
 890  * @channel: the isochronous channel on the bus
 891  * @speed: firewire speed code
 892  *
 893  * The stream cannot be started until it has been configured with
 894  * amdtp_stream_set_parameters() and it must be started before any PCM or MIDI
 895  * device can be started.
 896  */
 897 static int amdtp_stream_start(struct amdtp_stream *s, int channel, int speed)
 898 {
 899         static const struct {
 900                 unsigned int data_block;
 901                 unsigned int syt_offset;
 902         } *entry, initial_state[] = {
 903                 [CIP_SFC_32000]  = {  4, 3072 },
 904                 [CIP_SFC_48000]  = {  6, 1024 },
 905                 [CIP_SFC_96000]  = { 12, 1024 },
 906                 [CIP_SFC_192000] = { 24, 1024 },
 907                 [CIP_SFC_44100]  = {  0,   67 },
 908                 [CIP_SFC_88200]  = {  0,   67 },
 909                 [CIP_SFC_176400] = {  0,   67 },
 910         };
 911         unsigned int ctx_header_size;
 912         unsigned int max_ctx_payload_size;
 913         enum dma_data_direction dir;
 914         int type, tag, err;
 915 
 916         mutex_lock(&s->mutex);
 917 
 918         if (WARN_ON(amdtp_stream_running(s) ||
 919                     (s->data_block_quadlets < 1))) {
 920                 err = -EBADFD;
 921                 goto err_unlock;
 922         }
 923 
 924         if (s->direction == AMDTP_IN_STREAM) {
 925                 s->data_block_counter = UINT_MAX;
 926         } else {
 927                 entry = &initial_state[s->sfc];
 928 
 929                 s->data_block_counter = 0;
 930                 s->ctx_data.rx.data_block_state = entry->data_block;
 931                 s->ctx_data.rx.syt_offset_state = entry->syt_offset;
 932                 s->ctx_data.rx.last_syt_offset = TICKS_PER_CYCLE;
 933         }
 934 
 935         /* initialize packet buffer */
 936         if (s->direction == AMDTP_IN_STREAM) {
 937                 dir = DMA_FROM_DEVICE;
 938                 type = FW_ISO_CONTEXT_RECEIVE;
 939                 if (!(s->flags & CIP_NO_HEADER))
 940                         ctx_header_size = IR_CTX_HEADER_SIZE_CIP;
 941                 else
 942                         ctx_header_size = IR_CTX_HEADER_SIZE_NO_CIP;
 943 
 944                 max_ctx_payload_size = amdtp_stream_get_max_payload(s) -
 945                                        ctx_header_size;
 946         } else {
 947                 dir = DMA_TO_DEVICE;
 948                 type = FW_ISO_CONTEXT_TRANSMIT;
 949                 ctx_header_size = 0;    // No effect for IT context.
 950 
 951                 max_ctx_payload_size = amdtp_stream_get_max_payload(s);
 952                 if (!(s->flags & CIP_NO_HEADER))
 953                         max_ctx_payload_size -= IT_PKT_HEADER_SIZE_CIP;
 954         }
 955 
 956         err = iso_packets_buffer_init(&s->buffer, s->unit, QUEUE_LENGTH,
 957                                       max_ctx_payload_size, dir);
 958         if (err < 0)
 959                 goto err_unlock;
 960 
 961         s->context = fw_iso_context_create(fw_parent_device(s->unit)->card,
 962                                           type, channel, speed, ctx_header_size,
 963                                           amdtp_stream_first_callback, s);
 964         if (IS_ERR(s->context)) {
 965                 err = PTR_ERR(s->context);
 966                 if (err == -EBUSY)
 967                         dev_err(&s->unit->device,
 968                                 "no free stream on this controller\n");
 969                 goto err_buffer;
 970         }
 971 
 972         amdtp_stream_update(s);
 973 
 974         if (s->direction == AMDTP_IN_STREAM) {
 975                 s->ctx_data.tx.max_ctx_payload_length = max_ctx_payload_size;
 976                 s->ctx_data.tx.ctx_header_size = ctx_header_size;
 977         }
 978 
 979         if (s->flags & CIP_NO_HEADER)
 980                 s->tag = TAG_NO_CIP_HEADER;
 981         else
 982                 s->tag = TAG_CIP;
 983 
 984         s->pkt_descs = kcalloc(INTERRUPT_INTERVAL, sizeof(*s->pkt_descs),
 985                                GFP_KERNEL);
 986         if (!s->pkt_descs) {
 987                 err = -ENOMEM;
 988                 goto err_context;
 989         }
 990 
 991         s->packet_index = 0;
 992         do {
 993                 struct fw_iso_packet params;
 994                 if (s->direction == AMDTP_IN_STREAM) {
 995                         err = queue_in_packet(s, &params);
 996                 } else {
 997                         params.header_length = 0;
 998                         params.payload_length = 0;
 999                         err = queue_out_packet(s, &params);
1000                 }
1001                 if (err < 0)
1002                         goto err_pkt_descs;
1003         } while (s->packet_index > 0);
1004 
1005         /* NOTE: TAG1 matches CIP. This just affects in stream. */
1006         tag = FW_ISO_CONTEXT_MATCH_TAG1;
1007         if ((s->flags & CIP_EMPTY_WITH_TAG0) || (s->flags & CIP_NO_HEADER))
1008                 tag |= FW_ISO_CONTEXT_MATCH_TAG0;
1009 
1010         s->callbacked = false;
1011         err = fw_iso_context_start(s->context, -1, 0, tag);
1012         if (err < 0)
1013                 goto err_pkt_descs;
1014 
1015         mutex_unlock(&s->mutex);
1016 
1017         return 0;
1018 err_pkt_descs:
1019         kfree(s->pkt_descs);
1020 err_context:
1021         fw_iso_context_destroy(s->context);
1022         s->context = ERR_PTR(-1);
1023 err_buffer:
1024         iso_packets_buffer_destroy(&s->buffer, s->unit);
1025 err_unlock:
1026         mutex_unlock(&s->mutex);
1027 
1028         return err;
1029 }
1030 
1031 /**
1032  * amdtp_stream_pcm_pointer - get the PCM buffer position
1033  * @s: the AMDTP stream that transports the PCM data
1034  *
1035  * Returns the current buffer position, in frames.
1036  */
1037 unsigned long amdtp_stream_pcm_pointer(struct amdtp_stream *s)
1038 {
1039         /*
1040          * This function is called in software IRQ context of period_tasklet or
1041          * process context.
1042          *
1043          * When the software IRQ context was scheduled by software IRQ context
1044          * of IR/IT contexts, queued packets were already handled. Therefore,
1045          * no need to flush the queue in buffer anymore.
1046          *
1047          * When the process context reach here, some packets will be already
1048          * queued in the buffer. These packets should be handled immediately
1049          * to keep better granularity of PCM pointer.
1050          *
1051          * Later, the process context will sometimes schedules software IRQ
1052          * context of the period_tasklet. Then, no need to flush the queue by
1053          * the same reason as described for IR/IT contexts.
1054          */
1055         if (!in_interrupt() && amdtp_stream_running(s))
1056                 fw_iso_context_flush_completions(s->context);
1057 
1058         return READ_ONCE(s->pcm_buffer_pointer);
1059 }
1060 EXPORT_SYMBOL(amdtp_stream_pcm_pointer);
1061 
1062 /**
1063  * amdtp_stream_pcm_ack - acknowledge queued PCM frames
1064  * @s: the AMDTP stream that transfers the PCM frames
1065  *
1066  * Returns zero always.
1067  */
1068 int amdtp_stream_pcm_ack(struct amdtp_stream *s)
1069 {
1070         /*
1071          * Process isochronous packets for recent isochronous cycle to handle
1072          * queued PCM frames.
1073          */
1074         if (amdtp_stream_running(s))
1075                 fw_iso_context_flush_completions(s->context);
1076 
1077         return 0;
1078 }
1079 EXPORT_SYMBOL(amdtp_stream_pcm_ack);
1080 
1081 /**
1082  * amdtp_stream_update - update the stream after a bus reset
1083  * @s: the AMDTP stream
1084  */
1085 void amdtp_stream_update(struct amdtp_stream *s)
1086 {
1087         /* Precomputing. */
1088         WRITE_ONCE(s->source_node_id_field,
1089                    (fw_parent_device(s->unit)->card->node_id << CIP_SID_SHIFT) & CIP_SID_MASK);
1090 }
1091 EXPORT_SYMBOL(amdtp_stream_update);
1092 
1093 /**
1094  * amdtp_stream_stop - stop sending packets
1095  * @s: the AMDTP stream to stop
1096  *
1097  * All PCM and MIDI devices of the stream must be stopped before the stream
1098  * itself can be stopped.
1099  */
1100 static void amdtp_stream_stop(struct amdtp_stream *s)
1101 {
1102         mutex_lock(&s->mutex);
1103 
1104         if (!amdtp_stream_running(s)) {
1105                 mutex_unlock(&s->mutex);
1106                 return;
1107         }
1108 
1109         tasklet_kill(&s->period_tasklet);
1110         fw_iso_context_stop(s->context);
1111         fw_iso_context_destroy(s->context);
1112         s->context = ERR_PTR(-1);
1113         iso_packets_buffer_destroy(&s->buffer, s->unit);
1114         kfree(s->pkt_descs);
1115 
1116         s->callbacked = false;
1117 
1118         mutex_unlock(&s->mutex);
1119 }
1120 
1121 /**
1122  * amdtp_stream_pcm_abort - abort the running PCM device
1123  * @s: the AMDTP stream about to be stopped
1124  *
1125  * If the isochronous stream needs to be stopped asynchronously, call this
1126  * function first to stop the PCM device.
1127  */
1128 void amdtp_stream_pcm_abort(struct amdtp_stream *s)
1129 {
1130         struct snd_pcm_substream *pcm;
1131 
1132         pcm = READ_ONCE(s->pcm);
1133         if (pcm)
1134                 snd_pcm_stop_xrun(pcm);
1135 }
1136 EXPORT_SYMBOL(amdtp_stream_pcm_abort);
1137 
1138 /**
1139  * amdtp_domain_init - initialize an AMDTP domain structure
1140  * @d: the AMDTP domain to initialize.
1141  */
1142 int amdtp_domain_init(struct amdtp_domain *d)
1143 {
1144         INIT_LIST_HEAD(&d->streams);
1145 
1146         return 0;
1147 }
1148 EXPORT_SYMBOL_GPL(amdtp_domain_init);
1149 
1150 /**
1151  * amdtp_domain_destroy - destroy an AMDTP domain structure
1152  * @d: the AMDTP domain to destroy.
1153  */
1154 void amdtp_domain_destroy(struct amdtp_domain *d)
1155 {
1156         // At present nothing to do.
1157         return;
1158 }
1159 EXPORT_SYMBOL_GPL(amdtp_domain_destroy);
1160 
1161 /**
1162  * amdtp_domain_add_stream - register isoc context into the domain.
1163  * @d: the AMDTP domain.
1164  * @s: the AMDTP stream.
1165  * @channel: the isochronous channel on the bus.
1166  * @speed: firewire speed code.
1167  */
1168 int amdtp_domain_add_stream(struct amdtp_domain *d, struct amdtp_stream *s,
1169                             int channel, int speed)
1170 {
1171         struct amdtp_stream *tmp;
1172 
1173         list_for_each_entry(tmp, &d->streams, list) {
1174                 if (s == tmp)
1175                         return -EBUSY;
1176         }
1177 
1178         list_add(&s->list, &d->streams);
1179 
1180         s->channel = channel;
1181         s->speed = speed;
1182 
1183         return 0;
1184 }
1185 EXPORT_SYMBOL_GPL(amdtp_domain_add_stream);
1186 
1187 /**
1188  * amdtp_domain_start - start sending packets for isoc context in the domain.
1189  * @d: the AMDTP domain.
1190  */
1191 int amdtp_domain_start(struct amdtp_domain *d)
1192 {
1193         struct amdtp_stream *s;
1194         int err = 0;
1195 
1196         list_for_each_entry(s, &d->streams, list) {
1197                 err = amdtp_stream_start(s, s->channel, s->speed);
1198                 if (err < 0)
1199                         break;
1200         }
1201 
1202         if (err < 0) {
1203                 list_for_each_entry(s, &d->streams, list)
1204                         amdtp_stream_stop(s);
1205         }
1206 
1207         return err;
1208 }
1209 EXPORT_SYMBOL_GPL(amdtp_domain_start);
1210 
1211 /**
1212  * amdtp_domain_stop - stop sending packets for isoc context in the same domain.
1213  * @d: the AMDTP domain to which the isoc contexts belong.
1214  */
1215 void amdtp_domain_stop(struct amdtp_domain *d)
1216 {
1217         struct amdtp_stream *s, *next;
1218 
1219         list_for_each_entry_safe(s, next, &d->streams, list) {
1220                 list_del(&s->list);
1221 
1222                 amdtp_stream_stop(s);
1223         }
1224 }
1225 EXPORT_SYMBOL_GPL(amdtp_domain_stop);
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root/sound/firewire/amdtp-stream.c

DEFINITIONS
