2 * Audio and Music Data Transmission Protocol (IEC 61883-6) streams
3 * with Common Isochronous Packet (IEC 61883-1) headers
5 * Copyright (c) Clemens Ladisch <clemens@ladisch.de>
6 * Licensed under the terms of the GNU General Public License, version 2.
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"
18 #define TICKS_PER_CYCLE 3072
19 #define CYCLES_PER_SECOND 8000
20 #define TICKS_PER_SECOND (TICKS_PER_CYCLE * CYCLES_PER_SECOND)
22 #define TRANSFER_DELAY_TICKS 0x2e00 /* 479.17 microseconds */
24 /* isochronous header parameters */
25 #define ISO_DATA_LENGTH_SHIFT 16
28 /* common isochronous packet header parameters */
29 #define CIP_EOH_SHIFT 31
30 #define CIP_EOH (1u << CIP_EOH_SHIFT)
31 #define CIP_EOH_MASK 0x80000000
32 #define CIP_SID_SHIFT 24
33 #define CIP_SID_MASK 0x3f000000
34 #define CIP_DBS_MASK 0x00ff0000
35 #define CIP_DBS_SHIFT 16
36 #define CIP_DBC_MASK 0x000000ff
37 #define CIP_FMT_SHIFT 24
38 #define CIP_FMT_MASK 0x3f000000
39 #define CIP_FDF_MASK 0x00ff0000
40 #define CIP_FDF_SHIFT 16
41 #define CIP_SYT_MASK 0x0000ffff
42 #define CIP_SYT_NO_INFO 0xffff
44 /* Audio and Music transfer protocol specific parameters */
45 #define CIP_FMT_AM 0x10
46 #define AMDTP_FDF_NO_DATA 0xff
48 /* TODO: make these configurable */
49 #define INTERRUPT_INTERVAL 16
50 #define QUEUE_LENGTH 48
52 #define IN_PACKET_HEADER_SIZE 4
53 #define OUT_PACKET_HEADER_SIZE 0
55 static void pcm_period_tasklet(unsigned long data);
58 * amdtp_stream_init - initialize an AMDTP stream structure
59 * @s: the AMDTP stream to initialize
60 * @unit: the target of the stream
61 * @dir: the direction of stream
62 * @flags: the packet transmission method to use
63 * @fmt: the value of fmt field in CIP header
64 * @process_data_blocks: callback handler to process data blocks
65 * @protocol_size: the size to allocate newly for protocol
67 int amdtp_stream_init(struct amdtp_stream *s, struct fw_unit *unit,
68 enum amdtp_stream_direction dir, enum cip_flags flags,
70 amdtp_stream_process_data_blocks_t process_data_blocks,
71 unsigned int protocol_size)
73 if (process_data_blocks == NULL)
76 s->protocol = kzalloc(protocol_size, GFP_KERNEL);
83 s->context = ERR_PTR(-1);
84 mutex_init(&s->mutex);
85 tasklet_init(&s->period_tasklet, pcm_period_tasklet, (unsigned long)s);
88 init_waitqueue_head(&s->callback_wait);
89 s->callbacked = false;
93 s->process_data_blocks = process_data_blocks;
97 EXPORT_SYMBOL(amdtp_stream_init);
100 * amdtp_stream_destroy - free stream resources
101 * @s: the AMDTP stream to destroy
103 void amdtp_stream_destroy(struct amdtp_stream *s)
105 /* Not initialized. */
106 if (s->protocol == NULL)
109 WARN_ON(amdtp_stream_running(s));
111 mutex_destroy(&s->mutex);
113 EXPORT_SYMBOL(amdtp_stream_destroy);
115 const unsigned int amdtp_syt_intervals[CIP_SFC_COUNT] = {
119 [CIP_SFC_88200] = 16,
120 [CIP_SFC_96000] = 16,
121 [CIP_SFC_176400] = 32,
122 [CIP_SFC_192000] = 32,
124 EXPORT_SYMBOL(amdtp_syt_intervals);
126 const unsigned int amdtp_rate_table[CIP_SFC_COUNT] = {
127 [CIP_SFC_32000] = 32000,
128 [CIP_SFC_44100] = 44100,
129 [CIP_SFC_48000] = 48000,
130 [CIP_SFC_88200] = 88200,
131 [CIP_SFC_96000] = 96000,
132 [CIP_SFC_176400] = 176400,
133 [CIP_SFC_192000] = 192000,
135 EXPORT_SYMBOL(amdtp_rate_table);
138 * amdtp_stream_add_pcm_hw_constraints - add hw constraints for PCM substream
139 * @s: the AMDTP stream, which must be initialized.
140 * @runtime: the PCM substream runtime
142 int amdtp_stream_add_pcm_hw_constraints(struct amdtp_stream *s,
143 struct snd_pcm_runtime *runtime)
148 * Currently firewire-lib processes 16 packets in one software
149 * interrupt callback. This equals to 2msec but actually the
150 * interval of the interrupts has a jitter.
151 * Additionally, even if adding a constraint to fit period size to
152 * 2msec, actual calculated frames per period doesn't equal to 2msec,
153 * depending on sampling rate.
154 * Anyway, the interval to call snd_pcm_period_elapsed() cannot 2msec.
155 * Here let us use 5msec for safe period interrupt.
157 err = snd_pcm_hw_constraint_minmax(runtime,
158 SNDRV_PCM_HW_PARAM_PERIOD_TIME,
163 /* Non-Blocking stream has no more constraints */
164 if (!(s->flags & CIP_BLOCKING))
168 * One AMDTP packet can include some frames. In blocking mode, the
169 * number equals to SYT_INTERVAL. So the number is 8, 16 or 32,
170 * depending on its sampling rate. For accurate period interrupt, it's
171 * preferrable to align period/buffer sizes to current SYT_INTERVAL.
173 * TODO: These constraints can be improved with proper rules.
174 * Currently apply LCM of SYT_INTERVALs.
176 err = snd_pcm_hw_constraint_step(runtime, 0,
177 SNDRV_PCM_HW_PARAM_PERIOD_SIZE, 32);
180 err = snd_pcm_hw_constraint_step(runtime, 0,
181 SNDRV_PCM_HW_PARAM_BUFFER_SIZE, 32);
185 EXPORT_SYMBOL(amdtp_stream_add_pcm_hw_constraints);
188 * amdtp_stream_set_parameters - set stream parameters
189 * @s: the AMDTP stream to configure
190 * @rate: the sample rate
191 * @data_block_quadlets: the size of a data block in quadlet unit
193 * The parameters must be set before the stream is started, and must not be
194 * changed while the stream is running.
196 int amdtp_stream_set_parameters(struct amdtp_stream *s, unsigned int rate,
197 unsigned int data_block_quadlets)
201 for (sfc = 0; sfc < ARRAY_SIZE(amdtp_rate_table); ++sfc) {
202 if (amdtp_rate_table[sfc] == rate)
205 if (sfc == ARRAY_SIZE(amdtp_rate_table))
209 s->data_block_quadlets = data_block_quadlets;
210 s->syt_interval = amdtp_syt_intervals[sfc];
212 /* default buffering in the device */
213 s->transfer_delay = TRANSFER_DELAY_TICKS - TICKS_PER_CYCLE;
214 if (s->flags & CIP_BLOCKING)
215 /* additional buffering needed to adjust for no-data packets */
216 s->transfer_delay += TICKS_PER_SECOND * s->syt_interval / rate;
220 EXPORT_SYMBOL(amdtp_stream_set_parameters);
223 * amdtp_stream_get_max_payload - get the stream's packet size
224 * @s: the AMDTP stream
226 * This function must not be called before the stream has been configured
227 * with amdtp_stream_set_parameters().
229 unsigned int amdtp_stream_get_max_payload(struct amdtp_stream *s)
231 unsigned int multiplier = 1;
233 if (s->flags & CIP_JUMBO_PAYLOAD)
236 return 8 + s->syt_interval * s->data_block_quadlets * 4 * multiplier;
238 EXPORT_SYMBOL(amdtp_stream_get_max_payload);
241 * amdtp_stream_pcm_prepare - prepare PCM device for running
242 * @s: the AMDTP stream
244 * This function should be called from the PCM device's .prepare callback.
246 void amdtp_stream_pcm_prepare(struct amdtp_stream *s)
248 tasklet_kill(&s->period_tasklet);
249 s->pcm_buffer_pointer = 0;
250 s->pcm_period_pointer = 0;
251 s->pointer_flush = true;
253 EXPORT_SYMBOL(amdtp_stream_pcm_prepare);
255 static unsigned int calculate_data_blocks(struct amdtp_stream *s,
258 unsigned int phase, data_blocks;
261 if (s->flags & CIP_BLOCKING) {
262 /* This module generate empty packet for 'no data'. */
263 if (syt == CIP_SYT_NO_INFO)
266 data_blocks = s->syt_interval;
267 /* Non-blocking mode. */
269 if (!cip_sfc_is_base_44100(s->sfc)) {
270 /* Sample_rate / 8000 is an integer, and precomputed. */
271 data_blocks = s->data_block_state;
273 phase = s->data_block_state;
276 * This calculates the number of data blocks per packet so that
277 * 1) the overall rate is correct and exactly synchronized to
279 * 2) packets with a rounded-up number of blocks occur as early
280 * as possible in the sequence (to prevent underruns of the
283 if (s->sfc == CIP_SFC_44100)
284 /* 6 6 5 6 5 6 5 ... */
285 data_blocks = 5 + ((phase & 1) ^
286 (phase == 0 || phase >= 40));
288 /* 12 11 11 11 11 ... or 23 22 22 22 22 ... */
289 data_blocks = 11 * (s->sfc >> 1) + (phase == 0);
290 if (++phase >= (80 >> (s->sfc >> 1)))
292 s->data_block_state = phase;
299 static unsigned int calculate_syt(struct amdtp_stream *s,
302 unsigned int syt_offset, phase, index, syt;
304 if (s->last_syt_offset < TICKS_PER_CYCLE) {
305 if (!cip_sfc_is_base_44100(s->sfc))
306 syt_offset = s->last_syt_offset + s->syt_offset_state;
309 * The time, in ticks, of the n'th SYT_INTERVAL sample is:
310 * n * SYT_INTERVAL * 24576000 / sample_rate
311 * Modulo TICKS_PER_CYCLE, the difference between successive
312 * elements is about 1386.23. Rounding the results of this
313 * formula to the SYT precision results in a sequence of
314 * differences that begins with:
315 * 1386 1386 1387 1386 1386 1386 1387 1386 1386 1386 1387 ...
316 * This code generates _exactly_ the same sequence.
318 phase = s->syt_offset_state;
320 syt_offset = s->last_syt_offset;
321 syt_offset += 1386 + ((index && !(index & 3)) ||
325 s->syt_offset_state = phase;
328 syt_offset = s->last_syt_offset - TICKS_PER_CYCLE;
329 s->last_syt_offset = syt_offset;
331 if (syt_offset < TICKS_PER_CYCLE) {
332 syt_offset += s->transfer_delay;
333 syt = (cycle + syt_offset / TICKS_PER_CYCLE) << 12;
334 syt += syt_offset % TICKS_PER_CYCLE;
336 return syt & CIP_SYT_MASK;
338 return CIP_SYT_NO_INFO;
342 static void update_pcm_pointers(struct amdtp_stream *s,
343 struct snd_pcm_substream *pcm,
348 ptr = s->pcm_buffer_pointer + frames;
349 if (ptr >= pcm->runtime->buffer_size)
350 ptr -= pcm->runtime->buffer_size;
351 ACCESS_ONCE(s->pcm_buffer_pointer) = ptr;
353 s->pcm_period_pointer += frames;
354 if (s->pcm_period_pointer >= pcm->runtime->period_size) {
355 s->pcm_period_pointer -= pcm->runtime->period_size;
356 s->pointer_flush = false;
357 tasklet_hi_schedule(&s->period_tasklet);
361 static void pcm_period_tasklet(unsigned long data)
363 struct amdtp_stream *s = (void *)data;
364 struct snd_pcm_substream *pcm = ACCESS_ONCE(s->pcm);
367 snd_pcm_period_elapsed(pcm);
370 static int queue_packet(struct amdtp_stream *s,
371 unsigned int header_length,
372 unsigned int payload_length, bool skip)
374 struct fw_iso_packet p = {0};
377 if (IS_ERR(s->context))
380 p.interrupt = IS_ALIGNED(s->packet_index + 1, INTERRUPT_INTERVAL);
382 p.header_length = header_length;
383 p.payload_length = (!skip) ? payload_length : 0;
385 err = fw_iso_context_queue(s->context, &p, &s->buffer.iso_buffer,
386 s->buffer.packets[s->packet_index].offset);
388 dev_err(&s->unit->device, "queueing error: %d\n", err);
392 if (++s->packet_index >= QUEUE_LENGTH)
398 static inline int queue_out_packet(struct amdtp_stream *s,
399 unsigned int payload_length, bool skip)
401 return queue_packet(s, OUT_PACKET_HEADER_SIZE,
402 payload_length, skip);
405 static inline int queue_in_packet(struct amdtp_stream *s)
407 return queue_packet(s, IN_PACKET_HEADER_SIZE,
408 amdtp_stream_get_max_payload(s), false);
411 static int handle_out_packet(struct amdtp_stream *s, unsigned int data_blocks,
415 unsigned int payload_length;
416 unsigned int pcm_frames;
417 struct snd_pcm_substream *pcm;
419 buffer = s->buffer.packets[s->packet_index].buffer;
420 pcm_frames = s->process_data_blocks(s, buffer + 2, data_blocks, &syt);
422 buffer[0] = cpu_to_be32(ACCESS_ONCE(s->source_node_id_field) |
423 (s->data_block_quadlets << CIP_DBS_SHIFT) |
424 s->data_block_counter);
425 buffer[1] = cpu_to_be32(CIP_EOH |
426 ((s->fmt << CIP_FMT_SHIFT) & CIP_FMT_MASK) |
427 ((s->fdf << CIP_FDF_SHIFT) & CIP_FDF_MASK) |
428 (syt & CIP_SYT_MASK));
430 s->data_block_counter = (s->data_block_counter + data_blocks) & 0xff;
432 payload_length = 8 + data_blocks * 4 * s->data_block_quadlets;
433 if (queue_out_packet(s, payload_length, false) < 0)
436 pcm = ACCESS_ONCE(s->pcm);
437 if (pcm && pcm_frames > 0)
438 update_pcm_pointers(s, pcm, pcm_frames);
440 /* No need to return the number of handled data blocks. */
444 static int handle_in_packet(struct amdtp_stream *s,
445 unsigned int payload_quadlets, __be32 *buffer,
446 unsigned int *data_blocks, unsigned int syt)
449 unsigned int fmt, fdf;
450 unsigned int data_block_quadlets, data_block_counter, dbc_interval;
451 struct snd_pcm_substream *pcm;
452 unsigned int pcm_frames;
455 cip_header[0] = be32_to_cpu(buffer[0]);
456 cip_header[1] = be32_to_cpu(buffer[1]);
459 * This module supports 'Two-quadlet CIP header with SYT field'.
460 * For convenience, also check FMT field is AM824 or not.
462 if (((cip_header[0] & CIP_EOH_MASK) == CIP_EOH) ||
463 ((cip_header[1] & CIP_EOH_MASK) != CIP_EOH)) {
464 dev_info_ratelimited(&s->unit->device,
465 "Invalid CIP header for AMDTP: %08X:%08X\n",
466 cip_header[0], cip_header[1]);
472 /* Check valid protocol or not. */
473 fmt = (cip_header[1] & CIP_FMT_MASK) >> CIP_FMT_SHIFT;
475 dev_info_ratelimited(&s->unit->device,
476 "Detect unexpected protocol: %08x %08x\n",
477 cip_header[0], cip_header[1]);
483 /* Calculate data blocks */
484 fdf = (cip_header[1] & CIP_FDF_MASK) >> CIP_FDF_SHIFT;
485 if (payload_quadlets < 3 ||
486 (fmt == CIP_FMT_AM && fdf == AMDTP_FDF_NO_DATA)) {
489 data_block_quadlets =
490 (cip_header[0] & CIP_DBS_MASK) >> CIP_DBS_SHIFT;
491 /* avoid division by zero */
492 if (data_block_quadlets == 0) {
493 dev_err(&s->unit->device,
494 "Detect invalid value in dbs field: %08X\n",
498 if (s->flags & CIP_WRONG_DBS)
499 data_block_quadlets = s->data_block_quadlets;
501 *data_blocks = (payload_quadlets - 2) / data_block_quadlets;
504 /* Check data block counter continuity */
505 data_block_counter = cip_header[0] & CIP_DBC_MASK;
506 if (*data_blocks == 0 && (s->flags & CIP_EMPTY_HAS_WRONG_DBC) &&
507 s->data_block_counter != UINT_MAX)
508 data_block_counter = s->data_block_counter;
510 if (((s->flags & CIP_SKIP_DBC_ZERO_CHECK) &&
511 data_block_counter == s->tx_first_dbc) ||
512 s->data_block_counter == UINT_MAX) {
514 } else if (!(s->flags & CIP_DBC_IS_END_EVENT)) {
515 lost = data_block_counter != s->data_block_counter;
517 if ((*data_blocks > 0) && (s->tx_dbc_interval > 0))
518 dbc_interval = s->tx_dbc_interval;
520 dbc_interval = *data_blocks;
522 lost = data_block_counter !=
523 ((s->data_block_counter + dbc_interval) & 0xff);
527 dev_err(&s->unit->device,
528 "Detect discontinuity of CIP: %02X %02X\n",
529 s->data_block_counter, data_block_counter);
533 pcm_frames = s->process_data_blocks(s, buffer + 2, *data_blocks, &syt);
535 if (s->flags & CIP_DBC_IS_END_EVENT)
536 s->data_block_counter = data_block_counter;
538 s->data_block_counter =
539 (data_block_counter + *data_blocks) & 0xff;
541 if (queue_in_packet(s) < 0)
544 pcm = ACCESS_ONCE(s->pcm);
545 if (pcm && pcm_frames > 0)
546 update_pcm_pointers(s, pcm, pcm_frames);
552 * In CYCLE_TIMER register of IEEE 1394, 7 bits are used to represent second. On
553 * the other hand, in DMA descriptors of 1394 OHCI, 3 bits are used to represent
554 * it. Thus, via Linux firewire subsystem, we can get the 3 bits for second.
556 static inline u32 compute_cycle_count(u32 tstamp)
558 return (((tstamp >> 13) & 0x07) * 8000) + (tstamp & 0x1fff);
561 static inline u32 increment_cycle_count(u32 cycle, unsigned int addend)
564 if (cycle >= 8 * CYCLES_PER_SECOND)
565 cycle -= 8 * CYCLES_PER_SECOND;
569 static void out_stream_callback(struct fw_iso_context *context, u32 tstamp,
570 size_t header_length, void *header,
573 struct amdtp_stream *s = private_data;
574 unsigned int i, syt, packets = header_length / 4;
575 unsigned int data_blocks;
578 if (s->packet_index < 0)
581 cycle = compute_cycle_count(tstamp);
583 /* Align to actual cycle count for the last packet. */
584 cycle = increment_cycle_count(cycle, QUEUE_LENGTH - packets);
586 for (i = 0; i < packets; ++i) {
587 cycle = increment_cycle_count(cycle, 1);
588 syt = calculate_syt(s, cycle);
589 data_blocks = calculate_data_blocks(s, syt);
591 if (handle_out_packet(s, data_blocks, syt) < 0) {
592 s->packet_index = -1;
593 amdtp_stream_pcm_abort(s);
598 fw_iso_context_queue_flush(s->context);
601 static void in_stream_callback(struct fw_iso_context *context, u32 tstamp,
602 size_t header_length, void *header,
605 struct amdtp_stream *s = private_data;
606 unsigned int p, syt, packets;
607 unsigned int payload_quadlets, max_payload_quadlets;
608 unsigned int data_blocks;
609 __be32 *buffer, *headers = header;
611 if (s->packet_index < 0)
614 /* The number of packets in buffer */
615 packets = header_length / IN_PACKET_HEADER_SIZE;
617 /* For buffer-over-run prevention. */
618 max_payload_quadlets = amdtp_stream_get_max_payload(s) / 4;
620 for (p = 0; p < packets; p++) {
621 buffer = s->buffer.packets[s->packet_index].buffer;
623 /* The number of quadlets in this packet */
625 (be32_to_cpu(headers[p]) >> ISO_DATA_LENGTH_SHIFT) / 4;
626 if (payload_quadlets > max_payload_quadlets) {
627 dev_err(&s->unit->device,
628 "Detect jumbo payload: %02x %02x\n",
629 payload_quadlets, max_payload_quadlets);
630 s->packet_index = -1;
634 syt = be32_to_cpu(buffer[1]) & CIP_SYT_MASK;
635 if (handle_in_packet(s, payload_quadlets, buffer,
636 &data_blocks, syt) < 0) {
637 s->packet_index = -1;
641 /* Process sync slave stream */
642 if (s->sync_slave && s->sync_slave->callbacked) {
643 if (handle_out_packet(s->sync_slave,
644 data_blocks, syt) < 0) {
645 s->packet_index = -1;
651 /* Queueing error or detecting discontinuity */
652 if (s->packet_index < 0) {
653 amdtp_stream_pcm_abort(s);
655 /* Abort sync slave. */
657 s->sync_slave->packet_index = -1;
658 amdtp_stream_pcm_abort(s->sync_slave);
663 /* when sync to device, flush the packets for slave stream */
664 if (s->sync_slave && s->sync_slave->callbacked)
665 fw_iso_context_queue_flush(s->sync_slave->context);
667 fw_iso_context_queue_flush(s->context);
670 /* processing is done by master callback */
671 static void slave_stream_callback(struct fw_iso_context *context, u32 tstamp,
672 size_t header_length, void *header,
678 /* this is executed one time */
679 static void amdtp_stream_first_callback(struct fw_iso_context *context,
680 u32 tstamp, size_t header_length,
681 void *header, void *private_data)
683 struct amdtp_stream *s = private_data;
686 * For in-stream, first packet has come.
687 * For out-stream, prepared to transmit first packet
689 s->callbacked = true;
690 wake_up(&s->callback_wait);
692 if (s->direction == AMDTP_IN_STREAM)
693 context->callback.sc = in_stream_callback;
694 else if (s->flags & CIP_SYNC_TO_DEVICE)
695 context->callback.sc = slave_stream_callback;
697 context->callback.sc = out_stream_callback;
699 context->callback.sc(context, tstamp, header_length, header, s);
703 * amdtp_stream_start - start transferring packets
704 * @s: the AMDTP stream to start
705 * @channel: the isochronous channel on the bus
706 * @speed: firewire speed code
708 * The stream cannot be started until it has been configured with
709 * amdtp_stream_set_parameters() and it must be started before any PCM or MIDI
710 * device can be started.
712 int amdtp_stream_start(struct amdtp_stream *s, int channel, int speed)
714 static const struct {
715 unsigned int data_block;
716 unsigned int syt_offset;
717 } initial_state[] = {
718 [CIP_SFC_32000] = { 4, 3072 },
719 [CIP_SFC_48000] = { 6, 1024 },
720 [CIP_SFC_96000] = { 12, 1024 },
721 [CIP_SFC_192000] = { 24, 1024 },
722 [CIP_SFC_44100] = { 0, 67 },
723 [CIP_SFC_88200] = { 0, 67 },
724 [CIP_SFC_176400] = { 0, 67 },
726 unsigned int header_size;
727 enum dma_data_direction dir;
730 mutex_lock(&s->mutex);
732 if (WARN_ON(amdtp_stream_running(s) ||
733 (s->data_block_quadlets < 1))) {
738 if (s->direction == AMDTP_IN_STREAM &&
739 s->flags & CIP_SKIP_INIT_DBC_CHECK)
740 s->data_block_counter = UINT_MAX;
742 s->data_block_counter = 0;
743 s->data_block_state = initial_state[s->sfc].data_block;
744 s->syt_offset_state = initial_state[s->sfc].syt_offset;
745 s->last_syt_offset = TICKS_PER_CYCLE;
747 /* initialize packet buffer */
748 if (s->direction == AMDTP_IN_STREAM) {
749 dir = DMA_FROM_DEVICE;
750 type = FW_ISO_CONTEXT_RECEIVE;
751 header_size = IN_PACKET_HEADER_SIZE;
754 type = FW_ISO_CONTEXT_TRANSMIT;
755 header_size = OUT_PACKET_HEADER_SIZE;
757 err = iso_packets_buffer_init(&s->buffer, s->unit, QUEUE_LENGTH,
758 amdtp_stream_get_max_payload(s), dir);
762 s->context = fw_iso_context_create(fw_parent_device(s->unit)->card,
763 type, channel, speed, header_size,
764 amdtp_stream_first_callback, s);
765 if (IS_ERR(s->context)) {
766 err = PTR_ERR(s->context);
768 dev_err(&s->unit->device,
769 "no free stream on this controller\n");
773 amdtp_stream_update(s);
777 if (s->direction == AMDTP_IN_STREAM)
778 err = queue_in_packet(s);
780 err = queue_out_packet(s, 0, true);
783 } while (s->packet_index > 0);
785 /* NOTE: TAG1 matches CIP. This just affects in stream. */
786 tag = FW_ISO_CONTEXT_MATCH_TAG1;
787 if (s->flags & CIP_EMPTY_WITH_TAG0)
788 tag |= FW_ISO_CONTEXT_MATCH_TAG0;
790 s->callbacked = false;
791 err = fw_iso_context_start(s->context, -1, 0, tag);
795 mutex_unlock(&s->mutex);
800 fw_iso_context_destroy(s->context);
801 s->context = ERR_PTR(-1);
803 iso_packets_buffer_destroy(&s->buffer, s->unit);
805 mutex_unlock(&s->mutex);
809 EXPORT_SYMBOL(amdtp_stream_start);
812 * amdtp_stream_pcm_pointer - get the PCM buffer position
813 * @s: the AMDTP stream that transports the PCM data
815 * Returns the current buffer position, in frames.
817 unsigned long amdtp_stream_pcm_pointer(struct amdtp_stream *s)
819 /* this optimization is allowed to be racy */
820 if (s->pointer_flush && amdtp_stream_running(s))
821 fw_iso_context_flush_completions(s->context);
823 s->pointer_flush = true;
825 return ACCESS_ONCE(s->pcm_buffer_pointer);
827 EXPORT_SYMBOL(amdtp_stream_pcm_pointer);
830 * amdtp_stream_update - update the stream after a bus reset
831 * @s: the AMDTP stream
833 void amdtp_stream_update(struct amdtp_stream *s)
836 ACCESS_ONCE(s->source_node_id_field) =
837 (fw_parent_device(s->unit)->card->node_id << CIP_SID_SHIFT) &
840 EXPORT_SYMBOL(amdtp_stream_update);
843 * amdtp_stream_stop - stop sending packets
844 * @s: the AMDTP stream to stop
846 * All PCM and MIDI devices of the stream must be stopped before the stream
847 * itself can be stopped.
849 void amdtp_stream_stop(struct amdtp_stream *s)
851 mutex_lock(&s->mutex);
853 if (!amdtp_stream_running(s)) {
854 mutex_unlock(&s->mutex);
858 tasklet_kill(&s->period_tasklet);
859 fw_iso_context_stop(s->context);
860 fw_iso_context_destroy(s->context);
861 s->context = ERR_PTR(-1);
862 iso_packets_buffer_destroy(&s->buffer, s->unit);
864 s->callbacked = false;
866 mutex_unlock(&s->mutex);
868 EXPORT_SYMBOL(amdtp_stream_stop);
871 * amdtp_stream_pcm_abort - abort the running PCM device
872 * @s: the AMDTP stream about to be stopped
874 * If the isochronous stream needs to be stopped asynchronously, call this
875 * function first to stop the PCM device.
877 void amdtp_stream_pcm_abort(struct amdtp_stream *s)
879 struct snd_pcm_substream *pcm;
881 pcm = ACCESS_ONCE(s->pcm);
883 snd_pcm_stop_xrun(pcm);
885 EXPORT_SYMBOL(amdtp_stream_pcm_abort);