amdtp.c 28.8 KB
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/*
 * Audio and Music Data Transmission Protocol (IEC 61883-6) streams
 * with Common Isochronous Packet (IEC 61883-1) headers
 *
 * Copyright (c) Clemens Ladisch <clemens@ladisch.de>
 * Licensed under the terms of the GNU General Public License, version 2.
 */

#include <linux/device.h>
#include <linux/err.h>
#include <linux/firewire.h>
#include <linux/module.h>
#include <linux/slab.h>
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#include <linux/sched.h>
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#include <sound/pcm.h>
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#include <sound/pcm_params.h>
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#include <sound/rawmidi.h>
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#include "amdtp.h"

#define TICKS_PER_CYCLE		3072
#define CYCLES_PER_SECOND	8000
#define TICKS_PER_SECOND	(TICKS_PER_CYCLE * CYCLES_PER_SECOND)

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/*
 * Nominally 3125 bytes/second, but the MIDI port's clock might be
 * 1% too slow, and the bus clock 100 ppm too fast.
 */
#define MIDI_BYTES_PER_SECOND	3093

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/*
 * Several devices look only at the first eight data blocks.
 * In any case, this is more than enough for the MIDI data rate.
 */
#define MAX_MIDI_RX_BLOCKS	8

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#define TRANSFER_DELAY_TICKS	0x2e00 /* 479.17 microseconds */
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/* isochronous header parameters */
#define ISO_DATA_LENGTH_SHIFT	16
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#define TAG_CIP			1

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/* common isochronous packet header parameters */
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#define CIP_EOH			(1u << 31)
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#define CIP_EOH_MASK		0x80000000
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#define CIP_FMT_AM		(0x10 << 24)
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#define CIP_FMT_MASK		0x3f000000
#define CIP_SYT_MASK		0x0000ffff
#define CIP_SYT_NO_INFO		0xffff
#define CIP_FDF_MASK		0x00ff0000
#define CIP_FDF_SFC_SHIFT	16

/*
 * Audio and Music transfer protocol specific parameters
 * only "Clock-based rate control mode" is supported
 */
#define AMDTP_FDF_AM824		(0 << (CIP_FDF_SFC_SHIFT + 3))
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#define AMDTP_FDF_NO_DATA	0xff
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#define AMDTP_DBS_MASK		0x00ff0000
#define AMDTP_DBS_SHIFT		16
#define AMDTP_DBC_MASK		0x000000ff
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/* TODO: make these configurable */
#define INTERRUPT_INTERVAL	16
#define QUEUE_LENGTH		48

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#define IN_PACKET_HEADER_SIZE	4
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#define OUT_PACKET_HEADER_SIZE	0

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static void pcm_period_tasklet(unsigned long data);

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/**
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 * amdtp_stream_init - initialize an AMDTP stream structure
 * @s: the AMDTP stream to initialize
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 * @unit: the target of the stream
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 * @dir: the direction of stream
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 * @flags: the packet transmission method to use
 */
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int amdtp_stream_init(struct amdtp_stream *s, struct fw_unit *unit,
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		      enum amdtp_stream_direction dir, enum cip_flags flags)
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{
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	s->unit = unit;
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	s->direction = dir;
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	s->flags = flags;
	s->context = ERR_PTR(-1);
	mutex_init(&s->mutex);
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	tasklet_init(&s->period_tasklet, pcm_period_tasklet, (unsigned long)s);
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	s->packet_index = 0;
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	init_waitqueue_head(&s->callback_wait);
	s->callbacked = false;
	s->sync_slave = NULL;

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	return 0;
}
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EXPORT_SYMBOL(amdtp_stream_init);
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/**
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 * amdtp_stream_destroy - free stream resources
 * @s: the AMDTP stream to destroy
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 */
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void amdtp_stream_destroy(struct amdtp_stream *s)
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{
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	WARN_ON(amdtp_stream_running(s));
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	mutex_destroy(&s->mutex);
}
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EXPORT_SYMBOL(amdtp_stream_destroy);
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const unsigned int amdtp_syt_intervals[CIP_SFC_COUNT] = {
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	[CIP_SFC_32000]  =  8,
	[CIP_SFC_44100]  =  8,
	[CIP_SFC_48000]  =  8,
	[CIP_SFC_88200]  = 16,
	[CIP_SFC_96000]  = 16,
	[CIP_SFC_176400] = 32,
	[CIP_SFC_192000] = 32,
};
EXPORT_SYMBOL(amdtp_syt_intervals);

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const unsigned int amdtp_rate_table[CIP_SFC_COUNT] = {
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	[CIP_SFC_32000]  =  32000,
	[CIP_SFC_44100]  =  44100,
	[CIP_SFC_48000]  =  48000,
	[CIP_SFC_88200]  =  88200,
	[CIP_SFC_96000]  =  96000,
	[CIP_SFC_176400] = 176400,
	[CIP_SFC_192000] = 192000,
};
EXPORT_SYMBOL(amdtp_rate_table);

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/**
 * amdtp_stream_add_pcm_hw_constraints - add hw constraints for PCM substream
 * @s:		the AMDTP stream, which must be initialized.
 * @runtime:	the PCM substream runtime
 */
int amdtp_stream_add_pcm_hw_constraints(struct amdtp_stream *s,
					struct snd_pcm_runtime *runtime)
{
	int err;

	/* AM824 in IEC 61883-6 can deliver 24bit data */
	err = snd_pcm_hw_constraint_msbits(runtime, 0, 32, 24);
	if (err < 0)
		goto end;

	/*
	 * Currently firewire-lib processes 16 packets in one software
	 * interrupt callback. This equals to 2msec but actually the
	 * interval of the interrupts has a jitter.
	 * Additionally, even if adding a constraint to fit period size to
	 * 2msec, actual calculated frames per period doesn't equal to 2msec,
	 * depending on sampling rate.
	 * Anyway, the interval to call snd_pcm_period_elapsed() cannot 2msec.
	 * Here let us use 5msec for safe period interrupt.
	 */
	err = snd_pcm_hw_constraint_minmax(runtime,
					   SNDRV_PCM_HW_PARAM_PERIOD_TIME,
					   5000, UINT_MAX);
	if (err < 0)
		goto end;

	/* Non-Blocking stream has no more constraints */
	if (!(s->flags & CIP_BLOCKING))
		goto end;

	/*
	 * One AMDTP packet can include some frames. In blocking mode, the
	 * number equals to SYT_INTERVAL. So the number is 8, 16 or 32,
	 * depending on its sampling rate. For accurate period interrupt, it's
	 * preferrable to aligh period/buffer sizes to current SYT_INTERVAL.
	 *
	 * TODO: These constraints can be improved with propper rules.
	 * Currently apply LCM of SYT_INTEVALs.
	 */
	err = snd_pcm_hw_constraint_step(runtime, 0,
					 SNDRV_PCM_HW_PARAM_PERIOD_SIZE, 32);
	if (err < 0)
		goto end;
	err = snd_pcm_hw_constraint_step(runtime, 0,
					 SNDRV_PCM_HW_PARAM_BUFFER_SIZE, 32);
end:
	return err;
}
EXPORT_SYMBOL(amdtp_stream_add_pcm_hw_constraints);

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/**
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 * amdtp_stream_set_parameters - set stream parameters
 * @s: the AMDTP stream to configure
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 * @rate: the sample rate
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 * @pcm_channels: the number of PCM samples in each data block, to be encoded
 *                as AM824 multi-bit linear audio
 * @midi_ports: the number of MIDI ports (i.e., MPX-MIDI Data Channels)
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 *
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 * The parameters must be set before the stream is started, and must not be
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 * changed while the stream is running.
 */
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void amdtp_stream_set_parameters(struct amdtp_stream *s,
				 unsigned int rate,
				 unsigned int pcm_channels,
				 unsigned int midi_ports)
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{
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	unsigned int i, sfc, midi_channels;
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	midi_channels = DIV_ROUND_UP(midi_ports, 8);

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	if (WARN_ON(amdtp_stream_running(s)) |
	    WARN_ON(pcm_channels > AMDTP_MAX_CHANNELS_FOR_PCM) |
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	    WARN_ON(midi_channels > AMDTP_MAX_CHANNELS_FOR_MIDI))
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		return;

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	for (sfc = 0; sfc < ARRAY_SIZE(amdtp_rate_table); ++sfc)
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		if (amdtp_rate_table[sfc] == rate)
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			goto sfc_found;
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	WARN_ON(1);
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	return;

sfc_found:
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	s->pcm_channels = pcm_channels;
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	s->sfc = sfc;
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	s->data_block_quadlets = s->pcm_channels + midi_channels;
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	s->midi_ports = midi_ports;

	s->syt_interval = amdtp_syt_intervals[sfc];
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	/* default buffering in the device */
	s->transfer_delay = TRANSFER_DELAY_TICKS - TICKS_PER_CYCLE;
	if (s->flags & CIP_BLOCKING)
		/* additional buffering needed to adjust for no-data packets */
		s->transfer_delay += TICKS_PER_SECOND * s->syt_interval / rate;
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	/* init the position map for PCM and MIDI channels */
	for (i = 0; i < pcm_channels; i++)
		s->pcm_positions[i] = i;
	s->midi_position = s->pcm_channels;
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	/*
	 * We do not know the actual MIDI FIFO size of most devices.  Just
	 * assume two bytes, i.e., one byte can be received over the bus while
	 * the previous one is transmitted over MIDI.
	 * (The value here is adjusted for midi_ratelimit_per_packet().)
	 */
	s->midi_fifo_limit = rate - MIDI_BYTES_PER_SECOND * s->syt_interval + 1;
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}
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EXPORT_SYMBOL(amdtp_stream_set_parameters);
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/**
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 * amdtp_stream_get_max_payload - get the stream's packet size
 * @s: the AMDTP stream
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 *
 * This function must not be called before the stream has been configured
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 * with amdtp_stream_set_parameters().
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 */
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unsigned int amdtp_stream_get_max_payload(struct amdtp_stream *s)
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{
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	return 8 + s->syt_interval * s->data_block_quadlets * 4;
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}
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EXPORT_SYMBOL(amdtp_stream_get_max_payload);
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static void amdtp_write_s16(struct amdtp_stream *s,
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			    struct snd_pcm_substream *pcm,
			    __be32 *buffer, unsigned int frames);
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static void amdtp_write_s32(struct amdtp_stream *s,
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			    struct snd_pcm_substream *pcm,
			    __be32 *buffer, unsigned int frames);
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static void amdtp_read_s32(struct amdtp_stream *s,
			   struct snd_pcm_substream *pcm,
			   __be32 *buffer, unsigned int frames);
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/**
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 * amdtp_stream_set_pcm_format - set the PCM format
 * @s: the AMDTP stream to configure
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 * @format: the format of the ALSA PCM device
 *
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 * The sample format must be set after the other paramters (rate/PCM channels/
 * MIDI) and before the stream is started, and must not be changed while the
 * stream is running.
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 */
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void amdtp_stream_set_pcm_format(struct amdtp_stream *s,
				 snd_pcm_format_t format)
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{
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	if (WARN_ON(amdtp_stream_pcm_running(s)))
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		return;

	switch (format) {
	default:
		WARN_ON(1);
		/* fall through */
	case SNDRV_PCM_FORMAT_S16:
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		if (s->direction == AMDTP_OUT_STREAM) {
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			s->transfer_samples = amdtp_write_s16;
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			break;
		}
		WARN_ON(1);
		/* fall through */
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	case SNDRV_PCM_FORMAT_S32:
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		if (s->direction == AMDTP_OUT_STREAM)
			s->transfer_samples = amdtp_write_s32;
		else
			s->transfer_samples = amdtp_read_s32;
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		break;
	}
}
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EXPORT_SYMBOL(amdtp_stream_set_pcm_format);
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/**
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 * amdtp_stream_pcm_prepare - prepare PCM device for running
 * @s: the AMDTP stream
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 *
 * This function should be called from the PCM device's .prepare callback.
 */
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void amdtp_stream_pcm_prepare(struct amdtp_stream *s)
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{
	tasklet_kill(&s->period_tasklet);
	s->pcm_buffer_pointer = 0;
	s->pcm_period_pointer = 0;
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	s->pointer_flush = true;
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}
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EXPORT_SYMBOL(amdtp_stream_pcm_prepare);
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static unsigned int calculate_data_blocks(struct amdtp_stream *s)
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{
	unsigned int phase, data_blocks;

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	if (s->flags & CIP_BLOCKING)
		data_blocks = s->syt_interval;
	else if (!cip_sfc_is_base_44100(s->sfc)) {
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		/* Sample_rate / 8000 is an integer, and precomputed. */
		data_blocks = s->data_block_state;
	} else {
		phase = s->data_block_state;

		/*
		 * This calculates the number of data blocks per packet so that
		 * 1) the overall rate is correct and exactly synchronized to
		 *    the bus clock, and
		 * 2) packets with a rounded-up number of blocks occur as early
		 *    as possible in the sequence (to prevent underruns of the
		 *    device's buffer).
		 */
		if (s->sfc == CIP_SFC_44100)
			/* 6 6 5 6 5 6 5 ... */
			data_blocks = 5 + ((phase & 1) ^
					   (phase == 0 || phase >= 40));
		else
			/* 12 11 11 11 11 ... or 23 22 22 22 22 ... */
			data_blocks = 11 * (s->sfc >> 1) + (phase == 0);
		if (++phase >= (80 >> (s->sfc >> 1)))
			phase = 0;
		s->data_block_state = phase;
	}

	return data_blocks;
}

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static unsigned int calculate_syt(struct amdtp_stream *s,
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				  unsigned int cycle)
{
	unsigned int syt_offset, phase, index, syt;

	if (s->last_syt_offset < TICKS_PER_CYCLE) {
		if (!cip_sfc_is_base_44100(s->sfc))
			syt_offset = s->last_syt_offset + s->syt_offset_state;
		else {
		/*
		 * The time, in ticks, of the n'th SYT_INTERVAL sample is:
		 *   n * SYT_INTERVAL * 24576000 / sample_rate
		 * Modulo TICKS_PER_CYCLE, the difference between successive
		 * elements is about 1386.23.  Rounding the results of this
		 * formula to the SYT precision results in a sequence of
		 * differences that begins with:
		 *   1386 1386 1387 1386 1386 1386 1387 1386 1386 1386 1387 ...
		 * This code generates _exactly_ the same sequence.
		 */
			phase = s->syt_offset_state;
			index = phase % 13;
			syt_offset = s->last_syt_offset;
			syt_offset += 1386 + ((index && !(index & 3)) ||
					      phase == 146);
			if (++phase >= 147)
				phase = 0;
			s->syt_offset_state = phase;
		}
	} else
		syt_offset = s->last_syt_offset - TICKS_PER_CYCLE;
	s->last_syt_offset = syt_offset;

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	if (syt_offset < TICKS_PER_CYCLE) {
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		syt_offset += s->transfer_delay;
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		syt = (cycle + syt_offset / TICKS_PER_CYCLE) << 12;
		syt += syt_offset % TICKS_PER_CYCLE;
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		return syt & CIP_SYT_MASK;
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	} else {
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		return CIP_SYT_NO_INFO;
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	}
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}

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static void amdtp_write_s32(struct amdtp_stream *s,
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			    struct snd_pcm_substream *pcm,
			    __be32 *buffer, unsigned int frames)
{
	struct snd_pcm_runtime *runtime = pcm->runtime;
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	unsigned int channels, remaining_frames, i, c;
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	const u32 *src;

	channels = s->pcm_channels;
	src = (void *)runtime->dma_area +
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			frames_to_bytes(runtime, s->pcm_buffer_pointer);
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	remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer;

	for (i = 0; i < frames; ++i) {
		for (c = 0; c < channels; ++c) {
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			buffer[s->pcm_positions[c]] =
					cpu_to_be32((*src >> 8) | 0x40000000);
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			src++;
		}
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		buffer += s->data_block_quadlets;
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		if (--remaining_frames == 0)
			src = (void *)runtime->dma_area;
	}
}

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static void amdtp_write_s16(struct amdtp_stream *s,
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			    struct snd_pcm_substream *pcm,
			    __be32 *buffer, unsigned int frames)
{
	struct snd_pcm_runtime *runtime = pcm->runtime;
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	unsigned int channels, remaining_frames, i, c;
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	const u16 *src;

	channels = s->pcm_channels;
	src = (void *)runtime->dma_area +
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			frames_to_bytes(runtime, s->pcm_buffer_pointer);
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	remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer;

	for (i = 0; i < frames; ++i) {
		for (c = 0; c < channels; ++c) {
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			buffer[s->pcm_positions[c]] =
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					cpu_to_be32((*src << 8) | 0x42000000);
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			src++;
		}
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		buffer += s->data_block_quadlets;
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		if (--remaining_frames == 0)
			src = (void *)runtime->dma_area;
	}
}

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static void amdtp_read_s32(struct amdtp_stream *s,
			   struct snd_pcm_substream *pcm,
			   __be32 *buffer, unsigned int frames)
{
	struct snd_pcm_runtime *runtime = pcm->runtime;
	unsigned int channels, remaining_frames, i, c;
	u32 *dst;

	channels = s->pcm_channels;
	dst  = (void *)runtime->dma_area +
			frames_to_bytes(runtime, s->pcm_buffer_pointer);
	remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer;

	for (i = 0; i < frames; ++i) {
		for (c = 0; c < channels; ++c) {
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			*dst = be32_to_cpu(buffer[s->pcm_positions[c]]) << 8;
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			dst++;
		}
		buffer += s->data_block_quadlets;
		if (--remaining_frames == 0)
			dst = (void *)runtime->dma_area;
	}
}

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static void amdtp_fill_pcm_silence(struct amdtp_stream *s,
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				   __be32 *buffer, unsigned int frames)
{
	unsigned int i, c;

	for (i = 0; i < frames; ++i) {
		for (c = 0; c < s->pcm_channels; ++c)
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			buffer[s->pcm_positions[c]] = cpu_to_be32(0x40000000);
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		buffer += s->data_block_quadlets;
	}
}

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/*
 * To avoid sending MIDI bytes at too high a rate, assume that the receiving
 * device has a FIFO, and track how much it is filled.  This values increases
 * by one whenever we send one byte in a packet, but the FIFO empties at
 * a constant rate independent of our packet rate.  One packet has syt_interval
 * samples, so the number of bytes that empty out of the FIFO, per packet(!),
 * is MIDI_BYTES_PER_SECOND * syt_interval / sample_rate.  To avoid storing
 * fractional values, the values in midi_fifo_used[] are measured in bytes
 * multiplied by the sample rate.
 */
static bool midi_ratelimit_per_packet(struct amdtp_stream *s, unsigned int port)
{
	int used;

	used = s->midi_fifo_used[port];
	if (used == 0) /* common shortcut */
		return true;

	used -= MIDI_BYTES_PER_SECOND * s->syt_interval;
	used = max(used, 0);
	s->midi_fifo_used[port] = used;

	return used < s->midi_fifo_limit;
}

static void midi_rate_use_one_byte(struct amdtp_stream *s, unsigned int port)
{
	s->midi_fifo_used[port] += amdtp_rate_table[s->sfc];
}

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static void amdtp_fill_midi(struct amdtp_stream *s,
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			    __be32 *buffer, unsigned int frames)
{
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	unsigned int f, port;
	u8 *b;

	for (f = 0; f < frames; f++) {
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		b = (u8 *)&buffer[s->midi_position];
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		port = (s->data_block_counter + f) % 8;
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		if (f < MAX_MIDI_RX_BLOCKS &&
		    midi_ratelimit_per_packet(s, port) &&
		    s->midi[port] != NULL &&
		    snd_rawmidi_transmit(s->midi[port], &b[1], 1) == 1) {
			midi_rate_use_one_byte(s, port);
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			b[0] = 0x81;
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		} else {
			b[0] = 0x80;
			b[1] = 0;
		}
		b[2] = 0;
		b[3] = 0;
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		buffer += s->data_block_quadlets;
	}
}

static void amdtp_pull_midi(struct amdtp_stream *s,
			    __be32 *buffer, unsigned int frames)
{
	unsigned int f, port;
	int len;
	u8 *b;

	for (f = 0; f < frames; f++) {
		port = (s->data_block_counter + f) % 8;
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		b = (u8 *)&buffer[s->midi_position];
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		len = b[0] - 0x80;
		if ((1 <= len) &&  (len <= 3) && (s->midi[port]))
			snd_rawmidi_receive(s->midi[port], b + 1, len);

		buffer += s->data_block_quadlets;
	}
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}

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static void update_pcm_pointers(struct amdtp_stream *s,
				struct snd_pcm_substream *pcm,
				unsigned int frames)
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{
	unsigned int ptr;

	/*
	 * In IEC 61883-6, one data block represents one event. In ALSA, one
	 * event equals to one PCM frame. But Dice has a quirk to transfer
	 * two PCM frames in one data block.
	 */
	if (s->double_pcm_frames)
		frames *= 2;
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	ptr = s->pcm_buffer_pointer + frames;
	if (ptr >= pcm->runtime->buffer_size)
		ptr -= pcm->runtime->buffer_size;
	ACCESS_ONCE(s->pcm_buffer_pointer) = ptr;

	s->pcm_period_pointer += frames;
	if (s->pcm_period_pointer >= pcm->runtime->period_size) {
		s->pcm_period_pointer -= pcm->runtime->period_size;
		s->pointer_flush = false;
		tasklet_hi_schedule(&s->period_tasklet);
	}
}

static void pcm_period_tasklet(unsigned long data)
{
	struct amdtp_stream *s = (void *)data;
	struct snd_pcm_substream *pcm = ACCESS_ONCE(s->pcm);

	if (pcm)
		snd_pcm_period_elapsed(pcm);
}

static int queue_packet(struct amdtp_stream *s,
			unsigned int header_length,
			unsigned int payload_length, bool skip)
{
	struct fw_iso_packet p = {0};
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	int err = 0;

	if (IS_ERR(s->context))
		goto end;
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	p.interrupt = IS_ALIGNED(s->packet_index + 1, INTERRUPT_INTERVAL);
	p.tag = TAG_CIP;
	p.header_length = header_length;
	p.payload_length = (!skip) ? payload_length : 0;
	p.skip = skip;
	err = fw_iso_context_queue(s->context, &p, &s->buffer.iso_buffer,
				   s->buffer.packets[s->packet_index].offset);
	if (err < 0) {
		dev_err(&s->unit->device, "queueing error: %d\n", err);
		goto end;
	}

	if (++s->packet_index >= QUEUE_LENGTH)
		s->packet_index = 0;
end:
	return err;
}

static inline int queue_out_packet(struct amdtp_stream *s,
				   unsigned int payload_length, bool skip)
{
	return queue_packet(s, OUT_PACKET_HEADER_SIZE,
			    payload_length, skip);
}

630 631 632 633 634 635
static inline int queue_in_packet(struct amdtp_stream *s)
{
	return queue_packet(s, IN_PACKET_HEADER_SIZE,
			    amdtp_stream_get_max_payload(s), false);
}

636
static void handle_out_packet(struct amdtp_stream *s, unsigned int syt)
637 638
{
	__be32 *buffer;
639
	unsigned int data_blocks, payload_length;
640 641
	struct snd_pcm_substream *pcm;

642 643 644
	if (s->packet_index < 0)
		return;

645
	/* this module generate empty packet for 'no data' */
646
	if (!(s->flags & CIP_BLOCKING) || (syt != CIP_SYT_NO_INFO))
647
		data_blocks = calculate_data_blocks(s);
648 649
	else
		data_blocks = 0;
650

651
	buffer = s->buffer.packets[s->packet_index].buffer;
652
	buffer[0] = cpu_to_be32(ACCESS_ONCE(s->source_node_id_field) |
653
				(s->data_block_quadlets << AMDTP_DBS_SHIFT) |
654 655
				s->data_block_counter);
	buffer[1] = cpu_to_be32(CIP_EOH | CIP_FMT_AM | AMDTP_FDF_AM824 |
656
				(s->sfc << CIP_FDF_SFC_SHIFT) | syt);
657 658 659 660 661 662 663 664 665 666 667 668
	buffer += 2;

	pcm = ACCESS_ONCE(s->pcm);
	if (pcm)
		s->transfer_samples(s, pcm, buffer, data_blocks);
	else
		amdtp_fill_pcm_silence(s, buffer, data_blocks);
	if (s->midi_ports)
		amdtp_fill_midi(s, buffer, data_blocks);

	s->data_block_counter = (s->data_block_counter + data_blocks) & 0xff;

669 670
	payload_length = 8 + data_blocks * 4 * s->data_block_quadlets;
	if (queue_out_packet(s, payload_length, false) < 0) {
671
		s->packet_index = -1;
672
		amdtp_stream_pcm_abort(s);
673 674
		return;
	}
675

676
	if (pcm)
677
		update_pcm_pointers(s, pcm, data_blocks);
678 679
}

680 681 682 683 684
static void handle_in_packet(struct amdtp_stream *s,
			     unsigned int payload_quadlets,
			     __be32 *buffer)
{
	u32 cip_header[2];
685 686
	unsigned int data_blocks, data_block_quadlets, data_block_counter,
		     dbc_interval;
687
	struct snd_pcm_substream *pcm = NULL;
688
	bool lost;
689 690 691 692 693 694

	cip_header[0] = be32_to_cpu(buffer[0]);
	cip_header[1] = be32_to_cpu(buffer[1]);

	/*
	 * This module supports 'Two-quadlet CIP header with SYT field'.
695
	 * For convenience, also check FMT field is AM824 or not.
696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720
	 */
	if (((cip_header[0] & CIP_EOH_MASK) == CIP_EOH) ||
	    ((cip_header[1] & CIP_EOH_MASK) != CIP_EOH) ||
	    ((cip_header[1] & CIP_FMT_MASK) != CIP_FMT_AM)) {
		dev_info_ratelimited(&s->unit->device,
				"Invalid CIP header for AMDTP: %08X:%08X\n",
				cip_header[0], cip_header[1]);
		goto end;
	}

	/* Calculate data blocks */
	if (payload_quadlets < 3 ||
	    ((cip_header[1] & CIP_FDF_MASK) ==
				(AMDTP_FDF_NO_DATA << CIP_FDF_SFC_SHIFT))) {
		data_blocks = 0;
	} else {
		data_block_quadlets =
			(cip_header[0] & AMDTP_DBS_MASK) >> AMDTP_DBS_SHIFT;
		/* avoid division by zero */
		if (data_block_quadlets == 0) {
			dev_info_ratelimited(&s->unit->device,
				"Detect invalid value in dbs field: %08X\n",
				cip_header[0]);
			goto err;
		}
721 722
		if (s->flags & CIP_WRONG_DBS)
			data_block_quadlets = s->data_block_quadlets;
723 724 725 726 727 728

		data_blocks = (payload_quadlets - 2) / data_block_quadlets;
	}

	/* Check data block counter continuity */
	data_block_counter = cip_header[0] & AMDTP_DBC_MASK;
729 730 731 732
	if (data_blocks == 0 && (s->flags & CIP_EMPTY_HAS_WRONG_DBC) &&
	    s->data_block_counter != UINT_MAX)
		data_block_counter = s->data_block_counter;

733 734
	if (((s->flags & CIP_SKIP_DBC_ZERO_CHECK) && data_block_counter == 0) ||
	    (s->data_block_counter == UINT_MAX)) {
735 736
		lost = false;
	} else if (!(s->flags & CIP_DBC_IS_END_EVENT)) {
737
		lost = data_block_counter != s->data_block_counter;
738 739 740 741 742 743
	} else {
		if ((data_blocks > 0) && (s->tx_dbc_interval > 0))
			dbc_interval = s->tx_dbc_interval;
		else
			dbc_interval = data_blocks;

744
		lost = data_block_counter !=
745 746
		       ((s->data_block_counter + dbc_interval) & 0xff);
	}
747 748

	if (lost) {
749 750 751 752 753 754 755 756 757 758 759 760
		dev_info(&s->unit->device,
			 "Detect discontinuity of CIP: %02X %02X\n",
			 s->data_block_counter, data_block_counter);
		goto err;
	}

	if (data_blocks > 0) {
		buffer += 2;

		pcm = ACCESS_ONCE(s->pcm);
		if (pcm)
			s->transfer_samples(s, pcm, buffer, data_blocks);
761 762 763

		if (s->midi_ports)
			amdtp_pull_midi(s, buffer, data_blocks);
764 765
	}

766 767 768 769 770
	if (s->flags & CIP_DBC_IS_END_EVENT)
		s->data_block_counter = data_block_counter;
	else
		s->data_block_counter =
				(data_block_counter + data_blocks) & 0xff;
771 772 773 774 775 776 777 778 779 780 781 782 783
end:
	if (queue_in_packet(s) < 0)
		goto err;

	if (pcm)
		update_pcm_pointers(s, pcm, data_blocks);

	return;
err:
	s->packet_index = -1;
	amdtp_stream_pcm_abort(s);
}

784 785 786
static void out_stream_callback(struct fw_iso_context *context, u32 cycle,
				size_t header_length, void *header,
				void *private_data)
787
{
788
	struct amdtp_stream *s = private_data;
789
	unsigned int i, syt, packets = header_length / 4;
790 791 792 793 794 795 796 797

	/*
	 * Compute the cycle of the last queued packet.
	 * (We need only the four lowest bits for the SYT, so we can ignore
	 * that bits 0-11 must wrap around at 3072.)
	 */
	cycle += QUEUE_LENGTH - packets;

798 799 800 801
	for (i = 0; i < packets; ++i) {
		syt = calculate_syt(s, ++cycle);
		handle_out_packet(s, syt);
	}
802
	fw_iso_context_queue_flush(s->context);
803 804
}

805 806 807 808 809
static void in_stream_callback(struct fw_iso_context *context, u32 cycle,
			       size_t header_length, void *header,
			       void *private_data)
{
	struct amdtp_stream *s = private_data;
810
	unsigned int p, syt, packets, payload_quadlets;
811 812 813 814 815 816 817
	__be32 *buffer, *headers = header;

	/* The number of packets in buffer */
	packets = header_length / IN_PACKET_HEADER_SIZE;

	for (p = 0; p < packets; p++) {
		if (s->packet_index < 0)
818 819
			break;

820 821
		buffer = s->buffer.packets[s->packet_index].buffer;

822 823 824 825 826 827
		/* Process sync slave stream */
		if (s->sync_slave && s->sync_slave->callbacked) {
			syt = be32_to_cpu(buffer[1]) & CIP_SYT_MASK;
			handle_out_packet(s->sync_slave, syt);
		}

828 829 830 831 832 833
		/* The number of quadlets in this packet */
		payload_quadlets =
			(be32_to_cpu(headers[p]) >> ISO_DATA_LENGTH_SHIFT) / 4;
		handle_in_packet(s, payload_quadlets, buffer);
	}

834 835 836 837 838 839 840 841 842 843 844 845 846 847
	/* Queueing error or detecting discontinuity */
	if (s->packet_index < 0) {
		/* Abort sync slave. */
		if (s->sync_slave) {
			s->sync_slave->packet_index = -1;
			amdtp_stream_pcm_abort(s->sync_slave);
		}
		return;
	}

	/* when sync to device, flush the packets for slave stream */
	if (s->sync_slave && s->sync_slave->callbacked)
		fw_iso_context_queue_flush(s->sync_slave->context);

848 849 850
	fw_iso_context_queue_flush(s->context);
}

851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882
/* processing is done by master callback */
static void slave_stream_callback(struct fw_iso_context *context, u32 cycle,
				  size_t header_length, void *header,
				  void *private_data)
{
	return;
}

/* this is executed one time */
static void amdtp_stream_first_callback(struct fw_iso_context *context,
					u32 cycle, size_t header_length,
					void *header, void *private_data)
{
	struct amdtp_stream *s = private_data;

	/*
	 * For in-stream, first packet has come.
	 * For out-stream, prepared to transmit first packet
	 */
	s->callbacked = true;
	wake_up(&s->callback_wait);

	if (s->direction == AMDTP_IN_STREAM)
		context->callback.sc = in_stream_callback;
	else if ((s->flags & CIP_BLOCKING) && (s->flags & CIP_SYNC_TO_DEVICE))
		context->callback.sc = slave_stream_callback;
	else
		context->callback.sc = out_stream_callback;

	context->callback.sc(context, cycle, header_length, header, s);
}

883
/**
884 885
 * amdtp_stream_start - start transferring packets
 * @s: the AMDTP stream to start
886 887 888 889
 * @channel: the isochronous channel on the bus
 * @speed: firewire speed code
 *
 * The stream cannot be started until it has been configured with
890 891
 * amdtp_stream_set_parameters() and it must be started before any PCM or MIDI
 * device can be started.
892
 */
893
int amdtp_stream_start(struct amdtp_stream *s, int channel, int speed)
894 895 896 897 898 899 900 901 902 903 904 905 906
{
	static const struct {
		unsigned int data_block;
		unsigned int syt_offset;
	} initial_state[] = {
		[CIP_SFC_32000]  = {  4, 3072 },
		[CIP_SFC_48000]  = {  6, 1024 },
		[CIP_SFC_96000]  = { 12, 1024 },
		[CIP_SFC_192000] = { 24, 1024 },
		[CIP_SFC_44100]  = {  0,   67 },
		[CIP_SFC_88200]  = {  0,   67 },
		[CIP_SFC_176400] = {  0,   67 },
	};
907 908
	unsigned int header_size;
	enum dma_data_direction dir;
909
	int type, tag, err;
910 911 912

	mutex_lock(&s->mutex);

913
	if (WARN_ON(amdtp_stream_running(s) ||
914
		    (s->data_block_quadlets < 1))) {
915 916 917 918
		err = -EBADFD;
		goto err_unlock;
	}

919 920 921 922 923
	if (s->direction == AMDTP_IN_STREAM &&
	    s->flags & CIP_SKIP_INIT_DBC_CHECK)
		s->data_block_counter = UINT_MAX;
	else
		s->data_block_counter = 0;
924 925 926 927
	s->data_block_state = initial_state[s->sfc].data_block;
	s->syt_offset_state = initial_state[s->sfc].syt_offset;
	s->last_syt_offset = TICKS_PER_CYCLE;

928 929 930 931 932 933 934 935 936 937
	/* initialize packet buffer */
	if (s->direction == AMDTP_IN_STREAM) {
		dir = DMA_FROM_DEVICE;
		type = FW_ISO_CONTEXT_RECEIVE;
		header_size = IN_PACKET_HEADER_SIZE;
	} else {
		dir = DMA_TO_DEVICE;
		type = FW_ISO_CONTEXT_TRANSMIT;
		header_size = OUT_PACKET_HEADER_SIZE;
	}
938
	err = iso_packets_buffer_init(&s->buffer, s->unit, QUEUE_LENGTH,
939
				      amdtp_stream_get_max_payload(s), dir);
940 941 942 943
	if (err < 0)
		goto err_unlock;

	s->context = fw_iso_context_create(fw_parent_device(s->unit)->card,
944
					   type, channel, speed, header_size,
945
					   amdtp_stream_first_callback, s);
946 947 948 949
	if (IS_ERR(s->context)) {
		err = PTR_ERR(s->context);
		if (err == -EBUSY)
			dev_err(&s->unit->device,
950
				"no free stream on this controller\n");
951 952 953
		goto err_buffer;
	}

954
	amdtp_stream_update(s);
955

956
	s->packet_index = 0;
957
	do {
958 959 960 961
		if (s->direction == AMDTP_IN_STREAM)
			err = queue_in_packet(s);
		else
			err = queue_out_packet(s, 0, true);
962 963 964
		if (err < 0)
			goto err_context;
	} while (s->packet_index > 0);
965

966
	/* NOTE: TAG1 matches CIP. This just affects in stream. */
967 968 969 970
	tag = FW_ISO_CONTEXT_MATCH_TAG1;
	if (s->flags & CIP_EMPTY_WITH_TAG0)
		tag |= FW_ISO_CONTEXT_MATCH_TAG0;

971
	s->callbacked = false;
972
	err = fw_iso_context_start(s->context, -1, 0, tag);
973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989
	if (err < 0)
		goto err_context;

	mutex_unlock(&s->mutex);

	return 0;

err_context:
	fw_iso_context_destroy(s->context);
	s->context = ERR_PTR(-1);
err_buffer:
	iso_packets_buffer_destroy(&s->buffer, s->unit);
err_unlock:
	mutex_unlock(&s->mutex);

	return err;
}
990
EXPORT_SYMBOL(amdtp_stream_start);
991

992
/**
993 994
 * amdtp_stream_pcm_pointer - get the PCM buffer position
 * @s: the AMDTP stream that transports the PCM data
995 996 997
 *
 * Returns the current buffer position, in frames.
 */
998
unsigned long amdtp_stream_pcm_pointer(struct amdtp_stream *s)
999
{
1000
	/* this optimization is allowed to be racy */
1001
	if (s->pointer_flush && amdtp_stream_running(s))
1002 1003 1004
		fw_iso_context_flush_completions(s->context);
	else
		s->pointer_flush = true;
1005 1006 1007

	return ACCESS_ONCE(s->pcm_buffer_pointer);
}
1008
EXPORT_SYMBOL(amdtp_stream_pcm_pointer);
1009

1010
/**
1011 1012
 * amdtp_stream_update - update the stream after a bus reset
 * @s: the AMDTP stream
1013
 */
1014
void amdtp_stream_update(struct amdtp_stream *s)
1015 1016 1017 1018
{
	ACCESS_ONCE(s->source_node_id_field) =
		(fw_parent_device(s->unit)->card->node_id & 0x3f) << 24;
}
1019
EXPORT_SYMBOL(amdtp_stream_update);
1020 1021

/**
1022 1023
 * amdtp_stream_stop - stop sending packets
 * @s: the AMDTP stream to stop
1024 1025 1026 1027
 *
 * All PCM and MIDI devices of the stream must be stopped before the stream
 * itself can be stopped.
 */
1028
void amdtp_stream_stop(struct amdtp_stream *s)
1029 1030 1031
{
	mutex_lock(&s->mutex);

1032
	if (!amdtp_stream_running(s)) {
1033 1034 1035 1036
		mutex_unlock(&s->mutex);
		return;
	}

1037
	tasklet_kill(&s->period_tasklet);
1038 1039 1040 1041 1042
	fw_iso_context_stop(s->context);
	fw_iso_context_destroy(s->context);
	s->context = ERR_PTR(-1);
	iso_packets_buffer_destroy(&s->buffer, s->unit);

1043 1044
	s->callbacked = false;

1045 1046
	mutex_unlock(&s->mutex);
}
1047
EXPORT_SYMBOL(amdtp_stream_stop);
1048 1049

/**
1050
 * amdtp_stream_pcm_abort - abort the running PCM device
1051 1052 1053 1054 1055
 * @s: the AMDTP stream about to be stopped
 *
 * If the isochronous stream needs to be stopped asynchronously, call this
 * function first to stop the PCM device.
 */
1056
void amdtp_stream_pcm_abort(struct amdtp_stream *s)
1057 1058 1059 1060
{
	struct snd_pcm_substream *pcm;

	pcm = ACCESS_ONCE(s->pcm);
1061 1062
	if (pcm)
		snd_pcm_stop_xrun(pcm);
1063
}
1064
EXPORT_SYMBOL(amdtp_stream_pcm_abort);