amdtp.c 25.6 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>
#include <sound/pcm.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)

#define TRANSFER_DELAY_TICKS	0x2e00 /* 479.17 µs */

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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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{
	s->unit = fw_unit_get(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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	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);
	fw_unit_put(s->unit);
}
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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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/**
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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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	static const unsigned int rates[] = {
		[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,
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	};
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	unsigned int sfc, midi_channels;
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	midi_channels = DIV_ROUND_UP(midi_ports, 8);

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

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	for (sfc = 0; sfc < CIP_SFC_COUNT; ++sfc)
		if (rates[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->dual_wire = (s->flags & CIP_HI_DUALWIRE) && sfc > CIP_SFC_96000;
	if (s->dual_wire) {
		sfc -= 2;
		rate /= 2;
		pcm_channels *= 2;
	}
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	s->sfc = sfc;
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	s->data_block_quadlets = pcm_channels + midi_channels;
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	s->pcm_channels = pcm_channels;
	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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}
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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_write_s16_dualwire(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_dualwire(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);
static void amdtp_read_s32_dualwire(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) {
			if (s->dual_wire)
				s->transfer_samples = amdtp_write_s16_dualwire;
			else
				s->transfer_samples = amdtp_write_s16;
			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) {
			if (s->dual_wire)
				s->transfer_samples = amdtp_write_s32_dualwire;
			else
				s->transfer_samples = amdtp_write_s32;
		} else {
			if (s->dual_wire)
				s->transfer_samples = amdtp_read_s32_dualwire;
			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;
	unsigned int channels, remaining_frames, frame_step, i, c;
	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;
	frame_step = s->data_block_quadlets - channels;

	for (i = 0; i < frames; ++i) {
		for (c = 0; c < channels; ++c) {
			*buffer = cpu_to_be32((*src >> 8) | 0x40000000);
			src++;
			buffer++;
		}
		buffer += frame_step;
		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;
	unsigned int channels, remaining_frames, frame_step, i, c;
	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;
	frame_step = s->data_block_quadlets - channels;

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

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static void amdtp_write_s32_dualwire(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;
	unsigned int channels, frame_adjust_1, frame_adjust_2, i, c;
	const u32 *src;

	channels = s->pcm_channels;
	src = (void *)runtime->dma_area +
			s->pcm_buffer_pointer * (runtime->frame_bits / 8);
	frame_adjust_1 = channels - 1;
	frame_adjust_2 = 1 - (s->data_block_quadlets - channels);

	channels /= 2;
	for (i = 0; i < frames; ++i) {
		for (c = 0; c < channels; ++c) {
			*buffer = cpu_to_be32((*src >> 8) | 0x40000000);
			src++;
			buffer += 2;
		}
		buffer -= frame_adjust_1;
		for (c = 0; c < channels; ++c) {
			*buffer = cpu_to_be32((*src >> 8) | 0x40000000);
			src++;
			buffer += 2;
		}
		buffer -= frame_adjust_2;
	}
}

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static void amdtp_write_s16_dualwire(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;
	unsigned int channels, frame_adjust_1, frame_adjust_2, i, c;
	const u16 *src;

	channels = s->pcm_channels;
	src = (void *)runtime->dma_area +
			s->pcm_buffer_pointer * (runtime->frame_bits / 8);
	frame_adjust_1 = channels - 1;
	frame_adjust_2 = 1 - (s->data_block_quadlets - channels);

	channels /= 2;
	for (i = 0; i < frames; ++i) {
		for (c = 0; c < channels; ++c) {
			*buffer = cpu_to_be32((*src << 8) | 0x40000000);
			src++;
			buffer += 2;
		}
		buffer -= frame_adjust_1;
		for (c = 0; c < channels; ++c) {
			*buffer = cpu_to_be32((*src << 8) | 0x40000000);
			src++;
			buffer += 2;
		}
		buffer -= frame_adjust_2;
	}
}

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

static void amdtp_read_s32_dualwire(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;

	dst = (void *)runtime->dma_area +
			frames_to_bytes(runtime, s->pcm_buffer_pointer);
	remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer;
	channels = s->pcm_channels / 2;

	for (i = 0; i < frames; ++i) {
		for (c = 0; c < channels; ++c) {
			*dst = be32_to_cpu(buffer[c * 2]) << 8;
			dst++;
		}
		buffer += 1;
		for (c = 0; c < channels; ++c) {
			*dst = be32_to_cpu(buffer[c * 2]) << 8;
			dst++;
		}
		buffer += s->data_block_quadlets - 1;
		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)
			buffer[c] = cpu_to_be32(0x40000000);
		buffer += s->data_block_quadlets;
	}
}

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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++) {
		buffer[s->pcm_channels + 1] = 0;
		b = (u8 *)&buffer[s->pcm_channels + 1];

		port = (s->data_block_counter + f) % 8;
		if ((s->midi[port] == NULL) ||
		    (snd_rawmidi_transmit(s->midi[port], b + 1, 1) <= 0))
			b[0] = 0x80;
		else
			b[0] = 0x81;

		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;
		b = (u8 *)&buffer[s->pcm_channels + 1];
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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)
{	unsigned int ptr;

	if (s->dual_wire)
		frames *= 2;

	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};
	int err;

	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);
}

615 616 617 618 619 620
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);
}

621
static void handle_out_packet(struct amdtp_stream *s, unsigned int syt)
622 623
{
	__be32 *buffer;
624
	unsigned int data_blocks, payload_length;
625 626
	struct snd_pcm_substream *pcm;

627 628 629
	if (s->packet_index < 0)
		return;

630
	/* this module generate empty packet for 'no data' */
631
	if (!(s->flags & CIP_BLOCKING) || (syt != CIP_SYT_NO_INFO))
632
		data_blocks = calculate_data_blocks(s);
633 634
	else
		data_blocks = 0;
635

636
	buffer = s->buffer.packets[s->packet_index].buffer;
637
	buffer[0] = cpu_to_be32(ACCESS_ONCE(s->source_node_id_field) |
638
				(s->data_block_quadlets << AMDTP_DBS_SHIFT) |
639 640
				s->data_block_counter);
	buffer[1] = cpu_to_be32(CIP_EOH | CIP_FMT_AM | AMDTP_FDF_AM824 |
641
				(s->sfc << CIP_FDF_SFC_SHIFT) | syt);
642 643 644 645 646 647 648 649 650 651 652 653
	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;

654 655
	payload_length = 8 + data_blocks * 4 * s->data_block_quadlets;
	if (queue_out_packet(s, payload_length, false) < 0) {
656
		s->packet_index = -1;
657
		amdtp_stream_pcm_abort(s);
658 659
		return;
	}
660

661
	if (pcm)
662
		update_pcm_pointers(s, pcm, data_blocks);
663 664
}

665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722
static void handle_in_packet(struct amdtp_stream *s,
			     unsigned int payload_quadlets,
			     __be32 *buffer)
{
	u32 cip_header[2];
	unsigned int data_blocks, data_block_quadlets, data_block_counter;
	struct snd_pcm_substream *pcm = NULL;

	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'.
	 * For convinience, also check FMT field is AM824 or not.
	 */
	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;
		}

		data_blocks = (payload_quadlets - 2) / data_block_quadlets;
	}

	/* Check data block counter continuity */
	data_block_counter = cip_header[0] & AMDTP_DBC_MASK;
	if (data_block_counter != s->data_block_counter) {
		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);
723 724 725

		if (s->midi_ports)
			amdtp_pull_midi(s, buffer, data_blocks);
726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741
	}

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

742 743 744
static void out_stream_callback(struct fw_iso_context *context, u32 cycle,
				size_t header_length, void *header,
				void *private_data)
745
{
746
	struct amdtp_stream *s = private_data;
747
	unsigned int i, syt, packets = header_length / 4;
748 749 750 751 752 753 754 755

	/*
	 * 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;

756 757 758 759
	for (i = 0; i < packets; ++i) {
		syt = calculate_syt(s, ++cycle);
		handle_out_packet(s, syt);
	}
760
	fw_iso_context_queue_flush(s->context);
761 762
}

763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787
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;
	unsigned int p, packets, payload_quadlets;
	__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)
			return;
		buffer = s->buffer.packets[s->packet_index].buffer;

		/* 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);
	}

	fw_iso_context_queue_flush(s->context);
}

788
/**
789 790
 * amdtp_stream_start - start transferring packets
 * @s: the AMDTP stream to start
791 792 793 794
 * @channel: the isochronous channel on the bus
 * @speed: firewire speed code
 *
 * The stream cannot be started until it has been configured with
795 796
 * amdtp_stream_set_parameters() and it must be started before any PCM or MIDI
 * device can be started.
797
 */
798
int amdtp_stream_start(struct amdtp_stream *s, int channel, int speed)
799 800 801 802 803 804 805 806 807 808 809 810 811
{
	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 },
	};
812 813 814 815
	unsigned int header_size;
	enum dma_data_direction dir;
	fw_iso_callback_t cb;
	int type, err;
816 817 818

	mutex_lock(&s->mutex);

819
	if (WARN_ON(amdtp_stream_running(s) ||
820
		    (s->data_block_quadlets < 1))) {
821 822 823 824
		err = -EBADFD;
		goto err_unlock;
	}

825
	s->data_block_counter = 0;
826 827 828 829
	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;

830 831 832 833 834 835 836 837 838 839 840 841
	/* initialize packet buffer */
	if (s->direction == AMDTP_IN_STREAM) {
		dir = DMA_FROM_DEVICE;
		type = FW_ISO_CONTEXT_RECEIVE;
		header_size = IN_PACKET_HEADER_SIZE;
		cb = in_stream_callback;
	} else {
		dir = DMA_TO_DEVICE;
		type = FW_ISO_CONTEXT_TRANSMIT;
		header_size = OUT_PACKET_HEADER_SIZE;
		cb = out_stream_callback;
	}
842
	err = iso_packets_buffer_init(&s->buffer, s->unit, QUEUE_LENGTH,
843
				      amdtp_stream_get_max_payload(s), dir);
844 845 846 847
	if (err < 0)
		goto err_unlock;

	s->context = fw_iso_context_create(fw_parent_device(s->unit)->card,
848 849
					   type, channel, speed, header_size,
					   cb, s);
850 851 852 853
	if (IS_ERR(s->context)) {
		err = PTR_ERR(s->context);
		if (err == -EBUSY)
			dev_err(&s->unit->device,
854
				"no free stream on this controller\n");
855 856 857
		goto err_buffer;
	}

858
	amdtp_stream_update(s);
859

860
	s->packet_index = 0;
861
	do {
862 863 864 865
		if (s->direction == AMDTP_IN_STREAM)
			err = queue_in_packet(s);
		else
			err = queue_out_packet(s, 0, true);
866 867 868
		if (err < 0)
			goto err_context;
	} while (s->packet_index > 0);
869

870 871 872
	/* NOTE: TAG1 matches CIP. This just affects in stream. */
	err = fw_iso_context_start(s->context, -1, 0,
				   FW_ISO_CONTEXT_MATCH_TAG1);
873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889
	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;
}
890
EXPORT_SYMBOL(amdtp_stream_start);
891

892
/**
893 894
 * amdtp_stream_pcm_pointer - get the PCM buffer position
 * @s: the AMDTP stream that transports the PCM data
895 896 897
 *
 * Returns the current buffer position, in frames.
 */
898
unsigned long amdtp_stream_pcm_pointer(struct amdtp_stream *s)
899
{
900 901 902 903 904
	/* this optimization is allowed to be racy */
	if (s->pointer_flush)
		fw_iso_context_flush_completions(s->context);
	else
		s->pointer_flush = true;
905 906 907

	return ACCESS_ONCE(s->pcm_buffer_pointer);
}
908
EXPORT_SYMBOL(amdtp_stream_pcm_pointer);
909

910
/**
911 912
 * amdtp_stream_update - update the stream after a bus reset
 * @s: the AMDTP stream
913
 */
914
void amdtp_stream_update(struct amdtp_stream *s)
915 916 917 918
{
	ACCESS_ONCE(s->source_node_id_field) =
		(fw_parent_device(s->unit)->card->node_id & 0x3f) << 24;
}
919
EXPORT_SYMBOL(amdtp_stream_update);
920 921

/**
922 923
 * amdtp_stream_stop - stop sending packets
 * @s: the AMDTP stream to stop
924 925 926 927
 *
 * All PCM and MIDI devices of the stream must be stopped before the stream
 * itself can be stopped.
 */
928
void amdtp_stream_stop(struct amdtp_stream *s)
929 930 931
{
	mutex_lock(&s->mutex);

932
	if (!amdtp_stream_running(s)) {
933 934 935 936
		mutex_unlock(&s->mutex);
		return;
	}

937
	tasklet_kill(&s->period_tasklet);
938 939 940 941 942 943 944
	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);

	mutex_unlock(&s->mutex);
}
945
EXPORT_SYMBOL(amdtp_stream_stop);
946 947

/**
948
 * amdtp_stream_pcm_abort - abort the running PCM device
949 950 951 952 953
 * @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.
 */
954
void amdtp_stream_pcm_abort(struct amdtp_stream *s)
955 956 957 958 959 960 961 962 963 964 965
{
	struct snd_pcm_substream *pcm;

	pcm = ACCESS_ONCE(s->pcm);
	if (pcm) {
		snd_pcm_stream_lock_irq(pcm);
		if (snd_pcm_running(pcm))
			snd_pcm_stop(pcm, SNDRV_PCM_STATE_XRUN);
		snd_pcm_stream_unlock_irq(pcm);
	}
}
966
EXPORT_SYMBOL(amdtp_stream_pcm_abort);