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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>
#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 */
#define TAG_CIP 1
#define CIP_EOH (1u << 31)
#define CIP_FMT_AM (0x10 << 24)
#define AMDTP_FDF_AM824 (0 << 19)
#define AMDTP_FDF_SFC_SHIFT 16
/* TODO: make these configurable */
#define INTERRUPT_INTERVAL 16
#define QUEUE_LENGTH 48
/**
* amdtp_out_stream_init - initialize an AMDTP output stream structure
* @s: the AMDTP output stream to initialize
* @unit: the target of the stream
* @flags: the packet transmission method to use
*/
int amdtp_out_stream_init(struct amdtp_out_stream *s, struct fw_unit *unit,
enum cip_out_flags flags)
{
if (flags != CIP_NONBLOCKING)
return -EINVAL;
s->unit = fw_unit_get(unit);
s->flags = flags;
s->context = ERR_PTR(-1);
mutex_init(&s->mutex);
s->packet_index = 0;
return 0;
}
EXPORT_SYMBOL(amdtp_out_stream_init);
/**
* amdtp_out_stream_destroy - free stream resources
* @s: the AMDTP output stream to destroy
*/
void amdtp_out_stream_destroy(struct amdtp_out_stream *s)
{
WARN_ON(!IS_ERR(s->context));
mutex_destroy(&s->mutex);
fw_unit_put(s->unit);
}
EXPORT_SYMBOL(amdtp_out_stream_destroy);
/**
* amdtp_out_stream_set_rate - set the sample rate
* @s: the AMDTP output stream to configure
* @rate: the sample rate
*
* The sample rate must be set before the stream is started, and must not be
* changed while the stream is running.
*/
void amdtp_out_stream_set_rate(struct amdtp_out_stream *s, unsigned int rate)
{
static const struct {
unsigned int rate;
unsigned int syt_interval;
} rate_info[] = {
[CIP_SFC_32000] = { 32000, 8, },
[CIP_SFC_44100] = { 44100, 8, },
[CIP_SFC_48000] = { 48000, 8, },
[CIP_SFC_88200] = { 88200, 16, },
[CIP_SFC_96000] = { 96000, 16, },
[CIP_SFC_176400] = { 176400, 32, },
[CIP_SFC_192000] = { 192000, 32, },
};
unsigned int sfc;
if (WARN_ON(!IS_ERR(s->context)))
return;
for (sfc = 0; sfc < ARRAY_SIZE(rate_info); ++sfc)
if (rate_info[sfc].rate == rate) {
s->sfc = sfc;
s->syt_interval = rate_info[sfc].syt_interval;
return;
}
WARN_ON(1);
}
EXPORT_SYMBOL(amdtp_out_stream_set_rate);
/**
* amdtp_out_stream_get_max_payload - get the stream's packet size
* @s: the AMDTP output stream
*
* This function must not be called before the stream has been configured
* with amdtp_out_stream_set_hw_params(), amdtp_out_stream_set_pcm(), and
* amdtp_out_stream_set_midi().
*/
unsigned int amdtp_out_stream_get_max_payload(struct amdtp_out_stream *s)
{
static const unsigned int max_data_blocks[] = {
[CIP_SFC_32000] = 4,
[CIP_SFC_44100] = 6,
[CIP_SFC_48000] = 6,
[CIP_SFC_88200] = 12,
[CIP_SFC_96000] = 12,
[CIP_SFC_176400] = 23,
[CIP_SFC_192000] = 24,
};
s->data_block_quadlets = s->pcm_channels;
s->data_block_quadlets += DIV_ROUND_UP(s->midi_ports, 8);
return 8 + max_data_blocks[s->sfc] * 4 * s->data_block_quadlets;
}
EXPORT_SYMBOL(amdtp_out_stream_get_max_payload);
static void amdtp_write_s16(struct amdtp_out_stream *s,
struct snd_pcm_substream *pcm,
__be32 *buffer, unsigned int frames);
static void amdtp_write_s32(struct amdtp_out_stream *s,
struct snd_pcm_substream *pcm,
__be32 *buffer, unsigned int frames);
/**
* amdtp_out_stream_set_pcm_format - set the PCM format
* @s: the AMDTP output stream to configure
* @format: the format of the ALSA PCM device
*
* The sample format must be set before the stream is started, and must not be
* changed while the stream is running.
*/
void amdtp_out_stream_set_pcm_format(struct amdtp_out_stream *s,
snd_pcm_format_t format)
{
if (WARN_ON(!IS_ERR(s->context)))
return;
switch (format) {
default:
WARN_ON(1);
/* fall through */
case SNDRV_PCM_FORMAT_S16:
s->transfer_samples = amdtp_write_s16;
break;
case SNDRV_PCM_FORMAT_S32:
s->transfer_samples = amdtp_write_s32;
break;
}
}
EXPORT_SYMBOL(amdtp_out_stream_set_pcm_format);
static unsigned int calculate_data_blocks(struct amdtp_out_stream *s)
{
unsigned int phase, data_blocks;
if (!cip_sfc_is_base_44100(s->sfc)) {
/* 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;
}
static unsigned int calculate_syt(struct amdtp_out_stream *s,
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;
if (syt_offset < TICKS_PER_CYCLE) {
syt_offset += TRANSFER_DELAY_TICKS - TICKS_PER_CYCLE;
syt = (cycle + syt_offset / TICKS_PER_CYCLE) << 12;
syt += syt_offset % TICKS_PER_CYCLE;
return syt & 0xffff;
} else {
return 0xffff; /* no info */
}
}
static void amdtp_write_s32(struct amdtp_out_stream *s,
struct snd_pcm_substream *pcm,
__be32 *buffer, unsigned int frames)
{
struct snd_pcm_runtime *runtime = pcm
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