/*
* 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 <linux/sched.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/rawmidi.h>
#include "amdtp.h"
#define TICKS_PER_CYCLE 3072
#define CYCLES_PER_SECOND 8000
#define TICKS_PER_SECOND (TICKS_PER_CYCLE * CYCLES_PER_SECOND)
/*
* 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
/*
* 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
#define TRANSFER_DELAY_TICKS 0x2e00 /* 479.17 microseconds */
/* isochronous header parameters */
#define ISO_DATA_LENGTH_SHIFT 16
#define TAG_CIP 1
/* common isochronous packet header parameters */
#define CIP_EOH (1u << 31)
#define CIP_EOH_MASK 0x80000000
#define CIP_FMT_AM (0x10 << 24)
#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))
#define AMDTP_FDF_NO_DATA 0xff
#define AMDTP_DBS_MASK 0x00ff0000
#define AMDTP_DBS_SHIFT 16
#define AMDTP_DBC_MASK 0x000000ff
/* TODO: make these configurable */
#define INTERRUPT_INTERVAL 16
#define QUEUE_LENGTH 48
#define IN_PACKET_HEADER_SIZE 4
#define OUT_PACKET_HEADER_SIZE 0
static void pcm_period_tasklet(unsigned long data);
/**
* amdtp_stream_init - initialize an AMDTP stream structure
* @s: the AMDTP stream to initialize
* @unit: the target of the stream
* @dir: the direction of stream
* @flags: the packet transmission method to use
*/
int amdtp_stream_init(struct amdtp_stream *s, struct fw_unit *unit,
enum amdtp_stream_direction dir, enum cip_flags flags)
{
s->unit = unit;
s->direction = dir;
s->flags = flags;
s->context = ERR_PTR(-1);
mutex_init(&s->mutex);
tasklet_init(&s->period_tasklet, pcm_period_tasklet, (unsigned long)s);
s->packet_index = 0;
init_waitqueue_head(&s->callback_wait);
s->callbacked = false;
s->sync_slave = NULL;
return 0;
}
EXPORT_SYMBOL(amdtp_stream_init);
/**
* amdtp_stream_destroy - free stream resources
* @s: the AMDTP stream to destroy
*/
void amdtp_stream_destroy(struct amdtp_stream *s)
{
WARN_ON(amdtp_stream_running(s));
mutex_destroy(&s->mutex);
}
EXPORT_SYMBOL(amdtp_stream_destroy);
const unsigned int amdtp_syt_intervals[CIP_SFC_COUNT] = {
[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);
const unsigned int amdtp_rate_table[CIP_SFC_COUNT] = {
[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);
/**
* 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);
/**
* amdtp_stream_set_parameters - set stream parameters
* @s: the AMDTP stream to configure
* @rate: the sample rate
* @pcm_channels: the number of PCM samples in each data block, to be encoded