sys/dev/firewire/fwisound.h

root/sys/dev/firewire/fwisound.h
/*
 * Copyright (c) 2026 Abdelkader Boudih <freebsd@seuros.com>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#ifndef _DEV_FIREWIRE_FWISOUND_H_
#define _DEV_FIREWIRE_FWISOUND_H_

#include <dev/firewire/fwcam.h>

/* Protocol reverse-engineered by Clemens Ladisch (Linux isight-firmware). */
#define FWISOUND_SPEC_ID        APPLE_FW_OUI
#define FWISOUND_VERSION        0x000010        /* SW_ISIGHT_AUDIO */

#define APPLE_FW_OUI            0x000a27

/* Audio register offsets from audio_base */
#define FWISOUND_REG_AUDIO_ENABLE       0x000   /* bit31 = enable streaming */
#define FWISOUND_REG_DEF_AUDIO_GAIN     0x204
#define FWISOUND_REG_GAIN_RAW_START     0x210
#define FWISOUND_REG_GAIN_RAW_END       0x214
#define FWISOUND_REG_GAIN_DB_START      0x218
#define FWISOUND_REG_GAIN_DB_END        0x21c
#define FWISOUND_REG_SAMPLE_RATE_INQ    0x280
#define FWISOUND_REG_ISO_TX_CONFIG      0x300   /* bits[19:16]=speed, [3:0]=ch*/
#define FWISOUND_REG_SAMPLE_RATE        0x400   /* bit31 = 1 → 48000 Hz */
#define FWISOUND_REG_GAIN               0x500
#define FWISOUND_REG_MUTE               0x504

/* REG_AUDIO_ENABLE / REG_SAMPLE_RATE bit */
#define FWISOUND_AUDIO_ENABLE           (1u << 31)
#define FWISOUND_RATE_48000             (1u << 31)

#define FWISOUND_MAX_SAMPLES    475             /* max samples per ISO packet */
#define FWISOUND_SIGNATURE      0x73676874u     /* "sght" */

/* Apple FireWire audio ISO payload. */
struct fwisound_payload {
        uint32_t        sample_count;           /* samples in this packet */
        uint32_t        signature;              /* 0x73676874 = "sght" */
        uint32_t        sample_total;           /* running total (drop detect)*/
        uint32_t        reserved;
        int16_t         samples[2 * FWISOUND_MAX_SAMPLES]; /* stereo S16BE */
};

/* ISO DMA parameters */
#define FWISOUND_ISO_CHANNEL    1
#define FWISOUND_ISO_NCHUNK     64
#define FWISOUND_ISO_PKTSIZE    2048            /* MCLBYTES */

/* Driver states */
#define FWISOUND_STATE_IDLE     0
#define FWISOUND_STATE_PROBED   1
#define FWISOUND_STATE_STREAMING 2
#define FWISOUND_STATE_DETACHING 3

#ifdef _KERNEL

#include <dev/sound/pcm/sound.h>

struct fwisound_chan {
        struct fwisound_softc   *sc;
        struct pcm_channel      *pcm_chan;
        struct snd_dbuf         *buf;
        struct pcmchan_caps      caps;
        uint32_t                 fmts[2];
        uint32_t                 hw_ptr;        /* ring write offset (bytes) */
        int                      running;
};

struct fwisound_softc {
        struct firewire_dev_comm fd;    /* MUST BE FIRST */
        struct mtx               mtx;
        device_t                 dev;
        device_t                 pcm_dev;

        struct fw_device        *fwdev;
        uint16_t                 cmd_hi;        /* always 0xffff */
        uint32_t                 cmd_lo;        /* 0xf0000000|(audio_base<<2) */

        struct task              probe_task;
        struct task              start_task;    /* deferred iso_start */
        struct task              stop_task;     /* deferred iso_stop */

        /* ISO streaming */
        int                      dma_ch;        /* -1 = not open */
        int                      iso_active;    /* iso_input running */
        uint8_t                  iso_channel;

        /* PCM channel back-reference */
        struct fwisound_chan    *chan;

        /* Sample drop detection */
        uint32_t                 sample_total;

        /* Gain range (read from camera during probe) */
        int32_t                  gain_raw_min;
        int32_t                  gain_raw_max;

        int                      state;
        int                      dropped;
};

#define FWISOUND_LOCK(sc)       mtx_lock(&(sc)->mtx)
#define FWISOUND_UNLOCK(sc)     mtx_unlock(&(sc)->mtx)

int     fwisound_iso_start(struct fwisound_softc *);
void    fwisound_iso_stop(struct fwisound_softc *);

#endif /* _KERNEL */

#endif /* _DEV_FIREWIRE_FWISOUND_H_ */
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