ff-protocol-latter.c | Explore in Territory

// SPDX-License-Identifier: GPL-2.0
// ff-protocol-latter.c - a part of driver for RME Fireface series
//
// Copyright (c) 2019 Takashi Sakamoto

#include <linux/delay.h>

#include "ff.h"

#define LATTER_STF …
#define LATTER_ISOC_CHANNELS …
#define LATTER_ISOC_START …
#define LATTER_FETCH_MODE …
#define LATTER_SYNC_STATUS …

// The content of sync status register differs between models.
//
// Fireface UCX:
//  0xf0000000: (unidentified)
//  0x0f000000: effective rate of sampling clock
//  0x00f00000: detected rate of word clock on BNC interface
//  0x000f0000: detected rate of ADAT or S/PDIF on optical interface
//  0x0000f000: detected rate of S/PDIF on coaxial interface
//  0x00000e00: effective source of sampling clock
//    0x00000e00: Internal
//    0x00000800: (unidentified)
//    0x00000600: Word clock on BNC interface
//    0x00000400: ADAT on optical interface
//    0x00000200: S/PDIF on coaxial or optical interface
//  0x00000100: Optical interface is used for ADAT signal
//  0x00000080: (unidentified)
//  0x00000040: Synchronized to word clock on BNC interface
//  0x00000020: Synchronized to ADAT or S/PDIF on optical interface
//  0x00000010: Synchronized to S/PDIF on coaxial interface
//  0x00000008: (unidentified)
//  0x00000004: Lock word clock on BNC interface
//  0x00000002: Lock ADAT or S/PDIF on optical interface
//  0x00000001: Lock S/PDIF on coaxial interface
//
// Fireface 802 (and perhaps UFX):
//   0xf0000000: effective rate of sampling clock
//   0x0f000000: detected rate of ADAT-B on 2nd optical interface
//   0x00f00000: detected rate of ADAT-A on 1st optical interface
//   0x000f0000: detected rate of AES/EBU on XLR or coaxial interface
//   0x0000f000: detected rate of word clock on BNC interface
//   0x00000e00: effective source of sampling clock
//     0x00000e00: internal
//     0x00000800: ADAT-B
//     0x00000600: ADAT-A
//     0x00000400: AES/EBU
//     0x00000200: Word clock
//   0x00000080: Synchronized to ADAT-B on 2nd optical interface
//   0x00000040: Synchronized to ADAT-A on 1st optical interface
//   0x00000020: Synchronized to AES/EBU on XLR or 2nd optical interface
//   0x00000010: Synchronized to word clock on BNC interface
//   0x00000008: Lock ADAT-B on 2nd optical interface
//   0x00000004: Lock ADAT-A on 1st optical interface
//   0x00000002: Lock AES/EBU on XLR or 2nd optical interface
//   0x00000001: Lock word clock on BNC interface
//
// The pattern for rate bits:
//   0x00: 32.0 kHz
//   0x01: 44.1 kHz
//   0x02: 48.0 kHz
//   0x04: 64.0 kHz
//   0x05: 88.2 kHz
//   0x06: 96.0 kHz
//   0x08: 128.0 kHz
//   0x09: 176.4 kHz
//   0x0a: 192.0 kHz
static int parse_clock_bits(u32 data, unsigned int *rate,
			    enum snd_ff_clock_src *src,
			    enum snd_ff_unit_version unit_version)
{ … }

static int latter_get_clock(struct snd_ff *ff, unsigned int *rate,
			   enum snd_ff_clock_src *src)
{ … }

static int latter_switch_fetching_mode(struct snd_ff *ff, bool enable)
{ … }

static int latter_allocate_resources(struct snd_ff *ff, unsigned int rate)
{ … }

static int latter_begin_session(struct snd_ff *ff, unsigned int rate)
{ … }

static void latter_finish_session(struct snd_ff *ff)
{ … }

static void latter_dump_status(struct snd_ff *ff, struct snd_info_buffer *buffer)
{ … }

// NOTE: transactions are transferred within 0x00-0x7f in allocated range of
// address. This seems to be for check of discontinuity in receiver side.
//
// Like Fireface 400, drivers can select one of 4 options for lower 4 bytes of
// destination address by bit flags in quadlet register (little endian) at
// 0x'ffff'0000'0014:
//
// bit flags: offset of destination address
// - 0x00002000: 0x'....'....'0000'0000
// - 0x00004000: 0x'....'....'0000'0080
// - 0x00008000: 0x'....'....'0000'0100
// - 0x00010000: 0x'....'....'0000'0180
//
// Drivers can suppress the device to transfer asynchronous transactions by
// clear these bit flags.
//
// Actually, the register is write-only and includes the other settings such as
// input attenuation. This driver allocates for the first option
// (0x'....'....'0000'0000) and expects userspace application to configure the
// register for it.
static void latter_handle_midi_msg(struct snd_ff *ff, unsigned int offset, const __le32 *buf,
				   size_t length, u32 tstamp)
{ … }

/*
 * When return minus value, given argument is not MIDI status.
 * When return 0, given argument is a beginning of system exclusive.
 * When return the others, given argument is MIDI data.
 */
static inline int calculate_message_bytes(u8 status)
{ … }

static int latter_fill_midi_msg(struct snd_ff *ff,
				struct snd_rawmidi_substream *substream,
				unsigned int port)
{ … }

const struct snd_ff_protocol snd_ff_protocol_latter = …;
linux/sound/firewire/fireface/ff-protocol-latter.c
