// SPDX-License-Identifier: GPL-2.0
// ff-protocol-latter - a part of driver for RME Fireface series
//
// Copyright (c) 2019 Takashi Sakamoto
//
// Licensed under the terms of the GNU General Public License, version 2.

#include <linux/delay.h>

#include "ff.h"

#define LATTER_STF              0xffff00000004ULL
#define LATTER_ISOC_CHANNELS    0xffff00000008ULL
#define LATTER_ISOC_START       0xffff0000000cULL
#define LATTER_FETCH_MODE       0xffff00000010ULL
#define LATTER_SYNC_STATUS      0x0000801c0000ULL

// 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 const struct {
                unsigned int rate;
                u32 flag;
        } *rate_entry, rate_entries[] = {
                { 32000,        0x00, },
                { 44100,        0x01, },
                { 48000,        0x02, },
                { 64000,        0x04, },
                { 88200,        0x05, },
                { 96000,        0x06, },
                { 128000,       0x08, },
                { 176400,       0x09, },
                { 192000,       0x0a, },
        };
        static const struct {
                enum snd_ff_clock_src src;
                u32 flag;
        } *clk_entry, *clk_entries, ucx_clk_entries[] = {
                { SND_FF_CLOCK_SRC_SPDIF,       0x00000200, },
                { SND_FF_CLOCK_SRC_ADAT1,       0x00000400, },
                { SND_FF_CLOCK_SRC_WORD,        0x00000600, },
                { SND_FF_CLOCK_SRC_INTERNAL,    0x00000e00, },
        }, ufx_ff802_clk_entries[] = {
                { SND_FF_CLOCK_SRC_WORD,        0x00000200, },
                { SND_FF_CLOCK_SRC_SPDIF,       0x00000400, },
                { SND_FF_CLOCK_SRC_ADAT1,       0x00000600, },
                { SND_FF_CLOCK_SRC_ADAT2,       0x00000800, },
                { SND_FF_CLOCK_SRC_INTERNAL,    0x00000e00, },
        };
        u32 rate_bits;
        unsigned int clk_entry_count;
        int i;

        if (unit_version == SND_FF_UNIT_VERSION_UCX) {
                rate_bits = (data & 0x0f000000) >> 24;
                clk_entries = ucx_clk_entries;
                clk_entry_count = ARRAY_SIZE(ucx_clk_entries);
        } else {
                rate_bits = (data & 0xf0000000) >> 28;
                clk_entries = ufx_ff802_clk_entries;
                clk_entry_count = ARRAY_SIZE(ufx_ff802_clk_entries);
        }

        for (i = 0; i < ARRAY_SIZE(rate_entries); ++i) {
                rate_entry = rate_entries + i;
                if (rate_bits == rate_entry->flag) {
                        *rate = rate_entry->rate;
                        break;
                }
        }
        if (i == ARRAY_SIZE(rate_entries))
                return -EIO;

        for (i = 0; i < clk_entry_count; ++i) {
                clk_entry = clk_entries + i;
                if ((data & 0x000e00) == clk_entry->flag) {
                        *src = clk_entry->src;
                        break;
                }
        }
        if (i == clk_entry_count)
                return -EIO;

        return 0;
}

static int latter_get_clock(struct snd_ff *ff, unsigned int *rate,
                           enum snd_ff_clock_src *src)
{
        __le32 reg;
        u32 data;
        int err;

        err = snd_fw_transaction(ff->unit, TCODE_READ_QUADLET_REQUEST,
                                 LATTER_SYNC_STATUS, &reg, sizeof(reg), 0);
        if (err < 0)
                return err;
        data = le32_to_cpu(reg);

        return parse_clock_bits(data, rate, src, ff->unit_version);
}

static int latter_switch_fetching_mode(struct snd_ff *ff, bool enable)
{
        u32 data;
        __le32 reg;

        if (enable)
                data = 0x00000000;
        else
                data = 0xffffffff;
        reg = cpu_to_le32(data);

        return snd_fw_transaction(ff->unit, TCODE_WRITE_QUADLET_REQUEST,
                                  LATTER_FETCH_MODE, &reg, sizeof(reg), 0);
}

static int latter_allocate_resources(struct snd_ff *ff, unsigned int rate)
{
        enum snd_ff_stream_mode mode;
        unsigned int code;
        __le32 reg;
        unsigned int count;
        int i;
        int err;

        // Set the number of data blocks transferred in a second.
        if (rate % 48000 == 0)
                code = 0x04;
        else if (rate % 44100 == 0)
                code = 0x02;
        else if (rate % 32000 == 0)
                code = 0x00;
        else
                return -EINVAL;

        if (rate >= 64000 && rate < 128000)
                code |= 0x08;
        else if (rate >= 128000)
                code |= 0x10;

        reg = cpu_to_le32(code);
        err = snd_fw_transaction(ff->unit, TCODE_WRITE_QUADLET_REQUEST,
                                 LATTER_STF, &reg, sizeof(reg), 0);
        if (err < 0)
                return err;

        // Confirm to shift transmission clock.
        count = 0;
        while (count++ < 10) {
                unsigned int curr_rate;
                enum snd_ff_clock_src src;

                err = latter_get_clock(ff, &curr_rate, &src);
                if (err < 0)
                        return err;

                if (curr_rate == rate)
                        break;
        }
        if (count > 10)
                return -ETIMEDOUT;

        for (i = 0; i < ARRAY_SIZE(amdtp_rate_table); ++i) {
                if (rate == amdtp_rate_table[i])
                        break;
        }
        if (i == ARRAY_SIZE(amdtp_rate_table))
                return -EINVAL;

        err = snd_ff_stream_get_multiplier_mode(i, &mode);
        if (err < 0)
                return err;

        // Keep resources for in-stream.
        ff->tx_resources.channels_mask = 0x00000000000000ffuLL;
        err = fw_iso_resources_allocate(&ff->tx_resources,
                        amdtp_stream_get_max_payload(&ff->tx_stream),
                        fw_parent_device(ff->unit)->max_speed);
        if (err < 0)
                return err;

        // Keep resources for out-stream.
        ff->rx_resources.channels_mask = 0x00000000000000ffuLL;
        err = fw_iso_resources_allocate(&ff->rx_resources,
                        amdtp_stream_get_max_payload(&ff->rx_stream),
                        fw_parent_device(ff->unit)->max_speed);
        if (err < 0)
                fw_iso_resources_free(&ff->tx_resources);

        return err;
}

static int latter_begin_session(struct snd_ff *ff, unsigned int rate)
{
        unsigned int generation = ff->rx_resources.generation;
        unsigned int flag;
        u32 data;
        __le32 reg;
        int err;

        if (ff->unit_version == SND_FF_UNIT_VERSION_UCX) {
                // For Fireface UCX. Always use the maximum number of data
                // channels in data block of packet.
                if (rate >= 32000 && rate <= 48000)
                        flag = 0x92;
                else if (rate >= 64000 && rate <= 96000)
                        flag = 0x8e;
                else if (rate >= 128000 && rate <= 192000)
                        flag = 0x8c;
                else
                        return -EINVAL;
        } else {
                // For Fireface UFX and 802. Due to bandwidth limitation on
                // IEEE 1394a (400 Mbps), Analog 1-12 and AES are available
                // without any ADAT at quadruple speed.
                if (rate >= 32000 && rate <= 48000)
                        flag = 0x9e;
                else if (rate >= 64000 && rate <= 96000)
                        flag = 0x96;
                else if (rate >= 128000 && rate <= 192000)
                        flag = 0x8e;
                else
                        return -EINVAL;
        }

        if (generation != fw_parent_device(ff->unit)->card->generation) {
                err = fw_iso_resources_update(&ff->tx_resources);
                if (err < 0)
                        return err;

                err = fw_iso_resources_update(&ff->rx_resources);
                if (err < 0)
                        return err;
        }

        data = (ff->tx_resources.channel << 8) | ff->rx_resources.channel;
        reg = cpu_to_le32(data);
        err = snd_fw_transaction(ff->unit, TCODE_WRITE_QUADLET_REQUEST,
                                 LATTER_ISOC_CHANNELS, &reg, sizeof(reg), 0);
        if (err < 0)
                return err;

        reg = cpu_to_le32(flag);
        return snd_fw_transaction(ff->unit, TCODE_WRITE_QUADLET_REQUEST,
                                  LATTER_ISOC_START, &reg, sizeof(reg), 0);
}

static void latter_finish_session(struct snd_ff *ff)
{
        __le32 reg;

        reg = cpu_to_le32(0x00000000);
        snd_fw_transaction(ff->unit, TCODE_WRITE_QUADLET_REQUEST,
                           LATTER_ISOC_START, &reg, sizeof(reg), 0);
}

static void latter_dump_status(struct snd_ff *ff, struct snd_info_buffer *buffer)
{
        static const struct {
                char *const label;
                u32 locked_mask;
                u32 synced_mask;
        } *clk_entry, *clk_entries, ucx_clk_entries[] = {
                { "S/PDIF",     0x00000001, 0x00000010, },
                { "ADAT",       0x00000002, 0x00000020, },
                { "WDClk",      0x00000004, 0x00000040, },
        }, ufx_ff802_clk_entries[] = {
                { "WDClk",      0x00000001, 0x00000010, },
                { "AES/EBU",    0x00000002, 0x00000020, },
                { "ADAT-A",     0x00000004, 0x00000040, },
                { "ADAT-B",     0x00000008, 0x00000080, },
        };
        __le32 reg;
        u32 data;
        unsigned int rate;
        enum snd_ff_clock_src src;
        const char *label;
        unsigned int clk_entry_count;
        int i;
        int err;

        err = snd_fw_transaction(ff->unit, TCODE_READ_QUADLET_REQUEST,
                                 LATTER_SYNC_STATUS, &reg, sizeof(reg), 0);
        if (err < 0)
                return;
        data = le32_to_cpu(reg);

        snd_iprintf(buffer, "External source detection:\n");

        if (ff->unit_version == SND_FF_UNIT_VERSION_UCX) {
                clk_entries = ucx_clk_entries;
                clk_entry_count = ARRAY_SIZE(ucx_clk_entries);
        } else {
                clk_entries = ufx_ff802_clk_entries;
                clk_entry_count = ARRAY_SIZE(ufx_ff802_clk_entries);
        }

        for (i = 0; i < clk_entry_count; ++i) {
                clk_entry = clk_entries + i;
                snd_iprintf(buffer, "%s: ", clk_entry->label);
                if (data & clk_entry->locked_mask) {
                        if (data & clk_entry->synced_mask)
                                snd_iprintf(buffer, "sync\n");
                        else
                                snd_iprintf(buffer, "lock\n");
                } else {
                        snd_iprintf(buffer, "none\n");
                }
        }

        err = parse_clock_bits(data, &rate, &src, ff->unit_version);
        if (err < 0)
                return;
        label = snd_ff_proc_get_clk_label(src);
        if (!label)
                return;

        snd_iprintf(buffer, "Referred clock: %s %d\n", label, rate);
}

// 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,
                                   __le32 *buf, size_t length)
{
        u32 data = le32_to_cpu(*buf);
        unsigned int index = (data & 0x000000f0) >> 4;
        u8 byte[3];
        struct snd_rawmidi_substream *substream;
        unsigned int len;

        if (index >= ff->spec->midi_in_ports)
                return;

        switch (data & 0x0000000f) {
        case 0x00000008:
        case 0x00000009:
        case 0x0000000a:
        case 0x0000000b:
        case 0x0000000e:
                len = 3;
                break;
        case 0x0000000c:
        case 0x0000000d:
                len = 2;
                break;
        default:
                len = data & 0x00000003;
                if (len == 0)
                        len = 3;
                break;
        }

        byte[0] = (data & 0x0000ff00) >> 8;
        byte[1] = (data & 0x00ff0000) >> 16;
        byte[2] = (data & 0xff000000) >> 24;

        substream = READ_ONCE(ff->tx_midi_substreams[index]);
        if (substream)
                snd_rawmidi_receive(substream, byte, len);
}

/*
 * 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)
{
        switch (status) {
        case 0xf6:      /* Tune request. */
        case 0xf8:      /* Timing clock. */
        case 0xfa:      /* Start. */
        case 0xfb:      /* Continue. */
        case 0xfc:      /* Stop. */
        case 0xfe:      /* Active sensing. */
        case 0xff:      /* System reset. */
                return 1;
        case 0xf1:      /* MIDI time code quarter frame. */
        case 0xf3:      /* Song select. */
                return 2;
        case 0xf2:      /* Song position pointer. */
                return 3;
        case 0xf0:      /* Exclusive. */
                return 0;
        case 0xf7:      /* End of exclusive. */
                break;
        case 0xf4:      /* Undefined. */
        case 0xf5:      /* Undefined. */
        case 0xf9:      /* Undefined. */
        case 0xfd:      /* Undefined. */
                break;
        default:
                switch (status & 0xf0) {
                case 0x80:      /* Note on. */
                case 0x90:      /* Note off. */
                case 0xa0:      /* Polyphonic key pressure. */
                case 0xb0:      /* Control change and Mode change. */
                case 0xe0:      /* Pitch bend change. */
                        return 3;
                case 0xc0:      /* Program change. */
                case 0xd0:      /* Channel pressure. */
                        return 2;
                default:
                break;
                }
        break;
        }

        return -EINVAL;
}

static int latter_fill_midi_msg(struct snd_ff *ff,
                                struct snd_rawmidi_substream *substream,
                                unsigned int port)
{
        u32 data = {0};
        u8 *buf = (u8 *)&data;
        int consumed;

        buf[0] = port << 4;
        consumed = snd_rawmidi_transmit_peek(substream, buf + 1, 3);
        if (consumed <= 0)
                return consumed;

        if (!ff->on_sysex[port]) {
                if (buf[1] != 0xf0) {
                        if (consumed < calculate_message_bytes(buf[1]))
                                return 0;
                } else {
                        // The beginning of exclusives.
                        ff->on_sysex[port] = true;
                }

                buf[0] |= consumed;
        } else {
                if (buf[1] != 0xf7) {
                        if (buf[2] == 0xf7 || buf[3] == 0xf7) {
                                // Transfer end code at next time.
                                consumed -= 1;
                        }

                        buf[0] |= consumed;
                } else {
                        // The end of exclusives.
                        ff->on_sysex[port] = false;
                        consumed = 1;
                        buf[0] |= 0x0f;
                }
        }

        ff->msg_buf[port][0] = cpu_to_le32(data);
        ff->rx_bytes[port] = consumed;

        return 1;
}

const struct snd_ff_protocol snd_ff_protocol_latter = {
        .handle_midi_msg        = latter_handle_midi_msg,
        .fill_midi_msg          = latter_fill_midi_msg,
        .get_clock              = latter_get_clock,
        .switch_fetching_mode   = latter_switch_fetching_mode,
        .allocate_resources     = latter_allocate_resources,
        .begin_session          = latter_begin_session,
        .finish_session         = latter_finish_session,
        .dump_status            = latter_dump_status,
};