// SPDX-License-Identifier: GPL-2.0-only
//
// motu-register-dsp-message-parser.c - a part of driver for MOTU FireWire series
//
// Copyright (c) 2021 Takashi Sakamoto <o-takashi@sakamocchi.jp>

// Below models allow software to configure their DSP functions by asynchronous transaction
// to access their internal registers.
// * 828 mk2
// * 896hd
// * Traveler
// * 8 pre
// * Ultralite
// * 4 pre
// * Audio Express
//
// Additionally, isochronous packets from the above models include messages to notify state of
// DSP. The messages are two set of 3 byte data in 2nd and 3rd quadlet of data block. When user
// operates hardware components such as dial and switch, corresponding messages are transferred.
// The messages include Hardware metering and MIDI messages as well.

#include "motu.h"

#define MSG_FLAG_POS                    4
#define MSG_FLAG_TYPE_MASK              0xf8
#define MSG_FLAG_MIDI_MASK              0x01
#define MSG_FLAG_MODEL_SPECIFIC_MASK    0x06
#define   MSG_FLAG_8PRE                 0x00
#define   MSG_FLAG_ULTRALITE            0x04
#define   MSG_FLAG_TRAVELER             0x04
#define   MSG_FLAG_828MK2               0x04
#define   MSG_FLAG_896HD                0x04
#define   MSG_FLAG_4PRE                 0x05 // MIDI mask is in 8th byte.
#define   MSG_FLAG_AUDIOEXPRESS         0x05 // MIDI mask is in 8th byte.
#define MSG_FLAG_TYPE_SHIFT             3
#define MSG_VALUE_POS                   5
#define MSG_MIDI_BYTE_POS               6
#define MSG_METER_IDX_POS               7

// In 4 pre and Audio express, meter index is in 6th byte. MIDI flag is in 8th byte and MIDI byte
// is in 7th byte.
#define MSG_METER_IDX_POS_4PRE_AE       6
#define MSG_MIDI_BYTE_POS_4PRE_AE       7
#define MSG_FLAG_MIDI_POS_4PRE_AE       8

enum register_dsp_msg_type {
        // Used for messages with no information.
        INVALID = 0x00,
        MIXER_SELECT = 0x01,
        MIXER_SRC_GAIN = 0x02,
        MIXER_SRC_PAN = 0x03,
        MIXER_SRC_FLAG = 0x04,
        MIXER_OUTPUT_PAIRED_VOLUME = 0x05,
        MIXER_OUTPUT_PAIRED_FLAG = 0x06,
        MAIN_OUTPUT_PAIRED_VOLUME = 0x07,
        HP_OUTPUT_PAIRED_VOLUME = 0x08,
        HP_OUTPUT_PAIRED_ASSIGNMENT = 0x09,
        // Transferred by all models but the purpose is still unknown.
        UNKNOWN_0 = 0x0a,
        // Specific to 828mk2, 896hd, Traveler.
        UNKNOWN_2 = 0x0c,
        // Specific to 828mk2, Traveler, and 896hd (not functional).
        LINE_INPUT_BOOST = 0x0d,
        // Specific to 828mk2, Traveler, and 896hd (not functional).
        LINE_INPUT_NOMINAL_LEVEL = 0x0e,
        // Specific to Ultralite, 4 pre, Audio express, and 8 pre (not functional).
        INPUT_GAIN_AND_INVERT = 0x15,
        // Specific to 4 pre, and Audio express.
        INPUT_FLAG = 0x16,
        // Specific to 4 pre, and Audio express.
        MIXER_SRC_PAIRED_BALANCE = 0x17,
        // Specific to 4 pre, and Audio express.
        MIXER_SRC_PAIRED_WIDTH = 0x18,
        // Transferred by all models. This type of message interposes the series of the other
        // messages. The message delivers signal level up to 96.0 kHz. In 828mk2, 896hd, and
        // Traveler, one of physical outputs is selected for the message. The selection is done
        // by LSB one byte in asynchronous write quadlet transaction to 0x'ffff'f000'0b2c.
        METER = 0x1f,
};

#define EVENT_QUEUE_SIZE        16

struct msg_parser {
        spinlock_t lock;
        struct snd_firewire_motu_register_dsp_meter meter;
        bool meter_pos_quirk;

        struct snd_firewire_motu_register_dsp_parameter param;
        u8 prev_mixer_src_type;
        u8 mixer_ch;
        u8 mixer_src_ch;

        u8 input_ch;
        u8 prev_msg_type;

        u32 event_queue[EVENT_QUEUE_SIZE];
        unsigned int push_pos;
        unsigned int pull_pos;
};

int snd_motu_register_dsp_message_parser_new(struct snd_motu *motu)
{
        struct msg_parser *parser;
        parser = devm_kzalloc(&motu->card->card_dev, sizeof(*parser), GFP_KERNEL);
        if (!parser)
                return -ENOMEM;
        spin_lock_init(&parser->lock);
        if (motu->spec == &snd_motu_spec_4pre || motu->spec == &snd_motu_spec_audio_express)
                parser->meter_pos_quirk = true;
        motu->message_parser = parser;
        return 0;
}

int snd_motu_register_dsp_message_parser_init(struct snd_motu *motu)
{
        struct msg_parser *parser = motu->message_parser;

        parser->prev_mixer_src_type = INVALID;
        parser->mixer_ch = 0xff;
        parser->mixer_src_ch = 0xff;
        parser->prev_msg_type = INVALID;

        return 0;
}

// Rough implementaion of queue without overrun check.
static void queue_event(struct snd_motu *motu, u8 msg_type, u8 identifier0, u8 identifier1, u8 val)
{
        struct msg_parser *parser = motu->message_parser;
        unsigned int pos = parser->push_pos;
        u32 entry;

        if (!motu->hwdep || motu->hwdep->used == 0)
                return;

        entry = (msg_type << 24) | (identifier0 << 16) | (identifier1 << 8) | val;
        parser->event_queue[pos] = entry;

        ++pos;
        if (pos >= EVENT_QUEUE_SIZE)
                pos = 0;
        parser->push_pos = pos;
}

void snd_motu_register_dsp_message_parser_parse(const struct amdtp_stream *s,
                                                const struct pkt_desc *desc, unsigned int count)
{
        struct snd_motu *motu = container_of(s, struct snd_motu, tx_stream);
        unsigned int data_block_quadlets = s->data_block_quadlets;
        struct msg_parser *parser = motu->message_parser;
        bool meter_pos_quirk = parser->meter_pos_quirk;
        unsigned int pos = parser->push_pos;
        int i;

        guard(spinlock_irqsave)(&parser->lock);

        for (i = 0; i < count; ++i) {
                __be32 *buffer = desc->ctx_payload;
                unsigned int data_blocks = desc->data_blocks;
                int j;

                desc = amdtp_stream_next_packet_desc(s, desc);

                for (j = 0; j < data_blocks; ++j) {
                        u8 *b = (u8 *)buffer;
                        u8 msg_type = (b[MSG_FLAG_POS] & MSG_FLAG_TYPE_MASK) >> MSG_FLAG_TYPE_SHIFT;
                        u8 val = b[MSG_VALUE_POS];

                        buffer += data_block_quadlets;

                        switch (msg_type) {
                        case MIXER_SELECT:
                        {
                                u8 mixer_ch = val / 0x20;
                                if (mixer_ch < SNDRV_FIREWIRE_MOTU_REGISTER_DSP_MIXER_COUNT) {
                                        parser->mixer_src_ch = 0;
                                        parser->mixer_ch = mixer_ch;
                                }
                                break;
                        }
                        case MIXER_SRC_GAIN:
                        case MIXER_SRC_PAN:
                        case MIXER_SRC_FLAG:
                        case MIXER_SRC_PAIRED_BALANCE:
                        case MIXER_SRC_PAIRED_WIDTH:
                        {
                                struct snd_firewire_motu_register_dsp_parameter *param = &parser->param;
                                u8 mixer_ch = parser->mixer_ch;
                                u8 mixer_src_ch = parser->mixer_src_ch;

                                if (msg_type != parser->prev_mixer_src_type)
                                        mixer_src_ch = 0;
                                else
                                        ++mixer_src_ch;
                                parser->prev_mixer_src_type = msg_type;

                                if (mixer_ch < SNDRV_FIREWIRE_MOTU_REGISTER_DSP_MIXER_COUNT &&
                                    mixer_src_ch < SNDRV_FIREWIRE_MOTU_REGISTER_DSP_MIXER_SRC_COUNT) {
                                        u8 mixer_ch = parser->mixer_ch;

                                        switch (msg_type) {
                                        case MIXER_SRC_GAIN:
                                                if (param->mixer.source[mixer_ch].gain[mixer_src_ch] != val) {
                                                        queue_event(motu, msg_type, mixer_ch, mixer_src_ch, val);
                                                        param->mixer.source[mixer_ch].gain[mixer_src_ch] = val;
                                                }
                                                break;
                                        case MIXER_SRC_PAN:
                                                if (param->mixer.source[mixer_ch].pan[mixer_src_ch] != val) {
                                                        queue_event(motu, msg_type, mixer_ch, mixer_src_ch, val);
                                                        param->mixer.source[mixer_ch].pan[mixer_src_ch] = val;
                                                }
                                                break;
                                        case MIXER_SRC_FLAG:
                                                if (param->mixer.source[mixer_ch].flag[mixer_src_ch] != val) {
                                                        queue_event(motu, msg_type, mixer_ch, mixer_src_ch, val);
                                                        param->mixer.source[mixer_ch].flag[mixer_src_ch] = val;
                                                }
                                                break;
                                        case MIXER_SRC_PAIRED_BALANCE:
                                                if (param->mixer.source[mixer_ch].paired_balance[mixer_src_ch] != val) {
                                                        queue_event(motu, msg_type, mixer_ch, mixer_src_ch, val);
                                                        param->mixer.source[mixer_ch].paired_balance[mixer_src_ch] = val;
                                                }
                                                break;
                                        case MIXER_SRC_PAIRED_WIDTH:
                                                if (param->mixer.source[mixer_ch].paired_width[mixer_src_ch] != val) {
                                                        queue_event(motu, msg_type, mixer_ch, mixer_src_ch, val);
                                                        param->mixer.source[mixer_ch].paired_width[mixer_src_ch] = val;
                                                }
                                                break;
                                        default:
                                                break;
                                        }

                                        parser->mixer_src_ch = mixer_src_ch;
                                }
                                break;
                        }
                        case MIXER_OUTPUT_PAIRED_VOLUME:
                        case MIXER_OUTPUT_PAIRED_FLAG:
                        {
                                struct snd_firewire_motu_register_dsp_parameter *param = &parser->param;
                                u8 mixer_ch = parser->mixer_ch;

                                if (mixer_ch < SNDRV_FIREWIRE_MOTU_REGISTER_DSP_MIXER_COUNT) {
                                        switch (msg_type) {
                                        case MIXER_OUTPUT_PAIRED_VOLUME:
                                                if (param->mixer.output.paired_volume[mixer_ch] != val) {
                                                        queue_event(motu, msg_type, mixer_ch, 0, val);
                                                        param->mixer.output.paired_volume[mixer_ch] = val;
                                                }
                                                break;
                                        case MIXER_OUTPUT_PAIRED_FLAG:
                                                if (param->mixer.output.paired_flag[mixer_ch] != val) {
                                                        queue_event(motu, msg_type, mixer_ch, 0, val);
                                                        param->mixer.output.paired_flag[mixer_ch] = val;
                                                }
                                                break;
                                        default:
                                                break;
                                        }
                                }
                                break;
                        }
                        case MAIN_OUTPUT_PAIRED_VOLUME:
                                if (parser->param.output.main_paired_volume != val) {
                                        queue_event(motu, msg_type, 0, 0, val);
                                        parser->param.output.main_paired_volume = val;
                                }
                                break;
                        case HP_OUTPUT_PAIRED_VOLUME:
                                if (parser->param.output.hp_paired_volume != val) {
                                        queue_event(motu, msg_type, 0, 0, val);
                                        parser->param.output.hp_paired_volume = val;
                                }
                                break;
                        case HP_OUTPUT_PAIRED_ASSIGNMENT:
                                if (parser->param.output.hp_paired_assignment != val) {
                                        queue_event(motu, msg_type, 0, 0, val);
                                        parser->param.output.hp_paired_assignment = val;
                                }
                                break;
                        case LINE_INPUT_BOOST:
                                if (parser->param.line_input.boost_flag != val) {
                                        queue_event(motu, msg_type, 0, 0, val);
                                        parser->param.line_input.boost_flag = val;
                                }
                                break;
                        case LINE_INPUT_NOMINAL_LEVEL:
                                if (parser->param.line_input.nominal_level_flag != val) {
                                        queue_event(motu, msg_type, 0, 0, val);
                                        parser->param.line_input.nominal_level_flag = val;
                                }
                                break;
                        case INPUT_GAIN_AND_INVERT:
                        case INPUT_FLAG:
                        {
                                struct snd_firewire_motu_register_dsp_parameter *param = &parser->param;
                                u8 input_ch = parser->input_ch;

                                if (parser->prev_msg_type != msg_type)
                                        input_ch = 0;
                                else
                                        ++input_ch;

                                if (input_ch < SNDRV_FIREWIRE_MOTU_REGISTER_DSP_INPUT_COUNT) {
                                        switch (msg_type) {
                                        case INPUT_GAIN_AND_INVERT:
                                                if (param->input.gain_and_invert[input_ch] != val) {
                                                        queue_event(motu, msg_type, input_ch, 0, val);
                                                        param->input.gain_and_invert[input_ch] = val;
                                                }
                                                break;
                                        case INPUT_FLAG:
                                                if (param->input.flag[input_ch] != val) {
                                                        queue_event(motu, msg_type, input_ch, 0, val);
                                                        param->input.flag[input_ch] = val;
                                                }
                                                break;
                                        default:
                                                break;
                                        }
                                        parser->input_ch = input_ch;
                                }
                                break;
                        }
                        case UNKNOWN_0:
                        case UNKNOWN_2:
                                break;
                        case METER:
                        {
                                u8 pos;

                                if (!meter_pos_quirk)
                                        pos = b[MSG_METER_IDX_POS];
                                else
                                        pos = b[MSG_METER_IDX_POS_4PRE_AE];

                                if (pos < SNDRV_FIREWIRE_MOTU_REGISTER_DSP_METER_INPUT_COUNT) {
                                        parser->meter.data[pos] = val;
                                } else if (pos >= 0x80) {
                                        pos -= (0x80 - SNDRV_FIREWIRE_MOTU_REGISTER_DSP_METER_INPUT_COUNT);

                                        if (pos < SNDRV_FIREWIRE_MOTU_REGISTER_DSP_METER_COUNT)
                                                parser->meter.data[pos] = val;
                                }

                                // The message for meter is interruptible to the series of other
                                // types of messages. Don't cache it.
                                fallthrough;
                        }
                        case INVALID:
                        default:
                                // Don't cache it.
                                continue;
                        }

                        parser->prev_msg_type = msg_type;
                }
        }

        if (pos != parser->push_pos)
                wake_up(&motu->hwdep_wait);
}

void snd_motu_register_dsp_message_parser_copy_meter(struct snd_motu *motu,
                                                struct snd_firewire_motu_register_dsp_meter *meter)
{
        struct msg_parser *parser = motu->message_parser;

        guard(spinlock_irqsave)(&parser->lock);
        memcpy(meter, &parser->meter, sizeof(*meter));
}

void snd_motu_register_dsp_message_parser_copy_parameter(struct snd_motu *motu,
                                        struct snd_firewire_motu_register_dsp_parameter *param)
{
        struct msg_parser *parser = motu->message_parser;

        guard(spinlock_irqsave)(&parser->lock);
        memcpy(param, &parser->param, sizeof(*param));
}

unsigned int snd_motu_register_dsp_message_parser_count_event(struct snd_motu *motu)
{
        struct msg_parser *parser = motu->message_parser;

        if (parser->pull_pos > parser->push_pos)
                return EVENT_QUEUE_SIZE - parser->pull_pos + parser->push_pos;
        else
                return parser->push_pos - parser->pull_pos;
}

bool snd_motu_register_dsp_message_parser_copy_event(struct snd_motu *motu, u32 *event)
{
        struct msg_parser *parser = motu->message_parser;
        unsigned int pos = parser->pull_pos;

        if (pos == parser->push_pos)
                return false;

        guard(spinlock_irqsave)(&parser->lock);

        *event = parser->event_queue[pos];

        ++pos;
        if (pos >= EVENT_QUEUE_SIZE)
                pos = 0;
        parser->pull_pos = pos;

        return true;
}