// SPDX-License-Identifier: GPL-2.0-or-later
/* 
 *  Copyright 10/16/2005 Tilman Kranz <tilde@tk-sls.de>
 *  Creative Audio MIDI, for the CA0106 Driver
 *  Version: 0.0.1
 *
 *  Changelog:
 *    Implementation is based on mpu401 and emu10k1x and
 *    tested with ca0106.
 *    mpu401: Copyright (c) by Jaroslav Kysela <perex@perex.cz>
 *    emu10k1x: Copyright (c) by Francisco Moraes <fmoraes@nc.rr.com>
 */

#include <linux/spinlock.h>
#include <sound/core.h>
#include <sound/rawmidi.h>

#include "ca_midi.h"

#define ca_midi_write_data(midi, data)  midi->write(midi, data, 0)
#define ca_midi_write_cmd(midi, data)   midi->write(midi, data, 1)
#define ca_midi_read_data(midi)         midi->read(midi, 0)
#define ca_midi_read_stat(midi)         midi->read(midi, 1)
#define ca_midi_input_avail(midi)       (!(ca_midi_read_stat(midi) & midi->input_avail))
#define ca_midi_output_ready(midi)      (!(ca_midi_read_stat(midi) & midi->output_ready))

static void ca_midi_clear_rx(struct snd_ca_midi *midi)
{
        int timeout = 100000;
        for (; timeout > 0 && ca_midi_input_avail(midi); timeout--)
                ca_midi_read_data(midi);
#ifdef CONFIG_SND_DEBUG
        if (timeout <= 0)
                pr_err("ca_midi_clear_rx: timeout (status = 0x%x)\n",
                           ca_midi_read_stat(midi));
#endif
}

static void ca_midi_interrupt(struct snd_ca_midi *midi, unsigned int status)
{
        unsigned char byte;

        if (midi->rmidi == NULL) {
                midi->interrupt_disable(midi,midi->tx_enable | midi->rx_enable);
                return;
        }

        scoped_guard(spinlock, &midi->input_lock) {
                if ((status & midi->ipr_rx) && ca_midi_input_avail(midi)) {
                        if (!(midi->midi_mode & CA_MIDI_MODE_INPUT)) {
                                ca_midi_clear_rx(midi);
                        } else {
                                byte = ca_midi_read_data(midi);
                                if (midi->substream_input)
                                        snd_rawmidi_receive(midi->substream_input, &byte, 1);
                        }
                }
        }

        scoped_guard(spinlock, &midi->output_lock) {
                if ((status & midi->ipr_tx) && ca_midi_output_ready(midi)) {
                        if (midi->substream_output &&
                            snd_rawmidi_transmit(midi->substream_output, &byte, 1) == 1) {
                                ca_midi_write_data(midi, byte);
                        } else {
                                midi->interrupt_disable(midi, midi->tx_enable);
                        }
                }
        }
}

static void ca_midi_cmd(struct snd_ca_midi *midi, unsigned char cmd, int ack)
{
        int timeout, ok;

        scoped_guard(spinlock_irqsave, &midi->input_lock) {
                ca_midi_write_data(midi, 0x00);
                /* ca_midi_clear_rx(midi); */

                ca_midi_write_cmd(midi, cmd);
                if (ack) {
                        ok = 0;
                        timeout = 10000;
                        while (!ok && timeout-- > 0) {
                                if (ca_midi_input_avail(midi)) {
                                        if (ca_midi_read_data(midi) == midi->ack)
                                                ok = 1;
                                }
                        }
                        if (!ok && ca_midi_read_data(midi) == midi->ack)
                                ok = 1;
                } else {
                        ok = 1;
                }
        }
        if (!ok)
                pr_err("ca_midi_cmd: 0x%x failed at 0x%x (status = 0x%x, data = 0x%x)!!!\n",
                           cmd,
                           midi->get_dev_id_port(midi->dev_id),
                           ca_midi_read_stat(midi),
                           ca_midi_read_data(midi));
}

static int ca_midi_input_open(struct snd_rawmidi_substream *substream)
{
        struct snd_ca_midi *midi = substream->rmidi->private_data;
        
        if (snd_BUG_ON(!midi->dev_id))
                return -ENXIO;
        scoped_guard(spinlock_irqsave, &midi->open_lock) {
                midi->midi_mode |= CA_MIDI_MODE_INPUT;
                midi->substream_input = substream;
                if (midi->midi_mode & CA_MIDI_MODE_OUTPUT)
                        return 0;
        }
        ca_midi_cmd(midi, midi->reset, 1);
        ca_midi_cmd(midi, midi->enter_uart, 1);
        return 0;
}

static int ca_midi_output_open(struct snd_rawmidi_substream *substream)
{
        struct snd_ca_midi *midi = substream->rmidi->private_data;

        if (snd_BUG_ON(!midi->dev_id))
                return -ENXIO;
        scoped_guard(spinlock_irqsave, &midi->open_lock) {
                midi->midi_mode |= CA_MIDI_MODE_OUTPUT;
                midi->substream_output = substream;
                if (midi->midi_mode & CA_MIDI_MODE_INPUT)
                        return 0;
        }
        ca_midi_cmd(midi, midi->reset, 1);
        ca_midi_cmd(midi, midi->enter_uart, 1);
        return 0;
}

static int ca_midi_input_close(struct snd_rawmidi_substream *substream)
{
        struct snd_ca_midi *midi = substream->rmidi->private_data;

        if (snd_BUG_ON(!midi->dev_id))
                return -ENXIO;
        scoped_guard(spinlock_irqsave, &midi->open_lock) {
                midi->interrupt_disable(midi, midi->rx_enable);
                midi->midi_mode &= ~CA_MIDI_MODE_INPUT;
                midi->substream_input = NULL;
                if (midi->midi_mode & CA_MIDI_MODE_OUTPUT)
                        return 0;
        }
        ca_midi_cmd(midi, midi->reset, 0);
        return 0;
}

static int ca_midi_output_close(struct snd_rawmidi_substream *substream)
{
        struct snd_ca_midi *midi = substream->rmidi->private_data;

        if (snd_BUG_ON(!midi->dev_id))
                return -ENXIO;
        
        scoped_guard(spinlock_irqsave, &midi->open_lock) {
                midi->interrupt_disable(midi, midi->tx_enable);
                midi->midi_mode &= ~CA_MIDI_MODE_OUTPUT;
                midi->substream_output = NULL;
                if (midi->midi_mode & CA_MIDI_MODE_INPUT)
                        return 0;
        }
        ca_midi_cmd(midi, midi->reset, 0);
        return 0;
}

static void ca_midi_input_trigger(struct snd_rawmidi_substream *substream, int up)
{
        struct snd_ca_midi *midi = substream->rmidi->private_data;

        if (snd_BUG_ON(!midi->dev_id))
                return;

        if (up) {
                midi->interrupt_enable(midi,midi->rx_enable);
        } else {
                midi->interrupt_disable(midi, midi->rx_enable);
        }
}

static void ca_midi_output_trigger(struct snd_rawmidi_substream *substream, int up)
{
        struct snd_ca_midi *midi = substream->rmidi->private_data;

        if (snd_BUG_ON(!midi->dev_id))
                return;

        if (up) {
                int max = 4;
                unsigned char byte;

                scoped_guard(spinlock_irqsave, &midi->output_lock) {
        
                        /* try to send some amount of bytes here before interrupts */
                        while (max > 0) {
                                if (ca_midi_output_ready(midi)) {
                                        if (!(midi->midi_mode & CA_MIDI_MODE_OUTPUT) ||
                                            snd_rawmidi_transmit(substream, &byte, 1) != 1) {
                                                /* no more data */
                                                return;
                                        }
                                        ca_midi_write_data(midi, byte);
                                        max--;
                                } else {
                                        break;
                                }
                        }
                }
                midi->interrupt_enable(midi,midi->tx_enable);

        } else {
                midi->interrupt_disable(midi,midi->tx_enable);
        }
}

static const struct snd_rawmidi_ops ca_midi_output =
{
        .open =         ca_midi_output_open,
        .close =        ca_midi_output_close,
        .trigger =      ca_midi_output_trigger,
};

static const struct snd_rawmidi_ops ca_midi_input =
{
        .open =         ca_midi_input_open,
        .close =        ca_midi_input_close,
        .trigger =      ca_midi_input_trigger,
};

static void ca_midi_free(struct snd_ca_midi *midi)
{
        midi->interrupt = NULL;
        midi->interrupt_enable = NULL;
        midi->interrupt_disable = NULL;
        midi->read = NULL;
        midi->write = NULL;
        midi->get_dev_id_card = NULL;
        midi->get_dev_id_port = NULL;
        midi->rmidi = NULL;
}

static void ca_rmidi_free(struct snd_rawmidi *rmidi)
{
        ca_midi_free(rmidi->private_data);
}

int ca_midi_init(void *dev_id, struct snd_ca_midi *midi, int device, char *name)
{
        struct snd_rawmidi *rmidi;
        int err;

        err = snd_rawmidi_new(midi->get_dev_id_card(midi->dev_id), name, device, 1, 1, &rmidi);
        if (err < 0)
                return err;

        midi->dev_id = dev_id;
        midi->interrupt = ca_midi_interrupt;

        spin_lock_init(&midi->open_lock);
        spin_lock_init(&midi->input_lock);
        spin_lock_init(&midi->output_lock);

        strscpy(rmidi->name, name);
        snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT, &ca_midi_output);
        snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT, &ca_midi_input);
        rmidi->info_flags |= SNDRV_RAWMIDI_INFO_OUTPUT |
                             SNDRV_RAWMIDI_INFO_INPUT |
                             SNDRV_RAWMIDI_INFO_DUPLEX;
        rmidi->private_data = midi;
        rmidi->private_free = ca_rmidi_free;
        
        midi->rmidi = rmidi;
        return 0;
}