// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
 *  Routines for control of SoundBlaster cards - MIDI interface
 *
 * --
 *
 * Sun May  9 22:54:38 BST 1999 George David Morrison <gdm@gedamo.demon.co.uk>
 *   Fixed typo in snd_sb8dsp_midi_new_device which prevented midi from 
 *   working.
 *
 * Sun May 11 12:34:56 UTC 2003 Clemens Ladisch <clemens@ladisch.de>
 *   Added full duplex UART mode for DSP version 2.0 and later.
 */

#include <linux/io.h>
#include <linux/string.h>
#include <linux/time.h>
#include <sound/core.h>
#include <sound/sb.h>


irqreturn_t snd_sb8dsp_midi_interrupt(struct snd_sb *chip)
{
        struct snd_rawmidi *rmidi;
        int max = 64;
        char byte;

        if (!chip)
                return IRQ_NONE;
        
        rmidi = chip->rmidi;
        if (!rmidi) {
                inb(SBP(chip, DATA_AVAIL));     /* ack interrupt */
                return IRQ_NONE;
        }

        guard(spinlock)(&chip->midi_input_lock);
        while (max-- > 0) {
                if (inb(SBP(chip, DATA_AVAIL)) & 0x80) {
                        byte = inb(SBP(chip, READ));
                        if (chip->open & SB_OPEN_MIDI_INPUT_TRIGGER) {
                                snd_rawmidi_receive(chip->midi_substream_input, &byte, 1);
                        }
                }
        }
        return IRQ_HANDLED;
}

static int snd_sb8dsp_midi_input_open(struct snd_rawmidi_substream *substream)
{
        struct snd_sb *chip;
        unsigned int valid_open_flags;

        chip = substream->rmidi->private_data;
        valid_open_flags = chip->hardware >= SB_HW_20
                ? SB_OPEN_MIDI_OUTPUT | SB_OPEN_MIDI_OUTPUT_TRIGGER : 0;
        scoped_guard(spinlock_irqsave, &chip->open_lock) {
                if (chip->open & ~valid_open_flags)
                        return -EAGAIN;
                chip->open |= SB_OPEN_MIDI_INPUT;
                chip->midi_substream_input = substream;
                if (chip->open & SB_OPEN_MIDI_OUTPUT)
                        return 0;
        }
        snd_sbdsp_reset(chip);          /* reset DSP */
        if (chip->hardware >= SB_HW_20)
                snd_sbdsp_command(chip, SB_DSP_MIDI_UART_IRQ);
        return 0;
}

static int snd_sb8dsp_midi_output_open(struct snd_rawmidi_substream *substream)
{
        struct snd_sb *chip;
        unsigned int valid_open_flags;

        chip = substream->rmidi->private_data;
        valid_open_flags = chip->hardware >= SB_HW_20
                ? SB_OPEN_MIDI_INPUT | SB_OPEN_MIDI_INPUT_TRIGGER : 0;
        scoped_guard(spinlock_irqsave, &chip->open_lock) {
                if (chip->open & ~valid_open_flags)
                        return -EAGAIN;
                chip->open |= SB_OPEN_MIDI_OUTPUT;
                chip->midi_substream_output = substream;
                if (chip->open & SB_OPEN_MIDI_INPUT)
                        return 0;
        }
        snd_sbdsp_reset(chip);          /* reset DSP */
        if (chip->hardware >= SB_HW_20)
                snd_sbdsp_command(chip, SB_DSP_MIDI_UART_IRQ);
        return 0;
}

static int snd_sb8dsp_midi_input_close(struct snd_rawmidi_substream *substream)
{
        struct snd_sb *chip;

        chip = substream->rmidi->private_data;
        scoped_guard(spinlock_irqsave, &chip->open_lock) {
                chip->open &= ~(SB_OPEN_MIDI_INPUT | SB_OPEN_MIDI_INPUT_TRIGGER);
                chip->midi_substream_input = NULL;
                if (chip->open & SB_OPEN_MIDI_OUTPUT)
                        return 0;
        }
        snd_sbdsp_reset(chip);          /* reset DSP */
        return 0;
}

static int snd_sb8dsp_midi_output_close(struct snd_rawmidi_substream *substream)
{
        struct snd_sb *chip;

        chip = substream->rmidi->private_data;
        timer_delete_sync(&chip->midi_timer);
        scoped_guard(spinlock_irqsave, &chip->open_lock) {
                chip->open &= ~(SB_OPEN_MIDI_OUTPUT | SB_OPEN_MIDI_OUTPUT_TRIGGER);
                chip->midi_substream_output = NULL;
                if (chip->open & SB_OPEN_MIDI_INPUT)
                        return 0;
        }
        snd_sbdsp_reset(chip);          /* reset DSP */
        return 0;
}

static void snd_sb8dsp_midi_input_trigger(struct snd_rawmidi_substream *substream, int up)
{
        struct snd_sb *chip;

        chip = substream->rmidi->private_data;
        guard(spinlock_irqsave)(&chip->open_lock);
        if (up) {
                if (!(chip->open & SB_OPEN_MIDI_INPUT_TRIGGER)) {
                        if (chip->hardware < SB_HW_20)
                                snd_sbdsp_command(chip, SB_DSP_MIDI_INPUT_IRQ);
                        chip->open |= SB_OPEN_MIDI_INPUT_TRIGGER;
                }
        } else {
                if (chip->open & SB_OPEN_MIDI_INPUT_TRIGGER) {
                        if (chip->hardware < SB_HW_20)
                                snd_sbdsp_command(chip, SB_DSP_MIDI_INPUT_IRQ);
                        chip->open &= ~SB_OPEN_MIDI_INPUT_TRIGGER;
                }
        }
}

static void snd_sb8dsp_midi_output_write(struct snd_rawmidi_substream *substream)
{
        struct snd_sb *chip;
        char byte;
        int max = 32;

        /* how big is Tx FIFO? */
        chip = substream->rmidi->private_data;
        while (max-- > 0) {
                guard(spinlock_irqsave)(&chip->open_lock);
                if (snd_rawmidi_transmit_peek(substream, &byte, 1) != 1) {
                        chip->open &= ~SB_OPEN_MIDI_OUTPUT_TRIGGER;
                        timer_delete(&chip->midi_timer);
                        break;
                }
                if (chip->hardware >= SB_HW_20) {
                        int timeout = 8;
                        while ((inb(SBP(chip, STATUS)) & 0x80) != 0 && --timeout > 0)
                                ;
                        if (timeout == 0) {
                                /* Tx FIFO full - try again later */
                                break;
                        }
                        outb(byte, SBP(chip, WRITE));
                } else {
                        snd_sbdsp_command(chip, SB_DSP_MIDI_OUTPUT);
                        snd_sbdsp_command(chip, byte);
                }
                snd_rawmidi_transmit_ack(substream, 1);
        }
}

static void snd_sb8dsp_midi_output_timer(struct timer_list *t)
{
        struct snd_sb *chip = timer_container_of(chip, t, midi_timer);
        struct snd_rawmidi_substream *substream = chip->midi_substream_output;

        scoped_guard(spinlock_irqsave, &chip->open_lock) {
                mod_timer(&chip->midi_timer, 1 + jiffies);
        }
        snd_sb8dsp_midi_output_write(substream);
}

static void snd_sb8dsp_midi_output_trigger(struct snd_rawmidi_substream *substream, int up)
{
        struct snd_sb *chip;

        chip = substream->rmidi->private_data;
        scoped_guard(spinlock_irqsave, &chip->open_lock) {
                if (up) {
                        if (!(chip->open & SB_OPEN_MIDI_OUTPUT_TRIGGER)) {
                                mod_timer(&chip->midi_timer, 1 + jiffies);
                                chip->open |= SB_OPEN_MIDI_OUTPUT_TRIGGER;
                        }
                } else {
                        if (chip->open & SB_OPEN_MIDI_OUTPUT_TRIGGER) {
                                chip->open &= ~SB_OPEN_MIDI_OUTPUT_TRIGGER;
                        }
                }
        }

        if (up)
                snd_sb8dsp_midi_output_write(substream);
}

static const struct snd_rawmidi_ops snd_sb8dsp_midi_output =
{
        .open =         snd_sb8dsp_midi_output_open,
        .close =        snd_sb8dsp_midi_output_close,
        .trigger =      snd_sb8dsp_midi_output_trigger,
};

static const struct snd_rawmidi_ops snd_sb8dsp_midi_input =
{
        .open =         snd_sb8dsp_midi_input_open,
        .close =        snd_sb8dsp_midi_input_close,
        .trigger =      snd_sb8dsp_midi_input_trigger,
};

int snd_sb8dsp_midi(struct snd_sb *chip, int device)
{
        struct snd_rawmidi *rmidi;
        int err;

        err = snd_rawmidi_new(chip->card, "SB8 MIDI", device, 1, 1, &rmidi);
        if (err < 0)
                return err;
        strscpy(rmidi->name, "SB8 MIDI");
        snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT, &snd_sb8dsp_midi_output);
        snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT, &snd_sb8dsp_midi_input);
        rmidi->info_flags |= SNDRV_RAWMIDI_INFO_OUTPUT | SNDRV_RAWMIDI_INFO_INPUT;
        if (chip->hardware >= SB_HW_20)
                rmidi->info_flags |= SNDRV_RAWMIDI_INFO_DUPLEX;
        rmidi->private_data = chip;
        timer_setup(&chip->midi_timer, snd_sb8dsp_midi_output_timer, 0);
        chip->rmidi = rmidi;
        return 0;
}