// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
 *  Routines for control of EMU10K1 MPU-401 in UART mode
 */

#include <linux/time.h>
#include <linux/init.h>
#include <sound/core.h>
#include <sound/emu10k1.h>

#define EMU10K1_MIDI_MODE_INPUT		(1<<0)
#define EMU10K1_MIDI_MODE_OUTPUT	(1<<1)

static inline unsigned char mpu401_read(struct snd_emu10k1 *emu,
					struct snd_emu10k1_midi *mpu, int idx)
{
	if (emu->audigy)
		return (unsigned char)snd_emu10k1_ptr_read(emu, mpu->port + idx, 0);
	else
		return inb(emu->port + mpu->port + idx);
}

static inline void mpu401_write(struct snd_emu10k1 *emu,
				struct snd_emu10k1_midi *mpu, int data, int idx)
{
	if (emu->audigy)
		snd_emu10k1_ptr_write(emu, mpu->port + idx, 0, data);
	else
		outb(data, emu->port + mpu->port + idx);
}

#define mpu401_write_data(emu, mpu, data)	mpu401_write(emu, mpu, data, 0)
#define mpu401_write_cmd(emu, mpu, data)	mpu401_write(emu, mpu, data, 1)
#define mpu401_read_data(emu, mpu)		mpu401_read(emu, mpu, 0)
#define mpu401_read_stat(emu, mpu)		mpu401_read(emu, mpu, 1)

#define mpu401_input_avail(emu,mpu)	(!(mpu401_read_stat(emu,mpu) & 0x80))
#define mpu401_output_ready(emu,mpu)	(!(mpu401_read_stat(emu,mpu) & 0x40))

#define MPU401_RESET		0xff
#define MPU401_ENTER_UART	0x3f
#define MPU401_ACK		0xfe

static void mpu401_clear_rx(struct snd_emu10k1 *emu, struct snd_emu10k1_midi *mpu)
{
	int timeout = 100000;
	for (; timeout > 0 && mpu401_input_avail(emu, mpu); timeout--)
		mpu401_read_data(emu, mpu);
#ifdef CONFIG_SND_DEBUG
	if (timeout <= 0)
		dev_err(emu->card->dev,
			"cmd: clear rx timeout (status = 0x%x)\n",
			mpu401_read_stat(emu, mpu));
#endif
}

/*

 */

static void do_emu10k1_midi_interrupt(struct snd_emu10k1 *emu, struct snd_emu10k1_midi *midi, unsigned int status)
{
	unsigned char byte;

	if (midi->rmidi == NULL) {
		snd_emu10k1_intr_disable(emu, midi->tx_enable | midi->rx_enable);
		return;
	}

	scoped_guard(spinlock, &midi->input_lock) {
		if ((status & midi->ipr_rx) && mpu401_input_avail(emu, midi)) {
			if (!(midi->midi_mode & EMU10K1_MIDI_MODE_INPUT)) {
				mpu401_clear_rx(emu, midi);
			} else {
				byte = mpu401_read_data(emu, midi);
				if (midi->substream_input)
					snd_rawmidi_receive(midi->substream_input, &byte, 1);
			}
		}
	}

	scoped_guard(spinlock, &midi->output_lock) {
		if ((status & midi->ipr_tx) && mpu401_output_ready(emu, midi)) {
			if (midi->substream_output &&
			    snd_rawmidi_transmit(midi->substream_output, &byte, 1) == 1) {
				mpu401_write_data(emu, midi, byte);
			} else {
				snd_emu10k1_intr_disable(emu, midi->tx_enable);
			}
		}
	}
}

static void snd_emu10k1_midi_interrupt(struct snd_emu10k1 *emu, unsigned int status)
{
	do_emu10k1_midi_interrupt(emu, &emu->midi, status);
}

static void snd_emu10k1_midi_interrupt2(struct snd_emu10k1 *emu, unsigned int status)
{
	do_emu10k1_midi_interrupt(emu, &emu->midi2, status);
}

static int snd_emu10k1_midi_cmd(struct snd_emu10k1 * emu, struct snd_emu10k1_midi *midi, unsigned char cmd, int ack)
{
	int timeout, ok;

	scoped_guard(spinlock_irq, &midi->input_lock) {
		mpu401_write_data(emu, midi, 0x00);
		/* mpu401_clear_rx(emu, midi); */

		mpu401_write_cmd(emu, midi, cmd);
		if (ack) {
			ok = 0;
			timeout = 10000;
			while (!ok && timeout-- > 0) {
				if (mpu401_input_avail(emu, midi)) {
					if (mpu401_read_data(emu, midi) == MPU401_ACK)
						ok = 1;
				}
			}
			if (!ok && mpu401_read_data(emu, midi) == MPU401_ACK)
				ok = 1;
		} else {
			ok = 1;
		}
	}
	if (!ok) {
		dev_err(emu->card->dev,
			"midi_cmd: 0x%x failed at 0x%lx (status = 0x%x, data = 0x%x)!!!\n",
			   cmd, emu->port,
			   mpu401_read_stat(emu, midi),
			   mpu401_read_data(emu, midi));
		return 1;
	}
	return 0;
}

static int snd_emu10k1_midi_input_open(struct snd_rawmidi_substream *substream)
{
	struct snd_emu10k1 *emu;
	struct snd_emu10k1_midi *midi = (struct snd_emu10k1_midi *)substream->rmidi->private_data;

	emu = midi->emu;
	if (snd_BUG_ON(!emu))
		return -ENXIO;
	scoped_guard(spinlock_irq, &midi->open_lock) {
		midi->midi_mode |= EMU10K1_MIDI_MODE_INPUT;
		midi->substream_input = substream;
		if (midi->midi_mode & EMU10K1_MIDI_MODE_OUTPUT)
			return 0;
	}
	if (snd_emu10k1_midi_cmd(emu, midi, MPU401_RESET, 1))
		return -EIO;
	if (snd_emu10k1_midi_cmd(emu, midi, MPU401_ENTER_UART, 1))
		return -EIO;
	return 0;
}

static int snd_emu10k1_midi_output_open(struct snd_rawmidi_substream *substream)
{
	struct snd_emu10k1 *emu;
	struct snd_emu10k1_midi *midi = (struct snd_emu10k1_midi *)substream->rmidi->private_data;

	emu = midi->emu;
	if (snd_BUG_ON(!emu))
		return -ENXIO;
	scoped_guard(spinlock_irq, &midi->open_lock) {
		midi->midi_mode |= EMU10K1_MIDI_MODE_OUTPUT;
		midi->substream_output = substream;
		if (midi->midi_mode & EMU10K1_MIDI_MODE_INPUT)
			return 0;
	}
	if (snd_emu10k1_midi_cmd(emu, midi, MPU401_RESET, 1))
		return -EIO;
	if (snd_emu10k1_midi_cmd(emu, midi, MPU401_ENTER_UART, 1))
		return -EIO;
	return 0;
}

static int snd_emu10k1_midi_input_close(struct snd_rawmidi_substream *substream)
{
	struct snd_emu10k1 *emu;
	struct snd_emu10k1_midi *midi = (struct snd_emu10k1_midi *)substream->rmidi->private_data;

	emu = midi->emu;
	if (snd_BUG_ON(!emu))
		return -ENXIO;
	scoped_guard(spinlock_irq, &midi->open_lock) {
		snd_emu10k1_intr_disable(emu, midi->rx_enable);
		midi->midi_mode &= ~EMU10K1_MIDI_MODE_INPUT;
		midi->substream_input = NULL;
		if (midi->midi_mode & EMU10K1_MIDI_MODE_OUTPUT)
			return 0;
	}
	return snd_emu10k1_midi_cmd(emu, midi, MPU401_RESET, 0);
}

static int snd_emu10k1_midi_output_close(struct snd_rawmidi_substream *substream)
{
	struct snd_emu10k1 *emu;
	struct snd_emu10k1_midi *midi = (struct snd_emu10k1_midi *)substream->rmidi->private_data;

	emu = midi->emu;
	if (snd_BUG_ON(!emu))
		return -ENXIO;
	scoped_guard(spinlock_irq, &midi->open_lock) {
		snd_emu10k1_intr_disable(emu, midi->tx_enable);
		midi->midi_mode &= ~EMU10K1_MIDI_MODE_OUTPUT;
		midi->substream_output = NULL;
		if (midi->midi_mode & EMU10K1_MIDI_MODE_INPUT)
			return 0;
	}
	return snd_emu10k1_midi_cmd(emu, midi, MPU401_RESET, 0);
}

static void snd_emu10k1_midi_input_trigger(struct snd_rawmidi_substream *substream, int up)
{
	struct snd_emu10k1 *emu;
	struct snd_emu10k1_midi *midi = (struct snd_emu10k1_midi *)substream->rmidi->private_data;
	emu = midi->emu;
	if (snd_BUG_ON(!emu))
		return;

	if (up)
		snd_emu10k1_intr_enable(emu, midi->rx_enable);
	else
		snd_emu10k1_intr_disable(emu, midi->rx_enable);
}

static void snd_emu10k1_midi_output_trigger(struct snd_rawmidi_substream *substream, int up)
{
	struct snd_emu10k1 *emu;
	struct snd_emu10k1_midi *midi = (struct snd_emu10k1_midi *)substream->rmidi->private_data;

	emu = midi->emu;
	if (snd_BUG_ON(!emu))
		return;

	if (up) {
		int max = 4;
		unsigned char byte;
	
		/* try to send some amount of bytes here before interrupts */
		scoped_guard(spinlock_irq, &midi->output_lock) {
			while (max > 0) {
				if (mpu401_output_ready(emu, midi)) {
					if (!(midi->midi_mode & EMU10K1_MIDI_MODE_OUTPUT) ||
					    snd_rawmidi_transmit(substream, &byte, 1) != 1) {
						/* no more data */
						return;
					}
					mpu401_write_data(emu, midi, byte);
					max--;
				} else {
					break;
				}
			}
		}
		snd_emu10k1_intr_enable(emu, midi->tx_enable);
	} else {
		snd_emu10k1_intr_disable(emu, midi->tx_enable);
	}
}

/*

 */

static const struct snd_rawmidi_ops snd_emu10k1_midi_output =
{
	.open =		snd_emu10k1_midi_output_open,
	.close =	snd_emu10k1_midi_output_close,
	.trigger =	snd_emu10k1_midi_output_trigger,
};

static const struct snd_rawmidi_ops snd_emu10k1_midi_input =
{
	.open =		snd_emu10k1_midi_input_open,
	.close =	snd_emu10k1_midi_input_close,
	.trigger =	snd_emu10k1_midi_input_trigger,
};

static void snd_emu10k1_midi_free(struct snd_rawmidi *rmidi)
{
	struct snd_emu10k1_midi *midi = rmidi->private_data;
	midi->interrupt = NULL;
	midi->rmidi = NULL;
}

static int emu10k1_midi_init(struct snd_emu10k1 *emu, struct snd_emu10k1_midi *midi, int device, char *name)
{
	struct snd_rawmidi *rmidi;
	int err;

	err = snd_rawmidi_new(emu->card, name, device, 1, 1, &rmidi);
	if (err < 0)
		return err;
	midi->emu = emu;
	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, &snd_emu10k1_midi_output);
	snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT, &snd_emu10k1_midi_input);
	rmidi->info_flags |= SNDRV_RAWMIDI_INFO_OUTPUT |
	                     SNDRV_RAWMIDI_INFO_INPUT |
	                     SNDRV_RAWMIDI_INFO_DUPLEX;
	rmidi->private_data = midi;
	rmidi->private_free = snd_emu10k1_midi_free;
	midi->rmidi = rmidi;
	return 0;
}

int snd_emu10k1_midi(struct snd_emu10k1 *emu)
{
	struct snd_emu10k1_midi *midi = &emu->midi;
	int err;

	err = emu10k1_midi_init(emu, midi, 0, "EMU10K1 MPU-401 (UART)");
	if (err < 0)
		return err;

	midi->tx_enable = INTE_MIDITXENABLE;
	midi->rx_enable = INTE_MIDIRXENABLE;
	midi->port = MUDATA;
	midi->ipr_tx = IPR_MIDITRANSBUFEMPTY;
	midi->ipr_rx = IPR_MIDIRECVBUFEMPTY;
	midi->interrupt = snd_emu10k1_midi_interrupt;
	return 0;
}

int snd_emu10k1_audigy_midi(struct snd_emu10k1 *emu)
{
	struct snd_emu10k1_midi *midi;
	int err;

	midi = &emu->midi;
	err = emu10k1_midi_init(emu, midi, 0, "Audigy MPU-401 (UART)");
	if (err < 0)
		return err;

	midi->tx_enable = INTE_MIDITXENABLE;
	midi->rx_enable = INTE_MIDIRXENABLE;
	midi->port = A_MUDATA1;
	midi->ipr_tx = IPR_MIDITRANSBUFEMPTY;
	midi->ipr_rx = IPR_MIDIRECVBUFEMPTY;
	midi->interrupt = snd_emu10k1_midi_interrupt;

	midi = &emu->midi2;
	err = emu10k1_midi_init(emu, midi, 1, "Audigy MPU-401 #2");
	if (err < 0)
		return err;

	midi->tx_enable = INTE_A_MIDITXENABLE2;
	midi->rx_enable = INTE_A_MIDIRXENABLE2;
	midi->port = A_MUDATA2;
	midi->ipr_tx = IPR_A_MIDITRANSBUFEMPTY2;
	midi->ipr_rx = IPR_A_MIDIRECVBUFEMPTY2;
	midi->interrupt = snd_emu10k1_midi_interrupt2;
	return 0;
}
