root/sound/pci/emu10k1/emumpu401.c
// 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;
}