// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Linux driver for TerraTec DMX 6Fire USB
 *
 * Rawmidi driver
 *
 * Author:      Torsten Schenk <torsten.schenk@zoho.com>
 * Created:     Jan 01, 2011
 * Copyright:   (C) Torsten Schenk
 */

#include <sound/rawmidi.h>

#include "midi.h"
#include "chip.h"
#include "comm.h"

enum {
        MIDI_BUFSIZE = 64
};

static void usb6fire_midi_out_handler(struct urb *urb)
{
        struct midi_runtime *rt = urb->context;
        int ret;

        guard(spinlock_irqsave)(&rt->out_lock);

        if (rt->out) {
                ret = snd_rawmidi_transmit(rt->out, rt->out_buffer + 4,
                                MIDI_BUFSIZE - 4);
                if (ret > 0) { /* more data available, send next packet */
                        rt->out_buffer[1] = ret + 2;
                        rt->out_buffer[3] = rt->out_serial++;
                        urb->transfer_buffer_length = ret + 4;

                        ret = usb_submit_urb(urb, GFP_ATOMIC);
                        if (ret < 0)
                                dev_err(&urb->dev->dev,
                                        "midi out urb submit failed: %d\n",
                                        ret);
                } else /* no more data to transmit */
                        rt->out = NULL;
        }
}

static void usb6fire_midi_in_received(
                struct midi_runtime *rt, u8 *data, int length)
{
        guard(spinlock_irqsave)(&rt->in_lock);
        if (rt->in)
                snd_rawmidi_receive(rt->in, data, length);
}

static int usb6fire_midi_out_open(struct snd_rawmidi_substream *alsa_sub)
{
        return 0;
}

static int usb6fire_midi_out_close(struct snd_rawmidi_substream *alsa_sub)
{
        return 0;
}

static void usb6fire_midi_out_trigger(
                struct snd_rawmidi_substream *alsa_sub, int up)
{
        struct midi_runtime *rt = alsa_sub->rmidi->private_data;
        struct urb *urb = &rt->out_urb;
        __s8 ret;

        guard(spinlock_irqsave)(&rt->out_lock);
        if (up) { /* start transfer */
                if (rt->out) /* we are already transmitting so just return */
                        return;

                ret = snd_rawmidi_transmit(alsa_sub, rt->out_buffer + 4,
                                MIDI_BUFSIZE - 4);
                if (ret > 0) {
                        rt->out_buffer[1] = ret + 2;
                        rt->out_buffer[3] = rt->out_serial++;
                        urb->transfer_buffer_length = ret + 4;

                        ret = usb_submit_urb(urb, GFP_ATOMIC);
                        if (ret < 0)
                                dev_err(&urb->dev->dev,
                                        "midi out urb submit failed: %d\n",
                                        ret);
                        else
                                rt->out = alsa_sub;
                }
        } else if (rt->out == alsa_sub)
                rt->out = NULL;
}

static void usb6fire_midi_out_drain(struct snd_rawmidi_substream *alsa_sub)
{
        struct midi_runtime *rt = alsa_sub->rmidi->private_data;
        int retry = 0;

        while (rt->out && retry++ < 100)
                msleep(10);
}

static int usb6fire_midi_in_open(struct snd_rawmidi_substream *alsa_sub)
{
        return 0;
}

static int usb6fire_midi_in_close(struct snd_rawmidi_substream *alsa_sub)
{
        return 0;
}

static void usb6fire_midi_in_trigger(
                struct snd_rawmidi_substream *alsa_sub, int up)
{
        struct midi_runtime *rt = alsa_sub->rmidi->private_data;

        guard(spinlock_irqsave)(&rt->in_lock);
        if (up)
                rt->in = alsa_sub;
        else
                rt->in = NULL;
}

static const struct snd_rawmidi_ops out_ops = {
        .open = usb6fire_midi_out_open,
        .close = usb6fire_midi_out_close,
        .trigger = usb6fire_midi_out_trigger,
        .drain = usb6fire_midi_out_drain
};

static const struct snd_rawmidi_ops in_ops = {
        .open = usb6fire_midi_in_open,
        .close = usb6fire_midi_in_close,
        .trigger = usb6fire_midi_in_trigger
};

int usb6fire_midi_init(struct sfire_chip *chip)
{
        int ret;
        struct midi_runtime *rt = kzalloc_obj(struct midi_runtime);
        struct comm_runtime *comm_rt = chip->comm;

        if (!rt)
                return -ENOMEM;

        rt->out_buffer = kzalloc(MIDI_BUFSIZE, GFP_KERNEL);
        if (!rt->out_buffer) {
                kfree(rt);
                return -ENOMEM;
        }

        rt->chip = chip;
        rt->in_received = usb6fire_midi_in_received;
        rt->out_buffer[0] = 0x80; /* 'send midi' command */
        rt->out_buffer[1] = 0x00; /* size of data */
        rt->out_buffer[2] = 0x00; /* always 0 */
        spin_lock_init(&rt->in_lock);
        spin_lock_init(&rt->out_lock);

        comm_rt->init_urb(comm_rt, &rt->out_urb, rt->out_buffer, rt,
                        usb6fire_midi_out_handler);

        ret = snd_rawmidi_new(chip->card, "6FireUSB", 0, 1, 1, &rt->instance);
        if (ret < 0) {
                kfree(rt->out_buffer);
                kfree(rt);
                dev_err(&chip->dev->dev, "unable to create midi.\n");
                return ret;
        }
        rt->instance->private_data = rt;
        strscpy(rt->instance->name, "DMX6FireUSB MIDI");
        rt->instance->info_flags = SNDRV_RAWMIDI_INFO_OUTPUT |
                        SNDRV_RAWMIDI_INFO_INPUT |
                        SNDRV_RAWMIDI_INFO_DUPLEX;
        snd_rawmidi_set_ops(rt->instance, SNDRV_RAWMIDI_STREAM_OUTPUT,
                        &out_ops);
        snd_rawmidi_set_ops(rt->instance, SNDRV_RAWMIDI_STREAM_INPUT,
                        &in_ops);

        chip->midi = rt;
        return 0;
}

void usb6fire_midi_abort(struct sfire_chip *chip)
{
        struct midi_runtime *rt = chip->midi;

        if (rt)
                usb_poison_urb(&rt->out_urb);
}

void usb6fire_midi_destroy(struct sfire_chip *chip)
{
        struct midi_runtime *rt = chip->midi;

        kfree(rt->out_buffer);
        kfree(rt);
        chip->midi = NULL;
}