midi.c

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/*
 * Linux driver for TerraTec DMX 6Fire USB
 *
 * Rawmidi driver
 *
 * Author:  Torsten Schenk <[email protected]>
 * Created: Jan 01, 2011
 * Copyright:   (C) Torsten Schenk
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

#include <sound/rawmidi.h>

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

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

    spin_lock_irqsave(&rt->out_lock, flags);

    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)
                snd_printk(KERN_ERR PREFIX "midi out urb "
                        "submit failed: %d\n", ret);
        } else /* no more data to transmit */
            rt->out = NULL;
    }
    spin_unlock_irqrestore(&rt->out_lock, flags);
}

static void usb6fire_midi_in_received(
        struct midi_runtime *rt, u8 *data, int length)
{
    unsigned long flags;

    spin_lock_irqsave(&rt->in_lock, flags);
    if (rt->in)
        snd_rawmidi_receive(rt->in, data, length);
    spin_unlock_irqrestore(&rt->in_lock, flags);
}

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;
    unsigned long flags;

    spin_lock_irqsave(&rt->out_lock, flags);
    if (up) { /* start transfer */
        if (rt->out) { /* we are already transmitting so just return */
            spin_unlock_irqrestore(&rt->out_lock, flags);
            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)
                snd_printk(KERN_ERR PREFIX "midi out urb "
                        "submit failed: %d\n", ret);
            else
                rt->out = alsa_sub;
        }
    } else if (rt->out == alsa_sub)
        rt->out = NULL;
    spin_unlock_irqrestore(&rt->out_lock, flags);
}

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;
    unsigned long flags;

    spin_lock_irqsave(&rt->in_lock, flags);
    if (up)
        rt->in = alsa_sub;
    else
        rt->in = NULL;
    spin_unlock_irqrestore(&rt->in_lock, flags);
}

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

int __devinit usb6fire_midi_init(struct sfire_chip *chip)
{
    int ret;
    struct midi_runtime *rt = kzalloc(sizeof(struct midi_runtime),
            GFP_KERNEL);
    struct comm_runtime *comm_rt = chip->comm;

    if (!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);
        snd_printk(KERN_ERR PREFIX "unable to create midi.\n");
        return ret;
    }
    rt->instance->private_data = rt;
    strcpy(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)
{
    kfree(chip->midi);
    chip->midi = NULL;
}