msnd_midi.c

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/*
 *  Copyright (c) by Jaroslav Kysela <[email protected]>
 *  Copyright (c) 2009 by Krzysztof Helt
 *  Routines for control of MPU-401 in UART mode
 *
 *  MPU-401 supports UART mode which is not capable generate transmit
 *  interrupts thus output is done via polling. Also, if irq < 0, then
 *  input is done also via polling. Do not expect good performance.
 *
 *
 *   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.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 */

#include <linux/io.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/ioport.h>
#include <linux/errno.h>
#include <linux/export.h>
#include <sound/core.h>
#include <sound/rawmidi.h>

#include "msnd.h"

#define MSNDMIDI_MODE_BIT_INPUT     0
#define MSNDMIDI_MODE_BIT_OUTPUT        1
#define MSNDMIDI_MODE_BIT_INPUT_TRIGGER 2
#define MSNDMIDI_MODE_BIT_OUTPUT_TRIGGER    3

struct snd_msndmidi {
    struct snd_msnd *dev;

    unsigned long mode;     /* MSNDMIDI_MODE_XXXX */

    struct snd_rawmidi_substream *substream_input;

    spinlock_t input_lock;
};

/*
 * input/output open/close - protected by open_mutex in rawmidi.c
 */
static int snd_msndmidi_input_open(struct snd_rawmidi_substream *substream)
{
    struct snd_msndmidi *mpu;

    snd_printdd("snd_msndmidi_input_open()\n");

    mpu = substream->rmidi->private_data;

    mpu->substream_input = substream;

    snd_msnd_enable_irq(mpu->dev);

    snd_msnd_send_dsp_cmd(mpu->dev, HDEX_MIDI_IN_START);
    set_bit(MSNDMIDI_MODE_BIT_INPUT, &mpu->mode);
    return 0;
}

static int snd_msndmidi_input_close(struct snd_rawmidi_substream *substream)
{
    struct snd_msndmidi *mpu;

    mpu = substream->rmidi->private_data;
    snd_msnd_send_dsp_cmd(mpu->dev, HDEX_MIDI_IN_STOP);
    clear_bit(MSNDMIDI_MODE_BIT_INPUT, &mpu->mode);
    mpu->substream_input = NULL;
    snd_msnd_disable_irq(mpu->dev);
    return 0;
}

static void snd_msndmidi_input_drop(struct snd_msndmidi *mpu)
{
    u16 tail;

    tail = readw(mpu->dev->MIDQ + JQS_wTail);
    writew(tail, mpu->dev->MIDQ + JQS_wHead);
}

/*
 * trigger input
 */
static void snd_msndmidi_input_trigger(struct snd_rawmidi_substream *substream,
                    int up)
{
    unsigned long flags;
    struct snd_msndmidi *mpu;

    snd_printdd("snd_msndmidi_input_trigger(, %i)\n", up);

    mpu = substream->rmidi->private_data;
    spin_lock_irqsave(&mpu->input_lock, flags);
    if (up) {
        if (!test_and_set_bit(MSNDMIDI_MODE_BIT_INPUT_TRIGGER,
                      &mpu->mode))
            snd_msndmidi_input_drop(mpu);
    } else {
        clear_bit(MSNDMIDI_MODE_BIT_INPUT_TRIGGER, &mpu->mode);
    }
    spin_unlock_irqrestore(&mpu->input_lock, flags);
    if (up)
        snd_msndmidi_input_read(mpu);
}

void snd_msndmidi_input_read(void *mpuv)
{
    unsigned long flags;
    struct snd_msndmidi *mpu = mpuv;
    void *pwMIDQData = mpu->dev->mappedbase + MIDQ_DATA_BUFF;

    spin_lock_irqsave(&mpu->input_lock, flags);
    while (readw(mpu->dev->MIDQ + JQS_wTail) !=
           readw(mpu->dev->MIDQ + JQS_wHead)) {
        u16 wTmp, val;
        val = readw(pwMIDQData + 2 * readw(mpu->dev->MIDQ + JQS_wHead));

            if (test_bit(MSNDMIDI_MODE_BIT_INPUT_TRIGGER,
                     &mpu->mode))
                snd_rawmidi_receive(mpu->substream_input,
                            (unsigned char *)&val, 1);

        wTmp = readw(mpu->dev->MIDQ + JQS_wHead) + 1;
        if (wTmp > readw(mpu->dev->MIDQ + JQS_wSize))
            writew(0,  mpu->dev->MIDQ + JQS_wHead);
        else
            writew(wTmp,  mpu->dev->MIDQ + JQS_wHead);
    }
    spin_unlock_irqrestore(&mpu->input_lock, flags);
}
EXPORT_SYMBOL(snd_msndmidi_input_read);

static struct snd_rawmidi_ops snd_msndmidi_input = {
    .open =     snd_msndmidi_input_open,
    .close =    snd_msndmidi_input_close,
    .trigger =  snd_msndmidi_input_trigger,
};

static void snd_msndmidi_free(struct snd_rawmidi *rmidi)
{
    struct snd_msndmidi *mpu = rmidi->private_data;
    kfree(mpu);
}

int snd_msndmidi_new(struct snd_card *card, int device)
{
    struct snd_msnd *chip = card->private_data;
    struct snd_msndmidi *mpu;
    struct snd_rawmidi *rmidi;
    int err;

    err = snd_rawmidi_new(card, "MSND-MIDI", device, 1, 1, &rmidi);
    if (err < 0)
        return err;
    mpu = kzalloc(sizeof(*mpu), GFP_KERNEL);
    if (mpu == NULL) {
        snd_device_free(card, rmidi);
        return -ENOMEM;
    }
    mpu->dev = chip;
    chip->msndmidi_mpu = mpu;
    rmidi->private_data = mpu;
    rmidi->private_free = snd_msndmidi_free;
    spin_lock_init(&mpu->input_lock);
    strcpy(rmidi->name, "MSND MIDI");
    snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT,
                &snd_msndmidi_input);
    rmidi->info_flags |= SNDRV_RAWMIDI_INFO_INPUT;
    return 0;
}