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msnd_midi.c

/*
 *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
 *  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 <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

00042 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;
}

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