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mpu401_uart.c

/*
 *  Copyright (c) by Jaroslav Kysela <perex@suse.cz>
 *  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
 *
 *   13-03-2003:
 *      Added support for different kind of hardware I/O. Build in choices
 *      are port and mmio. For other kind of I/O, set mpu->read and
 *      mpu->write to your own I/O functions.
 *
 */

#include <sound/driver.h>
#include <asm/io.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/ioport.h>
#include <linux/interrupt.h>
#include <linux/errno.h>
#include <sound/core.h>
#include <sound/mpu401.h>

MODULE_AUTHOR("Jaroslav Kysela <perex@suse.cz>");
MODULE_DESCRIPTION("Routines for control of MPU-401 in UART mode");
MODULE_LICENSE("GPL");

static void snd_mpu401_uart_input_read(mpu401_t * mpu);
static void snd_mpu401_uart_output_write(mpu401_t * mpu);

/*

 */

#define snd_mpu401_input_avail(mpu) (!(mpu->read(mpu, MPU401C(mpu)) & 0x80))
#define snd_mpu401_output_ready(mpu)      (!(mpu->read(mpu, MPU401C(mpu)) & 0x40))

#define MPU401_RESET          0xff
#define MPU401_ENTER_UART     0x3f
#define MPU401_ACK            0xfe

/* Build in lowlevel io */
static void mpu401_write_port(mpu401_t *mpu, unsigned char data, unsigned long addr)
{
      outb(data, addr);
}

static unsigned char mpu401_read_port(mpu401_t *mpu, unsigned long addr)
{
      return inb(addr);
}

static void mpu401_write_mmio(mpu401_t *mpu, unsigned char data, unsigned long addr)
{
      writeb(data, (void __iomem *)addr);
}

static unsigned char mpu401_read_mmio(mpu401_t *mpu, unsigned long addr)
{
      return readb((void __iomem *)addr);
}
/*  */

static void snd_mpu401_uart_clear_rx(mpu401_t *mpu)
{
      int timeout = 100000;
      for (; timeout > 0 && snd_mpu401_input_avail(mpu); timeout--)
            mpu->read(mpu, MPU401D(mpu));
#ifdef CONFIG_SND_DEBUG
      if (timeout <= 0)
            snd_printk("cmd: clear rx timeout (status = 0x%x)\n", mpu->read(mpu, MPU401C(mpu)));
#endif
}

static void _snd_mpu401_uart_interrupt(mpu401_t *mpu)
{
      spin_lock(&mpu->input_lock);
      if (test_bit(MPU401_MODE_BIT_INPUT, &mpu->mode)) {
            snd_mpu401_uart_input_read(mpu);
      } else {
            snd_mpu401_uart_clear_rx(mpu);
      }
      spin_unlock(&mpu->input_lock);
      /* ok. for better Tx performance try do some output when input is done */
      if (test_bit(MPU401_MODE_BIT_OUTPUT, &mpu->mode) &&
          test_bit(MPU401_MODE_BIT_OUTPUT_TRIGGER, &mpu->mode)) {
            spin_lock(&mpu->output_lock);
            snd_mpu401_uart_output_write(mpu);
            spin_unlock(&mpu->output_lock);
      }
}

/**
 * snd_mpu401_uart_interrupt - generic MPU401-UART interrupt handler
 * @irq: the irq number
 * @dev_id: mpu401 instance
 * @regs: the reigster
 *
 * Processes the interrupt for MPU401-UART i/o.
 */
irqreturn_t snd_mpu401_uart_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
      mpu401_t *mpu = dev_id;
      
      if (mpu == NULL)
            return IRQ_NONE;
      _snd_mpu401_uart_interrupt(mpu);
      return IRQ_HANDLED;
}

/*
 * timer callback
 * reprogram the timer and call the interrupt job
 */
static void snd_mpu401_uart_timer(unsigned long data)
{
      mpu401_t *mpu = (mpu401_t *)data;

      spin_lock(&mpu->timer_lock);
      /*mpu->mode |= MPU401_MODE_TIMER;*/
      mpu->timer.expires = 1 + jiffies;
      add_timer(&mpu->timer);
      spin_unlock(&mpu->timer_lock);
      if (mpu->rmidi)
            _snd_mpu401_uart_interrupt(mpu);
}

/*
 * initialize the timer callback if not programmed yet
 */
static void snd_mpu401_uart_add_timer (mpu401_t *mpu, int input)
{
      unsigned long flags;

      spin_lock_irqsave (&mpu->timer_lock, flags);
      if (mpu->timer_invoked == 0) {
            init_timer(&mpu->timer);
            mpu->timer.data = (unsigned long)mpu;
            mpu->timer.function = snd_mpu401_uart_timer;
            mpu->timer.expires = 1 + jiffies;
            add_timer(&mpu->timer);
      } 
      mpu->timer_invoked |= input ? MPU401_MODE_INPUT_TIMER : MPU401_MODE_OUTPUT_TIMER;
      spin_unlock_irqrestore (&mpu->timer_lock, flags);
}

/*
 * remove the timer callback if still active
 */
static void snd_mpu401_uart_remove_timer (mpu401_t *mpu, int input)
{
      unsigned long flags;

      spin_lock_irqsave (&mpu->timer_lock, flags);
      if (mpu->timer_invoked) {
            mpu->timer_invoked &= input ? ~MPU401_MODE_INPUT_TIMER : ~MPU401_MODE_OUTPUT_TIMER;
            if (! mpu->timer_invoked)
                  del_timer(&mpu->timer);
      }
      spin_unlock_irqrestore (&mpu->timer_lock, flags);
}

/*

 */

static void snd_mpu401_uart_cmd(mpu401_t * mpu, unsigned char cmd, int ack)
{
      unsigned long flags;
      int timeout, ok;

      spin_lock_irqsave(&mpu->input_lock, flags);
      if (mpu->hardware != MPU401_HW_TRID4DWAVE) {
            mpu->write(mpu, 0x00, MPU401D(mpu));
            /*snd_mpu401_uart_clear_rx(mpu);*/
      }
      /* ok. standard MPU-401 initialization */
      if (mpu->hardware != MPU401_HW_SB) {
            for (timeout = 1000; timeout > 0 && !snd_mpu401_output_ready(mpu); timeout--)
                  udelay(10);
#ifdef CONFIG_SND_DEBUG
            if (!timeout)
                  snd_printk("cmd: tx timeout (status = 0x%x)\n", mpu->read(mpu, MPU401C(mpu)));
#endif
      }
      mpu->write(mpu, cmd, MPU401C(mpu));
      if (ack) {
            ok = 0;
            timeout = 10000;
            while (!ok && timeout-- > 0) {
                  if (snd_mpu401_input_avail(mpu)) {
                        if (mpu->read(mpu, MPU401D(mpu)) == MPU401_ACK)
                              ok = 1;
                  }
            }
            if (!ok && mpu->read(mpu, MPU401D(mpu)) == MPU401_ACK)
                  ok = 1;
      } else {
            ok = 1;
      }
      spin_unlock_irqrestore(&mpu->input_lock, flags);
      if (! ok)
            snd_printk("cmd: 0x%x failed at 0x%lx (status = 0x%x, data = 0x%x)\n", cmd, mpu->port, mpu->read(mpu, MPU401C(mpu)), mpu->read(mpu, MPU401D(mpu)));
      // snd_printk("cmd: 0x%x at 0x%lx (status = 0x%x, data = 0x%x)\n", cmd, mpu->port, mpu->read(mpu, MPU401C(mpu)), mpu->read(mpu, MPU401D(mpu)));
}

/*
 * input/output open/close - protected by open_mutex in rawmidi.c
 */
static int snd_mpu401_uart_input_open(snd_rawmidi_substream_t * substream)
{
      mpu401_t *mpu;
      int err;

      mpu = substream->rmidi->private_data;
      if (mpu->open_input && (err = mpu->open_input(mpu)) < 0)
            return err;
      if (! test_bit(MPU401_MODE_BIT_OUTPUT, &mpu->mode)) {
            snd_mpu401_uart_cmd(mpu, MPU401_RESET, 1);
            snd_mpu401_uart_cmd(mpu, MPU401_ENTER_UART, 1);
      }
      mpu->substream_input = substream;
      set_bit(MPU401_MODE_BIT_INPUT, &mpu->mode);
      return 0;
}

static int snd_mpu401_uart_output_open(snd_rawmidi_substream_t * substream)
{
      mpu401_t *mpu;
      int err;

      mpu = substream->rmidi->private_data;
      if (mpu->open_output && (err = mpu->open_output(mpu)) < 0)
            return err;
      if (! test_bit(MPU401_MODE_BIT_INPUT, &mpu->mode)) {
            snd_mpu401_uart_cmd(mpu, MPU401_RESET, 1);
            snd_mpu401_uart_cmd(mpu, MPU401_ENTER_UART, 1);
      }
      mpu->substream_output = substream;
      set_bit(MPU401_MODE_BIT_OUTPUT, &mpu->mode);
      return 0;
}

static int snd_mpu401_uart_input_close(snd_rawmidi_substream_t * substream)
{
      mpu401_t *mpu;

      mpu = substream->rmidi->private_data;
      clear_bit(MPU401_MODE_BIT_INPUT, &mpu->mode);
      mpu->substream_input = NULL;
      if (! test_bit(MPU401_MODE_BIT_OUTPUT, &mpu->mode))
            snd_mpu401_uart_cmd(mpu, MPU401_RESET, 0);
      if (mpu->close_input)
            mpu->close_input(mpu);
      return 0;
}

static int snd_mpu401_uart_output_close(snd_rawmidi_substream_t * substream)
{
      mpu401_t *mpu;

      mpu = substream->rmidi->private_data;
      clear_bit(MPU401_MODE_BIT_OUTPUT, &mpu->mode);
      mpu->substream_output = NULL;
      if (! test_bit(MPU401_MODE_BIT_INPUT, &mpu->mode))
            snd_mpu401_uart_cmd(mpu, MPU401_RESET, 0);
      if (mpu->close_output)
            mpu->close_output(mpu);
      return 0;
}

/*
 * trigger input callback
 */
static void snd_mpu401_uart_input_trigger(snd_rawmidi_substream_t * substream, int up)
{
      unsigned long flags;
      mpu401_t *mpu;
      int max = 64;

      mpu = substream->rmidi->private_data;
      if (up) {
            if (! test_and_set_bit(MPU401_MODE_BIT_INPUT_TRIGGER, &mpu->mode)) {
                  /* first time - flush FIFO */
                  while (max-- > 0)
                        mpu->read(mpu, MPU401D(mpu));
                  if (mpu->irq < 0)
                        snd_mpu401_uart_add_timer(mpu, 1);
            }
            
            /* read data in advance */
            spin_lock_irqsave(&mpu->input_lock, flags);
            snd_mpu401_uart_input_read(mpu);
            spin_unlock_irqrestore(&mpu->input_lock, flags);
      } else {
            if (mpu->irq < 0)
                  snd_mpu401_uart_remove_timer(mpu, 1);
            clear_bit(MPU401_MODE_BIT_INPUT_TRIGGER, &mpu->mode);
      }
}

/*
 * transfer input pending data
 * call with input_lock spinlock held
 */
static void snd_mpu401_uart_input_read(mpu401_t * mpu)
{
      int max = 128;
      unsigned char byte;

      while (max-- > 0) {
            if (snd_mpu401_input_avail(mpu)) {
                  byte = mpu->read(mpu, MPU401D(mpu));
                  if (test_bit(MPU401_MODE_BIT_INPUT_TRIGGER, &mpu->mode))
                        snd_rawmidi_receive(mpu->substream_input, &byte, 1);
            } else {
                  break; /* input not available */
            }
      }
}

/*
 *  Tx FIFO sizes:
 *    CS4237B                 - 16 bytes
 *    AudioDrive ES1688         - 12 bytes
 *    S3 SonicVibes             -  8 bytes
 *    SoundBlaster AWE 64       -  2 bytes (ugly hardware)
 */

/*
 * write output pending bytes
 * call with output_lock spinlock held
 */
static void snd_mpu401_uart_output_write(mpu401_t * mpu)
{
      unsigned char byte;
      int max = 256, timeout;

      do {
            if (snd_rawmidi_transmit_peek(mpu->substream_output, &byte, 1) == 1) {
                  for (timeout = 100; timeout > 0; timeout--) {
                        if (snd_mpu401_output_ready(mpu)) {
                              mpu->write(mpu, byte, MPU401D(mpu));
                              snd_rawmidi_transmit_ack(mpu->substream_output, 1);
                              break;
                        }
                  }
                  if (timeout == 0)
                        break;      /* Tx FIFO full - try again later */
            } else {
                  snd_mpu401_uart_remove_timer (mpu, 0);
                  break;      /* no other data - leave the tx loop */
            }
      } while (--max > 0);
}

/*
 * output trigger callback
 */
static void snd_mpu401_uart_output_trigger(snd_rawmidi_substream_t * substream, int up)
{
      unsigned long flags;
      mpu401_t *mpu;

      mpu = substream->rmidi->private_data;
      if (up) {
            set_bit(MPU401_MODE_BIT_OUTPUT_TRIGGER, &mpu->mode);

            /* try to add the timer at each output trigger,
             * since the output timer might have been removed in
             * snd_mpu401_uart_output_write().
             */
            snd_mpu401_uart_add_timer(mpu, 0);

            /* output pending data */
            spin_lock_irqsave(&mpu->output_lock, flags);
            snd_mpu401_uart_output_write(mpu);
            spin_unlock_irqrestore(&mpu->output_lock, flags);
      } else {
            snd_mpu401_uart_remove_timer(mpu, 0);
            clear_bit(MPU401_MODE_BIT_OUTPUT_TRIGGER, &mpu->mode);
      }
}

/*

 */

static snd_rawmidi_ops_t snd_mpu401_uart_output =
{
      .open =           snd_mpu401_uart_output_open,
      .close =    snd_mpu401_uart_output_close,
      .trigger =  snd_mpu401_uart_output_trigger,
};

static snd_rawmidi_ops_t snd_mpu401_uart_input =
{
      .open =           snd_mpu401_uart_input_open,
      .close =    snd_mpu401_uart_input_close,
      .trigger =  snd_mpu401_uart_input_trigger,
};

static void snd_mpu401_uart_free(snd_rawmidi_t *rmidi)
{
      mpu401_t *mpu = rmidi->private_data;
      if (mpu->irq_flags && mpu->irq >= 0)
            free_irq(mpu->irq, (void *) mpu);
      release_and_free_resource(mpu->res);
      kfree(mpu);
}

/**
 * snd_mpu401_uart_new - create an MPU401-UART instance
 * @card: the card instance
 * @device: the device index, zero-based
 * @hardware: the hardware type, MPU401_HW_XXXX
 * @port: the base address of MPU401 port
 * @integrated: non-zero if the port was already reserved by the chip
 * @irq: the irq number, -1 if no interrupt for mpu
 * @irq_flags: the irq request flags (SA_XXX), 0 if irq was already reserved.
 * @rrawmidi: the pointer to store the new rawmidi instance
 *
 * Creates a new MPU-401 instance.
 *
 * Note that the rawmidi instance is returned on the rrawmidi argument,
 * not the mpu401 instance itself.  To access to the mpu401 instance,
 * cast from rawmidi->private_data (with mpu401_t magic-cast).
 *
 * Returns zero if successful, or a negative error code.
 */
int snd_mpu401_uart_new(snd_card_t * card, int device,
                  unsigned short hardware,
                  unsigned long port, int integrated,
                  int irq, int irq_flags,
                  snd_rawmidi_t ** rrawmidi)
{
      mpu401_t *mpu;
      snd_rawmidi_t *rmidi;
      int err;

      if (rrawmidi)
            *rrawmidi = NULL;
      if ((err = snd_rawmidi_new(card, "MPU-401U", device, 1, 1, &rmidi)) < 0)
            return err;
      mpu = kzalloc(sizeof(*mpu), GFP_KERNEL);
      if (mpu == NULL) {
            snd_device_free(card, rmidi);
            return -ENOMEM;
      }
      rmidi->private_data = mpu;
      rmidi->private_free = snd_mpu401_uart_free;
      spin_lock_init(&mpu->input_lock);
      spin_lock_init(&mpu->output_lock);
      spin_lock_init(&mpu->timer_lock);
      mpu->hardware = hardware;
      if (!integrated) {
            int res_size = hardware == MPU401_HW_PC98II ? 4 : 2;
            if ((mpu->res = request_region(port, res_size, "MPU401 UART")) == NULL) {
                  snd_printk(KERN_ERR "mpu401_uart: unable to grab port 0x%lx size %d\n", port, res_size);
                  snd_device_free(card, rmidi);
                  return -EBUSY;
            }
      }
      switch (hardware) {
      case MPU401_HW_AUREAL:
            mpu->write = mpu401_write_mmio;
            mpu->read = mpu401_read_mmio;
            break;
      default:
            mpu->write = mpu401_write_port;
            mpu->read = mpu401_read_port;
            break;
      }
      mpu->port = port;
      if (hardware == MPU401_HW_PC98II)
            mpu->cport = port + 2;
      else
            mpu->cport = port + 1;
      if (irq >= 0 && irq_flags) {
            if (request_irq(irq, snd_mpu401_uart_interrupt, irq_flags, "MPU401 UART", (void *) mpu)) {
                  snd_printk(KERN_ERR "mpu401_uart: unable to grab IRQ %d\n", irq);
                  snd_device_free(card, rmidi);
                  return -EBUSY;
            }
      }
      mpu->irq = irq;
      mpu->irq_flags = irq_flags;
      if (card->shortname[0])
            snprintf(rmidi->name, sizeof(rmidi->name), "%s MIDI", card->shortname);
      else
            sprintf(rmidi->name, "MPU-401 MIDI %d-%d", card->number, device);
      snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT, &snd_mpu401_uart_output);
      snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT, &snd_mpu401_uart_input);
      rmidi->info_flags |= SNDRV_RAWMIDI_INFO_OUTPUT |
                           SNDRV_RAWMIDI_INFO_INPUT |
                           SNDRV_RAWMIDI_INFO_DUPLEX;
      mpu->rmidi = rmidi;
      if (rrawmidi)
            *rrawmidi = rmidi;
      return 0;
}

EXPORT_SYMBOL(snd_mpu401_uart_interrupt);
EXPORT_SYMBOL(snd_mpu401_uart_new);

/*
 *  INIT part
 */

static int __init alsa_mpu401_uart_init(void)
{
      return 0;
}

static void __exit alsa_mpu401_uart_exit(void)
{
}

module_init(alsa_mpu401_uart_init)
module_exit(alsa_mpu401_uart_exit)

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