mpu401_uart.c

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/*
 *  Copyright (c) by Jaroslav Kysela <[email protected]>
 *  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. Without interrupt,
 *  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 <asm/io.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/ioport.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/errno.h>
#include <sound/core.h>
#include <sound/mpu401.h>

MODULE_AUTHOR("Jaroslav Kysela <[email protected]>");
MODULE_DESCRIPTION("Routines for control of MPU-401 in UART mode");
MODULE_LICENSE("GPL");

static void snd_mpu401_uart_input_read(struct snd_mpu401 * mpu);
static void snd_mpu401_uart_output_write(struct snd_mpu401 * mpu);

/*

 */

#define snd_mpu401_input_avail(mpu) \
    (!(mpu->read(mpu, MPU401C(mpu)) & MPU401_RX_EMPTY))
#define snd_mpu401_output_ready(mpu) \
    (!(mpu->read(mpu, MPU401C(mpu)) & MPU401_TX_FULL))

/* Build in lowlevel io */
static void mpu401_write_port(struct snd_mpu401 *mpu, unsigned char data,
                  unsigned long addr)
{
    outb(data, addr);
}

static unsigned char mpu401_read_port(struct snd_mpu401 *mpu,
                      unsigned long addr)
{
    return inb(addr);
}

static void mpu401_write_mmio(struct snd_mpu401 *mpu, unsigned char data,
                  unsigned long addr)
{
    writeb(data, (void __iomem *)addr);
}

static unsigned char mpu401_read_mmio(struct snd_mpu401 *mpu,
                      unsigned long addr)
{
    return readb((void __iomem *)addr);
}
/*  */

static void snd_mpu401_uart_clear_rx(struct snd_mpu401 *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(KERN_ERR "cmd: clear rx timeout (status = 0x%x)\n",
               mpu->read(mpu, MPU401C(mpu)));
#endif
}

static void uart_interrupt_tx(struct snd_mpu401 *mpu)
{
    unsigned long flags;

    if (test_bit(MPU401_MODE_BIT_OUTPUT, &mpu->mode) &&
        test_bit(MPU401_MODE_BIT_OUTPUT_TRIGGER, &mpu->mode)) {
        spin_lock_irqsave(&mpu->output_lock, flags);
        snd_mpu401_uart_output_write(mpu);
        spin_unlock_irqrestore(&mpu->output_lock, flags);
    }
}

static void _snd_mpu401_uart_interrupt(struct snd_mpu401 *mpu)
{
    unsigned long flags;

    if (mpu->info_flags & MPU401_INFO_INPUT) {
        spin_lock_irqsave(&mpu->input_lock, flags);
        if (test_bit(MPU401_MODE_BIT_INPUT, &mpu->mode))
            snd_mpu401_uart_input_read(mpu);
        else
            snd_mpu401_uart_clear_rx(mpu);
        spin_unlock_irqrestore(&mpu->input_lock, flags);
    }
    if (! (mpu->info_flags & MPU401_INFO_TX_IRQ))
        /* ok. for better Tx performance try do some output
           when input is done */
        uart_interrupt_tx(mpu);
}

irqreturn_t snd_mpu401_uart_interrupt(int irq, void *dev_id)
{
    struct snd_mpu401 *mpu = dev_id;
    
    if (mpu == NULL)
        return IRQ_NONE;
    _snd_mpu401_uart_interrupt(mpu);
    return IRQ_HANDLED;
}

EXPORT_SYMBOL(snd_mpu401_uart_interrupt);

irqreturn_t snd_mpu401_uart_interrupt_tx(int irq, void *dev_id)
{
    struct snd_mpu401 *mpu = dev_id;
    
    if (mpu == NULL)
        return IRQ_NONE;
    uart_interrupt_tx(mpu);
    return IRQ_HANDLED;
}

EXPORT_SYMBOL(snd_mpu401_uart_interrupt_tx);

/*
 * timer callback
 * reprogram the timer and call the interrupt job
 */
static void snd_mpu401_uart_timer(unsigned long data)
{
    struct snd_mpu401 *mpu = (struct snd_mpu401 *)data;
    unsigned long flags;

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

/*
 * initialize the timer callback if not programmed yet
 */
static void snd_mpu401_uart_add_timer (struct snd_mpu401 *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 (struct snd_mpu401 *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);
}

/*
 * send a UART command
 * return zero if successful, non-zero for some errors
 */

static int snd_mpu401_uart_cmd(struct snd_mpu401 * 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(KERN_ERR "cmd: tx timeout (status = 0x%x)\n",
                   mpu->read(mpu, MPU401C(mpu)));
#endif
    }
    mpu->write(mpu, cmd, MPU401C(mpu));
    if (ack && !(mpu->info_flags & MPU401_INFO_NO_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(KERN_ERR "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)));
        return 1;
    }
    return 0;
}

static int snd_mpu401_do_reset(struct snd_mpu401 *mpu)
{
    if (snd_mpu401_uart_cmd(mpu, MPU401_RESET, 1))
        return -EIO;
    if (snd_mpu401_uart_cmd(mpu, MPU401_ENTER_UART, 0))
        return -EIO;
    return 0;
}

/*
 * input/output open/close - protected by open_mutex in rawmidi.c
 */
static int snd_mpu401_uart_input_open(struct snd_rawmidi_substream *substream)
{
    struct snd_mpu401 *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)) {
        if (snd_mpu401_do_reset(mpu) < 0)
            goto error_out;
    }
    mpu->substream_input = substream;
    set_bit(MPU401_MODE_BIT_INPUT, &mpu->mode);
    return 0;

error_out:
    if (mpu->open_input && mpu->close_input)
        mpu->close_input(mpu);
    return -EIO;
}

static int snd_mpu401_uart_output_open(struct snd_rawmidi_substream *substream)
{
    struct snd_mpu401 *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)) {
        if (snd_mpu401_do_reset(mpu) < 0)
            goto error_out;
    }
    mpu->substream_output = substream;
    set_bit(MPU401_MODE_BIT_OUTPUT, &mpu->mode);
    return 0;

error_out:
    if (mpu->open_output && mpu->close_output)
        mpu->close_output(mpu);
    return -EIO;
}

static int snd_mpu401_uart_input_close(struct snd_rawmidi_substream *substream)
{
    struct snd_mpu401 *mpu;
    int err = 0;

    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))
        err = snd_mpu401_uart_cmd(mpu, MPU401_RESET, 0);
    if (mpu->close_input)
        mpu->close_input(mpu);
    if (err)
        return -EIO;
    return 0;
}

static int snd_mpu401_uart_output_close(struct snd_rawmidi_substream *substream)
{
    struct snd_mpu401 *mpu;
    int err = 0;

    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))
        err = snd_mpu401_uart_cmd(mpu, MPU401_RESET, 0);
    if (mpu->close_output)
        mpu->close_output(mpu);
    if (err)
        return -EIO;
    return 0;
}

/*
 * trigger input callback
 */
static void
snd_mpu401_uart_input_trigger(struct snd_rawmidi_substream *substream, int up)
{
    unsigned long flags;
    struct snd_mpu401 *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->info_flags & MPU401_INFO_USE_TIMER)
                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->info_flags & MPU401_INFO_USE_TIMER)
            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(struct snd_mpu401 * mpu)
{
    int max = 128;
    unsigned char byte;

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

/*
 *  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(struct snd_mpu401 * mpu)
{
    unsigned char byte;
    int max = 256;

    do {
        if (snd_rawmidi_transmit_peek(mpu->substream_output,
                          &byte, 1) == 1) {
            /*
             * Try twice because there is hardware that insists on
             * setting the output busy bit after each write.
             */
            if (!snd_mpu401_output_ready(mpu) &&
                !snd_mpu401_output_ready(mpu))
                break;  /* Tx FIFO full - try again later */
            mpu->write(mpu, byte, MPU401D(mpu));
            snd_rawmidi_transmit_ack(mpu->substream_output, 1);
        } 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(struct snd_rawmidi_substream *substream, int up)
{
    unsigned long flags;
    struct snd_mpu401 *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().
         */
        if (! (mpu->info_flags & MPU401_INFO_TX_IRQ))
            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 {
        if (! (mpu->info_flags & MPU401_INFO_TX_IRQ))
            snd_mpu401_uart_remove_timer(mpu, 0);
        clear_bit(MPU401_MODE_BIT_OUTPUT_TRIGGER, &mpu->mode);
    }
}

/*

 */

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

static struct snd_rawmidi_ops 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(struct snd_rawmidi *rmidi)
{
    struct snd_mpu401 *mpu = rmidi->private_data;
    if (mpu->irq >= 0)
        free_irq(mpu->irq, (void *) mpu);
    release_and_free_resource(mpu->res);
    kfree(mpu);
}

int snd_mpu401_uart_new(struct snd_card *card, int device,
            unsigned short hardware,
            unsigned long port,
            unsigned int info_flags,
            int irq,
            struct snd_rawmidi ** rrawmidi)
{
    struct snd_mpu401 *mpu;
    struct snd_rawmidi *rmidi;
    int in_enable, out_enable;
    int err;

    if (rrawmidi)
        *rrawmidi = NULL;
    if (! (info_flags & (MPU401_INFO_INPUT | MPU401_INFO_OUTPUT)))
        info_flags |= MPU401_INFO_INPUT | MPU401_INFO_OUTPUT;
    in_enable = (info_flags & MPU401_INFO_INPUT) ? 1 : 0;
    out_enable = (info_flags & MPU401_INFO_OUTPUT) ? 1 : 0;
    if ((err = snd_rawmidi_new(card, "MPU-401U", device,
                   out_enable, in_enable, &rmidi)) < 0)
        return err;
    mpu = kzalloc(sizeof(*mpu), GFP_KERNEL);
    if (mpu == NULL) {
        snd_printk(KERN_ERR "mpu401_uart: cannot allocate\n");
        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;
    mpu->irq = -1;
    if (! (info_flags & MPU401_INFO_INTEGRATED)) {
        int res_size = hardware == MPU401_HW_PC98II ? 4 : 2;
        mpu->res = request_region(port, res_size, "MPU401 UART");
        if (mpu->res == 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;
        }
    }
    if (info_flags & MPU401_INFO_MMIO) {
        mpu->write = mpu401_write_mmio;
        mpu->read = mpu401_read_mmio;
    } else {
        mpu->write = mpu401_write_port;
        mpu->read = mpu401_read_port;
    }
    mpu->port = port;
    if (hardware == MPU401_HW_PC98II)
        mpu->cport = port + 2;
    else
        mpu->cport = port + 1;
    if (irq >= 0) {
        if (request_irq(irq, snd_mpu401_uart_interrupt, 0,
                "MPU401 UART", (void *) mpu)) {
            snd_printk(KERN_ERR "mpu401_uart: "
                   "unable to grab IRQ %d\n", irq);
            snd_device_free(card, rmidi);
            return -EBUSY;
        }
    }
    if (irq < 0 && !(info_flags & MPU401_INFO_IRQ_HOOK))
        info_flags |= MPU401_INFO_USE_TIMER;
    mpu->info_flags = info_flags;
    mpu->irq = irq;
    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);
    if (out_enable) {
        snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT,
                    &snd_mpu401_uart_output);
        rmidi->info_flags |= SNDRV_RAWMIDI_INFO_OUTPUT;
    }
    if (in_enable) {
        snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT,
                    &snd_mpu401_uart_input);
        rmidi->info_flags |= SNDRV_RAWMIDI_INFO_INPUT;
        if (out_enable)
            rmidi->info_flags |= SNDRV_RAWMIDI_INFO_DUPLEX;
    }
    mpu->rmidi = rmidi;
    if (rrawmidi)
        *rrawmidi = rmidi;
    return 0;
}

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)