dmabuf.c

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/*
 * sound/oss/dmabuf.c
 *
 * The DMA buffer manager for digitized voice applications
 */
/*
 * Copyright (C) by Hannu Savolainen 1993-1997
 *
 * OSS/Free for Linux is distributed under the GNU GENERAL PUBLIC LICENSE (GPL)
 * Version 2 (June 1991). See the "COPYING" file distributed with this software
 * for more info.
 *
 * Thomas Sailer   : moved several static variables into struct audio_operations
 *                   (which is grossly misnamed btw.) because they have the same
 *                   lifetime as the rest in there and dynamic allocation saves
 *                   12k or so
 * Thomas Sailer   : remove {in,out}_sleep_flag. It was used for the sleeper to
 *                   determine if it was woken up by the expiring timeout or by
 *                   an explicit wake_up. The return value from schedule_timeout
 *           can be used instead; if 0, the wakeup was due to the timeout.
 *
 * Rob Riggs        Added persistent DMA buffers (1998/10/17)
 */

#define BE_CONSERVATIVE
#define SAMPLE_ROUNDUP 0

#include <linux/mm.h>
#include <linux/gfp.h>
#include "sound_config.h"

#define DMAP_FREE_ON_CLOSE      0
#define DMAP_KEEP_ON_CLOSE      1
extern int sound_dmap_flag;

static void dma_reset_output(int dev);
static void dma_reset_input(int dev);
static int local_start_dma(struct audio_operations *adev, unsigned long physaddr, int count, int dma_mode);



static int debugmem;        /* switched off by default */
static int dma_buffsize = DSP_BUFFSIZE;

static long dmabuf_timeout(struct dma_buffparms *dmap)
{
    long tmout;

    tmout = (dmap->fragment_size * HZ) / dmap->data_rate;
    tmout += HZ / 5;    /* Some safety distance */
    if (tmout < (HZ / 2))
        tmout = HZ / 2;
    if (tmout > 20 * HZ)
        tmout = 20 * HZ;
    return tmout;
}

static int sound_alloc_dmap(struct dma_buffparms *dmap)
{
    char *start_addr, *end_addr;
    int dma_pagesize;
    int sz, size;
    struct page *page;

    dmap->mapping_flags &= ~DMA_MAP_MAPPED;

    if (dmap->raw_buf != NULL)
        return 0;   /* Already done */
    if (dma_buffsize < 4096)
        dma_buffsize = 4096;
    dma_pagesize = (dmap->dma < 4) ? (64 * 1024) : (128 * 1024);
    
    /*
     *  Now check for the Cyrix problem.
     */
     
    if(isa_dma_bridge_buggy==2)
        dma_pagesize=32768;
     
    dmap->raw_buf = NULL;
    dmap->buffsize = dma_buffsize;
    if (dmap->buffsize > dma_pagesize)
        dmap->buffsize = dma_pagesize;
    start_addr = NULL;
    /*
     * Now loop until we get a free buffer. Try to get smaller buffer if
     * it fails. Don't accept smaller than 8k buffer for performance
     * reasons.
     */
    while (start_addr == NULL && dmap->buffsize > PAGE_SIZE) {
        for (sz = 0, size = PAGE_SIZE; size < dmap->buffsize; sz++, size <<= 1);
        dmap->buffsize = PAGE_SIZE * (1 << sz);
        start_addr = (char *) __get_free_pages(GFP_ATOMIC|GFP_DMA|__GFP_NOWARN, sz);
        if (start_addr == NULL)
            dmap->buffsize /= 2;
    }

    if (start_addr == NULL) {
        printk(KERN_WARNING "Sound error: Couldn't allocate DMA buffer\n");
        return -ENOMEM;
    } else {
        /* make some checks */
        end_addr = start_addr + dmap->buffsize - 1;

        if (debugmem)
            printk(KERN_DEBUG "sound: start 0x%lx, end 0x%lx\n", (long) start_addr, (long) end_addr);
        
        /* now check if it fits into the same dma-pagesize */

        if (((long) start_addr & ~(dma_pagesize - 1)) != ((long) end_addr & ~(dma_pagesize - 1))
            || end_addr >= (char *) (MAX_DMA_ADDRESS)) {
            printk(KERN_ERR "sound: Got invalid address 0x%lx for %db DMA-buffer\n", (long) start_addr, dmap->buffsize);
            return -EFAULT;
        }
    }
    dmap->raw_buf = start_addr;
    dmap->raw_buf_phys = virt_to_bus(start_addr);

    for (page = virt_to_page(start_addr); page <= virt_to_page(end_addr); page++)
        SetPageReserved(page);
    return 0;
}

static void sound_free_dmap(struct dma_buffparms *dmap)
{
    int sz, size;
    struct page *page;
    unsigned long start_addr, end_addr;

    if (dmap->raw_buf == NULL)
        return;
    if (dmap->mapping_flags & DMA_MAP_MAPPED)
        return;     /* Don't free mmapped buffer. Will use it next time */
    for (sz = 0, size = PAGE_SIZE; size < dmap->buffsize; sz++, size <<= 1);

    start_addr = (unsigned long) dmap->raw_buf;
    end_addr = start_addr + dmap->buffsize;

    for (page = virt_to_page(start_addr); page <= virt_to_page(end_addr); page++)
        ClearPageReserved(page);

    free_pages((unsigned long) dmap->raw_buf, sz);
    dmap->raw_buf = NULL;
}


/* Intel version !!!!!!!!! */

static int sound_start_dma(struct dma_buffparms *dmap, unsigned long physaddr, int count, int dma_mode)
{
    unsigned long flags;
    int chan = dmap->dma;

    /* printk( "Start DMA%d %d, %d\n",  chan,  (int)(physaddr-dmap->raw_buf_phys),  count); */

    flags = claim_dma_lock();
    disable_dma(chan);
    clear_dma_ff(chan);
    set_dma_mode(chan, dma_mode);
    set_dma_addr(chan, physaddr);
    set_dma_count(chan, count);
    enable_dma(chan);
    release_dma_lock(flags);

    return 0;
}

static void dma_init_buffers(struct dma_buffparms *dmap)
{
    dmap->qlen = dmap->qhead = dmap->qtail = dmap->user_counter = 0;
    dmap->byte_counter = 0;
    dmap->max_byte_counter = 8000 * 60 * 60;
    dmap->bytes_in_use = dmap->buffsize;

    dmap->dma_mode = DMODE_NONE;
    dmap->mapping_flags = 0;
    dmap->neutral_byte = 0x80;
    dmap->data_rate = 8000;
    dmap->cfrag = -1;
    dmap->closing = 0;
    dmap->nbufs = 1;
    dmap->flags = DMA_BUSY; /* Other flags off */
}

static int open_dmap(struct audio_operations *adev, int mode, struct dma_buffparms *dmap)
{
    int err;
    
    if (dmap->flags & DMA_BUSY)
        return -EBUSY;
    if ((err = sound_alloc_dmap(dmap)) < 0)
        return err;

    if (dmap->raw_buf == NULL) {
        printk(KERN_WARNING "Sound: DMA buffers not available\n");
        return -ENOSPC; /* Memory allocation failed during boot */
    }
    if (dmap->dma >= 0 && sound_open_dma(dmap->dma, adev->name)) {
        printk(KERN_WARNING "Unable to grab(2) DMA%d for the audio driver\n", dmap->dma);
        return -EBUSY;
    }
    dma_init_buffers(dmap);
    spin_lock_init(&dmap->lock);
    dmap->open_mode = mode;
    dmap->subdivision = dmap->underrun_count = 0;
    dmap->fragment_size = 0;
    dmap->max_fragments = 65536;    /* Just a large value */
    dmap->byte_counter = 0;
    dmap->max_byte_counter = 8000 * 60 * 60;
    dmap->applic_profile = APF_NORMAL;
    dmap->needs_reorg = 1;
    dmap->audio_callback = NULL;
    dmap->callback_parm = 0;
    return 0;
}

static void close_dmap(struct audio_operations *adev, struct dma_buffparms *dmap)
{
    unsigned long flags;
    
    if (dmap->dma >= 0) {
        sound_close_dma(dmap->dma);
        flags=claim_dma_lock();
        disable_dma(dmap->dma);
        release_dma_lock(flags);
    }
    if (dmap->flags & DMA_BUSY)
        dmap->dma_mode = DMODE_NONE;
    dmap->flags &= ~DMA_BUSY;
    
    if (sound_dmap_flag == DMAP_FREE_ON_CLOSE)
        sound_free_dmap(dmap);
}


static unsigned int default_set_bits(int dev, unsigned int bits)
{
    mm_segment_t fs = get_fs();

    set_fs(get_ds());
    audio_devs[dev]->d->ioctl(dev, SNDCTL_DSP_SETFMT, (void __user *)&bits);
    set_fs(fs);
    return bits;
}

static int default_set_speed(int dev, int speed)
{
    mm_segment_t fs = get_fs();

    set_fs(get_ds());
    audio_devs[dev]->d->ioctl(dev, SNDCTL_DSP_SPEED, (void __user *)&speed);
    set_fs(fs);
    return speed;
}

static short default_set_channels(int dev, short channels)
{
    int c = channels;
    mm_segment_t fs = get_fs();

    set_fs(get_ds());
    audio_devs[dev]->d->ioctl(dev, SNDCTL_DSP_CHANNELS, (void __user *)&c);
    set_fs(fs);
    return c;
}

static void check_driver(struct audio_driver *d)
{
    if (d->set_speed == NULL)
        d->set_speed = default_set_speed;
    if (d->set_bits == NULL)
        d->set_bits = default_set_bits;
    if (d->set_channels == NULL)
        d->set_channels = default_set_channels;
}

int DMAbuf_open(int dev, int mode)
{
    struct audio_operations *adev = audio_devs[dev];
    int retval;
    struct dma_buffparms *dmap_in = NULL;
    struct dma_buffparms *dmap_out = NULL;

    if (!adev)
          return -ENXIO;
    if (!(adev->flags & DMA_DUPLEX))
        adev->dmap_in = adev->dmap_out;
    check_driver(adev->d);

    if ((retval = adev->d->open(dev, mode)) < 0)
        return retval;
    dmap_out = adev->dmap_out;
    dmap_in = adev->dmap_in;
    if (dmap_in == dmap_out)
        adev->flags &= ~DMA_DUPLEX;

    if (mode & OPEN_WRITE) {
        if ((retval = open_dmap(adev, mode, dmap_out)) < 0) {
            adev->d->close(dev);
            return retval;
        }
    }
    adev->enable_bits = mode;

    if (mode == OPEN_READ || (mode != OPEN_WRITE && (adev->flags & DMA_DUPLEX))) {
        if ((retval = open_dmap(adev, mode, dmap_in)) < 0) {
            adev->d->close(dev);
            if (mode & OPEN_WRITE)
                close_dmap(adev, dmap_out);
            return retval;
        }
    }
    adev->open_mode = mode;
    adev->go = 1;

    adev->d->set_bits(dev, 8);
    adev->d->set_channels(dev, 1);
    adev->d->set_speed(dev, DSP_DEFAULT_SPEED);
    if (adev->dmap_out->dma_mode == DMODE_OUTPUT) 
        memset(adev->dmap_out->raw_buf, adev->dmap_out->neutral_byte,
               adev->dmap_out->bytes_in_use);
    return 0;
}
/* MUST not hold the spinlock */
void DMAbuf_reset(int dev)
{
    if (audio_devs[dev]->open_mode & OPEN_WRITE)
        dma_reset_output(dev);

    if (audio_devs[dev]->open_mode & OPEN_READ)
        dma_reset_input(dev);
}

static void dma_reset_output(int dev)
{
    struct audio_operations *adev = audio_devs[dev];
    unsigned long flags,f ;
    struct dma_buffparms *dmap = adev->dmap_out;

    if (!(dmap->flags & DMA_STARTED))   /* DMA is not active */
        return;

    /*
     *  First wait until the current fragment has been played completely
     */
    spin_lock_irqsave(&dmap->lock,flags);
    adev->dmap_out->flags |= DMA_SYNCING;

    adev->dmap_out->underrun_count = 0;
    if (!signal_pending(current) && adev->dmap_out->qlen && 
        adev->dmap_out->underrun_count == 0){
        spin_unlock_irqrestore(&dmap->lock,flags);
        interruptible_sleep_on_timeout(&adev->out_sleeper,
                           dmabuf_timeout(dmap));
        spin_lock_irqsave(&dmap->lock,flags);
    }
    adev->dmap_out->flags &= ~(DMA_SYNCING | DMA_ACTIVE);

    /*
     *  Finally shut the device off
     */
    if (!(adev->flags & DMA_DUPLEX) || !adev->d->halt_output)
        adev->d->halt_io(dev);
    else
        adev->d->halt_output(dev);
    adev->dmap_out->flags &= ~DMA_STARTED;
    
    f=claim_dma_lock();
    clear_dma_ff(dmap->dma);
    disable_dma(dmap->dma);
    release_dma_lock(f);
    
    dmap->byte_counter = 0;
    reorganize_buffers(dev, adev->dmap_out, 0);
    dmap->qlen = dmap->qhead = dmap->qtail = dmap->user_counter = 0;
    spin_unlock_irqrestore(&dmap->lock,flags);
}

static void dma_reset_input(int dev)
{
        struct audio_operations *adev = audio_devs[dev];
    unsigned long flags;
    struct dma_buffparms *dmap = adev->dmap_in;

    spin_lock_irqsave(&dmap->lock,flags);
    if (!(adev->flags & DMA_DUPLEX) || !adev->d->halt_input)
        adev->d->halt_io(dev);
    else
        adev->d->halt_input(dev);
    adev->dmap_in->flags &= ~DMA_STARTED;

    dmap->qlen = dmap->qhead = dmap->qtail = dmap->user_counter = 0;
    dmap->byte_counter = 0;
    reorganize_buffers(dev, adev->dmap_in, 1);
    spin_unlock_irqrestore(&dmap->lock,flags);
}
/* MUST be called with holding the dmap->lock */
void DMAbuf_launch_output(int dev, struct dma_buffparms *dmap)
{
    struct audio_operations *adev = audio_devs[dev];

    if (!((adev->enable_bits * adev->go) & PCM_ENABLE_OUTPUT))
        return;     /* Don't start DMA yet */
    dmap->dma_mode = DMODE_OUTPUT;

    if (!(dmap->flags & DMA_ACTIVE) || !(adev->flags & DMA_AUTOMODE) || (dmap->flags & DMA_NODMA)) {
        if (!(dmap->flags & DMA_STARTED)) {
            reorganize_buffers(dev, dmap, 0);
            if (adev->d->prepare_for_output(dev, dmap->fragment_size, dmap->nbufs))
                return;
            if (!(dmap->flags & DMA_NODMA))
                local_start_dma(adev, dmap->raw_buf_phys, dmap->bytes_in_use,DMA_MODE_WRITE);
            dmap->flags |= DMA_STARTED;
        }
        if (dmap->counts[dmap->qhead] == 0)
            dmap->counts[dmap->qhead] = dmap->fragment_size;
        dmap->dma_mode = DMODE_OUTPUT;
        adev->d->output_block(dev, dmap->raw_buf_phys + dmap->qhead * dmap->fragment_size,
                      dmap->counts[dmap->qhead], 1);
        if (adev->d->trigger)
            adev->d->trigger(dev,adev->enable_bits * adev->go);
    }
    dmap->flags |= DMA_ACTIVE;
}

int DMAbuf_sync(int dev)
{
    struct audio_operations *adev = audio_devs[dev];
    unsigned long flags;
    int n = 0;
    struct dma_buffparms *dmap;

    if (!adev->go && !(adev->enable_bits & PCM_ENABLE_OUTPUT))
        return 0;

    if (adev->dmap_out->dma_mode == DMODE_OUTPUT) {
        dmap = adev->dmap_out;
        spin_lock_irqsave(&dmap->lock,flags);
        if (dmap->qlen > 0 && !(dmap->flags & DMA_ACTIVE))
            DMAbuf_launch_output(dev, dmap);
        adev->dmap_out->flags |= DMA_SYNCING;
        adev->dmap_out->underrun_count = 0;
        while (!signal_pending(current) && n++ < adev->dmap_out->nbufs &&
               adev->dmap_out->qlen && adev->dmap_out->underrun_count == 0) {
            long t = dmabuf_timeout(dmap);
            spin_unlock_irqrestore(&dmap->lock,flags);
            /* FIXME: not safe may miss events */
            t = interruptible_sleep_on_timeout(&adev->out_sleeper, t);
            spin_lock_irqsave(&dmap->lock,flags);
            if (!t) {
                adev->dmap_out->flags &= ~DMA_SYNCING;
                spin_unlock_irqrestore(&dmap->lock,flags);
                return adev->dmap_out->qlen;
            }
        }
        adev->dmap_out->flags &= ~(DMA_SYNCING | DMA_ACTIVE);
        
        /*
         * Some devices such as GUS have huge amount of on board RAM for the
         * audio data. We have to wait until the device has finished playing.
         */

        /* still holding the lock */
        if (adev->d->local_qlen) {   /* Device has hidden buffers */
            while (!signal_pending(current) &&
                   adev->d->local_qlen(dev)){
                spin_unlock_irqrestore(&dmap->lock,flags);
                interruptible_sleep_on_timeout(&adev->out_sleeper,
                                   dmabuf_timeout(dmap));
                spin_lock_irqsave(&dmap->lock,flags);
            }
        }
        spin_unlock_irqrestore(&dmap->lock,flags);
    }
    adev->dmap_out->dma_mode = DMODE_NONE;
    return adev->dmap_out->qlen;
}

int DMAbuf_release(int dev, int mode)
{
    struct audio_operations *adev = audio_devs[dev];
    struct dma_buffparms *dmap;
    unsigned long flags;

    dmap = adev->dmap_out;
    if (adev->open_mode & OPEN_WRITE)
        adev->dmap_out->closing = 1;

    if (adev->open_mode & OPEN_READ){
        adev->dmap_in->closing = 1;
        dmap = adev->dmap_in;
    }
    if (adev->open_mode & OPEN_WRITE)
        if (!(adev->dmap_out->mapping_flags & DMA_MAP_MAPPED))
            if (!signal_pending(current) && (adev->dmap_out->dma_mode == DMODE_OUTPUT))
                DMAbuf_sync(dev);
    if (adev->dmap_out->dma_mode == DMODE_OUTPUT)
        memset(adev->dmap_out->raw_buf, adev->dmap_out->neutral_byte, adev->dmap_out->bytes_in_use);

    DMAbuf_reset(dev);
    spin_lock_irqsave(&dmap->lock,flags);
    adev->d->close(dev);

    if (adev->open_mode & OPEN_WRITE)
        close_dmap(adev, adev->dmap_out);

    if (adev->open_mode == OPEN_READ ||
        (adev->open_mode != OPEN_WRITE &&
         (adev->flags & DMA_DUPLEX)))
        close_dmap(adev, adev->dmap_in);
    adev->open_mode = 0;
    spin_unlock_irqrestore(&dmap->lock,flags);
    return 0;
}
/* called with dmap->lock dold */
int DMAbuf_activate_recording(int dev, struct dma_buffparms *dmap)
{
    struct audio_operations *adev = audio_devs[dev];
    int  err;

    if (!(adev->open_mode & OPEN_READ))
        return 0;
    if (!(adev->enable_bits & PCM_ENABLE_INPUT))
        return 0;
    if (dmap->dma_mode == DMODE_OUTPUT) {   /* Direction change */
        /* release lock - it's not recursive */
        spin_unlock_irq(&dmap->lock);
        DMAbuf_sync(dev);
        DMAbuf_reset(dev);
        spin_lock_irq(&dmap->lock);
        dmap->dma_mode = DMODE_NONE;
    }
    if (!dmap->dma_mode) {
        reorganize_buffers(dev, dmap, 1);
        if ((err = adev->d->prepare_for_input(dev,
                dmap->fragment_size, dmap->nbufs)) < 0)
            return err;
        dmap->dma_mode = DMODE_INPUT;
    }
    if (!(dmap->flags & DMA_ACTIVE)) {
        if (dmap->needs_reorg)
            reorganize_buffers(dev, dmap, 0);
        local_start_dma(adev, dmap->raw_buf_phys, dmap->bytes_in_use, DMA_MODE_READ);
        adev->d->start_input(dev, dmap->raw_buf_phys + dmap->qtail * dmap->fragment_size,
                     dmap->fragment_size, 0);
        dmap->flags |= DMA_ACTIVE;
        if (adev->d->trigger)
            adev->d->trigger(dev, adev->enable_bits * adev->go);
    }
    return 0;
}
/* acquires lock */
int DMAbuf_getrdbuffer(int dev, char **buf, int *len, int dontblock)
{
    struct audio_operations *adev = audio_devs[dev];
    unsigned long flags;
    int err = 0, n = 0;
    struct dma_buffparms *dmap = adev->dmap_in;
    int go;

    if (!(adev->open_mode & OPEN_READ))
        return -EIO;
    spin_lock_irqsave(&dmap->lock,flags);
    if (dmap->needs_reorg)
        reorganize_buffers(dev, dmap, 0);
    if (adev->dmap_in->mapping_flags & DMA_MAP_MAPPED) {
/*        printk(KERN_WARNING "Sound: Can't read from mmapped device (1)\n");*/
          spin_unlock_irqrestore(&dmap->lock,flags);
          return -EINVAL;
    } else while (dmap->qlen <= 0 && n++ < 10) {
        long timeout = MAX_SCHEDULE_TIMEOUT;
        if (!(adev->enable_bits & PCM_ENABLE_INPUT) || !adev->go) {
            spin_unlock_irqrestore(&dmap->lock,flags);
            return -EAGAIN;
        }
        if ((err = DMAbuf_activate_recording(dev, dmap)) < 0) {
            spin_unlock_irqrestore(&dmap->lock,flags);
            return err;
        }
        /* Wait for the next block */

        if (dontblock) {
            spin_unlock_irqrestore(&dmap->lock,flags);
            return -EAGAIN;
        }
        if ((go = adev->go))
            timeout = dmabuf_timeout(dmap);

        spin_unlock_irqrestore(&dmap->lock,flags);
        timeout = interruptible_sleep_on_timeout(&adev->in_sleeper,
                             timeout);
        if (!timeout) {
            /* FIXME: include device name */
            err = -EIO;
            printk(KERN_WARNING "Sound: DMA (input) timed out - IRQ/DRQ config error?\n");
            dma_reset_input(dev);
        } else
            err = -EINTR;
        spin_lock_irqsave(&dmap->lock,flags);
    }
    spin_unlock_irqrestore(&dmap->lock,flags);

    if (dmap->qlen <= 0)
        return err ? err : -EINTR;
    *buf = &dmap->raw_buf[dmap->qhead * dmap->fragment_size + dmap->counts[dmap->qhead]];
    *len = dmap->fragment_size - dmap->counts[dmap->qhead];

    return dmap->qhead;
}

int DMAbuf_rmchars(int dev, int buff_no, int c)
{
    struct audio_operations *adev = audio_devs[dev];
    struct dma_buffparms *dmap = adev->dmap_in;
    int p = dmap->counts[dmap->qhead] + c;

    if (dmap->mapping_flags & DMA_MAP_MAPPED)
    {
/*        printk("Sound: Can't read from mmapped device (2)\n");*/
        return -EINVAL;
    }
    else if (dmap->qlen <= 0)
        return -EIO;
    else if (p >= dmap->fragment_size) {  /* This buffer is completely empty */
        dmap->counts[dmap->qhead] = 0;
        dmap->qlen--;
        dmap->qhead = (dmap->qhead + 1) % dmap->nbufs;
    }
    else dmap->counts[dmap->qhead] = p;

    return 0;
}
/* MUST be called with dmap->lock hold */
int DMAbuf_get_buffer_pointer(int dev, struct dma_buffparms *dmap, int direction)
{
    /*
     *  Try to approximate the active byte position of the DMA pointer within the
     *  buffer area as well as possible.
     */

    int pos;
    unsigned long f;

    if (!(dmap->flags & DMA_ACTIVE))
        pos = 0;
    else {
        int chan = dmap->dma;
        
        f=claim_dma_lock();
        clear_dma_ff(chan);
        
        if(!isa_dma_bridge_buggy)
            disable_dma(dmap->dma);
        
        pos = get_dma_residue(chan);
        
        pos = dmap->bytes_in_use - pos;

        if (!(dmap->mapping_flags & DMA_MAP_MAPPED)) {
            if (direction == DMODE_OUTPUT) {
                if (dmap->qhead == 0)
                    if (pos > dmap->fragment_size)
                        pos = 0;
            } else {
                if (dmap->qtail == 0)
                    if (pos > dmap->fragment_size)
                        pos = 0;
            }
        }
        if (pos < 0)
            pos = 0;
        if (pos >= dmap->bytes_in_use)
            pos = 0;
        
        if(!isa_dma_bridge_buggy)
            enable_dma(dmap->dma);
            
        release_dma_lock(f);
    }
    /* printk( "%04x ",  pos); */

    return pos;
}

/*
 *  DMAbuf_start_devices() is called by the /dev/music driver to start
 *  one or more audio devices at desired moment.
 */

void DMAbuf_start_devices(unsigned int devmask)
{
    struct audio_operations *adev;
    int dev;

    for (dev = 0; dev < num_audiodevs; dev++) {
        if (!(devmask & (1 << dev)))
            continue;
        if (!(adev = audio_devs[dev]))
            continue;
        if (adev->open_mode == 0)
            continue;
        if (adev->go)
            continue;
        /* OK to start the device */
        adev->go = 1;
        if (adev->d->trigger)
            adev->d->trigger(dev,adev->enable_bits * adev->go);
    }
}
/* via poll called without a lock ?*/
int DMAbuf_space_in_queue(int dev)
{
    struct audio_operations *adev = audio_devs[dev];
    int len, max, tmp;
    struct dma_buffparms *dmap = adev->dmap_out;
    int lim = dmap->nbufs;

    if (lim < 2)
        lim = 2;

    if (dmap->qlen >= lim)  /* No space at all */
        return 0;

    /*
     *  Verify that there are no more pending buffers than the limit
     *  defined by the process.
     */

    max = dmap->max_fragments;
    if (max > lim)
        max = lim;
    len = dmap->qlen;

    if (adev->d->local_qlen) {
        tmp = adev->d->local_qlen(dev);
        if (tmp && len)
            tmp--;  /* This buffer has been counted twice */
        len += tmp;
    }
    if (dmap->byte_counter % dmap->fragment_size)   /* There is a partial fragment */
        len = len + 1;

    if (len >= max)
        return 0;
    return max - len;
}
/* MUST not hold the spinlock  - this function may sleep */
static int output_sleep(int dev, int dontblock)
{
    struct audio_operations *adev = audio_devs[dev];
    int err = 0;
    struct dma_buffparms *dmap = adev->dmap_out;
    long timeout;
    long timeout_value;

    if (dontblock)
        return -EAGAIN;
    if (!(adev->enable_bits & PCM_ENABLE_OUTPUT))
        return -EAGAIN;

    /*
     * Wait for free space
     */
    if (signal_pending(current))
        return -EINTR;
    timeout = (adev->go && !(dmap->flags & DMA_NOTIMEOUT));
    if (timeout) 
        timeout_value = dmabuf_timeout(dmap);
    else
        timeout_value = MAX_SCHEDULE_TIMEOUT;
    timeout_value = interruptible_sleep_on_timeout(&adev->out_sleeper,
                               timeout_value);
    if (timeout != MAX_SCHEDULE_TIMEOUT && !timeout_value) {
        printk(KERN_WARNING "Sound: DMA (output) timed out - IRQ/DRQ config error?\n");
        dma_reset_output(dev);
    } else {
        if (signal_pending(current))
            err = -EINTR;
    }
    return err;
}
/* called with the lock held */
static int find_output_space(int dev, char **buf, int *size)
{
    struct audio_operations *adev = audio_devs[dev];
    struct dma_buffparms *dmap = adev->dmap_out;
    unsigned long active_offs;
    long len, offs;
    int maxfrags;
    int occupied_bytes = (dmap->user_counter % dmap->fragment_size);

    *buf = dmap->raw_buf;
    if (!(maxfrags = DMAbuf_space_in_queue(dev)) && !occupied_bytes)
        return 0;

#ifdef BE_CONSERVATIVE
    active_offs = dmap->byte_counter + dmap->qhead * dmap->fragment_size;
#else
    active_offs = max(DMAbuf_get_buffer_pointer(dev, dmap, DMODE_OUTPUT), 0);
    /* Check for pointer wrapping situation */
    if (active_offs >= dmap->bytes_in_use)
        active_offs = 0;
    active_offs += dmap->byte_counter;
#endif

    offs = (dmap->user_counter % dmap->bytes_in_use) & ~SAMPLE_ROUNDUP;
    if (offs < 0 || offs >= dmap->bytes_in_use) {
        printk(KERN_ERR "Sound: Got unexpected offs %ld. Giving up.\n", offs);
        printk("Counter = %ld, bytes=%d\n", dmap->user_counter, dmap->bytes_in_use);
        return 0;
    }
    *buf = dmap->raw_buf + offs;

    len = active_offs + dmap->bytes_in_use - dmap->user_counter;    /* Number of unused bytes in buffer */

    if ((offs + len) > dmap->bytes_in_use)
        len = dmap->bytes_in_use - offs;
    if (len < 0) {
        return 0;
    }
    if (len > ((maxfrags * dmap->fragment_size) - occupied_bytes))
        len = (maxfrags * dmap->fragment_size) - occupied_bytes;
    *size = len & ~SAMPLE_ROUNDUP;
    return (*size > 0);
}
/* acquires lock  */
int DMAbuf_getwrbuffer(int dev, char **buf, int *size, int dontblock)
{
    struct audio_operations *adev = audio_devs[dev];
    unsigned long flags;
    int err = -EIO;
    struct dma_buffparms *dmap = adev->dmap_out;

    if (dmap->mapping_flags & DMA_MAP_MAPPED) {
/*      printk(KERN_DEBUG "Sound: Can't write to mmapped device (3)\n");*/
        return -EINVAL;
    }
    spin_lock_irqsave(&dmap->lock,flags);
    if (dmap->needs_reorg)
        reorganize_buffers(dev, dmap, 0);

    if (dmap->dma_mode == DMODE_INPUT) {    /* Direction change */
        spin_unlock_irqrestore(&dmap->lock,flags);
        DMAbuf_reset(dev);
        spin_lock_irqsave(&dmap->lock,flags);
    }
    dmap->dma_mode = DMODE_OUTPUT;

    while (find_output_space(dev, buf, size) <= 0) {
        spin_unlock_irqrestore(&dmap->lock,flags);
        if ((err = output_sleep(dev, dontblock)) < 0) {
            return err;
        }
        spin_lock_irqsave(&dmap->lock,flags);
    }

    spin_unlock_irqrestore(&dmap->lock,flags);
    return 0;
}
/* has to acquire dmap->lock */
int DMAbuf_move_wrpointer(int dev, int l)
{
    struct audio_operations *adev = audio_devs[dev];
    struct dma_buffparms *dmap = adev->dmap_out;
    unsigned long ptr;
    unsigned long end_ptr, p;
    int post;
    unsigned long flags;

    spin_lock_irqsave(&dmap->lock,flags);
    post= (dmap->flags & DMA_POST);
    ptr = (dmap->user_counter / dmap->fragment_size) * dmap->fragment_size;

    dmap->flags &= ~DMA_POST;
    dmap->cfrag = -1;
    dmap->user_counter += l;
    dmap->flags |= DMA_DIRTY;

    if (dmap->byte_counter >= dmap->max_byte_counter) {
        /* Wrap the byte counters */
        long decr = dmap->byte_counter;
        dmap->byte_counter = (dmap->byte_counter % dmap->bytes_in_use);
        decr -= dmap->byte_counter;
        dmap->user_counter -= decr;
    }
    end_ptr = (dmap->user_counter / dmap->fragment_size) * dmap->fragment_size;

    p = (dmap->user_counter - 1) % dmap->bytes_in_use;
    dmap->neutral_byte = dmap->raw_buf[p];

    /* Update the fragment based bookkeeping too */
    while (ptr < end_ptr) {
        dmap->counts[dmap->qtail] = dmap->fragment_size;
        dmap->qtail = (dmap->qtail + 1) % dmap->nbufs;
        dmap->qlen++;
        ptr += dmap->fragment_size;
    }

    dmap->counts[dmap->qtail] = dmap->user_counter - ptr;

    /*
     *  Let the low level driver perform some postprocessing to
     *  the written data.
     */
    if (adev->d->postprocess_write)
        adev->d->postprocess_write(dev);

    if (!(dmap->flags & DMA_ACTIVE))
        if (dmap->qlen > 1 || (dmap->qlen > 0 && (post || dmap->qlen >= dmap->nbufs - 1)))
            DMAbuf_launch_output(dev, dmap);

    spin_unlock_irqrestore(&dmap->lock,flags);
    return 0;
}

int DMAbuf_start_dma(int dev, unsigned long physaddr, int count, int dma_mode)
{
    struct audio_operations *adev = audio_devs[dev];
    struct dma_buffparms *dmap = (dma_mode == DMA_MODE_WRITE) ? adev->dmap_out : adev->dmap_in;

    if (dmap->raw_buf == NULL) {
        printk(KERN_ERR "sound: DMA buffer(1) == NULL\n");
        printk("Device %d, chn=%s\n", dev, (dmap == adev->dmap_out) ? "out" : "in");
        return 0;
    }
    if (dmap->dma < 0)
        return 0;
    sound_start_dma(dmap, physaddr, count, dma_mode);
    return count;
}
EXPORT_SYMBOL(DMAbuf_start_dma);

static int local_start_dma(struct audio_operations *adev, unsigned long physaddr, int count, int dma_mode)
{
    struct dma_buffparms *dmap = (dma_mode == DMA_MODE_WRITE) ? adev->dmap_out : adev->dmap_in;

    if (dmap->raw_buf == NULL) {
        printk(KERN_ERR "sound: DMA buffer(2) == NULL\n");
        printk(KERN_ERR "Device %s, chn=%s\n", adev->name, (dmap == adev->dmap_out) ? "out" : "in");
        return 0;
    }
    if (dmap->flags & DMA_NODMA)
        return 1;
    if (dmap->dma < 0)
        return 0;
    sound_start_dma(dmap, dmap->raw_buf_phys, dmap->bytes_in_use, dma_mode | DMA_AUTOINIT);
    dmap->flags |= DMA_STARTED;
    return count;
}

static void finish_output_interrupt(int dev, struct dma_buffparms *dmap)
{
    struct audio_operations *adev = audio_devs[dev];

    if (dmap->audio_callback != NULL)
        dmap->audio_callback(dev, dmap->callback_parm);
    wake_up(&adev->out_sleeper);
    wake_up(&adev->poll_sleeper);
}
/* called with dmap->lock held in irq context*/
static void do_outputintr(int dev, int dummy)
{
    struct audio_operations *adev = audio_devs[dev];
    struct dma_buffparms *dmap = adev->dmap_out;
    int this_fragment;

    if (dmap->raw_buf == NULL) {
        printk(KERN_ERR "Sound: Error. Audio interrupt (%d) after freeing buffers.\n", dev);
        return;
    }
    if (dmap->mapping_flags & DMA_MAP_MAPPED) { /* Virtual memory mapped access */
        /* mmapped access */
        dmap->qhead = (dmap->qhead + 1) % dmap->nbufs;
        if (dmap->qhead == 0) {     /* Wrapped */
            dmap->byte_counter += dmap->bytes_in_use;
            if (dmap->byte_counter >= dmap->max_byte_counter) { /* Overflow */
                long decr = dmap->byte_counter;
                dmap->byte_counter = (dmap->byte_counter % dmap->bytes_in_use);
                decr -= dmap->byte_counter;
                dmap->user_counter -= decr;
            }
        }
        dmap->qlen++;   /* Yes increment it (don't decrement) */
        if (!(adev->flags & DMA_AUTOMODE))
            dmap->flags &= ~DMA_ACTIVE;
        dmap->counts[dmap->qhead] = dmap->fragment_size;
        DMAbuf_launch_output(dev, dmap);
        finish_output_interrupt(dev, dmap);
        return;
    }

    dmap->qlen--;
    this_fragment = dmap->qhead;
    dmap->qhead = (dmap->qhead + 1) % dmap->nbufs;

    if (dmap->qhead == 0) { /* Wrapped */
        dmap->byte_counter += dmap->bytes_in_use;
        if (dmap->byte_counter >= dmap->max_byte_counter) { /* Overflow */
            long decr = dmap->byte_counter;
            dmap->byte_counter = (dmap->byte_counter % dmap->bytes_in_use);
            decr -= dmap->byte_counter;
            dmap->user_counter -= decr;
        }
    }
    if (!(adev->flags & DMA_AUTOMODE))
        dmap->flags &= ~DMA_ACTIVE;
        
    /*
     *  This is  dmap->qlen <= 0 except when closing when
     *  dmap->qlen < 0
     */
     
    while (dmap->qlen <= -dmap->closing) {
        dmap->underrun_count++;
        dmap->qlen++;
        if ((dmap->flags & DMA_DIRTY) && dmap->applic_profile != APF_CPUINTENS) {
            dmap->flags &= ~DMA_DIRTY;
            memset(adev->dmap_out->raw_buf, adev->dmap_out->neutral_byte,
                   adev->dmap_out->buffsize);
        }
        dmap->user_counter += dmap->fragment_size;
        dmap->qtail = (dmap->qtail + 1) % dmap->nbufs;
    }
    if (dmap->qlen > 0)
        DMAbuf_launch_output(dev, dmap);
    finish_output_interrupt(dev, dmap);
}
/* called in irq context */
void DMAbuf_outputintr(int dev, int notify_only)
{
    struct audio_operations *adev = audio_devs[dev];
    unsigned long flags;
    struct dma_buffparms *dmap = adev->dmap_out;

    spin_lock_irqsave(&dmap->lock,flags);
    if (!(dmap->flags & DMA_NODMA)) {
        int chan = dmap->dma, pos, n;
        unsigned long f;
        
        f=claim_dma_lock();
        
        if(!isa_dma_bridge_buggy)
            disable_dma(dmap->dma);
        clear_dma_ff(chan);
        pos = dmap->bytes_in_use - get_dma_residue(chan);
        if(!isa_dma_bridge_buggy)
            enable_dma(dmap->dma);
        release_dma_lock(f);
        
        pos = pos / dmap->fragment_size;    /* Actual qhead */
        if (pos < 0 || pos >= dmap->nbufs)
            pos = 0;
        n = 0;
        while (dmap->qhead != pos && n++ < dmap->nbufs)
            do_outputintr(dev, notify_only);
    }
    else
        do_outputintr(dev, notify_only);
    spin_unlock_irqrestore(&dmap->lock,flags);
}
EXPORT_SYMBOL(DMAbuf_outputintr);

/* called with dmap->lock held in irq context */
static void do_inputintr(int dev)
{
    struct audio_operations *adev = audio_devs[dev];
    struct dma_buffparms *dmap = adev->dmap_in;

    if (dmap->raw_buf == NULL) {
        printk(KERN_ERR "Sound: Fatal error. Audio interrupt after freeing buffers.\n");
        return;
    }
    if (dmap->mapping_flags & DMA_MAP_MAPPED) {
        dmap->qtail = (dmap->qtail + 1) % dmap->nbufs;
        if (dmap->qtail == 0) {     /* Wrapped */
            dmap->byte_counter += dmap->bytes_in_use;
            if (dmap->byte_counter >= dmap->max_byte_counter) { /* Overflow */
                long decr = dmap->byte_counter;
                dmap->byte_counter = (dmap->byte_counter % dmap->bytes_in_use) + dmap->bytes_in_use;
                decr -= dmap->byte_counter;
                dmap->user_counter -= decr;
            }
        }
        dmap->qlen++;

        if (!(adev->flags & DMA_AUTOMODE)) {
            if (dmap->needs_reorg)
                reorganize_buffers(dev, dmap, 0);
            local_start_dma(adev, dmap->raw_buf_phys, dmap->bytes_in_use,DMA_MODE_READ);
            adev->d->start_input(dev, dmap->raw_buf_phys + dmap->qtail * dmap->fragment_size,
                         dmap->fragment_size, 1);
            if (adev->d->trigger)
                adev->d->trigger(dev, adev->enable_bits * adev->go);
        }
        dmap->flags |= DMA_ACTIVE;
    } else if (dmap->qlen >= (dmap->nbufs - 1)) {
        printk(KERN_WARNING "Sound: Recording overrun\n");
        dmap->underrun_count++;

        /* Just throw away the oldest fragment but keep the engine running */
        dmap->qhead = (dmap->qhead + 1) % dmap->nbufs;
        dmap->qtail = (dmap->qtail + 1) % dmap->nbufs;
    } else if (dmap->qlen >= 0 && dmap->qlen < dmap->nbufs) {
        dmap->qlen++;
        dmap->qtail = (dmap->qtail + 1) % dmap->nbufs;
        if (dmap->qtail == 0) {     /* Wrapped */
            dmap->byte_counter += dmap->bytes_in_use;
            if (dmap->byte_counter >= dmap->max_byte_counter) { /* Overflow */
                long decr = dmap->byte_counter;
                dmap->byte_counter = (dmap->byte_counter % dmap->bytes_in_use) + dmap->bytes_in_use;
                decr -= dmap->byte_counter;
                dmap->user_counter -= decr;
            }
        }
    }
    if (!(adev->flags & DMA_AUTOMODE) || (dmap->flags & DMA_NODMA)) {
        local_start_dma(adev, dmap->raw_buf_phys, dmap->bytes_in_use, DMA_MODE_READ);
        adev->d->start_input(dev, dmap->raw_buf_phys + dmap->qtail * dmap->fragment_size, dmap->fragment_size, 1);
        if (adev->d->trigger)
            adev->d->trigger(dev,adev->enable_bits * adev->go);
    }
    dmap->flags |= DMA_ACTIVE;
    if (dmap->qlen > 0)
    {
        wake_up(&adev->in_sleeper);
        wake_up(&adev->poll_sleeper);
    }
}
/* called in irq context */
void DMAbuf_inputintr(int dev)
{
    struct audio_operations *adev = audio_devs[dev];
    struct dma_buffparms *dmap = adev->dmap_in;
    unsigned long flags;

    spin_lock_irqsave(&dmap->lock,flags);

    if (!(dmap->flags & DMA_NODMA)) {
        int chan = dmap->dma, pos, n;
        unsigned long f;
        
        f=claim_dma_lock();
        if(!isa_dma_bridge_buggy)
            disable_dma(dmap->dma);
        clear_dma_ff(chan);
        pos = dmap->bytes_in_use - get_dma_residue(chan);
        if(!isa_dma_bridge_buggy)
            enable_dma(dmap->dma);
        release_dma_lock(f);

        pos = pos / dmap->fragment_size;    /* Actual qhead */
        if (pos < 0 || pos >= dmap->nbufs)
            pos = 0;

        n = 0;
        while (dmap->qtail != pos && ++n < dmap->nbufs)
            do_inputintr(dev);
    } else
        do_inputintr(dev);
    spin_unlock_irqrestore(&dmap->lock,flags);
}
EXPORT_SYMBOL(DMAbuf_inputintr);

void DMAbuf_init(int dev, int dma1, int dma2)
{
    struct audio_operations *adev = audio_devs[dev];
    /*
     * NOTE! This routine could be called several times.
     */

    if (adev && adev->dmap_out == NULL) {
        if (adev->d == NULL)
            panic("OSS: audio_devs[%d]->d == NULL\n", dev);

        if (adev->parent_dev) {  /* Use DMA map of the parent dev */
            int parent = adev->parent_dev - 1;
            adev->dmap_out = audio_devs[parent]->dmap_out;
            adev->dmap_in = audio_devs[parent]->dmap_in;
        } else {
            adev->dmap_out = adev->dmap_in = &adev->dmaps[0];
            adev->dmap_out->dma = dma1;
            if (adev->flags & DMA_DUPLEX) {
                adev->dmap_in = &adev->dmaps[1];
                adev->dmap_in->dma = dma2;
            }
        }
        /* Persistent DMA buffers allocated here */
        if (sound_dmap_flag == DMAP_KEEP_ON_CLOSE) {
            if (adev->dmap_in->raw_buf == NULL)
                sound_alloc_dmap(adev->dmap_in);
            if (adev->dmap_out->raw_buf == NULL)
                sound_alloc_dmap(adev->dmap_out);
        }
    }
}

/* No kernel lock - DMAbuf_activate_recording protected by global cli/sti */
static unsigned int poll_input(struct file * file, int dev, poll_table *wait)
{
    struct audio_operations *adev = audio_devs[dev];
    struct dma_buffparms *dmap = adev->dmap_in;

    if (!(adev->open_mode & OPEN_READ))
        return 0;
    if (dmap->mapping_flags & DMA_MAP_MAPPED) {
        if (dmap->qlen)
            return POLLIN | POLLRDNORM;
        return 0;
    }
    if (dmap->dma_mode != DMODE_INPUT) {
        if (dmap->dma_mode == DMODE_NONE &&
            adev->enable_bits & PCM_ENABLE_INPUT &&
            !dmap->qlen && adev->go) {
            unsigned long flags;
            
            spin_lock_irqsave(&dmap->lock,flags);
            DMAbuf_activate_recording(dev, dmap);
            spin_unlock_irqrestore(&dmap->lock,flags);
        }
        return 0;
    }
    if (!dmap->qlen)
        return 0;
    return POLLIN | POLLRDNORM;
}

static unsigned int poll_output(struct file * file, int dev, poll_table *wait)
{
    struct audio_operations *adev = audio_devs[dev];
    struct dma_buffparms *dmap = adev->dmap_out;
    
    if (!(adev->open_mode & OPEN_WRITE))
        return 0;
    if (dmap->mapping_flags & DMA_MAP_MAPPED) {
        if (dmap->qlen)
            return POLLOUT | POLLWRNORM;
        return 0;
    }
    if (dmap->dma_mode == DMODE_INPUT)
        return 0;
    if (dmap->dma_mode == DMODE_NONE)
        return POLLOUT | POLLWRNORM;
    if (!DMAbuf_space_in_queue(dev))
        return 0;
    return POLLOUT | POLLWRNORM;
}

unsigned int DMAbuf_poll(struct file * file, int dev, poll_table *wait)
{
    struct audio_operations *adev = audio_devs[dev];
    poll_wait(file, &adev->poll_sleeper, wait);
    return poll_input(file, dev, wait) | poll_output(file, dev, wait);
}

void DMAbuf_deinit(int dev)
{
    struct audio_operations *adev = audio_devs[dev];
    /* This routine is called when driver is being unloaded */
    if (!adev)
        return;

    /* Persistent DMA buffers deallocated here */
    if (sound_dmap_flag == DMAP_KEEP_ON_CLOSE) {
        sound_free_dmap(adev->dmap_out);
        if (adev->flags & DMA_DUPLEX)
            sound_free_dmap(adev->dmap_in);
    }
}