/*
 * sound/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 "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;
}
/* aquires 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 = DMAbuf_get_buffer_pointer(dev, dmap, DMODE_OUTPUT);
        /* Check for pointer wrapping situation */
        if (active_offs < 0 || 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);
}
/* aquires 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 aquire 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;
}

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);
}
/* 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);
}

int DMAbuf_open_dma(int dev)
{
        /*
         *    NOTE!  This routine opens only the primary DMA channel (output).
         */
        struct audio_operations *adev = audio_devs[dev];
        int err;

        if ((err = open_dmap(adev, OPEN_READWRITE, adev->dmap_out)) < 0)
                return -EBUSY;
        dma_init_buffers(adev->dmap_out);
        adev->dmap_out->flags |= DMA_ALLOC_DONE;
        adev->dmap_out->fragment_size = adev->dmap_out->buffsize;

        if (adev->dmap_out->dma >= 0) {
                unsigned long flags;

                flags=claim_dma_lock();
                clear_dma_ff(adev->dmap_out->dma);
                disable_dma(adev->dmap_out->dma);
                release_dma_lock(flags);
        }
        return 0;
}

void DMAbuf_close_dma(int dev)
{
        close_dmap(audio_devs[dev], audio_devs[dev]->dmap_out);
}

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

        /* drag in audio_syms.o */
        {
                extern char audio_syms_symbol;
                audio_syms_symbol = 0;
        }

        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);
        }
}