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dmabuf.c

/*
 * 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 "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 = 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);
}
/* 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);
      }
}

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