dmasound_core.c

linux-2.6.15.6

	sq->locked = 1 ; /* don't think we have a race prob. here _check_ */

	/* make sure that the parameters are set up
	   This should have been done already...
	*/

	dmasound.mach.init();

	/* OK.  If the user has set fragment parameters explicitly, then we
	   should leave them alone... as long as they are valid.
	   Invalid user fragment params can occur if we allow the whole buffer
	   to be used when the user requests the fragments sizes (with no soft
	   x-lation) and then the user subsequently sets a soft x-lation that
	   requires increased internal buffering.

	   Othwerwise (if the user did not set them) OSS says that we should
	   select frag params on the basis of 0.5 s output & 0.1 s input
	   latency. (TODO.  For now we will copy in the defaults.)
	*/

	if (sq->user_frags <= 0) {
		sq->max_count = sq->numBufs ;
		sq->max_active = sq->numBufs ;
		sq->block_size = sq->bufSize;
		/* set up the user info */
		sq->user_frags = sq->numBufs ;
		sq->user_frag_size = sq->bufSize ;
		sq->user_frag_size *=
			(dmasound.soft.size * (dmasound.soft.stereo+1) ) ;
		sq->user_frag_size /=
			(dmasound.hard.size * (dmasound.hard.stereo+1) ) ;
	} else {
		/* work out requested block size */
		sq->block_size = sq->user_frag_size ;
		sq->block_size *=
			(dmasound.hard.size * (dmasound.hard.stereo+1) ) ;
		sq->block_size /=
			(dmasound.soft.size * (dmasound.soft.stereo+1) ) ;
		/* the user wants to write frag-size chunks */
		sq->block_size *= dmasound.hard.speed ;
		sq->block_size /= dmasound.soft.speed ;
		/* this only works for size values which are powers of 2 */
		hard_frame =
			(dmasound.hard.size * (dmasound.hard.stereo+1))/8 ;
		sq->block_size +=  (hard_frame - 1) ;
		sq->block_size &= ~(hard_frame - 1) ; /* make sure we are aligned */
		/* let's just check for obvious mistakes */
		if ( sq->block_size <= 0 || sq->block_size > sq->bufSize) {
#ifdef DEBUG_DMASOUND
printk("dmasound_core: invalid frag size (user set %d)\n", sq->user_frag_size) ;
#endif
			sq->block_size = sq->bufSize ;
		}
		if ( sq->user_frags <= sq->numBufs ) {
			sq->max_count = sq->user_frags ;
			/* if user has set max_active - then use it */
			sq->max_active = (sq->max_active <= sq->max_count) ?
				sq->max_active : sq->max_count ;
		} else {
#ifdef DEBUG_DMASOUND
printk("dmasound_core: invalid frag count (user set %d)\n", sq->user_frags) ;
#endif
			sq->max_count =
			sq->max_active = sq->numBufs ;
		}
	}
	sq->front = sq->count = sq->rear_size = 0;
	sq->syncing = 0;
	sq->active = 0;

	if (sq == &write_sq) {
	    sq->rear = -1;
	    setup_func = dmasound.mach.write_sq_setup;
	}
#ifdef HAS_RECORD
	else {
	    sq->rear = 0;
	    setup_func = dmasound.mach.read_sq_setup;
	}
#endif
	if (setup_func)
	    return setup_func();
	return 0 ;
}

static inline void sq_play(void)
{
	dmasound.mach.play();
}

static ssize_t sq_write(struct file *file, const char __user *src, size_t uLeft,
			loff_t *ppos)
{
	ssize_t uWritten = 0;
	u_char *dest;
	ssize_t uUsed = 0, bUsed, bLeft;
	unsigned long flags ;

	/* ++TeSche: Is something like this necessary?
	 * Hey, that's an honest question! Or does any other part of the
	 * filesystem already checks this situation? I really don't know.
	 */
	if (uLeft == 0)
		return 0;

	/* implement any changes we have made to the soft/hard params.
	   this is not satisfactory really, all we have done up to now is to
	   say what we would like - there hasn't been any real checking of capability
	*/

	if (shared_resources_initialised == 0) {
		dmasound.mach.init() ;
		shared_resources_initialised = 1 ;
	}

	/* set up the sq if it is not already done. This may seem a dumb place
	   to do it - but it is what OSS requires.  It means that write() can
	   return memory allocation errors.  To avoid this possibility use the
	   GETBLKSIZE or GETOSPACE ioctls (after you've fiddled with all the
	   params you want to change) - these ioctls also force the setup.
	*/

	if (write_sq.locked == 0) {
		if ((uWritten = sq_setup(&write_sq)) < 0) return uWritten ;
		uWritten = 0 ;
	}

/* FIXME: I think that this may be the wrong behaviour when we get strapped
	for time and the cpu is close to being (or actually) behind in sending data.
	- because we've lost the time that the N samples, already in the buffer,
	would have given us to get here with the next lot from the user.
*/
	/* The interrupt doesn't start to play the last, incomplete frame.
	 * Thus we can append to it without disabling the interrupts! (Note
	 * also that write_sq.rear isn't affected by the interrupt.)
	 */

	/* as of 1.6 this behaviour changes if SNDCTL_DSP_POST has been issued:
	   this will mimic the behaviour of syncing and allow the sq_play() to
	   queue a partial fragment.  Since sq_play() may/will be called from
	   the IRQ handler - at least on Pmac we have to deal with it.
	   The strategy - possibly not optimum - is to kill _POST status if we
	   get here.  This seems, at least, reasonable - in the sense that POST
	   is supposed to indicate that we might not write before the queue
	   is drained - and if we get here in time then it does not apply.
	*/

	spin_lock_irqsave(&dmasound.lock, flags);
	write_sq.syncing &= ~2 ; /* take out POST status */
	spin_unlock_irqrestore(&dmasound.lock, flags);

	if (write_sq.count > 0 &&
	    (bLeft = write_sq.block_size-write_sq.rear_size) > 0) {
		dest = write_sq.buffers[write_sq.rear];
		bUsed = write_sq.rear_size;
		uUsed = sound_copy_translate(dmasound.trans_write, src, uLeft,
					     dest, &bUsed, bLeft);
		if (uUsed <= 0)
			return uUsed;
		src += uUsed;
		uWritten += uUsed;
		uLeft = (uUsed <= uLeft) ? (uLeft - uUsed) : 0 ; /* paranoia */
		write_sq.rear_size = bUsed;
	}

	while (uLeft) {
		while (write_sq.count >= write_sq.max_active) {
			sq_play();
			if (write_sq.open_mode & O_NONBLOCK)
				return uWritten > 0 ? uWritten : -EAGAIN;
			SLEEP(write_sq.action_queue);
			if (signal_pending(current))
				return uWritten > 0 ? uWritten : -EINTR;
		}

		/* Here, we can avoid disabling the interrupt by first
		 * copying and translating the data, and then updating
		 * the write_sq variables. Until this is done, the interrupt
		 * won't see the new frame and we can work on it
		 * undisturbed.
		 */

		dest = write_sq.buffers[(write_sq.rear+1) % write_sq.max_count];
		bUsed = 0;
		bLeft = write_sq.block_size;
		uUsed = sound_copy_translate(dmasound.trans_write, src, uLeft,
					     dest, &bUsed, bLeft);
		if (uUsed <= 0)
			break;
		src += uUsed;
		uWritten += uUsed;
		uLeft = (uUsed <= uLeft) ? (uLeft - uUsed) : 0 ; /* paranoia */
		if (bUsed) {
			write_sq.rear = (write_sq.rear+1) % write_sq.max_count;
			write_sq.rear_size = bUsed;
			write_sq.count++;
		}
	} /* uUsed may have been 0 */

	sq_play();

	return uUsed < 0? uUsed: uWritten;
}

static unsigned int sq_poll(struct file *file, struct poll_table_struct *wait)
{
	unsigned int mask = 0;
	int retVal;
	
	if (write_sq.locked == 0) {
		if ((retVal = sq_setup(&write_sq)) < 0)
			return retVal;
		return 0;
	}
	if (file->f_mode & FMODE_WRITE )
		poll_wait(file, &write_sq.action_queue, wait);
#ifdef HAS_RECORD
	if (file->f_mode & FMODE_READ)
		poll_wait(file, &read_sq.action_queue, wait);
	if (file->f_mode & FMODE_READ)
		if (read_sq.block_size - read_sq.rear_size > 0)
			mask |= POLLIN | POLLRDNORM;
#endif
	if (file->f_mode & FMODE_WRITE)
		if (write_sq.count < write_sq.max_active || write_sq.block_size - write_sq.rear_size > 0)
			mask |= POLLOUT | POLLWRNORM;
	return mask;

}

#ifdef HAS_RECORD
    /*
     *  Here is how the values are used for reading.
     *  The value 'active' simply indicates the DMA is running.  This is done
     *  so the driver semantics are DMA starts when the first read is posted.
     *  The value 'front' indicates the buffer we should next send to the user.
     *  The value 'rear' indicates the buffer the DMA is currently filling.
     *  When 'front' == 'rear' the buffer "ring" is empty (we always have an
     *  empty available).  The 'rear_size' is used to track partial offsets
     *  into the buffer we are currently returning to the user.

     *  This level (> [1.5]) doesn't care what strategy the LL driver uses with
     *  DMA on over-run.  It can leave it running (and keep active == 1) or it
     *  can kill it and set active == 0 in which case this routine will spot
     *  it and restart the DMA.
     */

static ssize_t sq_read(struct file *file, char __user *dst, size_t uLeft,
		       loff_t *ppos)
{

	ssize_t	uRead, bLeft, bUsed, uUsed;

	if (uLeft == 0)
		return 0;

	/* cater for the compatibility mode - record compiled in but no LL */
	if (dmasound.mach.record == NULL)
		return -EINVAL ;

	/* see comment in sq_write()
	*/

	if( shared_resources_initialised == 0) {
		dmasound.mach.init() ;
		shared_resources_initialised = 1 ;
	}

	/* set up the sq if it is not already done. see comments in sq_write().
	*/

	if (read_sq.locked == 0) {
		if ((uRead = sq_setup(&read_sq)) < 0)
			return uRead ;
	}

	uRead = 0;

	/* Move what the user requests, depending upon other options.
	*/
	while (uLeft > 0) {

		/* we happened to get behind and the LL driver killed DMA
		   then we should set it going again.  This also sets it
		   going the first time through.
		*/
		if ( !read_sq.active )
			dmasound.mach.record();

		/* When front == rear, the DMA is not done yet.
		*/
		while (read_sq.front == read_sq.rear) {
			if (read_sq.open_mode & O_NONBLOCK) {
			       return uRead > 0 ? uRead : -EAGAIN;
			}
			SLEEP(read_sq.action_queue);
			if (signal_pending(current))
				return uRead > 0 ? uRead : -EINTR;
		}

		/* The amount we move is either what is left in the
		 * current buffer or what the user wants.
		 */
		bLeft = read_sq.block_size - read_sq.rear_size;
		bUsed = read_sq.rear_size;
		uUsed = sound_copy_translate(dmasound.trans_read, dst, uLeft,
					     read_sq.buffers[read_sq.front],
					     &bUsed, bLeft);
		if (uUsed <= 0)
			return uUsed;
		dst += uUsed;
		uRead += uUsed;
		uLeft -= uUsed;
		read_sq.rear_size += bUsed;
		if (read_sq.rear_size >= read_sq.block_size) {
			read_sq.rear_size = 0;
			read_sq.front++;
			if (read_sq.front >= read_sq.max_active)
				read_sq.front = 0;
		}
	}
	return uRead;
}
#endif /* HAS_RECORD */

static inline void sq_init_waitqueue(struct sound_queue *sq)
{
	init_waitqueue_head(&sq->action_queue);
	init_waitqueue_head(&sq->open_queue);
	init_waitqueue_head(&sq->sync_queue);
	sq->busy = 0;
}

#if 0 /* blocking open() */
static inline void sq_wake_up(struct sound_queue *sq, struct file *file,
			      mode_t mode)
{
	if (file->f_mode & mode) {
		sq->busy = 0; /* CHECK: IS THIS OK??? */
		WAKE_UP(sq->open_queue);
	}
}
#endif

static int sq_open2(struct sound_queue *sq, struct file *file, mode_t mode,
		    int numbufs, int bufsize)
{
	int rc = 0;

	if (file->f_mode & mode) {
		if (sq->busy) {
#if 0 /* blocking open() */
			rc = -EBUSY;
			if (file->f_flags & O_NONBLOCK)
				return rc;
			rc = -EINTR;
			while (sq->busy) {
				SLEEP(sq->open_queue);
				if (signal_pending(current))
					return rc;
			}
			rc = 0;
#else
			/* OSS manual says we will return EBUSY regardless
			   of O_NOBLOCK.
			*/
			return -EBUSY ;
#endif
		}
		sq->busy = 1; /* Let's play spot-the-race-condition */

		/* allocate the default number & size of buffers.
		   (i.e. specified in _setup() or as module params)
		   can't be changed at the moment - but _could_ be perhaps
		   in the setfragments ioctl.
		*/
		if (( rc = sq_allocate_buffers(sq, numbufs, bufsize))) {
#if 0 /* blocking open() */
			sq_wake_up(sq, file, mode);
#else
			sq->busy = 0 ;
#endif
			return rc;
		}

		sq->open_mode = file->f_mode;
	}
	return rc;
}

#define write_sq_init_waitqueue()	sq_init_waitqueue(&write_sq)
#if 0 /* blocking open() */
#define write_sq_wake_up(file)		sq_wake_up(&write_sq, file, FMODE_WRITE)
#endif
#define write_sq_release_buffers()	sq_release_buffers(&write_sq)
#define write_sq_open(file)	\
	sq_open2(&write_sq, file, FMODE_WRITE, numWriteBufs, writeBufSize )

#ifdef HAS_RECORD
#define read_sq_init_waitqueue()	sq_init_waitqueue(&read_sq)
#if 0 /* blocking open() */
#define read_sq_wake_up(file)		sq_wake_up(&read_sq, file, FMODE_READ)
#endif
#define read_sq_release_buffers()	sq_release_buffers(&read_sq)
#define read_sq_open(file)	\
	sq_open2(&read_sq, file, FMODE_READ, numReadBufs, readBufSize )
#else
#define read_sq_init_waitqueue()	do {} while (0)
#if 0 /* blocking open() */
#define read_sq_wake_up(file)		do {} while (0)
#endif
#define read_sq_release_buffers()	do {} while (0)
#define sq_reset_input()		do {} while (0)
#endif

static int sq_open(struct inode *inode, struct file *file)
{
	int rc;

	if (!try_module_get(dmasound.mach.owner))
		return -ENODEV;

	rc = write_sq_open(file); /* checks the f_mode */
	if (rc)
		goto out;
#ifdef HAS_RECORD
	if (dmasound.mach.record) {
		rc = read_sq_open(file); /* checks the f_mode */
		if (rc)
			goto out;
	} else { /* no record function installed; in compat mode */
		if (file->f_mode & FMODE_READ) {
			/* TODO: if O_RDWR, release any resources grabbed by write part */
			rc = -ENXIO;
			goto out;
		}
	}
#else /* !HAS_RECORD */
	if (file->f_mode & FMODE_READ) {
		/* TODO: if O_RDWR, release any resources grabbed by write part */
		rc = -ENXIO ; /* I think this is what is required by open(2) */
		goto out;
	}
#endif /* HAS_RECORD */

	if (dmasound.mach.sq_open)
	    dmasound.mach.sq_open(file->f_mode);

	/* CHECK whether this is sensible - in the case that dsp0 could be opened
	  O_RDONLY and dsp1 could be opened O_WRONLY
	*/

	dmasound.minDev = iminor(inode) & 0x0f;

	/* OK. - we should make some attempt at consistency. At least the H'ware
	   options should be set with a valid mode.  We will make it that the LL
	   driver must supply defaults for hard & soft params.
	*/