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Commit ae4e131e authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
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staging: comedi: das1800: introduce das1800_isadma_disable() 



Introduce a helper function to disable and the ISA DMA controller and
return the residue as described in Documentation/DMA-ISA-LPC.txt.

Signed-off-by: default avatarH Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: default avatarIan Abbott <abbotti@mev.co.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent dec3aa4f

drivers/staging/comedi/drivers/das1800.c

+18 −22
Original line number Diff line number Diff line
@@ -465,6 +465,19 @@ static void das1800_isadma_program(struct das1800_dma_desc *dma) 
	release_dma_lock(flags);

}



static unsigned int das1800_isadma_disable(unsigned int dma_chan)

{

	unsigned long flags;

	unsigned int residue;



	flags = claim_dma_lock();

	disable_dma(dma_chan);

	residue = get_dma_residue(dma_chan);

	release_dma_lock(flags);



	return residue;

}



static inline uint16_t munge_bipolar_sample(const struct comedi_device *dev,

					    uint16_t sample)

{
@@ -524,23 +537,16 @@ static void das1800_handle_fifo_not_empty(struct comedi_device *dev, 
	}

}



/* Utility function used by das1800_flush_dma() and das1800_handle_dma().

 * Assumes dma lock is held */

/* Utility function used by das1800_flush_dma() and das1800_handle_dma() */

static void das1800_flush_dma_channel(struct comedi_device *dev,

				      struct comedi_subdevice *s,

				      struct das1800_dma_desc *dma)

{

	unsigned int nbytes;

	unsigned int residue = das1800_isadma_disable(dma->chan);

	unsigned int nbytes = dma->size - residue;

	unsigned int nsamples;



	disable_dma(dma->chan);



	/* clear flip-flop to make sure 2-byte registers

	 * get set correctly */

	clear_dma_ff(dma->chan);



	/*  figure out how many points to read */

	nbytes = dma->size - get_dma_residue(dma->chan);

	nsamples = comedi_bytes_to_samples(s, nbytes);

	nsamples = comedi_nsamples_left(s, nsamples);
@@ -555,10 +561,8 @@ static void das1800_flush_dma(struct comedi_device *dev, 
{

	struct das1800_private *devpriv = dev->private;

	struct das1800_dma_desc *dma = &devpriv->dma_desc[devpriv->cur_dma];

	unsigned long flags;

	const int dual_dma = devpriv->irq_dma_bits & DMA_DUAL;



	flags = claim_dma_lock();

	das1800_flush_dma_channel(dev, s, dma);



	if (dual_dma) {
@@ -568,8 +572,6 @@ static void das1800_flush_dma(struct comedi_device *dev, 
		das1800_flush_dma_channel(dev, s, dma);

	}



	release_dma_lock(flags);



	/*  get any remaining samples in fifo */

	das1800_handle_fifo_not_empty(dev, s);

}
@@ -579,12 +581,9 @@ static void das1800_handle_dma(struct comedi_device *dev, 
{

	struct das1800_private *devpriv = dev->private;

	struct das1800_dma_desc *dma = &devpriv->dma_desc[devpriv->cur_dma];

	unsigned long flags;

	const int dual_dma = devpriv->irq_dma_bits & DMA_DUAL;



	flags = claim_dma_lock();

	das1800_flush_dma_channel(dev, s, dma);

	release_dma_lock(flags);



	/* re-enable dma channel */

	das1800_isadma_program(dma);
@@ -611,7 +610,7 @@ static int das1800_cancel(struct comedi_device *dev, struct comedi_subdevice *s) 
	for (i = 0; i < 2; i++) {

		dma = &devpriv->dma_desc[i];

		if (dma->chan)

			disable_dma(dma->chan);

			das1800_isadma_disable(dma->chan);

	}



	return 0;
@@ -1233,7 +1232,6 @@ static int das1800_init_dma(struct comedi_device *dev, 
	struct das1800_private *devpriv = dev->private;

	struct das1800_dma_desc *dma;

	unsigned int *dma_chan;

	unsigned long flags;

	int i;



	/*
@@ -1292,9 +1290,7 @@ static int das1800_init_dma(struct comedi_device *dev, 
		if (!dma->virt_addr)

			return -ENOMEM;



		flags = claim_dma_lock();

		disable_dma(dma->chan);

		release_dma_lock(flags);

		das1800_isadma_disable(dma->chan);

	}



	return 0;