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Commit 72ba5c16 authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
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staging: comedi: ni_labpc_isadma: tidy up labpc_drain_dma() 



Tidy up the code that determines the number of samples to read for the
current DMA transfer and how many samples are needed for the next DMA,

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 0f02b081

drivers/staging/comedi/drivers/ni_labpc_isadma.c

+24 −24
Original line number Original line Diff line number Diff line
@@ -105,12 +105,11 @@ void labpc_drain_dma(struct comedi_device *dev) 
	struct comedi_subdevice *s = dev->read_subdev;

	struct comedi_subdevice *s = dev->read_subdev;

	struct comedi_async *async = s->async;

	struct comedi_async *async = s->async;

	struct comedi_cmd *cmd = &async->cmd;

	struct comedi_cmd *cmd = &async->cmd;

	unsigned int sample_size = comedi_bytes_per_sample(s);

	unsigned int max_samples = comedi_bytes_to_samples(s, dma->size);

	int status;

	unsigned int residue;

	unsigned int nsamples;

	unsigned int leftover;

	unsigned long flags;

	unsigned long flags;

	unsigned int max_points, num_points, residue, leftover;



	status = devpriv->stat1;





	/*

	/*

	 * residue is the number of bytes left to be done on the dma

	 * residue is the number of bytes left to be done on the dma
@@ -119,32 +118,33 @@ void labpc_drain_dma(struct comedi_device *dev) 
	 */

	 */

	residue = labpc_isadma_disable(dma);

	residue = labpc_isadma_disable(dma);





	/* figure out how many points to read */

	/*

	max_points = dma->size / sample_size;

	 * Figure out how many samples to read for this transfer and

	num_points = max_points - comedi_bytes_to_samples(s, residue);

	 * how many will be stored for next time.

	if (cmd->stop_src == TRIG_COUNT && devpriv->count < num_points)

	 */

		num_points = devpriv->count;

	nsamples = max_samples - comedi_bytes_to_samples(s, residue);



	if (cmd->stop_src == TRIG_COUNT) {

	/* figure out how many points will be stored next time */

		if (devpriv->count <= nsamples) {

			nsamples = devpriv->count;

			leftover = 0;

			leftover = 0;

	if (cmd->stop_src != TRIG_COUNT) {

		} else {

		leftover = dma->size / sample_size;

			leftover = devpriv->count - nsamples;

	} else if (devpriv->count > num_points) {

			if (leftover > max_samples)

		leftover = devpriv->count - num_points;

				leftover = max_samples;

		if (leftover > max_points)

			leftover = max_points;

		}

		}

		devpriv->count -= nsamples;

	} else {

		leftover = max_samples;

	}

	dma->size = comedi_samples_to_bytes(s, leftover);





	comedi_buf_write_samples(s, dma->virt_addr, num_points);

	comedi_buf_write_samples(s, dma->virt_addr, nsamples);



	if (cmd->stop_src == TRIG_COUNT)

		devpriv->count -= num_points;





	/* set address and count for next transfer */

	/* set address and count for next transfer */

	flags = claim_dma_lock();

	flags = claim_dma_lock();

	set_dma_mode(dma->chan, DMA_MODE_READ);

	set_dma_mode(dma->chan, DMA_MODE_READ);

	set_dma_addr(dma->chan, dma->hw_addr);

	set_dma_addr(dma->chan, dma->hw_addr);

	set_dma_count(dma->chan, leftover * sample_size);

	set_dma_count(dma->chan, dma->size);

	release_dma_lock(flags);

	release_dma_lock(flags);

}

}

EXPORT_SYMBOL_GPL(labpc_drain_dma);

EXPORT_SYMBOL_GPL(labpc_drain_dma);