Commit a7f0ce8e authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
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staging: comedi: pcl812: use common function to setup dma 



The pcl812_ai_setup_dma() and pcl812_ai_setup_next_dma() functions are similar
other than the buffer switch and the inclusion of the "unread_samples" in
pcl818_ai_setup_next_dma() when calculating the dma size.

Merge these two functions by initializing the 'dma->cur_dma' in the callers
and passing '0' for the "unread_samples" when first starting the 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 92afc2b2

drivers/staging/comedi/drivers/pcl812.c

+19 −33
Original line number Diff line number Diff line
@@ -538,47 +538,27 @@ static void pcl812_start_pacer(struct comedi_device *dev, bool load_timers) 
}



static void pcl812_ai_setup_dma(struct comedi_device *dev,

				struct comedi_subdevice *s)

{

	struct pcl812_private *devpriv = dev->private;

	struct comedi_isadma *dma = devpriv->dma;

	struct comedi_isadma_desc *desc = &dma->desc[0];

	unsigned int bytes;

	unsigned int nsamples;



	dma->cur_dma = 0;



	/* if using EOS, adapt DMA buffer to one scan */

	bytes = devpriv->ai_eos ? comedi_bytes_per_scan(s) : desc->maxsize;



	nsamples = comedi_bytes_to_samples(s, bytes);

	nsamples = comedi_nsamples_left(s, nsamples);

	desc->size = comedi_samples_to_bytes(s, nsamples);

	comedi_isadma_program(desc);

}



static void pcl812_ai_setup_next_dma(struct comedi_device *dev,

				struct comedi_subdevice *s,

				unsigned int unread_samples)

{

	struct pcl812_private *devpriv = dev->private;

	struct comedi_isadma *dma = devpriv->dma;

	struct comedi_isadma_desc *desc;

	struct comedi_isadma_desc *desc = &dma->desc[dma->cur_dma];

	unsigned int bytes;

	unsigned int max_samples;

	unsigned int nsamples;



	comedi_isadma_disable(dma->chan);



	dma->cur_dma = 1 - dma->cur_dma;

	desc = &dma->desc[dma->cur_dma];



	/* if using EOS, adapt DMA buffer to one scan */

	bytes = devpriv->ai_eos ? comedi_bytes_per_scan(s) : desc->maxsize;



	max_samples = comedi_bytes_to_samples(s, bytes);

	nsamples = max_samples + unread_samples;

	nsamples = comedi_nsamples_left(s, nsamples);



	/*

	 * Determine dma size based on the buffer size plus the number of

	 * unread samples and the number of samples remaining in the command.

	 */

	nsamples = comedi_nsamples_left(s, max_samples + unread_samples);

	if (nsamples > max_samples) {

		nsamples -= max_samples;

		desc->size = comedi_samples_to_bytes(s, nsamples);
@@ -740,6 +720,7 @@ static int pcl812_ai_cmdtest(struct comedi_device *dev, 
static int pcl812_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)

{

	struct pcl812_private *devpriv = dev->private;

	struct comedi_isadma *dma = devpriv->dma;

	struct comedi_cmd *cmd = &s->async->cmd;

	unsigned int ctrl = 0;

	unsigned int i;
@@ -748,7 +729,7 @@ static int pcl812_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s) 


	pcl812_ai_set_chan_range(dev, cmd->chanlist[0], 1);



	if (devpriv->dma) {	/*  check if we can use DMA transfer */

	if (dma) {	/*  check if we can use DMA transfer */

		devpriv->ai_dma = 1;

		for (i = 1; i < cmd->chanlist_len; i++)

			if (cmd->chanlist[0] != cmd->chanlist[i]) {
@@ -771,8 +752,11 @@ static int pcl812_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s) 
			devpriv->ai_dma = 0;

	}



	if (devpriv->ai_dma)

		pcl812_ai_setup_dma(dev, s);

	if (devpriv->ai_dma) {

		/* setup and enable dma for the first buffer */

		dma->cur_dma = 0;

		pcl812_ai_setup_dma(dev, s, 0);

	}



	switch (cmd->convert_src) {

	case TRIG_TIMER:
@@ -859,7 +843,9 @@ static void pcl812_handle_dma(struct comedi_device *dev, 
	bufptr = devpriv->ai_poll_ptr;

	devpriv->ai_poll_ptr = 0;



	pcl812_ai_setup_next_dma(dev, s, nsamples);

	/* restart dma with the next buffer */

	dma->cur_dma = 1 - dma->cur_dma;

	pcl812_ai_setup_dma(dev, s, nsamples);



	transfer_from_dma_buf(dev, s, desc->virt_addr, bufptr, nsamples);

}

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