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staging: comedi: pcl816: use common function to setup dma

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THe pcl816_ai_setup_dma() and pcl816_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: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
H Hartley Sweeten 2015-01-14 10:05:14 -07:00 committed by Greg Kroah-Hartman
parent fe4a22a009
commit 93e6045236
1 changed files with 11 additions and 32 deletions
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43
drivers/staging/comedi/drivers/pcl816.c
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@ -142,47 +142,22 @@ static void pcl816_start_pacer(struct comedi_device *dev, bool load_counters)
}
static void pcl816_ai_setup_dma(struct comedi_device *dev,
struct comedi_subdevice *s)
struct comedi_subdevice *s,
unsigned int unread_samples)
{
struct pcl816_private *devpriv = dev->private;
struct comedi_isadma *dma = devpriv->dma;
struct comedi_isadma_desc *desc = &dma->desc[0];
unsigned int nsamples;
dma->cur_dma = 0;
/*
* Determine dma size based on the buffer maxsize and the number of
* samples remaining in the command.
*/
nsamples = comedi_bytes_to_samples(s, desc->maxsize);
nsamples = comedi_nsamples_left(s, nsamples);
desc->size = comedi_samples_to_bytes(s, nsamples);
comedi_isadma_program(desc);
}
static void pcl816_ai_setup_next_dma(struct comedi_device *dev,
struct comedi_subdevice *s,
unsigned int unread_samples)
{
struct pcl816_private *devpriv = dev->private;
struct comedi_isadma *dma = devpriv->dma;
struct comedi_isadma_desc *desc;
unsigned int max_samples;
struct comedi_isadma_desc *desc = &dma->desc[dma->cur_dma];
unsigned int max_samples = comedi_bytes_to_samples(s, desc->maxsize);
unsigned int nsamples;
comedi_isadma_disable(dma->chan);
dma->cur_dma = 1 - dma->cur_dma;
desc = &dma->desc[dma->cur_dma];
/*
* Determine dma size based on the buffer maxsize plus the number of
* unread samples and the number of samples remaining in the command.
*/
max_samples = comedi_bytes_to_samples(s, desc->maxsize);
nsamples = max_samples + unread_samples;
nsamples = comedi_nsamples_left(s, nsamples);
nsamples = comedi_nsamples_left(s, max_samples + unread_samples);
if (nsamples > unread_samples) {
nsamples -= unread_samples;
desc->size = comedi_samples_to_bytes(s, nsamples);
@ -321,7 +296,9 @@ static irqreturn_t pcl816_interrupt(int irq, void *d)
bufptr = devpriv->ai_poll_ptr;
devpriv->ai_poll_ptr = 0;
pcl816_ai_setup_next_dma(dev, s, nsamples);
/* restart dma with the next buffer */
dma->cur_dma = 1 - dma->cur_dma;
pcl816_ai_setup_dma(dev, s, nsamples);
transfer_from_dma_buf(dev, s, desc->virt_addr, bufptr, nsamples);
@ -485,7 +462,9 @@ static int pcl816_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
devpriv->ai_poll_ptr = 0;
devpriv->ai_cmd_canceled = 0;
pcl816_ai_setup_dma(dev, s);
/* setup and enable dma for the first buffer */
dma->cur_dma = 0;
pcl816_ai_setup_dma(dev, s, 0);
pcl816_start_pacer(dev, true);