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staging: comedi: pcl818: use common function to setup dma

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THe pcl818_ai_setup_dma() and pcl818_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 10:05:12 -07:00
committed by Greg Kroah-Hartman
parent 296e3f1816
commit 421f1b6832
1 changed files with 13 additions and 35 deletions
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48
drivers/staging/comedi/drivers/pcl818.c
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@@ -332,49 +332,22 @@ static void pcl818_start_pacer(struct comedi_device *dev, bool load_counters)
}
static void pcl818_ai_setup_dma(struct comedi_device *dev,
struct comedi_subdevice *s)
struct comedi_subdevice *s,
unsigned int unread_samples)
{
struct pcl818_private *devpriv = dev->private;
struct comedi_isadma *dma = devpriv->dma;
struct comedi_isadma_desc *desc = &dma->desc[0];
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 = 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 pcl818_ai_setup_next_dma(struct comedi_device *dev,
struct comedi_subdevice *s,
unsigned int unread_samples)
{
struct pcl818_private *devpriv = dev->private;
struct comedi_isadma *dma = devpriv->dma;
struct comedi_isadma_desc *desc;
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];
/*
* 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);
@@ -554,7 +527,9 @@ static void pcl818_handle_dma(struct comedi_device *dev,
unsigned int val;
int i;
pcl818_ai_setup_next_dma(dev, s, nsamples);
/* restart dma with the next buffer */
dma->cur_dma = 1 - dma->cur_dma;
pcl818_ai_setup_dma(dev, s, nsamples);
for (i = 0; i < nsamples; i++) {
val = ptr[i];
@@ -790,6 +765,7 @@ static int pcl818_ai_cmd(struct comedi_device *dev,
struct comedi_subdevice *s)
{
struct pcl818_private *devpriv = dev->private;
struct comedi_isadma *dma = devpriv->dma;
struct comedi_cmd *cmd = &s->async->cmd;
unsigned int ctrl = 0;
unsigned int seglen;
@@ -815,8 +791,10 @@ static int pcl818_ai_cmd(struct comedi_device *dev,
outb(PCL818_CNTENABLE_PACER_ENA, dev->iobase + PCL818_CNTENABLE_REG);
if (devpriv->dma) {
pcl818_ai_setup_dma(dev, s);
if (dma) {
/* setup and enable dma for the first buffer */
dma->cur_dma = 0;
pcl818_ai_setup_dma(dev, s, 0);
ctrl |= PCL818_CTRL_INTE | PCL818_CTRL_IRQ(dev->irq) |
PCL818_CTRL_DMAE;