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staging: comedi: pcl812: use common function to setup dma

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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: 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 10:05:16 -07:00
committed by Greg Kroah-Hartman
parent 92afc2b229
commit a7f0ce8e5d
1 changed files with 19 additions and 33 deletions
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52
drivers/staging/comedi/drivers/pcl812.c
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@@ -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 comedi_subdevice *s,
unsigned int unread_samples)
{
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);
}