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: H Hartley Sweeten <hsweeten@xxxxxxxxxxxxxxxxxxx>
Cc: Ian Abbott <abbotti@xxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/staging/comedi/drivers/ni_labpc_isadma.c | 48 ++++++++++++------------
1 file changed, 24 insertions(+), 24 deletions(-)
diff --git a/drivers/staging/comedi/drivers/ni_labpc_isadma.c b/drivers/staging/comedi/drivers/ni_labpc_isadma.c
index 862fb7e..2fb7e72 100644
--- a/drivers/staging/comedi/drivers/ni_labpc_isadma.c
+++ b/drivers/staging/comedi/drivers/ni_labpc_isadma.c
@@ -105,12 +105,11 @@ void labpc_drain_dma(struct comedi_device *dev)
struct comedi_subdevice *s = dev->read_subdev;
struct comedi_async *async = s->async;
struct comedi_cmd *cmd = &async->cmd;
- unsigned int sample_size = comedi_bytes_per_sample(s);
- int status;
+ unsigned int max_samples = comedi_bytes_to_samples(s, dma->size);
+ unsigned int residue;
+ unsigned int nsamples;
+ unsigned int leftover;
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
@@ -119,32 +118,33 @@ void labpc_drain_dma(struct comedi_device *dev)
*/
residue = labpc_isadma_disable(dma);
- /* figure out how many points to read */
- max_points = dma->size / sample_size;
- num_points = max_points - comedi_bytes_to_samples(s, residue);
- if (cmd->stop_src == TRIG_COUNT && devpriv->count < num_points)
- num_points = devpriv->count;
-
- /* figure out how many points will be stored next time */
- leftover = 0;
- if (cmd->stop_src != TRIG_COUNT) {
- leftover = dma->size / sample_size;
- } else if (devpriv->count > num_points) {
- leftover = devpriv->count - num_points;
- if (leftover > max_points)
- leftover = max_points;
+ /*
+ * Figure out how many samples to read for this transfer and
+ * how many will be stored for next time.
+ */
+ nsamples = max_samples - comedi_bytes_to_samples(s, residue);
+ if (cmd->stop_src == TRIG_COUNT) {
+ if (devpriv->count <= nsamples) {
+ nsamples = devpriv->count;
+ leftover = 0;
+ } else {
+ leftover = devpriv->count - nsamples;
+ if (leftover > max_samples)
+ leftover = max_samples;
+ }
+ 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);
-
- if (cmd->stop_src == TRIG_COUNT)
- devpriv->count -= num_points;
+ comedi_buf_write_samples(s, dma->virt_addr, nsamples);
/* set address and count for next transfer */
flags = claim_dma_lock();
set_dma_mode(dma->chan, DMA_MODE_READ);
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);
}
EXPORT_SYMBOL_GPL(labpc_drain_dma);
--
2.0.3
_______________________________________________
devel mailing list
devel@xxxxxxxxxxxxxxxxxxxxxx
http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
