Introduce a helper function to disable and the ISA DMA controller and
return the residue as described in Documentation/DMA-ISA-LPC.txt.
Signed-off-by: H Hartley Sweeten <hsweeten@xxxxxxxxxxxxxxxxxxx>
Cc: Ian Abbott <abbotti@xxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/staging/comedi/drivers/ni_at_a2150.c | 42 +++++++++++++++-------------
1 file changed, 23 insertions(+), 19 deletions(-)
diff --git a/drivers/staging/comedi/drivers/ni_at_a2150.c b/drivers/staging/comedi/drivers/ni_at_a2150.c
index 23c59cb..73768d0 100644
--- a/drivers/staging/comedi/drivers/ni_at_a2150.c
+++ b/drivers/staging/comedi/drivers/ni_at_a2150.c
@@ -172,12 +172,24 @@ static void a2150_isadma_program(struct a2150_dma_desc *dma)
release_dma_lock(flags);
}
+static unsigned int a2150_isadma_disable(struct a2150_dma_desc *dma)
+{
+ unsigned long flags;
+ unsigned int residue;
+
+ flags = claim_dma_lock();
+ disable_dma(dma->chan);
+ residue = get_dma_residue(dma->chan);
+ release_dma_lock(flags);
+
+ return residue;
+}
+
/* interrupt service routine */
static irqreturn_t a2150_interrupt(int irq, void *d)
{
int i;
int status;
- unsigned long flags;
struct comedi_device *dev = d;
struct a2150_private *devpriv = dev->private;
struct a2150_dma_desc *dma = &devpriv->dma_desc;
@@ -217,21 +229,16 @@ static irqreturn_t a2150_interrupt(int irq, void *d)
return IRQ_HANDLED;
}
- flags = claim_dma_lock();
- disable_dma(dma->chan);
- /* clear flip-flop to make sure 2-byte registers for
- * count and address get set correctly */
- clear_dma_ff(dma->chan);
-
- /* figure out how many points to read */
- max_points = comedi_bytes_to_samples(s, dma->size);
- /* residue is the number of points left to be done on the dma
+ /*
+ * residue is the number of bytes left to be done on the dma
* transfer. It should always be zero at this point unless
* the stop_src is set to external triggering.
*/
- residue = comedi_bytes_to_samples(s, get_dma_residue(dma->chan));
- release_dma_lock(flags);
- num_points = max_points - residue;
+ residue = a2150_isadma_disable(dma);
+
+ /* figure out how many points to read */
+ max_points = comedi_bytes_to_samples(s, dma->size);
+ num_points = max_points - comedi_bytes_to_samples(s, residue);
if (devpriv->count < num_points && cmd->stop_src == TRIG_COUNT)
num_points = devpriv->count;
@@ -288,7 +295,7 @@ static int a2150_cancel(struct comedi_device *dev, struct comedi_subdevice *s)
outw(devpriv->irq_dma_bits, dev->iobase + IRQ_DMA_CNTRL_REG);
/* disable computer's dma */
- disable_dma(dma->chan);
+ a2150_isadma_disable(dma);
/* clear fifo and reset triggering circuitry */
outw(0, dev->iobase + FIFO_RESET_REG);
@@ -524,7 +531,6 @@ static int a2150_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
struct comedi_async *async = s->async;
struct comedi_cmd *cmd = &async->cmd;
unsigned long timer_base = dev->iobase + I8253_BASE_REG;
- unsigned long lock_flags;
unsigned int old_config_bits = devpriv->config_bits;
unsigned int trigger_bits;
@@ -560,9 +566,7 @@ static int a2150_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
/* initialize number of samples remaining */
devpriv->count = cmd->stop_arg * cmd->chanlist_len;
- lock_flags = claim_dma_lock();
- disable_dma(dma->chan);
- release_dma_lock(lock_flags);
+ a2150_isadma_disable(dma);
/* set size of transfer to fill in 1/3 second */
#define ONE_THIRD_SECOND 333333333
@@ -730,7 +734,7 @@ static void a2150_alloc_irq_dma(struct comedi_device *dev,
dma->chan = dma_chan;
devpriv->irq_dma_bits = IRQ_LVL_BITS(irq_num) | DMA_CHAN_BITS(dma_chan);
- disable_dma(dma_chan);
+ a2150_isadma_disable(dma);
}
static void a2150_free_dma(struct comedi_device *dev)
--
2.0.3
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