staging: comedi: pcl818: factor out dma setup to helper functions

To assist in cleaning up the the rest of the driver, factor the initial
dma setup and the next dma buffer setup into helper functions.
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>

drivers/staging/comedi/drivers/pcl818.c

@@ -362,6 +362,61 @@ 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 pcl818_private *devpriv = dev->private;
+	struct comedi_cmd *cmd = &s->async->cmd;
+	unsigned int flags;
+	unsigned int bytes;
+
+	disable_dma(devpriv->dma);	/*  disable dma */
+	bytes = devpriv->hwdmasize;
+	if (cmd->stop_src == TRIG_COUNT) {
+		bytes = cmd->chanlist_len * cmd->stop_arg * sizeof(short);
+		devpriv->dma_runs_to_end = bytes / devpriv->hwdmasize;
+		devpriv->last_dma_run = bytes % devpriv->hwdmasize;
+		devpriv->dma_runs_to_end--;
+		if (devpriv->dma_runs_to_end >= 0)
+			bytes = devpriv->hwdmasize;
+	}
+
+	devpriv->next_dma_buf = 0;
+	set_dma_mode(devpriv->dma, DMA_MODE_READ);
+	flags = claim_dma_lock();
+	clear_dma_ff(devpriv->dma);
+	set_dma_addr(devpriv->dma, devpriv->hwdmaptr[0]);
+	set_dma_count(devpriv->dma, bytes);
+	release_dma_lock(flags);
+	enable_dma(devpriv->dma);
+}
+
+static void pcl818_ai_setup_next_dma(struct comedi_device *dev,
+				     struct comedi_subdevice *s)
+{
+	struct pcl818_private *devpriv = dev->private;
+	struct comedi_cmd *cmd = &s->async->cmd;
+	unsigned long flags;
+
+	disable_dma(devpriv->dma);
+	devpriv->next_dma_buf = 1 - devpriv->next_dma_buf;
+	if (devpriv->dma_runs_to_end > -1 || cmd->stop_src == TRIG_NONE) {
+		/* switch dma bufs */
+		set_dma_mode(devpriv->dma, DMA_MODE_READ);
+		flags = claim_dma_lock();
+		set_dma_addr(devpriv->dma,
+			     devpriv->hwdmaptr[devpriv->next_dma_buf]);
+		if (devpriv->dma_runs_to_end || cmd->stop_src == TRIG_NONE)
+			set_dma_count(devpriv->dma, devpriv->hwdmasize);
+		else
+			set_dma_count(devpriv->dma, devpriv->last_dma_run);
+		release_dma_lock(flags);
+		enable_dma(devpriv->dma);
+	}
+
+	devpriv->dma_runs_to_end--;
+}
+
 static unsigned int pcl818_ai_get_sample(struct comedi_device *dev,
 					 struct comedi_subdevice *s,
 					 unsigned int *chan)
@@ -546,26 +601,10 @@ static irqreturn_t interrupt_pcl818_ai_mode13_dma(int irq, void *d)
 	struct comedi_subdevice *s = dev->read_subdev;
 	struct comedi_cmd *cmd = &s->async->cmd;
 	int i, len, bufptr;
-	unsigned long flags;
 	unsigned short *ptr;
 
-	disable_dma(devpriv->dma);
-	devpriv->next_dma_buf = 1 - devpriv->next_dma_buf;
-	if (devpriv->dma_runs_to_end > -1 || cmd->stop_src == TRIG_NONE) {
-		/* switch dma bufs */
-		set_dma_mode(devpriv->dma, DMA_MODE_READ);
-		flags = claim_dma_lock();
-		set_dma_addr(devpriv->dma,
-			     devpriv->hwdmaptr[devpriv->next_dma_buf]);
-		if (devpriv->dma_runs_to_end || cmd->stop_src == TRIG_NONE)
-			set_dma_count(devpriv->dma, devpriv->hwdmasize);
-		else
-			set_dma_count(devpriv->dma, devpriv->last_dma_run);
-		release_dma_lock(flags);
-		enable_dma(devpriv->dma);
-	}
+	pcl818_ai_setup_next_dma(dev, s);
 
-	devpriv->dma_runs_to_end--;
 	outb(0, dev->iobase + PCL818_CLRINT);	/* clear INT request */
 	ptr = (unsigned short *)devpriv->dmabuf[1 - devpriv->next_dma_buf];
 
@@ -744,29 +783,8 @@ static void pcl818_ai_mode13dma_int(int mode, struct comedi_device *dev,
 				    struct comedi_subdevice *s)
 {
 	struct pcl818_private *devpriv = dev->private;
-	struct comedi_cmd *cmd = &s->async->cmd;
-	unsigned int flags;
-	unsigned int bytes;
-
-	disable_dma(devpriv->dma);	/*  disable dma */
-	bytes = devpriv->hwdmasize;
-	if (cmd->stop_src == TRIG_COUNT) {
-		bytes = cmd->chanlist_len * cmd->stop_arg * sizeof(short);
-		devpriv->dma_runs_to_end = bytes / devpriv->hwdmasize;
-		devpriv->last_dma_run = bytes % devpriv->hwdmasize;
-		devpriv->dma_runs_to_end--;
-		if (devpriv->dma_runs_to_end >= 0)
-			bytes = devpriv->hwdmasize;
-	}
 
-	devpriv->next_dma_buf = 0;
-	set_dma_mode(devpriv->dma, DMA_MODE_READ);
-	flags = claim_dma_lock();
-	clear_dma_ff(devpriv->dma);
-	set_dma_addr(devpriv->dma, devpriv->hwdmaptr[0]);
-	set_dma_count(devpriv->dma, bytes);
-	release_dma_lock(flags);
-	enable_dma(devpriv->dma);
+	pcl818_ai_setup_dma(dev, s);
 
 	if (mode == 1) {
 		devpriv->ai_mode = INT_TYPE_AI1_DMA;