staging: comedi: ni_labpc: migrate DMA status handling

Migrate the code for checking and handling the interrupt status handling
for ISA DMA transfers into new a new function
`labpc_handle_dma_status()` in the "ni_labpc_isadma" module.  Provide a
dummy inline function in "ni_labpc_isadma.h" if the "ni_labpc_isadma"
module is not being built.

The static function `handle_isa_dma()` also needs to move across to the
new module.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/ni_labpc.c

@@ -905,20 +905,6 @@ static int labpc_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
 	return 0;
 }
 
-#ifdef CONFIG_ISA_DMA_API
-static void handle_isa_dma(struct comedi_device *dev)
-{
-	struct labpc_private *devpriv = dev->private;
-
-	labpc_drain_dma(dev);
-
-	enable_dma(devpriv->dma_chan);
-
-	/*  clear dma tc interrupt */
-	devpriv->write_byte(0x1, dev->iobase + DMATC_CLEAR_REG);
-}
-#endif
-
 /* read all available samples from ai fifo */
 static int labpc_drain_fifo(struct comedi_device *dev)
 {
@@ -1003,18 +989,9 @@ static irqreturn_t labpc_interrupt(int irq, void *d)
 		return IRQ_HANDLED;
 	}
 
-#ifdef CONFIG_ISA_DMA_API
-	if (devpriv->current_transfer == isa_dma_transfer) {
-		/*
-		 * if a dma terminal count of external stop trigger
-		 * has occurred
-		 */
-		if (devpriv->stat1 & STAT1_GATA0 ||
-		    (board->is_labpc1200 && devpriv->stat2 & STAT2_OUTA1)) {
-			handle_isa_dma(dev);
-		}
-	} else
-#endif
+	if (devpriv->current_transfer == isa_dma_transfer)
+		labpc_handle_dma_status(dev);
+	else
 		labpc_drain_fifo(dev);
 
 	if (devpriv->stat1 & STAT1_CNTINT) {

drivers/staging/comedi/drivers/ni_labpc_isadma.c

@@ -137,6 +137,33 @@ void labpc_drain_dma(struct comedi_device *dev)
 }
 EXPORT_SYMBOL_GPL(labpc_drain_dma);
 
+static void handle_isa_dma(struct comedi_device *dev)
+{
+	struct labpc_private *devpriv = dev->private;
+
+	labpc_drain_dma(dev);
+
+	enable_dma(devpriv->dma_chan);
+
+	/* clear dma tc interrupt */
+	devpriv->write_byte(0x1, dev->iobase + DMATC_CLEAR_REG);
+}
+
+void labpc_handle_dma_status(struct comedi_device *dev)
+{
+	const struct labpc_boardinfo *board = comedi_board(dev);
+	struct labpc_private *devpriv = dev->private;
+
+	/*
+	 * if a dma terminal count of external stop trigger
+	 * has occurred
+	 */
+	if (devpriv->stat1 & STAT1_GATA0 ||
+	    (board->is_labpc1200 && devpriv->stat2 & STAT2_OUTA1))
+		handle_isa_dma(dev);
+}
+EXPORT_SYMBOL_GPL(labpc_handle_dma_status);
+
 int labpc_init_dma_chan(struct comedi_device *dev, unsigned int dma_chan)
 {
 	struct labpc_private *devpriv = dev->private;

drivers/staging/comedi/drivers/ni_labpc_isadma.h

@@ -20,6 +20,7 @@ int labpc_init_dma_chan(struct comedi_device *dev, unsigned int dma_chan);
 void labpc_free_dma_chan(struct comedi_device *dev);
 void labpc_setup_dma(struct comedi_device *dev, struct comedi_subdevice *s);
 void labpc_drain_dma(struct comedi_device *dev);
+void labpc_handle_dma_status(struct comedi_device *dev);
 
 #else
 
@@ -47,6 +48,10 @@ static inline void labpc_drain_dma(struct comedi_device *dev)
 {
 }
 
+static inline void labpc_handle_dma_status(struct comedi_device *dev)
+{
+}
+
 #endif
 
 #endif /* _NI_LABPC_ISADMA_H */