staging: comedi: ni_labpc: migrate labpc_drain_dma()

Move `labpc_drain_dma()` into the "ni_labpc_isadma" module.  Provide a
dummy inline function in "ni_labpc_isadma.h" if the module is not being
built.
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

@@ -906,60 +906,6 @@ static int labpc_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
 }
 
 #ifdef CONFIG_ISA_DMA_API
-static void labpc_drain_dma(struct comedi_device *dev)
-{
-	struct labpc_private *devpriv = dev->private;
-	struct comedi_subdevice *s = dev->read_subdev;
-	struct comedi_async *async = s->async;
-	int status;
-	unsigned long flags;
-	unsigned int max_points, num_points, residue, leftover;
-	int i;
-
-	status = devpriv->stat1;
-
-	flags = claim_dma_lock();
-	disable_dma(devpriv->dma_chan);
-	/* clear flip-flop to make sure 2-byte registers for
-	 * count and address get set correctly */
-	clear_dma_ff(devpriv->dma_chan);
-
-	/*  figure out how many points to read */
-	max_points = devpriv->dma_transfer_size / sample_size;
-	/* residue is the number of points 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 = get_dma_residue(devpriv->dma_chan) / sample_size;
-	num_points = max_points - residue;
-	if (devpriv->count < num_points && async->cmd.stop_src == TRIG_COUNT)
-		num_points = devpriv->count;
-
-	/*  figure out how many points will be stored next time */
-	leftover = 0;
-	if (async->cmd.stop_src != TRIG_COUNT) {
-		leftover = devpriv->dma_transfer_size / sample_size;
-	} else if (devpriv->count > num_points) {
-		leftover = devpriv->count - num_points;
-		if (leftover > max_points)
-			leftover = max_points;
-	}
-
-	/* write data to comedi buffer */
-	for (i = 0; i < num_points; i++)
-		cfc_write_to_buffer(s, devpriv->dma_buffer[i]);
-
-	if (async->cmd.stop_src == TRIG_COUNT)
-		devpriv->count -= num_points;
-
-	/*  set address and count for next transfer */
-	set_dma_addr(devpriv->dma_chan, devpriv->dma_addr);
-	set_dma_count(devpriv->dma_chan, leftover * sample_size);
-	release_dma_lock(flags);
-
-	async->events |= COMEDI_CB_BLOCK;
-}
-
 static void handle_isa_dma(struct comedi_device *dev)
 {
 	struct labpc_private *devpriv = dev->private;
@@ -1009,12 +955,10 @@ static int labpc_drain_fifo(struct comedi_device *dev)
  * when acquisition is terminated by stop_src == TRIG_EXT). */
 static void labpc_drain_dregs(struct comedi_device *dev)
 {
-#ifdef CONFIG_ISA_DMA_API
 	struct labpc_private *devpriv = dev->private;
 
 	if (devpriv->current_transfer == isa_dma_transfer)
 		labpc_drain_dma(dev);
-#endif
 
 	labpc_drain_fifo(dev);
 }

drivers/staging/comedi/drivers/ni_labpc_isadma.c

@@ -23,6 +23,7 @@
 
 #include <asm/dma.h>
 
+#include "comedi_fc.h"
 #include "ni_labpc.h"
 #include "ni_labpc_regs.h"
 #include "ni_labpc_isadma.h"
@@ -81,6 +82,61 @@ void labpc_setup_dma(struct comedi_device *dev, struct comedi_subdevice *s)
 }
 EXPORT_SYMBOL_GPL(labpc_setup_dma);
 
+void labpc_drain_dma(struct comedi_device *dev)
+{
+	struct labpc_private *devpriv = dev->private;
+	struct comedi_subdevice *s = dev->read_subdev;
+	struct comedi_async *async = s->async;
+	int status;
+	unsigned long flags;
+	unsigned int max_points, num_points, residue, leftover;
+	int i;
+
+	status = devpriv->stat1;
+
+	flags = claim_dma_lock();
+	disable_dma(devpriv->dma_chan);
+	/* clear flip-flop to make sure 2-byte registers for
+	 * count and address get set correctly */
+	clear_dma_ff(devpriv->dma_chan);
+
+	/* figure out how many points to read */
+	max_points = devpriv->dma_transfer_size / sample_size;
+	/* residue is the number of points 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 = get_dma_residue(devpriv->dma_chan) / sample_size;
+	num_points = max_points - residue;
+	if (devpriv->count < num_points && async->cmd.stop_src == TRIG_COUNT)
+		num_points = devpriv->count;
+
+	/* figure out how many points will be stored next time */
+	leftover = 0;
+	if (async->cmd.stop_src != TRIG_COUNT) {
+		leftover = devpriv->dma_transfer_size / sample_size;
+	} else if (devpriv->count > num_points) {
+		leftover = devpriv->count - num_points;
+		if (leftover > max_points)
+			leftover = max_points;
+	}
+
+	/* write data to comedi buffer */
+	for (i = 0; i < num_points; i++)
+		cfc_write_to_buffer(s, devpriv->dma_buffer[i]);
+
+	if (async->cmd.stop_src == TRIG_COUNT)
+		devpriv->count -= num_points;
+
+	/* set address and count for next transfer */
+	set_dma_addr(devpriv->dma_chan, devpriv->dma_addr);
+	set_dma_count(devpriv->dma_chan, leftover * sample_size);
+	release_dma_lock(flags);
+
+	async->events |= COMEDI_CB_BLOCK;
+}
+EXPORT_SYMBOL_GPL(labpc_drain_dma);
+
 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

@@ -19,6 +19,7 @@ static inline bool labpc_have_dma_chan(struct comedi_device *dev)
 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);
 
 #else
 
@@ -42,6 +43,10 @@ static inline void labpc_setup_dma(struct comedi_device *dev,
 {
 }
 
+static inline void labpc_drain_dma(struct comedi_device *dev)
+{
+}
+
 #endif
 
 #endif /* _NI_LABPC_ISADMA_H */