staging: comedi: mite: introduce mite_sync_dma()

The struct mite_channel 'dir' member specifies if the dma is input
or output. Wrap the mite_sync_input_dma() and mite_sync_output_dma()
functions with a single mite_sync_dma() so that the drivers don't
have to worry about the sync direction.

The functions that actually sync the input/output dma currently return
-1 if an overflow/underrun is detected otherwise they return 0. If an
overflow/underrun is detected the async->event COMEDI_CB_OVERFLOW is
also set.

The callers never check the return value anyway so just make the
functions return void. The async->event can be checked if necessary
to detect any errors.
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/mite.c

@@ -680,8 +680,8 @@ void mite_dma_disarm(struct mite_channel *mite_chan)
 }
 EXPORT_SYMBOL_GPL(mite_dma_disarm);
 
-int mite_sync_input_dma(struct mite_channel *mite_chan,
-			struct comedi_subdevice *s)
+static void mite_sync_input_dma(struct mite_channel *mite_chan,
+				struct comedi_subdevice *s)
 {
 	struct comedi_async *async = s->async;
 	int count;
@@ -697,7 +697,7 @@ int mite_sync_input_dma(struct mite_channel *mite_chan,
 		dev_warn(s->device->class_dev,
 			 "mite: DMA overwrite of free area\n");
 		async->events |= COMEDI_CB_OVERFLOW;
-		return -1;
+		return;
 	}
 
 	count = nbytes - async->buf_write_count;
@@ -705,18 +705,15 @@ int mite_sync_input_dma(struct mite_channel *mite_chan,
 	 * it's possible count will be negative due to conservative value
 	 * returned by mite_bytes_written_to_memory_lb
 	 */
-	if (count <= 0)
-		return 0;
-
-	comedi_buf_write_free(s, count);
-	comedi_inc_scan_progress(s, count);
-	async->events |= COMEDI_CB_BLOCK;
-	return 0;
+	if (count > 0) {
+		comedi_buf_write_free(s, count);
+		comedi_inc_scan_progress(s, count);
+		async->events |= COMEDI_CB_BLOCK;
+	}
 }
-EXPORT_SYMBOL_GPL(mite_sync_input_dma);
 
-int mite_sync_output_dma(struct mite_channel *mite_chan,
-			 struct comedi_subdevice *s)
+static void mite_sync_output_dma(struct mite_channel *mite_chan,
+				 struct comedi_subdevice *s)
 {
 	struct comedi_async *async = s->async;
 	struct comedi_cmd *cmd = &async->cmd;
@@ -739,7 +736,7 @@ int mite_sync_output_dma(struct mite_channel *mite_chan,
 	    ((int)(nbytes_ub - old_alloc_count) > 0)) {
 		dev_warn(s->device->class_dev, "mite: DMA underrun\n");
 		async->events |= COMEDI_CB_OVERFLOW;
-		return -1;
+		return;
 	}
 
 	if (finite_regen) {
@@ -749,20 +746,24 @@ int mite_sync_output_dma(struct mite_channel *mite_chan,
 		 * hence we expect that old_alloc_count will reach a maximum of
 		 * stop_count bytes.
 		 */
-		return 0;
+		return;
 	}
 
 	count = nbytes_lb - async->buf_read_count;
-	if (count <= 0)
-		return 0;
-
-	if (count) {
+	if (count > 0) {
 		comedi_buf_read_free(s, count);
 		async->events |= COMEDI_CB_BLOCK;
 	}
-	return 0;
 }
-EXPORT_SYMBOL_GPL(mite_sync_output_dma);
+
+void mite_sync_dma(struct mite_channel *mite_chan, struct comedi_subdevice *s)
+{
+	if (mite_chan->dir == COMEDI_INPUT)
+		mite_sync_input_dma(mite_chan, s);
+	else
+		mite_sync_output_dma(mite_chan, s);
+}
+EXPORT_SYMBOL_GPL(mite_sync_dma);
 
 static unsigned int mite_get_status(struct mite_channel *mite_chan)
 {

drivers/staging/comedi/drivers/mite.h

@@ -90,10 +90,7 @@ void mite_release_channel(struct mite_channel *mite_chan);
 
 void mite_dma_arm(struct mite_channel *mite_chan);
 void mite_dma_disarm(struct mite_channel *mite_chan);
-int mite_sync_input_dma(struct mite_channel *mite_chan,
-			struct comedi_subdevice *s);
-int mite_sync_output_dma(struct mite_channel *mite_chan,
-			 struct comedi_subdevice *s);
+void mite_sync_dma(struct mite_channel *mite_chan, struct comedi_subdevice *s);
 u32 mite_bytes_in_transit(struct mite_channel *mite_chan);
 unsigned int mite_ack_linkc(struct mite_channel *mite_chan);
 int mite_done(struct mite_channel *mite_chan);

drivers/staging/comedi/drivers/ni_660x.c

@@ -460,7 +460,7 @@ static int ni_660x_input_poll(struct comedi_device *dev,
 
 	/* lock to avoid race with comedi_poll */
 	spin_lock_irqsave(&devpriv->interrupt_lock, flags);
-	mite_sync_input_dma(counter->mite_chan, s);
+	mite_sync_dma(counter->mite_chan, s);
 	spin_unlock_irqrestore(&devpriv->interrupt_lock, flags);
 	return comedi_buf_read_n_available(s);
 }

drivers/staging/comedi/drivers/ni_mio_common.c

@@ -890,7 +890,7 @@ static void ni_sync_ai_dma(struct comedi_device *dev)
 
 	spin_lock_irqsave(&devpriv->mite_channel_lock, flags);
 	if (devpriv->ai_mite_chan)
-		mite_sync_input_dma(devpriv->ai_mite_chan, s);
+		mite_sync_dma(devpriv->ai_mite_chan, s);
 	spin_unlock_irqrestore(&devpriv->mite_channel_lock, flags);
 }
 
@@ -936,7 +936,7 @@ static void mite_handle_b_linkc(struct mite_struct *mite,
 
 	spin_lock_irqsave(&devpriv->mite_channel_lock, flags);
 	if (devpriv->ao_mite_chan)
-		mite_sync_output_dma(devpriv->ao_mite_chan, s);
+		mite_sync_dma(devpriv->ao_mite_chan, s);
 	spin_unlock_irqrestore(&devpriv->mite_channel_lock, flags);
 }
 
@@ -3698,7 +3698,7 @@ static void handle_cdio_interrupt(struct comedi_device *dev)
 	spin_lock_irqsave(&devpriv->mite_channel_lock, flags);
 	if (devpriv->cdo_mite_chan) {
 		mite_ack_linkc(devpriv->cdo_mite_chan);
-		mite_sync_output_dma(devpriv->cdo_mite_chan, s);
+		mite_sync_dma(devpriv->cdo_mite_chan, s);
 	}
 	spin_unlock_irqrestore(&devpriv->mite_channel_lock, flags);
 

drivers/staging/comedi/drivers/ni_pcidio.c

@@ -368,7 +368,7 @@ static int ni_pcidio_poll(struct comedi_device *dev, struct comedi_subdevice *s)
 	spin_lock_irqsave(&dev->spinlock, irq_flags);
 	spin_lock(&devpriv->mite_channel_lock);
 	if (devpriv->di_mite_chan)
-		mite_sync_input_dma(devpriv->di_mite_chan, s);
+		mite_sync_dma(devpriv->di_mite_chan, s);
 	spin_unlock(&devpriv->mite_channel_lock);
 	count = comedi_buf_n_bytes_ready(s);
 	spin_unlock_irqrestore(&dev->spinlock, irq_flags);
@@ -403,7 +403,7 @@ static irqreturn_t nidio_interrupt(int irq, void *d)
 		unsigned int m_status = mite_ack_linkc(devpriv->di_mite_chan);
 
 		if (m_status & CHSR_LINKC) {
-			mite_sync_input_dma(devpriv->di_mite_chan, s);
+			mite_sync_dma(devpriv->di_mite_chan, s);
 			/* XXX need to byteswap */
 		}
 		if (m_status & ~(CHSR_INT | CHSR_LINKC | CHSR_DONE | CHSR_DRDY |

drivers/staging/comedi/drivers/ni_tiocmd.c

@@ -430,7 +430,7 @@ void ni_tio_handle_interrupt(struct ni_gpct *counter,
 	spin_lock_irqsave(&counter->lock, flags);
 	if (counter->mite_chan) {
 		mite_ack_linkc(counter->mite_chan);
-		mite_sync_input_dma(counter->mite_chan, s);
+		mite_sync_dma(counter->mite_chan, s);
 	}
 	spin_unlock_irqrestore(&counter->lock, flags);
 }