staging: comedi: pcl818: remove VIRT_TO_BUS dependancy

Use dma_{alloc,free}_coherent() to allocate and free the DMA buffers.
This removes the dependancy on VIRT_TO_BUS.
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/Kconfig

@@ -188,7 +188,7 @@ config COMEDI_PCL816
 
 config COMEDI_PCL818
 	tristate "Advantech PCL-718 and PCL-818 ISA card support"
-	depends on VIRT_TO_BUS && ISA_DMA_API
+	depends on ISA_DMA_API
 	---help---
 	  Enable support for Advantech PCL-818 ISA cards
 	  PCL-818L, PCL-818H, PCL-818HD, PCL-818HG, PCL-818 and PCL-718

drivers/staging/comedi/drivers/pcl818.c

@@ -303,13 +303,12 @@ static const struct pcl818_board boardtypes[] = {
 };
 
 struct pcl818_dma_desc {
-	unsigned long dmabuf;	/*  pointers to begin of DMA buffers */
-	unsigned int hwdmaptr;	/*  hardware address of DMA buffers */
+	void *virt_addr;	/* virtual address of DMA buffer */
+	dma_addr_t hw_addr;	/* hardware (bus) address of DMA buffer */
 };
 
 struct pcl818_private {
 	unsigned int dma;	/*  used DMA, 0=don't use DMA */
-	unsigned int dmapages;
 	unsigned int hwdmasize;
 	struct pcl818_dma_desc dma_desc[2];
 	int cur_dma;
@@ -367,7 +366,7 @@ static void pcl818_ai_setup_dma(struct comedi_device *dev,
 	set_dma_mode(devpriv->dma, DMA_MODE_READ);
 	flags = claim_dma_lock();
 	clear_dma_ff(devpriv->dma);
-	set_dma_addr(devpriv->dma, dma->hwdmaptr);
+	set_dma_addr(devpriv->dma, dma->hw_addr);
 	set_dma_count(devpriv->dma, bytes);
 	release_dma_lock(flags);
 	enable_dma(devpriv->dma);
@@ -388,7 +387,7 @@ static void pcl818_ai_setup_next_dma(struct comedi_device *dev,
 		dma = &devpriv->dma_desc[devpriv->cur_dma];
 		set_dma_mode(devpriv->dma, DMA_MODE_READ);
 		flags = claim_dma_lock();
-		set_dma_addr(devpriv->dma, dma->hwdmaptr);
+		set_dma_addr(devpriv->dma, dma->hw_addr);
 		if (devpriv->dma_runs_to_end || cmd->stop_src == TRIG_NONE)
 			set_dma_count(devpriv->dma, devpriv->hwdmasize);
 		else
@@ -565,7 +564,7 @@ static void pcl818_handle_dma(struct comedi_device *dev,
 {
 	struct pcl818_private *devpriv = dev->private;
 	struct pcl818_dma_desc *dma = &devpriv->dma_desc[devpriv->cur_dma];
-	unsigned short *ptr = (unsigned short *)dma->dmabuf;
+	unsigned short *ptr = dma->virt_addr;
 	unsigned int chan;
 	unsigned int val;
 	int i, len, bufptr;
@@ -1072,16 +1071,15 @@ static int pcl818_alloc_dma(struct comedi_device *dev, unsigned int dma_chan)
 		return 0;
 	devpriv->dma = dma_chan;
 
-	devpriv->dmapages = 2;	/* we need 16KB */
-	devpriv->hwdmasize = (1 << devpriv->dmapages) * PAGE_SIZE;
+	devpriv->hwdmasize = PAGE_SIZE * 4;	/* we need 16KB */
 
 	for (i = 0; i < 2; i++) {
 		dma = &devpriv->dma_desc[i];
 
-		dma->dmabuf = __get_dma_pages(GFP_KERNEL, devpriv->dmapages);
-		if (!dma->dmabuf)
+		dma->virt_addr = dma_alloc_coherent(NULL, devpriv->hwdmasize,
+						    &dma->hw_addr, GFP_KERNEL);
+		if (!dma->virt_addr)
 			return -ENOMEM;
-		dma->hwdmaptr = virt_to_bus((void *)dma->dmabuf);
 	}
 	return 0;
 }
@@ -1099,8 +1097,9 @@ static void pcl818_free_dma(struct comedi_device *dev)
 		free_dma(devpriv->dma);
 	for (i = 0; i < 2; i++) {
 		dma = &devpriv->dma_desc[i];
-		if (dma->dmabuf)
-			free_pages(dma->dmabuf, devpriv->dmapages);
+		if (dma->virt_addr)
+			dma_free_coherent(NULL, devpriv->hwdmasize,
+					  dma->virt_addr, dma->hw_addr);
 	}
 }