staging: comedi: dt282x: introduce dt282x_isadma_program()

Introduce a helper function to program the ISA DMA controller. Program
the ISA DMA as described in Documentation/DMA-ISA-LPC.txt.

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>

diff --git a/drivers/staging/comedi/drivers/dt282x.c b/drivers/staging/comedi/drivers/dt282x.c
index f24ad6684bf5ddfd0eb32c23dbac3f195c9a4c1e..2d01c6cfbb4d9aa6ca2ad42de51bd51e160bdf8e 100644 (file)
--- a/drivers/staging/comedi/drivers/dt282x.c
+++ b/drivers/staging/comedi/drivers/dt282x.c
@@ -305,6 +305,7 @@ struct dt282x_dma_desc {
        void *virt_addr;        /* virtual address of DMA buffer */
        dma_addr_t hw_addr;     /* hardware (bus) address of DMA buffer */
        unsigned int size;      /* transfer size (in bytes) */
+       char mode;              /* DMA_MODE_* */
 };
 
 struct dt282x_private {
@@ -325,11 +326,23 @@ struct dt282x_private {
        int dma_dir;
 };
 
+static void dt282x_isadma_program(struct dt282x_dma_desc *dma)
+{
+       unsigned long flags;
+
+       flags = claim_dma_lock();
+       clear_dma_ff(dma->chan);
+       set_dma_mode(dma->chan, dma->mode);
+       set_dma_addr(dma->chan, dma->hw_addr);
+       set_dma_count(dma->chan, dma->size);
+       enable_dma(dma->chan);
+       release_dma_lock(flags);
+}
+
 static int dt282x_prep_ai_dma(struct comedi_device *dev, int dma_index, int n)
 {
        struct dt282x_private *devpriv = dev->private;
        struct dt282x_dma_desc *dma = &devpriv->dma_desc[dma_index];
-       unsigned long flags;
 
        if (!devpriv->ntrig)
                return 0;
@@ -341,15 +354,9 @@ static int dt282x_prep_ai_dma(struct comedi_device *dev, int dma_index, int n)
        devpriv->ntrig -= n / 2;
 
        dma->size = n;
+       dma->mode = DMA_MODE_READ;
 
-       set_dma_mode(dma->chan, DMA_MODE_READ);
-       flags = claim_dma_lock();
-       clear_dma_ff(dma->chan);
-       set_dma_addr(dma->chan, dma->hw_addr);
-       set_dma_count(dma->chan, dma->size);
-       release_dma_lock(flags);
-
-       enable_dma(dma->chan);
+       dt282x_isadma_program(dma);
 
        return n;
 }
@@ -358,18 +365,11 @@ static int dt282x_prep_ao_dma(struct comedi_device *dev, int dma_index, int n)
 {
        struct dt282x_private *devpriv = dev->private;
        struct dt282x_dma_desc *dma = &devpriv->dma_desc[dma_index];
-       unsigned long flags;
 
        dma->size = n;
+       dma->mode = DMA_MODE_WRITE;
 
-       set_dma_mode(dma->chan, DMA_MODE_WRITE);
-       flags = claim_dma_lock();
-       clear_dma_ff(dma->chan);
-       set_dma_addr(dma->chan, dma->hw_addr);
-       set_dma_count(dma->chan, dma->size);
-       release_dma_lock(flags);
-
-       enable_dma(dma->chan);
+       dt282x_isadma_program(dma);
 
        return n;
 }