staging: comedi: ni_labpc_isadma: introduce labpc_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/ni_labpc_isadma.c b/drivers/staging/comedi/drivers/ni_labpc_isadma.c
index af13f4b37daaf2d883a653cf227610f5034425d1..3100549b365c544f6957fa0f93a74118dc596b70 100644 (file)
--- a/drivers/staging/comedi/drivers/ni_labpc_isadma.c
+++ b/drivers/staging/comedi/drivers/ni_labpc_isadma.c
@@ -31,6 +31,19 @@
 /* size in bytes of dma buffer */
 #define LABPC_ISADMA_BUFFER_SIZE       0xff00
 
+static void labpc_isadma_program(struct labpc_dma_desc *dma)
+{
+       unsigned long flags;
+
+       flags = claim_dma_lock();
+       clear_dma_ff(dma->chan);
+       set_dma_mode(dma->chan, DMA_MODE_READ);
+       set_dma_addr(dma->chan, dma->hw_addr);
+       set_dma_count(dma->chan, dma->size);
+       enable_dma(dma->chan);
+       release_dma_lock(flags);
+}
+
 static unsigned int labpc_isadma_disable(struct labpc_dma_desc *dma)
 {
        unsigned long flags;
@@ -77,22 +90,15 @@ void labpc_setup_dma(struct comedi_device *dev, struct comedi_subdevice *s)
        struct labpc_dma_desc *dma = &devpriv->dma_desc;
        struct comedi_cmd *cmd = &s->async->cmd;
        unsigned int sample_size = comedi_bytes_per_sample(s);
-       unsigned long irq_flags;
 
-       irq_flags = claim_dma_lock();
-       /* clear flip-flop to make sure 2-byte registers for
-        * count and address get set correctly */
-       clear_dma_ff(dma->chan);
-       set_dma_mode(dma->chan, DMA_MODE_READ);
-       set_dma_addr(dma->chan, dma->hw_addr);
        /* set appropriate size of transfer */
        dma->size = labpc_suggest_transfer_size(dev, s);
        if (cmd->stop_src == TRIG_COUNT &&
            devpriv->count * sample_size < dma->size)
                dma->size = devpriv->count * sample_size;
-       set_dma_count(dma->chan, dma->size);
-       enable_dma(dma->chan);
-       release_dma_lock(irq_flags);
+
+       labpc_isadma_program(dma);
+
        /* set CMD3 bits for caller to enable DMA and interrupt */
        devpriv->cmd3 |= (CMD3_DMAEN | CMD3_DMATCINTEN);
 }
@@ -145,18 +151,11 @@ static void handle_isa_dma(struct comedi_device *dev)
 {
        struct labpc_private *devpriv = dev->private;
        struct labpc_dma_desc *dma = &devpriv->dma_desc;
-       unsigned long flags;
 
        labpc_drain_dma(dev);
 
-       if (dma->size) {
-               flags = claim_dma_lock();
-               set_dma_mode(dma->chan, DMA_MODE_READ);
-               set_dma_addr(dma->chan, dma->hw_addr);
-               set_dma_count(dma->chan, dma->size);
-               enable_dma(dma->chan);
-               release_dma_lock(flags);
-       }
+       if (dma->size)
+               labpc_isadma_program(dma);
 
        /* clear dma tc interrupt */
        devpriv->write_byte(dev, 0x1, DMATC_CLEAR_REG);