staging: comedi: das1800: introduce das1800_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/das1800.c b/drivers/staging/comedi/drivers/das1800.c
index c8ad7dd1ac2118e7ab46751ae56ecddadc0324a5..6df58cda7d3293b8ff03e6a1164df66391d1e256 100644 (file)
--- a/drivers/staging/comedi/drivers/das1800.c
+++ b/drivers/staging/comedi/drivers/das1800.c
@@ -452,6 +452,19 @@ static const struct comedi_lrange range_ao_2 = {
 };
 */
 
+static void das1800_isadma_program(struct das1800_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 inline uint16_t munge_bipolar_sample(const struct comedi_device *dev,
                                            uint16_t sample)
 {
@@ -571,12 +584,11 @@ static void das1800_handle_dma(struct comedi_device *dev,
 
        flags = claim_dma_lock();
        das1800_flush_dma_channel(dev, s, dma);
-       /*  re-enable  dma channel */
-       set_dma_addr(dma->chan, dma->hw_addr);
-       set_dma_count(dma->chan, dma->size);
-       enable_dma(dma->chan);
        release_dma_lock(flags);
 
+       /* re-enable dma channel */
+       das1800_isadma_program(dma);
+
        if (status & DMATC) {
                /*  clear DMATC interrupt bit */
                outb(CLEAR_INTR_MASK & ~DMATC, dev->iobase + DAS1800_STATUS);
@@ -998,8 +1010,6 @@ static void setup_dma(struct comedi_device *dev, const struct comedi_cmd *cmd)
 {
        struct das1800_private *devpriv = dev->private;
        struct das1800_dma_desc *dma = &devpriv->dma_desc[0];
-       unsigned long lock_flags;
-       const int dual_dma = devpriv->irq_dma_bits & DMA_DUAL;
        unsigned int bytes;
 
        if ((devpriv->irq_dma_bits & DMA_ENABLED) == 0)
@@ -1011,29 +1021,14 @@ static void setup_dma(struct comedi_device *dev, const struct comedi_cmd *cmd)
        bytes = suggest_transfer_size(cmd);
 
        dma->size = bytes;
-       lock_flags = claim_dma_lock();
-       disable_dma(dma->chan);
-       /* clear flip-flop to make sure 2-byte registers for
-        * count and address get set correctly */
-       clear_dma_ff(dma->chan);
-       set_dma_addr(dma->chan, dma->hw_addr);
-       /*  set appropriate size of transfer */
-       set_dma_count(dma->chan, dma->size);
-       enable_dma(dma->chan);
-       /*  set up dual dma if appropriate */
-       if (dual_dma) {
+       das1800_isadma_program(dma);
+
+       /* set up dual dma if appropriate */
+       if (devpriv->irq_dma_bits & DMA_DUAL) {
                dma = &devpriv->dma_desc[1];
                dma->size = bytes;
-               disable_dma(dma->chan);
-               /* clear flip-flop to make sure 2-byte registers for
-                * count and address get set correctly */
-               clear_dma_ff(dma->chan);
-               set_dma_addr(dma->chan, dma->hw_addr);
-               /*  set appropriate size of transfer */
-               set_dma_count(dma->chan, dma->size);
-               enable_dma(dma->chan);
+               das1800_isadma_program(dma);
        }
-       release_dma_lock(lock_flags);
 }
 
 /* programs channel/gain list into card */
@@ -1299,7 +1294,6 @@ static int das1800_init_dma(struct comedi_device *dev,
 
                flags = claim_dma_lock();
                disable_dma(dma->chan);
-               set_dma_mode(dma->chan, DMA_MODE_READ);
                release_dma_lock(flags);
        }