staging: comedi: pcl812: introduce pcl812_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/pcl812.c b/drivers/staging/comedi/drivers/pcl812.c
index 2c2e7dd9d3a1fdb962fb2053f0958488a3a676b1..6b38147cf2aef84e2c17154e3fe44032c59f9f2a 100644 (file)
--- a/drivers/staging/comedi/drivers/pcl812.c
+++ b/drivers/staging/comedi/drivers/pcl812.c
@@ -533,6 +533,20 @@ struct pcl812_private {
        unsigned int ai_eos:1;
 };
 
+static void pcl812_isadma_program(unsigned int dma_chan,
+                                 struct pcl812_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 void pcl812_start_pacer(struct comedi_device *dev, bool load_timers)
 {
        struct pcl812_private *devpriv = dev->private;
@@ -555,7 +569,6 @@ static void pcl812_ai_setup_dma(struct comedi_device *dev,
        struct pcl812_dma_desc *dma0 = &devpriv->dma_desc[0];
        struct pcl812_dma_desc *dma1 = &devpriv->dma_desc[1];
        struct comedi_cmd *cmd = &s->async->cmd;
-       unsigned int dma_flags;
        unsigned int bytes;
 
        /*  we use EOS, so adapt DMA buffer to one scan */
@@ -595,13 +608,8 @@ static void pcl812_ai_setup_dma(struct comedi_device *dev,
                devpriv->ai_eos = 0;
        }
        devpriv->cur_dma = 0;
-       set_dma_mode(devpriv->dma, DMA_MODE_READ);
-       dma_flags = claim_dma_lock();
-       clear_dma_ff(devpriv->dma);
-       set_dma_addr(devpriv->dma, dma0->hw_addr);
-       set_dma_count(devpriv->dma, dma0->size);
-       release_dma_lock(dma_flags);
-       enable_dma(devpriv->dma);
+
+       pcl812_isadma_program(devpriv->dma, dma0);
 }
 
 static void pcl812_ai_setup_next_dma(struct comedi_device *dev,
@@ -609,26 +617,19 @@ static void pcl812_ai_setup_next_dma(struct comedi_device *dev,
 {
        struct pcl812_private *devpriv = dev->private;
        struct pcl812_dma_desc *dma;
-       unsigned long dma_flags;
+
+       disable_dma(devpriv->dma);
 
        devpriv->cur_dma = 1 - devpriv->cur_dma;
        dma = &devpriv->dma_desc[devpriv->cur_dma];
-       disable_dma(devpriv->dma);
-       set_dma_mode(devpriv->dma, DMA_MODE_READ);
-       dma_flags = claim_dma_lock();
-       set_dma_addr(devpriv->dma, dma->hw_addr);
-       if (devpriv->ai_eos) {
-               set_dma_count(devpriv->dma, dma->size);
-       } else {
-               if (devpriv->dma_runs_to_end) {
-                       set_dma_count(devpriv->dma, dma->size);
-               } else {
-                       set_dma_count(devpriv->dma, devpriv->last_dma_run);
-               }
-               devpriv->dma_runs_to_end--;
+       if (!devpriv->ai_eos) {
+               if (devpriv->dma_runs_to_end)
+                       devpriv->dma_runs_to_end--;
+               else
+                       dma->size = devpriv->last_dma_run;
        }
-       release_dma_lock(dma_flags);
-       enable_dma(devpriv->dma);
+
+       pcl812_isadma_program(devpriv->dma, dma);
 }
 
 static void pcl812_ai_set_chan_range(struct comedi_device *dev,