staging: comedi: pcl816: use common function to setup dma

THe pcl816_ai_setup_dma() and pcl816_ai_setup_next_dma() functions are similar
other than the buffer switch and the inclusion of the "unread_samples" in
pcl818_ai_setup_next_dma() when calculating the dma size.

Merge these two functions by initializing the 'dma->cur_dma' in the callers
and passing '0' for the "unread_samples" when first starting the DMA.

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/pcl816.c b/drivers/staging/comedi/drivers/pcl816.c
index 88c89df717e5e75746333d2d600d3dfea2c66e90..da35edfccbc3bb5fb570ea0c606da236eb559e8f 100644 (file)
--- a/drivers/staging/comedi/drivers/pcl816.c
+++ b/drivers/staging/comedi/drivers/pcl816.c
@@ -142,47 +142,22 @@ static void pcl816_start_pacer(struct comedi_device *dev, bool load_counters)
 }
 
 static void pcl816_ai_setup_dma(struct comedi_device *dev,
-                               struct comedi_subdevice *s)
-{
-       struct pcl816_private *devpriv = dev->private;
-       struct comedi_isadma *dma = devpriv->dma;
-       struct comedi_isadma_desc *desc = &dma->desc[0];
-       unsigned int nsamples;
-
-       dma->cur_dma = 0;
-
-       /*
-        * Determine dma size based on the buffer maxsize and the number of
-        * samples remaining in the command.
-        */
-       nsamples = comedi_bytes_to_samples(s, desc->maxsize);
-       nsamples = comedi_nsamples_left(s, nsamples);
-       desc->size = comedi_samples_to_bytes(s, nsamples);
-       comedi_isadma_program(desc);
-}
-
-static void pcl816_ai_setup_next_dma(struct comedi_device *dev,
-                                    struct comedi_subdevice *s,
-                                    unsigned int unread_samples)
+                               struct comedi_subdevice *s,
+                               unsigned int unread_samples)
 {
        struct pcl816_private *devpriv = dev->private;
        struct comedi_isadma *dma = devpriv->dma;
-       struct comedi_isadma_desc *desc;
-       unsigned int max_samples;
+       struct comedi_isadma_desc *desc = &dma->desc[dma->cur_dma];
+       unsigned int max_samples = comedi_bytes_to_samples(s, desc->maxsize);
        unsigned int nsamples;
 
        comedi_isadma_disable(dma->chan);
 
-       dma->cur_dma = 1 - dma->cur_dma;
-       desc = &dma->desc[dma->cur_dma];
-
        /*
         * Determine dma size based on the buffer maxsize plus the number of
         * unread samples and the number of samples remaining in the command.
         */
-       max_samples = comedi_bytes_to_samples(s, desc->maxsize);
-       nsamples = max_samples + unread_samples;
-       nsamples = comedi_nsamples_left(s, nsamples);
+       nsamples = comedi_nsamples_left(s, max_samples + unread_samples);
        if (nsamples > unread_samples) {
                nsamples -= unread_samples;
                desc->size = comedi_samples_to_bytes(s, nsamples);
@@ -321,7 +296,9 @@ static irqreturn_t pcl816_interrupt(int irq, void *d)
        bufptr = devpriv->ai_poll_ptr;
        devpriv->ai_poll_ptr = 0;
 
-       pcl816_ai_setup_next_dma(dev, s, nsamples);
+       /* restart dma with the next buffer */
+       dma->cur_dma = 1 - dma->cur_dma;
+       pcl816_ai_setup_dma(dev, s, nsamples);
 
        transfer_from_dma_buf(dev, s, desc->virt_addr, bufptr, nsamples);
 
@@ -485,7 +462,9 @@ static int pcl816_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
        devpriv->ai_poll_ptr = 0;
        devpriv->ai_cmd_canceled = 0;
 
-       pcl816_ai_setup_dma(dev, s);
+       /* setup and enable dma for the first buffer */
+       dma->cur_dma = 0;
+       pcl816_ai_setup_dma(dev, s, 0);
 
        pcl816_start_pacer(dev, true);