staging: comedi: pcl818: introduce struct pcl818_dma_desc

For aesthetics, introduce a struct to hold the DMA descriptor data.

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/pcl818.c b/drivers/staging/comedi/drivers/pcl818.c
index beb03ec..f34c5cc 100644 (file)
--- a/drivers/staging/comedi/drivers/pcl818.c
+++ b/drivers/staging/comedi/drivers/pcl818.c
@@ -302,13 +302,17 @@ static const struct pcl818_board boardtypes[] = {
        },
 };
 
+struct pcl818_dma_desc {
+       unsigned long dmabuf;   /*  pointers to begin of DMA buffers */
+       unsigned int hwdmaptr;  /*  hardware address of DMA buffers */
+};
+
 struct pcl818_private {
        unsigned int dma;       /*  used DMA, 0=don't use DMA */
        unsigned int dmapages;
        unsigned int hwdmasize;
-       unsigned long dmabuf[2];        /*  pointers to begin of DMA buffers */
-       unsigned int hwdmaptr[2];       /*  hardware address of DMA buffers */
-       int next_dma_buf;       /*  which DMA buffer will be used next round */
+       struct pcl818_dma_desc dma_desc[2];
+       int cur_dma;
        long dma_runs_to_end;   /*  how many we must permorm DMA transfer to end of record */
        unsigned long last_dma_run;     /*  how many bytes we must transfer on last DMA page */
        unsigned int ns_min;    /*  manimal allowed delay between samples (in us) for actual card */
@@ -343,6 +347,7 @@ static void pcl818_ai_setup_dma(struct comedi_device *dev,
                                struct comedi_subdevice *s)
 {
        struct pcl818_private *devpriv = dev->private;
+       struct pcl818_dma_desc *dma = &devpriv->dma_desc[0];
        struct comedi_cmd *cmd = &s->async->cmd;
        unsigned int flags;
        unsigned int bytes;
@@ -358,11 +363,11 @@ static void pcl818_ai_setup_dma(struct comedi_device *dev,
                        bytes = devpriv->hwdmasize;
        }
 
-       devpriv->next_dma_buf = 0;
+       devpriv->cur_dma = 0;
        set_dma_mode(devpriv->dma, DMA_MODE_READ);
        flags = claim_dma_lock();
        clear_dma_ff(devpriv->dma);
-       set_dma_addr(devpriv->dma, devpriv->hwdmaptr[0]);
+       set_dma_addr(devpriv->dma, dma->hwdmaptr);
        set_dma_count(devpriv->dma, bytes);
        release_dma_lock(flags);
        enable_dma(devpriv->dma);
@@ -373,16 +378,17 @@ static void pcl818_ai_setup_next_dma(struct comedi_device *dev,
 {
        struct pcl818_private *devpriv = dev->private;
        struct comedi_cmd *cmd = &s->async->cmd;
+       struct pcl818_dma_desc *dma;
        unsigned long flags;
 
        disable_dma(devpriv->dma);
-       devpriv->next_dma_buf = 1 - devpriv->next_dma_buf;
+       devpriv->cur_dma = 1 - devpriv->cur_dma;
        if (devpriv->dma_runs_to_end > -1 || cmd->stop_src == TRIG_NONE) {
                /* switch dma bufs */
+               dma = &devpriv->dma_desc[devpriv->cur_dma];
                set_dma_mode(devpriv->dma, DMA_MODE_READ);
                flags = claim_dma_lock();
-               set_dma_addr(devpriv->dma,
-                            devpriv->hwdmaptr[devpriv->next_dma_buf]);
+               set_dma_addr(devpriv->dma, dma->hwdmaptr);
                if (devpriv->dma_runs_to_end || cmd->stop_src == TRIG_NONE)
                        set_dma_count(devpriv->dma, devpriv->hwdmasize);
                else
@@ -558,15 +564,14 @@ static void pcl818_handle_dma(struct comedi_device *dev,
                              struct comedi_subdevice *s)
 {
        struct pcl818_private *devpriv = dev->private;
-       unsigned short *ptr;
+       struct pcl818_dma_desc *dma = &devpriv->dma_desc[devpriv->cur_dma];
+       unsigned short *ptr = (unsigned short *)dma->dmabuf;
        unsigned int chan;
        unsigned int val;
        int i, len, bufptr;
 
        pcl818_ai_setup_next_dma(dev, s);
 
-       ptr = (unsigned short *)devpriv->dmabuf[1 - devpriv->next_dma_buf];
-
        len = devpriv->hwdmasize >> 1;
        bufptr = 0;
 
@@ -1057,6 +1062,7 @@ static void pcl818_set_ai_range_table(struct comedi_device *dev,
 static int pcl818_alloc_dma(struct comedi_device *dev, unsigned int dma_chan)
 {
        struct pcl818_private *devpriv = dev->private;
+       struct pcl818_dma_desc *dma;
        int i;
 
        if (!(dma_chan == 3 || dma_chan == 1))
@@ -1070,14 +1076,12 @@ static int pcl818_alloc_dma(struct comedi_device *dev, unsigned int dma_chan)
        devpriv->hwdmasize = (1 << devpriv->dmapages) * PAGE_SIZE;
 
        for (i = 0; i < 2; i++) {
-               unsigned long dmabuf;
+               dma = &devpriv->dma_desc[i];
 
-               dmabuf = __get_dma_pages(GFP_KERNEL, devpriv->dmapages);
-               if (!dmabuf)
+               dma->dmabuf = __get_dma_pages(GFP_KERNEL, devpriv->dmapages);
+               if (!dma->dmabuf)
                        return -ENOMEM;
-
-               devpriv->dmabuf[i] = dmabuf;
-               devpriv->hwdmaptr[i] = virt_to_bus((void *)dmabuf);
+               dma->hwdmaptr = virt_to_bus((void *)dma->dmabuf);
        }
        return 0;
 }
@@ -1085,6 +1089,7 @@ static int pcl818_alloc_dma(struct comedi_device *dev, unsigned int dma_chan)
 static void pcl818_free_dma(struct comedi_device *dev)
 {
        struct pcl818_private *devpriv = dev->private;
+       struct pcl818_dma_desc *dma;
        int i;
 
        if (!devpriv)
@@ -1093,8 +1098,9 @@ static void pcl818_free_dma(struct comedi_device *dev)
        if (devpriv->dma)
                free_dma(devpriv->dma);
        for (i = 0; i < 2; i++) {
-               if (devpriv->dmabuf[i])
-                       free_pages(devpriv->dmabuf[i], devpriv->dmapages);
+               dma = &devpriv->dma_desc[i];
+               if (dma->dmabuf)
+                       free_pages(dma->dmabuf, devpriv->dmapages);
        }
 }