staging: comedi: pcl816: introduce struct pcl816_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/pcl816.c b/drivers/staging/comedi/drivers/pcl816.c
index 4cff02a..49c1f17 100644 (file)
--- a/drivers/staging/comedi/drivers/pcl816.c
+++ b/drivers/staging/comedi/drivers/pcl816.c
@@ -113,13 +113,17 @@ static const struct pcl816_board boardtypes[] = {
        },
 };
 
+struct pcl816_dma_desc {
+       unsigned long virt_addr;        /* virtual address of DMA buffer */
+       unsigned int hw_addr;   /* hardware (bus) address of DMA buffer */
+};
+
 struct pcl816_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 pcl816_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 ai_poll_ptr;       /*  how many sampes transfer poll */
@@ -152,6 +156,7 @@ static void pcl816_ai_setup_dma(struct comedi_device *dev,
                                struct comedi_subdevice *s)
 {
        struct pcl816_private *devpriv = dev->private;
+       struct pcl816_dma_desc *dma = &devpriv->dma_desc[0];
        struct comedi_cmd *cmd = &s->async->cmd;
        unsigned int dma_flags;
        unsigned int bytes;
@@ -172,11 +177,11 @@ static void pcl816_ai_setup_dma(struct comedi_device *dev,
        } else
                devpriv->dma_runs_to_end = -1;
 
-       devpriv->next_dma_buf = 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, devpriv->hwdmaptr[0]);
+       set_dma_addr(devpriv->dma, dma->hw_addr);
        set_dma_count(devpriv->dma, bytes);
        release_dma_lock(dma_flags);
        enable_dma(devpriv->dma);
@@ -187,16 +192,17 @@ static void pcl816_ai_setup_next_dma(struct comedi_device *dev,
 {
        struct pcl816_private *devpriv = dev->private;
        struct comedi_cmd *cmd = &s->async->cmd;
+       struct pcl816_dma_desc *dma;
        unsigned long dma_flags;
 
        disable_dma(devpriv->dma);
        if (devpriv->dma_runs_to_end > -1 || cmd->stop_src == TRIG_NONE) {
                /* switch dma bufs */
-               devpriv->next_dma_buf = 1 - devpriv->next_dma_buf;
+               devpriv->cur_dma = 1 - devpriv->cur_dma;
+               dma = &devpriv->dma_desc[devpriv->cur_dma];
                set_dma_mode(devpriv->dma, DMA_MODE_READ);
                dma_flags = claim_dma_lock();
-               set_dma_addr(devpriv->dma,
-                            devpriv->hwdmaptr[devpriv->next_dma_buf]);
+               set_dma_addr(devpriv->dma, dma->hw_addr);
                if (devpriv->dma_runs_to_end)
                        set_dma_count(devpriv->dma, devpriv->hwdmasize);
                else
@@ -318,7 +324,7 @@ static irqreturn_t pcl816_interrupt(int irq, void *d)
        struct comedi_device *dev = d;
        struct comedi_subdevice *s = dev->read_subdev;
        struct pcl816_private *devpriv = dev->private;
-       unsigned short *ptr;
+       struct pcl816_dma_desc *dma = &devpriv->dma_desc[devpriv->cur_dma];
        unsigned int bufptr;
        unsigned int len;
 
@@ -333,15 +339,14 @@ static irqreturn_t pcl816_interrupt(int irq, void *d)
                return IRQ_HANDLED;
        }
 
-       ptr = (unsigned short *)devpriv->dmabuf[devpriv->next_dma_buf];
-
        pcl816_ai_setup_next_dma(dev, s);
 
        len = (devpriv->hwdmasize >> 1) - devpriv->ai_poll_ptr;
        bufptr = devpriv->ai_poll_ptr;
        devpriv->ai_poll_ptr = 0;
 
-       transfer_from_dma_buf(dev, s, ptr, bufptr, len);
+       transfer_from_dma_buf(dev, s, (unsigned short *)dma->virt_addr,
+                             bufptr, len);
 
        pcl816_ai_clear_eoc(dev);
 
@@ -521,6 +526,7 @@ static int pcl816_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
 static int pcl816_ai_poll(struct comedi_device *dev, struct comedi_subdevice *s)
 {
        struct pcl816_private *devpriv = dev->private;
+       struct pcl816_dma_desc *dma = &devpriv->dma_desc[devpriv->cur_dma];
        unsigned long flags;
        unsigned int top1, top2, i;
 
@@ -546,9 +552,7 @@ static int pcl816_ai_poll(struct comedi_device *dev, struct comedi_subdevice *s)
                return 0;
        }
 
-       transfer_from_dma_buf(dev, s,
-                             (unsigned short *)devpriv->dmabuf[devpriv->
-                                                               next_dma_buf],
+       transfer_from_dma_buf(dev, s, (unsigned short *)dma->virt_addr,
                              devpriv->ai_poll_ptr, top2);
 
        devpriv->ai_poll_ptr = top1;    /*  new buffer position */
@@ -661,6 +665,7 @@ static int pcl816_alloc_dma(struct comedi_device *dev,
                            unsigned int irq_num, unsigned int dma_chan)
 {
        struct pcl816_private *devpriv = dev->private;
+       struct pcl816_dma_desc *dma;
        int i;
 
        /*
@@ -692,14 +697,12 @@ static int pcl816_alloc_dma(struct comedi_device *dev,
        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->virt_addr = __get_dma_pages(GFP_KERNEL, devpriv->dmapages);
+               if (!dma->virt_addr)
                        return -ENOMEM;
-
-               devpriv->dmabuf[i] = dmabuf;
-               devpriv->hwdmaptr[i] = virt_to_bus((void *)dmabuf);
+               dma->hw_addr = virt_to_bus((void *)dma->virt_addr);
        }
        return 0;
 }
@@ -707,6 +710,7 @@ static int pcl816_alloc_dma(struct comedi_device *dev,
 static void pcl816_free_dma(struct comedi_device *dev)
 {
        struct pcl816_private *devpriv = dev->private;
+       struct pcl816_dma_desc *dma;
        int i;
 
        if (!devpriv)
@@ -715,8 +719,9 @@ static void pcl816_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->virt_addr)
+                       free_pages(dma->virt_addr, devpriv->dmapages);
        }
 }