staging: comedi: pcl816: tidy up dma buffer allocation

This driver uses 2 buffers for DMA. Refactor the buffer allocation to
use a for loop to remove code duplication. Remove the dev_err() messages
when __get_dma_pages() fails and change the errno returned from -EBUSY
to -ENOMEM.

Both buffers are the same size so replace the 'dmapages' and 'hwdmasize'
arrays in the private data with variables to save a bit of space.

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 77bf996..29d4625 100644 (file)
--- a/drivers/staging/comedi/drivers/pcl816.c
+++ b/drivers/staging/comedi/drivers/pcl816.c
@@ -121,12 +121,11 @@ static const struct pcl816_board boardtypes[] = {
 };
 
 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 dmapages[2];       /*  len of DMA buffers in PAGE_SIZEs */
        unsigned int hwdmaptr[2];       /*  hardware address of DMA buffers */
-       unsigned int hwdmasize[2];      /*  len of DMA buffers in Bytes */
        unsigned int dmasamplsize;      /*  size in samples hwdmasize[0]/2 */
        int next_dma_buf;       /*  which DMA buffer will be used next round */
        long dma_runs_to_end;   /*  how many we must permorm DMA transfer to end of record */
@@ -339,13 +338,10 @@ static irqreturn_t interrupt_pcl816_ai_mode13_dma(int irq, void *d)
 /* clear_dma_ff (devpriv->dma); */
                set_dma_addr(devpriv->dma,
                             devpriv->hwdmaptr[devpriv->next_dma_buf]);
-               if (devpriv->dma_runs_to_end) {
-                       set_dma_count(devpriv->dma,
-                                     devpriv->hwdmasize[devpriv->
-                                                        next_dma_buf]);
-               } else {
+               if (devpriv->dma_runs_to_end)
+                       set_dma_count(devpriv->dma, devpriv->hwdmasize);
+               else
                        set_dma_count(devpriv->dma, devpriv->last_dma_run);
-               }
                release_dma_lock(dma_flags);
                enable_dma(devpriv->dma);
        }
@@ -355,7 +351,7 @@ static irqreturn_t interrupt_pcl816_ai_mode13_dma(int irq, void *d)
 
        ptr = (unsigned short *)devpriv->dmabuf[this_dma_buf];
 
-       len = (devpriv->hwdmasize[0] >> 1) - devpriv->ai_poll_ptr;
+       len = (devpriv->hwdmasize >> 1) - devpriv->ai_poll_ptr;
        bufptr = devpriv->ai_poll_ptr;
        devpriv->ai_poll_ptr = 0;
 
@@ -531,7 +527,7 @@ static int pcl816_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
                devpriv->ai_neverending = 1;
 
        if (devpriv->dma) {
-               bytes = devpriv->hwdmasize[0];
+               bytes = devpriv->hwdmasize;
                if (!devpriv->ai_neverending) {
                        /*  how many */
                        bytes = s->async->cmd.chanlist_len *
@@ -539,14 +535,13 @@ static int pcl816_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
                        sizeof(short);
 
                        /*  how many DMA pages we must fill */
-                       devpriv->dma_runs_to_end = bytes /
-                       devpriv->hwdmasize[0];
+                       devpriv->dma_runs_to_end = bytes / devpriv->hwdmasize;
 
                        /* on last dma transfer must be moved */
-                       devpriv->last_dma_run = bytes % devpriv->hwdmasize[0];
+                       devpriv->last_dma_run = bytes % devpriv->hwdmasize;
                        devpriv->dma_runs_to_end--;
                        if (devpriv->dma_runs_to_end >= 0)
-                               bytes = devpriv->hwdmasize[0];
+                               bytes = devpriv->hwdmasize;
                } else
                        devpriv->dma_runs_to_end = -1;
 
@@ -611,7 +606,7 @@ static int pcl816_ai_poll(struct comedi_device *dev, struct comedi_subdevice *s)
        }
 
        /*  where is now DMA in buffer */
-       top1 = devpriv->hwdmasize[0] - top1;
+       top1 = devpriv->hwdmasize - top1;
        top1 >>= 1;             /*  sample position */
        top2 = top1 - devpriv->ai_poll_ptr;
        if (top2 < 1) {         /*  no new samples */
@@ -843,10 +838,9 @@ static int pcl816_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 {
        const struct pcl816_board *board = comedi_board(dev);
        struct pcl816_private *devpriv;
-       int ret;
-       unsigned long pages;
-       /* int i; */
        struct comedi_subdevice *s;
+       int ret;
+       int i;
 
        ret = comedi_request_region(dev, it->options[0], 0x10);
        if (ret)
@@ -882,31 +876,19 @@ static int pcl816_attach(struct comedi_device *dev, struct comedi_devconfig *it)
                }
                devpriv->dma = it->options[2];
 
-               pages = 2;      /* we need 16KB */
-               devpriv->dmabuf[0] = __get_dma_pages(GFP_KERNEL, pages);
+               devpriv->dmapages = 2;  /* we need 16KB */
+               devpriv->hwdmasize = (1 << devpriv->dmapages) * PAGE_SIZE;
 
-               if (!devpriv->dmabuf[0]) {
-                       dev_err(dev->class_dev,
-                               "unable to allocate DMA buffer, FAIL!\n");
-                       /*
-                        * maybe experiment with try_to_free_pages()
-                        * will help ....
-                        */
-                       return -EBUSY;  /* no buffer :-( */
-               }
-               devpriv->dmapages[0] = pages;
-               devpriv->hwdmaptr[0] = virt_to_bus((void *)devpriv->dmabuf[0]);
-               devpriv->hwdmasize[0] = (1 << pages) * PAGE_SIZE;
+               for (i = 0; i < 2; i++) {
+                       unsigned long dmabuf;
 
-               devpriv->dmabuf[1] = __get_dma_pages(GFP_KERNEL, pages);
-               if (!devpriv->dmabuf[1]) {
-                       dev_err(dev->class_dev,
-                               "unable to allocate DMA buffer, FAIL!\n");
-                       return -EBUSY;
+                       dmabuf = __get_dma_pages(GFP_KERNEL, devpriv->dmapages);
+                       if (!dmabuf)
+                               return -ENOMEM;
+
+                       devpriv->dmabuf[i] = dmabuf;
+                       devpriv->hwdmaptr[i] = virt_to_bus((void *)dmabuf);
                }
-               devpriv->dmapages[1] = pages;
-               devpriv->hwdmaptr[1] = virt_to_bus((void *)devpriv->dmabuf[1]);
-               devpriv->hwdmasize[1] = (1 << pages) * PAGE_SIZE;
        }
 
        ret = comedi_alloc_subdevices(dev, 1);
@@ -968,9 +950,9 @@ static void pcl816_detach(struct comedi_device *dev)
                if (devpriv->dma)
                        free_dma(devpriv->dma);
                if (devpriv->dmabuf[0])
-                       free_pages(devpriv->dmabuf[0], devpriv->dmapages[0]);
+                       free_pages(devpriv->dmabuf[0], devpriv->dmapages);
                if (devpriv->dmabuf[1])
-                       free_pages(devpriv->dmabuf[1], devpriv->dmapages[1]);
+                       free_pages(devpriv->dmabuf[1], devpriv->dmapages);
        }
        comedi_legacy_detach(dev);
 }