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staging: comedi: pcl816: tidy up dma buffer allocation

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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>
This commit is contained in:
H Hartley Sweeten 2014-02-17 14:27:29 -07:00 committed by Greg Kroah-Hartman
parent 00ebe61736
commit 55b95f1430
1 changed files with 25 additions and 43 deletions
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68
drivers/staging/comedi/drivers/pcl816.c
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@ -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);
}