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staging: comedi: pcl818: 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 14:27:30 -07:00 committed by Greg Kroah-Hartman
parent 55b95f1430
commit f5cc425afe
1 changed files with 28 additions and 33 deletions
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61
drivers/staging/comedi/drivers/pcl818.c
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@ -320,12 +320,11 @@ static const struct pcl818_board boardtypes[] = {
};
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 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 */
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 */
unsigned long last_dma_run; /* how many bytes we must transfer on last DMA page */
@ -584,13 +583,10 @@ static irqreturn_t interrupt_pcl818_ai_mode13_dma(int irq, void *d)
flags = claim_dma_lock();
set_dma_addr(devpriv->dma,
devpriv->hwdmaptr[devpriv->next_dma_buf]);
if (devpriv->dma_runs_to_end || devpriv->neverending_ai) {
set_dma_count(devpriv->dma,
devpriv->hwdmasize[devpriv->
next_dma_buf]);
} else {
if (devpriv->dma_runs_to_end || devpriv->neverending_ai)
set_dma_count(devpriv->dma, devpriv->hwdmasize);
else
set_dma_count(devpriv->dma, devpriv->last_dma_run);
}
release_dma_lock(flags);
enable_dma(devpriv->dma);
}
@ -599,7 +595,7 @@ static irqreturn_t interrupt_pcl818_ai_mode13_dma(int irq, void *d)
outb(0, dev->iobase + PCL818_CLRINT); /* clear INT request */
ptr = (unsigned short *)devpriv->dmabuf[1 - devpriv->next_dma_buf];
len = devpriv->hwdmasize[0] >> 1;
len = devpriv->hwdmasize >> 1;
bufptr = 0;
for (i = 0; i < len; i++) {
@ -795,14 +791,14 @@ static void pcl818_ai_mode13dma_int(int mode, struct comedi_device *dev,
unsigned int bytes;
disable_dma(devpriv->dma); /* disable dma */
bytes = devpriv->hwdmasize[0];
bytes = devpriv->hwdmasize;
if (!devpriv->neverending_ai) {
bytes = cmd->chanlist_len * cmd->stop_arg * sizeof(short); /* how many */
devpriv->dma_runs_to_end = bytes / devpriv->hwdmasize[0]; /* how many DMA pages we must fiil */
devpriv->last_dma_run = bytes % devpriv->hwdmasize[0]; /* on last dma transfer must be moved */
bytes = cmd->chanlist_len * cmd->stop_arg * sizeof(short);
devpriv->dma_runs_to_end = bytes / devpriv->hwdmasize;
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;
}
devpriv->next_dma_buf = 0;
@ -1308,9 +1304,9 @@ static int pcl818_attach(struct comedi_device *dev, struct comedi_devconfig *it)
{
const struct pcl818_board *board = comedi_board(dev);
struct pcl818_private *devpriv;
int ret;
unsigned long pages;
struct comedi_subdevice *s;
int ret;
int i;
devpriv = comedi_alloc_devpriv(dev, sizeof(*devpriv));
if (!devpriv)
@ -1353,20 +1349,19 @@ static int pcl818_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);
if (!devpriv->dmabuf[0])
/* 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;
devpriv->dmabuf[1] = __get_dma_pages(GFP_KERNEL, pages);
if (!devpriv->dmabuf[1])
return -EBUSY;
devpriv->dmapages[1] = pages;
devpriv->hwdmaptr[1] = virt_to_bus((void *)devpriv->dmabuf[1]);
devpriv->hwdmasize[1] = (1 << pages) * PAGE_SIZE;
devpriv->dmapages = 2; /* we need 16KB */
devpriv->hwdmasize = (1 << devpriv->dmapages) * PAGE_SIZE;
for (i = 0; i < 2; i++) {
unsigned long dmabuf;
dmabuf = __get_dma_pages(GFP_KERNEL, devpriv->dmapages);
if (!dmabuf)
return -ENOMEM;
devpriv->dmabuf[i] = dmabuf;
devpriv->hwdmaptr[i] = virt_to_bus((void *)dmabuf);
}
}
ret = comedi_alloc_subdevices(dev, 4);
@ -1468,9 +1463,9 @@ static void pcl818_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);
}