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staging: comedi: pcl812: 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 14:27:28 -07:00 • committed by Greg Kroah-Hartman
parent 0f536336e4
commit 00ebe61736
1 changed files with 27 additions and 36 deletions
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63
drivers/staging/comedi/drivers/pcl812.c
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@ -522,10 +522,10 @@ struct pcl812_private {
unsigned int ai_act_scan; /* how many scans we finished */
unsigned int ai_chanlist[MAX_CHANLIST_LEN]; /* our copy of channel/range list */
unsigned int ai_data_len; /* len of data buffer */
unsigned int dmapages;
unsigned int hwdmasize;
unsigned long dmabuf[2]; /* PTR to DMA buf */
unsigned int dmapages[2]; /* how many pages we have allocated */
unsigned int hwdmaptr[2]; /* HW PTR to DMA buf */
unsigned int hwdmasize[2]; /* DMA buf size in bytes */
unsigned int dmabytestomove[2]; /* how many bytes DMA transfer */
int next_dma_buf; /* which buffer is next to use */
unsigned int dma_runs_to_end; /* how many times we must switch DMA buffers */
@ -814,14 +814,14 @@ static int pcl812_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
cmd->chanlist_len * sizeof(short);
devpriv->dma_runs_to_end = 1;
} else {
devpriv->dmabytestomove[0] = devpriv->hwdmasize[0];
devpriv->dmabytestomove[1] = devpriv->hwdmasize[1];
if (devpriv->ai_data_len < devpriv->hwdmasize[0])
devpriv->dmabytestomove[0] = devpriv->hwdmasize;
devpriv->dmabytestomove[1] = devpriv->hwdmasize;
if (devpriv->ai_data_len < devpriv->hwdmasize) {
devpriv->dmabytestomove[0] =
devpriv->ai_data_len;
if (devpriv->ai_data_len < devpriv->hwdmasize[1])
devpriv->dmabytestomove[1] =
devpriv->ai_data_len;
}
if (devpriv->ai_neverending) {
devpriv->dma_runs_to_end = 1;
} else {
@ -842,12 +842,12 @@ static int pcl812_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
devpriv->dma_runs_to_end--;
}
}
if (devpriv->dmabytestomove[0] > devpriv->hwdmasize[0]) {
devpriv->dmabytestomove[0] = devpriv->hwdmasize[0];
if (devpriv->dmabytestomove[0] > devpriv->hwdmasize) {
devpriv->dmabytestomove[0] = devpriv->hwdmasize;
devpriv->ai_eos = 0;
}
if (devpriv->dmabytestomove[1] > devpriv->hwdmasize[1]) {
devpriv->dmabytestomove[1] = devpriv->hwdmasize[1];
if (devpriv->dmabytestomove[1] > devpriv->hwdmasize) {
devpriv->dmabytestomove[1] = devpriv->hwdmasize;
devpriv->ai_eos = 0;
}
devpriv->next_dma_buf = 0;
@ -1303,10 +1303,11 @@ static int pcl812_attach(struct comedi_device *dev, struct comedi_devconfig *it)
{
const struct pcl812_board *board = comedi_board(dev);
struct pcl812_private *devpriv;
int ret, subdev;
unsigned long pages;
struct comedi_subdevice *s;
int n_subdevices;
int subdev;
int ret;
int i;
ret = comedi_request_region(dev, it->options[0], 0x10);
if (ret)
@ -1335,29 +1336,19 @@ static int pcl812_attach(struct comedi_device *dev, struct comedi_devconfig *it)
}
devpriv->dma = it->options[2];
pages = 1; /* we want 8KB */
devpriv->dmabuf[0] = __get_dma_pages(GFP_KERNEL, pages);
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 = 1; /* we want 8KB */
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);
}
devpriv->dmapages[0] = pages;
devpriv->hwdmaptr[0] = virt_to_bus((void *)devpriv->dmabuf[0]);
devpriv->hwdmasize[0] = PAGE_SIZE * (1 << pages);
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;
}
devpriv->dmapages[1] = pages;
devpriv->hwdmaptr[1] = virt_to_bus((void *)devpriv->dmabuf[1]);
devpriv->hwdmasize[1] = PAGE_SIZE * (1 << pages);
}
/* differential analog inputs? */
@ -1500,9 +1491,9 @@ static void pcl812_detach(struct comedi_device *dev)
if (devpriv) {
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);
if (devpriv->dma)
free_dma(devpriv->dma);
}