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Commit 00ebe617 authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
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staging: comedi: pcl812: 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: default avatarH Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: default avatarIan Abbott <abbotti@mev.co.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 0f536336

drivers/staging/comedi/drivers/pcl812.c

+27 −36
Original line number Original line Diff line number Diff line
@@ -522,10 +522,10 @@ struct pcl812_private { 
	unsigned int ai_act_scan;	/*  how many scans we finished */

	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_chanlist[MAX_CHANLIST_LEN];	/*  our copy of channel/range list */

	unsigned int ai_data_len;	/*  len of data buffer */

	unsigned int ai_data_len;	/*  len of data buffer */

	unsigned int dmapages;

	unsigned int hwdmasize;

	unsigned long dmabuf[2];	/*  PTR to DMA buf */

	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 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 */

	unsigned int dmabytestomove[2];	/*  how many bytes DMA transfer */

	int next_dma_buf;	/*  which buffer is next to use */

	int next_dma_buf;	/*  which buffer is next to use */

	unsigned int dma_runs_to_end;	/*  how many times we must switch DMA buffers */

	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);

			    cmd->chanlist_len * sizeof(short);

			devpriv->dma_runs_to_end = 1;

			devpriv->dma_runs_to_end = 1;

		} else {

		} else {

			devpriv->dmabytestomove[0] = devpriv->hwdmasize[0];

			devpriv->dmabytestomove[0] = devpriv->hwdmasize;

			devpriv->dmabytestomove[1] = devpriv->hwdmasize[1];

			devpriv->dmabytestomove[1] = devpriv->hwdmasize;

			if (devpriv->ai_data_len < devpriv->hwdmasize[0])

			if (devpriv->ai_data_len < devpriv->hwdmasize) {

				devpriv->dmabytestomove[0] =

				devpriv->dmabytestomove[0] =

				    devpriv->ai_data_len;

				    devpriv->ai_data_len;

			if (devpriv->ai_data_len < devpriv->hwdmasize[1])

				devpriv->dmabytestomove[1] =

				devpriv->dmabytestomove[1] =

				    devpriv->ai_data_len;

				    devpriv->ai_data_len;

			}

			if (devpriv->ai_neverending) {

			if (devpriv->ai_neverending) {

				devpriv->dma_runs_to_end = 1;

				devpriv->dma_runs_to_end = 1;

			} else {

			} else {
@@ -842,12 +842,12 @@ static int pcl812_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s) 
				devpriv->dma_runs_to_end--;

				devpriv->dma_runs_to_end--;

			}

			}

		}

		}

		if (devpriv->dmabytestomove[0] > devpriv->hwdmasize[0]) {

		if (devpriv->dmabytestomove[0] > devpriv->hwdmasize) {

			devpriv->dmabytestomove[0] = devpriv->hwdmasize[0];

			devpriv->dmabytestomove[0] = devpriv->hwdmasize;

			devpriv->ai_eos = 0;

			devpriv->ai_eos = 0;

		}

		}

		if (devpriv->dmabytestomove[1] > devpriv->hwdmasize[1]) {

		if (devpriv->dmabytestomove[1] > devpriv->hwdmasize) {

			devpriv->dmabytestomove[1] = devpriv->hwdmasize[1];

			devpriv->dmabytestomove[1] = devpriv->hwdmasize;

			devpriv->ai_eos = 0;

			devpriv->ai_eos = 0;

		}

		}

		devpriv->next_dma_buf = 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);

	const struct pcl812_board *board = comedi_board(dev);

	struct pcl812_private *devpriv;

	struct pcl812_private *devpriv;

	int ret, subdev;

	unsigned long pages;

	struct comedi_subdevice *s;

	struct comedi_subdevice *s;

	int n_subdevices;

	int n_subdevices;

	int subdev;

	int ret;

	int i;





	ret = comedi_request_region(dev, it->options[0], 0x10);

	ret = comedi_request_region(dev, it->options[0], 0x10);

	if (ret)

	if (ret)
@@ -1335,29 +1336,19 @@ static int pcl812_attach(struct comedi_device *dev, struct comedi_devconfig *it) 
		}

		}

		devpriv->dma = it->options[2];

		devpriv->dma = it->options[2];





		pages = 1;	/* we want 8KB */

		devpriv->dmapages = 1;	/* we want 8KB */

		devpriv->dmabuf[0] = __get_dma_pages(GFP_KERNEL, pages);

		devpriv->hwdmasize = (1 << devpriv->dmapages) * PAGE_SIZE;

		if (!devpriv->dmabuf[0]) {



			dev_err(dev->class_dev,

		for (i = 0; i < 2; i++) {

				"unable to allocate DMA buffer, FAIL!\n");

			unsigned long dmabuf;

			/*



			 * maybe experiment with try_to_free_pages()

			dmabuf =  __get_dma_pages(GFP_KERNEL, devpriv->dmapages);

			 * will help ....

			if (!dmabuf)

			 */

				return -ENOMEM;

			return -EBUSY;	/* no buffer :-( */



		}

			devpriv->dmabuf[i] = dmabuf;

		devpriv->dmapages[0] = pages;

			devpriv->hwdmaptr[i] = virt_to_bus((void *)dmabuf);

		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? */

	/* differential analog inputs? */
@@ -1500,9 +1491,9 @@ static void pcl812_detach(struct comedi_device *dev) 




	if (devpriv) {

	if (devpriv) {

		if (devpriv->dmabuf[0])

		if (devpriv->dmabuf[0])

			free_pages(devpriv->dmabuf[0], devpriv->dmapages[0]);

			free_pages(devpriv->dmabuf[0], devpriv->dmapages);

		if (devpriv->dmabuf[1])

		if (devpriv->dmabuf[1])

			free_pages(devpriv->dmabuf[1], devpriv->dmapages[1]);

			free_pages(devpriv->dmabuf[1], devpriv->dmapages);

		if (devpriv->dma)

		if (devpriv->dma)

			free_dma(devpriv->dma);

			free_dma(devpriv->dma);

	}

	}