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Commit 55b95f14 authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
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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: 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 00ebe617

drivers/staging/comedi/drivers/pcl816.c

+25 −43
Original line number Diff line number Diff line
@@ -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);

}