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Commit f5cc425a authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
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staging: comedi: pcl818: 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 55b95f14

drivers/staging/comedi/drivers/pcl818.c

+28 −33
Original line number Diff line number Diff line
@@ -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);

}