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Commit a1ce5f03 authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
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staging: comedi: das16: introduce das16_isadma_disable() 



Introduce a helper function to disable and the ISA DMA controller and
return the residue as described in Documentation/DMA-ISA-LPC.txt.

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 0196285e

drivers/staging/comedi/drivers/das16.c

+20 −13
Original line number Original line Diff line number Diff line
@@ -475,6 +475,19 @@ static void das16_isadma_program(unsigned int dma_chan, 
	release_dma_lock(flags);

	release_dma_lock(flags);

}

}





static unsigned int das16_isadma_disable(unsigned int dma_chan)

{

	unsigned long flags;

	unsigned int residue;



	flags = claim_dma_lock();

	disable_dma(dma_chan);

	residue = get_dma_residue(dma_chan);

	release_dma_lock(flags);



	return residue;

}



static void das16_ai_enable(struct comedi_device *dev,

static void das16_ai_enable(struct comedi_device *dev,

			    unsigned int mode, unsigned int src)

			    unsigned int mode, unsigned int src)

{

{
@@ -514,23 +527,24 @@ static int disable_dma_on_even(struct comedi_device *dev) 
	struct das16_private_struct *devpriv = dev->private;

	struct das16_private_struct *devpriv = dev->private;

	static const int disable_limit = 100;

	static const int disable_limit = 100;

	static const int enable_timeout = 100;

	static const int enable_timeout = 100;

	int residue;

	unsigned long flags;

	unsigned int residue;

	int new_residue;

	int new_residue;

	int i;

	int i;

	int j;

	int j;





	disable_dma(devpriv->dma_chan);

	residue = das16_isadma_disable(devpriv->dma_chan);

	residue = get_dma_residue(devpriv->dma_chan);

	for (i = 0; i < disable_limit && (residue % 2); ++i) {

	for (i = 0; i < disable_limit && (residue % 2); ++i) {

		flags = claim_dma_lock();

		enable_dma(devpriv->dma_chan);

		enable_dma(devpriv->dma_chan);

		for (j = 0; j < enable_timeout; ++j) {

		for (j = 0; j < enable_timeout; ++j) {

			udelay(2);

			udelay(2);

			new_residue = get_dma_residue(devpriv->dma_chan);

			new_residue = get_dma_residue(devpriv->dma_chan);

			release_dma_lock(flags);

			if (new_residue != residue)

			if (new_residue != residue)

				break;

				break;

		}

		}

		disable_dma(devpriv->dma_chan);

		residue = das16_isadma_disable(devpriv->dma_chan);

		residue = get_dma_residue(devpriv->dma_chan);

	}

	}

	if (i == disable_limit) {

	if (i == disable_limit) {

		dev_err(dev->class_dev,

		dev_err(dev->class_dev,
@@ -548,7 +562,6 @@ static void das16_interrupt(struct comedi_device *dev) 
	struct das16_dma_desc *dma = &devpriv->dma_desc[devpriv->cur_dma];

	struct das16_dma_desc *dma = &devpriv->dma_desc[devpriv->cur_dma];

	struct das16_dma_desc *nxt_dma;

	struct das16_dma_desc *nxt_dma;

	unsigned long spin_flags;

	unsigned long spin_flags;

	unsigned long dma_flags;

	unsigned int nsamples;

	unsigned int nsamples;

	int num_bytes, residue;

	int num_bytes, residue;
@@ -558,10 +571,7 @@ static void das16_interrupt(struct comedi_device *dev) 
		return;

		return;

	}

	}





	dma_flags = claim_dma_lock();

	clear_dma_ff(devpriv->dma_chan);

	residue = disable_dma_on_even(dev);

	residue = disable_dma_on_even(dev);

	release_dma_lock(dma_flags);





	/*  figure out how many points to read */

	/*  figure out how many points to read */

	if (residue > dma->size) {

	if (residue > dma->size) {
@@ -1001,7 +1011,6 @@ static int das16_alloc_dma(struct comedi_device *dev, unsigned int dma_chan) 
{

{

	struct das16_private_struct *devpriv = dev->private;

	struct das16_private_struct *devpriv = dev->private;

	struct das16_dma_desc *dma;

	struct das16_dma_desc *dma;

	unsigned long flags;

	int i;

	int i;





	if (!(dma_chan == 1 || dma_chan == 3))

	if (!(dma_chan == 1 || dma_chan == 3))
@@ -1020,9 +1029,7 @@ static int das16_alloc_dma(struct comedi_device *dev, unsigned int dma_chan) 
			return -ENOMEM;

			return -ENOMEM;

	}

	}





	flags = claim_dma_lock();

	das16_isadma_disable(devpriv->dma_chan);

	disable_dma(devpriv->dma_chan);

	release_dma_lock(flags);





	init_timer(&devpriv->timer);

	init_timer(&devpriv->timer);

	devpriv->timer.function = das16_timer_interrupt;

	devpriv->timer.function = das16_timer_interrupt;