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Commit 10f3a2dc authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
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staging: comedi: ni_at_a2150: introduce a2150_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 c92b0b29

drivers/staging/comedi/drivers/ni_at_a2150.c

+23 −19
Original line number Diff line number Diff line
@@ -172,12 +172,24 @@ static void a2150_isadma_program(struct a2150_dma_desc *dma) 
	release_dma_lock(flags);

}



static unsigned int a2150_isadma_disable(struct a2150_dma_desc *dma)

{

	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;

}



/* interrupt service routine */

static irqreturn_t a2150_interrupt(int irq, void *d)

{

	int i;

	int status;

	unsigned long flags;

	struct comedi_device *dev = d;

	struct a2150_private *devpriv = dev->private;

	struct a2150_dma_desc *dma = &devpriv->dma_desc;
@@ -217,21 +229,16 @@ static irqreturn_t a2150_interrupt(int irq, void *d) 
		return IRQ_HANDLED;

	}



	flags = claim_dma_lock();

	disable_dma(dma->chan);

	/* clear flip-flop to make sure 2-byte registers for

	 * count and address get set correctly */

	clear_dma_ff(dma->chan);



	/*  figure out how many points to read */

	max_points = comedi_bytes_to_samples(s, dma->size);

	/* residue is the number of points left to be done on the dma

	/*

	 * residue is the number of bytes left to be done on the dma

	 * transfer.  It should always be zero at this point unless

	 * the stop_src is set to external triggering.

	 */

	residue = comedi_bytes_to_samples(s, get_dma_residue(dma->chan));

	release_dma_lock(flags);

	num_points = max_points - residue;

	residue = a2150_isadma_disable(dma);



	/*  figure out how many points to read */

	max_points = comedi_bytes_to_samples(s, dma->size);

	num_points = max_points - comedi_bytes_to_samples(s, residue);

	if (devpriv->count < num_points && cmd->stop_src == TRIG_COUNT)

		num_points = devpriv->count;
@@ -288,7 +295,7 @@ static int a2150_cancel(struct comedi_device *dev, struct comedi_subdevice *s) 
	outw(devpriv->irq_dma_bits, dev->iobase + IRQ_DMA_CNTRL_REG);



	/*  disable computer's dma */

	disable_dma(dma->chan);

	a2150_isadma_disable(dma);



	/*  clear fifo and reset triggering circuitry */

	outw(0, dev->iobase + FIFO_RESET_REG);
@@ -524,7 +531,6 @@ static int a2150_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s) 
	struct comedi_async *async = s->async;

	struct comedi_cmd *cmd = &async->cmd;

	unsigned long timer_base = dev->iobase + I8253_BASE_REG;

	unsigned long lock_flags;

	unsigned int old_config_bits = devpriv->config_bits;

	unsigned int trigger_bits;
@@ -560,9 +566,7 @@ static int a2150_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s) 
	/*  initialize number of samples remaining */

	devpriv->count = cmd->stop_arg * cmd->chanlist_len;



	lock_flags = claim_dma_lock();

	disable_dma(dma->chan);

	release_dma_lock(lock_flags);

	a2150_isadma_disable(dma);



	/*  set size of transfer to fill in 1/3 second */

#define ONE_THIRD_SECOND 333333333
@@ -730,7 +734,7 @@ static void a2150_alloc_irq_dma(struct comedi_device *dev, 
	dma->chan = dma_chan;

	devpriv->irq_dma_bits = IRQ_LVL_BITS(irq_num) | DMA_CHAN_BITS(dma_chan);



	disable_dma(dma_chan);

	a2150_isadma_disable(dma);

}



static void a2150_free_dma(struct comedi_device *dev)