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Commit c92b0b29 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_program() 



Introduce a helper function to program the ISA DMA controller. Program
the ISA DMA 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 0156b06a

drivers/staging/comedi/drivers/ni_at_a2150.c

+21 −15
Original line number Diff line number Diff line
@@ -159,6 +159,19 @@ struct a2150_private { 
	int config_bits;	/*  config register bits */

};



static void a2150_isadma_program(struct a2150_dma_desc *dma)

{

	unsigned long flags;



	flags = claim_dma_lock();

	clear_dma_ff(dma->chan);

	set_dma_mode(dma->chan, DMA_MODE_READ);

	set_dma_addr(dma->chan, dma->hw_addr);

	set_dma_count(dma->chan, dma->size);

	enable_dma(dma->chan);

	release_dma_lock(flags);

}



/* interrupt service routine */

static irqreturn_t a2150_interrupt(int irq, void *d)

{
@@ -217,6 +230,7 @@ static irqreturn_t a2150_interrupt(int irq, void *d) 
	 * 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;

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

		num_points = devpriv->count;
@@ -252,12 +266,9 @@ static irqreturn_t a2150_interrupt(int irq, void *d) 
	}

	/* re-enable dma */

	if (leftover) {

		set_dma_addr(dma->chan, dma->hw_addr);

		set_dma_count(dma->chan,

			      comedi_samples_to_bytes(s, leftover));

		enable_dma(dma->chan);

		dma->size = comedi_samples_to_bytes(s, leftover);

		a2150_isadma_program(dma);

	}

	release_dma_lock(flags);



	comedi_handle_events(dev, s);
@@ -549,13 +560,10 @@ 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;



	/*  enable computer's dma */

	lock_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);

	set_dma_addr(dma->chan, dma->hw_addr);

	release_dma_lock(lock_flags);



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

#define ONE_THIRD_SECOND 333333333

	dma->size = comedi_bytes_per_sample(s) * cmd->chanlist_len *
@@ -565,9 +573,8 @@ static int a2150_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s) 
	if (dma->size < comedi_bytes_per_sample(s))

		dma->size = comedi_bytes_per_sample(s);

	dma->size -= dma->size % comedi_bytes_per_sample(s);

	set_dma_count(dma->chan, dma->size);

	enable_dma(dma->chan);

	release_dma_lock(lock_flags);



	a2150_isadma_program(dma);



	/* clear dma interrupt before enabling it, to try and get rid of that

	 * one spurious interrupt that has been happening */
@@ -724,7 +731,6 @@ static void a2150_alloc_irq_dma(struct comedi_device *dev, 
	devpriv->irq_dma_bits = IRQ_LVL_BITS(irq_num) | DMA_CHAN_BITS(dma_chan);



	disable_dma(dma_chan);

	set_dma_mode(dma_chan, DMA_MODE_READ);

}



static void a2150_free_dma(struct comedi_device *dev)