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Commit 0afa6153 authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
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staging: comedi: ni_labpc_isadma: introduce labpc_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 f2c6bbe8

drivers/staging/comedi/drivers/ni_labpc_isadma.c

+18 −19
Original line number Diff line number Diff line
@@ -31,6 +31,19 @@ 
/* size in bytes of dma buffer */

#define LABPC_ISADMA_BUFFER_SIZE	0xff00



static void labpc_isadma_program(struct labpc_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);

}



static unsigned int labpc_isadma_disable(struct labpc_dma_desc *dma)

{

	unsigned long flags;
@@ -77,22 +90,15 @@ void labpc_setup_dma(struct comedi_device *dev, struct comedi_subdevice *s) 
	struct labpc_dma_desc *dma = &devpriv->dma_desc;

	struct comedi_cmd *cmd = &s->async->cmd;

	unsigned int sample_size = comedi_bytes_per_sample(s);

	unsigned long irq_flags;



	irq_flags = claim_dma_lock();

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

	 * count and address get set correctly */

	clear_dma_ff(dma->chan);

	set_dma_mode(dma->chan, DMA_MODE_READ);

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

	/* set appropriate size of transfer */

	dma->size = labpc_suggest_transfer_size(dev, s);

	if (cmd->stop_src == TRIG_COUNT &&

	    devpriv->count * sample_size < dma->size)

		dma->size = devpriv->count * sample_size;

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

	enable_dma(dma->chan);

	release_dma_lock(irq_flags);



	labpc_isadma_program(dma);



	/* set CMD3 bits for caller to enable DMA and interrupt */

	devpriv->cmd3 |= (CMD3_DMAEN | CMD3_DMATCINTEN);

}
@@ -145,18 +151,11 @@ static void handle_isa_dma(struct comedi_device *dev) 
{

	struct labpc_private *devpriv = dev->private;

	struct labpc_dma_desc *dma = &devpriv->dma_desc;

	unsigned long flags;



	labpc_drain_dma(dev);



	if (dma->size) {

		flags = claim_dma_lock();

		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);

	}

	if (dma->size)

		labpc_isadma_program(dma);



	/* clear dma tc interrupt */

	devpriv->write_byte(dev, 0x1, DMATC_CLEAR_REG);