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Commit f2c6bbe8 authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
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staging: comedi: ni_labpc_isadma: move dma programming out of labpc_drain_dma() 



The external caller of labpc_drain_dma() does not enable the DMA transfer. Only
the call from handle_isa_dma() results in the programmed DMA operation getting
enabled.

For aesthetics, move the dma programming to handle_isa_dma(). Make sure the
DMA operation would actually do something (dma->size != 0) before programming
it to avoid enabling the DMA at the end of a stop_src == TRIG_COUNT command.

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 72ba5c16

drivers/staging/comedi/drivers/ni_labpc_isadma.c

+9 −9
Original line number Diff line number Diff line
@@ -109,7 +109,6 @@ void labpc_drain_dma(struct comedi_device *dev) 
	unsigned int residue;

	unsigned int nsamples;

	unsigned int leftover;

	unsigned long flags;



	/*

	 * residue is the number of bytes left to be done on the dma
@@ -139,13 +138,6 @@ void labpc_drain_dma(struct comedi_device *dev) 
	dma->size = comedi_samples_to_bytes(s, leftover);



	comedi_buf_write_samples(s, dma->virt_addr, nsamples);



	/* set address and count for next transfer */

	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);

	release_dma_lock(flags);

}

EXPORT_SYMBOL_GPL(labpc_drain_dma);
@@ -153,10 +145,18 @@ 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);

	}



	/* clear dma tc interrupt */

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