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staging: comedi: ni_labpc_isadma: move dma programming out of labpc_drain_dma()

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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: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
H Hartley Sweeten 2015-01-13 10:16:41 -07:00 • committed by Greg Kroah-Hartman
parent 72ba5c1612
commit f2c6bbe8e0
1 changed files with 9 additions and 9 deletions
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18
drivers/staging/comedi/drivers/ni_labpc_isadma.c
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@ -109,7 +109,6 @@ void labpc_drain_dma(struct comedi_device *dev)
unsigned int residue; unsigned int residue;
unsigned int nsamples; unsigned int nsamples;
unsigned int leftover; unsigned int leftover;
unsigned long flags;
/* /*
* residue is the number of bytes left to be done on the dma * 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); dma->size = comedi_samples_to_bytes(s, leftover);
comedi_buf_write_samples(s, dma->virt_addr, nsamples); 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); 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_private *devpriv = dev->private;
struct labpc_dma_desc *dma = &devpriv->dma_desc; struct labpc_dma_desc *dma = &devpriv->dma_desc;
unsigned long flags;
labpc_drain_dma(dev); labpc_drain_dma(dev);
enable_dma(dma->chan); 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 */ /* clear dma tc interrupt */
devpriv->write_byte(dev, 0x1, DMATC_CLEAR_REG); devpriv->write_byte(dev, 0x1, DMATC_CLEAR_REG);