diff options
| author | H Hartley Sweeten <hsweeten@visionengravers.com> | 2015-01-13 10:16:41 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-01-17 14:31:31 -0800 |
| commit | f2c6bbe8e02d589a02282c2a260f912ab4f12376 (patch) | |
| tree | d5529a02090260db6352a793a25107fc0a1b4986 /drivers/staging/comedi | |
| parent | 72ba5c1612f5ea7f907290903e8fc24ed94aec13 (diff) | |
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: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/staging/comedi')
| -rw-r--r-- | drivers/staging/comedi/drivers/ni_labpc_isadma.c | 18 |
1 files changed, 9 insertions, 9 deletions
diff --git a/drivers/staging/comedi/drivers/ni_labpc_isadma.c b/drivers/staging/comedi/drivers/ni_labpc_isadma.c index 2fb7e728049b..af13f4b37daa 100644 --- a/drivers/staging/comedi/drivers/ni_labpc_isadma.c +++ b/drivers/staging/comedi/drivers/ni_labpc_isadma.c @@ -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); - 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 */ devpriv->write_byte(dev, 0x1, DMATC_CLEAR_REG); |