When setting up the DMA for 'read' streaming acquisition command, grab
the MITE channel spinlock before preparing and arming the DMA.
Change inspired by ni_ai_setup_MITE_dma() in ni_mio_common.c.
Signed-off-by: Ian Abbott <abbotti@xxxxxxxxx>
---
drivers/staging/comedi/drivers/ni_pcidio.c | 15 ++++++++++-----
1 files changed, 10 insertions(+), 5 deletions(-)
diff --git a/drivers/staging/comedi/drivers/ni_pcidio.c b/drivers/staging/comedi/drivers/ni_pcidio.c
index c9e5f2b..5145bf1 100644
--- a/drivers/staging/comedi/drivers/ni_pcidio.c
+++ b/drivers/staging/comedi/drivers/ni_pcidio.c
@@ -436,6 +436,7 @@ static int ni_pcidio_request_di_mite_channel(struct comedi_device *dev)
comedi_error(dev, "failed to reserve mite dma channel.");
return -EBUSY;
}
+ devpriv->di_mite_chan->dir = COMEDI_INPUT;
writeb(primary_DMAChannel_bits(devpriv->di_mite_chan->channel) |
secondary_DMAChannel_bits(devpriv->di_mite_chan->channel),
devpriv->mite->daq_io_addr + DMA_Line_Control_Group1);
@@ -1005,20 +1006,24 @@ static int ni_pcidio_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
static int setup_mite_dma(struct comedi_device *dev, struct comedi_subdevice *s)
{
int retval;
+ unsigned long flags;
retval = ni_pcidio_request_di_mite_channel(dev);
if (retval)
return retval;
- devpriv->di_mite_chan->dir = COMEDI_INPUT;
-
/* write alloc the entire buffer */
comedi_buf_write_alloc(s->async, s->async->prealloc_bufsz);
- mite_prep_dma(devpriv->di_mite_chan, 32, 32);
+ spin_lock_irqsave(&devpriv->mite_channel_lock, flags);
+ if (devpriv->di_mite_chan) {
+ mite_prep_dma(devpriv->di_mite_chan, 32, 32);
+ mite_dma_arm(devpriv->di_mite_chan);
+ } else
+ retval = -EIO;
+ spin_unlock_irqrestore(&devpriv->mite_channel_lock, flags);
- mite_dma_arm(devpriv->di_mite_chan);
- return 0;
+ return retval;
}
static int ni_pcidio_inttrig(struct comedi_device *dev,
--
1.7.8.2
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