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staging: comedi: pcl818: introduce pcl818_isadma_disable()

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According to Documentation/DMA-ISA-LPC.txt, the DMA lock needs to be
claimed before using any of the ISA DMA routines. Introduce a helper
function to disable the ISA DMA controller and add the necessary
locking calls.

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 10:16:21 -07:00 committed by Greg Kroah-Hartman
parent 9cf2765f5e
commit bed8d5381c
1 changed files with 12 additions and 3 deletions
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15
drivers/staging/comedi/drivers/pcl818.c
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@ -342,6 +342,15 @@ static void pcl818_isadma_program(unsigned int dma_chan,
release_dma_lock(flags);
}
static void pcl818_isadma_disable(unsigned int dma_chan)
{
unsigned long flags;
flags = claim_dma_lock();
disable_dma(dma_chan);
release_dma_lock(flags);
}
static void pcl818_start_pacer(struct comedi_device *dev, bool load_counters)
{
struct pcl818_private *devpriv = dev->private;
@ -364,7 +373,7 @@ static void pcl818_ai_setup_dma(struct comedi_device *dev,
struct pcl818_dma_desc *dma = &devpriv->dma_desc[0];
struct comedi_cmd *cmd = &s->async->cmd;
disable_dma(devpriv->dma); /* disable dma */
pcl818_isadma_disable(devpriv->dma);
if (cmd->stop_src == TRIG_COUNT) {
dma->size = cmd->stop_arg * comedi_bytes_per_scan(s);
devpriv->dma_runs_to_end = dma->size / devpriv->hwdmasize;
@ -388,7 +397,7 @@ static void pcl818_ai_setup_next_dma(struct comedi_device *dev,
struct comedi_cmd *cmd = &s->async->cmd;
struct pcl818_dma_desc *dma;
disable_dma(devpriv->dma);
pcl818_isadma_disable(devpriv->dma);
devpriv->cur_dma = 1 - devpriv->cur_dma;
if (devpriv->dma_runs_to_end > -1 || cmd->stop_src == TRIG_NONE) {
/* switch dma bufs */
@ -879,7 +888,7 @@ static int pcl818_ai_cancel(struct comedi_device *dev,
return 0;
}
}
disable_dma(devpriv->dma);
pcl818_isadma_disable(devpriv->dma);
}
outb(PCL818_CTRL_DISABLE_TRIG, dev->iobase + PCL818_CTRL_REG);