From bed8d5381c8cf34fd7511cd02bb7e312ec83addf Mon Sep 17 00:00:00 2001
From: H Hartley Sweeten <hsweeten@visionengravers.com>
Date: Tue, 13 Jan 2015 10:16:21 -0700
Subject: [PATCH] staging: comedi: pcl818: introduce pcl818_isadma_disable()
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>
---
drivers/staging/comedi/drivers/pcl818.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/drivers/staging/comedi/drivers/pcl818.c b/drivers/staging/comedi/drivers/pcl818.c
index 4f5f4e94ae0f..a1279c24afb9 100644
--- a/drivers/staging/comedi/drivers/pcl818.c
+++ b/drivers/staging/comedi/drivers/pcl818.c
@@ -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);
--
2.34.1