When using DMA, the async command (*cancel) operation is delayed until the
current DMA transfer is complete. When the DMA transfer finishes the interrupt
routine detects this and calls the (*cancel) again which should then cancel the
async command.
The current logic does not work when cmd->stop_src == TRIG_NONE. In this case
the (*cancel) function keeps delaying the cancel. The actual DMA does stop
because the DMA handler is not called to setup the next transfer but the
(*cancel) code is never executed.
Rename the 'irq_was_now_closed' flag in the private data to 'ai_cmd_canceled'
to clarify what it is.
Only set the flag in the (*cancel) when a DMA transfer is running and the
async command has not already been canceled. The interrupt routine then does
not need all the extra checks.
Signed-off-by: H Hartley Sweeten <hswee...@visionengravers.com>
Cc: Ian Abbott <abbo...@mev.co.uk>
Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
drivers/staging/comedi/drivers/pcl818.c | 45 +++++++++++++++------------------
1 file changed, 20 insertions(+), 25 deletions(-)
diff --git a/drivers/staging/comedi/drivers/pcl818.c
b/drivers/staging/comedi/drivers/pcl818.c
index c820df2..6c91a7b 100644
--- a/drivers/staging/comedi/drivers/pcl818.c
+++ b/drivers/staging/comedi/drivers/pcl818.c
@@ -332,7 +332,7 @@ struct pcl818_private {
unsigned int divisor2;
unsigned int usefifo:1;
unsigned int ai_cmd_running:1;
- unsigned int irq_was_now_closed:1;
+ unsigned int ai_cmd_canceled:1;
};
static const unsigned int muxonechan[] = { 0x00, 0x11, 0x22, 0x33, 0x44, 0x55,
0x66, 0x77, /* used for gain list programming */
@@ -731,29 +731,22 @@ static irqreturn_t interrupt_pcl818(int irq, void *d)
struct comedi_device *dev = d;
struct pcl818_private *devpriv = dev->private;
struct comedi_subdevice *s = dev->read_subdev;
- struct comedi_cmd *cmd = &s->async->cmd;
if (!dev->attached) {
comedi_error(dev, "premature interrupt");
return IRQ_HANDLED;
}
- if (devpriv->ai_cmd_running && devpriv->irq_was_now_closed) {
- if ((cmd->stop_src == TRIG_NONE ||
- (cmd->stop_src == TRIG_COUNT && devpriv->ai_act_scan > 0))
&&
- (devpriv->ai_mode == INT_TYPE_AI1_DMA ||
- devpriv->ai_mode == INT_TYPE_AI3_DMA)) {
- /* The cleanup from ai_cancel() has been delayed
- until now because the card doesn't seem to like
- being reprogrammed while a DMA transfer is in
- progress.
- */
- devpriv->ai_act_scan = 0;
- s->cancel(dev, s);
- }
-
+ if (devpriv->ai_cmd_canceled) {
+ /*
+ * The cleanup from ai_cancel() has been delayed
+ * until now because the card doesn't seem to like
+ * being reprogrammed while a DMA transfer is in
+ * progress.
+ */
+ devpriv->ai_act_scan = 0;
+ s->cancel(dev, s);
outb(0, dev->iobase + PCL818_CLRINT); /* clear INT request */
-
return IRQ_HANDLED;
}
@@ -820,7 +813,7 @@ static int pcl818_ai_cmd_mode(int mode, struct
comedi_device *dev,
devpriv->ai_act_scan = cmd->stop_arg;
devpriv->ai_act_chan = 0;
devpriv->ai_cmd_running = 1;
- devpriv->irq_was_now_closed = 0;
+ devpriv->ai_cmd_canceled = 0;
devpriv->act_chanlist_pos = 0;
devpriv->dma_runs_to_end = 0;
@@ -1065,12 +1058,14 @@ static int pcl818_ai_cancel(struct comedi_device *dev,
case INT_TYPE_AI3_DMA:
if (cmd->stop_src == TRIG_NONE ||
(cmd->stop_src == TRIG_COUNT && devpriv->ai_act_scan > 0)) {
- /*
- * Wait for running dma transfer to end,
- * do cleanup in interrupt.
- */
- devpriv->irq_was_now_closed = 1;
- return 0;
+ if (!devpriv->ai_cmd_canceled) {
+ /*
+ * Wait for running dma transfer to end,
+ * do cleanup in interrupt.
+ */
+ devpriv->ai_cmd_canceled = 1;
+ return 0;
+ }
}
disable_dma(devpriv->dma);
case INT_TYPE_AI1_INT:
@@ -1092,7 +1087,7 @@ static int pcl818_ai_cancel(struct comedi_device *dev,
}
devpriv->ai_cmd_running = 0;
devpriv->ai_mode = 0;
- devpriv->irq_was_now_closed = 0;
+ devpriv->ai_cmd_canceled = 0;
break;
}
--
1.8.5.2
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