From 905a83211825d11716192043527ed7f84b0572a7 Mon Sep 17 00:00:00 2001 From: H Hartley Sweeten Date: Tue, 4 Mar 2014 11:29:45 -0700 Subject: [PATCH] staging: comedi: pcl818: fix (*cancel) when cmd->stop_src == TRIG_NONE 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 Reviewed-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- 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 c820df2aac45..6c91a7b424d8 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; } -- 2.30.2