Commit 905a8321 authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
Browse files

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: default avatarH Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: default avatarIan Abbott <abbotti@mev.co.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent edf0f32b

drivers/staging/comedi/drivers/pcl818.c

+20 −25
Original line number Diff line number Diff line
@@ -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.

	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;
@@ -1065,13 +1058,15 @@ 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)) {

			if (!devpriv->ai_cmd_canceled) {

				/*

				* Wait for running dma transfer to end,

				* do cleanup in interrupt.

				*/

			devpriv->irq_was_now_closed = 1;

				devpriv->ai_cmd_canceled = 1;

				return 0;

			}

		}

		disable_dma(devpriv->dma);

	case INT_TYPE_AI1_INT:

	case INT_TYPE_AI3_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;

	}