[PATCH 21/22] staging: comedi: adv_pci1710: handle events and clear interrupt in common code

[Ian Abbott]

On 2014-04-24 00:07, H Hartley Sweeten wrote:
> The helper functions that handle reading the analog input samples for
> the interrupt function both call cfc_handle_events() and clear the
> interrupt request at various times.
>
> Move this to the main interrupt handler to make sure the events are
> posted and the interrupt request is cleared.
>
> Signed-off-by: H Hartley Sweeten <hsweeten at visionengravers.com>
> Cc: Ian Abbott <abbotti at mev.co.uk>
> Cc: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
> ---
>   drivers/staging/comedi/drivers/adv_pci1710.c | 22 ++++------------------
>   1 file changed, 4 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/staging/comedi/drivers/adv_pci1710.c b/drivers/staging/comedi/drivers/adv_pci1710.c
> index 353b832..56186f0 100644
> --- a/drivers/staging/comedi/drivers/adv_pci1710.c
> +++ b/drivers/staging/comedi/drivers/adv_pci1710.c
> @@ -752,19 +752,15 @@ static void pci1710_handle_every_sample(struct comedi_device *dev,
>   	if (m & Status_FE) {
>   		dev_dbg(dev->class_dev, "A/D FIFO empty (%4x)\n", m);
>   		s->async->events |= COMEDI_CB_EOA | COMEDI_CB_ERROR;
> -		cfc_handle_events(dev, s);
>   		return;
>   	}
>   	if (m & Status_FF) {
>   		dev_dbg(dev->class_dev,
>   			"A/D FIFO Full status (Fatal Error!) (%4x)\n", m);
>   		s->async->events |= COMEDI_CB_EOA | COMEDI_CB_ERROR;
> -		cfc_handle_events(dev, s);
>   		return;
>   	}
>
> -	outb(0, dev->iobase + PCI171x_CLRINT);	/*  clear our INT request */
> -
>   	for (; !(inw(dev->iobase + PCI171x_STATUS) & Status_FE);) {
>   #ifdef PCI171x_PARANOIDCHECK
>   		sampl = inw(dev->iobase + PCI171x_AD_DATA);
> @@ -780,7 +776,6 @@ static void pci1710_handle_every_sample(struct comedi_device *dev,
>   				     12);
>   				s->async->events |=
>   				    COMEDI_CB_EOA | COMEDI_CB_ERROR;
> -				cfc_handle_events(dev, s);
>   				return;
>   			}
>   		comedi_buf_put(s->async, sampl & 0x0fff);
> @@ -793,22 +788,16 @@ static void pci1710_handle_every_sample(struct comedi_device *dev,
>   		if (s->async->cur_chan >= cmd->chanlist_len)
>   			s->async->cur_chan = 0;
>
> -
>   		if (s->async->cur_chan == 0) {	/*  one scan done */
>   			devpriv->ai_act_scan++;
>   			if (cmd->stop_src == TRIG_COUNT &&
>   			    devpriv->ai_act_scan >= cmd->stop_arg) {
>   				/*  all data sampled */
>   				s->async->events |= COMEDI_CB_EOA;
> -				cfc_handle_events(dev, s);
>   				return;
>   			}
>   		}
>   	}
> -
> -	outb(0, dev->iobase + PCI171x_CLRINT);	/*  clear our INT request */
> -
> -	cfc_handle_events(dev, s);
>   }
>
>   /*
> @@ -839,7 +828,6 @@ static int move_block_from_fifo(struct comedi_device *dev,
>   					sampl);
>   				s->async->events |=
>   				    COMEDI_CB_EOA | COMEDI_CB_ERROR;
> -				cfc_handle_events(dev, s);
>   				return 1;
>   			}
>   		comedi_buf_put(s->async, sampl & 0x0fff);
> @@ -869,14 +857,12 @@ static void pci1710_handle_fifo(struct comedi_device *dev,
>   	if (!(m & Status_FH)) {
>   		dev_dbg(dev->class_dev, "A/D FIFO not half full! (%4x)\n", m);
>   		s->async->events |= COMEDI_CB_EOA | COMEDI_CB_ERROR;
> -		cfc_handle_events(dev, s);
>   		return;
>   	}
>   	if (m & Status_FF) {
>   		dev_dbg(dev->class_dev,
>   			"A/D FIFO Full status (Fatal Error!) (%4x)\n", m);
>   		s->async->events |= COMEDI_CB_EOA | COMEDI_CB_ERROR;
> -		cfc_handle_events(dev, s);
>   		return;
>   	}
>
> @@ -897,12 +883,8 @@ static void pci1710_handle_fifo(struct comedi_device *dev,
>   	    devpriv->ai_act_scan >= cmd->stop_arg) {
>   		/* all data sampled */
>   		s->async->events |= COMEDI_CB_EOA;
> -		cfc_handle_events(dev, s);
>   		return;
>   	}
> -	outb(0, dev->iobase + PCI171x_CLRINT);	/*  clear our INT request */
> -
> -	cfc_handle_events(dev, s);
>   }
>
>   /*
> @@ -945,6 +927,10 @@ static irqreturn_t interrupt_service_pci1710(int irq, void *d)
>   	else
>   		pci1710_handle_fifo(dev, s);
>
> +	cfc_handle_events(dev, s);
> +
> +	outb(0, dev->iobase + PCI171x_CLRINT);
> +
>   	return IRQ_HANDLED;
>   }
>
>

It would be better to clear the interrupt _before_ calling 
pci1710_handle_every_sample() or pci1710_handle_fifo() in case new data 
arrives (and reasserts the interrupt) just after you've read the old data.

-- 
-=( Ian Abbott @ MEV Ltd.    E-mail: <abbotti at mev.co.uk>        )=-
-=( Tel: +44 (0)161 477 1898   FAX: +44 (0)161 718 3587         )=-