[PATCH v5] Staging: comedi: convert while loop to timeout in ni_mio_common.c
Ian Abbott
abbotti at mev.co.uk
Wed Jan 15 10:38:04 UTC 2014
On 2014-01-15 05:15, Chase Southwood wrote:
> This patch for ni_mio_common.c changes out a while loop for a timeout,
> which is preferred.
>
> Signed-off-by: Chase Southwood <chase.southwood at yahoo.com>
> ---
>
> All right, I think this guy's ready to go now! Thanks for all the help!
> Chase
>
> 2: Changed from simple clean-up to swapping a timeout in for a while loop.
>
> 3: Removed extra counter variable, and added error checking.
>
> 4: No longer using counter variable, using jiffies instead.
>
> 5: udelay for 10u, instead of 1u.
>
> drivers/staging/comedi/drivers/ni_mio_common.c | 11 ++++++++++-
> 1 file changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/staging/comedi/drivers/ni_mio_common.c b/drivers/staging/comedi/drivers/ni_mio_common.c
> index 457b884..07e9777 100644
> --- a/drivers/staging/comedi/drivers/ni_mio_common.c
> +++ b/drivers/staging/comedi/drivers/ni_mio_common.c
> @@ -687,12 +687,21 @@ static void ni_clear_ai_fifo(struct comedi_device *dev)
> {
> const struct ni_board_struct *board = comedi_board(dev);
> struct ni_private *devpriv = dev->private;
> + unsigned long timeout;
>
> if (board->reg_type == ni_reg_6143) {
> /* Flush the 6143 data FIFO */
> ni_writel(0x10, AIFIFO_Control_6143); /* Flush fifo */
> ni_writel(0x00, AIFIFO_Control_6143); /* Flush fifo */
> - while (ni_readl(AIFIFO_Status_6143) & 0x10) ; /* Wait for complete */
> + /* Wait for complete */
> + timeout = jiffies + msec_to_jiffies(500);
> + while (ni_readl(AIFIFO_Status_6143) & 0x10) {
> + if (time_after(jiffies, timeout)) {
> + comedi_error(dev, "FIFO flush timeout.");
> + break;
> + }
> + udelay(10);
I preferred the earlier udelay(1) from your PATCH v4, but I think it's
even better to replace it with:
cpu_relax();
You might also need:
#include <asm/processor.h>
to define cpu_relax().
> + }
> } else {
> devpriv->stc_writew(dev, 1, ADC_FIFO_Clear);
> if (board->reg_type == ni_reg_625x) {
>
--
-=( Ian Abbott @ MEV Ltd. E-mail: <abbotti at mev.co.uk> )=-
-=( Tel: +44 (0)161 477 1898 FAX: +44 (0)161 718 3587 )=-
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