Hello,
On Wed, Apr 22, 2015 at 02:11:42PM +0300, Timo Kokkonen wrote:
> Use the new watchdog core extensions to let watchdog core take over
> boot time watchdog behavior. The difference is that early-timeout-sec
> device tree property becomes available for this driver and a running
> watchdog is not stopped unless the core decides to stop it.
>
> Omap watchdog is running by default in the boot up but bootloader
> might have stopped it. Therefore we fill the WDOG_HW_RUNNING_AT_BOOT
> bit depending on the actual watchdog state so that the watchdog core
> can act properly.
>
> Signed-off-by: Timo Kokkonen <timo.kokkonen@xxxxxxxxxx>
> ---
> drivers/watchdog/omap_wdt.c | 28 +++++++++++++++++++++++++++-
> 1 file changed, 27 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/watchdog/omap_wdt.c b/drivers/watchdog/omap_wdt.c
> index bbaf39a..7164f2e 100644
> --- a/drivers/watchdog/omap_wdt.c
> +++ b/drivers/watchdog/omap_wdt.c
> @@ -78,6 +78,13 @@ static void omap_wdt_reload(struct omap_wdt_dev *wdev)
> /* reloaded WCRR from WLDR */
> }
>
> +static int omap_wdt_is_running(struct omap_wdt_dev *wdev)
> +{
> + void __iomem *base = wdev->base;
> +
> + return readl_relaxed(base + OMAP_WATCHDOG_SPR) == 0x4444;
> +}
This isn't reliable. The sequence needed to enable the watchdog is
writel(0xbbbb, base + OMAP_WATCHDOG_SPR);
writel(0x4444, base + OMAP_WATCHDOG_SPR);
The sequence to stop is:
writel(0xaaaa, base + OMAP_WATCHDOG_SPR);
writel(0x5555, base + OMAP_WATCHDOG_SPR);
But:
barebox@TI AM335x BeagleBone black:/ md 0x44e35048+4
44e35048: 00005555 UU..
barebox@TI AM335x BeagleBone black:/ mw 0x44e35048 0x4444
barebox@TI AM335x BeagleBone black:/ md 0x44e35048+4
44e35048: 00004444 DD..
So the register contains 0x4444 but the timer doesn't run. So at best
testing for 0x4444 is a good heuristic.
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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