Hi, 03.05.2015 21:56, Uwe Kleine-König wrote:
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.
Yeah.. I don't think we can get any better than that. Unless we start checking the counter register and see whether it really counts or not, and I think that's a bit overkill.. So I'd say we should be safe when assuming bootloader is doing things correctly. Although, we could add a comment to the code that the test may not be 100% reliable in case the start sequence have not been issued properly.
Thanks for pointing this out! -Timo -- To unsubscribe from this list: send the line "unsubscribe linux-watchdog" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
