On 08.11.24 22:15, A. Sverdlin wrote: > From: Alexander Sverdlin <[email protected]> > > If the RTI watchdog has been enabled in SPL, enabling it in U-Boot proper > fails because it can only be enabled once in HW and never stopped. This > however leads to a situation that wdt_cyclic() watchdog trigger is not > being started any longer and the WDT fires at some point.
Nothing against this change, just pointing out that, when a watchdog is supposed to monitor a complete boot, you normally don't want it to be triggered anymore before that boot is complete, neither from the kernel (watchdog.handle_boot_enabled=0) nor from U-Boot (CONFIG_WATCHDOG_AUTOSTART=n + script-based starting, or skip in in proper when started by SPL). Anything else always comes with the risk of running into a logically stuck boot that happily pets the watchdog until eternity - and you have to ask someone to manually reset your device. > > Allow for WDT re-start by not bailing out if the [previously] configured > period matches the one to be configured. > > Enabling in [A53] SPL has been tested on AM62x-based HW (where [A53] SPL is > responsible for loading R5 DM firmware and not this driver). > > Signed-off-by: Alexander Sverdlin <[email protected]> > --- > drivers/watchdog/rti_wdt.c | 13 +++++++------ > 1 file changed, 7 insertions(+), 6 deletions(-) > > diff --git a/drivers/watchdog/rti_wdt.c b/drivers/watchdog/rti_wdt.c > index 99168d0cad03..320c5ca19e0a 100644 > --- a/drivers/watchdog/rti_wdt.c > +++ b/drivers/watchdog/rti_wdt.c > @@ -131,18 +131,19 @@ static int rti_wdt_start(struct udevice *dev, u64 > timeout_ms, ulong flags) > u32 timer_margin; > int ret; > > - if (readl(priv->regs + RTIDWDCTRL) == WDENABLE_KEY) > + timer_margin = timeout_ms * priv->clk_hz / 1000; > + timer_margin >>= WDT_PRELOAD_SHIFT; > + if (timer_margin > WDT_PRELOAD_MAX) > + timer_margin = WDT_PRELOAD_MAX; > + > + if (readl(priv->regs + RTIDWDCTRL) == WDENABLE_KEY && > + readl(priv->regs + RTIDWDPRLD) != timer_margin) > return -EBUSY; > > ret = rti_wdt_load_fw(dev); > if (ret < 0) > return ret; > > - timer_margin = timeout_ms * priv->clk_hz / 1000; > - timer_margin >>= WDT_PRELOAD_SHIFT; > - if (timer_margin > WDT_PRELOAD_MAX) > - timer_margin = WDT_PRELOAD_MAX; > - > writel(timer_margin, priv->regs + RTIDWDPRLD); > writel(RTIWWDRX_NMI, priv->regs + RTIWWDRXCTRL); > writel(RTIWWDSIZE_50P, priv->regs + RTIWWDSIZECTRL); Reviewed-by: Jan Kiszka <[email protected]> Jan -- Siemens AG, Technology Linux Expert Center
