Messages in this thread | | | Subject | Re: [PATCH 2/2] watchdog: rti: tweak min_hw_heartbeat_ms to match initial allowed window | From | Tero Kristo <> | Date | Thu, 25 Jun 2020 11:32:07 +0300 |
| |
On 24/06/2020 18:24, Jan Kiszka wrote: > On 24.06.20 13:45, Tero Kristo wrote: >> If the RTI watchdog has been started by someone (like bootloader) when >> the driver probes, we must adjust the initial ping timeout to match the >> currently running watchdog window to avoid generating watchdog reset. >> >> Signed-off-by: Tero Kristo <t-kristo@ti.com> >> --- >> drivers/watchdog/rti_wdt.c | 25 +++++++++++++++++++++++++ >> 1 file changed, 25 insertions(+) >> >> diff --git a/drivers/watchdog/rti_wdt.c b/drivers/watchdog/rti_wdt.c >> index d456dd72d99a..02ea2b2435f5 100644 >> --- a/drivers/watchdog/rti_wdt.c >> +++ b/drivers/watchdog/rti_wdt.c >> @@ -55,11 +55,13 @@ static int heartbeat; >> * @base - base io address of WD device >> * @freq - source clock frequency of WDT >> * @wdd - hold watchdog device as is in WDT core >> + * @min_hw_heartbeat_save - save of the min hw heartbeat value >> */ >> struct rti_wdt_device { >> void __iomem *base; >> unsigned long freq; >> struct watchdog_device wdd; >> + unsigned int min_hw_heartbeat_save; >> }; >> static int rti_wdt_start(struct watchdog_device *wdd) >> @@ -107,6 +109,11 @@ static int rti_wdt_ping(struct watchdog_device *wdd) >> /* put watchdog in active state */ >> writel_relaxed(WDKEY_SEQ1, wdt->base + RTIWDKEY); >> + if (wdt->min_hw_heartbeat_save) { >> + wdd->min_hw_heartbeat_ms = wdt->min_hw_heartbeat_save; >> + wdt->min_hw_heartbeat_save = 0; >> + } >> + >> return 0; >> } >> @@ -201,6 +208,24 @@ static int rti_wdt_probe(struct platform_device >> *pdev) >> goto err_iomap; >> } >> + if (readl(wdt->base + RTIDWDCTRL) == WDENABLE_KEY) { >> + u32 time_left; >> + u32 heartbeat; >> + >> + set_bit(WDOG_HW_RUNNING, &wdd->status); >> + time_left = rti_wdt_get_timeleft(wdd); >> + heartbeat = readl(wdt->base + RTIDWDPRLD); >> + heartbeat <<= WDT_PRELOAD_SHIFT; >> + heartbeat /= wdt->freq; >> + if (time_left < heartbeat / 2) >> + wdd->min_hw_heartbeat_ms = 0; >> + else >> + wdd->min_hw_heartbeat_ms = >> + (time_left - heartbeat / 2 + 1) * 1000; >> + >> + wdt->min_hw_heartbeat_save = 11 * heartbeat * 1000 / 20; >> + } >> + >> ret = watchdog_register_device(wdd); >> if (ret) { >> dev_err(dev, "cannot register watchdog device\n"); >> > > This assumes that the bootloader also programmed a 50% window, right? > The pending U-Boot patch will do that, but what if that may chance or > someone uses a different setup?
Yes, we assume 50%. I think based on the hw design, 50% is the only sane value to be used, otherwise you just shrink the open window too much and for no apparent reason.
-Tero -- Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
| |