| Message ID | 20191122132246.8473-1-christophe.roullier@st.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | [v3,1/1] drivers: watchdog: stm32_iwdg: set WDOG_HW_RUNNING at probe | expand |
On Fri, Nov 22, 2019 at 02:22:46PM +0100, Christophe Roullier wrote: > If the watchdog hardware is already enabled during the boot process, > when the Linux watchdog driver loads, it should start/reset the watchdog > and tell the watchdog framework. As a result, ping can be generated from > the watchdog framework (if CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED is set), > until the userspace watchdog daemon takes over control > > Fixes:4332d113c66a ("watchdog: Add STM32 IWDG driver") > > Signed-off-by: Christophe Roullier <christophe.roullier@st.com> Reviewed-by: Guenter Roeck <linux@roeck-us.net> > --- > Changes since v2: > According to Guenter > removed intermediate variable > > I've tested some config and it is working as expected: > Watchdog enable in Uboot + HANDLE_BOOT_ENABLE is not set + daemon watchdog in userland ON ==> No reset IWDG2 > Watchdog enable in Uboot + HANDLE_BOOT_ENABLE is not set ==> Reset IWDG2 > Watchdog enable in Uboot + HANDLE_BOOT_ENABLE=y ==> No reset IWDG2 > Watchdog enable in Uboot + HANDLE_BOOT_ENABLE=y + daemon watchdog in userland ON puis OFF ==> Reset IWDG2 > Watchdog disable in Uboot + HANDLE_BOOT_ENABLE is not set ==> No reset IWDG2 > Watchdog disable in Uboot + HANDLE_BOOT_ENABLE=y ==> No reset IWDG2 > Watchdog disable in Uboot + HANDLE_BOOT_ENABLE=y + daemon watchdog in userland ON ==> No reset IWDG2 > Watchdog disable in Uboot + HANDLE_BOOT_ENABLE=y + daemon watchdog in userland ON puis OFF ==> Reset IWDG2 > > Thanks, > Christophe > > drivers/watchdog/stm32_iwdg.c | 18 ++++++++++++++++++ > 1 file changed, 18 insertions(+) > > diff --git a/drivers/watchdog/stm32_iwdg.c b/drivers/watchdog/stm32_iwdg.c > index a3a329011a06..25188d6bbe15 100644 > --- a/drivers/watchdog/stm32_iwdg.c > +++ b/drivers/watchdog/stm32_iwdg.c > @@ -262,6 +262,24 @@ static int stm32_iwdg_probe(struct platform_device *pdev) > watchdog_set_nowayout(wdd, WATCHDOG_NOWAYOUT); > watchdog_init_timeout(wdd, 0, dev); > > + /* > + * In case of CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED is set > + * (Means U-Boot/bootloaders leaves the watchdog running) > + * When we get here we should make a decision to prevent > + * any side effects before user space daemon will take care of it. > + * The best option, taking into consideration that there is no > + * way to read values back from hardware, is to enforce watchdog > + * being run with deterministic values. > + */ > + if (IS_ENABLED(CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED)) { > + ret = stm32_iwdg_start(wdd); > + if (ret) > + return ret; > + > + /* Make sure the watchdog is serviced */ > + set_bit(WDOG_HW_RUNNING, &wdd->status); > + } > + > ret = devm_watchdog_register_device(dev, wdd); > if (ret) > return ret; > -- > 2.17.1 >
diff --git a/drivers/watchdog/stm32_iwdg.c b/drivers/watchdog/stm32_iwdg.c index a3a329011a06..25188d6bbe15 100644 --- a/drivers/watchdog/stm32_iwdg.c +++ b/drivers/watchdog/stm32_iwdg.c @@ -262,6 +262,24 @@ static int stm32_iwdg_probe(struct platform_device *pdev) watchdog_set_nowayout(wdd, WATCHDOG_NOWAYOUT); watchdog_init_timeout(wdd, 0, dev); + /* + * In case of CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED is set + * (Means U-Boot/bootloaders leaves the watchdog running) + * When we get here we should make a decision to prevent + * any side effects before user space daemon will take care of it. + * The best option, taking into consideration that there is no + * way to read values back from hardware, is to enforce watchdog + * being run with deterministic values. + */ + if (IS_ENABLED(CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED)) { + ret = stm32_iwdg_start(wdd); + if (ret) + return ret; + + /* Make sure the watchdog is serviced */ + set_bit(WDOG_HW_RUNNING, &wdd->status); + } + ret = devm_watchdog_register_device(dev, wdd); if (ret) return ret;
If the watchdog hardware is already enabled during the boot process, when the Linux watchdog driver loads, it should start/reset the watchdog and tell the watchdog framework. As a result, ping can be generated from the watchdog framework (if CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED is set), until the userspace watchdog daemon takes over control Fixes:4332d113c66a ("watchdog: Add STM32 IWDG driver") Signed-off-by: Christophe Roullier <christophe.roullier@st.com> --- Changes since v2: According to Guenter removed intermediate variable I've tested some config and it is working as expected: Watchdog enable in Uboot + HANDLE_BOOT_ENABLE is not set + daemon watchdog in userland ON ==> No reset IWDG2 Watchdog enable in Uboot + HANDLE_BOOT_ENABLE is not set ==> Reset IWDG2 Watchdog enable in Uboot + HANDLE_BOOT_ENABLE=y ==> No reset IWDG2 Watchdog enable in Uboot + HANDLE_BOOT_ENABLE=y + daemon watchdog in userland ON puis OFF ==> Reset IWDG2 Watchdog disable in Uboot + HANDLE_BOOT_ENABLE is not set ==> No reset IWDG2 Watchdog disable in Uboot + HANDLE_BOOT_ENABLE=y ==> No reset IWDG2 Watchdog disable in Uboot + HANDLE_BOOT_ENABLE=y + daemon watchdog in userland ON ==> No reset IWDG2 Watchdog disable in Uboot + HANDLE_BOOT_ENABLE=y + daemon watchdog in userland ON puis OFF ==> Reset IWDG2 Thanks, Christophe drivers/watchdog/stm32_iwdg.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+)