lkml.org 
[lkml]   [2019]   [Nov]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH v2 1/1] drivers: watchdog: stm32_iwdg: set WDOG_HW_RUNNING at probe
From
Date
On 11/22/19 12:24 AM, 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>
> ---
> Changes since v1:
> According to Guenter
> I follow the guidance from intel-mid_wdt.c
> and I added test to check if CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED is set
> because we need to be flexible (depends on customer config, but watchdog
> not always start by bootloader (Uboot, ..))
> 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 | 21 +++++++++++++++++++++
> 1 file changed, 21 insertions(+)
>
> diff --git a/drivers/watchdog/stm32_iwdg.c b/drivers/watchdog/stm32_iwdg.c
> index a3a329011a06..7f454a6e17ba 100644
> --- a/drivers/watchdog/stm32_iwdg.c
> +++ b/drivers/watchdog/stm32_iwdg.c
> @@ -50,6 +50,9 @@
> #define TIMEOUT_US 100000
> #define SLEEP_US 1000
>
> +static bool handle_boot_enabled =
> + IS_ENABLED(CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED);
> +
> struct stm32_iwdg_data {
> bool has_pclk;
> u32 max_prescaler;
> @@ -262,6 +265,24 @@ 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 (handle_boot_enabled) {

You don't need that variable. Just use
if (IS_ENABLED(CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED)) {
directly.

> + 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;
>

\
 
 \ /
  Last update: 2019-11-22 12:20    [from the cache]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and my Meterkast|Read the blog