On Wed, Jan 10, 2018 at 12:13:22PM +0000, André Draszik wrote:
> This patch uses the new flag WDOG_HW_RUNNING in driver.
> According to the definition of this flag, it should be set
> if the watchdog hardware is enabled/running during boot
> before being opened here, e.g. due to a boot loader
> configuring the watchdog.
>
> Given the watchdog driver core doesn't know what timeout was
> originally set by whoever started the watchdog (boot loader),
> we make sure to update the timeout in the hardware according
> to what the watchdog core thinks it is.
>
> Signed-off-by: André Draszik <git@xxxxxxxxxx>
> Cc: Wim Van Sebroeck <wim@xxxxxxxxx>
> Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
> Cc: linux-watchdog@xxxxxxxxxxxxxxx
> Cc: John Crispin <john@xxxxxxxxxxx>
> ---
> drivers/watchdog/mt7621_wdt.c | 16 ++++++++++++++++
> 1 file changed, 16 insertions(+)
>
> diff --git a/drivers/watchdog/mt7621_wdt.c b/drivers/watchdog/mt7621_wdt.c
> index db38f8017218..0eabea2d88a2 100644
> --- a/drivers/watchdog/mt7621_wdt.c
> +++ b/drivers/watchdog/mt7621_wdt.c
> @@ -105,6 +105,11 @@ static int mt7621_wdt_bootcause(void)
> return 0;
> }
>
> +static int mt7621_wdt_is_running(struct watchdog_device *w)
> +{
> + return !!(rt_wdt_r32(TIMER_REG_TMR1CTL) & TMR1CTL_ENABLE);
> +}
> +
> static const struct watchdog_info mt7621_wdt_info = {
> .identity = "Mediatek Watchdog",
> .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
> @@ -144,6 +149,17 @@ static int mt7621_wdt_probe(struct platform_device *pdev)
> watchdog_init_timeout(&mt7621_wdt_dev, mt7621_wdt_dev.max_timeout,
> &pdev->dev);
> watchdog_set_nowayout(&mt7621_wdt_dev, nowayout);
> + if (mt7621_wdt_is_running(&mt7621_wdt_dev)) {
> + /* Make sure to apply timeout from wathdog_core, taking
watchdog core
> + the prescaler of this driver here into account (the
> + boot loader might be using a different prescaler).
> + To avoid spurious resets because of different scaling,
> + we first disable the watchdog, set the new prescaler
> + and timeout, and then re-enable the watchdog. */
Please use proper multi-line comments.
> + mt7621_wdt_stop(&mt7621_wdt_dev);
> + mt7621_wdt_start(&mt7621_wdt_dev);
> + set_bit(WDOG_HW_RUNNING, &mt7621_wdt_dev.status);
> + }
>
> ret = watchdog_register_device(&mt7621_wdt_dev);
>
> --
> 2.15.1
>
> --
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