On Tue, Sep 26, 2017 at 08:11:22AM +0200, Oleksij Rempel wrote:
> The only way of stopping the watchdog is by resetting it.
> Add the watchdog op for stopping the device and reset if
> a reset line is provided.
>
> At same time WDOG_HW_RUNNING should be remove from dw_wdt_start.
> As commented by Guenter Roeck:
> dw_wdt sets WDOG_HW_RUNNING in its open function. Result is
> that the kref_get() in watchdog_open() won't be executed. But then
> kref_put() in close will be called since the watchdog now does stop.
> This causes the imbalance.
>
> Signed-off-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>
> Cc: Wim Van Sebroeck <wim@xxxxxxxxx>
> Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
> Cc: linux-watchdog@xxxxxxxxxxxxxxx
Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> ---
>
> changes v4:
> - remove WDOG_HW_RUNNING from dw_wdt_start.
>
> changes v3:
> - don't return error if rst is not present and set WDOG_HW_RUNNING bit
> to notify watchdog core.
>
> changes v2:
> - test if dw_wdt->rst is NULL instead of IS_ERR
>
> drivers/watchdog/dw_wdt.c | 18 ++++++++++++++++--
> 1 file changed, 16 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c
> index 36be987ff9ef..c2f4ff516230 100644
> --- a/drivers/watchdog/dw_wdt.c
> +++ b/drivers/watchdog/dw_wdt.c
> @@ -127,14 +127,27 @@ static int dw_wdt_start(struct watchdog_device *wdd)
>
> dw_wdt_set_timeout(wdd, wdd->timeout);
>
> - set_bit(WDOG_HW_RUNNING, &wdd->status);
> -
> writel(WDOG_CONTROL_REG_WDT_EN_MASK,
> dw_wdt->regs + WDOG_CONTROL_REG_OFFSET);
>
> return 0;
> }
>
> +static int dw_wdt_stop(struct watchdog_device *wdd)
> +{
> + struct dw_wdt *dw_wdt = to_dw_wdt(wdd);
> +
> + if (!dw_wdt->rst) {
> + set_bit(WDOG_HW_RUNNING, &wdd->status);
> + return 0;
> + }
> +
> + reset_control_assert(dw_wdt->rst);
> + reset_control_deassert(dw_wdt->rst);
> +
> + return 0;
> +}
> +
> static int dw_wdt_restart(struct watchdog_device *wdd,
> unsigned long action, void *data)
> {
> @@ -173,6 +186,7 @@ static const struct watchdog_info dw_wdt_ident = {
> static const struct watchdog_ops dw_wdt_ops = {
> .owner = THIS_MODULE,
> .start = dw_wdt_start,
> + .stop = dw_wdt_stop,
> .ping = dw_wdt_ping,
> .set_timeout = dw_wdt_set_timeout,
> .get_timeleft = dw_wdt_get_timeleft,
> --
> 2.11.0
>
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