On 9/8/20 2:56 AM, Wolfram Sang wrote:
> Support an already running watchdog by checking its enable bit and set
> up the status accordingly before registering the device.
>
> Signed-off-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>
Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> ---
>
> This is the same patch as V2 sent out nearly one year ago. There was one
> issue when probe() failed and the clocks were disabled, so the WDT
> wouldn't fire despite the FW set it up before. We fixed this at clk
> driver level and all the commits are upstream now. I tested this on a
> Renesas Salvator-XS board (R-Car M3N) with all combinations of
> HANDLE_BOOT_ENABLED, open_timeout values and injected failures I could
> think of. This patch is now good to go IMO.
>
> drivers/watchdog/renesas_wdt.c | 12 ++++++++++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/watchdog/renesas_wdt.c b/drivers/watchdog/renesas_wdt.c
> index 00662a8e039c..47fce4de0110 100644
> --- a/drivers/watchdog/renesas_wdt.c
> +++ b/drivers/watchdog/renesas_wdt.c
> @@ -194,6 +194,7 @@ static int rwdt_probe(struct platform_device *pdev)
> struct clk *clk;
> unsigned long clks_per_sec;
> int ret, i;
> + u8 csra;
>
> if (rwdt_blacklisted(dev))
> return -ENODEV;
> @@ -213,8 +214,8 @@ static int rwdt_probe(struct platform_device *pdev)
> pm_runtime_enable(dev);
> pm_runtime_get_sync(dev);
> priv->clk_rate = clk_get_rate(clk);
> - priv->wdev.bootstatus = (readb_relaxed(priv->base + RWTCSRA) &
> - RWTCSRA_WOVF) ? WDIOF_CARDRESET : 0;
> + csra = readb_relaxed(priv->base + RWTCSRA);
> + priv->wdev.bootstatus = csra & RWTCSRA_WOVF ? WDIOF_CARDRESET : 0;
> pm_runtime_put(dev);
>
> if (!priv->clk_rate) {
> @@ -252,6 +253,13 @@ static int rwdt_probe(struct platform_device *pdev)
> /* This overrides the default timeout only if DT configuration was found */
> watchdog_init_timeout(&priv->wdev, 0, dev);
>
> + /* Check if FW enabled the watchdog */
> + if (csra & RWTCSRA_TME) {
> + /* Ensure properly initialized dividers */
> + rwdt_start(&priv->wdev);
> + set_bit(WDOG_HW_RUNNING, &priv->wdev.status);
> + }
> +
> ret = watchdog_register_device(&priv->wdev);
> if (ret < 0)
> goto out_pm_disable;
>
