watchdog: s3c2410: Let kernel kick watchdog

When "tmr_atboot" module param is set, the watchdog is started in
driver's probe. In that case, also set WDOG_HW_RUNNING bit to let
watchdog core driver know it's running. This way watchdog core can kick
the watchdog for us (if CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED option is
enabled), until user space takes control.

WDOG_HW_RUNNING bit must be set before registering the watchdog. So the
"tmr_atboot" handling code is moved before watchdog registration, to
avoid performing the same check twice. This is also logical because
WDOG_HW_RUNNING bit makes WDT core expect actually running watchdog.

Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20211107202943.8859-5-semen.protsenko@linaro.org
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

diff --git a/drivers/watchdog/s3c2410_wdt.c b/drivers/watchdog/s3c2410_wdt.c
index 00421cf..0845c05 100644 (file)
--- a/drivers/watchdog/s3c2410_wdt.c
+++ b/drivers/watchdog/s3c2410_wdt.c
@@ -604,6 +604,21 @@ static int s3c2410wdt_probe(struct platform_device *pdev)
        wdt->wdt_device.bootstatus = s3c2410wdt_get_bootstatus(wdt);
        wdt->wdt_device.parent = dev;
 
+       /*
+        * If "tmr_atboot" param is non-zero, start the watchdog right now. Also
+        * set WDOG_HW_RUNNING bit, so that watchdog core can kick the watchdog.
+        *
+        * If we're not enabling the watchdog, then ensure it is disabled if it
+        * has been left running from the bootloader or other source.
+        */
+       if (tmr_atboot) {
+               dev_info(dev, "starting watchdog timer\n");
+               s3c2410wdt_start(&wdt->wdt_device);
+               set_bit(WDOG_HW_RUNNING, &wdt->wdt_device.status);
+       } else {
+               s3c2410wdt_stop(&wdt->wdt_device);
+       }
+
        ret = watchdog_register_device(&wdt->wdt_device);
        if (ret)
                goto err_cpufreq;
@@ -612,17 +627,6 @@ static int s3c2410wdt_probe(struct platform_device *pdev)
        if (ret < 0)
                goto err_unregister;
 
-       if (tmr_atboot) {
-               dev_info(dev, "starting watchdog timer\n");
-               s3c2410wdt_start(&wdt->wdt_device);
-       } else {
-               /* if we're not enabling the watchdog, then ensure it is
-                * disabled if it has been left running from the bootloader
-                * or other source */
-
-               s3c2410wdt_stop(&wdt->wdt_device);
-       }
-
        platform_set_drvdata(pdev, wdt);
 
        /* print out a statement of readiness */