fix it87_wdt early reboot by reporting running timer

Some products, such as the Ugreen DXP4800 Plus NAS, ship with the it87
wdt enabled by the firmware and a broken BIOS option that does not
allow to change the time or turn it off. As this makes installing
Linux rather difficult, change the it87_wdt to report it running to
the watchdog core.

Signed-off-by: René Rebe <rene@exactco.de>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

diff --git a/drivers/watchdog/it87_wdt.c b/drivers/watchdog/it87_wdt.c
index 3b8488c86a2f3a769a7aed6032b11ea37b99c9e6..1d9f8591f38d879bd964b20436cf63afa3c086c4 100644 (file)
--- a/drivers/watchdog/it87_wdt.c
+++ b/drivers/watchdog/it87_wdt.c
@@ -188,6 +188,12 @@ static void _wdt_update_timeout(unsigned int t)
                superio_outb(t >> 8, WDTVALMSB);
 }
 
+/* Internal function, should be called after superio_select(GPIO) */
+static bool _wdt_running(void)
+{
+       return superio_inb(WDTVALLSB) || (max_units > 255 && superio_inb(WDTVALMSB));
+}
+
 static int wdt_update_timeout(unsigned int t)
 {
        int ret;
@@ -374,6 +380,12 @@ static int __init it87_wdt_init(void)
                }
        }
 
+       /* wdt already left running by firmware? */
+       if (_wdt_running()) {
+               pr_info("Left running by firmware.\n");
+               set_bit(WDOG_HW_RUNNING, &wdt_dev.status);
+       }
+
        superio_exit();
 
        if (timeout < 1 || timeout > max_units * 60) {