From: René Rebe <rene@exactco.de>
Date: Mon, 17 Nov 2025 12:11:24 +0000 (+0100)
Subject: fix it87_wdt early reboot by reporting running timer
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=88b2ab346436f799b99894a3e9518a3ffa344524;p=thirdparty%2Flinux.git

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 3b8488c86a2f3..1d9f8591f38d8 100644
--- 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) {