[PATCH AUTOSEL 5.4 084/134] watchdog: imx7ulp: Fix reboot hang

[Sasha Levin]

From: Fabio Estevam <festevam@xxxxxxxxx>

[ Upstream commit 6083ab7b2f3f25022e2e8f4c42f14a8521f47873 ]

The following hang is observed when a 'reboot' command is issued:

# reboot
# Stopping network: OK
Stopping klogd: OK
Stopping syslogd: OK
umount: devtmpfs busy - remounted read-only
[    8.612079] EXT4-fs (mmcblk0p2): re-mounted. Opts: (null)
The system is going down NOW!
Sent SIGTERM to all processes
Sent SIGKILL to all processes
Requesting system reboot
[   10.694753] reboot: Restarting system
[   11.699008] Reboot failed -- System halted

Fix this problem by adding a .restart ops member.

Fixes: 41b630f41bf7 ("watchdog: Add i.MX7ULP watchdog support")
Signed-off-by: Fabio Estevam <festevam@xxxxxxxxx>
Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20191029174037.25381-1-festevam@xxxxxxxxx
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Wim Van Sebroeck <wim@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/watchdog/imx7ulp_wdt.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/watchdog/imx7ulp_wdt.c b/drivers/watchdog/imx7ulp_wdt.c
index 5ce51026989a4..ba5d535a6db2e 100644
--- a/drivers/watchdog/imx7ulp_wdt.c
+++ b/drivers/watchdog/imx7ulp_wdt.c
@@ -106,12 +106,28 @@ static int imx7ulp_wdt_set_timeout(struct watchdog_device *wdog,
 	return 0;
 }
 
+static int imx7ulp_wdt_restart(struct watchdog_device *wdog,
+			       unsigned long action, void *data)
+{
+	struct imx7ulp_wdt_device *wdt = watchdog_get_drvdata(wdog);
+
+	imx7ulp_wdt_enable(wdt->base, true);
+	imx7ulp_wdt_set_timeout(&wdt->wdd, 1);
+
+	/* wait for wdog to fire */
+	while (true)
+		;
+
+	return NOTIFY_DONE;
+}
+
 static const struct watchdog_ops imx7ulp_wdt_ops = {
 	.owner = THIS_MODULE,
 	.start = imx7ulp_wdt_start,
 	.stop  = imx7ulp_wdt_stop,
 	.ping  = imx7ulp_wdt_ping,
 	.set_timeout = imx7ulp_wdt_set_timeout,
+	.restart = imx7ulp_wdt_restart,
 };
 
 static const struct watchdog_info imx7ulp_wdt_info = {
-- 
2.20.1