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authorAndré Draszik <git@andred.net>2018-01-12 12:44:53 +0300
committerWim Van Sebroeck <wim@iguana.be>2018-01-21 14:44:58 +0300
commit392d39a863583eb6439e2ec543818250b57ef99d (patch)
tree9f645c1439d464b71ae6efee27cc7f3b055eb0c1 /drivers/watchdog/mt7621_wdt.c
parent0be267255cef64e1c58475baa7b25568355a3816 (diff)
downloadlinux-392d39a863583eb6439e2ec543818250b57ef99d.tar.xz
watchdog: mt7621: set WDOG_HW_RUNNING bit when appropriate
If the watchdog hardware is enabled/running during boot, e.g. due to a boot loader configuring it, we must tell the watchdog framework about this fact so that it can ping the watchdog until userspace opens the device and takes over control. Do so using the WDOG_HW_RUNNING flag that exists for exactly that use-case. Given the watchdog driver core doesn't know what timeout was originally set by whoever started the watchdog (boot loader), we make sure to update the timeout in the hardware according to what the watchdog core thinks it is. Signed-off-by: André Draszik <git@andred.net> Cc: linux-watchdog@vger.kernel.org Cc: John Crispin <john@phrozen.org> Reviewed-by: Guenter Roeck <Linux@roeck-us.net> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Diffstat (limited to 'drivers/watchdog/mt7621_wdt.c')
-rw-r--r--drivers/watchdog/mt7621_wdt.c19
1 files changed, 19 insertions, 0 deletions
diff --git a/drivers/watchdog/mt7621_wdt.c b/drivers/watchdog/mt7621_wdt.c
index db38f8017218..eec57e5e1eae 100644
--- a/drivers/watchdog/mt7621_wdt.c
+++ b/drivers/watchdog/mt7621_wdt.c
@@ -105,6 +105,11 @@ static int mt7621_wdt_bootcause(void)
return 0;
}
+static int mt7621_wdt_is_running(struct watchdog_device *w)
+{
+ return !!(rt_wdt_r32(TIMER_REG_TMR1CTL) & TMR1CTL_ENABLE);
+}
+
static const struct watchdog_info mt7621_wdt_info = {
.identity = "Mediatek Watchdog",
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
@@ -144,6 +149,20 @@ static int mt7621_wdt_probe(struct platform_device *pdev)
watchdog_init_timeout(&mt7621_wdt_dev, mt7621_wdt_dev.max_timeout,
&pdev->dev);
watchdog_set_nowayout(&mt7621_wdt_dev, nowayout);
+ if (mt7621_wdt_is_running(&mt7621_wdt_dev)) {
+ /*
+ * Make sure to apply timeout from watchdog core, taking
+ * the prescaler of this driver here into account (the
+ * boot loader might be using a different prescaler).
+ *
+ * To avoid spurious resets because of different scaling,
+ * we first disable the watchdog, set the new prescaler
+ * and timeout, and then re-enable the watchdog.
+ */
+ mt7621_wdt_stop(&mt7621_wdt_dev);
+ mt7621_wdt_start(&mt7621_wdt_dev);
+ set_bit(WDOG_HW_RUNNING, &mt7621_wdt_dev.status);
+ }
ret = watchdog_register_device(&mt7621_wdt_dev);