[PATCH 1/2] ARM/MXS/i.MX28: recognize watchdog reset

[Marc Kleine-Budde]

From: Steffen Trumtrar <s.trumtrar at pengutronix.de>

When a watchdog timeout is set in the linux kernel, the FORCE_UPDATE bit is set.
Use this to recognize a system reset that was triggered by the watchdog.
Since only the wdt part of the kernel driver sets this bit, this is a safe
distinguishing feature.

Signed-off-by: Steffen Trumtrar <s.trumtrar at pengutronix.de>
Signed-off-by: Marc Kleine-Budde <mkl at pengutronix.de>
---
 drivers/watchdog/im28wd.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/watchdog/im28wd.c b/drivers/watchdog/im28wd.c
index 3e73ecd62e7c..a9093a7b51c9 100644
--- a/drivers/watchdog/im28wd.c
+++ b/drivers/watchdog/im28wd.c
@@ -176,6 +176,13 @@ static void __maybe_unused imx28_detect_reset_source(const struct imx28_wd *p)
 		reset_source_set(RESET_RST);
 		return;
 	}
+	reg = readl(p->regs + MXS_RTC_PERSISTENT1);
+	if (reg & MXS_RTC_PERSISTENT1_FORCE_UPDATER) {
+		writel(MXS_RTC_PERSISTENT1_FORCE_UPDATER,
+			p->regs + MXS_RTC_PERSISTENT1 + MXS_RTC_CLR_ADDR);
+		reset_source_set(RESET_WDG);
+		return;
+	}
 
 	reset_source_set(RESET_RST);
 }
-- 
2.1.4