[PATCH] watchdog: imx_sc_wdt: Pretimeout should follow SCU firmware format

[Anson Huang]

SCU firmware calculates pretimeout based on current time stamp
instead of watchdog timeout stamp, need to convert the pretimeout
to SCU firmware's timeout value.

Fixes: 15f7d7fc5542 ("watchdog: imx_sc: Add pretimeout support")
Signed-off-by: Anson Huang <Anson.Huang@xxxxxxx>
---
 drivers/watchdog/imx_sc_wdt.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/watchdog/imx_sc_wdt.c b/drivers/watchdog/imx_sc_wdt.c
index 7ea5cf5..8ed89f0 100644
--- a/drivers/watchdog/imx_sc_wdt.c
+++ b/drivers/watchdog/imx_sc_wdt.c
@@ -99,8 +99,14 @@ static int imx_sc_wdt_set_pretimeout(struct watchdog_device *wdog,
 {
 	struct arm_smccc_res res;
 
+	/*
+	 * SCU firmware calculates pretimeout based on current time
+	 * stamp instead of watchdog timeout stamp, need to convert
+	 * the pretimeout to SCU firmware's timeout value.
+	 */
 	arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_SET_PRETIME_WDOG,
-		      pretimeout * 1000, 0, 0, 0, 0, 0, &res);
+		      (wdog->timeout - pretimeout) * 1000, 0, 0, 0,
+		      0, 0, &res);
 	if (res.a0)
 		return -EACCES;
 
-- 
2.7.4