watchdog: imx_sc_wdt: continue if the wdog already enabled

if the wdog is already enabled, and try to enabled it again,
we should ignore the error and continue, rather than return
error.

Signed-off-by: Jacky Bai <ping.bai@nxp.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20231010074626.2787383-1-ping.bai@nxp.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

Author: JackyBai

drivers/watchdog/imx_sc_wdt.c

@@ -34,6 +34,7 @@
 
 #define SC_IRQ_WDOG			1
 #define SC_IRQ_GROUP_WDOG		1
+#define SC_TIMER_ERR_BUSY		10
 
 static bool nowayout = WATCHDOG_NOWAYOUT;
 module_param(nowayout, bool, 0000);
@@ -61,7 +62,9 @@ static int imx_sc_wdt_start(struct watchdog_device *wdog)
 
 	arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_START_WDOG,
 		      0, 0, 0, 0, 0, 0, &res);
-	if (res.a0)
+
+	/* Ignore if already enabled(SC_TIMER_ERR_BUSY) */
+	if (res.a0 && res.a0 != SC_TIMER_ERR_BUSY)
 		return -EACCES;
 
 	arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_SET_WDOG_ACT,