watchdog: imx7ulp_wdt: Check CMD32EN in wdog init

When bootloader has enabled the CMD32EN bit, switch to use 32bits
unlock command to unlock the CS register. Using 32bits command will
help on avoiding 16 bus cycle window violation for two 16 bits
commands.

Signed-off-by: Ye Li <[email protected]>
Signed-off-by: Alice Guo <[email protected]>
Reviewed-by: Jacky Bai <[email protected]>
Acked-by: Jason Liu <[email protected]>
Reviewed-by: Guenter Roeck <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Guenter Roeck <[email protected]>
Signed-off-by: Wim Van Sebroeck <[email protected]>

Author: Ye Li

drivers/watchdog/imx7ulp_wdt.c

@@ -180,11 +180,16 @@ static int imx7ulp_wdt_init(void __iomem *base, unsigned int timeout)
 
 	local_irq_disable();
 
-	mb();
-	/* unlock the wdog for reconfiguration */
-	writel_relaxed(UNLOCK_SEQ0, base + WDOG_CNT);
-	writel_relaxed(UNLOCK_SEQ1, base + WDOG_CNT);
-	mb();
+	val = readl(base + WDOG_CS);
+	if (val & WDOG_CS_CMD32EN) {
+		writel(UNLOCK, base + WDOG_CNT);
+	} else {
+		mb();
+		/* unlock the wdog for reconfiguration */
+		writel_relaxed(UNLOCK_SEQ0, base + WDOG_CNT);
+		writel_relaxed(UNLOCK_SEQ1, base + WDOG_CNT);
+		mb();
+	}
 
 	ret = imx7ulp_wdt_wait(base, WDOG_CS_ULK);
 	if (ret)