fu.wei at linaro.org wrote:

+	if (action) {
+		irq = platform_get_irq(pdev, 0);
+		if (irq < 0) {
+			action = 0;
+			dev_warn(dev, "unable to get ws0 interrupt.\n");
+		} else {
+			if (devm_request_irq(dev, irq, sbsa_gwdt_interrupt, 0,
+					     pdev->name, gwdt)) {
+				action = 0;
+				dev_warn(dev, "unable to request IRQ %d.\n",
+					 irq);
+			}
+		}
+		if (!action)
+			dev_warn(dev, "falling back to signle stage mode.\n");
+	}
+
+	/*
+	 * Get the frequency of system counter from the cp15 interface of ARM
+	 * Generic timer. We don't need to check it, because if it returns "0",
+	 * system would panic in very early stage.
+	 */
+	gwdt->clk = arch_timer_get_cntfrq();
+	gwdt->refresh_base = rf_base;
+	gwdt->control_base = cf_base;

I think you need to ping the watchdog before enabling the interrupt, in 
case there is a pending interrupt.  This just happened to me in testing, 
so I recommend this:

	/*
	 * Get the frequency of system counter from the cp15 interface of ARM
	 * Generic timer. We don't need to check it, because if it returns "0",
	 * system would panic in very early stage.
	 */
	gwdt->clk = arch_timer_get_cntfrq();
	gwdt->refresh_base = rf_base;
	gwdt->control_base = cf_base;

	if (action) {
		irq = platform_get_irq(pdev, 0);
		if (irq < 0) {
			action = 0;
			dev_warn(dev, "unable to get ws0 interrupt.\n");
		} else {
			sbsa_gwdt_keepalive(&gwdt->wdd);
			if (devm_request_irq(dev, irq, sbsa_gwdt_interrupt, 0,
					     pdev->name, gwdt)) {
				action = 0;
				dev_warn(dev, "unable to request IRQ %d.\n",
					 irq);
			}
		}
		if (!action)
			dev_warn(dev, "falling back to single stage mode.\n");
	}

In fact, I think you need to move the "if (action) {" block near the end 
of sbsa_gwdt_probe().  We don't want to enable the interrupt until the 
watchdog is fully initialized.

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