IRQCHIP: brcmstb-l2: don't clear wakeable interrupts at init time

Wakeable interrupts might be pending at boot/init time, because wakeup
interrupts might have triggered a resume from S5. So don't clear such
wakeups.

This means that any driver which requests a wakeable interrupt bit
should be prepared to handle an interrupt as soon as they call
request_irq(). (This is technically already the correct development
practice, but some drivers probably expect not to receive interrupts
until they have performed some I/O.)

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Cc: f.fainelli@gmail.com
Cc: jaedon.shin@gmail.com
Cc: abrestic@chromium.org
Cc: tglx@linutronix.de
Cc: jason@lakedaemon.net
Cc: jogo@openwrt.org
Cc: arnd@arndb.de
Cc: computersforpeace@gmail.com
Cc: linux-mips@linux-mips.org
Cc: devicetree@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/8840/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

drivers/irqchip/irq-brcmstb-l2.c

@@ -136,7 +136,11 @@ int __init brcmstb_l2_intc_of_init(struct device_node *np,
 
 	/* Disable all interrupts by default */
 	writel(0xffffffff, data->base + CPU_MASK_SET);
-	writel(0xffffffff, data->base + CPU_CLEAR);
+
+	/* Wakeup interrupts may be retained from S5 (cold boot) */
+	data->can_wake = of_property_read_bool(np, "brcm,irq-can-wake");
+	if (!data->can_wake)
+		writel(0xffffffff, data->base + CPU_CLEAR);
 
 	data->parent_irq = irq_of_parse_and_map(np, 0);
 	if (!data->parent_irq) {
@@ -188,8 +192,7 @@ int __init brcmstb_l2_intc_of_init(struct device_node *np,
 	ct->chip.irq_suspend = brcmstb_l2_intc_suspend;
 	ct->chip.irq_resume = brcmstb_l2_intc_resume;
 
-	if (of_property_read_bool(np, "brcm,irq-can-wake")) {
-		data->can_wake = true;
+	if (data->can_wake) {
 		/* This IRQ chip can wake the system, set all child interrupts
 		 * in wake_enabled mask
 		 */