GICv3: Fix Dist restore for when the GIC is reset

If the GIC loses power during suspend, which the restore code was
written for, exit early in the post restore power sequence. This
prevents an assert from tripping, and the power sequence isn't needed
in this case anyways.
Signed-off-by: Derek Basehore <dbasehore@chromium.org>

drivers/arm/gic/v3/arm_gicv3_common.c

@@ -83,6 +83,15 @@ void arm_gicv3_distif_post_restore(unsigned int rdist_proc_num)
 	gicr_base = gicv3_driver_data->rdistif_base_addrs[rdist_proc_num];
 	assert(gicr_base);
 
+	/*
+	 * If the GIC had power removed, the GICR_WAKER state will be reset.
+	 * Since the GICR_WAKER.Sleep and GICR_WAKER.Quiescent bits are cleared,
+	 * we can exit early. This also prevents the following assert from
+	 * erroneously triggering.
+	 */
+	if (!(gicr_read_waker(gicr_base) & WAKER_SL_BIT))
+		return;
+
 	/*
 	 * Writes to GICR_WAKER.Sleep bit are ignored if GICR_WAKER.Quiescent
 	 * bit is not set. We should be alright on power on path, therefore