SDEI: Mask events after CPU wakeup

The specification requires that, after wakeup from a CPU suspend, the
dispatcher must mask all events on the CPU. This patch adds the feature
to the SDEI dispatcher by subscribing to the PSCI suspend to power down
event, and masking all events on the PE.

Change-Id: I9fe1d1bc2a58379ba7bba953a8d8b275fc18902c
Signed-off-by: Jeenu Viswambharan <jeenu.viswambharan@arm.com>

services/std_svc/sdei/sdei_main.c

@@ -81,6 +81,17 @@ static void *sdei_cpu_on_init(const void *arg)
 	return NULL;
 }
 
+/* CPU initialisation after wakeup from suspend */
+static void *sdei_cpu_wakeup_init(const void *arg)
+{
+	SDEI_LOG("Events masked on %lx\n", read_mpidr_el1());
+
+	/* All PEs wake up with SDEI events masked */
+	sdei_pe_mask();
+
+	return 0;
+}
+
 /* Initialise an SDEI class */
 static void sdei_class_init(sdei_class_t class)
 {
@@ -1075,3 +1086,6 @@ uint64_t sdei_smc_handler(uint32_t smc_fid,
 
 /* Subscribe to PSCI CPU on to initialize per-CPU SDEI configuration */
 SUBSCRIBE_TO_EVENT(psci_cpu_on_finish, sdei_cpu_on_init);
+
+/* Subscribe to PSCI CPU suspend finisher for per-CPU configuration */
+SUBSCRIBE_TO_EVENT(psci_suspend_pwrdown_finish, sdei_cpu_wakeup_init);