intel_adsp/ace: power: Lock interruption when power gate fails

In case the core is not power gated, waiti will restore intlevel. In
this case we lock interruption after it.

In the bug scenario, the host starts streaming and via SOF APIs, keeps a
lock to prevent Zephyr from entering PM_STATE_RUNTIME_IDLE. During the
test case, host removes this block and core0 is allowed to enter IDLE
state.

When core0 enters power gated state, interrrupts are left enabled (so
the core can be woken up when something happens). This leaves a race
where suitably timed interrupt will actually block entry to power gated
state and k_cpu_idle() in power_gate_entry() will return. This is rare,
but happens often enough that the relatively short test plan run on SOF
pull-requests will trigger this case.

Fixes zephyrproject-rtos#69807

Signed-off-by: Flavio Ceolin <[email protected]>
Signed-off-by: Anas Nashif <[email protected]>

soc/intel/intel_adsp/ace/power.c

@@ -176,6 +176,13 @@ void power_gate_entry(uint32_t core_id)
 	soc_cpus_active[core_id] = false;
 	sys_cache_data_flush_range(soc_cpus_active, sizeof(soc_cpus_active));
 	k_cpu_idle();
+
+	/* It is unlikely we get in here, but when this happens
+	 * we need to lock interruptions again.
+	 *
+	 * @note Zephyr looks PS.INTLEVEL to check if interruptions are locked.
+	 */
+	(void)arch_irq_lock();
 	z_xt_ints_off(0xffffffff);
 }