spmi: spmi-pmic-arb: check apid against limits before calling irq handler

Check that the apid for an SPMI interrupt falls between the
min_apid and max_apid that can be handled by the APPS processor
before invoking the per-apid interrupt handler:
periph_interrupt().

This avoids an access violation in rare cases where the status
bit is set for an interrupt that is not owned by the APPS
processor.

Change-Id: Ib74cb4ae7be9849f0243659bb4c1435340e1e087
Signed-off-by: David Collins <collinsd@codeaurora.org>

drivers/spmi/spmi-pmic-arb.c

@@ -535,6 +535,12 @@ static void pmic_arb_chained_irq(struct irq_desc *desc)
 			id = ffs(status) - 1;
 			status &= ~BIT(id);
 			apid = id + i * 32;
+			if (apid < pmic_arb->min_apid
+			    || apid > pmic_arb->max_apid) {
+				WARN_ONCE(true, "spurious spmi irq received for apid=%d\n",
+					apid);
+				continue;
+			}
 			enable = readl_relaxed(
 					ver_ops->acc_enable(pmic_arb, apid));
 			if (enable & SPMI_PIC_ACC_ENABLE_BIT)