diff --git a/drivers/irqchip/irq-armada-370-xp.c b/drivers/irqchip/irq-armada-370-xp.c
index e5738c5..f53eb71 100644
--- a/drivers/irqchip/irq-armada-370-xp.c
+++ b/drivers/irqchip/irq-armada-370-xp.c
@@ -401,10 +401,10 @@
 
 		if (is_chained) {
 			irq = irq_find_mapping(armada_370_xp_msi_inner_domain,
-					       msinr - 16);
+					       msinr - PCI_MSI_DOORBELL_START);
 			generic_handle_irq(irq);
 		} else {
-			irq = msinr - 16;
+			irq = msinr - PCI_MSI_DOORBELL_START;
 			handle_domain_irq(armada_370_xp_msi_inner_domain,
 					  irq, regs);
 		}