drivers: mbox: imx_mu: return early in ISR when done

Change the ISR code to return once all pended interrupts
are handled instead of continuing to iterate over
all channels. Common occurence is just for one interrupt
bit to be set so no need to check all bits in all channels
if only one bit is pending.

Signed-off-by: Mike J. Chen <[email protected]>

Author: mjchen0

drivers/mbox/mbox_nxp_imx_mu.c

@@ -181,7 +181,7 @@ static void mu_isr(const struct device *dev)
 {
 	struct nxp_imx_mu_data *data = dev->data;
 	const struct nxp_imx_mu_config *config = dev->config;
-	const uint32_t flags = MU_GetStatusFlags(config->base);
+	uint32_t flags = MU_GetStatusFlags(config->base);
 
 	for (int i_channel = 0; i_channel < MU_MAX_CHANNELS; i_channel++) {
 		/* Handle notification interrupt for the channel first and
@@ -199,6 +199,13 @@ static void mu_isr(const struct device *dev)
 				data->cb[i_channel](dev, i_channel, data->user_data[i_channel],
 						    NULL);
 			}
+			/* Clear the interrupt just handled and break
+			 * if no more pending.
+			 */
+			flags &= ~gen_int_mask;
+			if (flags == 0) {
+				break;
+			}
 		}
 
 		const uint32_t rx_int_mask = g_rx_flag_mask[i_channel];
@@ -211,6 +218,13 @@ static void mu_isr(const struct device *dev)
 				data->cb[i_channel](dev, i_channel, data->user_data[i_channel],
 						    &msg);
 			}
+			/* Clear the interrupt just handled and break
+			 * if no more pending.
+			 */
+			flags &= ~rx_int_mask;
+			if (flags == 0) {
+				break;
+			}
 		}
 	}
 }