samples: boards: nxp: s32: create sample mbox

The sample supports ping-pong loopback data on a MBOX channel
within one core.
The expected received data must match the sent data when running
the sample.

Signed-off-by: Cong Nguyen Huu <cong.nguyenhuu@nxp.com>

Author: congnguyenhuu

samples/boards/nxp/s32/mbox/CMakeLists.txt

@@ -0,0 +1,9 @@
+# Copyright 2025 NXP
+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.20.0)
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(mbox)
+
+FILE(GLOB app_sources src/*.c)
+target_sources(app PRIVATE ${app_sources})

samples/boards/nxp/s32/mbox/README.rst

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+.. zephyr:code-sample:: nxp_s32_mbox
+   :name: NXP S32 MBOX
+
+   Perform NXP S32 mailbox communication using the MBOX API with data.
+
+Overview
+********
+
+The sample supports ping-pong loopback data on a mbox channel within one core.
+
+Building and Running
+********************
+
+Building and running the sample, example for s32z2xxdc2/s32z270/rtu0:
+
+.. zephyr-app-commands::
+   :zephyr-app: samples/boards/nxp/s32/mbox
+   :board: s32z2xxdc2/s32z270/rtu0
+   :goals: build flash
+
+Results from running the sample, example for s32z2xxdc2/s32z270/rtu0:
+
+.. code-block:: console
+
+   *** Booting Zephyr OS build v4.1.0-3644-ga4ee89a96597 ***
+   mbox_data demo started
+   send (on channel 0) value: 0
+   received (on channel 0) value: 0
+   send (on channel 0) value: 1
+   received (on channel 0) value: 1
+   ...
+   send (on channel 0) value: 98
+   received (on channel 0) value: 98
+   send (on channel 0) value: 99
+   received (on channel 0) value: 99
+   mbox_data demo ended

samples/boards/nxp/s32/mbox/boards/s32z2xxdc2_s32z270_rtu0.overlay

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+/*
+ * Copyright 2025 NXP
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/ {
+	mbox-consumer {
+		compatible = "vnd,mbox-consumer";
+		mboxes = <&mru0 0>, <&mru0 0>;
+		mbox-names = "tx", "rx";
+	};
+};
+
+&mru0 {
+	rx-channels = <1>;
+	status = "okay";
+};

samples/boards/nxp/s32/mbox/boards/s32z2xxdc2_s32z270_rtu1.overlay

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+/*
+ * Copyright 2025 NXP
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/ {
+	mbox-consumer {
+		compatible = "vnd,mbox-consumer";
+		mboxes = <&mru4 0>, <&mru4 0>;
+		mbox-names = "tx", "rx";
+	};
+};
+
+&mru4 {
+	rx-channels = <1>;
+	status = "okay";
+};

samples/boards/nxp/s32/mbox/prj.conf

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+CONFIG_PRINTK=y
+CONFIG_MBOX=y

samples/boards/nxp/s32/mbox/sample.yaml

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+sample:
+  name: NXP S32 MBOX sample
+tests:
+  sample.boards.nxp_s32.mbox:
+    tags: mbox
+    filter: dt_compat_enabled("vnd,mbox-consumer")
+    platform_allow:
+      - s32z2xxdc2/s32z270/rtu0
+      - s32z2xxdc2/s32z270/rtu1
+      - s32z2xxdc2@D/s32z270/rtu0
+      - s32z2xxdc2@D/s32z270/rtu1
+    harness: console
+    harness_config:
+      type: multi_line
+      ordered: false
+      regex:
+        - "send .+ value: 0"
+        - "received .+ value: 0"
+        - "send .+ value: 1"
+        - "received .+ value: 1"
+        - "send .+ value: 41"
+        - "received .+ value: 41"
+        - "send .+ value: 42"
+        - "received .+ value: 42"
+        - "send .+ value: 98"
+        - "received .+ value: 98"
+        - "send .+ value: 99"
+        - "received .+ value: 99"

samples/boards/nxp/s32/mbox/src/main.c

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+/*
+ * Copyright 2025 NXP
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/kernel.h>
+#include <zephyr/drivers/mbox.h>
+
+static K_SEM_DEFINE(g_mbox_data_rx_sem, 0, 1);
+
+static mbox_channel_id_t g_mbox_received_data;
+static mbox_channel_id_t g_mbox_received_channel;
+
+static void callback(const struct device *dev, mbox_channel_id_t channel_id, void *user_data,
+		     struct mbox_msg *data)
+{
+	memcpy(&g_mbox_received_data, data->data, data->size);
+	g_mbox_received_channel = channel_id;
+
+	k_sem_give(&g_mbox_data_rx_sem);
+}
+
+int main(void)
+{
+	const struct mbox_dt_spec tx_channel = MBOX_DT_SPEC_GET(DT_PATH(mbox_consumer), tx);
+	const struct mbox_dt_spec rx_channel = MBOX_DT_SPEC_GET(DT_PATH(mbox_consumer), rx);
+	struct mbox_msg msg = {0};
+	uint32_t message = 0;
+
+	printk("mbox_data demo started\n");
+
+	const int max_transfer_size_bytes = mbox_mtu_get_dt(&tx_channel);
+	/* Sample currently supports only transfer size up to 4 bytes */
+	if ((max_transfer_size_bytes < 0) || (max_transfer_size_bytes > 4)) {
+		printk("mbox_mtu_get() error\n");
+		return 0;
+	}
+
+	if (mbox_register_callback_dt(&rx_channel, callback, NULL)) {
+		printk("mbox_register_callback() error\n");
+		return 0;
+	}
+
+	if (mbox_set_enabled_dt(&rx_channel, 1)) {
+		printk("mbox_set_enable() error\n");
+		return 0;
+	}
+
+	while (message < 100) {
+		msg.data = &message;
+		msg.size = max_transfer_size_bytes;
+
+		printk("send (on channel %d) value: %d\n", tx_channel.channel_id, message);
+		if (mbox_send_dt(&tx_channel, &msg) < 0) {
+			printk("mbox_send() error\n");
+			return 0;
+		}
+
+		k_sem_take(&g_mbox_data_rx_sem, K_FOREVER);
+		message = g_mbox_received_data;
+
+		printk("received (on channel %d) value: %d\n", g_mbox_received_channel,
+		       message);
+		message++;
+	}
+
+	printk("mbox_data demo ended\n");
+	return 0;
+}