sample: mbox: Introduce MBOX NRFX IPC sample

Make use of the new MBOX APIs to create a ping-pong sample application.
This sample is using the NRFX IPC peripheral to send and receive signals
on different channels

Signed-off-by: Carlo Caione <ccaione@baylibre.com>

samples/drivers/mbox/CMakeLists.txt

@@ -0,0 +1,36 @@
+#
+# Copyright (c) 2021 Carlo Caione <ccaione@baylibre.com>
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+cmake_minimum_required(VERSION 3.20.0)
+
+set(REMOTE_ZEPHYR_DIR ${CMAKE_CURRENT_BINARY_DIR}/mbox_ipc_remote-prefix/src/mbox_ipc_remote-build/zephyr)
+
+if("${BOARD}" STREQUAL "nrf5340dk_nrf5340_cpuapp")
+  set(BOARD_REMOTE "nrf5340dk_nrf5340_cpunet")
+else()
+  message(FATAL_ERROR "${BOARD} is not supported for this sample")
+endif()
+
+message(INFO " ${BOARD} compile as Main in this sample")
+
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(mbox_ipc)
+
+enable_language(C ASM)
+
+target_sources(app PRIVATE src/main.c)
+
+include(ExternalProject)
+
+ExternalProject_Add(
+  mbox_ipc_remote
+  SOURCE_DIR ${APPLICATION_SOURCE_DIR}/remote
+  INSTALL_COMMAND ""      # This particular build system has no install command
+  CMAKE_CACHE_ARGS -DBOARD:STRING=${BOARD_REMOTE}
+  BUILD_BYPRODUCTS "${REMOTE_ZEPHYR_DIR}/${KERNEL_BIN_NAME}"
+  # NB: Do we need to pass on more CMake variables?
+  BUILD_ALWAYS True
+)

samples/drivers/mbox/boards/nrf5340dk_nrf5340_cpuapp.conf

@@ -0,0 +1,2 @@
+CONFIG_MBOX_NRFX=y
+CONFIG_BOARD_ENABLE_CPUNET=y

samples/drivers/mbox/boards/nrf5340dk_nrf5340_cpuapp.overlay

@@ -0,0 +1,18 @@
+/*
+ * Copyright (c) 2021 Carlo Caione <ccaione@baylibre.com>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/ {
+	soc {
+		mbox: mbox@2a000 {
+			compatible = "nordic,mbox-nrf-ipc";
+			reg = <0x2a000 0x1000>;
+			tx-mask = <0x0000ffff>;
+			rx-mask = <0x0000ffff>;
+			interrupts = <42 NRF_DEFAULT_IRQ_PRIORITY>;
+			status = "okay";
+		};
+	};
+};

samples/drivers/mbox/prj.conf

@@ -0,0 +1,2 @@
+CONFIG_PRINTK=y
+CONFIG_MBOX=y

samples/drivers/mbox/remote/CMakeLists.txt

@@ -0,0 +1,18 @@
+#
+# Copyright (c) 2021 Carlo Caione <ccaione@baylibre.com>
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+cmake_minimum_required(VERSION 3.20.0)
+
+if("${BOARD}" STREQUAL "nrf5340dk_nrf5340_cpunet")
+  message(INFO " ${BOARD} compile as remote in this sample")
+else()
+  message(FATAL_ERROR "${BOARD} is not supported for this sample")
+endif()
+
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(mbox_ipc_remote)
+
+target_sources(app PRIVATE src/main.c)

samples/drivers/mbox/remote/boards/nrf5340dk_nrf5340_cpunet.conf

@@ -0,0 +1 @@
+CONFIG_MBOX_NRFX=y

samples/drivers/mbox/remote/boards/nrf5340dk_nrf5340_cpunet.overlay

@@ -0,0 +1,18 @@
+/*
+ * Copyright (c) 2021 Carlo Caione <ccaione@baylibre.com>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/ {
+	soc {
+		mbox: mbox@41012000 {
+			compatible = "nordic,mbox-nrf-ipc";
+			reg = <0x41012000 0x1000>;
+			tx-mask = <0x0000ffff>;
+			rx-mask = <0x0000ffff>;
+			interrupts = <18 NRF_DEFAULT_IRQ_PRIORITY>;
+			status = "okay";
+		};
+	};
+};

samples/drivers/mbox/remote/prj.conf

@@ -0,0 +1,2 @@
+CONFIG_STDOUT_CONSOLE=n
+CONFIG_MBOX=y

samples/drivers/mbox/remote/src/main.c

@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2021 Carlo Caione <ccaione@baylibre.com>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <zephyr.h>
+#include <drivers/mbox.h>
+
+#define TX_ID (0)
+#define RX_ID (1)
+
+static void callback(const struct device *dev, uint32_t channel,
+		     void *user_data, struct mbox_msg *data)
+{
+	printk("Pong (on channel %d)\n", channel);
+}
+
+void main(void)
+{
+	struct mbox_channel tx_channel;
+	struct mbox_channel rx_channel;
+	const struct device *dev;
+
+	printk("Hello from NET\n");
+
+	dev = DEVICE_DT_GET(DT_NODELABEL(mbox));
+
+	mbox_init_channel(&tx_channel, dev, TX_ID);
+	mbox_init_channel(&rx_channel, dev, RX_ID);
+
+	if (mbox_set_enabled(&rx_channel, 1)) {
+		printk("mbox_set_enable() error\n");
+		return;
+	}
+
+	mbox_register_callback(&rx_channel, callback, NULL);
+
+	while (1) {
+
+		printk("Ping (on channel %d)\n", tx_channel.id);
+
+		if (mbox_send(&tx_channel, NULL) < 0) {
+			printk("mbox_send() error\n");
+			return;
+		}
+
+		k_sleep(K_MSEC(3000));
+	}
+}

samples/drivers/mbox/sample.yaml

@@ -0,0 +1,9 @@
+sample:
+    name: MBOX IPC sample
+tests:
+    sample.drivers.mbox:
+        platform_allow: nrf5340dk_nrf5340_cpuapp
+        integration_platforms:
+          - nrf5340dk_nrf5340_cpuapp
+        tags: mbox
+        build_only: true

samples/drivers/mbox/src/main.c

@@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 2021 Carlo Caione <ccaione@baylibre.com>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <zephyr.h>
+#include <drivers/mbox.h>
+
+#define TX_ID (1)
+#define RX_ID (0)
+
+static void callback(const struct device *dev, uint32_t channel,
+		     void *user_data, struct mbox_msg *data)
+{
+	printk("Pong (on channel %d)\n", channel);
+}
+
+void main(void)
+{
+	struct mbox_channel tx_channel;
+	struct mbox_channel rx_channel;
+	const struct device *dev;
+
+	printk("Hello from APP\n");
+
+	dev = DEVICE_DT_GET(DT_NODELABEL(mbox));
+
+	mbox_init_channel(&tx_channel, dev, TX_ID);
+	mbox_init_channel(&rx_channel, dev, RX_ID);
+
+	if (mbox_set_enabled(&rx_channel, 1)) {
+		printk("mbox_set_enable() error\n");
+		return;
+	}
+
+	mbox_register_callback(&rx_channel, callback, NULL);
+
+	while (1) {
+		k_sleep(K_MSEC(2000));
+
+		printk("Ping (on channel %d)\n", tx_channel.id);
+
+		if (mbox_send(&tx_channel, NULL) < 0) {
+			printk("mbox_send() error\n");
+			return;
+		}
+	}
+}