samples: boards: stm32 hello_word application running in XiP mode

Samples to demonstrate the XiP mode when using an external NOR flash
in MemoryMapped mode
Defines the partition for the external memory of the stm32H5 disco

Signed-off-by: Francois Ramu <[email protected]>

Author: FRASTM

samples/boards/st/hello_world_xip/CMakeLists.txt

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+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.20.0)
+
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(hello_world_xip)
+
+target_sources(app PRIVATE src/main.c)

samples/boards/st/hello_world_xip/README.rst

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+.. _hello_world_xip:
+
+Hello World in XiP
+##################
+
+Overview
+********
+
+A simple sample that can be used with any :ref:`supported board <boards>`
+which has an external NOR octo- or quad- flash and
+prints "Hello World from external flash" to the console.
+The application is built and linked and downloaded in the external flash
+while the mcuboot is built and downloaded for the internal flash
+There is an overlay to set the partition in the external flash
+
+.. code-block:: console
+
+    chosen {
+        zephyr,flash = &mx25lm51245;
+        zephyr,flash-controller = &mx25lm51245;
+        zephyr,code-partition = &slot0_partition;
+    };
+
+
+Building and Running
+********************
+
+This application can be built with
+west build -p always -b stm32h573i_dk samples/boards/st/hello_world_xip/ --sysbuild -- -DSB_CONFIG_BOOTLOADER_MCUBOOT=y
+Download the build/mcuboot/zephyr/zephyr.bin at internal flash address 0x08000000
+Download the build/hello_world_xip/zephyr/zephyr.signed.bin at internal flash address 0x90000000 (chosen zephyr,code-partition)
+and executed on stm32h573i_dk as follows:
+
+.. zephyr-app-commands::
+   :zephyr-app: samples/boards/st/hello_world_xip
+   :host-os: unix
+   :board: stm32h573i_dk
+   :goals: run
+   :compact:
+
+To build for another board, change "stm32h573i_dk" above to that board's name.
+
+Sample Output
+=============
+Code is executed in the external flash which has been configured in Memory Mapped mode
+by the mcuboot.
+
+
+.. code-block:: console
+
+   *** Booting MCUboot v2.1.0-rc1-276-g540654e87167 ***
+   *** Using Zephyr OS build v4.1.0-2353-g0a25f40a19b5 ***                   
+   I: Starting bootloader                                                    
+   I: Primary image: magic=unset, swap_type=0x1, copy_done=0x3, image_ok=0x3 
+   I: Secondary image: magic=unset, swap_type=0x1, copy_done=0x3, image_ok=0x3
+   I: Boot source: none                                                      
+   I: Image index: 0, Swap type: none                                        
+   I: Bootloader chainload address offset: 0x0                               
+   I: Image version: v0.0.0                                                  
+   I: Jumping to the first image slot                                        
+   *** Booting Zephyr OS build v4.1.0-2353-g0a25f40a19b5 ***                 
+   Hello World! from external flash  stm32h573i_dk                           
+   --> PC at 0x9000092a                 
+
+The PC shows that code is being executed in the external flash.

samples/boards/st/hello_world_xip/boards/stm32h573i_dk.overlay

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+/*
+ * Copyright (c) 2025 STMicroelectronics
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/*
+ * Define the device, controller and partition to be the external memory
+ * for running the application in external NOR from MCUboot
+ */
+
+/ {
+	chosen {
+		zephyr,flash = &mx25lm51245;
+		zephyr,flash-controller = &mx25lm51245;
+		zephyr,code-partition = &slot0_partition;
+	};
+};

samples/boards/st/hello_world_xip/prj.conf

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+#CONFIG_XIP=y

samples/boards/st/hello_world_xip/sample.yaml

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+sample:
+  description: Hello World sample from external flash
+    application
+  name: hello world xip
+tests:
+  sample.boards.st.hello_world_xip:
+    tags: introduction
+    sysbuild: true
+    extra_args:
+      - SB_CONFIG_BOOTLOADER_MCUBOOT=y
+    integration_platforms:
+      - b_u585i_iot02a
+    platform_allow:
+      - stm32h573i_dk
+      - b_u585i_iot02a

samples/boards/st/hello_world_xip/src/main.c

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+/*
+ * Copyright (c) 2025 STMicroelectronics
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <stdio.h>
+#include <zephyr/kernel.h>
+#include <zephyr/drivers/gpio.h>
+#include <zephyr/toolchain/common.h>
+
+/* 1000 msec = 1 sec */
+#define SLEEP_TIME_MS   1000
+
+/* The devicetree node identifier for the "led0" alias. */
+#define LED0_NODE DT_ALIAS(led0)
+
+/*
+ * A build error on this line means your board is unsupported.
+ * See the sample documentation for information on how to fix this.
+ */
+static const struct gpio_dt_spec led0 = GPIO_DT_SPEC_GET(LED0_NODE, gpios);
+
+/* Inline Function to display the PC register --> proove where the application is running */
+ALWAYS_INLINE __STATIC_INLINE uint32_t __get_PC(void)
+{
+	register uint32_t result;
+
+	__ASM volatile ("MOV %0, PC\n" : "=r" (result));
+	return result;
+}
+
+int main(void)
+{
+	int ret;
+
+	printk("Hello World! from external flash  %s\n", CONFIG_BOARD);
+	printf("--> PC at 0x%x\n", __get_PC());
+
+	if (!gpio_is_ready_dt(&led0)) {
+		return -1;
+	}
+
+	ret = gpio_pin_configure_dt(&led0, GPIO_OUTPUT_ACTIVE);
+	if (ret < 0) {
+		return -1;
+	}
+
+	while (1) {
+		ret = gpio_pin_toggle_dt(&led0);
+		if (ret < 0) {
+			return -1;
+		}
+
+		k_msleep(SLEEP_TIME_MS);
+	}
+	return 0;
+}