dfu: Add custom device update

Adds a custom device update option to the DFU subsystem
Signed-off-by: Mathijs Meulendijks <mathijs.meulendijks@unitial.tech>

doc/nrf/libraries/dfu/dfu_target.rst

@@ -49,6 +49,7 @@ The DFU target library supports the following types of firmware upgrades:
 * Modem delta upgrades
 * Full modem firmware upgrades
 * SUIT-style upgrades
+* Custom upgrades
 
 MCUboot-style upgrades
 ----------------------
@@ -167,6 +168,13 @@ When all image data transfers are completed, the application using the DFU targe
    The application must schedule the upgrade of all images at once using the :c:func:`dfu_target_schedule_update` function.
    During this operation, the manifests stored in the ``dfu_partition`` partition will be processed.
 
+Custom upgrades
+-------------------
+
+This firmware upgrade supports custom updates for external peripherals or other custom firmware. 
+To use this feature, the application must implement the custom upgrade logic by applying the functions defined in the :file:`include/dfu/dfu_target_custom.h` file.
+
+
 Configuration
 *************
 
@@ -193,6 +201,7 @@ You can disable support for specific DFU targets using the following options:
 * :kconfig:option:`CONFIG_DFU_TARGET_MCUBOOT`
 * :kconfig:option:`CONFIG_DFU_TARGET_MODEM_DELTA`
 * :kconfig:option:`CONFIG_DFU_TARGET_FULL_MODEM`
+* :kconfig:option:`CONFIG_DFU_TARGET_CUSTOM`
 
 Maintaining writing progress after reboot
 =========================================

include/dfu/dfu_target.h

@@ -38,6 +38,8 @@ enum dfu_target_image_type {
 	DFU_TARGET_IMAGE_TYPE_SMP = 8,
 	/** SUIT Envelope */
 	DFU_TARGET_IMAGE_TYPE_SUIT = 16,
+	/** Custom update implementation, e.g. for external MCU */
+	DFU_TARGET_IMAGE_TYPE_CUSTOM = 32,
 	/** Any application image type */
 	DFU_TARGET_IMAGE_TYPE_ANY_APPLICATION = DFU_TARGET_IMAGE_TYPE_MCUBOOT,
 	/** Any modem image */
@@ -46,7 +48,7 @@ enum dfu_target_image_type {
 	/** Any DFU image type */
 	DFU_TARGET_IMAGE_TYPE_ANY =
 		(DFU_TARGET_IMAGE_TYPE_MCUBOOT | DFU_TARGET_IMAGE_TYPE_MODEM_DELTA |
-		 DFU_TARGET_IMAGE_TYPE_FULL_MODEM),
+		 DFU_TARGET_IMAGE_TYPE_FULL_MODEM | DFU_TARGET_IMAGE_TYPE_CUSTOM),
 };
 
 enum dfu_target_evt_id {

include/dfu/dfu_target_custom.h

@@ -0,0 +1,92 @@
+/*
+ * Copyright (c) 2024 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+
+/**
+ * @file dfu_target_custom.h
+ * @defgroup dfu_target_custom Custom DFU Target
+ * @{
+ * @brief Custom DFU (Device Firmware Update) target implementation.
+ *
+ * This file contains the function declarations for a custom DFU target implementation.
+ * It provides function prototypess for identifying, initializing, writing, and finalizing a custom
+ * firmware update process.
+ */
+
+#ifndef DFU_TARGET_CUSTOM_H__
+#define DFU_TARGET_CUSTOM_H__
+
+#include <dfu/dfu_target.h>
+#include <stddef.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+/**
+ * @brief Identifies if the provided buffer contains a custom firmware image.
+ *
+ * @param[in] buf Pointer to the buffer containing the potential firmware image.
+ * @retval true if the buffer contains a valid custom firmware image, false otherwise.
+ */
+bool dfu_target_custom_identify(const void *const buf);
+
+/**
+ * @brief Initializes the custom DFU target.
+ *
+ * @param[in] file_size Size of the firmware file to be written.
+ * @param[in] img_num Image number for multi-image DFU.
+ * @param[in] cb Callback function to be called during the DFU process.
+ * @retval 0 on success, negative errno code on failure.
+ */
+int dfu_target_custom_init(size_t file_size, int img_num, dfu_target_callback_t cb);
+
+/**
+ * @brief Gets the current write offset for the custom DFU target.
+ *
+ * @param[out] offset Pointer to store the current write offset.
+ * @retval 0 on success, negative errno code on failure.
+ */
+int dfu_target_custom_offset_get(size_t *offset);
+
+/**
+ * @brief Writes data to the custom DFU target.
+ *
+ * @param[in] buf Pointer to the buffer containing the data to be written.
+ * @param[in] len Length of the data to be written.
+ * @retval 0 on success, negative errno code on failure.
+ */
+int dfu_target_custom_write(const void *const buf, size_t len);
+
+/**
+ * @brief Releases resources and finalizes the custom DFU process if successful.
+ *
+ * @param[in] successful true if the DFU process was successful, false otherwise.
+ * @retval 0 on success, negative errno code on failure.
+ */
+int dfu_target_custom_done(bool successful);
+
+/**
+ * @brief Schedules an update for the custom DFU target.
+ *
+ * @param[in] img_num Image number for multi-image DFU.
+ * @retval 0 on success, negative errno code on failure.
+ */
+int dfu_target_custom_schedule_update(int img_num);
+
+/**
+ * @brief  Release resources and erase the download area.
+ *
+ * Cancel any ongoing updates.
+ *
+ * @retval 0 on success, negative errno code on failure.
+ */
+int dfu_target_custom_reset(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* DFU_TARGET_SUIT_H__ */
+/**@} */

subsys/dfu/dfu_target/Kconfig

@@ -153,6 +153,12 @@ config DFU_TARGET_REBOOT_RESET_DELAY_MS
 
 endif # DFU_TARGET_SUIT
 
+config DFU_TARGET_CUSTOM
+	bool "Custom application controlled update support"
+	default n
+	help
+	  Enable support for custom updates using DFU target
+
 module=DFU_TARGET
 module-dep=LOG
 module-str=Device Firmware Upgrade

subsys/dfu/dfu_target/src/dfu_target.c

@@ -38,6 +38,10 @@ DEF_DFU_TARGET(smp);
 #include "dfu/dfu_target_suit.h"
 DEF_DFU_TARGET(suit);
 #endif
+#ifdef CONFIG_DFU_TARGET_CUSTOM
+#include "dfu/dfu_target_custom.h"
+DEF_DFU_TARGET(custom);
+#endif
 
 #define MIN_SIZE_IDENTIFY_BUF 32
 
@@ -65,6 +69,11 @@ enum dfu_target_image_type dfu_target_img_type(const void *const buf, size_t len
 	if (dfu_target_full_modem_identify(buf)) {
 		return DFU_TARGET_IMAGE_TYPE_FULL_MODEM;
 	}
+#endif
+#ifdef CONFIG_DFU_TARGET_CUSTOM
+	if (dfu_target_custom_identify(buf)) {
+		return DFU_TARGET_IMAGE_TYPE_CUSTOM;
+	}
 #endif
 	LOG_ERR("No supported image type found");
 	return DFU_TARGET_IMAGE_TYPE_NONE;
@@ -113,6 +122,11 @@ int dfu_target_init(int img_type, int img_num, size_t file_size, dfu_target_call
 		new_target = &dfu_target_suit;
 	}
 #endif
+#ifdef CONFIG_DFU_TARGET_CUSTOM
+	if (img_type == DFU_TARGET_IMAGE_TYPE_CUSTOM) {
+		new_target = &dfu_target_custom;
+	}
+#endif
 
 	if (new_target == NULL) {
 		LOG_ERR("Unknown image type");