[nrf noup] zephyr: Keep boot preference after reboot

fixup! [nrf noup] bootloader: Add bootloader requests

Add a possibility to keep the boot preference value between device
resets.

Ref: NCSDK-35479

Signed-off-by: Tomasz Chyrowicz <[email protected]>

Author: tomchy

boot/bootutil/zephyr/CMakeLists.txt

@@ -17,9 +17,15 @@ zephyr_library_sources(
   ../src/bootutil_public.c
     )
 if(CONFIG_NRF_MCUBOOT_BOOT_REQUEST)
+  zephyr_library_sources(
+    src/boot_request.c
+  )
   zephyr_library_sources_ifdef(CONFIG_NRF_MCUBOOT_BOOT_REQUEST_IMPL_RETENTION
     src/boot_request_retention.c
   )
+  zephyr_library_sources_ifdef(CONFIG_NRF_MCUBOOT_BOOT_REQUEST_IMPL_FLASH
+    src/boot_request_flash.c
+  )
 endif()
 
 # Sensitivity to the TEST_BOOT_IMAGE_ACCESS_HOOKS define is implemented for

boot/bootutil/zephyr/src/boot_request.c

@@ -0,0 +1,378 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Copyright (c) 2025 Nordic Semiconductor ASA
+ */
+#include <bootutil/boot_request.h>
+
+#include "bootutil/bootutil_log.h"
+#include "boot_request_mem.h"
+
+/** Special value of image number, indicating a request to the bootloader. */
+#define BOOT_REQUEST_IMG_BOOTLOADER 0xFF
+
+/** Additional memory used by the retention subsystem (2B - prefix, 4B - CRC).*/
+#define BOOT_REQUEST_ENTRY_METADATA_SIZE (2 + 4)
+
+/** Number of images supported by the bootloader requests. */
+#define BOOT_REQUEST_IMG_NUM 2
+
+BOOT_LOG_MODULE_REGISTER(bootloader_request);
+
+enum boot_request_type {
+	/** Invalid request. */
+	BOOT_REQUEST_INVALID = 0,
+
+	/** Request a change in the bootloader boot mode.
+	 *
+	 * @details Use @p boot_request_mode as argument.
+	 *          @p BOOT_REQUEST_IMG_BOOTLOADER as image number.
+	 *
+	 * @note Used to trigger recovery through i.e. retention sybsystem.
+	 */
+	BOOT_REQUEST_BOOT_MODE = 1,
+
+	/** Select the preferred image to be selected during boot or update.
+	 *
+	 * @details Use @p boot_request_slot_t as argument.
+	 *
+	 * @note Used in the Direct XIP mode.
+	 */
+	BOOT_REQUEST_IMG_PREFERENCE = 2,
+
+	/** Request a confirmation of an image.
+	 *
+	 * @details Use @p boot_request_slot_t as argument.
+	 *
+	 * @note Used if the code cannot modify the image trailer directly.
+	 */
+	BOOT_REQUEST_IMG_CONFIRM = 3,
+};
+
+/* Entries inside the boot request shared memory. */
+enum boot_request_entry {
+	BOOT_REQUEST_ENTRY_BOOT_MODE = 0,
+	BOOT_REQUEST_ENTRY_IMAGE_0_PREFERENCE = 1,
+	BOOT_REQUEST_ENTRY_IMAGE_0_CONFIRM = 2,
+	BOOT_REQUEST_ENTRY_IMAGE_1_PREFERENCE = 3,
+	BOOT_REQUEST_ENTRY_IMAGE_1_CONFIRM = 4,
+	BOOT_REQUEST_ENTRY_MAX = 5,
+};
+
+/* Assert that all requests will fit within the retention area. */
+BUILD_ASSERT((BOOT_REQUEST_ENTRY_METADATA_SIZE + BOOT_REQUEST_ENTRY_MAX * sizeof(uint8_t)) <
+		     DT_REG_SIZE_BY_IDX(DT_CHOSEN(nrf_bootloader_request), 0),
+	     "nrf,bootloader-request area is too small for bootloader request struct");
+
+enum boot_request_slot {
+	/** Unsupported value. */
+	BOOT_REQUEST_SLOT_INVALID = 0,
+	/** Primary slot. */
+	BOOT_REQUEST_SLOT_PRIMARY = 1,
+	/** Secondary slot. */
+	BOOT_REQUEST_SLOT_SECONDARY = 2,
+};
+
+/** Alias type for the image and number. */
+typedef uint8_t boot_request_slot_t;
+
+enum boot_request_mode {
+	/** Execute a regular boot logic. */
+	BOOT_REQUEST_MODE_REGULAR = 0,
+	/** Execute the recovery boot logic. */
+	BOOT_REQUEST_MODE_RECOVERY = 1,
+	/** Execute the firmware loader logic. */
+	BOOT_REQUEST_MODE_FIRMWARE_LOADER = 2,
+	/** Unsupported value. */
+	BOOT_REQUEST_MODE_INVALID = 0xFF,
+};
+
+/** Alias type for the image number. */
+typedef uint8_t boot_request_img_t;
+
+/**
+ * @brief Find an entry for a given request.
+ *
+ * @param[in]  type   Type of request.
+ * @param[in]  image  Image number. Use @p BOOT_REQUEST_IMG_BOOTLOADER for generic requests.
+ * @param[out] entry  Entry to use.
+ *
+ * @return 0 on success; nonzero on failure.
+ */
+static int boot_request_entry_find(enum boot_request_type type, boot_request_img_t image,
+				   size_t *entry)
+{
+	if (entry == NULL) {
+		return -EINVAL;
+	}
+
+	switch (type) {
+	case BOOT_REQUEST_BOOT_MODE:
+		*entry = BOOT_REQUEST_ENTRY_BOOT_MODE;
+		break;
+	case BOOT_REQUEST_IMG_PREFERENCE:
+		switch (image) {
+		case 0:
+			*entry = BOOT_REQUEST_ENTRY_IMAGE_0_PREFERENCE;
+			break;
+		case 1:
+			*entry = BOOT_REQUEST_ENTRY_IMAGE_1_PREFERENCE;
+			break;
+		default:
+			return -EINVAL;
+		}
+		break;
+	case BOOT_REQUEST_IMG_CONFIRM:
+		switch (image) {
+		case 0:
+			*entry = BOOT_REQUEST_ENTRY_IMAGE_0_CONFIRM;
+			break;
+		case 1:
+			*entry = BOOT_REQUEST_ENTRY_IMAGE_1_CONFIRM;
+			break;
+		default:
+			return -EINVAL;
+		}
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+int boot_request_init(void)
+{
+	return boot_request_mem_init();
+}
+
+int boot_request_clear(void)
+{
+#ifdef CONFIG_NRF_MCUBOOT_BOOT_REQUEST_PREFERENCE_KEEP
+	size_t nv_indexes[BOOT_REQUEST_IMG_NUM];
+	uint8_t image;
+
+	for (image = 0; image < BOOT_REQUEST_IMG_NUM; image++) {
+		if (boot_request_entry_find(BOOT_REQUEST_IMG_PREFERENCE, image,
+					    &nv_indexes[image]) != 0) {
+			return -EINVAL;
+		}
+	}
+
+	return boot_request_mem_selective_erase(nv_indexes, BOOT_REQUEST_IMG_NUM);
+#else
+	return boot_request_mem_selective_erase(NULL, 0);
+#endif
+}
+
+int boot_request_confirm_slot(uint8_t image, enum boot_slot slot)
+{
+	uint8_t value = BOOT_REQUEST_SLOT_INVALID;
+	size_t req_entry;
+	int ret;
+
+#ifdef CONFIG_NRF_MCUBOOT_BOOT_REQUEST_PREFERENCE_KEEP
+	if (!boot_request_mem_updateable()) {
+		BOOT_LOG_ERR("Unable to confirm slot - area not updateable.");
+		/* Cannot update area if it is corrupted. */
+		return -EIO;
+	}
+#endif
+
+	ret = boot_request_entry_find(BOOT_REQUEST_IMG_CONFIRM, image, &req_entry);
+	if (ret != 0) {
+		return ret;
+	}
+
+	switch (slot) {
+	case BOOT_SLOT_PRIMARY:
+		value = BOOT_REQUEST_SLOT_PRIMARY;
+		break;
+	case BOOT_SLOT_SECONDARY:
+		value = BOOT_REQUEST_SLOT_SECONDARY;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return boot_request_mem_write(req_entry * sizeof(value), &value);
+}
+
+bool boot_request_check_confirmed_slot(uint8_t image, enum boot_slot slot)
+{
+	uint8_t value = BOOT_REQUEST_SLOT_INVALID;
+	size_t req_entry;
+	int ret;
+
+	ret = boot_request_entry_find(BOOT_REQUEST_IMG_CONFIRM, image, &req_entry);
+	if (ret != 0) {
+		return false;
+	}
+
+	ret = boot_request_mem_read(req_entry * sizeof(uint8_t), &value);
+	if (ret != 0) {
+		return false;
+	}
+
+	switch (value) {
+	case BOOT_REQUEST_SLOT_PRIMARY:
+		return (slot == BOOT_SLOT_PRIMARY);
+	case BOOT_REQUEST_SLOT_SECONDARY:
+		return (slot == BOOT_SLOT_SECONDARY);
+	default:
+		break;
+	}
+
+	return false;
+}
+
+int boot_request_set_preferred_slot(uint8_t image, enum boot_slot slot)
+{
+	uint8_t value = BOOT_REQUEST_SLOT_INVALID;
+	size_t req_entry;
+	int ret;
+
+#ifdef CONFIG_NRF_MCUBOOT_BOOT_REQUEST_PREFERENCE_KEEP
+	if (!boot_request_mem_updateable()) {
+		BOOT_LOG_ERR("Unable to select slot - area not updateable.");
+		/* Cannot update area if it is corrupted. */
+		return -EIO;
+	}
+#endif
+
+	ret = boot_request_entry_find(BOOT_REQUEST_IMG_PREFERENCE, image, &req_entry);
+	if (ret != 0) {
+		return ret;
+	}
+
+	switch (slot) {
+	case BOOT_SLOT_PRIMARY:
+		value = BOOT_REQUEST_SLOT_PRIMARY;
+		break;
+	case BOOT_SLOT_SECONDARY:
+		value = BOOT_REQUEST_SLOT_SECONDARY;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return boot_request_mem_write(req_entry * sizeof(value), &value);
+}
+
+enum boot_slot boot_request_get_preferred_slot(uint8_t image)
+{
+	uint8_t value = BOOT_REQUEST_SLOT_INVALID;
+	size_t req_entry;
+	int ret;
+
+	ret = boot_request_entry_find(BOOT_REQUEST_IMG_PREFERENCE, image, &req_entry);
+	if (ret != 0) {
+		return BOOT_SLOT_NONE;
+	}
+
+	ret = boot_request_mem_read(req_entry * sizeof(uint8_t), &value);
+	if (ret != 0) {
+		return BOOT_SLOT_NONE;
+	}
+
+	switch (value) {
+	case BOOT_REQUEST_SLOT_PRIMARY:
+		return BOOT_SLOT_PRIMARY;
+	case BOOT_REQUEST_SLOT_SECONDARY:
+		return BOOT_SLOT_SECONDARY;
+	default:
+		break;
+	}
+
+	return BOOT_SLOT_NONE;
+}
+
+int boot_request_enter_recovery(void)
+{
+	uint8_t value = BOOT_REQUEST_MODE_RECOVERY;
+	size_t req_entry;
+	int ret;
+
+#ifdef CONFIG_NRF_MCUBOOT_BOOT_REQUEST_PREFERENCE_KEEP
+	if (!boot_request_mem_updateable()) {
+		BOOT_LOG_ERR("Unable to enter recovery - area not updateable.");
+		/* Cannot update area if it is corrupted. */
+		return -EIO;
+	}
+#endif
+
+	ret = boot_request_entry_find(BOOT_REQUEST_BOOT_MODE, BOOT_REQUEST_IMG_BOOTLOADER,
+				      &req_entry);
+	if (ret != 0) {
+		return ret;
+	}
+
+	return boot_request_mem_write(req_entry * sizeof(value), &value);
+}
+
+#ifdef CONFIG_NRF_BOOT_SERIAL_BOOT_REQ
+bool boot_request_detect_recovery(void)
+{
+	uint8_t value = BOOT_REQUEST_MODE_INVALID;
+	size_t req_entry;
+	int ret;
+
+	ret = boot_request_entry_find(BOOT_REQUEST_BOOT_MODE, BOOT_REQUEST_IMG_BOOTLOADER,
+				      &req_entry);
+	if (ret != 0) {
+		return false;
+	}
+
+	ret = boot_request_mem_read(req_entry * sizeof(uint8_t), &value);
+	if ((ret == 0) && (value == BOOT_REQUEST_MODE_RECOVERY)) {
+		return true;
+	}
+
+	return false;
+}
+#endif /* CONFIG_NRF_BOOT_SERIAL_BOOT_REQ */
+
+int boot_request_enter_firmware_loader(void)
+{
+	uint8_t value = BOOT_REQUEST_MODE_FIRMWARE_LOADER;
+	size_t req_entry;
+	int ret;
+
+#ifdef CONFIG_NRF_MCUBOOT_BOOT_REQUEST_PREFERENCE_KEEP
+	if (!boot_request_mem_updateable()) {
+		BOOT_LOG_ERR("Unable to enter FW loader - area not updateable.");
+		/* Cannot update area if it is corrupted. */
+		return -EIO;
+	}
+#endif
+
+	ret = boot_request_entry_find(BOOT_REQUEST_BOOT_MODE, BOOT_REQUEST_IMG_BOOTLOADER,
+				      &req_entry);
+	if (ret != 0) {
+		return ret;
+	}
+
+	return boot_request_mem_write(req_entry * sizeof(value), &value);
+}
+
+#ifdef CONFIG_NRF_BOOT_FIRMWARE_LOADER_BOOT_REQ
+bool boot_request_detect_firmware_loader(void)
+{
+	uint8_t value = BOOT_REQUEST_MODE_INVALID;
+	size_t req_entry;
+	int ret;
+
+	ret = boot_request_entry_find(BOOT_REQUEST_BOOT_MODE, BOOT_REQUEST_IMG_BOOTLOADER,
+				      &req_entry);
+	if (ret != 0) {
+		return false;
+	}
+
+	ret = boot_request_mem_read(req_entry * sizeof(uint8_t), &value);
+	if ((ret == 0) && (value == BOOT_REQUEST_MODE_FIRMWARE_LOADER)) {
+		return true;
+	}
+
+	return false;
+}
+#endif /* CONFIG_NRF_BOOT_FIRMWARE_LOADER_BOOT_REQ */