zephyr: Add shared data support
Adds the ability to share mcuboot configuration with the
application using Zephyr's retention subsystem.
Signed-off-by: Jamie McCrae <jamie.mccrae@nordicsemi.no>
diff --git a/boot/zephyr/shared_data.c b/boot/zephyr/shared_data.c
new file mode 100644
index 0000000..5554a7e
--- /dev/null
+++ b/boot/zephyr/shared_data.c
@@ -0,0 +1,124 @@
+/*
+ * Copyright (c) 2023, Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <assert.h>
+#include <zephyr/kernel.h>
+#include <zephyr/devicetree.h>
+#include <zephyr/retention/retention.h>
+#include <zephyr/logging/log.h>
+#include <bootutil/boot_record.h>
+#include <bootutil/boot_status.h>
+#include <../../bootutil/src/bootutil_priv.h>
+
+#define SHARED_MEMORY_MIN_SIZE 8
+
+LOG_MODULE_REGISTER(bootloader_info, CONFIG_RETENTION_LOG_LEVEL);
+
+static bool shared_memory_init_done = false;
+static uint16_t shared_data_size = SHARED_DATA_HEADER_SIZE;
+static ssize_t shared_data_max_size = 0;
+static const struct device *bootloader_info_dev =
+ DEVICE_DT_GET(DT_CHOSEN(zephyr_bootloader_info));
+
+BUILD_ASSERT(SHARED_MEMORY_MIN_SIZE < \
+ DT_REG_SIZE_BY_IDX(DT_CHOSEN(zephyr_bootloader_info), 0), \
+ "zephyr,bootloader-info area is too small for bootloader information struct");
+
+int boot_add_data_to_shared_area(uint8_t major_type,
+ uint16_t minor_type,
+ size_t size,
+ const uint8_t *data)
+{
+ struct shared_data_tlv_header header = {
+ .tlv_magic = SHARED_DATA_TLV_INFO_MAGIC,
+ .tlv_tot_len = shared_data_size,
+ };
+ struct shared_data_tlv_entry tlv_entry = {0};
+ uint16_t boot_data_size;
+ uintptr_t tlv_end, offset;
+ int rc;
+
+ if (data == NULL) {
+ return SHARED_MEMORY_GEN_ERROR;
+ }
+
+ /* Check whether first time to call this function. If does then initialise
+ * shared data area.
+ */
+ if (!shared_memory_init_done) {
+ retention_clear(bootloader_info_dev);
+ shared_data_max_size = retention_size(bootloader_info_dev);
+ shared_memory_init_done = true;
+ }
+
+ /* Check whether TLV entry is already added.
+ * Get the boundaries of TLV section
+ */
+ tlv_end = shared_data_size;
+ offset = SHARED_DATA_HEADER_SIZE;
+
+ /* Iterates over the TLV section looks for the same entry if found then
+ * returns with error: SHARED_MEMORY_OVERWRITE
+ */
+ while (offset < tlv_end) {
+ /* Create local copy to avoid unaligned access */
+ rc = retention_read(bootloader_info_dev, offset, (void *)&tlv_entry,
+ SHARED_DATA_ENTRY_HEADER_SIZE);
+
+ if (rc) {
+ return SHARED_MEMORY_READ_ERROR;
+ }
+
+ if (GET_MAJOR(tlv_entry.tlv_type) == major_type &&
+ GET_MINOR(tlv_entry.tlv_type) == minor_type) {
+ return SHARED_MEMORY_OVERWRITE;
+ }
+
+ offset += SHARED_DATA_ENTRY_SIZE(tlv_entry.tlv_len);
+ }
+
+ /* Add TLV entry */
+ tlv_entry.tlv_type = SET_TLV_TYPE(major_type, minor_type);
+ tlv_entry.tlv_len = size;
+
+ if (!boot_u16_safe_add(&boot_data_size, shared_data_size,
+ SHARED_DATA_ENTRY_SIZE(size))) {
+ return SHARED_MEMORY_GEN_ERROR;
+ }
+
+ /* Verify overflow of shared area */
+ if (boot_data_size > shared_data_max_size) {
+ return SHARED_MEMORY_OVERFLOW;
+ }
+
+ offset = shared_data_size;
+ rc = retention_write(bootloader_info_dev, offset, (void*)&tlv_entry,
+ SHARED_DATA_ENTRY_HEADER_SIZE);
+ if (rc) {
+ LOG_ERR("Shared data TLV header write failed: %d", rc);
+ return SHARED_MEMORY_WRITE_ERROR;
+ }
+
+ offset += SHARED_DATA_ENTRY_HEADER_SIZE;
+ rc = retention_write(bootloader_info_dev, offset, data, size);
+
+ if (rc) {
+ LOG_ERR("Shared data TLV data write failed: %d", rc);
+ return SHARED_MEMORY_WRITE_ERROR;
+ }
+
+ shared_data_size += SHARED_DATA_ENTRY_SIZE(size);
+ header.tlv_tot_len = shared_data_size;
+
+ rc = retention_write(bootloader_info_dev, 0, (void *)&header,
+ sizeof(header));
+
+ if (rc) {
+ return SHARED_MEMORY_WRITE_ERROR;
+ }
+
+ return SHARED_MEMORY_OK;
+}