doc: design: Add updated information on data sharing
Adds additional information on the new BOOTINFO data sharing
functionality
Signed-off-by: Jamie McCrae <jamie.mccrae@nordicsemi.no>
diff --git a/docs/design.md b/docs/design.md
index 162927a..27262bd 100755
--- a/docs/design.md
+++ b/docs/design.md
@@ -1360,7 +1360,12 @@
this, the target must provide a definition for the `boot_save_shared_data()`
function which is declared in `boot/bootutil/include/bootutil/boot_record.h`.
The `boot_add_data_to_shared_area()` function can be used for adding new TLV
-entries to the shared data area.
+entries to the shared data area. Alternatively, setting the
+`MCUBOOT_DATA_SHARING_BOOTINFO` option will provide a default function for
+this which saves information such as the maximum application size, bootloader
+version (if available), running slot number, if recovery is part of MCUboot
+and the signature type. Details of the TLVs for this information can be found
+in `boot/bootutil/include/bootutil/boot_status.h` with `BLINFO_` prefixes.
## [Testing in CI](#testing-in-ci)