WIP: MCUBoot Readme

README.md

@@ -1,8 +1,15 @@
-# UTAT Firmware Development Environment
+# UTAT Firmware Development MCUBoot POC
 
-My firmware development environment for the University of Toronto Aerospace Team 
+Documentation of the steps taken to implement MCUBoot.
 
-https://docs.zephyrproject.org/latest/develop/getting_started/index.html
+## Environnment config
+Use the environment written in flake.nix by running `nix develop`
+
+
+## Set up Zephyr
+Zephyr is the RTOS that runs on the Nucleo G431RB development board I'm using.
+
+[Getting started with Zephyr](https://docs.zephyrproject.org/latest/develop/getting_started/index.html)
 
 ```sh
 west init zephyrproject
@@ -13,25 +20,85 @@ west zephyr-export
 
 cd zepyhr
 west sdk install
+```
 
+## MCUBoot POC Implementation
+
+MCUBoot is a bootloader for Zephyr, which allows multiple firmwares to exist on a board. MCUBoot can dynamically switch which firmware is active. This is useful in the event of one firmware failing.
+
+[Abstract MCUBoot Guide](https://docs.mcuboot.com/readme-zephyr.html)
+
+```sh
 west build -p always -b nucleo_g431rb samples/basic/blinky
 west flash --runner pyocd # had to su root first to run this (after running nix develop)
+```
 
-# MCUBoot
-cd ~/utat-dev/zephyrproject
-# Configure the DTS for partition sizes: https://docs.zephyrproject.org/latest/build/dts/intro-scope-purpose.html
-# https://docs.zephyrproject.org/latest/build/dts/api/bindings/mtd/fixed-partitions.html
-nvim "zephyr/boards/st/nucleo_g431rb/nucleo_g431rb.dts"
 
+## Configure partition sizes
+
+The devicetree specification file declares the hardware configuration. The flash storage needs three partitions, one for boot, and two for the two firmwares it will hold.
+
+[DeviceTree Specification documentation](https://docs.zephyrproject.org/latest/build/dts/intro-scope-purpose.html)
+
+[Partitioning examples](https://docs.zephyrproject.org/latest/build/dts/api/bindings/mtd/fixed-partitions.html)
+
+The board I'm using has its DeviceTree Specification in `zephyr/boards/st/nucleo_g431rb/nucleo_g431rb.dts`
+
+I created a partition for MCUBoot, two firmware slots, and additional storage in the flash storage.
+
+```c
+&flash0 {
+	partitions {
+		#address-cells = <1>;
+		#size-cells = <1>;
+		ranges;
+
+		boot_partition: partition@0 {
+			compatible = "zephyr,mapped-partition";
+			label = "mcuboot";
+			reg = <0x00000000 0x00008000>;
+		};
+
+		slot0_partition: partition@8000 {
+			compatible = "zephyr,mapped-partition";
+			label = "image-0";
+			reg = <0x00008000 0x00010000>;
+		};
+
+		slot1_partition: partition@10000 {
+			compatible = "zephyr,mapped-partition";
+			label = "image-1";
+			reg = <0x00010000 0x0018000>;
+		};
+
+		storage_partition: partition@18000 {
+			compatible = "zephyr,mapped-partition";
+			label = "storage";
+			reg = <0x00018000 0x00020000>;
+		};
+	};
+};
+
+```
+
+## Try to build MCUBoot
+```sh
+west build -p always -b nucleo_g431rb bootloader/mcuboot/boot/zephyr
+```
+
+
+
+old below
+```
 # Create a private key: https://docs.mcuboot.com/readme-zephyr.html
-./scripts/imgtool.py keygen -k mykey.pem -t rsa-2048
+python ./bootloader/mcuboot/scripts/imgtool.py keygen -k private.pem -t rsa-2048
 
 # Create its public key
-openssl rsa -in mykey.pem -pubout > pubkey.pem
+openssl rsa -in private.pem -pubout > public.pem
 
 # Set up signing: https://docs.mcuboot.com/readme-zephyr.html
 # ./bootloader/mcuboot/samples/zephyr/Makefile
-python scripts/imgtool.py sign \
+python bootloader/mcuboot/scripts/imgtool.py sign \
     --key mykey.pem \
     --header-size 0x200 \
     --align 8 \
@@ -44,7 +111,7 @@ python scripts/imgtool.py sign \
 echo "
 
 # Set the key file
-CONFIG_BOOT_SIGNATURE_KEY_FILE=pubkey.pem" >> "./zephyr/boards/st/nucleo_g431rb/nucleo_g431rb_defconfig"
+CONFIG_BOOT_SIGNATURE_KEY_FILE=public.pem" >> "./zephyr/boards/st/nucleo_g431rb/nucleo_g431rb_defconfig"