# RDKB on RPI4

# REF
https://wiki.rdkcentral.com/display/CMF/RDKB_2023q2_dunfell
https://wiki.rdkcentral.com/display/RDK/RDK-B+%28Raspberry+Pi%29+Build+and+Setup+Manual+-+Router+Profile
https://wiki.rdkcentral.com/display/ASP/Cellular+Manager+-+Reference+set+up

# SDK Source Code
Download with an authenticated user of RDK Central

repo init -u https://code.rdkcentral.com/r/manifests -m rdkb-extsrc.xml -b rdkb-2023q2-dunfell
repo sync -j `nproc` --no-clone-bundle --no-tags

Or download the packaged SDK, which is temporarily placed in `/opt/build_data/rdkb_rpi.tar.bz2` on the AMAROK server.

# Start to build image
## Build commands for raspberry 4B 64bit

MACHINE=raspberrypi4-64-rdk-broadband source meta-cmf-raspberrypi/setup-environment
bitbake rdk-generic-broadband-image

# Fix compiling errors
If you encounter a building error about the `/tmp/dhcp_relay.conf`, you could comment out the following line and rebuild it again.

~/rdkb_rpi/build-raspberrypi4-64-rdk-broadband/tmp/work/aarch64-rdk-linux/opensync/git-r0/git/core//./src/lib/dhcp_relay/ut/unit.mk
...
#${Q} cp $< $@
...

If the `JAVA_HOME` can not be detected, disable the package `zilker` that requires it.
The `zilker` is included in the image by the the following `bbappend` file, we could disable it by removing it from the `RDEPENDS_packagegroup-rdk-oss-broadband_append` variable.

~/rdkb_rpi/meta-cmf-raspberrypi/recipes-core/packagegroups/packagegroup-rdk-oss-broadband.bbappend
RDEPENDS_packagegroup-rdk-oss-broadband_append = " \
...
- zilker-sdk \
...
"

# Flash Image into SD card
The final image is located in the `DEPLOY_DIR`, and the image file name is `rdk-generic-broadband-image-raspberrypi4-rdk-broadband.wic.bz2` which is a symbolic link to `rdkb-generic-broadband-image_rdk-next_2023xxxxxxxxxx.rootfs.wic.bz2`.

~/rdkb_rpi/build-raspberrypi4-rdk-broadband/tmp/deploy/images/raspberrypi4-rdk-broadband$ ls | grep wic
rdkb-generic-broadband-image_rdk-next_20231003101038.rootfs.wic.bmap
rdkb-generic-broadband-image_rdk-next_20231003101038.rootfs.wic.bz2
rdk-generic-broadband-image-raspberrypi4-rdk-broadband.wic.bmap
rdk-generic-broadband-image-raspberrypi4-rdk-broadband.wic.bz2
	  
~/rdkb_rpi/build-raspberrypi4-rdk-broadband/tmp/deploy/images/raspberrypi4-rdk-broadband$ ls -al rdk-generic-broadband-image-raspberrypi4-64-rdk-broadband.wic.bz2
lrwxrwxrwx 2 jeff_shiu jeff_shiu 78 Oct 26 20:43 rdk-generic-broadband-image-raspberrypi4-64-rdk-broadband.wic.bz2 -> rdkb-generic-broadband-image_rdkb-2023q2-dunfell_20231026123545.rootfs.wic.bz2

Before flashing it into the SD card, we have to decompress it to get the raw image, then we could use `Raspberry Pi Imager` to flash the image.

~/rdkb_rpi/build-raspberrypi4-rdk-broadband/tmp/deploy/images/raspberrypi4-rdk-broadband$ bunzip2 -dkf rdk-generic-broadband-image-raspberrypi4-64-rdk-broadband.wic.bz2

The `Raspberry Pi Imager` can be downloaded from the link `https://downloads.raspberrypi.org/imager/imager_latest.exe`.
This tool can help us flash any image to SD card by selecting "Use the custom image", so we use it to flash the RDKB image.

# Serial Console (UART) on RPI4
The following figure is the GPIO pin map of RPI4. We could know that `GPIO 14` is for `TX` and `GPIO 15` is for `RX`. Typically, the color of the RX wire is white and the TX is green, so we need to plug the white wire into `GPIO 14` and the green wire into `GPIO 15`.