{{ImportantMessage|text=As the structure of the BELK/BXELK is based on several tools, it is strongly recommended the reading of [[Logical_structure_of_Bora_and_BoraX_Embedded_Linux_Kits_(BORA_SOM/BELK-L/BXELK)General/Logical_structure_of_BELK|this document]] firstto get an overview.

{{ImportantMessage|text=As the BELK/BXELK provides one kit is based on Yocto, the implementation of the MVM follows the approach described [[Managed_Virtual_Machine_(or moreMVM) pre#Yocto-built root file systembased_Linux_distribution|here]]. As such, that can be used during the evaluation/development phase since it provides a relatively rich set reading of packages for working with the BORA platform. This root file system [[Managed_Virtual_Machine_(MVM)#Yocto-based_Linux_distribution|this section]] is located here: <code>/home/dvdk/<target_name>/rfs/<kit_name></code>highly recommended.}}

==How to build the Yocto BSP images including the U-Boot binary file, the Linux kernel image, and the target root file system image=={{ImportantMessage|text=The following procedure requires the access instructions described by this document apply to the DAVE Embedded Systemsfollowing kits:*''' git repositoriesBELK 4.0. The access to such repositories is granted to development kit0 or newer'''*'''s owners onlyBXELK 2. Please refer to [[Accessing_DAVE_Embedded_Systems_restricted_git_repositories|this page]] for detailed instructions on how to get it0.0 or newer'''.}}

The components listed in the table above can be kept in sync and up to date with DAVE Embedded Systems' repositories.Once the git account has been enabled, the developer can:*clone the repository with the <code>git clone <git_remote_repository></code> command *synchronize a source tree entering the repository directory and launching the <code>git fetch origin</code> command.Please note that git fetch doesn't merge the commits on the current branch. To do that, the developer should run the <code>git merge<section begin=BELK/code> command or replace the ''fetch-merge'' process with a single <code>git pull</code> command. Please note that the recommended method is the ''fetch-merge'' process. For further information on Git, please refer to the official Git Documentation (http://git-scm.com/documentation).

!Kit version<br>BELK<br>BXELK|+Build targets!Image name!Build commandsName!PathDescription

|rowspan="3"|<br>4.0.0<br>2.0.0|<code>boradave-image</code>-devel|<pre>dvdk@dvdk-vm:~/belk$ curl http://commondatastorage.googleapis.com/git-repo-downloads/repo > repodvdk@dvdk-vm:~/belk$ chmod a+x repodvdk@dvdk-vm:~/belk$ ./repo init -u git@git.dave.eu:bora/bora-bsp.git -b bora-mortydvdk@dvdk-vm:~/belk$ ./repo syncdvdk@dvdk-vm:~/belk$ source bora-bsp-init-env.shdvdk@dvdk-vm:~/belk/build$ bitbake bora-This image</pre>|<code>/home/dvdk/bora/rfs/belk-4.0.0<include tools for development/code>debugging

|dave-image-networking| In addition <code>dave-image-devel</code>, this image provides several networking tools|} As known, in addition to a bootloader and the o.s. kernel, an embedded Linux system needs a root file system to operate. The root file system must contain everything needed to support the Linux system (applications, settings, data, etc.). The root file system is the file system that is contained on the same partition on which the root directory is located. The Linux kernel, at the end of its startup stage, mounts the root file system on the configured root device and finally launches the <code>/sbin/init</code>, the first user space process and "father" of all the other processes.For more information on the Linux filesystem, please refer to http://www.thegeekstuff.com/2010/09/linux-file-system-structure/. BELK/BXELK provides one (or more) pre-built root file system, that can be used during the evaluation/development/deployment cycle. For instance, the root file system included in the <code>bora-image-devel</code> image is suited for the development phase, since it provides a relatively rich set of packages including tools and libraries used to debug the application code. The pre-built root file systems are located here: <code>/home/dvdk/<target_name>/rfs/<kit_name></code>. Besides the pre-built root file systems, BELK/BXELK also provides a rich repository containing pre-built applications and libraries. These packages can be easily installed on the target by using the <code>smart</code> tool. Please refer to [[BORA_SOM/BELK-L/Development/Advanced_use_of_Yocto_build_system#Using_pre-built_package_archive|this section]] for more details. To generate the supported root file systems, the build of the Yocto BSP has to be run. The output of this process is an image containing the U-Boot binary file, the Linux kernel image, and the selected root file system image. The following sections describe in detail how to execute this operation. For more general information regarding the Yocto build system, please refer the [[:Category:Yocto|dedicated category page]]. ===How to build the Yocto BSP images including the U-Boot binary file, the Linux kernel image, and the target root file system image==={{ImportantMessage|text=The following procedure requires the access to the DAVE Embedded Systems' git repositories. The access to such repositories is granted to development kit's owners only. Please refer to [[Accessing_DAVE_Embedded_Systems_restricted_git_repositories|this page]] for detailed instructions on how to get it.}}  {{ImportantMessage|text=This process requires a lot of hardware resources in terms of disk storage, RAM, and processing power. For this reason, it also is recommended to consider the use of a physical machine. For more details on this topic, please refer to [[BORA_SOM/BELK-L/Development/Advanced_use_of_Yocto_build_system|this document]] which talks about the advanced use of the Yocto build system.}} ==== Initialize the build environment ====Before running the build, the environment must be initialized properly. BELK/BXELK Yocto BSP uses [https://code.google.com/p/git-repo/ git-repo] tool to fetch all the required git repositories. To install it, please use the following commands:<preclass="workstation-terminal">dvdk@dvdk-vm:~/belk$ curl http://commondatastorage.googleapis.com/git-repo-downloads/repo -1 > repo

 ===== unauthenticated git protocol error ====={{ImportantMessage|<code>/home/dvdk/bora/rfs/belktext=Since March 15th, 2022, GitHub stopped accepting DSA keys. RSA keys uploaded after Nov 2, 2021 will work only with SHA-42 signatures.0The deprecated MACs, ciphers, and unencrypted Git protocol are permanently disabled.0</codebr>For more details on this topic, please refer to [[MISC-TN-015:_Yocto_and_git_protocol_error|-this Technical Note]].}}|<code>bora-image-networking</code>|<pre>==== Running the build ====dvdk@dvdkPlease note that even the basic root file system requires a few hours to build on a mid/hi range desktop (4-6 cores, 8-vm:~/belk$ curl http://commondatastorage12 GiB RAM) also depending on your Internet connection speed (all sources are fetched from the network). Nearly 20GiB of disk space is required for the build.googleapisThe process may be slowed down significantly since the performances of a virtual machine are reduced if compared to the physical hardware.com/git-repo-downloads/repo > repoThus, it's recommended to check the hardware capabilities of the host system and, when building with Yocto is required, to consider the following options: dvdk@dvdk-vm:~/belk$ chmod * Migrating the build system to a+x repophysical machinedvdk@dvdk-vm:~/belk$ ./repo init -u git@git* Assuming that the host system has the required resources, extending the hardware capabilities of the default MVM (e.daveg.eu:bora/bora-bspadding more cores and disk space).git -b bora-mortydvdk@dvdk-vmOnce completed the initialization phase, developers can launch the Yocto image build process with the following commands:~/belk$ ./repo syncdvdk@dvdk<pre class="workstation-vm:~/belk$ source bora-bsp-init-env.shterminal">dvdk@dvdk-vm:~/belk/build$ bitbake bora<target-image-networkingname>

|Where <code>/home/dvdk/bora/rfs/belk<target-image-4.0.0name></code>is one of the images listed in [[#Quick reference|-|}here]].

The following table lists ====Generating the pre-built Yocto SDKs included ====After creating an image as described in the MVM. These SDKs are associated with previous version, the corresponding SDK can be generated by issuing the root file system images mentioned above.following command:{| <pre class="wikitable" border="1"!Kit version<br>BELK<br>BXELK!SDK name!Build commands!Path|workstation-|rowspan=terminal"3"|<br>4.0.0<br>2.0.0|bitbake <code>boratarget-image</code-name>|<pre>bitbake bora-image -c populate-sdk

|Again, replace <code>/home/dvdk/bora/sdk/belk<target-4.0.0/sysroots/cortexa9hfimage-neon-xilinx-linux-gnueabiname></code>with one of the images listed in [[#Quick reference|here]]. === Building additional packages ===|-|To build additional packages the user must first enter the directory where the <code>bora-imagebsp-init-develenv.sh</code>is placed and source it |<preclass="workstation-terminal">bitbake dvdk@dvdk-vm:~/belk$ source bora-imagebsp-devel init-c populateenv.shdvdk@dvdk-sdkvm:~/belk/build$

|<code>And then can run any of the [http:/home/dvdkwww.yoctoproject.org/boradocs/sdklatest/belkmega-4.0.0manual/sysroots/cortexa9hfmega-neonmanual.html#usingpoky-xilinx-linux-gnueabi</code>|components-bitbake bitbake] command.|<code>bora-image-networking</code>|<preclass="workstation-terminal">dvdk@dvdk-vm:~/belk/build$ bitbake bora-image-networking -c populate-sdkmemtester

About C<pre class="workstation-terminal">dvdk@dvdk-vm:~/C++ application development and debugging, please refer to [[Debugging_with_Eclipse_(MVM)|this page]]belk/build$ ls -l tmp/deploy/rpm/cortexa9hf_neon/memtester*-rw-r--r-- 1 dvdk dvdk 10692 Sep 12 16:05 tmp/deploy/rpm/cortexa9hf_neon/memtester-4.3.0-r0.cortexa9hf_neon.rpm-rw-r--r-- 1 dvdk dvdk 27693 Sep 12 16:05 tmp/deploy/rpm/cortexa9hf_neon/memtester-dbg-4.3.0-r0.cortexa9hf_neon.rpm-rw-r--r-- 1 dvdk dvdk 2872 Sep 12 16:05 tmp/deploy/rpm/cortexa9hf_neon/memtester-dev-4.3.0-r0.cortexa9hf_neon.rpm-rw-r--r-- 1 dvdk dvdk 5903 Sep 12 16:05 tmp/deploy/rpm/cortexa9hf_neon/memtester-doc-4.3.0-r0.cortexa9hf_neon.rpm</pre><section end=BELK/>