wiki:venice/bsp

Version 18 (modified by Tim Harvey, 3 years ago) ( diff )

updated cross-compile example to use static and explain how to use shared

  1. Venice Board Support Package (BSP)
    1. BSP Pre-Built Firmware Images
    2. BSP Source Code
    3. Building the BSP from source
      1. Working with the repo tool
        1. Updating to the latest code (repo sync)
        2. Showing diffs for all projects (repo diff)
        3. Using the latest version
      2. Modifying the stand-alone Linux Kernel
    4. Toolchain
      1. Buildroot based toolchain
      2. External toolchain
      3. Cross compile examples
  2. SSH using Ubuntu

Venice Board Support Package (BSP)

Gateworks provides a Board Support Package for Venice which provides source code and an easy mechanism to build different images, including a minimal Buildroot based distro as well as an Ubuntu based distro.

The Gateworks BSP is the easiest comprehensive software process because it contains everything. If a deep dive, expert path is desired, each piece of the BSP (boot firmware, rootfs, kernel) can all be built separately.

BSP Pre-Built Firmware Images

Pre-built firmware images can be found on ​http://dev.gateworks.com/venice.

A sampling includes:

  • Entire Board Software (recommended), including boot firmware, bootloader, OS, kernel, etc:
    • ​Venice Images - Compressed Disk Image containing Firmware and kernel and OS ( .img.gz files )
      • Ubuntu version details are available here
  • Venice GSC
  • Only Boot Firmware
    • ​venice-imx8mm-flash.bin - Boot Firmware for updating from U-Boot or Linux (everything up to and including the bootloader except for partition table and U-Boot env) (see venice/boot for details)
    • ​venice-imx8mm_u-boot_spl.bin - Boot Firmware for updating via JTAG (everything up to and including the bootloader except for partition table and U-Boot env) (see venice/boot for details)
    • ​firmware-venice-.bin - Boot Firmware for updating via JTAG (everything up to and including the bootloader including partition table and U-Boot env) (see venice/boot for details)
  • Only Venice Kernel

Installation instructions:

BSP Source Code

Source code for the firmware, bootloader and kernel are hosted at GitHub. We highly recommend you create a GitHub account and 'Watch' these repositories to keep abreast of important feature additions, bugfixes, and firmware-releases. You can configure your GitHub account to e-mail you when changes are made to repositories ​here.

The following GitHub repos are used for Venice:

Building the BSP from source

Below are instructions for building the entire BSP, which includes all of the bootloader components, Linux kernel, and Ubuntu. Pre-built images are available above.

The Gateworks Venice Board Support Package uses the Google ​git-repo tool to manage multiple code repositories.

The following pre-requisites are needed to build the Venice BSP:

  • Linux Development host (desktop or laptop computer) (Ubuntu 16.04 is used by Gateworks and tested)
  • Python 2.x (required by the 'repo' tool)
  • Git (used for source code repositories)
  • repo (used to manage multiple git repos)

NOTE: Building images requires root privileges

Installing pre-requisites: 

sudo apt-get install build-essential git python libssl-dev ncurses-dev kmod bison flex device-tree-compiler -y

Install the latest version of repo (Do not rely on Ubuntu apt package being up to date): 

sudo wget https://storage.googleapis.com/git-repo-downloads/repo -O /usr/local/bin/repo
sudo chmod a+rx /usr/local/bin/repo

To obtain the code:

  1. Initialize repo (fetch the repo manifest) 
    mkdir $HOME/venice
cd $HOME/venice
repo init -u https://github.com/Gateworks/manifest-venice.git
  2. Sync repositories (repeat this when you want to fetch the latest code updates) 
    repo sync
    • This will fetch/update the source repos described above. The first time it can take several minutes depending on your Internet connection and will take approximately ~3GB of disk space
  3. Setup build environment (*repeat this each time you open a shell*) 
    source setup-environment
  4. Build desired software target as defined below. For example: 
    make -j8 ubuntu-image # build focal-venice.img.gz

Working with the repo tool

The repo tool unifies Git repositories into a single project by specifying Git repos and directories they exist in. The tool was created for the Android project as Android is comprised of hundreds of repos however it has since been used by many projects that benefit from its git repo management tool.

See:

Updating to the latest code (repo sync)

When working with the repo tool you can update to the latest code using the repo sync command: 

$ repo sync
Fetching: 100% (8/8), done in 5.258s
Garbage collecting: 100% (8/8), done in 0.188s
repo sync has finished successfully.

The repo tool works off of a manifest file in .repo/manifests/default.xml which specifies the various projects, what repo they are in, and where they are checked out in your directory structure. If a branch has changed, a project added, or a project removed the manifest file will be updated when you run repo sync then it will update the various project repos. If a branch has changed to something new you can encounter an error such as: 

$ repo sync
remote: Enumerating objects: 5, done.
remote: Counting objects: 100% (5/5), done.
remote: Compressing objects: 100% (1/1), done.
remote: Total 3 (delta 1), reused 3 (delta 1), pack-reused 0
Unpacking objects: 100% (3/3), done.
project .repo/manifests/
Updating 5c981dac1797..0b0055e7445e
Fast-forward

error: in `sync`: revision v5.10.76-venice in Gateworks/linux-venice not found

This specific error is saying that the 'v5.10.76-venice' revision (or branch) is not in the current working copy of the repo. To resolve this you need to do a git remote update for that project. You can also use repo foreach to update all projects: 

repo forall -c git remote update # update all projects
git -C linux remote update # update just the project in the linux path

Showing diffs for all projects (repo diff)

You can show all the diffs for each project using repo diff

Using the latest version

The repo tool is updated frequently. While it is rarely necessary to have the latest version it will inform you if there is an update and how to install that update in the current working directory: 

$ repo sync

... A new version of repo (2.17) is available.
... You should upgrade soon:
    cp /usr/src/venice/bsp/.repo/repo/repo /home/user/bin/repo
...

To update the repo tool just copy the file as mentioned above: 

cp .repo/repo/repo $HOME/bin/repo

Modifying the stand-alone Linux Kernel

The Gateworks Venice BSP instructions above create an environment for building the Linux kernel among other targets.

Some additional instructions for common actions (make sure you have already installed the BSP and setup your shell environment as specified above):

  • Make standard Gateworks Venice kernel with Gateworks venice_defconfig 
    make linux # first build the kernel with the standard venice_defconfig
  • Modify Kernel configuration (enabling modules etc): 
    make -C linux menuconfig # make your changes
cp linux/.config linux/arch/arm64/configs/imx8mm_venice_defconfig
  • Build kernel tarball: 
    make kernel_image # builds the kernel and modules and tarball
  • Build new disk image using the updated kernel tarball: 
    make ubuntu-image

Toolchain

Buildroot based toolchain

The Venice BSP uses buildroot to build the toolchain used to build the kernel and bootloader firmware.

The buidlroot config is ​venice/buildroot-imx8mm_venice_defconfig which is copied to buildroot/configs/imx8mm_venice_defconfig.

The bsp ​Makefile has a 'toolchain' target which is built as a pre-requisite for building the bootloader and kernel.

The buildroot version is 2020.05.3 and builds a toolchain with the following details (which are all defaults for buildroot):

  • Linux 5.6.x kernel headers
  • uClibc libc
  • binutils 2.32
  • gcc 8.x
  • C++ support (default is to disable this; we enable it)

The specific details can be shown by running 'gcc -v' for example: 

user@host:/usr/src/venice/bsp$ . ./setup-environment # configure PATH and CROSS_COMPILER env vars
user@host:/usr/src/venice/bsp$ ${CROSS_COMPILE}gcc -v
Using built-in specs.
COLLECT_GCC=/usr/src/venice/bsp/buildroot/output/host/bin/aarch64-linux-gcc.br_real
COLLECT_LTO_WRAPPER=/usr/src/venice/bsp/buildroot/output/host/libexec/gcc/aarch64-buildroot-linux-uclibc/8.4.0/lto-wrapper
Target: aarch64-buildroot-linux-uclibc
Configured with: ./configure --prefix=/usr/src/venice/bsp/buildroot/output/host --sysconfdir=/usr/src/venice/bsp/buildroot/output/host/etc --enable-static --target=aarch64-buildroot-linux-uclibc --with-sysroot=/usr/src/venice/bsp/buildroot/output/host/aarch64-buildroot-linux-uclibc/sysroot --enable-__cxa_atexit --with-gnu-ld --disable-libssp --disable-multilib --disable-decimal-float --with-gmp=/usr/src/venice/bsp/buildroot/output/host --with-mpc=/usr/src/venice/bsp/buildroot/output/host --with-mpfr=/usr/src/venice/bsp/buildroot/output/host --with-pkgversion='Buildroot 2020.05.3' --with-bugurl=http://bugs.buildroot.net/ --disable-libquadmath --disable-libsanitizer --enable-tls --enable-threads --without-isl --without-cloog --with-abi=lp64 --with-cpu=cortex-a53 --enable-languages=c,c++ --with-build-time-tools=/usr/src/venice/bsp/buildroot/output/host/aarch64-buildroot-linux-uclibc/bin --enable-shared --disable-libgomp
Thread model: posix
gcc version 8.4.0 (Buildroot 2020.05.3)

Note there are other options you may want to change for your needs such as using a different libc, different compiler version, or enable WCHAR support or additional threading support. To do so you can: 

cd buildroot
make menuconfig # select options desired under Toolchain
make clean
make
  • make sure you clean and rebuild when changing toolchain options

The buildroot based toolchain is used by virtue of sourcing the ​setup-environment file which adds to your PATH and sets the CROSS_COMPILE variable.

External toolchain

The Venice BSP uses buildroot to build the toolchain used to build the kernel and bootloader firmware.

While the BSP makefile will always build the buildroot toolchain (unless you comment that out in the Makefile) you can easily use a toolchain of your liking by modifying the environment like 'setup-environment' does. Simply make sure to set CROSS_COMPILE to the prefix of your toolchains 'gcc' compiler and other tools, and make sure your external toolchain shows up first in your PATH.

Cross compile examples

Examples of cross-compiling using the buildroot toolchain

  • ANSI-C hello world: 
    cat << EOF > helloworld.c
#include <stdio.h>
#include <stdlib.h>

int main(int argc, char **argv)
{
        printf("hello world!\n");

        return 0;
}
EOF
. ./setup-environment # setup environment for buildroot toolchain
${CROSS_COMPILE}gcc helloworld.c --static -o helloworld
    • Note that if you want to use shared libraries you would either need to copy the toolchains libc (buildroot/output/target/lib/) to the target so that the interpreter and shared libs are present or you can use Ubuntu's cross-toolchain instead (see ubuntu/cross-compile)
  • C++ hello world: 
    cat << EOF > helloworld.cpp
#include <iostream>

using namespace std;

int main() {
        cout << "Hello World!";
        return 0;
}
EOF
. ./setup-environment # setup environment for buildroot toolchain
${CROSS_COMPILE}gcc helloworld.cpp --static -lstdc++ -o helloworld
    • Note that if you want to use shared libraries you would either need to copy the toolchains libc (buildroot/output/target/lib/) to the target so that the interpreter and shared libs are present or you can use Ubuntu's cross-toolchain instead (see ubuntu/cross-compile)
  • kernel module: 
    . ./setup-environment # setup environment for buildroot toolchain
make kernel_image # first build the kernel
make -C linux M=$PWD/my-module modules
    • Note that some out-of-tree kernel modules do not follow the suggested Makefile standards and may need to be modified to use the CROSS_COMPILE prefix and/or specify the kernel directory (as opposed to the above example where you do a make in the linux dir and set M to the path of your module)

SSH using Ubuntu

By default root ssh access is disabled for security. See This link for info on enabling it

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