I have a custom board with imx6dl chip and peripherals. I have compiled u-boot, zImage and rootfs from examples provided by manufacturer. But when i try to build yocto from git repo with latests releases, it fails to run (some drivers not working, board is loading and display interface, but touchscreen is not working for ex.),
Is there any way to include precompiled binaries zImage, u-boot and device table to bitbake recipes? I'm very new to yocto project, and only need to get bootable image with working drivers and qt5.
If you have a working boot chain (e.g. u-boot, kernel and device tree) that you have built out-of-yocto, then you might try building a rootfs only. This requires two main settings, to be made in your local.conf to get started. Please don't firget that this is just a starting point, and it is highly advised to get the kernel/bootloader build sorted out really soon.
PREFERRED_PROVIDER_virtual/kernel = "linux-dummy to have no kernel being built, and something like MACHINE="qemuarm" to set up an armv7 build on poky later than version 3.0. The core-image-minimal target should at least be enough to drop you in a shell for starters, and then you can proceed from there.
Additionally, it might be qorth asking the board vendor or the yocto community (#yocto on the freenode server) if they know about a proper BSP layer. FSL things are quite nicely supported these days, and if your board is closely related to one of the well-known ones, you've got a high chance that meta-freescale just does the trick nicely.
Addition:
#Martin pointed out the mention of Qemu is misleading. This is just the easiest way to make Yocto build a userland for the armv7-architecture which the imx6dl is based on. The resulting root filesystem should be sufficiently compatible to get started, before moving on to more tuned MACHINE configuration.
Related
I've created a basic image with buildroot (buildroot-2021.02.1), containing some software and also selected the RPI firmware in order to use the camera and some Raspberry Pi tools: Target packages --> Hardware handling --> Firmware --> ([x] rpi-firmware) --> Firmware to boot as mentioned here.
But the tools raspistill, vcgencmd, ... are not included. The question is how to include them and why are they not included?
At some point in time it must have been working, see: RaspberryPi camera with buildroot
More details:
In the logs of buildroot the following lines show up:
>>> rpi-firmware d016a6eb01c8c7326a89cb42809fed2a21525de5 Installing to target
comm: /home/ich/br/buildroot/output/build/rpi-firmware-d016a6eb01c8c7326a89cb42809fed2a21525de5/.files-list.before: No such file or directory
comm: /home/ich/br/buildroot/output/build/rpi-firmware-d016a6eb01c8c7326a89cb42809fed2a21525de5/.files-list-staging.before: No such file or directory
comm: /home/ich/br/buildroot/output/build/rpi-firmware-d016a6eb01c8c7326a89cb42809fed2a21525de5/.files-list-host.before: No such file or directory
and inside this package the binaries are existing. They are downloaded from http://sources.buildroot.net/rpi-firmware/ where the tars contain the actual tools. But they are not copied into the final image by buildroot but only downloaded. Maybe because some files-list.txt file(s) are missing, as pointed out by the error message. Maybe those files are whitelisting the files to copy. But I could not find documentation about this.
For 64-bit builds the binaries in the (then manually downloaded) tar file could not be executed, because they are 32-bit executables: firmware-d016a6eb01c8c7326a89cb42809fed2a21525de5/opt/vc/bin/vcgencmd: ELF 32-bit LSB executable, ARM, EABI5 version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux.so.3, for GNU/Linux 3.1.9, not stripped; on a 32-bit build with buildroot it also does not work, because the shared libraries are missing, even though the full structure from the archive has been placed under /opt/vc/{bin|lib|...} like on a standard RPI image.
I'm unsure how to proceed with the problem, diagnose it and fix it.
EDIT: maybe this are two different problems; I read the linked SO question once again and compared the files fixup.dat and start.elf (which contain the RPI hardware stuff to make the tools work) in the boot.vfat of the built image with the images in buildroot/output/build/rpi-firmware-d016a6eb01c8c7326a89cb42809fed2a21525de5/boot and the files fixup_x.dat and start_x.elf are taken from there. So is in accordance to the mentioned SO question. And at no place it is indicated that the tools for the Raspberry Pi are compiled. They are only inside this tar archive. Maybe one needs to compile them extra and this package is not designed to integrate those tools.
I figured out the solution and this might be useful for future reference, so I put the solution here.
One have to differentiate between:
the "firmware" (that is the mentioned tar from the question), which is turned on with BR2_PACKAGE_RPI_FIRMWARE=y in buildroot. This causes then that the start.elf and fixup.dat contain the correct data from this tar. The fact that the tars also contain the desired binaries is only "coincidence"
the desired applications are packaged as "userland" (see here) and if one finds the # BR2_PACKAGE_RPI_USERLAND is not set line in .config in the buildroot project's root directory and replaces this line by BR2_PACKAGE_RPI_USERLAND=y the applications (vcgencmd, raspistill, ...) are being built and included into the final image (I could not find the location in make menuconfig however, but this is no problem, if you directly modify the vars)
Therefore, the question is answered. But: you might run into some issues ;-) :
Question 1: I get a "Segmentation fault" when running raspistill
For raspistill -o i.jpg you might get out:
mmal: mmal_vc_shm_init: could not initialize vc shared memory service
mmal: mmal_vc_component_create: failed to initialise shm for 'vc.camera_info' (7:EIO)
mmal: mmal_component_create_core: could not create component 'vc.camera_info' (7)
mmal: Failed to create camera_info component
Segmentation fault
(with an empty image file), see here for details.
Answer: this is related to /dev/vcsm (or /dev/vcsm-csa) missing which is used for camera control / video decoding "stuff". Symlinking to /dev/vc-mem as stated somewhere around the net does not help.
Solution: I was using the latest BR with Kernel 5.10.x (buildroot-2021.02.1 and simply "dowgraded" to buildroot-2020.02.1, rebuilt it and /dev/vcsm appears and everything works fine.
Question 2: I want to do it in docker containers
Answer: No problem. I used balenalib/rpi-raspbian:latest (as suggested here) and it worked flawlessly by running docker run --privileged --device=/dev/vchiq --rm -it balenalib/rpi-raspbian:latest. For this only the proper devices and the support is needed. So the package BR2_PACKAGE_RPI_USERLAND=y could be completely omitted.
Question 3: Does it work with 64-bit?
Answer: No. I tried out the recent version (raspberrypi3_64_defconfig) of buildroot and the version from Feb 2020 as mentioned and for both /dev/vcsm (or /dev/vcsm-csa) is missing. Linux cpi64 4.19.97-v8 #1 SMP PREEMPT Sat Apr 17 14:13:11 CEST 2021 aarch64 GNU/Linux
I'm trying to port Android 11 to my board(odroid-n2) and I'm confused about how I can build an board specific kernel module and ramdisk. Could I get some help about this?
Recently, to solve kernel fragmentation, it seems AOSP is splitting kernel into two different block.
(1) GKI(Generic Kernel Image)
(2) Vendor specific kernel
For GKI, I think I can use an image from ci.android.com.
For Vendor specific portion(Related to vendor_boot partition),
is there specific flow for this? or something to refer?
I'm referring to {android kernel}/common/build.config.db845c for case-study, I don't understand why 'gki_defconfig + db845c_gki.fragment' should be combined to one to generate configruation for kernel build. I think we only build kernel module for vendor specific portion.
*) For android docs, I'm referring to the followings.
https://source.android.com/setup/build/building-kernels
https://source.android.com/devices/architecture/kernel/generic-kernel-image
Indeed, with GKI (Generic Kernel Image), generic parts and vendor parts are separated. As of today, that distinction is quite clear: vmlinux is GKI and any module (*.ko) is vendor. That might change in the future if GKI modules show to be useful. Then there could be GKI (Kernel+Modules) + Vendor Modules.
The whole build process is quite new as well and still evolving with this quite fundamental change to how Android kernels are developed. Historically, device kernels and modules were build in one logical step and compatibility was ensured by the combined build. Now there is a shift towards a world where we can cleanly build the kernel and the modules entirely separate without overlap. It is likely to get much easier in the future to build vendor modules without having to build too much of the GKI kernel at the same time. Yet, the way the build currently works, it is easier to set up as it is.
Android 11 introduced the concept of "compliance" for GKI based kernels. That means a shipped kernel is ABI compatible to the GKI kernel. In theory that means that you could literally swap out the kernel that you have and replace it with a build from ci.android.com. Note, a compatible kernel can have significant (ABI compatible) patches that the GKI does not have. So, while compatible, it might not lead to the same experience.
Android 12 enables devices to be launched with signed boot images containing the GKI kernel. Since the Kernel<>Module ABI of those kernels is kept stable, this also allows independent updates of GKI kernel and vendor modules.
When you refer to the db845c build config, yes, this looks a bit confusing. This is a full blown config and the build indeed produces an (ABI compatible!) kernel and the vendor specific modules. The fragment can be considered a patch to the gki_defconfig in the sense that it does not change the core kernel, but enables the required modules.
For the final release, the kernel image from this build will be replaced by the GKI kernel image. But for development, the kernel that comes out of this build is perfectly fine to use.
In practice it helps downstream projects to develop core kernel features and modules at the same time, though changes for modules and kernel need to go into different repositories (db845c being an exception here a reference board).
To somewhat answer your question on how to build the db845c kernel, ci.android.com also provides the build log along with the artifacts to download. For the android12-5.10 branch and the target kernel_db845c, a recent build can be found here. The build.log states at the beginning the instructions to reproduce this:
$ BUILD_CONFIG=common/build.config.db845c build/build.sh
This is the relevant step based on the general instructions on source.android.com - building kernels.
I'm using Yocto project to build a linux kernel image following these steps:
https://www.at91.com/linux4sam/bin/view/Linux4SAM/Sama5d27Som1EKMainPage
For some reasons I just want to reduce my Image size so I can flash it on QSPI 8 Mega octet memory. I have tried to reduce the size of my rootFS, I have removed some packages that I found in .manifest file and some Distro features. But I did not find how can I modify the kernel size which size is fixed ( 4.2 Mega octet ).
I think that when I can remove some drivers that I don't need the kernel size will be reduced.
I just want to know how can I find what drivers are built in my image and where can I find them ? and later how can I delete the ones that I don't need ?
Thank you.
if you check the .config file that was generated for your BSP, it will show what drivers (and other things) were built into your kernel (check for the 'y' on all the options).
Such file should be somewhere in:
tmp/work//linux-yocto//linux-*-build/.config
Sorry that I can't give you the exact location, but it literally depends on what BSP/MACHINE you are building for.
Also, if you want to modify such configuration, you can call:
$ bitbake -c menuconfig virtual/kernel
that will bring up the menuconfig ncurses interface, in which you can not only see what is installed but also modify what you need.
I have an embedded linux "proof-of-concept" project that wants to add some packages to an existing piece of hardware with a read-only filesystem. I am very new (1 week) to Yocto but it seems like it is possible. Looking for a general road map of how to achieve this, but any detailed strategy ideas would be helpful to keep in mind as I RTFYM.
It is a networked device, running on ARMv5t hardware.
64GB SD/MMC card is available (empty) and mounted.
telnet, nfs, busybox utils available.
no resident dev tools
The packages I need to add are openssl, python, zeromq, pyzmq, and perhaps other python modules in the future. I cannot place these into the rootfs because it is read-only, but they can reside on the sd card. I am trying to understand how to use Yocto to create this set of packages and collect them together as a build output. What I have so far:
EXTERNAL_TOOLCHAIN and meta-sourcery recipe is working
I can build python and pyzmq independently with bitbake -b
Don't know how to add pyzmq or other modules to python tree
How to build & collect just these items without building entire image?
The python part is running on the hardware but I just hand-copied it to the nfs folder. I am asking if this is a valid approach and if so, to add some directional detail. I hope I have provided enough information.
A project I've inherited uses a very old version of buildroot, but I'd like to change it to use a feature that was added only in a later buildroot release.
Is there a straightforward way of updating a buildroot setup to use a later release?
e.g. if I save out a defconfig file and import that in a later buildroot release, would that just work, or are there practical reasons why not? Are there additional configuration files I'd need to carry across (e.g. kernel, busybox, etc)? Thanks!
No.
In fact, it's worse that that.
You can start by using a newer Buildroot version with your old default configuration file, but you will need to check the resulting configuration carefully for deprecated packages and packages whose versions are not compatible with whatever application software you might be adding to the Buildroot filesystem. The names of some packages (e.g. opencv) change over time, so you need to eyeball the resulting .config file to make sure that all of the packages that you need are there.
If you build a toolchain or Linux kernel in Buildroot (commonly done but not generally good practice), then you need to make sure that the new configuration is set to build the old version of the kernel and compiler. These might be too old to build some of the packages in the newer version of Buildroot.
If you upgrade your kernel at the same time that you upgrade Buildroot, then you need to port your old kernel config file to the new kernel version. Since the kernel configuration options change frequently, you will probably need to start from defconfig for your board and then use make menuconfig to manually add the configs that you need.
Busybox is a bit less volatile, so there is a chance that your old config will work.
If your old Buildroot configuration uses postbuild or postimage scripts, you will need to review them, but my guess is that they will not need any changes.
You should allocate at least a week for this work, maybe more, depending on the complexity of the configuration. Remember that if you are forced to use an older vendor kernel due to patches for a specific SoC, for example, the Freescale 2.6.33.9 kernel for the BSC9131, then the upgrade that you want to do might not be possible without doing six to twelve months of work to port the vendor's kernel patches to a newer kernel version.
Cheers.