Mapping source file to recipes in yocto - yocto

To edit source in Yocto, I have to execute devtool modify <recipe>. I know the name of the source file, say foo.cpp, not the recipe. Using information captured elsewhere I can find out which recipe corresponds to my source file. To me that's the brute force method. Is there a recommended way to find the recipe using Yocto tools?
I have already viewed dependencies and reverse dependencies with Toaster. That did not help.

Related

In BitBake (Yocto), how to find what layer is using a dependency?

While building a Yocto image, BitBake fetches the files specified in layer recipes. When running bitbake, the process identifies missing files and tries to find them from mirrors.
Aside from searching the whole project for the missing file, is there a bitbake tool to identify a layer or recipe, given a broken package/file link?
One current example is:
expat-native-2.2.8-r0
tried, invalid: https://downloads.sourceforge.net/expat/expat-2.2.8.tar.bz2
use: https://github.com/libexpat/libexpat/releases/download/R_2_2_8/expat-2.2.8.tar.bz2
This question may be similar, but is out of date.
How do I find which layer is using the expat-native package?

Yocto determine what recipe a file came from

I am trying to determine how I can find what recipe a source file from the build/tmp/work directory came from. Basically normally most of the recipes in the source folder are uri. Then get downloaded and installed to various temp folders. I want to create a patch for some of the files, but I can't seem to figure out which files belong to what recipes.
Thank you
Run oe-pkgdata-util find-path /path/on/target/to/file. This will give you the package installing the file. From there, run oe-pkgdata-util lookup-recipe <pkg-name>, this will give you which recipe is creating the package. That should be enough to find out which recipe you need to modify. You then need to check whether the file you want to modify is part of the recipe (Yocto artifact) or part of the software that the recipe builds. For the former, you can override the file, for the latter, you can create a patch (you can use devtool to help you create the patch).

Create a mirror of all dependencies of Yocto-based project

I have a Yocto (poky)-based project where I would like to avoid downloading all the dependencies from the internet. I have found the PREMIRRORS variable that can be used to tell the build to get the dependencies from a local directory. The documentation does not, however, mention how to create such directory.
Is there some way to ask the build system to fetch all the packages to some place where they can be easily collected, or at least enumerate all the URLs so they can be mass-fetched?
See here please:
https://www.yoctoproject.org/docs/2.6/mega-manual/mega-manual.html#getting-source-files-and-suppressing-the-build
The directory can be then used directly as a PREMIRRORS location.

In yocto (poky) why is the layers config in the build/ folder?

I'm new to yocto. I'm trying to learn how the packages are added, how to create new layers and so on... just poking around. Started by cloning poky and playing around.
To my understanding, the bblayers.conf file is critical to the project configuration and what you end up building (what layers and packages go into your final image).
This might be the wrong assumption, but I also have a feeling that the build/ folder is where things you build (bitbake) stay. Images, lots of things needed to build them, a big cache of stuff... You can delete it and rebuild it if you somehow broke it. Or you can just copy everything without the build/ folder and continue working on a different computer.
Apparently it's not quite the case. The build/conf/ folder has the important .conf files like the bblayers.conf.
Can someone explain why is this the case? Is there an elegant way to separate the project config and the build folder?
There are a couple layers to the Yocto Project, mainly:
-BSPDIR: TOPDIR (build),sources,setup-environment
-BSPDIR/setup-environment: initial all the variable to for bitbake;
-BSPDIR/sources: meta-data/
-TOPDIR: conf/ sstate-cache/ cache/ tmp/ downloads/
-TOPDIR/downloads: recipe fetched packages;
-TOPDIR/conf/ : stored all the configuration. Mainly bblayers.conf, local.conf, sanity_info;
-TOPDIR/conf/bblayers.conf: stored all the path to meta-data that will be loaded;
-TOPDIR/conf/local.conf: configuration to build
-TOPDIR/conf/sanity_info: path double check to make sure that all the path used in the last compile match the current compile;
-TOPDIR/tmp/: Where all the compiling and building work happen
In BSPDIR/sources/poky/meta/conf/bitbake.conf
sources/poky/meta/conf/bitbake.conf:TMPDIR ?= "${TOPDIR}/tmp"
sources/poky/meta/conf/bitbake.conf:PERSISTENT_DIR = "${TOPDIR}/cache"
sources/poky/meta/conf/bitbake.conf:DL_DIR ?= "${TOPDIR}/downloads"
sources/poky/meta/conf/bitbake.conf:SSTATE_DIR ?= "${TOPDIR}/sstate-cache"
TOPDIR is where you initialize when run setup-environment or oe-init-build-env; All the other bitbake configuration environment variable can be changed based on your need in conf/local.conf;
e.g. modify conf/local.conf to change the downloads directory from TOPDIR/downloads;
DL_DIR ?= "/home/downloads/"
To create new layer, please watch this video: https://www.youtube.com/watch?v=3HsaoVqX7dg
You might have followed the Yocto Project Quick Start Guide.
The earliest step in yocto after installing (cloning git repositories and installing packages) is to create your OE (OpenEmbedded) environment, which is done via:
source oe-init-build-env
This automatically creates and leads you to the build folder.
Matter that you can give any directory of your system as parameter for this call (Reference Manual - Build Overview):
source oe-init-build-env [build_dir]
⤑ This is also the step, where your 'project config' is separated from the actual build folder.
⤑ As you assumed, in practice you would at most copy the layers and not the build folder. Even better is to leave sources from others in their git repositories and only copy and maintain your own layers.
it is true an issue in the modern Yocto build system.
file bblayers.conf has to be synthesized based on MACHINE and DISTRO information using all provided (usually with the help of repo manifest file) layers by: collecting data from each available layer file layer.conf as well as conf/machine, conf/distro, images.
Instead bblayers.conf is usually copied over from the base layer conf/bblayers.conf location with the help of setup-environment script.
this approach provides no "one click" buildable environment but require maintainer/developer to look into readme to identify what layers are missing to be added to the build/conf/bblayers.conf.

How to setup an own device tree for a RaspberryPI in yocto?

I like to disable and enable some pins in my RPi project.
These are GPIO 6, GPIO 5 and GPIO 26. I like to use these PINs in my own kernel driver.
For this project I connect a simple electric board via the GPIOs. The minimal system is build via yocto. I like to change the device tree file to disable/enable GPIOs.
I need to change or make my own dts file. For that I think I will need to:
find the original RPi dts
patch it or create my own dts
add it to the layer.conf
add file to the kernel recipe via append
How can I do this? or where can I find the sources?
Actually I am struggling to find the dts files for the RPi2 I am using. I was checking the "raspberrypi2-poky-linux-gnueabi" recipe results(and do not find any files).
I do not find any tutorial how to setup yocto + meta-raspberrypi + own dts. it would be great if we can figure out the necessary steps.
I'm not convinced this question has been well answered, so let me take a few minutes and document what I've done to add device tree overlays to my yocto builds.
This is a multi-problem process.
I'm going to make a few assumptions:
* You source your oe-init-build-env in a shell, and do your bitbake builds manually in a terminal (or you know how to do it with equivalent tooling)
* You know (or are already learning) the basics of device trees...
Start with your own meta layer. Mine is out on github.
You'll need to create an *-overlay.dts source file. You can start with a simple place holder, and stuff it (quite literally) anywhere on your system. We'll import it to your meta layer in the next step using bitbake to do some of the staging and what-not for us.
recipetool appendsrcfile -wm rpi /path/to/your-layer-meta virtual/kernel /path/to/your-overlay.dts 'arch/${ARCH}/boot/dts/overlays/your-overlay.dts
At this point, you should end up with a recipes-kernel/linux directory with an appropriate bbappend targeting the $MACHINE type of -wm (rpi, as above), ready to copy the device tree source file into the proper spot for bitbake to find it when it building the kernel. But it still won't be included in your kernel build.
We need to add the overlay reference to the KERNEL_DEVICETREE variable, in places that will cover the scopes of: linux, bootfiles, and the sdcard_image-rpi.bbclass from meta-raspberrypi.
In the linux bbappend created in step 3, add KERNEL_DEVICETREE += "overlays/your-overlay.dtbo" to make the linux kernel build include your dts as something to compile into a dtbo.
To make the sdcard_image-rpi.bbclass copy the file, you'll need to add KERNEL_DEVICETREE =+ "overlays/your-overlay.dtbo" to your image recipe.
To make the overlay active, you'll need to create a recipes-bsp/bootfiles/rpi-config_git.bbappend whereyou can append a do_deploy step to add the dtoverlay=your line to config.txt.
I use my layer for more than one project, so I felt OK with having the dts compile with every kernel but only copy it to images where my image recipe added it to the KERNEL_DEVICETREE. For further insurance that I don't get these things interferring in images I don't want them in, my rpi-config append has a test to see if I should add the dtoverlay line to the config.txt
Of course, this was all assuming you were going to use your own home-grown DTS without starting from a kernel-sourced one. The process would be largely the same, but you'd be able to patch the existing, or copy it, or whatever you want to do in your linux recipe.
I hope this helps! I know it's an old question.
First you need to find the kernel used on your yocto project, the recipe is linux-raspberry.bb or something like linux-*.bb. The preferred kernel is probably set in your local.conf or machine.conf: PREFERRED_PROVIDER_virtual/kernel ?= "linux-raspberry"
This is indirectly set via "meta-raspberrypi/conf/machine/include/rpi-default-providers.inc" which is included via "rpi-base.inc"
Once found, take a look at the recipe, clone the git repository of the kernel, on the right branch, and reset at the right SRCREV.
Once downloaded, the dts files are in /path/of/my/kernel/linux-raspberry/arch/arm/boot/dts/. You can find the name of the devicetree file used in the kernel recipe, local.conf or machine.conf, with the variable KERNEL_DEVICETREE = "..."
For the meta-raspberry and rpi2 selected, the dts files can be found in <path to build dir>/linux-raspberrypi2-standard-build/source/arch/arm/boot/dts/. The source dir is a linked dir to the git sources.
You can add a new dtb by creating dtsi/dts files (don't forget to add it in the Makefile).
Create a patch, add it to the kernel recipe:
SRC_URI += "file://0001-mypatch.patch"
and put the patch file like this in your meta
├── files
│   └── 0001-mypatch.patch
└── linux-raspberry.bb
Modify the KERNEL_DEVICETREE variable to add your new dtb.
Now you can bitbake your kernel/image, your new dtb will be created.