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| software:linux:toradex:toradex-build [2019-10-16 12:14] – mlammerich | software:linux:toradex:toradex-build [Unbekanntes Datum] (aktuell) – gelöscht - Externe Bearbeitung (Unbekanntes Datum) 127.0.0.1 |
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| ====== Building a New Image ====== | |
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| Images are built using bitbake and yocto. | |
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| The build process is based on [[ https://developer.toradex.com/knowledge-base/board-support-package/openembedded-%28core%29#update-to-a-specific-version-by-using-its-tag | this toradex guide ]]. | |
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| ===== Customising the Toradex image ===== | |
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| Note that everything in this section assumes a build environment that is set up accoring to the guide above. | |
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| ==== Adding a custom application ==== | |
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| A custom application can be added to a yocto build by means of a new recipes and a new layer. | |
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| There are various ways to source application to be added to a build. This guide describes how to add [[ https://github.com/DynamicDevices/bbexample | this hello world application from github ]] into the toradex image. If you want to build your own hello world application, check out [[ https://blog.mbedded.ninja/programming/embedded-linux/yocto-project/adding-a-custom-app-to-a-yocto-build/ | this guide ]] on how to do that. | |
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| === On layers and recipes === | |
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| Recipes could be considered the fundamental building block of yocto. A recipe describes how to build the thing you want to build (i.e an application, kernel module, ...), its dependencies and more. | |
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| Groups of recipes that belong together are grouped into layers. For example ''meta-toradex-nxp'' is the layer that contains all the things needed to support the hardware specific to Toradex's modules that use NXP based processors. | |
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| === Creating a custom layer === | |
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| To create a new layer, create a new directory in the ''oe-core/layers'' directory(''oe-core'' is the folder the build environment was set up in above). Since this is the NTB wiki, this guide will use ''oe-core/layers/meta-ntb''. The directory name can be anything, but it should start with ''meta-''. Now change into that directory and create another folder called ''conf''. In ''conf'', create a file named ''layer.conf'' with the following content: | |
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| <code> | |
| BBPATH := "${BBPATH}:${LAYERDIR}" | |
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| BBFILES := "${BBFILES} ${LAYERDIR}/recipes-*/*/*.bb ${LAYERDIR}/recipes-*/*/*.bappend" | |
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| BBFILE_COLLECTIONS += "ntb" | |
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| BBFILE_PATTERN_ntb := "^${LAYERDIR}/" | |
| BBFILE_PRIORITY_ntb := "5" | |
| </code> | |
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| This file configures the layer and where to look for recipes. In this case it will look for file in ''meta-ntb/recipes-<some name>/<some other name>/<file name>.bb''. ''.bb'' is the file extension used by ''bitbake'' the build system used by yocto. Finally, create a folder named ''recipes-ntb'' inside ''meta-ntb''. This folder will store all the recipes for this layer. The directory structure should now look like this: | |
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| * oe-core | |
| * ... | |
| * meta-ntb | |
| * conf | |
| * layer.conf | |
| * recipes-ntb | |
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| === Adding a Recipe to the Layer === | |
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| As configured above, ''bitbake'' will look for recipes in any sub directory | |
| of ''recipes-ntb'', **but not in ''recipes-ntb'' itself!** Create a folder inside ''recipes-ntb'' called ''helloworld'' and inside that create a file called ''helloworld_1_0.bb'' with the following content: | |
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| <code> | |
| DESCRIPTION = "Example Hello World" | |
| SECTION = "ntb" | |
| DEPENDS = "" | |
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| LICENSE = "MIT" | |
| LIC_FILES_CHKSUM = "file://LICENSE;md5=96af5705d6f64a88e035781ef00e98a8" | |
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| FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}-${PV}:" | |
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| SRCREV = "b9fb7785e9e1f357f29bef63dce8f1d91adb6170" | |
| SRC_URI = "git://github.com/DynamicDevices/bbexample.git" | |
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| S = "${WORKDIR}/git" | |
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| inherit autotools | |
| </code> | |
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| ''bitbake'' is very particular about licenses to ensure no closed source software ends up in a project that only wants open source software. Hence the recipe needs to specify the license used (MIT in this case) and a checksum for the license file to ensure it has not been altered. All this is handled by the ''LIC_FILES_CHKSUM'' field. THe other two interesting fields are ''SRC_URI'' and ''SRC_REV''. ''SRC_URI'' specifies where the source for the application/module/... for this recipe is. In this case ''git:%%//%%'' lets ''bitbake'' know the source lives in a git repository. Note that ''https:%%//%%'' will not work. | |
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| Now running ''bitbake console-tdx-image'' should run without errors and the image should include a ''hello'' executable that prints ''Hello World'' when executed. | |
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| == Additional Information == | |
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| [[ https://blog.mbedded.ninja/programming/embedded-linux/yocto-project/adding-a-custom-app-to-a-yocto-build/ ]] | |
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| [[ https://wiki.yoctoproject.org/wiki/Building_your_own_recipes_from_first_principles ]] | |
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| ===== Building the SDK ===== | |
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| To build the SDK for an image append '' -c populate_sdk'' to the bitbake build command. | |
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| For example, to build the SDK for the standard toradex image ''console-tdx-image'' run ''bitbake console-tdx-image -c populate_sdk'' | |
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| For more information check the [[ https://developer.toradex.com/knowledge-base/linux-sdks | Toradex guide ]]. | |
