1.. SPDX-License-Identifier: CC-BY-SA-2.0-UK 2 3============================================================= 4Transitioning to a custom environment for systems development 5============================================================= 6 7| 8 9.. note:: 10 11 So you've finished the :doc:`brief-yoctoprojectqs/index` and 12 glanced over the document :doc:`what-i-wish-id-known`, the latter contains 13 important information learned from other users. You're well prepared. But 14 now, as you are starting your own project, it isn't exactly straightforward what 15 to do. And, the documentation is daunting. We've put together a few hints to 16 get you started. 17 18#. **Make a list of the processor, target board, technologies, and capabilities 19 that will be part of your project**. 20 You will be finding layers with recipes and other metadata that support these 21 things, and adding them to your configuration. (See #3) 22 23#. **Set up your board support**. 24 Even if you're using custom hardware, it might be easier to start with an 25 existing target board that uses the same processor or at least the same 26 architecture as your custom hardware. Knowing the board already has a 27 functioning Board Support Package (BSP) within the project makes it easier 28 for you to get comfortable with project concepts. 29 30#. **Find and acquire the best BSP for your target**. 31 Use the :yocto_home:`Yocto Project Compatible Layers 32 </software-overview/layers/>` or even the :oe_layerindex:`OpenEmbedded 33 Layer Index <>` to find and acquire the best BSP for your 34 target board. The Yocto Project layer index BSPs are regularly validated. The 35 best place to get your first BSP is from your silicon manufacturer or board 36 vendor – they can point you to their most qualified efforts. In general, for 37 Intel silicon use meta-intel, for Texas Instruments use meta-ti, and so 38 forth. Choose a BSP that has been tested with the same Yocto Project release 39 that you've downloaded. Be aware that some BSPs may not be immediately 40 supported on the very latest release, but they will be eventually. 41 42 You might want to start with the build specification that Poky provides 43 (which is reference embedded distribution) and then add your newly chosen 44 layers to that. Here is the information :ref:`about adding layers 45 <dev-manual/layers:Understanding and Creating Layers>`. 46 47#. **Based on the layers you've chosen, make needed changes in your 48 configuration**. 49 For instance, you've chosen a machine type and added in the corresponding BSP 50 layer. You'll then need to change the value of the :term:`MACHINE` variable in your 51 configuration file (build/local.conf) to point to that same machine 52 type. There could be other layer-specific settings you need to change as 53 well. Each layer has a ``README`` document that you can look at for this type of 54 usage information. 55 56#. **Add a new layer for any custom recipes and metadata you create**. 57 Use the ``bitbake-layers create-layer`` tool for Yocto Project 2.4+ 58 releases. If you are using a Yocto Project release earlier than 2.4, use the 59 ``yocto-layer create`` tool. The ``bitbake-layers`` tool also provides a number 60 of other useful layer-related commands. See 61 :ref:`dev-manual/layers:creating a general layer using the 62 \`\`bitbake-layers\`\` script` section. 63 64#. **Create your own layer for the BSP you're going to use**. 65 It is not common that you would need to create an entire BSP from scratch 66 unless you have a *really* special device. Even if you are using an existing 67 BSP, :ref:`create your own layer for the BSP <bsp-guide/bsp:creating a new 68 bsp layer using the \`\`bitbake-layers\`\` script>`. For example, given a 69 64-bit x86-based machine, copy the conf/intel-corei7-64 definition and give 70 the machine a relevant name (think board name, not product name). Make sure 71 the layer configuration is dependent on the meta-intel layer (or at least, 72 meta-intel remains in your bblayers.conf). Now you can put your custom BSP 73 settings into your layer and you can re-use it for different applications. 74 75#. **Write your own recipe to build additional software support that isn't 76 already available in the form of a recipe**. 77 Creating your own recipe is especially important for custom application 78 software that you want to run on your device. Writing new recipes is a 79 process of refinement. Start by getting each step of the build process 80 working beginning with fetching all the way through packaging. Next, run the 81 software on your target and refine further as needed. See :ref:`Writing a New 82 Recipe <dev-manual/new-recipe:writing a new recipe>` in the 83 Yocto Project Development Tasks Manual for more information. 84 85#. **Now you're ready to create an image recipe**. 86 There are a number of ways to do this. However, it is strongly recommended 87 that you have your own image recipe --- don't try appending to existing image 88 recipes. Recipes for images are trivial to create and you usually want to 89 fully customize their contents. 90 91#. **Build your image and refine it**. 92 Add what's missing and fix anything that's broken using your knowledge of the 93 :ref:`workflow <sdk-manual/extensible:using \`\`devtool\`\` in your sdk 94 workflow>` to identify where issues might be occurring. 95 96#. **Consider creating your own distribution**. 97 When you get to a certain level of customization, consider creating your own 98 distribution rather than using the default reference distribution. 99 100 Distribution settings define the packaging back-end (e.g. rpm or other) as 101 well as the package feed and possibly the update solution. You would create 102 your own distribution in a new layer inheriting from Poky but overriding what 103 needs to change for your distribution. If you find yourself adding a lot of 104 configuration to your local.conf file aside from paths and other typical 105 local settings, it's time to :ref:`consider creating your own distribution 106 <dev-manual/custom-distribution:creating your own distribution>`. 107 108 You can add product specifications that can customize the distribution if 109 needed in other layers. You can also add other functionality specific to the 110 product. But to update the distribution, not individual products, you update 111 the distribution feature through that layer. 112 113#. **Congratulations! You're well on your way.** 114 Welcome to the Yocto Project community. 115 116.. include:: /boilerplate.rst 117