Yocto 添加layer和创建layer

1. 查询可用的Layers

Yocto 提供了很多现成的layer，可以在Layer 索引中查询可用的layer。

OpenEmbedded Layer Index - layers
 

本节示例添加一个meta-intel的layer, 其对应的git 地址为：git://git.yoctoproject.org/meta-intel

2. 添加一个Layer

我们现在开始准备添加这个meta-intel的layer。

首先初始化poky的环境变量，使得bitbake 命令可用。

$ cd poky
$ source oe-init-build-env 

### Shell environment set up for builds. ###

You can now run 'bitbake <target>'

Common targets are:
    core-image-minimal
    core-image-full-cmdline
    core-image-sato
    core-image-weston
    meta-toolchain
    meta-ide-support

You can also run generated qemu images with a command like 'runqemu qemux86-64'.

Other commonly useful commands are:
 - 'devtool' and 'recipetool' handle common recipe tasks
 - 'bitbake-layers' handles common layer tasks
 - 'oe-pkgdata-util' handles common target package tasks

用bitbake-layers 查看当前的layer，当前有3个layers。

$ bitbake-layers --help
NOTE: Starting bitbake server...
usage: bitbake-layers [-d] [-q] [-F] [--color COLOR] [-h] <subcommand> ...

BitBake layers utility

optional arguments:
  -d, --debug           Enable debug output
  -q, --quiet           Print only errors
  -F, --force           Force add without recipe parse verification
  --color COLOR         Colorize output (where COLOR is auto, always, never)
  -h, --help            show this help message and exit

subcommands:
  <subcommand>
    show-layers         show current configured layers.
    show-overlayed      list overlayed recipes (where the same recipe exists in another layer)
    show-recipes        list available recipes, showing the layer they are provided by
    show-appends        list