yocto创建自己的machine

前面讲了如何离线构建yocto工程，这节讲如何创建自己的machine，在初始化yocto启动bitbake需要输入如下命令

 DISTRO=fsl-imx-fb MACHINE=imx6ull14x14evk source imx-setup-release.sh -b build

其中DISTRO用来指定发行版本 MACHINE用来指定硬件平台 build为构建的目录名称
指定好以上两个参数后在运行imx-setup-release.sh脚本

imx-setup-release.sh脚本分析

在该脚本中主要执行以下内容
1.sources/meta-imx/tools/setup-utils.sh 执行setup-utils.sh脚本
2.设置了默认的machine和distro（用于没有指定machine和distro）
3.设置yocto的基本环境变量，执行以下命令

MACHINE=$MACHINE . ./$PROGNAME $BUILD_DIR  即执行以下命令
./setup-environment build

4.向$BUILD_DIR/conf/local.conf 和 $BUILD_DIR/conf/bblayers.conf文件中写入重要参数
如我们要离线搭建yocoto工程local.conf中应该添加以下内容

#指定downloads路径
DL_DIR ?= "${BSPDIR}/downloads/"
# 指定SOURCE_MIRROR_URL路径
SOURCE_MIRROR_URL ?= "file://${DL_DIR}/"
#继承已有的mirror
INHERIT += "own-mirrors"
#禁止网络连接 只使用本地的源
BB_NO_NETWORK = "1"

即可以在 imx-setup-release.sh脚本中完成如

echo "BB_NO_NETWORK = \"1\"" >> $BUILD_DIR/conf/local.conf

#!/bin/sh
#
# i.MX Yocto Project Build Environment Setup Script
#
# Copyright (C) 2011-2016 Freescale Semiconductor
# Copyright 2017 NXP
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

. sources/meta-imx/tools/setup-utils.sh

CWD=`pwd`
PROGNAME="setup-environment"
exit_message ()
{
   echo "To return to this build environment later please run:"
   echo "    source setup-environment <build_dir>"

}

usage()
{
    echo -e "\nUsage: source imx-setup-release.sh
    Optional parameters: [-b build-dir] [-h]"
echo "
    * [-b build-dir]: Build directory, if unspecified script uses 'build' as output directory
    * [-h]: help
"
}


clean_up()
{

    unset CWD BUILD_DIR FSLDISTRO
    unset fsl_setup_help fsl_setup_error fsl_setup_flag
    unset usage clean_up
    unset ARM_DIR META_FSL_BSP_RELEASE
    exit_message clean_up
}

# get command line options
OLD_OPTIND=$OPTIND
unset FSLDISTRO

while getopts "k:r:t:b:e:gh" fsl_setup_flag
do
    case $fsl_setup_flag in
        b) BUILD_DIR="$OPTARG";
           echo -e "\n Build directory is " $BUILD_DIR
           ;;
        h) fsl_setup_help='true';
           ;;
        \?) fsl_setup_error='true';
           ;;
    esac
done
shift $((OPTIND-1))
if [ $# -ne 0 ]; then
    fsl_setup_error=true
    echo -e "Invalid command line ending: '$@'"
fi
OPTIND=$OLD_OPTIND
if test $fsl_setup_help; then
    usage && clean_up && return 1
elif test $fsl_setup_error; then
    clean_up && return 1
fi


if [ -z "$DISTRO" ]; then
    if [ -z "$FSLDISTRO" ]; then
        FSLDISTRO='fsl-imx-xwayland'
    fi
else
    FSLDISTRO="$DISTRO"
fi

if [ -z "$BUILD_DIR" ]; then
    BUILD_DIR='build'
fi

if [ -z "$MACHINE" ]; then
    echo setting to default machine
    MACHINE='imx6qpsabresd'
fi

case $MACHINE in
imx8*)
    case $DISTRO in
    *wayland)
        : ok
        ;;
    *)
        echo -e "\n ERROR - Only Wayland distros are supported for i.MX 8 or i.MX 8M"
        echo -e "\n"
        return 1
        ;;
    esac
    ;;
*)
    : ok
    ;;
esac

# Cleanup previous meta-freescale/EULA overrides
cd $CWD/sources/meta-freescale
if [ -h EULA ]; then
    echo Cleanup meta-freescale/EULA...
    git checkout -- EULA
fi
if [ ! -f classes/fsl-eula-unpack.bbclass ]; then
    echo Cleanup meta-freescale/classes/fsl-eula-unpack.bbclass...
    git checkout -- classes/fsl-eula-unpack.bbclass
fi
cd -

# Override the click-through in meta-freescale/EULA
FSL_EULA_FILE=$CWD/sources/meta-imx/EULA.txt

# Set up the basic yocto environment
if [ -z "$DISTRO" ]; then
   DISTRO=$FSLDISTRO MACHINE=$MACHINE . ./$PROGNAME $BUILD_DIR
else
   MACHINE=$MACHINE . ./$PROGNAME $BUILD_DIR
fi

# Point to the current directory since the last command changed the directory to $BUILD_DIR
BUILD_DIR=.

if [ ! -e $BUILD_DIR/conf/local.conf ]; then
    echo -e "\n ERROR - No build directory is set yet. Run the 'setup-environment' script before running this script to create " $BUILD_DIR
    echo -e "\n"
    return 1
fi

# On the first script run, backup the local.conf file
# Consecutive runs, it restores the backup and changes are appended on this one.
if [ ! -e $BUILD_DIR/conf/local.conf.org ]; then
    cp $BUILD_DIR/conf/local.conf $BUILD_DIR/conf/local.conf.org
else
    cp $BUILD_DIR/conf/local.conf.org $BUILD_DIR/conf/local.conf
fi

echo >> conf/local.conf
echo "# Switch to Debian packaging and include package-management in the image" >> conf/local.conf
echo "PACKAGE_CLASSES = \"package_deb\"" >> conf/local.conf
echo "EXTRA_IMAGE_FEATURES += \"package-management\"" >> conf/local.conf

if [ ! -e $BUILD_DIR/conf/bblayers.conf.org ]; then
    cp $BUILD_DIR/conf/bblayers.conf $BUILD_DIR/conf/bblayers.conf.org
else
    cp $BUILD_DIR/conf/bblayers.conf.org $BUILD_DIR/conf/bblayers.conf
fi


META_FSL_BSP_RELEASE="${CWD}/sources/meta-imx/meta-bsp"

echo "" >> $BUILD_DIR/conf/bblayers.conf
echo "# i.MX Yocto Project Release layers" >> $BUILD_DIR/conf/bblayers.conf
hook_in_layer meta-imx/meta-bsp
hook_in_layer meta-imx/meta-sdk
hook_in_layer meta-imx/meta-ml
hook_in_layer meta-nxp-demo-experience

echo "" >> $BUILD_DIR/conf/bblayers.conf
echo "BBLAYERS += \"\${BSPDIR}/sources/meta-browser\"" >> $BUILD_DIR/conf/bblayers.conf
echo "BBLAYERS += \"\${BSPDIR}/sources/meta-rust\"" >> $BUILD_DIR/conf/bblayers.conf
echo "BBLAYERS += \"\${BSPDIR}/sources/meta-clang\"" >> $BUILD_DIR/conf/bblayers.conf
echo "BBLAYERS += \"\${BSPDIR}/sources/meta-openembedded/meta-gnome\"" >> $BUILD_DIR/conf/bblayers.conf
echo "BBLAYERS += \"\${BSPDIR}/sources/meta-openembedded/meta-networking\"" >> $BUILD_DIR/conf/bblayers.conf
echo "BBLAYERS += \"\${BSPDIR}/sources/meta-openembedded/meta-filesystems\"" >> $BUILD_DIR/conf/bblayers.conf

echo "BBLAYERS += \"\${BSPDIR}/sources/meta-qt5\"" >> $BUILD_DIR/conf/bblayers.conf
echo "BBLAYERS += \"\${BSPDIR}/sources/meta-python2\"" >> $BUILD_DIR/conf/bblayers.conf

echo "BBLAYERS += \"\${BSPDIR}/sources/meta-bird-imx6ull\"" >> $BUILD_DIR/conf/bblayers.conf
if [ -d ../sources/meta-ivi ]; then
    echo -e "\n## Genivi layers" >> $BUILD_DIR/conf/bblayers.conf
    echo "BBLAYERS += \"\${BSPDIR}/sources/meta-gplv2\"" >> $BUILD_DIR/conf/bblayers.conf
    echo "BBLAYERS += \"\${BSPDIR}/sources/meta-ivi/meta-ivi\"" >> $BUILD_DIR/conf/bblayers.conf
    echo "BBLAYERS += \"\${BSPDIR}/sources/meta-ivi/meta-ivi-bsp\"" >> $BUILD_DIR/conf/bblayers.conf
    echo "BBLAYERS += \"\${BSPDIR}/sources/meta-ivi/meta-ivi-test\"" >> $BUILD_DIR/conf/bblayers.conf
fi

echo "BB_NO_NETWORK = \"1\"" >> $BUILD_DIR/conf/local.conf
echo BSPDIR=$BSPDIR
echo BUILD_DIR=$BUILD_DIR

# Support integrating community meta-freescale instead of meta-fsl-arm
if [ -d ../sources/meta-freescale ]; then
    echo meta-freescale directory found
    # Change settings according to environment
    sed -e "s,meta-fsl-arm\s,meta-freescale ,g" -i conf/bblayers.conf
    sed -e "s,\$.BSPDIR./sources/meta-fsl-arm-extra\s,,g" -i conf/bblayers.conf
fi

cd  $BUILD_DIR
clean_up
unset FSLDISTRO

setup-environment分析

在该脚本中主要做了以下工作
1.判断是否为root
2.判断machine和distro是否设置
3.是否是第一次构建
4.添加一些信息到local.cof
5.最重要的是执行该命令

. $OEROOT/oe-init-build-env $CWD/$1 > /dev/null
即source/poky/下的oe-init-build-env

oe-init-build-env分析

该脚本首先判断了shell是采用那种方式调用的该脚本 . 还是 **./**或者是其他方式

This script needs to be sourced. Please run as '.

随后执行了

export OEROOT
. $OEROOT/scripts/oe-buildenv-internal &&
    TEMPLATECONF="$TEMPLATECONF" $OEROOT/scripts/oe-setup-builddir || {
    unset OEROOT
    return 1
}
即执行$PWD/sources/poky目录下的子目录scripts中的oe-buildenv-internal和oe-setup-builddir脚本
[ -z "$BUILDDIR" ] || cd "$BUILDDIR"
判断oe-buildenv-internal和oe-setup-builddir脚本中是否设置了BUILDDIR变量，如果设置了，切换到他表示的目录里

① 检测OEROOT变量是否定义，如果没定义脚本立刻返回。OEROOT变量在oe-init-build-env脚本中设置，该变量表示oe-init-build-env脚本所在目录位置信息

② 检测主机安装python版本信息，Python2需大于2.7.3，Python3需大于3.4.0

③ 设置BUILDDIR变量等于构建目录的绝对路径信息。如果执行该脚本时没指定构建目录的路径为脚本的第一个参数的话，脚本设置使用"build"作为默认构建目录名

④ 令BITBAKEDIR="$OEROOT/bitbake，该路径是存放bitbake工具集和脚本的路径

⑤ 将"$BITBAKEDIR/bin" "$OEROOT/scripts"路径临时增加到PATH环境变量中，$BITBAKEDIR/bin路径存放的是bitbake工具，$OEROOT/scripts目录存放的是构建的脚本

⑥ 设置构建工具集使用的环境变量

回到正题

如何创建自己的machine

1.创建自己的meta-layer
在source目录下创建 meta-bird-imx6ull其结构如下
在这里插入图片描述

conf

该层中包含一个最重要的layer.conf和distro machine目录

conf中的layer.conf

layer.conf 定义了构建layer的参数配置 所需文件路径等 可以其他meta-layer中的layer.conf 移植而来

使用bitbake-layers show-layers可以查看所有的layer 及其编译时的 priority找到优先级最高的meta-layer对应的layer.conf 移植
即 fsl-yocto-release/sources/meta-imx/meta-bsp/conf/layer.conf

怎么修改？

1.修改   BBFILE_COLLECTIONS += "fsl-bsp-release" 为 BBFILE_COLLECTIONS += "meta-bird-imx6ull"
2.删除与imx6ull不相关的部分

conf中的machine

将/sources/metaimx/meta-bsp/conf/machine路径下的imx6ull14x14evk.conf文件拷贝至/sources/meta-birdimx6ull/machine路径下，并将其重命名为imx6ull-bird-dk.conf，作为我们构建系统所使用的硬件平台
的配置文件

conf中的distro

/sources/meta-imx/meta-sdk/conf/distro下的fsl-imx-fb.conf文件拷贝至/sources/meta-birdimx6ull/conf/distro/路径下，并将其重命名为bird-imx-fb.conf

使能meta-layer

添加BBLAYERS += "${BSPDIR}/sources/meta-bird-imx6ull"到bblayer.conf
即在imx-setup-relesas.sh中添加

echo "BBLAYERS += \"\${BSPDIR}/sources/meta-bird-imx6ull\"" >> $BUILD_DIR/conf/bblayers.conf

完成

完成后使用以下命令构建yocto

 DISTRO=bird-imx-fb MACHINE=imx6ull-bird-dk source imx-setup-release.sh -b build

进入build后使用bitbake-layers show-layers可以查看到meta-bird-imx6ull