Yocto BSP 開發說明
內容參考:http://www.yoctoproject.org/docs/2.0/bsp-guide/bsp-guide.html#bsp
簡介:
一個BSP(BoardSupport Package) 定義瞭如何去支持一個或者一類特定的硬件設備,或者硬件平臺.
1 BSP layers:
BSP layers 的命名: meta-bsp_name, 如meta-minnow, meta-raspberrypi, and meta-intel .
源碼來源: http://git.yoctoproject.org/cgit/cgit.cgi
git clone git://git.yoctoproject.org/meta-minnow
向conf/bblayers.conf: BBLAYERS 添加BSP的layers 路徑
2 從文件組織來說明BSPlayers
下面是可能存在差異的文件列表:
meta-bsp_name/
meta-bsp_name/bsp_license_file
meta-bsp_name/README
meta-bsp_name/README.sources
meta-bsp_name/binary/bootable_images
meta-bsp_name/conf/layer.conf
meta-bsp_name/conf/machine/*.conf
meta-bsp_name/recipes-bsp/*
meta-bsp_name/recipes-core/*
meta-bsp_name/recipes-graphics/*
meta-bsp_name/recipes-kernel/linux/linux-yocto_kernel_rev.bbappend
下面是eMenlow的文件列表:
meta-emenlow/COPYING.MIT
meta-emenlow/README
meta-emenlow/README.sources
meta-emenlow/binary/
meta-emenlow/conf/
meta-emenlow/conf/layer.conf
meta-emenlow/conf/machine/
meta-emenlow/conf/machine/emenlow-noemgd.conf
meta-emenlow/recipes-bsp/
meta-emenlow/recipes-bsp/formfactor/
meta-emenlow/recipes-bsp/formfactor/formfactor/
meta-emenlow/recipes-bsp/formfactor/formfactor_0.0.bbappend
meta-emenlow/recipes-bsp/formfactor/formfactor/emenlow-noemgd/
meta-emenlow/recipes-bsp/formfactor/formfactor/emenlow-noemgd/machconfig
meta-emenlow/recipes-graphics/
meta-emenlow/recipes-graphics/xorg-xserver
meta-emenlow/recipes-graphics/xorg-xserver/xserver-xf86-config
meta-emenlow/recipes-graphics/xorg-xserver/xserver-xf86-config_0.1.bbappend
meta-emenlow/recipes-graphics/xorg-xserver/xserver-xf86-config/emenlow-noemgd
meta-emenlow/recipes-graphics/xorg-xserver/xserver-xf86-config/emenlow-noemgd/xorg.config
meta-emenlow/recipes-kernel/
meta-emenlow/recipes-kernel/linux/
meta-emenlow/recipes-kernel/linux/linux-yocto-dev.bbappend
meta-emenlow/recipes-kernel/linux/linux-yocto_3.14.bbappend
2.1 License Files
meta-bsp_name/bsp_license_file
eMenlow 的license 文件是COPYING.MIT.
還可以是MIT,BSD, GPLv* 等等.
2.2 README
meta-bsp_name/README , 它需要提供如何啓動的方法,最少也得包含依賴關係和聯繫方式.
2.3. README.sources
meta-bsp_name/README.sources , 它提供了BSP源代碼的存儲路徑和來源地址.
2.4. Pre-built User Binaries
meta-bsp_name/binary/bootable_images , 存儲了已經編譯好的二進制kernel和rootfs.
2.5. Layer Configuration File
meta-bsp_name/conf/layer.conf ,下面是模版,需要用真實的名字替換掉bsp.
# We have a conf and classes directory, add to BBPATH
BBPATH .= ":${LAYERDIR}"
# We have a recipes directory, add to BBFILES
BBFILES += "${LAYERDIR}/recipes-*/*/*.bb \
${LAYERDIR}/recipes-*/*/*.bbappend"
BBFILE_COLLECTIONS += "bsp"
BBFILE_PATTERN_bsp = "^${LAYERDIR}/"
BBFILE_PRIORITY_bsp = "6"
LAYERDEPENDS_bsp = "intel"
2.6. Hardware Configuration Options
meta-bsp_name/conf/machine/*.conf
硬件的配置信息.
2.7. Miscellaneous BSP-Specific Recipe Files
meta-bsp_name/recipes-bsp/*
包含一些BSP特定的package.
2.8. Display Support Files
meta-bsp_name/recipes-graphics/*
它可以代表一類可以運行在該BSP上的package.
2.9. Linux Kernel Configuration
meta-bsp_name/recipes-kernel/linux/linux-yocto*.bbappend
它可以配置kernel信息.
3 發佈BSP的需求和推薦
3.1. Released BSP Requirements
在GIT上發佈一個BSP,我們需要嚴格按照BSP的書寫格式填寫相關的文件.
3.2. Released BSP Recommendations
發佈BSP的可選項: 可啓動的bootimage 以及 一個特定的yoctokernel recipes.
4 自定義一個BSP的recipe
在”xyz”中定義一個BSP相關的interfaces工具基於init-ifupdown_1.0.bb.
· 編輯init-ifupdown_1.0.bbappend
FILESEXTRAPATHS_prepend := "${THISDIR}/files:"
· 建立interfaces的存儲位置
meta-xyz/recipes-core/init-ifupdown/files/xyz-machine-one/interfaces
如果BSP只支持一個硬件機器,可以改爲: meta-xyz/recipes-core/init-ifupdown/files/interfaces
5 BSP的Licensing考慮事項
…
6 使用Yocto的BSP 工具
Yocto 工程已經包含了一系列的BSP 工具 : yocto-bsp 和 yocto-kernel .
6.1. Common Features
$ source oe-init-build-env build_dir
$ yocto-bsp help
$ yocto-bsp help create
6.2. 通過yocto-bsp工具創建BSPlayers
$ yocto-bsp list karch
Architectures available:
qemu
mips64
powerpc
x86_64
arm
mips
i386
$ yocto-bsp create myarm qemu
Checking basic git connectivity...
Done.
Which qemu architecture would you like to use? [default: i386]
1) i386 (32-bit)
2) x86_64 (64-bit)
3) ARM (32-bit)
4) PowerPC (32-bit)
5) MIPS (32-bit)
6) MIPS64 (64-bit)
3
Would you like to use the default (3.19) kernel? (y/n) [default: y] y
Do you need a new machine branch for this BSP (the alternative is to re-use an existing branch)? [y/n] [default: y]
Getting branches from remote repo git://git.yoctoproject.org/linux-yocto-3.19.git...
Please choose a machine branch to base your new BSP branch on: [default: standard/base]
1) standard/arm-versatile-926ejs
2) standard/base
3) standard/beagleboard
4) standard/beaglebone
5) standard/ck
6) standard/common-pc
7) standard/crownbay
8) standard/edgerouter
9) standard/fsl-mpc8315e-rdb
10) standard/mti-malta32
11) standard/mti-malta64
12) standard/qemuarm64
13) standard/qemuppc
1
Would you like SMP support? (y/n) [default: y]
Does your BSP have a touchscreen? (y/n) [default: n]
Does your BSP have a keyboard? (y/n) [default: y]
New qemu BSP created in meta-myarm
6.3. 通過yocto-kernel工具管理KernelPatches and Config
$ yocto-kernel --help
$ yocto-kernel patch add myarm ~/test.patch
Added patches:
test.patch
$ yocto-kernel patch add myarm ~/yocto-testmod.patch
Added patches:
yocto-testmod.patch
$ yocto-kernel patch list myarm
The current set of machine-specific patches for myarm is:
1) test.patch
2) yocto-testmod.patch
$ yocto-kernel patch rm myarm
Specify the patches to remove:
1) test.patch
2) yocto-testmod.patch
1
Removed patches:
test.patch
$ yocto-kernel patch list myarm
The current set of machine-specific patches for myarm is:
1) yocto-testmod.patch
$ yocto-kernel config add myarm CONFIG_MISC_DEVICES=y
Added item:
CONFIG_MISC_DEVICES=y
$ yocto-kernel config add myarm CONFIG_YOCTO_TESTMOD=y
Added item:
CONFIG_YOCTO_TESTMOD=y
$ yocto-kernel config list myarm
The current set of machine-specific kernel config items for myarm is:
1) CONFIG_MISC_DEVICES=y
2) CONFIG_YOCTO_TESTMOD=y
$ yocto-kernel config rm myarm CONFIG_MISC_DEVICES=y