linux - 如何为使用 Debian 库的示例 "hello world"程序配置 Yocto？

Question

我在我的 Debian VM 中构建了一个简单的软件。它尝试从 FTP 服务器下载文件。为此，我使用 libcurl 库 (libcurl-openssl-dev)。

现在我有一个 SAMA5D3x-Evalboard 可用。出于自学目的，我喜欢为它构建一个 Linux + 工具链。我找到了 Yocto 项目。元层概念似乎是管理不同平台的好方法 - 让我们试试吧!我在网上找到了一些例子。但没有涵盖“hello world”+ bigger lib 的组合。

我要:

获取X编译工具链+Linux镜像(包括我的hello world+libcurl共享对象)

我的方法:

• meta-atmel:用于 SAMA5D3x 评估板
• meta-debian:用于库“libcurl-openssl-dev”
• meta-mySoftware:用于 hello world 程序

约束是:

• main.c - Hello World 程序的名称
• libcurl - c 库名(我选择这个库，因为它有很多依赖)

如何正确设置？如果有更好的想法，欢迎提出!

Answer 1

Yocto 的安装和配置

I.) 安装工具链

I.1.) apt-get:

sudo apt-get install gawk wget git-core diffstat unzip texinfo gcc-multilib build-essential chrpath socat libsdl1.2-dev xterm

I.2.) 选择。代理后配置git

git config --global core.gitproxy <gitproxy>

I.3.) 下载工具链 + 元包并检查“正确的”提交

git clone git://git.yoctoproject.org/poky
cd poky
git checkout jethro

git clone git://github.com/linux4sam/meta-atmel.git
cd meta-atmel
git checkout jethro
cd ..

git clone git://git.openembedded.org/meta-openembedded
cd meta-openembedded
git checkout jethro
cd ..

II.) 为 SAMA5D3x 构建内核+rootfs

II.1) 创建新项目

source oe-init-build-env

新项目在“build”目录下创建通过 commandos 修改层“conf/bblayers.conf”

bitbake-layers add-layer "../meta-atmel"
bitbake-layers add-layer "../meta-openembedded/meta-oe"
bitbake-layers add-layer "../meta-openembedded/meta-networking"
bitbake-layers add-layer "../meta-openembedded/meta-python"

编辑“conf/local.conf”

MACHINE ??= "sama5d3xek"
DL_DIR ?= "${TOPDIR}/../downloads"
DISTRO ?= "poky-atmel"

下载目录在构建环境之外。下载的源可用于不同的构建。

II.2) 创建图像

bitbake -c clean core-image-minimal
bitbake core-image-minimal

结果文件创建在“tmp/deploy/images/sama5d3xek”

II.3) 闪存图像

需要 Atmel 的 sam-ba 工具。 Flash-Process 可以通过脚本自动执行(我们创建一个 tcl 文件)。自写工具“buildAtmelImages.py”复制 SAMA5D35 所需的图像文件，创建 u-boot 配置和 Flash-Script。一个例子:

python buildAtmelImages.py --help
python buildAtmelImages.py -s "/home/user/poky/build/tmp/deploy/images/sama5d3xek" -d "/home/user/images" -t "\\\\1.2.3.4\\admin\\images"

这里是“buildAtmelImages.py”的代码:

#!/usr/bin/python
# encoding: utf-8
'''
buildAtmelImages -- make yocto build images ready of the sam-ba flash tool 

buildAtmelImages is a description

- reverse engineered /meta-atmel/scripts/nandflash.tcl script
- works only for the SAMA5D35
- params:
    -s "<dir>" = source dir of the images generated by yocto. like "/home/user/poky/build/tmp/deploy/images/sama5d3xek"
    -d "<dir>" = destination dir
    -t "<dir/url>" = tcl refence dir. The path to the images, used to flash, is hard coded in the tcl script. typical example "\\\\192.168.1.2\\admin\\images" for an samba based network 
- way of operation:
# hints:
I.) the SAMA5D3x implements some ECC features. This means that in every NAND sector are bits for error correction reserved.
This acts into 2 directions:
1.) the binary files have to be flashed by takeing care of the extra ECC bits. This is done by the sam-ba flash tool
2.) the kernel needs to take care, that the data stored on the NAND drive has some extra handling. This is managed by the meta-atmel package used by the yocto toolchain.

II.) u boot configuration
1.) the u boot configuration is placed into the NAND. But the configuration is not generated by the yocto toolchain. Atmel delivers a flashing script for its demo boards. This was reversed engineered into this python script.
The layout of the boot config is a defined memory space which is guared by an crc32(litle endian). The boot configuration is placed as ANSII string parameters. These parameters are seperated by a zero.

2.) because of the ecc the binary device tree(dtb) and kernel needs to be copied to memory before been executed. For that it is needed that u-boot loads them into ram before starting the kernel.

# operation:
First the generated images are copied. After the configuartion is generated and placed into the output dir. At least the tcl script is generated and placed into the output dir, as well. 

@author:     Stefan Jaritz

@copyright:  

@license:    license

@contact:    
@deffield    updated: Updated
'''

import sys
import os
import shutil
import binascii
import struct


from argparse import ArgumentParser
from argparse import RawDescriptionHelpFormatter


__all__ = []
__version__ = 0.1
__date__ = '2016-04-19'
__updated__ = '2016-04-19'

class _memorySeg():
    def __init__(self, add, sf, df):
        self.add = add
        self.sf = sf
        self.df = df

gArch = 'sama5d3xek'

gTCLfilename = 'SEK4.tcl'

gMemSetup = {
       'bootloader' : _memorySeg(0x00000000, 'at91bootstrap-sama5d3xek.bin', 'bootloader.bin'),
       'uboot' : _memorySeg(0x00040000, 'u-boot-sama5d3xek.bin', 'uboot.bin'),
       'ubootEnv' : _memorySeg(0x000c0000, None, 'ubootEnv.bin'),
       'ubootEnvRed' : _memorySeg(0x00100000, None, 'ubootEnv.bin'),
       'dtb' : _memorySeg(0x00180000,'zImage-sama5d35ek.dtb', 'kernel.dtb'),
       'kernel' : _memorySeg(0x00200000,'zImage', 'kernel'),
       'rootfs' : _memorySeg(0x00800000,'core-image-minimal-sama5d3xek.ubi', 'rootfs.ubi')
    }


gSourceDir = ''
gDestDir = ''
gTCLfilepath = ''

gECCcnfg = {
    'at91sam9x5ek' : 0xc0c00405,
    'at91sam9n12ek' : 0xc0c00405,
    'sama5d3xek' :0xc0902405,
    'sama5d3_xplained' : 0xc0902405,
    'sama5d4ek' : 0xc1e04e07,
    'sama5d4_xplained' : 0xc1e04e07
}


def _copyFiles ():
    ''' copies image files from source to the destination'''
    global gMemSetup

    for (k, ms) in gMemSetup.items():
        if ms.sf is not None: 
            print("copy {k}".format(k=k))
            shutil.copy(os.path.join(gSourceDir, ms.sf), os.path.join(gDestDir, ms.df))

def _genUBootCfg ():
    global gMemSetup
    global gSourceDir
    global gDestDir

    print("generate u-boot config")

    bootCfgStr = "bootcmd=nand read 0x{dtbLoadAddr:X} 0x{dtbAddr:X} {dtbSize}; nand read 0x{kernelLoadAddr:X} 0x{kernelAddr:X} {kernelSize}; bootz 0x{kernelLoadAddr:X} - 0x{dtbLoadAddr:X}".format(
            dtbLoadAddr=0x21000000,
            dtbAddr=gMemSetup['dtb'].add,
            dtbSize=os.path.getsize(os.path.join(gSourceDir, gMemSetup['dtb'].sf)),
            kernelLoadAddr=0x22000000,
            kernelAddr=gMemSetup['kernel'].add,
            kernelSize=os.path.getsize(os.path.join(gSourceDir, gMemSetup['kernel'].sf))
        )

    bootVars = (
        'bootdelay=0',
        'baudrate=115200',
        'stdin=serial',
        'stdout=serial',
        'stderr=serial',
        'bootargs=console=ttyS0,115200 mtdparts=atmel_nand:256k(bootstrap)ro,512k(uboot)ro,256k(env),256k(env_redundant),256k(spare),512k(dtb),6M(kernel)ro,-(rootfs) rootfstype=ubifs ubi.mtd=7 root=ubi0:rootfs rw',
        bootCfgStr
        )

    cfgMemCfg = bytearray(0x20000-5)
    l = len(cfgMemCfg)
    indx = 0
    for v in bootVars:
        l = len(v)
        cfgMemCfg[indx:indx+l] = v.encode('utf-8')
        indx += l + 1

    crc = binascii.crc32(cfgMemCfg)

    with open(os.path.join(gDestDir, gMemSetup['ubootEnv'].df), mode='wb') as f:
        # crc32 as little endian
        f.write(struct.pack('<I',crc))
        f.write(bytearray(1))
        f.write(cfgMemCfg)
        f.close()

def _helper_genTCLFilename (idName):
    pstr = os.path.join(gTCLfilepath ,gMemSetup[idName].df)
    pstr = pstr.replace('/', '\\')
    return pstr.replace('\\', '\\\\')

def _genFlashScript():
    global gMemSetup
    global gECCcnfg
    global gTCLfilename
    global gDestDir
    global gArch

    print("generate tcl script for sam-ba")

    tclStr = """puts "-I- start flashing"
NANDFLASH::Init
NANDFLASH::NandHeaderValue HEADER 0x{pmeccConfig:X}
NANDFLASH::EraseAllNandFlash
NANDFLASH::SendBootFilePmeccCmd "{bootstrapFile}"
send_file {{NandFlash}} "{ubootFile}" 0x{ubootAddr:X} 0 
send_file {{NandFlash}} "{ubootEnvFile}" 0x{ubootEnvAddr:X} 0
send_file {{NandFlash}} "{ubootEnvFileRed}" 0x{ubootEnvAddrRed:X} 0
send_file {{NandFlash}} "{dtbFile}" 0x{dtbAddr:X} 0
send_file {{NandFlash}} "{kernelFile}" 0x{kernelAddr:X} 0
NANDFLASH::NandSetTrimffs 1
send_file {{NandFlash}} "{rootfsFile}" 0x{rootfsAddr:X} 0
puts "-I- finished flashing"
""".format(
    pmeccConfig=gECCcnfg[gArch],
    bootstrapFile=_helper_genTCLFilename('bootloader'),
    ubootFile=_helper_genTCLFilename('uboot'),
    ubootAddr=gMemSetup['uboot'].add,
    ubootEnvFile=_helper_genTCLFilename('ubootEnv'),
    ubootEnvAddr=gMemSetup['ubootEnv'].add,
    ubootEnvFileRed=_helper_genTCLFilename('ubootEnvRed'),
    ubootEnvAddrRed=gMemSetup['ubootEnvRed'].add,
    dtbFile=_helper_genTCLFilename('dtb'),
    dtbAddr=gMemSetup['dtb'].add,
    kernelFile=_helper_genTCLFilename('kernel'),
    kernelAddr=gMemSetup['kernel'].add,
    rootfsFile=_helper_genTCLFilename('rootfs'),
    rootfsAddr=gMemSetup['rootfs'].add
    )

    with open(os.path.join(gDestDir, gTCLfilename), mode='w') as f:
        f.write(tclStr)
        f.close()


class _CLIError(Exception):
    '''Generic exception to raise and log different fatal errors.'''
    def __init__(self, msg):
        super(_CLIError).__init__(type(self))
        self.msg = "E: %s" % msg
    def __str__(self):
        return self.msg
    def __unicode__(self):
        return self.msg

def main(argv=None): # IGNORE:C0111
    '''Command line options.'''
    global gSourceDir
    global gDestDir
    global gTCLfilepath

    if argv is None:
        argv = sys.argv
    else:
        sys.argv.extend(argv)

    program_name = os.path.basename(sys.argv[0])
    program_version = "v%s" % __version__
    program_build_date = str(__updated__)
    program_version_message = '%%(prog)s %s (%s)' % (program_version, program_build_date)
    program_shortdesc = __import__('__main__').__doc__.split("\n")[1]
    program_license = '''%s

  Created by Stefan Jaritz on %s.
  Copyright 2016 organization_name. All rights reserved.

  Licensed under the Apache License 2.0
  http://www.apache.org/licenses/LICENSE-2.0

  Distributed on an "AS IS" basis without warranties
  or conditions of any kind, either express or implied.

USAGE
''' % (program_shortdesc, str(__date__))

    try:
        # Setup argument parser
        parser = ArgumentParser(description=program_license, formatter_class=RawDescriptionHelpFormatter)
        parser.add_argument("-s", "--source", dest="srcD", help="source path of the images [default: %(default)s]", default=os.getcwd())
        parser.add_argument("-d", "--destination", dest="dstD", help="destination where the images and the flash script is copied [default: %(default)s]", default=os.getcwd() )
        parser.add_argument("-t", "--tclFilePath", dest="tclD", help="TCL script path. The path where the TCL file gona be located [default: %(default)s]", default='' )
        parser.add_argument('-V', '--version', action='version', version=program_version_message)

        # Process arguments
        args = parser.parse_args()
        gSourceDir = args.srcD
        gDestDir = args.dstD
        gTCLfilepath = args.tclD

        shutil.rmtree(gDestDir, ignore_errors=True)
        os.makedirs(gDestDir)
        print("start")

        _copyFiles()
        _genUBootCfg()
        _genFlashScript()

        print("finished")
        return 0
    except KeyboardInterrupt:
        ### handle keyboard interrupt ###
        return -1
    except Exception as e:
        indent = len(program_name) * " "
        sys.stderr.write(program_name + ": " + repr(e) + "\n")
        sys.stderr.write(indent + "  for help use --help")
        return -2

if __name__ == "__main__":
    sys.exit(main())

III.) 创建自己的包

yocto-layer create own
bitbake-layers add-layer "../meta-own"

修改example.bb

SRC_URI = "file://testFTP.c"

S = "${WORKDIR}"

DEPENDS ="curl"

do_compile() {
    ${CC} testFTP.c -o testFTP ${CFLAGS} -lcurl 
}

do_install() {
    install -d ${D}${bindir}
    install -m 0755 testFTP ${D}${bindir}
}

现在添加“layer.conf”

IMAGE_INSTALL_append = " vim testftp"

现在 vim 编辑器和包含 testFTP 二进制文件的 testftp 配方安装在 rootfs 的“user/bin”中。

刷机后，启动SAMA5D35评估板。以“root”身份登录。输入:“testFTP”或“vim”并享受输出。

干杯!