How to configure Yocto for an example "hello world" program which uses a Debian library? - linux

Question

I build a simple software in my Debian VM. It tries the download a file from a FTP server. For that I use the libcurl library(libcurl-openssl-dev).
Now I have a SAMA5D3x-Evalboard available. For self education purpose I like to build a Linux + Toolchain for it. I found the Yocto project. The meta layer concept seems to be good approach for managing different platforms - so let's try it!
I found some examples at the net. But no which covers the combination of "hello world" + bigger lib.
I want:
get the X-compile toolchain + Linux image(includes my hello world + the libcurl shared objects)
My approach:
meta-atmel: for the SAMA5D3x eval board
meta-debian: for the lib "libcurl-openssl-dev"
meta-mySoftware: for the hello world program
The constrains are:
main.c - name of the hello world program
libcurl - c lib name (I have chosen this lib, because it has a lot of dependencies)
How to setup it right? If there are better ideas they are welcome!

Answer 1

Installation & Configuration of Yocto
I.) install toolchain
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.) opt. configure git after proxy
git config --global core.gitproxy <gitproxy>
I.3.) download Toolchain + meta packages and checkout the "right" commit
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.) build kernel+rootfs for SAMA5D3x
II.1) create new project
source oe-init-build-env
the new project is created at the "build" dir
modify layers "conf/bblayers.conf" via commandos
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"
edit of "conf/local.conf"
MACHINE ??= "sama5d3xek"
DL_DIR ?= "${TOPDIR}/../downloads"
DISTRO ?= "poky-atmel"
the download directory is outside of the build environment. The downloaded sources can be used for different builds.
II.2) create image
bitbake -c clean core-image-minimal
bitbake core-image-minimal
the result files are created at "tmp/deploy/images/sama5d3xek"
II.3) flash image
The sam-ba tool from Atmel is needed. The Flash-Process can be automated by a script(we create a tcl file). The self written tool "buildAtmelImages.py" copies the needed image files for the SAMA5D35, creates the u-boot configuration and a Flash-Script. An Example:
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"
here comes the code for "buildAtmelImages.py":
#!/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.) Create own package
yocto-layer create own
bitbake-layers add-layer "../meta-own"
modify the 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}
}
now add in "layer.conf"
IMAGE_INSTALL_append = " vim testftp"
Now the vim editor and the testftp recipe, which includes the testFTP binary is installed at the "user/bin" at the rootfs.
After the flashing, start the the SAMA5D35 Evalboard. Login as "root". Type: "testFTP" or "vim" and enjoy the output.
Cheers!