(Yocto) How to create your own meta-layer?

(Yocto) How to create your own meta-layer?

Table of contents generated with markdown-toc

1. DESCRIPTION

In this project, I will show you how to create your own meta-layer by yocto, bitbake command. This project is the result by following the course below, which is fit for the developer who has basic acknowledge of yocto.

2. Steps

2.1. Environment

Use the command source <path_t_poky_oe-init-build-env>, which will give you the environment needed.

2.2. Layer Creation

Use bitbake-layers create-layer <path_you_want_to_put_your_layer> to create the layer.
Then you will find the folder as below with the tree command. It means that your creation is successful.

├── conf
│   └── layer.conf
├── COPYING.MIT
├── README
└── recipes-example
    └── example
        └── example_0.1.bb

2.3. Layer Addition

Use the command bitbake-layers add-layer <path_of_your_layer>
And then you will fould in the conf/bblayers.conf, your layer was added into the list. If you build the image now, it will be built successfully with an empty layer.

BBLAYERS ?= " \
  /yocto/poky/meta \
  /yocto/poky/meta-poky \
  /yocto/poky/meta-yocto-bsp \
  /yocto/poky/meta-raspberrypi \
  /yocto/poky/meta-test-layer \
  "

2.4. Application Creation

2.4.1. You could add your own recipe in the recipes-example or create a new recipe with the same structure of recipes-example

cd recipes-example
mkdir test_hello
cd test_hello
mkdir hello
touch hello.bb
mkdir hello2
touch hello2.bb
cd hello
touch hello.c
touch Makefile

.
├── conf
│   └── layer.conf
├── COPYING.MIT
├── README
└── recipes-example
    ├── example
    │   └── example_0.1.bb
    └── test_hello
        ├── hello
        │   ├── hello.c
        │   └── Makefile
        ├── hello2
        │   ├── hello.c
        │   └── Makefile
        ├── hello2.bb
        └── hello.bb
# ps: the folder name and the name of the .bb file should be the same.

2.4.2. Put the following content in the hello.bb file.

DESCRIPTION = "Hello World"
SECTION = "libs"
LICENSE = "MIT"
PV = "1"
PR = "r0"

SRC_URI = "\
file://hello.c \
file://Makefile \
"
LIC_FILES_CHKSUM = "file://hello.c;md5=7b9ca335e1a89cba4c18bab96dcc6d8c"

do_compile() {
	make
}

# WORKDIR is a variable global, so if you use directly in the do_* operation, an error would be generated.
S = "${WORKDIR}"
do_install() {
	install -d ${D}${bindir}/
	install -m 0755 ${S}/hello ${D}${bindir}/
}

FILE_${PN} = "${bindir}/hello"
TARGET_CC_ARCH += "${LDFLAGS}"

2.4.3. Fill in the code and makefile to the .c and Makefile

// C++

#include "stdio.h"
#include "stdlib.h"
int main() {
	printf("hello world!!\n");
	return 0;
}

#Makefile

hello: hello.o
	$(CC) -o hello hello.o


hello.o: hello.c
	$(CC) -c hello.c

.PHONY: clean
clean:
	-rm -rf *.o

2.4.4. Check if the application was added successfully.

bitbake -s |grep hello

2.4.5. Build

bitbake hello

2.4.6. Add the application in the image. Find your <image.bb> file and add the app at the end of the IMAGE_INSTALL list.

IMAGE_INSTALL += " \
kernel-modules \
hello \
"

2.4.7. Build your image and you will find your app in the /usr/bin/.

3. All the content below is generated automatically.

This README file contains information on the contents of the meta-test-layer layer.

Please see the corresponding sections below for details.

Dependencies
============

  URI: <first dependency>
  branch: <branch name>

  URI: <second dependency>
  branch: <branch name>

  .
  .
  .

Patches
=======

Please submit any patches against the meta-test-layer layer to the xxxx mailing list (xxxx@zzzz.org)
and cc: the maintainer:

Maintainer: XXX YYYYYY <xxx.yyyyyy@zzzzz.com>

Table of Contents
=================

  I. Adding the meta-test-layer layer to your build
 II. Misc


I. Adding the meta-test-layer layer to your build
=================================================

Run 'bitbake-layers add-layer meta-test-layer'

II. Misc
========

--- replace with specific information about the meta-test-layer layer ---

FengD / meta-test-layer