Embedded Linux system basis: Difference between revisions
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An embedded Linux system is very similar (when speaking about software) to a Desktop one, thanks to the power of the latest embedded microprocessor, like the | An embedded Linux system is very similar (when speaking about software) to a Desktop one, thanks to the power of the latest embedded microprocessor cores, like the ARM9™/Cortex™ ones. | ||
It is composed of: | It is composed of: | ||
* a '''bootloader''', which is the first bits of code executed when the processor starts. It behaves like the BIOS+Grub combination on Desktop PCs. | * a '''bootloader''', which is the first bits of code executed when the processor starts. It behaves like the BIOS+Grub combination on Desktop PCs. | ||
* an operating system = the '''Linux kernel''' | * an operating system = the '''Linux kernel''' | ||
* many programs and librairies | * many programs and librairies organized in a filesystem = the '''rootfs''' | ||
==The bootloader== | ==The bootloader== | ||
In our case our bootloader is U-Boot. It's main role is to initialize the hardware, load the Linux kernel and launch it with the correct parameters | In our case our bootloader is [http://www.denx.de/wiki/view/U-Boot U-Boot]. It's main role is to initialize the hardware, load the Linux kernel and launch it with the correct parameters | ||
==The kernel== | ==The kernel== | ||
In our case | In our case [https://www.kernel.org/ Linux™]. | ||
==The rootfs== | ==The rootfs== | ||
It is composed of: | It is composed of: | ||
* a C library | * a C library (mostly uClibc or glibc in our boards), | ||
* basic utilities (in our case | * basic utilities (in our case regrouped as one executable through [[Busybox]]), | ||
* | * additional libraries and tools, | ||
==Build system / toolchain== | |||
To build all these tools, you need a "build system". We use [https://buildroot.org/ Buildroot]. | |||
# This system will build a gcc cross-toolchain that will allow to generate on your PC software that can be run on your APF. | |||
# When this toolchain is ready it will compile the bootloader, the kernel and the tools of the rootfs | |||
# Finally it will generate images of these 3 components that can be "flashed" on your APF/OPOS module | |||
ARM9 & Cortex are registered trademarks of [https://www.arm.com/ ARM Limited]. | |||
Linux is a registered trademark of Linus Torvalds. | |||
Latest revision as of 09:31, 22 November 2016
An embedded Linux system is very similar (when speaking about software) to a Desktop one, thanks to the power of the latest embedded microprocessor cores, like the ARM9™/Cortex™ ones. It is composed of:
- a bootloader, which is the first bits of code executed when the processor starts. It behaves like the BIOS+Grub combination on Desktop PCs.
- an operating system = the Linux kernel
- many programs and librairies organized in a filesystem = the rootfs
The bootloader
In our case our bootloader is U-Boot. It's main role is to initialize the hardware, load the Linux kernel and launch it with the correct parameters
The kernel
In our case Linux™.
The rootfs
It is composed of:
- a C library (mostly uClibc or glibc in our boards),
- basic utilities (in our case regrouped as one executable through Busybox),
- additional libraries and tools,
Build system / toolchain
To build all these tools, you need a "build system". We use Buildroot.
- This system will build a gcc cross-toolchain that will allow to generate on your PC software that can be run on your APF.
- When this toolchain is ready it will compile the bootloader, the kernel and the tools of the rootfs
- Finally it will generate images of these 3 components that can be "flashed" on your APF/OPOS module
ARM9 & Cortex are registered trademarks of ARM Limited.
Linux is a registered trademark of Linus Torvalds.
