Difference between revisions of "Embedded Linux system basis"
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==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== | ||
Revision as of 08:23, 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.
