TQ2440 Study Notes —— 33. Porting the Linux Kernel [Preparation]

1. Linux versions and features

The Linux kernel version number can be found in the Makefile in the top-level directory.

VERSION = 2

VERSION = 6

SUBLEVEL = 22

EXTRAVERSION = .6

These lines make up the version number 2.6.22.6. VERSION and VERSION make up the major version number of the version. SUBLEVEL is the minor version number, and EXTRAVERSION is the extended version number. Linux kernel versions are divided into test versions and stable versions. VERSION values ​​that are even are stable versions, and VERSION values ​​that are odd indicate that new content has been added to the version, and the version is an unstable test type.

2. Linux Porting Preparation

1. Get the kernel source code

Log in to the official website of the Linux kernel http://www.kernel.org/, you can see the following content:

The meaning of each symbol:

To port and develop on Linux 2.6.22.6, you can first download Linux-2.6.22.6.tar.bz2 and then decompress it to get linux-2.6.22.6, which contains the kernel source code.

You can also download the kernel source file and then apply the patch.

3. Kernel source code structure

There are nearly 20,000 kernel files, which are located in 17 subdirectories under the top-level directory. Each directory has independent functions. The last two directories do not contain kernel code.

For the ARM architecture S3C2440, the system-related codes are in the arch/arm/ directory. When porting Linux later, the first step is to modify the files in this directory. The following figure shows the hierarchy of the kernel code.