Linux Kernel burning and writing

During the Linux kernel porting process, you need to burn the Linux kernel to the Development Board.

 

The basic steps are as follows:

1, the bootloader through the J-TAG burned to the Development Board, and the general Bootloader and hardware are closely related, hardware manufacturers will provide such a board-level support package.

Different bootloaders provide different bootloader commands, which can be viewed through help.

 

2. Transmit the Linux kernel to ram through TFTP. Note that in the development environment of host machine-Development Board, the PC host acts as a TFTP server, because the Linux kernel is downloaded to the Board through a PC, the Development Board acts as a TFTP client. In order to establish a connection to the TFTP protocol, the IP address of the host is usually set to be in the same network segment as the IP address of the Development Board. the IP address of the Development Board can generally be completed through the bootloader command.

 

For example, the TFTP transmission command is TFTP zimage. Then the download starts.

The principle is as follows: after the TFTP Command is written, the Development Board sends a TFTP request to the TFTP server software (installed on the PC end). After the TFTP server responds, download the data to the Development Board. In this process, the first step is to put the downloaded image file in Ram, that is, the memory. In order to enable the next startup of the kernel, you do not have to download it again, you need to burn the image file to permanent storage, such as nandflash, so that the image file can be read from nandflash to the memory at the next startup. Generally, bootloader provides commands such as nandwrite for writing to flash, generally, the required parameters are the starting address of the image file in the memory, the starting address burned to flash, and the actual file size (this is usually displayed after the image is downloaded to the memory ).

 

3. During Android kernel transplantation, you also need to download some other file system images to the Development Board, such as the root file system (rootfs) and system file system ). The method used is basically the same as the kernel burning process.

 

During the writing process, the following software is generally used:

TFTP server software, terminal software, J-TAG software.