Turn: am335x START process

Links: http://blog.csdn.net/hudaweikevin/article/details/10376585 David_hu

Boot order (for TI OMA3 EVM)

The general boot order for Linux is:

• BOOT ROM
• X-loader
• U-boot
• Linux

When power is on, the boot of the OMAP device starts from the boot ROM inside the CPU, and this part of the code is cured at the time of the factory and cannot be changed. The boot ROM looks for the first external bootloader by reading the configuration of the external boot pin. The devices you can look for are NAND, UART, SD/MMC. Once the first loadable external device is found, the CPU loads a piece of code for the external device (the file name that we now use for the platform is generally called MLO), which is called X-loader. X-loader also can be modified by everyone. X-loader will be executed after the U-boot, also called the second boot.

The main functions of u-boot are:

1 is the kernel loaded from an external device into memory, the source of the U-boot loading kernel is: NAND, Sd/mmc Card, UART or Ethernet (via TFTP).

2 is to provide the location of the file system required by the kernel, u-boot specified root file system location: NAND (JFFS2), SRAM (RAMDisk), SD/MMC card (ext3 partition) or mounted over IP (NF S

After U-boot starts the Linux kernel, the kernel then loads the root file system.

Turn: am335x START process