The startup process of the S5PV210 microprocessor

      When S5PV210 is powered on, it will execute the solidified boot code BL0 from IROM, which initializes the clock, determines the boot device, and copies BL1 (maximum 16KB) from the boot device to IRAM (address 0xD0020000, where the 16 bytes before 0xD0020010 store the check information and size of BL1), and checks BL1. After the check is successful, it will be transferred to BL1 for execution.

      BL0: refers to the boot code solidified in the IROM of the S5PV210 microprocessor.

      BL1: refers to the first 16kB code of the uboot.bin binary file automatically copied from the external memory (nand/sd/usb) in IRAM.

      BL2: refers to the complete code of UBOOT executed in memory after redirection in the code.

     The relationship between the above three is: BL0 loads BL1 into IRAM, then BL1 runs in IRAM and loads BL2 into SDRAM, and BL2 loads the embedded operating system kernel. BL is the abbreviation of bootloader.

     The address range of the IRAM of the S5PV210 microprocessor is 0xD0020000~0xD003FFF. After power-on, the stubborn BL0 is executed, and the code of the boot device is copied to the IRAM and jumped to 0xD0020010 for execution.

     The 16-byte header information from 0xD0020000 to 0xD0020010 is arranged as follows:

     0x0 address: BL1 size

     0x4 address: must be set to 0;

     0x8 Address: CheckSum.

     0xc address: must be set to 0.

     I summarize the flowchart of the header operation as follows: