User`s guide

Porting U-Boot from an i.MX53 Reference Board to an i.MX53 Custom Board
i.MX53 System Development User’s Guide, Rev. 1
Freescale Semiconductor 11-3
coded in the DCD table, inside the boot header of the U-Boot image. When porting bootloader, kernel or
driver code, you must have the schematics easily accessible for reference.
11.3.1 Changing the DCD Table for i.MX53 DDR3 Initialization
Initializing the memory interface requires configuring the relevant I/O pins with the right mode and
impedance and initializing the ESDCTL module.
1. To port to the custom board, the appropriate DDR initialization needs to be used. This is the same
initialization as would be used in a JTAG initialization script.
2. Open the file board/freescale/mx53_<custom board name>/flash_header.S
3. Modify all MXC_DCD_ITEM macros to match the memory specifications.
This is the new board/freescale/mx53_<custom board name>/flash_header.S customized for DDR3.
NOTE
If you change the number of MXC_DCD_ITEM lines in the DCD table, you
must update the value of the dcd_hdr and write_dcd_cmd labels according
to the number of items.
11.3.2 Booting with the Modified U-Boot
If the DCD table (board/freescale/mx53_<custom board name>/flash_header.S) was modified
successfully, you can compile and write u-boot.bin to an SD card. To test this, insert the SD card into the
SD card socket of the CPU board and power cycle the board.
A message like this should be printed in the console:
U-Boot 2009.08 (Jul 29 2010 - 15:17:24)
CPU: Freescale i.MX53 family 1.0V at 800 MHz
Board: Unkown board id1:11
Boot Reason: [POR]
Boot Device: SD
I2C: ready
DRAM: 1 GB
MMC: FSL_ESDHC: 0, FSL_ESDHC: 1
Card did not respond to voltage select!
MMC init failed
In: serial
Out: serial
Err: serial
Net: FEC0
<reference board name>: U-Boot >
11.3.3 Further Customization at System Boot
To further customize your U-Boot board project, use the first function that system boot calls on:
start_armboot in "lib_arm/board.c".
board_init()