Hello Hatim,
On Saturday 26 February 2011 05:04 PM, Hatim Ali wrote:
Hello,
I was trying to understand how NAND-SPL works. What I could understand after seeing the code is that
- NAND-SPL is a standalone application which will load the U-boot in the main memory.
- After doing the clock and DRAM initialization it will relocate itself in the DRAM.
- Then it will copy the u-boot from the nand into the RAM and execute the u-boot.
If my understanding is proper, then I have one doubt
- Since the nand_spl is making use of the same Start.S and lowlevel_init.S, the u-boot code will also perform relocation? So is it not a overhead doing relocation twice?
As Albert mentioned in another mail, image copying and relocation can be suppressed by using your linked address as the target address when you call relocate_code.
This is easier to achieve in SPL because we have a custom and simpler board_init_f. This is much more difficult to achieve in regular U-Boot because the target address is calculated at run-time in board_init_f and also depends on the U-Boot size.
Also is there any similar implementation for MMC-SPL?
You might want to have a look at the series I posted yesterday for OMAP4. Please note that relocation and image copying has been suppressed in this SPL.
Br, Aneesh