Thank you for your answer. But as you said in the letter, "NOR can be mapped in its entirety, while with NAND only the first 4KiB gets
mapped, and that code has to fetch the rest of u-boot from NAND and copy it to RAM before continuing." Why did you also mentioned that there is no need to modify the start.s, isn't there any difference between booting from NOR and NAND for start.s?

On Fri, May 16, 2008 at 02:54:34PM +0800, jiale.Yin wrote:

> Our board is reference with the mpc8313erdb,and its design is to link CS0

> to the NAND FLASH, so I have to boot from NAND other than NOR.In

> /board/mpc8313erdb I can find some files, such as nand_boot.c, nand.c and

> nand_ecc.c,

I assume you're talking about the Freescale BSP, as those files are not in

mainline u-boot.

> which I think are related with booting from NAND.What I want

> to know is if booting from NAND,is there any need to modify the start.s

No, beyond what's already been changed in the BSP to support it. Make sure

you use a NAND configuration when building u-boot.

> and what is needed to ba added. What's the difference between NOR-BOOT and

> NAND-BOOT. Thank you!

NOR can be mapped in its entirety, while with NAND only the first 4KiB gets

mapped, and that code has to fetch the rest of u-boot from NAND and copy it

to RAM before continuing.

-Scott