Dear Cunsuo Guo, In message <AANLkTin=d7t-jqb4bfnyizpt8wbzx5kjy-fqyabyz...@mail.gmail.com> you wrote: > > > Why try to read from NAND to RAM in the relocation part of start.S, > > where you would not be able to use C or BSS variables? > > > > Because S3C2410 can _ONLY_ take the first 4KBytes into RAM (Basically some > hidden microcode in the S3C2410 takes care of copying the first 4KB of NAND > flash into RAM), so the rest code must be relocated into RAM from NAND by > the U-Boot code itself. Of course, there's no C environment set up yet, all > job should be done by assembly code.
This is not really different from how NAND booting works on many other boards. It is definitely not a reason to use assembly only. Instead, the standard nand_spl approach should be used. Best regards, Wolfgang Denk -- DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: w...@denx.de Documentation is like sex: when it is good, it is very, very good; and when it is bad, it is better than nothing. - Dick Brandon _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
