In message 50c9a225050619183868b48c13@mail.gmail.com you wrote:
in vivi if can use bon to set partitionsand in DULG Manual i see something like "root=/dev/mtdblock2" in BOOTARGS.but i can't find the defination of mtd partition in /board/smdk2410/smdk2410.c or smdk2410.h.and i wonder whether i must set "root=/dev/mtdblockX" in my BOOTARGS or i can just set the physical address of root-cramfs in NAND flash?
What exactly is your question? The subjet says that your ramfs image is in RAM, but now you say it's in NAND flash?
To access NAND flash you must always provide a /dev/mtdblock? device, which means you must define a partition map. How you do this - i. e. by using a static map or a command line option - is up to you. How to make Linux find your NAND flash is a question which is off topic here.
Best regards,
Wolfgang Denk