[U-Boot] How to prepare a MTD partion?

Hi,

After defined MTD partions in kernel and u-boot, what's the next steps to make it mountable?

I have defined two data partitions in MTD out of my NAND flash, each of which has size of about 800M. Then I want to make them as Yaffs2 and j2ffs and mount them to use.

In PC linux, I know there are something like mkfs.xxx, which seems not the case for MTD partitions. So, can anyone be so kind to tell me what are steps I need to do in u-boot and out-of-uboot?

Thanks in advance!