On Mon, 2013-11-25 at 08:52 -0300, Ezequiel Garcia wrote: > > Your understanding is correct: NAND *must* be erased explictly in > userspace > before writing. However, keep in mind the following additional > constraints: > > * Writing should be always performed using 'nandwrite', > not tools such as 'cat' or 'dd'. > > * An mtdblock shouldn't be used to access directly the NAND from > userspace. AFAICS, the primarily usage of mtdblock is to be able to > mount JFFS2.
No. You don't need mtdblock to mount JFFS2 at all. The mtdblock driver was used in the *very* early days of the MTD system, on NOR flash with a "traditional" file system. Either in read-only mode for something like cramfs, or in a very unsafe writeable mode. We actually put ext2 on it for the Compaq iPaq for a while, before we had JFFS. It was used as a shortcut for mounting JFFS2, and still is by a lot of people, but it's certainly not necessary. You can turn off CONFIG_BLOCK entirely and still use JFFS2. You should consider mtdblock to be the most basic, primitive, "flash translation layer" that can possibly exist. And thus, should basically never use it. I certainly don't approve of trying to extend it. -- dwmw2
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