On Fri, 18 Mar 2011 12:43:06 +0100 <[email protected]> wrote: > > Hi all, > I have some questions about the bad block management in the NAND-driver, I > hope this is the right place to ask this: > > The things I believe to know, please correct me, if its wrong: > If > I have a new NAND-Flash, the manufacturer marked the bad block in the > spare area/OOB (normaly good blocks are marked as 0xFF in the first 2 > bytes?). > The u-boot scans for these bad blocks and saves the information in the bbt. > > What > happens, if a block gets worn out? Would this block only be markes as > bad in the bbt, or would this information would be also stored in the > spare area (the driver write another value, not 0xFF in the firts 2 > bytes?).
As long as you have an in-flash bbt, it only gets marked in the bbt. If you don't have an in-flash bbt, an OOB bad block marker is written. > Is it possible to restore the bad block informations, if the > whole nand-flash would be erased (for example by writing 0 in all block > and after this by erasing the blocks and check the error status bit of > the NAND-flash device)? It's possible to do your own testing and mark blocks bad as a result, but you're not really restoring the original information. The manufacturer may have used a more rigorous test. > If yes, is such a function implemented in u-boot? No. You should avoid clearing manufacturer-set bad block markers. -Scott _______________________________________________ U-Boot mailing list [email protected] http://lists.denx.de/mailman/listinfo/u-boot
