Messages in this thread | | | Date | Fri, 16 Dec 2011 10:44:06 +0800 | From | LiuShuo <> | Subject | Re: [PATCH 3/3] mtd/nand : workaround for Freescale FCM to support large-page Nand chip |
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于 2011年12月15日 04:15, Scott Wood 写道: > On 12/14/2011 02:41 AM, LiuShuo wrote: >> 于 2011年12月13日 10:46, LiuShuo 写道: >>> 于 2011年12月13日 05:30, Scott Wood 写道: >>>> On 12/12/2011 03:19 PM, Artem Bityutskiy wrote: >>>>> On Mon, 2011-12-12 at 15:15 -0600, Scott Wood wrote: >>>>>> NAND chips come from the factory with bad blocks marked at a certain >>>>>> offset into each page. This offset is normally in the OOB area, but >>>>>> since we change the layout from "4k data, 128 byte oob" to "2k >>>>>> data, 64 >>>>>> byte oob, 2k data, 64 byte oob" the marker is no longer in the >>>>>> oob. On >>>>>> first use we need to migrate the markers so that they are still in >>>>>> the oob. >>>>> Ah, I see, thanks. Are you planning to implement in-kernel migration or >>>>> use a user-space tool? >>>> That's the kind of answer I was hoping to get from Shuo. :-) >>> OK, I try to do this. Wait for a couple of days. >>> >>> -LiuShuo >> I found it's too complex to do the migration in Linux driver. >> >> Maybe we can add a uboot command (e.g. nand bbmigrate) to do it, once is >> enough. > Any reason not to do it automatically on the first U-Boot bad block > scan, if the flash isn't marked as already migrated? > > Further discussion on the details of how to do it in U-Boot should move > to the U-Boot list. > >> And let user ensure it been completed before linux use the Nand flash chip. > I don't want to trust the user here. It's too easy to skip it, and > things will appear to work, but have subtle problems. > >> Even if we don't do the migration, the bad block also can be marked as bad >> by wearing. So, do we really need to take much time to implement it ? >> (code looks too complex.) > It is not acceptable to ignore factory bad block markers just because > some methods of using the flash may eventually detect an error (possibly > after data is lost -- no guarantee that the badness is ECC-correctable) > and mark the block bad again. > > If you don't feel up to the task, I can look at it, but won't have time > until January. hi Scott, It's really hard to me and I have much other works to do now. Thanks for your help.
hi Artem, Could this patch be applied now and we make a independent patch for bad block information migration later?
-LiuShuo
> -Scott
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