[PATCH][MTD][NAND]Bad Block Management

[Ricard Wanderlof]

On Wed, 27 Aug 2008, Zhao Shengzhe-a18689 wrote:

> The bad blocks will be detected by low-level hardware driver. The NAN 
> devices have a Status Register that indicates whether an operation is 
> successful or not. Additional Bad Blocks are identified when attempts to 
> program or erase give errors in the Status Register. Since our patch is 
> in MTD layer, so you cannot find the codes for detecting bad blocks.

OK.

When I ran some tests on an ST 256 MiB flash a while ago, I got the 
impression that by the time the status register indicates a problem, the 
block has been worn out (in the sense that subsequent reads are not 
reliable) for quite a while. So another approach would be to keep track of 
the amount of read errors encountered, together with the number of times 
the block has been rewritten due to excessive read errors. I'm not sure if 
UBI does this though if one wants that level of reliability.

/Ricard
--
Ricard Wolf Wanderlöf                           ricardw(at)axis.com
Axis Communications AB, Lund, Sweden            www.axis.com
Phone +46 46 272 2016                           Fax +46 46 13 61 30