On Wed, 2014-02-05 at 15:16 +0100, Michal Simek wrote:
On 02/04/2014 09:46 PM, Scott Wood wrote:
On Tue, 2014-02-04 at 13:43 +0100, Michal Simek wrote:
Hi Scott and others,
I have a question regarding BBT position and number of blocks allocated for BBT.
Did you face the issue with last 4 blocks broken in any NAND flash device since the default option in Linux/u-boot BBM is last 4 blocks?
It doesn't mean that if the last 4 blocks are broken than the NAND flash device is broken too. Also I haven't seen any common binding for Linux kernel to change it.
Has someone tried to improve this algorithm or process of storing BBT in a better way. For example just look for BBT from the end till any limit?
I don't recall if I've ever tested it personally, but that sort of scanning is already there. Have you seen a problem with it?
We have met with nand device which has broken last 4 blocks and u-boot and linux just scan last 4 blocks by default.
In connection to Linux. Interesting is that there is no binding for extending scan blocks and this has to be done through driver properties.
Could you be more specific about what sort of "driver property" you're talking about? AFAICT from glancing at the code, searching is the default unless the controller driver specifies NAND_BBT_ABSPAGE.
In any case, this code comes straight from Linux, so you'll probably find people more familiar with this code on linux-mtd.
-Scott