NAND defect Block handling

[Sascha Hauer]

Hi Jürgen,

On Fri, May 25, 2012 at 09:35:54PM +0200, Jürgen Kilb wrote:
> Hi,
> I discovered a problem which I thought would be handled in a different way..
> During "tftp 250Mbyte_Testimage.bin /dev/nand0.rootfs.bb" an I/O error occurred
> and tftp stopped downloading/writing the file to the nand0.rootfs.bb partition.
> 
> ===
> ...###################################write: I/O error
> 
> tftp failed: error -5
> ===
> 
> As far as I debugged the problem, a block erase error occurred. I thought the
> normal behavior should be, mark the defect block as bad and continue with 
> the next block.
> 
> What is the best way to handle such problems?
> 
> - implement such a behavior if the destination is a *.bb device
> - add a nand_write command
> - add a global option to mark a bad nand block

We have a command for this: nand -b

I think the best was would be to automatically mark a block as bad when
it occurs. It should be configurable during runtime though so that we
can activate it once we know a driver is actually working. Otherwise
many developers end up with 100% bad blocks on their nand devices.

Sascha

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