Different erase block sizes in a JFFS2 partion.

Joakim Tjernlund Joakim.Tjernlund at transmode.se
Fri Sep 29 02:43:36 EDT 2006


Josh Boyer wrote:
> On 9/28/06, Joakim Tjernlund <joakim.tjernlund at transmode.se> wrote:
>> Got multiple NOR chips with top and bottom boot blocks with diffrent EB size
>> then the rest of the blocks.
> 
> Intel P30?  IIRC, the MTD driver maps those into a set of larger
> virtual eraseblocks.  You might not be able to even distinguish that
> they exist.

yes, Intel P30.
The cfi_cmdset_0001 driver maps them like this:
0: offset=0x0,size=0x8000,blocks=4
1: offset=0x20000,size=0x20000,blocks=255
2: offset=0x2000000,size=0x8000,blocks=4
3: offset=0x2020000,size=0x20000,blocks=255

First, this map is wrong. 2: and 3: should be swapped, that is,
the small blocks should be at the end of the device.

the small blocks fits into a larger one so I should have no problem reading/writing
to such virtual block, but I don't think erase will work as JFFS2 will
only erase one of the small blocks instead of all 4. Maybe I am missing something?




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