Supporting flash that powers up locked

[David Woodhouse]

On Tue, 2004-11-23 at 14:25 -0800, Todd Poynor wrote:
> Flash chips that power up with all blocks locked (such as K3
> StrataFlash) seem to be showing up on more and more platforms.  At the
> risk of being a pest, I'd like to push for some agreement on how to
> handle this and possibly get the support into linux-mtd.
> 
> Below is a patch to the partition driver to use the partition map as the
> source of information for whether a partition is to be writeable and to
> unlock blocks upon write if the block is found to be locked when this
> was not intended.  It intercepts an EROFS return from the chip driver on
> a write/erase, unlocks blocks, and retries the write/erase, if the
> partition is marked writeable.  If the partition is not writeable, or if
> the partition has been explicitly locked, then the locked blocks are
> left alone and the EROFS is returned to the caller.

We already have a bit to set in the partition flags to show that a
partition should be read-only. 

I'd rather do this with a blacklist of the chips which lock themselves,
and have the chip driver automatically unlock it at boot time and
suspend time (or automatically as required).

-- 
dwmw2