[PATCH 13/22] remove erase regions

Christopher Hoover ch at murgatroid.com
Tue Dec 21 16:09:12 EST 2004

>From Jörn Engel [mailto:joern at wohnheim.fh-wedel.de] - 
> On Tue, 21 December 2004 10:42:07 -0800, Christopher Hoover wrote:
> > >From Jörn Engel -
> > > I see absolutely no reason for complicated erase reagions.  On the
> > > user side, everyone but mtdchar effectively ignores it anyway.
> > 
> > I don't grok this.   What about flash with variable-sized 
> blocks?  (I have a
> > board with such flash and code that uses eraseregions.)
> Sure, from AMD or some other compatible manufacturer.  The
> variable-sized blocks were nice until there were better solutions to
> the problem, like jffs2.  Jffs2 exists, so they are largely useless.

Intel C3 flash, too.

> 5. mtdchar

This is an important case.  

The reason embedded systems use flash with variable sized blocks is for (in
the small blocks) parameter stores for bootloaders and applications.

I've got several deployed systems that use this technique.  I've seen at
least one other.

> 5 does, but is horribly ugly and noone cares enough to clean it up. 

This is not a reason to toss it.  We don't capriciously break user space
interfaces in Linux.

Also this:

6. The hook that unlocks locked-on-power-up flash, such as (*surprise*) C3
flash.  It needs to call unlock with the start address of each block.  It
needs eraseergions to do that.


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