From: Jamie Lokier <jamie@shareable.org>
To: Holger Schurig <hs4233@mail.mn-solutions.de>
Cc: "Jörn Engel" <joern@logfs.org>, linux-mtd@lists.infradead.org
Subject: Re: CFI-0002 NOR flash blocking CPU on status register reads
Date: Tue, 10 Jun 2008 14:59:51 +0100 [thread overview]
Message-ID: <20080610135951.GB31112@shareable.org> (raw)
In-Reply-To: <200806101548.40059.hs4233@mail.mn-solutions.de>
Holger Schurig wrote:
> > Won't the CPU read the initial boot instructions from this
> > flash, get programming status bytes instead of CPU
> > instructions, and thus get confused?
>
> The bootloader could/should make sure that every block is in the
> correct state for Linux.
Even the bootloader cannot start, if the flash is not in the correct
programming state - even though bootloader partition is not touched.
(The bootloader instructions are temporarily replaced by garbage while
programming _any_ blocks.)
However, see my other reply. If the board's reset signal is wired to
the flash, it should force the flash into a suitable state prior to
reading the bootloader. I have to check if they wired the reset
signal properly: these schematics have too many zero-ohm links which
might be there or not on manufactured boards.
-- Jamie
next prev parent reply other threads:[~2008-06-10 13:59 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-06-10 13:09 CFI-0002 NOR flash blocking CPU on status register reads Jamie Lokier
2008-06-10 13:48 ` Holger Schurig
2008-06-10 13:59 ` Jamie Lokier [this message]
2008-06-10 13:52 ` Jamie Lokier
2008-06-10 17:18 ` Trent Piepho
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