[U-Boot-Users] das u-boot and disc on chip
wd at denx.de
Wed Mar 2 23:00:15 CET 2005
in message <42262F9B.7030509 at orkun.us> you wrote:
> I 100% agree that dealing with a separate NOR boot ROM is so much more
> easier. However, I also see booting from NAND data flash with a small
> boot readable sector is quickly becoming popular in lower cost/smaller
> footprint/less power consumption equipment.
Yes - and you shift 90% of the problems that U-Boot is supposed to
solve (like easy debugging of the low level initialization sequence)
into this "small primary bootstrap loader".
> IMHO instead of denying this reality, perhaps we (as U-Boot
I don't deny it. I just tend to ignore it - like I ignore systems
running (or crashing) those Windoze "software" ;-)
> developers/users) should make some enhancements to deal with this
> situation in a formal supported way before too many forks occur.
Actually NO enhancements are needed. All is ready and in place, it's
just that you don't get any support here for creating the primary
bootstrap loader. This is a different issue, which is unrelated to
U-Boot. U-Boot can live with suh a situation fine - of course you
have to know _exactly_ what you are doing. See for examplethe Atmel
AT91RM9200 configuration where all you need to change is the
CONFIG_BOOTBINFUNC definition to either use an external bootstrap
loader or to have a real self-contained U-Boot image.
U-Boot was defined to solve certain problems that are typical for
board bringup; this worked pretty well - just see how many relatively
unexperienced developers were able to port U-Boot to their hardware.
If you force U-Boot into a hostile environment, the same old problems
will have to be solved again - there is nothing U-Boot can do to
prevent this. So if you go that route, please don't expect to find
much help here on this list.
Software Engineering: Embedded and Realtime Systems, Embedded Linux
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
That was the thing about deserts. They had their own gravity. They
sucked you into the centre. - Terry Pratchett, _Small Gods_
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