[U-Boot-Users] [DNX#2006070742000028] [patch] add-support-for-high-boot-on-tqm5200-and-tqm5200s-boards

[Martin Krause]

Hallo Herr Denk,

wd at denx.de wrote on Saturday, July 08, 2006 6:41 PM:
> > The high boot U-Boot could be used as a backup or rescue option if
> > something goes wrong during an (low boot) U-Boot update. For this a
> > secondary copy of U-Boot is stored at the end of the flash memory.
> > Over jumper X30 on the STK52xx the desired boot option (low boot or
> > high boot) could be selected. 
> > 
> > Hint: the CPLD on the TQM5200 must be programmed with a software
> > version supporting the high boot option!
> 
> a) Sehen Sie dafür tatsächlich Bedarf?

The primary intention of the high-boot option is to provide a fall back
boot option during the development phase of new baseboards for the 
TQM5200 module, or while playing around with U-Boot on the STK52xx 
evaluation board.

We see no advantage in using the high-boot option for series production,
so the "normal" low-boot option remains the preferred way booting a
TQM5200.

> b) Wie kann der Kunde feststellen, ob der CPLD-Code auf seinem  Modul
>    Highboot unterstützt?

The high-boot option is supported on all TQM5200S modules and on the
new revisions of the TQM5200 modules with MPC5200B cpu (which will be
released soon).

> c) Wie kann der Kunde den CPLD-Code aktualisieren?

For customers it is not possible to update the CPLD code on TQM5200
modules.

> > Both U-Boot versions (low boot and high boot) are using the same
> > environment stored in flash at address 0xFC080000.
> 
> Das kann ich nicht akzeptieren. Das würde  bedeuten,  daß  der  Flash
> völlig  zerstückelt ist: Unten ein Stück frei, dann Environment, dann
> ein größeres Stück frei, dann U-Boot-Code, dann wieder frei. So  eine
> Konfiguration ist nicht sinnvoll. Wenn schon Highboot, dann legen Sie
> bitte auch das Envrionment nach oben.

Since the high-boot U-Boot is intended to be used _additionally_ to the
low-boot U-Boot (as fall back option), the flash is not fragmented by
the environment in this case.

If there is real demand for using the hight-boot option in series 
production, we will add an auxiliary configuration with both U-Boot and
environment stored at the end of flash (to avoid the pointed out flash 
fragmentation).

Attached an updated Version of the hight-boot patch. The new version
removes one configuration, to make things simpler for the users.

Viele Grüße,
Martin Krause
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