[U-Boot-Users] FW: u-boot ppc440epx bootstrap configuration without eval board

[U-Boot-Users] FW: u-boot ppc440epx bootstrap configuration without eval board

[Dave Cogley]

Forwarded to u-boot mailing list...


-----Original Message-----
From: Stefan Roese [mailto:sr at denx.de] 
Sent: Wednesday, April 02, 2008 12:01 PM
To: linuxppc-embedded at ozlabs.org
Cc: Dave Cogley
Subject: Re: u-boot ppc440epx bootstrap configuration without eval board

On Wednesday 02 April 2008, Dave Cogley wrote:
> Disregard the boot strapping problem.  It appears we are hardwired
strapped
> to use option "C" however my CPU is not being recognized as a 667MHz. 
> Which option should I be using for the 667MHz processor?

First, this is the wrong mailing list for this discussion. Please post to
the 
U-Boot list instead.

But here some general comments:

The bootstrap controller has multiple configuration options. Some of them 
result in hardwired frequencies (CPU, PLB, OPB...), and some of them load
the 
PLL setup from an I2C EEPROM. Using this bootstrap EEPROM is the most 
flexible solution. If you have only option "C", then you hardwired to
533MHz. 
There is no way to "detect" which frequency this CPU is labeled.

But it *is* possible to reconfigure the PLL from within U-Boot an reset the 
PPC to run with this different PLL setup. I just recently added some code
the 
u-boot-ppc4xx custodian repository.

Let's continue this thread on the U-Boot list.

Best regards,
Stefan

=====================================================================
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-0 Fax: +49-8142-66989-80  Email: office at denx.de
=====================================================================

[U-Boot-Users] FW: u-boot ppc440epx bootstrap configuration without eval board

[Stefan Roese]

On Wednesday 02 April 2008, Dave Cogley wrote:
> > Disregard the boot strapping problem.  It appears we are hardwired
> > strapped
> > to use option "C" however my CPU is not being recognized as a 667MHz.
> > Which option should I be using for the 667MHz processor?
>
> First, this is the wrong mailing list for this discussion. Please post to
> the
> U-Boot list instead.
>
> But here some general comments:
>
> The bootstrap controller has multiple configuration options. Some of them
> result in hardwired frequencies (CPU, PLB, OPB...), and some of them load
> the
> PLL setup from an I2C EEPROM. Using this bootstrap EEPROM is the most
> flexible solution. If you have only option "C", then you hardwired to
> 533MHz.
> There is no way to "detect" which frequency this CPU is labeled.
>
> But it *is* possible to reconfigure the PLL from within U-Boot an reset the
> PPC to run with this different PLL setup. I just recently added some code
> the
> u-boot-ppc4xx custodian repository.

Do you really have no I2C bootstrap EEPROM? If not then take a look at 
cpu/ppc4xx/cpu_init.c and search for reconfigure_pll(). This should do the 
trick.

But again, you have no chance to detect which 440EPx version is running on 
your board. So if you have boards equipped with 533MHz and 677MHz, this 
U-Boot version will run on all boards with the same speed. If you need 
different settings you really need the bootstrap EEPROM and configure board 
dependant settings.

Best regards,
Stefan

=====================================================================
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-0 Fax: +49-8142-66989-80  Email: office at denx.de
=====================================================================