[U-Boot-Users] [PATCH v2] PPC440EPx: Reconfigure PLL for 667MHz processor

[Matthias Fuchs]

Hi Mike,

don't you think this is a little bit to shortsighted?
There are many other parameters beyond the CPU clock that could be
modified in such a way. We have some code in the PMC440 board
code that sets up the PCI sync clock dynamically dependant on 
a GPIO (M66EN pci pin). So I would vote for a more generic configuration than 
by a CPU frequency parameter. Just think about this: should 667 MHz on an EPx
always mean 166 MHz PLB clock? 667MHZ with 133MHz PLB might also be 
a typical configuration (e.g. when you need 66MHz EBC clock ....).

So what about a function that takes the complete strapping values 
as parameters (I think 4 longs) instead of nothing but the CPU frequency.

Matthias

On Wednesday 20 February 2008 17:54:20 Mike Nuss wrote:
> On PPC440EPx without a bootstrap I2C EEPROM, the PLL can be reconfigured
> after startup to change the speed of the clocks. This patch adds the
> option CFG_PLL_RECONFIG. If this option is set to 667, the CPU
> initialization code will reconfigure the PLL to run the system with a CPU
> frequency of 667MHz and PLB frequency of 166MHz, without the need for an
> external EEPROM.
>
> Signed-off-by: Mike Nuss <mike at terascala.com>
> Cc: Stefan Roese <sr at denx.de>