Subject: Re: [PATCH] Start arch/powerpc/boot code reorganization

From: Sergei Shtylyov <[email-masked]>
Date: Fri, 29 Sep 2006 00:53:21 +0400

Hello.

Segher Boessenkool wrote:

>>>Yes.  Except a "cell" is not what you think it is.  A "cell" is the
>>>size of numbers OF deals with internally; just deal with it.  Of
>>>course, there's things like "#address-cells", which really mean
>>>"#-32bit-things-per-address".

>>Okay, well, when I talked about cells I meant "#-32bit-things-per- 
>>address".
>>Obviously it was silly of me to think that "#address-cells" meant  
>>the # of
>>address cells...

> Some background might clear things up (or not)...  A "cell" is the
> unit of data in a Forth system.  When OF was young (and not yet
> called OF), all systems were 32-bit, and the 32-bit-thingies in
> the properties (which weren't yet called properties) in the device
> tree were called cells as well.  When 64-bit came into the picture,
> everything fell apart.  The "correct" name for the property thingies
> now is "integers as encoded with encode-int".

    I looked into the OF 64-bit extensions spec, and "cell" is 64-bit there.
So, "address" should look valid. I don't know whether PPC64 boxes support 
64-bit OF, or only 32-bit, however, the kernel doesn't seem to deal with 
64-bit ones correctly, so I'm assuming that 32-bit OF is at least available...
    Anyway, I'm still missing the point of not using "address" which is 
clearly intended for such case.

WBR, Sergei