Re: How to recognize a LEON CPU?

[Daniel Hellstrom <daniel@gaisler.com>]

On 05/21/2012 06:22 PM, Sam Ravnborg wrote:
> Who is the relevant Gaisler contact person these days for Linux stuff?
> I sometimes uses Daniel, sometimes Konrad.
Please CC both of us. Kristoffer Glembo is no longer active though.

> I can just add both of you - this is no problem.
> As I plan to update the LEON integration it would be good
> to have in place.
>
> Anyway - the real question..
>
> In head_32.S I need very early on to determine the CPU type,
> so I can distingush between LEON and SUN.
> This is due to LEON using a different ASI for mmuregs
> as discussed in another mail.
>
> I assume this can be determinded from PSR.
> If this is correct - then what values shall I use
> to determine if the relevant cpu is LEON or SUN?
The LEON is SPARC compliant and has a registered number, from the manual (http://gaisler.com/products/grlib/grip.pdf section LEON3 and LEON4):

65.2.3 SPARC Implementor's ID
Gaisler Research is assigned number 15 (0xF) as SPARC implementor's identification. This value is
hard-coded into bits 31:28 in the %psr register. The version number for LEON3 is 3, which is hard-
coded in to bits 27:24 of the %psr.


Note that LEON3 and LEON4 have the same version number, they are software compatible.

Daniel