On Thu, 9 Dec 1999, Benjamin Herrenschmidt wrote:

> The new machines (iBook, iMacDV and G4 Sawtooth) are using a new chipset,
> but getting basic support for it should not be very complicated.
> Basically, what you need to do is:
> 
>  - Use RTAS for PCI config access & nvram
>  - Implement support for OpenPIC interrupt controller and configure it
> according to CHRP interrupt mapping
>  - Have a working via-pmu driver, don't do any ADB transaction unless
> there's an "adb" node in the device tree (iBook only)
>  - Treat IDE the same way you did for previous machines, except for the
> node named "ata-4" for which the timing register is a bit different.

Cool! Thanks!

> You can grab the linuxppc patches on my "test" web page
> (http://calvaweb.calvacom.fr/test.html) if you want to have an idea about
> what changed (those patches contains support for the 3 new machines).
> Note that I also added code to directly do PCI config accesses without
> going thru RTAS, but you should not need that since you are always
> booting via OpenFirmware.

Malhereusement, cette page n'existe pas. :-(

Also, is there any advantage to going through RTAS when you can access the
chip directly?

> Also, make sure (and this is also true for older "newworld" macs) to call
> OF "quiesce" client interface call once you are finished with OF and
> before doing anything with the MMU or moving thing in memory. This call
> will tell OF to stop bus it's drivers and will prevent any device from
> bus mastering to main memory, avoing various weird memory corruption
> problems).

Cool. That might explain one problem I ran into. On my Blue G3, I can't
"halt" (drop back into OF), only "reboot". I assume that if OF gets
returned to after a quiesce, it knows that the mappings might have been
modified?

Take care,

Bill