[OpenBIOS] sun4u ebus (was: Change ofmem_common.c)

Artyom Tarasenko atar4qemu at gmail.com
Fri Oct 22 18:50:31 CEST 2010

On Fri, Oct 22, 2010 at 6:38 PM, Tarl Neustädter <tarl-b2 at tarl.net> wrote:
> On 2010-10-22 5:28 AM, Artyom Tarasenko wrote:
>> On Fri, Oct 15, 2010 at 7:57 PM, Blue Swirl<blauwirbel at gmail.com>  wrote:
>>> Actually, while mc146818rtc is linked in, it's not used (there are
>>> some machines that have similar device, so that's why it still hangs
>>> around). m48t59 is on ebus.
>> Btw, can you explain how the physical address of an ebus device can be
>> calculated?
>> Looks like they are relative to the ebus beginning and then to PCI,
>> but what constants define the offsets?
> In real Sun systems, offsets onto EBus are hard-coded into the circuitry.
> E.g., a 16550 chip will be at offset x003f8. Somewhere in the upper bits (I
> think where I have the "x") will be a select value which is decoded to
> provide a select pin for the particular chip.
> In answer to your basic question, the EBus address values are provided to
> firmware by the hardware designers.

Actually I meant "in qemu", but asked on a wrong mailing list, sorry
for the noise.
(Most of the developers are present in both lists anyway).

>>> Is Netra-T1 OK?
>> Wanted to check whether the current ebus mappings match Netra-T1 or
>> U5, but haven't succeeded.
> I would generally suggest steering clear of the Netra systems - they are
> Telco modifications of more basic systems. Going with a netra may cause you
> to deal with additional stuff you don't care about.

Thanks for the hint! This can save us some time & troubles.
Just out of curiosity - do you have an example for the additional stuff`?

Artyom Tarasenko

solaris/sparc under qemu blog: http://tyom.blogspot.com/

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