On 2010-10-22 5:28 AM, Artyom Tarasenko wrote:
On Fri, Oct 15, 2010 at 7:57 PM, Blue Swirlblauwirbel@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.
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.