Re: VAXstation 4000 TURBOchannel not working

[Felix Deichmann <m4j0rd0m0%gmail.com@localhost>]

Am 24.03.2016 um 01:10 schrieb Maciej W. Rozycki:
>   I suggest that you only map as much as an individual TC option needs, as
> reported in the REX ROM header.

You mean the "slot size" field in the ROM header [1]? This is given as a 
multiple of 4 MB. Sounds reasonable at first.

>   Most options have been designed to fit in the 4MB slot space the original
> 5000/200 TC implementation provided, and DMA options are particularly
> conservative here as all they need is the ROM space plus a bunch of
> control registers.

Accordingly, the DECstation/DECsystem 5000 Model 200 slot size is 
mentioned to be 1 (i. e. 4 MB).

But the ugly thing is that I would have to parse the ROM header for it 
in tc_vsbus.c *before* it is again parsed in the generic TC part (tc.c). 
Code duplication etc.?

What would be the preferred way to do this? Use functions from tc.c? 
Don't know how the other TC platforms do this (alpha, pmax)... Do they 
map at all or map the whole option space?

And can/should we rely on the option to report the "slot size" 
correctly? What does the "ZLX-E3 aka PMAGD-CA" actually show in "slot size"?

>   KA49 seems to be using 0x51, this is at least what my old findings
> indicate and what worked with a bunch of options I tried with the Linux
> port; I can't speak of KA46 as I didn't have one to check back when I was
> at it, but it just might be the same.

What I copied seems to work for the KA46, too.

Felix


[1] TURBOchannel Industry Group, Digital Equipment Corporation. 
TURBOchannel Firmware Specification, January 1993. EK-TCAAD-FS-004. 
ftp://ftp.hp.com/pub/alphaserver/archive/triadd/.