Multiple dec2114x units on ppc

[Joel Sherrill]

gregory.menke at gsfc.nasa.gov wrote:
> 
> Till Straumann writes:
>  > gregory.menke at gsfc.nasa.gov wrote:
>  > > Till Straumann writes:
>  > >  > Gregory.

Sorry .. deleted some comment about irq API on/off.  I believe
these are support routines that should be able to be provided 
by the BSP for a specific DEC NIC interface.  Just because it is
a particular NIC doesn't mean it has the usual interrupt setup.
The "normal" way could be provided as support routines which the
BSP could configure without providing them itself.

This is simply part of the glue that a BSP may have to provide or
use defaults.

>  > NOTE: since the BSP doesn't implement true IRQ sharing,
>  >        you run into trouble as soon as different PCI
>  >        devices (i.e. a dec2114x and some other device)
>  >        share a common IRQ line.
> 
> It looks like managing the cpci vectoring in some kind of organized
> way will be quite a pain.  It makes me almost want to defer it to the
> user- if they want cpci devices, they must supply INTERRUPT_PIN and
> INTERRUPT_LINE(for translation to interrupt name) for each device
> they're going to use.  Its not pretty, but it would keep things
> simpler.

I don't know the exact interrupt structure the baord has but 
we found that a PowerPC BSP almost has to support being able to
have an "ISR handler" that is in fact a second level vectoring
routine.  THe case I am thinking of is a PMC module that has about
15 interrupt sources on it.  It is mapped to a single IRQ to the
baseboard which is in turn off of an IRQ.  You get one interrupt
that says "something on the PMC wants attention" and it is up to 
"PMC specific vectoring routine" to figure out which one.  

I don't know how if anything I said applies.


--joel