MPC8240 EPIC Driver (Attached)

James F Dougherty jfd at GigabitNetworks.COM
Tue Aug 14 17:43:16 EST 2001


Send me your changes and I'll
gladly test them...


> > "Mark A. Greer" wrote:
> > >
> > > The changes to the openpic code for supporting serial interrupt mode are
very minor.
> >
> > Actually IIRC they're already present in the version shipped with
> > HHL-2.0.  I don't remember making any changes for that at all on the
> > MVME2100 support, but my memory has been known to be faulty.
> Well, there is no _explicit_ support for serial mode but there was an 'if'
stmt added that
> adjusts NumSources if it is less than OpenPIC_NumInitSenses.  That let's you
proceed with
> an initsenses with more irq's than the pic tells you it has.  Its not a
complete, long-term
> solution.
> Also, I'm trying to keep this discussion relative to 2_4_devel not hhlx.x
> > > What I mean is a table where you specify the irq, the offset fo the regs
from the base
> > > address, the sensitivity, and the polarity all separately.  Also the
> > > extensions to support serial interrupt mode (e.g., MVME2100 uses that).
With a table
> > > format something like that, you can avoid the sparse and negative irq's on
> > > 8240/107 and still keep things pretty clean looking.
> >
> > That sounds right.  It could also use the NIRQ field of the Feature
> > Reporting Register to cross-check that the table given is the correct size
> > for the chip it's controlling, and have some way of specifying the
> > presence or absensce of a cascaded i8259 (presumably with its own table).
> The NIRQ field is a part of the problem in serial mode.  You can have 16 lines
hooked up in
> serial mode and the NIRQ still tells you that there should only be 5, IIRC.
> The table changes are intended to solve more than just epic serial mode.
They're intended
> to make explicit--and flexible--all the assumptions that are currently buried
in the
> initsenses table (irq #, the offset of corresponding reg in pic, sensifivity
> polarity).  These aren't extensive changes, I should just do them, post a
patch for review
> & shut up...  :)
> Mark

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