[Fwd: Re: OpenFirmware and interrupt-map]

Tarl Neustaedter Tarl.Neustaedter at sun.com
Wed Feb 4 12:32:01 CET 2004

ron minnich wrote:
> [...] Better if we can fit it in a 1MB prom, however.
> ow. ow. ow. Not with Infiniband, at least not yet ...
> Is the price difference really that big? 

The issue is usually one of part availability and square
millimeters. On the SPARC platforms, we've usually gotten
larger proms than PCs would have, but it's been a struggle
with the hardware team every time - we (firmware) always want
more code space, the hardware team al. With the Opteron-based
systems, there is a good chance we'll be using LPC-type
parts, and nobody is bothering to manufacture large PROMs
in that technology yet.

As for infiniband drivers, I lead the team which wrote the
OpenFirmware drivers for sun, and they aren't that large.
FCode is a *very* compact programming language. To give you
an idea, the driver for the HCA is 35K, the driver for SRP
(disk over infiniband) is 16K (both values are compressed, but
with old-fashioned "compress"). The IPoIB driver was added as
an integral part of the obptftp driver, and that's 20K total.

I don't have comparable information about the Linux binaries
yet. We have Solaris drivers we wrote in-house, but they are
tied into SVR4's streams and Sun's DDI interfaces, and not
easily portable to Linux. We are likely to use an external
vendor's Linux drivers, and I'll probably know their sizes
fairly soon - giving me my first pass at feasability numbers.

[ Stefan Reinauer, on divergence of vendor's OpenFirmware ]

 > With Hypertransport, Infiniband and other technologies, there might
 > awake some demand for new supplements. Competing with EFI, Open Firmware
 > should have at least recommendations on how to cope with this divergence
 > (which is a natural fact looking at the number of contributors)

Yah. We're continuing the write these kinds of documents (e.g., I
wrote the IEEE 1275/Infiniband binding), but we no longer really
have a forum in which to share them between companies. The last
one I wrote that got published was the 1394 (Firewire) binding,
which was several years ago. There had been interest expressed by
from HP and IBM in the infiniband bindings, but it's been years
since I heard any further - and nowadays I'd probably have to
check with Sun Legal before exporting such a document. Sigh.

We haven't written an IEEE-1275/Hypertransport binding, largely
because we haven't had HT on a SPARC. The Opteron stuff is quite
recent (I recall we announced the alliance with AMD last november),
and not all the implications have finished dribbling through our
engineering organizations.

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