[cgl_discussion] Hot Plug support for PICMG2.16 - Closure?

John Grana jjg at pt.com
Sun Jan 19 05:27:52 PST 2003

	In an attempt to get the PICMG 2.16 Hot Plug issue to some kind of closure,
I wanted to summarize where I think things are and (might) go forward.

	To recap. Hot Plug for PICMG 2.16 and future CompactPCI architectures
require a change to the way the present 2.5 code handles Hot Plug. Since
there is no PCI signaling on these new backplanes, the Identity portion
needs to use a different method to identify what card is in a slot. I had
proposed 4 ideas - 3 based on ethernet/TCP and 1 on IPMI. The few responses
I received felt the network method was not ideal - took too long, etc. So,
IPMI was the choice. IPMI is optional in PICMG 2.16 (but I believe a huge
majority of manufacturers implement it) and is required in CompactTCA and
AdvancedTCA. So, summary - IPMI is the method.

	Now, the next hurdle is to specify how to use IPMI. Andrew Cress proposed a
library and driver from the SAForum that can be the basis. The one issue
appears to be in licensing - see thread below. So, we can either
beg/plead/pray they whatever the issues are get resolved or just
architect/write our own. It would be a shame to duplicate the work, but what
the heck. For Hot Identity, there is not that much to do really. I am
willing to start the begging/pleading to see how to get this done.

	Summary - IPMI is the underlying method to do Hot Identity in PICMG 2.16,
CompactTCA and AdvancedTCA systems.
	We can hope the SAforum opens it's IMPI work, or implement just what we

Thanks for the responses and suggestions.

John Grana
jjg at pt.com
Performance Technologies, Inc.

-----Original Message-----
From: Cress, Andrew R [mailto:andrew.r.cress at intel.com]
Sent: Tuesday, January 14, 2003 2:44 PM
To: 'Mika Kukkonen'; Howell, David P
Cc: John Grana; greg k-h; cgl_discussion at lists.osdl.org
Subject: RE: [cgl_discussion] Re: Hot Plug support for PICMG2.16


There is a development effort under way (in SOW stage now) to implement a
library for the SAForum HPI interface on Linux IPMI platforms.  Since the
OpenIPMI driver is already going to be in the Linux 2.5+ kernel, this should
help.  The library will be in user-space.

We anticipate that the licensing issues will be resolved, such that either
the library will be open, or the non-open parts of the library will be
isolated to a shared library.  There can also be other HPI libraries for
other non-IPMI platforms.


-----Original Message-----
From: Mika Kukkonen [mailto:mika at osdl.org]
Sent: Monday, January 13, 2003 1:20 PM
To: Howell, David P
Cc: John Grana; greg k-h; cgl_discussion at lists.osdl.org
Subject: RE: [cgl_discussion] Re: Hot Plug support for PICMG2.16

On ma, 2003-01-13 at 06:38, Howell, David P wrote:
> There have been many discussions already about IPMI being closed, mostly
> coming from members providing non-IPMI hardware solutions. Seems like an
> abstraction layer that could map IPMI or other implementations would be
> in order to solve this for both.
> Wasn't there something in the SAF platform specs to address this?

As our resident SAForum insider (Peter) is out of town, I'll take a shot
on this.

Yes, SAF platform spec is specified so that other implementations than
IPMI can meet it and provide the required functionality. In other words,
I am pretty sure it is possible to make non-IPMI (c)PCI iplementation of
the SAF platform spec.

On the other hand, some people seem to think that IPMI is best since
sliced bread, so in CGL we have not seen any reason to venture outside
IPMI, although as an overall philosophy we try to stay as HW agnostic
as is reasonable (i.e. without sacrificing functionality).

Now the real question (and the main reason for this email) is that who
is going to implement the SAF platform spec on top of Linux? Assuming
IPMI there should not be much impact on the kernel, but as a first step
towards the implementation somebody should wade through the spec with
those two things (IPMI & Linux kernel) in mind and find out what needs
to be done.

Any volunteers? :-)


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