Re: [PATCH RFC 0/7] Adding core support for wire-MSI bridges

From	Thomas Gleixner <tglx@linutronix.de>
Newsgroups	linux.kernel
Subject	Re: [PATCH RFC 0/7] Adding core support for wire-MSI bridges
Date	2015-11-05 13:30 +0100
Message-ID	<qrrPX-6Ed-5@gated-at.bofh.it> (permalink)
References	<qjSNk-2aP-7@gated-at.bofh.it> <qk2tj-8h1-3@gated-at.bofh.it> <qk8S6-12c-1@gated-at.bofh.it> <qr6sa-133-9@gated-at.bofh.it> <qrrPX-6Ed-7@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

On Thu, 5 Nov 2015, Marc Zyngier wrote:
> On 04/11/15 13:34, Thomas Gleixner wrote:
> > Marc,
> > 
> > On Fri, 16 Oct 2015, Marc Zyngier wrote:
> >> On 16/10/15 02:55, Jiang Liu wrote:
> >>> 	There's a working to enable Intel VMD storage device, which
> >>> has the similar requirement. Basically a PCIe hierarchy is hidden
> >>> behind a parent PCIe device, so we need to use the PCIe irqs on parent
> >>> to de-multiple PCIe IRQs from hidden PCIe devices. Seems a chance for
> >>> consolidation here.
> >>
> >> Do you know if there is a 1-1 mapping between the interrupts seen by the
> >> parent device and those seen by the hidden devices? Or is it a case of
> >> having to demultiplex the MSIs? Looks like the former, but I'd like to
> >> be sure.
> > 
> > Yes, it's a demultiplexer. No 1:1 mapping.
> 
> Right. This doesn't exactly fit the scheme I have so far (there is a 1:1
> mapping between the wired interrupt and the MSI), but once we are able
> to expose an MSI domain, it could be possible to construct the MSI
> demultiplexer on top. That's a lot of layers! ;-)

Well for the demux case it doesn't make a lot of sense. It's not easy
to describe in a hierarchy. Having that parentless MSI domain for that
VMD case is simple enough.

Thanks,

	tglx
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Thread

Re: [PATCH RFC 0/7] Adding core support for wire-MSI bridges Thomas Gleixner <tglx@linutronix.de> - 2015-11-04 14:40 +0100
  Re: [PATCH RFC 0/7] Adding core support for wire-MSI bridges Thomas Gleixner <tglx@linutronix.de> - 2015-11-05 13:30 +0100
  Re: [PATCH RFC 0/7] Adding core support for wire-MSI bridges Marc Zyngier <marc.zyngier@arm.com> - 2015-11-05 13:30 +0100

csiph-web