Groups > linux.kernel > #1611991

RE: [PATCH v3 2/2] PCI: Add tango PCIe host bridge support

From	David Laight <David.Laight@ACULAB.COM>
Newsgroups	linux.kernel
Subject	RE: [PATCH v3 2/2] PCI: Add tango PCIe host bridge support
Date	2017-03-29 16:50 +0200
Message-ID	<tqn58-8fs-9@gated-at.bofh.it> (permalink)
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> > For my education, what is the API to send an IPI?
> > And the API to handle an IPI?
> 
> There are a few ways you could implement some custom cross-call,
> although in this case I think stop_machine() would probably be the most
> appropriate candidate. However, you're right that in general it may not
> actually help enough to be worthwhile - a DSB SY would ensure that
> in-flight transactions have at least been observed by the CPUs and any
> other coherent masters, but for any writes with a memory type allowing
> early acknowledgement (i.e. a Normal or Device mapping of a BAR) that
> doesn't necessarily correlate with them having reached their ultimate
> destination. For a PCI destination in particular, I think the normal way
> to ensure all posted writes have completed would be to read from config
> space; ah...

He almost certainly doesn't need to wait for the cycle to complete,
just long enough for the cycle to have been sent.

	David

Thread

[PATCH v3 0/2] Tango PCIe controller support Marc Gonzalez <marc_gonzalez@sigmadesigns.com> - 2017-03-29 13:40 +0200
  [PATCH v3 1/2] PCI: Add tango MSI controller support Marc Gonzalez <marc_gonzalez@sigmadesigns.com> - 2017-03-29 13:40 +0200
    Re: [PATCH v3 1/2] PCI: Add tango MSI controller support Marc Zyngier <marc.zyngier@arm.com> - 2017-03-29 14:40 +0200
      Re: [PATCH v3 1/2] PCI: Add tango MSI controller support Mason <slash.tmp@free.fr> - 2017-03-29 15:20 +0200
        Re: [PATCH v3 1/2] PCI: Add tango MSI controller support Mason <slash.tmp@free.fr> - 2017-03-29 18:00 +0200
  [PATCH v3 2/2] PCI: Add tango PCIe host bridge support Marc Gonzalez <marc_gonzalez@sigmadesigns.com> - 2017-03-29 13:40 +0200
    Re: [PATCH v3 2/2] PCI: Add tango PCIe host bridge support Robin Murphy <robin.murphy@arm.com> - 2017-03-29 14:20 +0200
      Re: [PATCH v3 2/2] PCI: Add tango PCIe host bridge support Mason <slash.tmp@free.fr> - 2017-03-29 15:00 +0200
        Re: [PATCH v3 2/2] PCI: Add tango PCIe host bridge support Robin Murphy <robin.murphy@arm.com> - 2017-03-29 16:40 +0200
          RE: [PATCH v3 2/2] PCI: Add tango PCIe host bridge support David Laight <David.Laight@ACULAB.COM> - 2017-03-29 16:50 +0200
    Re: [PATCH v3 2/2] PCI: Add tango PCIe host bridge support Rob Herring <robh@kernel.org> - 2017-04-03 17:00 +0200
  Re: [PATCH v3 0/2] Tango PCIe controller support Mason <slash.tmp@free.fr> - 2017-03-30 23:00 +0200
    Re: [PATCH v3 0/2] Tango PCIe controller support Mason <slash.tmp@free.fr> - 2017-04-01 00:10 +0200

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