From: David Laight <David.Laight@ACULAB.COM>
To: "'Robin Murphy'" <robin.murphy@arm.com>, Mason <slash.tmp@free.fr>
Cc: Marc Gonzalez <marc_gonzalez@sigmadesigns.com>,
Bjorn Helgaas <helgaas@kernel.org>,
Marc Zyngier <marc.zyngier@arm.com>,
Thomas Gleixner <tglx@linutronix.de>,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
"Liviu Dudau" <liviu.dudau@arm.com>,
linux-pci <linux-pci@vger.kernel.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
Thibaud Cornic <thibaud_cornic@sigmadesigns.com>,
Phuong Nguyen <phuong_nguyen@sigmadesigns.com>,
LKML <linux-kernel@vger.kernel.org>,
DT <devicetree@vger.kernel.org>
Subject: RE: [PATCH v3 2/2] PCI: Add tango PCIe host bridge support
Date: Wed, 29 Mar 2017 14:38:28 +0000 [thread overview]
Message-ID: <063D6719AE5E284EB5DD2968C1650D6DCFFC1507@AcuExch.aculab.com> (raw)
In-Reply-To: <84a8b26d-7d24-df29-3959-45fce880916d@arm.com>
> > 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
next prev parent reply other threads:[~2017-03-29 14:38 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-29 11:11 [PATCH v3 0/2] Tango PCIe controller support Marc Gonzalez
2017-03-29 11:29 ` [PATCH v3 1/2] PCI: Add tango MSI " Marc Gonzalez
2017-03-29 12:29 ` Marc Zyngier
2017-03-29 13:16 ` Mason
2017-03-29 15:50 ` Mason
2017-03-29 11:34 ` [PATCH v3 2/2] PCI: Add tango PCIe host bridge support Marc Gonzalez
2017-03-29 12:19 ` Robin Murphy
2017-03-29 12:53 ` Mason
2017-03-29 14:33 ` Robin Murphy
2017-03-29 14:38 ` David Laight [this message]
2017-03-30 12:09 ` kbuild test robot
2017-04-03 14:51 ` Rob Herring
2017-03-30 20:56 ` [PATCH v3 0/2] Tango PCIe controller support Mason
2017-03-31 22:05 ` Mason
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