From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: "Chocron, Jonathan" <jonnyc@amazon.com>,
"helgaas@kernel.org" <helgaas@kernel.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"robh+dt@kernel.org" <robh+dt@kernel.org>,
"jingoohan1@gmail.com" <jingoohan1@gmail.com>,
"Woodhouse, David" <dwmw@amazon.co.uk>,
"Hanoch, Uri" <hanochu@amazon.com>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
"lorenzo.pieralisi@arm.com" <lorenzo.pieralisi@arm.com>,
"gustavo.pimentel@synopsys.com" <gustavo.pimentel@synopsys.com>,
"Wasserstrom, Barak" <barakw@amazon.com>,
"Saidi, Ali" <alisaidi@amazon.com>,
"mark.rutland@arm.com" <mark.rutland@arm.com>,
"Hawa, Hanna" <hhhawa@amazon.com>,
"Shenhar, Talel" <talel@amazon.com>,
"Krupnik, Ronen" <ronenk@amazon.com>,
"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>
Subject: Re: [PATCH 4/8] PCI: Add quirk to disable MSI support for Amazon's Annapurna Labs host bridge
Date: Mon, 15 Jul 2019 08:54:00 +1000 [thread overview]
Message-ID: <54a3e2de1baf2aab893ab6370f8f6ec0a83c45db.camel@kernel.crashing.org> (raw)
In-Reply-To: <2cac43401f0cf76acb645b98c6543204f12d5c05.camel@amazon.com>
On Sun, 2019-07-14 at 15:09 +0000, Chocron, Jonathan wrote:
> > s/host bridge/Root Port/, if I understand correctly.
> >
>
> Ack.
>
> BTW, what is the main difference between the 2 terms, since they seem
> to be (mistakenly?) used interchangeably?
The host bridge is the parent of the root port. You can have several
root ports under a host bridge in fact. They tend to be part of the
same silicon and somewhat intimately linked but they are distinct
logical entities. The root port appears as a PCIe p2p bridge sitting on
the top level bus provided by the host bridge. The Host Bridge doesn't
have to have a representation in config space (it sometimes does
historically, but as a sibling of the devices on that top level bus. In
PCIe land, these are chipset built-in devices).
Ben.
next prev parent reply other threads:[~2019-07-14 22:54 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-11 14:50 [PATCH 0/8] Amazon's Annapurna Labs DT-based PCIe host controller driver Jonathan Chocron
2019-07-11 14:45 ` [PATCH 5/8] dt-bindings: PCI: Add Amazon's Annapurna Labs PCIe host bridge binding Jonathan Chocron
2019-07-11 7:12 ` Shenhar, Talel
2019-07-11 9:32 ` Lorenzo Pieralisi
2019-07-11 15:44 ` Chocron, Jonathan
2019-07-11 14:53 ` [PATCH 1/8] PCI: Add Amazon's Annapurna Labs vendor ID Jonathan Chocron
2019-07-12 13:04 ` Bjorn Helgaas
2019-07-11 14:55 ` [PATCH 2/8] PCI: Add ACS quirk for Amazon Annapurna Labs root ports Jonathan Chocron
2019-07-11 14:55 ` [PATCH 3/8] PCI/VPD: Add VPD release quirk for Amazon Annapurna Labs host bridge Jonathan Chocron
2019-07-12 13:10 ` Bjorn Helgaas
2019-07-14 15:08 ` Chocron, Jonathan
2019-07-11 14:56 ` [PATCH 4/8] PCI: Add quirk to disable MSI support for Amazon's " Jonathan Chocron
2019-07-12 13:04 ` Bjorn Helgaas
2019-07-14 15:09 ` Chocron, Jonathan
2019-07-14 22:54 ` Benjamin Herrenschmidt [this message]
2019-07-11 14:57 ` [PATCH 6/8] PCI: al: Add support for DW based driver type Jonathan Chocron
2019-07-12 13:42 ` Bjorn Helgaas
2019-07-15 15:18 ` Chocron, Jonathan
2019-07-11 14:57 ` [PATCH 7/8] PCI: dw: Add validation that PCIe core is set to correct mode Jonathan Chocron
2019-07-11 14:57 ` [PATCH 8/8] PCI: dw: Add support for PCI_PROBE_ONLY/PCI_REASSIGN_ALL_BUS flags Jonathan Chocron
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