From: Bjorn Helgaas <helgaas@kernel.org>
To: "Pali Rohár" <pali@kernel.org>
Cc: "Marek Behún" <marek.behun@nic.cz>,
linux-pci@vger.kernel.org, "Jason Cooper" <jason@lakedaemon.net>,
"Andrew Lunn" <andrew@lunn.ch>,
"Gregory Clement" <gregory.clement@bootlin.com>,
"Sebastian Hesselbarth" <sebastian.hesselbarth@gmail.com>,
"Thomas Petazzoni" <thomas.petazzoni@bootlin.com>,
"Lorenzo Pieralisi" <lorenzo.pieralisi@arm.com>,
"Andrew Murray" <amurray@thegoodpenguin.co.uk>,
"Remi Pommarel" <repk@triplefau.lt>,
"Tomasz Maciej Nowak" <tmn505@gmail.com>,
Xogium <contact@xogium.me>, "Rob Herring" <robh@kernel.org>
Subject: Re: [PATCH v2 4/9] PCI: aardvark: issue PERST via GPIO
Date: Thu, 23 Apr 2020 17:40:25 -0500 [thread overview]
Message-ID: <20200423224025.GA250713@google.com> (raw)
In-Reply-To: <20200423222312.5ghfmxcxnb2l5xtz@pali>
On Fri, Apr 24, 2020 at 12:23:12AM +0200, Pali Rohár wrote:
> On Thursday 23 April 2020 17:17:14 Bjorn Helgaas wrote:
> > On Thu, Apr 23, 2020 at 09:02:02PM +0200, Pali Rohár wrote:
> > > On Thursday 23 April 2020 13:41:51 Bjorn Helgaas wrote:
> > > > [+cc Rob]
> > > >
> > > > On Tue, Apr 21, 2020 at 01:16:56PM +0200, Marek Behún wrote:
> > > > > From: Pali Rohár <pali@kernel.org>
> > > > >
> > > > > Add support for issuing PERST via GPIO specified in 'reset-gpios'
> > > > > property (as described in PCI device tree bindings).
> > > > >
> > > > > Some buggy cards (e.g. Compex WLE900VX or WLE1216) are not detected
> > > > > after reboot when PERST is not issued during driver initialization.
> > > >
> > > > Does this slot support hotplug?
> > >
> > > I have no idea. I have not heard that anybody tried hotplugging cards
> > > with this aardvark pcie controller at runtime.
> > >
> > > This patch fixes initialization only at boot time when cards were
> > > plugged prior powering board on.
> > >
> > > > If so, I don't think this fix will help the hot-add case, will it?
> > >
> > > I even do not know if aardvark HW supports it. And if yes, I think it is
> > > unimplemented and/or broken.
> > >
> > > In documentation there is some interrupt register which could signal it,
> > > but I it is not used by kernel's pci-aardvark.c driver.
> >
> > "lspci -vv" will show you whether the hardware claims to support it,
> > e.g.,
> >
> > 00:1c.0 PCI bridge: Intel Corporation Sunrise Point-LP PCI Express Root Port #1
> > Capabilities: [40] Express (v2) Root Port (Slot+), MSI 00
> > SltCap: AttnBtn- PwrCtrl- MRL- AttnInd- PwrInd- HotPlug- Surprise-
> >
> > If the right combination of bits are set there, pciehp will claim the
> > port and support hotplug.
>
> aardvark controller does not have pci bridge on bus. Kernel aardvark
> driver uses pci_bridge_emul_init() for registering emulated pci bridge.
>
> Is hotplug flag from that emulated pci bridge relevant here?
I doubt it.
next prev parent reply other threads:[~2020-04-23 22:40 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-21 11:16 [PATCH v2 0/9] PCI: aardvark: Fix support for Turris MOX and Compex wifi cards Marek Behún
2020-04-21 11:16 ` [PATCH v2 1/9] PCI: aardvark: train link immediately after enabling training Marek Behún
2020-04-21 11:16 ` [PATCH v2 2/9] PCI: aardvark: don't write to read-only register Marek Behún
2020-04-23 17:27 ` Bjorn Helgaas
2020-04-23 17:51 ` Pali Rohár
2020-04-21 11:16 ` [PATCH v2 3/9] PCI: aardvark: improve link training Marek Behún
2020-04-23 18:39 ` Bjorn Helgaas
2020-04-23 18:56 ` Pali Rohár
2020-04-24 12:49 ` Pali Rohár
2020-04-21 11:16 ` [PATCH v2 4/9] PCI: aardvark: issue PERST via GPIO Marek Behún
2020-04-23 18:41 ` Bjorn Helgaas
2020-04-23 19:02 ` Pali Rohár
2020-04-23 22:17 ` Bjorn Helgaas
2020-04-23 22:23 ` Pali Rohár
2020-04-23 22:40 ` Bjorn Helgaas [this message]
2020-04-24 8:13 ` Pali Rohár
2020-04-24 9:25 ` Pali Rohár
2020-04-21 11:16 ` [PATCH v2 5/9] PCI: aardvark: add FIXME comment for PCIE_CORE_CMD_STATUS_REG access Marek Behún
2020-04-23 18:44 ` Bjorn Helgaas
2020-04-23 19:06 ` Pali Rohár
2020-04-21 11:16 ` [PATCH v2 6/9] PCI: aardvark: add PHY support Marek Behún
2020-04-21 11:16 ` [PATCH v2 7/9] dt-bindings: PCI: aardvark: describe new properties Marek Behún
2020-05-11 18:24 ` Rob Herring
2020-04-21 11:17 ` [PATCH v2 8/9] arm64: dts: marvell: armada-37xx: set pcie_reset_pin to gpio function Marek Behún
2020-04-21 11:17 ` [PATCH v2 9/9] arm64: dts: marvell: armada-37xx: move PCIe comphy handle property Marek Behún
2020-04-21 11:42 ` [PATCH v2 0/9] PCI: aardvark: Fix support for Turris MOX and Compex wifi cards Pali Rohár
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