Re: [PATCH v3 1/2] Documentation: bindings: add dt doc for Rockchip PCIe controller

From: Rob Herring <robh@kernel.org>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Wenrui Li <wenrui.li@rock-chips.com>,
	Shawn Lin <shawn.lin@rock-chips.com>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Marc Zyngier <marc.zyngier@arm.com>,
	linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-rockchip@lists.infradead.org,
	Heiko Stuebner <heiko@sntech.de>,
	Doug Anderson <dianders@chromium.org>,
	devicetree@vger.kernel.org,
	Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Subject: Re: [PATCH v3 1/2] Documentation: bindings: add dt doc for Rockchip PCIe controller
Date: Sun, 19 Jun 2016 09:53:13 -0500	[thread overview]
Message-ID: <20160619145313.GA17388@rob-hp-laptop> (raw)
In-Reply-To: <5324957.LqZqpRHMK9@wuerfel>

On Thu, Jun 16, 2016 at 11:22:02AM +0200, Arnd Bergmann wrote:
> On Thursday, June 16, 2016 4:01:12 PM CEST Wenrui Li wrote:
> > 在 2016/6/16 15:00, Arnd Bergmann 写道:
> > > On Thursday, June 16, 2016 9:50:21 AM CEST Shawn Lin wrote:
> > >
> > >> +    reset-names = "core", "mgmt", "mgmt-sticky", "pipe";
> > >> +    phys = <&pcie_phy>;
> > >> +    phy-names = "pcie-phy";
> > >> +    pinctrl-names = "default";
> > >> +    pinctrl-0 = <&pcie_clkreq>;
> > >> +    #interrupt-cells = <1>;
> > >> +    interrupt-controller;
> > >> +    interrupt-map-mask = <0 0 0 7>;
> > >> +    interrupt-map = <0 0 0 1 &pcie0 1>,
> > >> +                    <0 0 0 2 &pcie0 2>,
> > >> +                    <0 0 0 3 &pcie0 3>,
> > >> +                    <0 0 0 4 &pcie0 4>;
> > >> +};
> > >>
> > >
> > > One thing that came up in the review of the new Marvell PCIe driver is that it's
> > > most likely invalid for a device node to have both "interrupt-controller"
> > > and "interrupt-map" properties. I originally thought this was a nice way to
> > > handle embedded irqchips within the PCIe host, but it only really works
> > > by coincidence with the current kernel, and only as long as the hwirq number
> > > of the irqchip matches the integer representation of the irq line in the root
> > > bridge (which it does in the example above).
> > >
> > > For that driver we concluded that it would be less of a hack to have the
> > > irqchip as a child node of the PCIe host after all (just not with
> > > device_type="pci" of course), and that makes the translation work as
> > > expected.
> > >
> > >       Arnd
> > >
> > 
> > Original driver have an irqchip as child node. But Marc suggested don't 
> > need an intermediate node here.
> > Now the conclusion is to retain the child node?
> 
> That is at least my view of the situation, sorry for the mixed messages
> you have been getting. Marc, Rob, do you agree with my finding?

Yes, the OF interrupt mapping doc[1] parsing code treats things them as 
mutually exclusive.

Rob

[1] http://www.unixag-kl.fh-kl.de/~jkunz/tmp/imap0_9d.pdf