Re: [PATCH 3/5] PCI: rcar: Add R-Car PCIe endpoint device tree bindings

From: Geert Uytterhoeven <geert@linux-m68k.org>
To: "Lad, Prabhakar" <prabhakar.csengg@gmail.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
	Rob Herring <robh+dt@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Magnus Damm <magnus.damm@gmail.com>,
	Kishon Vijay Abraham I <kishon@ti.com>,
	Marek Vasut <marek.vasut+renesas@gmail.com>,
	Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>,
	linux-pci <linux-pci@vger.kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	Arnd Bergmann <arnd@arndb.de>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Andrew Murray <andrew.murray@arm.com>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
	<devicetree@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
	Chris Paterson <Chris.Paterson2@renesas.com>,
	"Lad, Prabhakar" <prabhakar.mahadev-lad.rj@bp.renesas.com>
Subject: Re: [PATCH 3/5] PCI: rcar: Add R-Car PCIe endpoint device tree bindings
Date: Fri, 8 Nov 2019 09:36:56 +0100	[thread overview]
Message-ID: <CAMuHMdVDdweR5Mx+RLnKCkw0kb2J=AMsAPoFm8PVbxsY2u-EvA@mail.gmail.com> (raw)
In-Reply-To: <CA+V-a8sS4gX8o__R_pHK2Otb=s_aAWbtvDLfOhAQAJb77Jz_Sw@mail.gmail.com>

Hi Prabhakar,

On Thu, Nov 7, 2019 at 11:46 PM Lad, Prabhakar
<prabhakar.csengg@gmail.com> wrote:
> On Thu, Nov 7, 2019 at 8:08 PM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> > On Thu, Nov 7, 2019 at 10:26 AM Lad, Prabhakar
> > <prabhakar.csengg@gmail.com> wrote:
> > > On Thu, Nov 7, 2019 at 8:44 AM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> > > > On Wed, Nov 6, 2019 at 8:36 PM Lad Prabhakar <prabhakar.csengg@gmail.com> wrote:
> > > > > From: "Lad, Prabhakar" <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > > > >
> > > > > This patch adds the bindings for the R-Car PCIe endpoint driver.
> > > > >
> > > > > Signed-off-by: Lad, Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > > >
> > > > > --- /dev/null
> > > > > +++ b/Documentation/devicetree/bindings/pci/rcar-pci-ep.txt

> > > > > +- reg: Five register ranges as listed in the reg-names property
> > > > > +- reg-names: Must include the following names
> > > > > +       - "apb-base"
> > > > > +       - "memory0"
> > > > > +       - "memory1"
> > > > > +       - "memory2"
> > > > > +       - "memory3"
> > > >
> > > > What is the purpose of the last 4 regions?
> > > > Can they be chosen by the driver, at runtime?
> > > >
> > > no the driver cannot choose them at runtime, as these are the only
> > > PCIE memory(0/1/2/3) ranges
> > > in the AXI address space where host memory can be mapped.
> >
> > Are they fixed by the PCIe hardware, i.e. could they be looked up by the
> > driver based on the compatible value?
> >
> yes they are fixed by the PCIe hardware and could be looked up by the driver
> based on the compatible value.

Thanks, so we don't need to describe them in DT.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds