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From:   "Lad, Prabhakar" <prabhakar.csengg@gmail.com>
Date:   Thu, 30 Jan 2020 20:54:13 +0000
Message-ID: <CA+V-a8th3eysn0s2q9EEAqQb7vfd3bNcL=ow_z8tSWAC6K=iJw@mail.gmail.com>
Subject: Re: [v3 4/6] dt-bindings: PCI: rcar: Add bindings for R-Car PCIe
 endpoint controller
To:     Rob Herring <robh+dt@kernel.org>
Cc:     Kishon Vijay Abraham I <kishon@ti.com>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Geert Uytterhoeven <geert+renesas@glider.be>,
        Magnus Damm <magnus.damm@gmail.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>, LKML <linux-kernel@vger.kernel.org>,
        LAK <linux-arm-kernel@lists.infradead.org>,
        Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
        Chris Paterson <Chris.Paterson2@renesas.com>,
        Frank Rowand <frowand.list@gmail.com>,
        Gustavo Pimentel <gustavo.pimentel@synopsys.com>,
        Jingoo Han <jingoohan1@gmail.com>,
        Simon Horman <horms@verge.net.au>,
        Shawn Lin <shawn.lin@rock-chips.com>,
        Tom Joseph <tjoseph@cadence.com>,
        Heiko Stuebner <heiko@sntech.de>,
        "open list:ARM/Rockchip SoC..." <linux-rockchip@lists.infradead.org>,
        Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
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Hi Rob,

On Wed, Jan 22, 2020 at 8:13 AM Kishon Vijay Abraham I <kishon@ti.com> wrote:
>
> Hi Prabhakar,
>
> On 21/01/20 11:27 PM, Lad, Prabhakar wrote:
> > Hi Rob/Kishon,
> >
> > On Wed, Jan 8, 2020 at 4:22 PM Lad Prabhakar <prabhakar.csengg@gmail.com> wrote:
> >>
> >> This patch adds the bindings for the R-Car PCIe endpoint driver.
> >>
> >> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> >> ---
> >>  .../devicetree/bindings/pci/rcar-pci-ep.yaml  | 76 +++++++++++++++++++
> >>  1 file changed, 76 insertions(+)
> >>  create mode 100644 Documentation/devicetree/bindings/pci/rcar-pci-ep.yaml
> >>
> >> diff --git a/Documentation/devicetree/bindings/pci/rcar-pci-ep.yaml b/Documentation/devicetree/bindings/pci/rcar-pci-ep.yaml
> >> new file mode 100644
> >> index 000000000000..99c2a1174463
> >> --- /dev/null
> >> +++ b/Documentation/devicetree/bindings/pci/rcar-pci-ep.yaml
> >> @@ -0,0 +1,76 @@
> >> +# SPDX-License-Identifier: GPL-2.0
> >> +# Copyright (C) 2020 Renesas Electronics Europe GmbH - https://www.renesas.com/eu/en/
> >> +%YAML 1.2
> >> +---
> >> +$id: http://devicetree.org/schemas/pci/rcar-pcie-ep.yaml#
> >> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> >> +
> >> +title: Renesas R-Car PCIe Endpoint
> >> +
> >> +maintainers:
> >> +  - Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> >> +
> >> +properties:
> >> +  compatible:
> >> +    items:
> >> +      - const: renesas,r8a774c0-pcie-ep
> >> +      - const: renesas,rcar-gen3-pcie-ep
> >> +
> >> +  reg:
> >> +    maxItems: 5
> >> +
> >> +  reg-names:
> >> +    items:
> >> +      - const: apb-base
> >> +      - const: memory0
> >> +      - const: memory1
> >> +      - const: memory2
> >> +      - const: memory3
>
> As I had mentioned in the other patch, I'd prefer if we can create
> standard binding for representing the memory regions. IMHO we should
> create subnode for memory regions Each sub-node itself may or may not
> have more than one memory region.
>
> In your platform, since there can be only one allocation in a memory
> region, there should be 4 sub-nodes for each of the memory region and
> each node should have page_size (or some equivalent property) property
> to indicate page_size (= region_size).
>
> For a platform that doesn't have the restriction, there can be a single
> sub-node containing all the memory region.
>
> Let's wait for Rob's comment though.
>
Gentle ping.on the suggestions above.

Cheers,
--Prabhakar

> Thanks
> Kishon
> >> +
> >> +  power-domains:
> >> +    maxItems: 1
> >> +
> >> +  resets:
> >> +    maxItems: 1
> >> +
> >> +  clocks:
> >> +    maxItems: 1
> >> +
> >> +  clock-names:
> >> +    items:
> >> +      - const: pcie
> >> +
> >> +  max-functions:
> >> +    minimum: 1
> >> +    maximum: 6
> >> +
> >> +required:
> >> +  - compatible
> >> +  - reg
> >> +  - reg-names
> >> +  - resets
> >> +  - power-domains
> >> +  - clocks
> >> +  - clock-names
> >> +  - max-functions
> >> +
> > apart from dt_binding_check error are we OK with dt bindings ?
> >
> > Cheers,
> > --Prabhakar
> >
> >> +examples:
> >> +  - |
> >> +    #include <dt-bindings/clock/r8a774c0-cpg-mssr.h>
> >> +    #include <dt-bindings/power/r8a774c0-sysc.h>
> >> +
> >> +     pcie0_ep: pcie-ep@fe000000 {
> >> +            compatible = "renesas,r8a774c0-pcie-ep",
> >> +                         "renesas,rcar-gen3-pcie-ep";
> >> +            reg = <0 0xfe000000 0 0x80000>,
> >> +                  <0x0 0xfe100000 0 0x100000>,
> >> +                  <0x0 0xfe200000 0 0x200000>,
> >> +                  <0x0 0x30000000 0 0x8000000>,
> >> +                  <0x0 0x38000000 0 0x8000000>;
> >> +            reg-names = "apb-base", "memory0", "memory1", "memory2", "memory3";
> >> +            resets = <&cpg 319>;
> >> +            power-domains = <&sysc R8A774C0_PD_ALWAYS_ON>;
> >> +            clocks = <&cpg CPG_MOD 319>;
> >> +            clock-names = "pcie";
> >> +            max-functions = /bits/ 8 <1>;
> >> +    };
> >> --
> >> 2.20.1
> >>