RE: [PATCH v17 16/20] dt-bindings: PCI: renesas: Add R-Car Gen4 PCIe Endpoint

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Hello Serge,

> From: Serge Semin, Sent: Wednesday, July 12, 2023 6:03 AM
> 
> On Wed, Jul 05, 2023 at 08:42:02PM +0900, Yoshihiro Shimoda wrote:
> > Document bindings for Renesas R-Car Gen4 and R-Car S4-8 (R8A779F0)
> > PCIe endpoint module.
> >
> > Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
> > Reviewed-by: Rob Herring <robh@xxxxxxxxxx>
> > Reviewed-by: Serge Semin <fancer.lancer@xxxxxxxxx>
> > Acked-by: Manivannan Sadhasivam <mani@xxxxxxxxxx>
> > ---
> >  .../bindings/pci/rcar-gen4-pci-ep.yaml        | 106 ++++++++++++++++++
> >  1 file changed, 106 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/pci/rcar-gen4-pci-ep.yaml
> >
> > diff --git a/Documentation/devicetree/bindings/pci/rcar-gen4-pci-ep.yaml
> b/Documentation/devicetree/bindings/pci/rcar-gen4-pci-ep.yaml
> > new file mode 100644
> > index 000000000000..4e6be856104c
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/pci/rcar-gen4-pci-ep.yaml
> > @@ -0,0 +1,106 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +# Copyright (C) 2022-2023 Renesas Electronics Corp.
> > +%YAML 1.2
> > +---
> > +$id:
<snip URL>
> > +$schema:
<snip URL>
> > +
> > +title: Renesas R-Car Gen4 PCIe Endpoint
> > +
> > +maintainers:
> > +  - Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
> > +
> > +allOf:
> > +  - $ref: snps,dw-pcie-ep.yaml#
> > +
> > +properties:
> > +  compatible:
> > +    items:
> > +      - const: renesas,r8a779f0-pcie-ep   # R-Car S4-8
> > +      - const: renesas,rcar-gen4-pcie-ep  # R-Car Gen4
> > +
> > +  reg:
> > +    maxItems: 6
> > +
> > +  reg-names:
> > +    items:
> > +      - const: dbi
> > +      - const: dbi2
> > +      - const: atu
> > +      - const: dma
> > +      - const: app
> > +      - const: addr_space
> > +
> > +  interrupts:
> > +    maxItems: 3
> > +
> > +  interrupt-names:
> > +    items:
> > +      - const: dma
> > +      - const: sft_ce
> > +      - const: app
> > +
> > +  power-domains:
> > +    maxItems: 1
> > +
> > +  resets:
> > +    maxItems: 1
> > +
> > +  clocks:
> > +    maxItems: 2
> > +
> > +  clock-names:
> > +    items:
> > +      - const: core
> > +      - const: ref
> > +
> > +  max-functions:
> > +    maximum: 2
> > +
> > +  max-link-speed:
> > +    maximum: 4
> > +
> > +  num-lanes:
> > +    maximum: 4
> > +
> > +required:
> > +  - compatible
> > +  - reg
> > +  - reg-names
> > +  - interrupts
> > +  - resets
> > +  - power-domains
> > +  - clocks
> > +  - clock-names
> > +
> > +unevaluatedProperties: false
> > +
> > +examples:
> > +  - |
> > +    #include <dt-bindings/clock/r8a779f0-cpg-mssr.h>
> > +    #include <dt-bindings/interrupt-controller/arm-gic.h>
> > +    #include <dt-bindings/power/r8a779f0-sysc.h>
> > +
> > +    soc {
> > +        #address-cells = <2>;
> > +        #size-cells = <2>;
> > +
> > +        pcie0_ep: pcie-ep@e65d0000 {
> > +            compatible = "renesas,r8a779f0-pcie-ep", "renesas,rcar-gen4-pcie-ep";
> 
> > +            reg = <0 0xe65d0000 0 0x2000>, <0 0xe65d2800 0 0x0800>,
> > +                  <0 0xe65d3000 0 0x2000>, <0 0xe65d5000 0 0x1200>,
> > +                  <0 0xe65d6200 0 0x0e00>, <0 0xfe000000 0 0x400000>;
> > +            reg-names = "dbi", "dbi2", "atu", "dma", "app", "addr_space";
> 
> I'll ask it once again since you didn't address my comment in v16 and
> haven't fixed the example node in the bindings:

Thank you for your review! I'm sorry, I completely forgot about this...

> I see you defining the dbi2 space as <0 _0xe65d2800_ 0 0x0800>. But
> sometime before you mentioned that your device has the next CSRs
> layout:
> ! +0x0000 : Function 0 (common address in Root port and Endpoint mode)
>   +0x1000 : Function 1 (Endpoint mode only)
>   +0x2000 : Shadow register for Function 0
> ! +0x2800 : Shadow register for Function 1
> it means the DT-bindings example node has the dbi space defined for
> both functions meanwhile the dbi2 space defined for _function #1_ only
> (it's 0xe65d0000 + 0x2800). So AFAICS either you have wrong space
> defined in the example node or the node is wrong in your platform DTS
> too and you have a malfunction end-point mode. Am I missing something?
> In any case based on your End-point driver implementation dbi2 is
> supposed to be defined at the 0xe65d2000 base address.
> 
> Am I wrong? Could you clarify this?

You're correct. So, I had investigated this topic, and then the current
actual dtsi file has the following about the reg property:

+                       reg = <0 0xe65d0000 0 0x2000>, <0 0xe65d2000 0 0x1000>,
+                             <0 0xe65d3000 0 0x2000>, <0 0xe65d5000 0 0x1200>,
+                             <0 0xe65d6200 0 0x0e00>, <0 0xfe000000 0 0x400000>;

After that, the driver could not work correctly on v16 patch series.
So, I had investigated why, and then I found this was related to
the dbi2 offset. That's why I added a new patch [1] on v17 patch series.

[1] "[PATCH v17 07/20] PCI: dwc: endpoint: Add multiple PFs support for dbi2"

Anyway, I'll revise this dt-bindings doc too on v18 patch series.

Best regards,
Yoshihiro Shimoda

> -Serge(y)
> 
> > +            interrupts = <GIC_SPI 417 IRQ_TYPE_LEVEL_HIGH>,
> > +                         <GIC_SPI 418 IRQ_TYPE_LEVEL_HIGH>,
> > +                         <GIC_SPI 422 IRQ_TYPE_LEVEL_HIGH>;
> > +            interrupt-names = "dma", "sft_ce", "app";
> > +            clocks = <&cpg CPG_MOD 624>, <&pcie0_clkref>;
> > +            clock-names = "core", "ref";
> > +            power-domains = <&sysc R8A779F0_PD_ALWAYS_ON>;
> > +            resets = <&cpg 624>;
> > +            num-lanes = <2>;
> > +            max-link-speed = <4>;
> > +            max-functions = /bits/ 8 <2>;
> > +        };
> > +    };
> > --
> > 2.25.1
> >




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