Hello, Bjorn, what do you think of my input?

Regards,

Chen

On 2025/2/12 13:54, Chen Wang wrote:

On 2025/2/12 12:25, Bjorn Helgaas wrote:
[......]

quoted

quoted

pcie_rc1 and pcie_rc2 share registers in cdns_pcie1_ctrl. By using
different "sophgo,core-id" values, they can distinguish and access
the registers they need in cdns_pcie1_ctrl.

Where does cdns_pcie1_ctrl fit in this example?  Does that enclose
both pcie_rc1 and pcie_rc2?

cdns_pcie1_ctrl is defined as a syscon node,  which contains registers 
shared by pcie_rc1 and pcie_rc2. In the binding yaml file, I drew a 
diagram to describe the relationship between them, copy here for your 
quick reference:

+                     +-- Core (Link0) <---> pcie_rc1 +-----------------+
+                     | |                 |
+      Cadence IP 2 --+                                | 
cdns_pcie1_ctrl |
+                     | |                 |
+                     +-- Core (Link1) <---> pcie_rc2 +-----------------+

The following is an example with cdns_pcie1_ctrl added. For 
simplicity, I deleted pcie_rc0.

pcie_rc1: pcie@7062000000 {
    compatible = "sophgo,sg2042-pcie-host";
    ...... // host bride level properties
    linux,pci-domain = <1>;
    sophgo,core-id = <0>;
    sophgo,syscon-pcie-ctrl = <&cdns_pcie1_ctrl>;
    port {
        // port level properties
        vendor-id = <0x1f1c>;
        device-id = <0x2042>;
        num-lanes = <2>;
    };
};

pcie_rc2: pcie@7062800000 {
    compatible = "sophgo,sg2042-pcie-host";
    ...... // host bride level properties
    linux,pci-domain = <2>;
    sophgo,core-id = <1>;
    sophgo,syscon-pcie-ctrl = <&cdns_pcie1_ctrl>;
    port {
        // port level properties
        vendor-id = <0x1f1c>;
        device-id = <0x2042>;
        num-lanes = <2>;
    }

};

cdns_pcie1_ctrl: syscon@7063800000 {
    compatible = "sophgo,sg2042-pcie-ctrl", "syscon";
    reg = <0x70 0x63800000 0x0 0x800000>;
};


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