Re: [PATCH v3 5/5] arm64: dts: qcom: sa8775p: Add ep pcie0 controller node

Manivannan Sadhasivam
2023-10-25T07:52:40Z

On Thu, Oct 19, 2023 at 05:07:10PM +0530, Mrinmay Sarkar wrote:
> Add ep pcie dtsi node for pcie0 controller found on sa8775p platform.
> It supports gen4 and x2 link width. Due to some stability issue in
> gen4 enabling gen3 as of now.
>
> Signed-off-by: Mrinmay Sarkar <quic_msarkar@quicinc.com>
> ---
> arch/arm64/boot/dts/qcom/sa8775p.dtsi | 48 +++++++++++++++++++++++++++++++++++
> 1 file changed, 48 insertions(+)
>
> diff --git a/arch/arm64/boot/dts/qcom/sa8775p.dtsi b/arch/arm64/boot/dts/qcom/sa8775p.dtsi
> index 13dd44d..2aa7383 100644
> --- a/arch/arm64/boot/dts/qcom/sa8775p.dtsi
> +++ b/arch/arm64/boot/dts/qcom/sa8775p.dtsi
> @@ -3714,4 +3714,52 @@
>
> status = "disabled";
> };
> +
> + pcie0_ep: pcie-ep@1c00000 {
> + compatible = "qcom,sa8775p-pcie-ep";
> + reg = <0x0 0x01c00000 0x0 0x3000>,
> + <0x0 0x40000000 0x0 0xf20>,
> + <0x0 0x40000f20 0x0 0xa8>,
> + <0x0 0x40001000 0x0 0x4000>,
> + <0x0 0x40200000 0x0 0x100000>,
> + <0x0 0x01c03000 0x0 0x1000>,
> + <0x0 0x40005000 0x0 0x2000>;

Can we sort the reg entries?

> + reg-names = "parf", "dbi", "elbi", "atu", "addr_space",
> + "mmio", "dma";
> +
> + clocks = <&gcc GCC_PCIE_0_AUX_CLK>,
> + <&gcc GCC_PCIE_0_CFG_AHB_CLK>,
> + <&gcc GCC_PCIE_0_MSTR_AXI_CLK>,
> + <&gcc GCC_PCIE_0_SLV_AXI_CLK>,
> + <&gcc GCC_PCIE_0_SLV_Q2A_AXI_CLK>;
> +
> + clock-names = "aux",
> + "cfg",
> + "bus_master",
> + "bus_slave",
> + "slave_q2a";
> +
> + interrupts = <GIC_SPI 306 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 147 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 630 IRQ_TYPE_LEVEL_HIGH>;
> +
> + interrupt-names = "global", "doorbell", "dma";
> +
> + interconnects = <&pcie_anoc MASTER_PCIE_0 0 &mc_virt SLAVE_EBI1 0>,
> + <&gem_noc MASTER_APPSS_PROC 0 &config_noc SLAVE_PCIE_0 0>;
> + interconnect-names = "pcie-mem", "cpu-pcie";
> +
> + iommu-map = <0x0 &pcie_smmu 0x0000 0x1>,
> + <0x100 &pcie_smmu 0x0001 0x1>;

I think I recommended using "iommu-map" instead of "iommus" property. But
looking at it again, I think it is fine to use just "iommus" property as the SID
will be associated with the EP directly.

Unless you want to have different SID for each function.

> +
> + resets = <&gcc GCC_PCIE_0_BCR>;
> + reset-names = "core";
> + power-domains = <&gcc PCIE_0_GDSC>;
> + phys = <&pcie0_phy>;
> + phy-names = "pciephy";
> + max-link-speed = <3>;

Please add a comment here that you are limiting the Gen speed due to stability
issues. Like,

max-link-speed = <3>; /* FIXME: Limiting the Gen speed due to stability issues */

> + num-lanes = <2>;

Can you check if the controller is cache coherent? If so, we should add
"dma-coherent" property.

- Mani

> +
> + status = "disabled";
> + };
> };
> --
> 2.7.4
>

--
மணிவண்ணன் சதாசிவம்