On Sun, 17 Nov 2024 at 13:51, Krishna Kurapati quic_kriskura@quicinc.com wrote:

On 11/15/2024 9:29 PM, Dmitry Baryshkov wrote:

...

On Fri, Nov 15, 2024 at 02:45:45PM +0530, Krishna Kurapati wrote:

...

Commit [1] introduced DP support to QMP driver. While doing so, the dp and usb configuration structures were added to a combo_phy_cfg structure. During probe, the match data is used to parse and identify the dp and usb configs separately. While doing so, the usb_cfg variable represents the configuration parameters for USB part of the phy (whether it is DP-Cobo or Uni). during probe, one corner case of parsing usb_cfg for Uni PHYs is left incomplete and it is left as NULL. This NULL variable further percolates down to qmp_phy_create() call essentially getting de-referenced and causing a crash.

The UNI PHY platforms don't have usb3-phy subnode. As such the usb_cfg variable should not be used in the for_each_available_child_of_node() loop.

Please provide details for the platform on which you observe the crash and the backtrace.

I got this error when I started working on multiport support (begining of 2023). Initially I tried testing on my code on 5.15, hence this patch was raised on the same.

The 2 qmp phys on sa8195 and sa8295 (based on sc8280xp) are uni phy and the following was the DT node that worked out for me on 5.15 codebase:

    usb_1_qmpphy: ssphy@88eb000 {
            compatible = "qcom,sm8150-qmp-usb3-uni-phy";
            reg = <0x088eb000 0x200>;
            #address-cells = <1>;
            #size-cells = <1>;
            ranges;
            //status = "disabled";
            clocks = <&gcc GCC_USB3_MP_PHY_AUX_CLK>,
                     <&rpmhcc RPMH_CXO_CLK>,
                     <&gcc GCC_USB3_SEC_CLKREF_CLK>,
                     <&gcc GCC_USB3_MP_PHY_COM_AUX_CLK>;
            clock-names = "aux", "ref_clk_src", "ref", "com_aux";

            resets = <&gcc GCC_USB3UNIPHY_PHY_MP0_BCR>,
                     <&gcc GCC_USB3_UNIPHY_MP0_BCR>;
            reset-names = "phy", "common";

            //vdda-phy-supply = <&L3C>;
            vdda-pll-supply = <&L5E>;

            usb_1_ssphy: usb3-phy@88eb200 {

As this is a UNI PHY and not a combo PHY, the child node should be just phy@, not usb3-phy@. See Documentation/devicetree/bindings/phy/qcom,qmp-phy.yaml

                    reg = <0x088eb200 0x200>,
                          <0x088eb400 0x200>,
                          <0x088eb800 0x800>,
                          <0x088eb600 0x200>;
                    #clock-cells = <0>;
                    #phy-cells = <0>;
                    clocks = <&gcc GCC_USB3_MP_PHY_PIPE_0_CLK>;
                    clock-names = "pipe0";
                    clock-output-names = "usb3_uni_phy_pipe_clk_src";
            };
    };

I was hitting the bug when I write the DT above way on top of 5.15 baseline.

In 5.15.y, the SM8150 usb_2_qmpphy dT is as follows:

             usb_2_qmpphy: phy@88eb000 {
                     compatible = "qcom,sm8150-qmp-usb3-uni-phy";
                     reg = <0 0x088eb000 0 0x200>;
                     status = "disabled";
                     #address-cells = <2>;
                     #size-cells = <2>;
                     ranges;

                     clocks = <&gcc GCC_USB3_SEC_PHY_AUX_CLK>,
                              <&rpmhcc RPMH_CXO_CLK>,
                              <&gcc GCC_USB3_SEC_CLKREF_CLK>,
                              <&gcc GCC_USB3_SEC_PHY_COM_AUX_CLK>;
                     clock-names = "aux", "ref_clk_src", "ref",

"com_aux";

                     resets = <&gcc GCC_USB3PHY_PHY_SEC_BCR>,
                              <&gcc GCC_USB3_PHY_SEC_BCR>;
                     reset-names = "phy", "common";

                     usb_2_ssphy: phy@88eb200 {

Just as I wrote, this one correctly uses phy@

                             reg = <0 0x088eb200 0 0x200>,
                                   <0 0x088eb400 0 0x200>,
                                   <0 0x088eb800 0 0x800>,
                                   <0 0x088eb600 0 0x200>;
                             #clock-cells = <0>;
                             #phy-cells = <0>;
                             clocks = <&gcc GCC_USB3_SEC_PHY_PIPE_CLK>;
                             clock-names = "pipe0";
                             clock-output-names =

"usb3_uni_phy_pipe_clk_src"; }; };

IIRC, when I tried using the above sm8150 dt on 5.15.y, the phy_create was (either not getting called) or crashing. Probably because "of_node_name_eq()" didn't find either "dp-phy" or "usb3-phy" and cfg variable was NULL.

Unless somebody backported some patch in an incorrect way, the SM8150 DT entry is correct, while SA8xxx is not,

I can try reproducing the issue and get back again in a week.

Yes, please.

Apologies if I have misunderstood something and this patch doesn't make sense. Let me know if I have made any mistake anywhere (either in my DT) or in understanding.

Regards, Krishna,