Re: [PATCH v2 3/3] riscv: dts: thead: Add TH1520 ethernet nodes

[Drew Fustini <dfustini@tenstorrent.com>]

On Fri, Sep 27, 2024 at 01:58:40PM +0200, Andrew Lunn wrote:
> > I tried to setup an nfs server with a rootfs on my local network. I can
> > mount it okay from my laptop so I think it is working okay. However, it
> > does not seem to work on the lpi4a [3]. It appears the rgmii-id
> > validation fails and the dwmac driver can not open the phy:
> > 
> >  thead-dwmac ffe7060000.ethernet eth0: Register MEM_TYPE_PAGE_POOL RxQ-0
> >  thead-dwmac ffe7060000.ethernet eth0: validation of rgmii-id with support \
> >              00,00000000,00000000,00006280 and advertisementa \
> > 	     00,00000000,00000000,00006280 failed: -EINVAL
> >  thead-dwmac ffe7060000.ethernet eth0: __stmmac_open: Cannot attach to PHY (error: -22)
> 
> Given what Emil said, i would suggest flipping the MDIO busses
> around. Put the PHYs on gmac1's MDIO bus, and set the pinmux so that
> its MDIO bus controller is connected to the outside world. Then, when
> gmac1 probes first, its MDIO bus will be probed at the same time, and
> its PHY found.
> 
> 	Andrew

I'm trying to configure the pinmux to have gmac1 control the mdio bus
but it seems I've not done so correctly. I changed pins "GMAC0_MDC" and
"GMAC0_MDIO" to function "gmac1" (see the patch below).

I don't see any errors about the dwmac or phy in the boot log [1] but
ultimately there is no carrier detected and the ethernet interface does
not come up.

Section "3.3.4.103 G3_MUXCFG_007" in the TH1520 System User Manual shows
that bits [19:16] control GMAC0_MDIO_MUX_CFG where value of 2 selects
GMAC1_MDIO. Similarly, bits [15:12] control GMAC0_MDC_MUX_CFG where a
value of 2 also selects GMAC1_MDC.

Emil - do you have any suggestion as to what I might be doing wrong with
the pinmux?

Thanks,
Drew

[1] https://gist.github.com/pdp7/1f9fcd76f26acd5715398d54f65a2e27

diff --git a/arch/riscv/boot/dts/thead/th1520-lichee-module-4a.dtsi b/arch/riscv/boot/dts/thead/th1520-lichee-module-4a.dtsi
index ca84bc2039ef..f2f6c9d9b590 100644
--- a/arch/riscv/boot/dts/thead/th1520-lichee-module-4a.dtsi
+++ b/arch/riscv/boot/dts/thead/th1520-lichee-module-4a.dtsi
@@ -11,6 +11,11 @@ / {
        model = "Sipeed Lichee Module 4A";
        compatible = "sipeed,lichee-module-4a", "thead,th1520";

+       aliases {
+               ethernet0 = &gmac0;
+               ethernet1 = &gmac1;
+       };
+
        memory@0 {
                device_type = "memory";
                reg = <0x0 0x00000000 0x2 0x00000000>;
@@ -55,6 +60,22 @@ &sdio0 {
        status = "okay";
 };

+&gmac0 {
+       pinctrl-names = "default";
+       pinctrl-0 = <&gmac0_pins>;
+       phy-handle = <&phy0>;
+       phy-mode = "rgmii-id";
+       status = "okay";
+};
+
+&gmac1 {
+       pinctrl-names = "default";
+       pinctrl-0 = <&gmac1_pins>, <&mdio1_pins>;
+       phy-handle = <&phy1>;
+       phy-mode = "rgmii-id";
+       status = "okay";
+};
+
 &gpio0 {
        gpio-line-names = "", "", "", "", "", "", "", "", "", "",
                          "", "", "", "", "", "", "", "", "", "",
@@ -87,3 +108,101 @@ &gpio3 {
                          "GPIO09",
                          "GPIO10";
 };
+
+&mdio1 {
+       phy0: ethernet-phy@1 {
+               reg = <1>;
+       };
+
+       phy1: ethernet-phy@2 {
+               reg = <2>;
+       };
+};
+
+&padctrl0_apsys {
+       gmac0_pins: gmac0-0 {
+               tx-pins {
+                       pins = "GMAC0_TX_CLK",
+                              "GMAC0_TXEN",
+                              "GMAC0_TXD0",
+                              "GMAC0_TXD1",
+                              "GMAC0_TXD2",
+                              "GMAC0_TXD3";
+                       function = "gmac0";
+                       bias-disable;
+                       drive-strength = <25>;
+                       input-disable;
+                       input-schmitt-disable;
+                       slew-rate = <0>;
+               };
+
+               rx-pins {
+                       pins = "GMAC0_RX_CLK",
+                              "GMAC0_RXDV",
+                              "GMAC0_RXD0",
+                              "GMAC0_RXD1",
+                              "GMAC0_RXD2",
+                              "GMAC0_RXD3";
+                       function = "gmac0";
+                       bias-disable;
+                       drive-strength = <1>;
+                       input-enable;
+                       input-schmitt-disable;
+                       slew-rate = <0>;
+               };
+       };
+
+       gmac1_pins: gmac1-0 {
+               tx-pins {
+                       pins = "GPIO2_18", /* GMAC1_TX_CLK */
+                              "GPIO2_20", /* GMAC1_TXEN */
+                              "GPIO2_21", /* GMAC1_TXD0 */
+                              "GPIO2_22", /* GMAC1_TXD1 */
+                              "GPIO2_23", /* GMAC1_TXD2 */
+                              "GPIO2_24"; /* GMAC1_TXD3 */
+                       function = "gmac1";
+                       bias-disable;
+                       drive-strength = <25>;
+                       input-disable;
+                       input-schmitt-disable;
+                       slew-rate = <0>;
+               };
+
+               rx-pins {
+                       pins = "GPIO2_19", /* GMAC1_RX_CLK */
+                              "GPIO2_25", /* GMAC1_RXDV */
+                              "GPIO2_30", /* GMAC1_RXD0 */
+                              "GPIO2_31", /* GMAC1_RXD1 */
+                              "GPIO3_0",  /* GMAC1_RXD2 */
+                              "GPIO3_1";  /* GMAC1_RXD3 */
+                       function = "gmac1";
+                       bias-disable;
+                       drive-strength = <1>;
+                       input-enable;
+                       input-schmitt-disable;
+                       slew-rate = <0>;
+               };
+       };
+
+       mdio1_pins: mdio1-0 {
+               mdc-pins {
+                       pins = "GMAC0_MDC";
+                       function = "gmac1";
+                       bias-disable;
+                       drive-strength = <13>;
+                       input-disable;
+                       input-schmitt-disable;
+                       slew-rate = <0>;
+               };
+
+               mdio-pins {
+                       pins = "GMAC0_MDIO";
+                       function = "gmac1";
+                       bias-disable;
+                       drive-strength = <13>;
+                       input-enable;
+                       input-schmitt-enable;
+                       slew-rate = <0>;
+               };
+       };
+};