Part Number: AM3354
Tool/software: Linux
Sir,
We have our custom board designed for 2 1Gbps ethernet ports over RGMII interface. we are using yocto based linux 3.12.
ksz9021 interfaced over rgmii2 bus is emac1 with id=1 and ksz9021 interface over rgmii1 bus is emac0 with id 2.
We have done modifications in our dts file for both emac0 and emac1 for pin mux and rgmii mode.
&am33xx_pinmux {
ethernet0_pins: pinmux_ethernet0 {
pinctrl-single,pins = <
0x114 (PIN_OUTPUT_PULLDOWN | MUX_MODE2) /* mii1_tx_en.rgmii1_tctl */
0x118 (PIN_INPUT_PULLDOWN | MUX_MODE2) /* mii1_rx_dv.rgmii1_rctl */
0x11c (PIN_OUTPUT_PULLDOWN | MUX_MODE2) /* mii1_txd3.rgmii1_td3 */
0x120 (PIN_OUTPUT_PULLDOWN | MUX_MODE2) /* mii1_txd2.rgmii1_td2 */
0x124 (PIN_OUTPUT_PULLDOWN | MUX_MODE2) /* mii1_txd1.rgmii1_td1 */
0x128 (PIN_OUTPUT_PULLDOWN | MUX_MODE2) /* mii1_txd0.rgmii1_td0 */
0x12c (PIN_OUTPUT_PULLDOWN | MUX_MODE2) /* mii1_tx_clk.rgmii1_tclk */
0x130 (PIN_INPUT_PULLDOWN | MUX_MODE2) /* mii1_rx_clk.rgmii1_rclk */
0x134 (PIN_INPUT_PULLDOWN | MUX_MODE2) /* mii1_rxd3.rgmii1_rd3 */
0x138 (PIN_INPUT_PULLDOWN | MUX_MODE2) /* mii1_rxd2.rgmii1_rd2 */
0x13c (PIN_INPUT_PULLDOWN | MUX_MODE2) /* mii1_rxd1.rgmii1_rd1 */
0x140 (PIN_INPUT_PULLDOWN | MUX_MODE2) /* mii1_rxd0.rgmii1_rd0 */
>;
};
mdio_pins: pinmux_mdio {
pinctrl-single,pins = <
/* MDIO */
0x148 (PIN_INPUT_PULLUP | SLEWCTRL_FAST | MUX_MODE0) /* mdio_data.mdio_data */
0x14c (PIN_OUTPUT_PULLUP | MUX_MODE0) /* mdio_clk.mdio_clk */
>;
};
};
&cpsw_emac0 {
phy_id = <&davinci_mdio>, <1>;
phy-mode = "rgmii";
dual_emac_res_vlan = <1>;
/* Register 260 (104h) – RGMII Clock and Control Pad Skew */
rxc-skew-ps = <1400>;
rxdv-skew-ps = <0>;
txc-skew-ps = <1400>;
txen-skew-ps = <0>;
/* Register 261 (105h) – RGMII RX Data Pad Skew */
rxd3-skew-ps = <0>;
rxd2-skew-ps = <0>;
rxd1-skew-ps = <0>;
rxd0-skew-ps = <0>;
/* Register 262 (106h) – RGMII TX Data Pad Skew */
txd3-skew-ps = <0>;
txd2-skew-ps = <0>;
txd1-skew-ps = <0>;
txd0-skew-ps = <0>;
status = "okay";
};
&davinci_mdio {
pinctrl-names = "default";
pinctrl-0 = <&mdio_pins>;
status = "okay";
};
&mac {
slaves = <1>;
pinctrl-names = "default";
pinctrl-0 = <ðernet0_pins>;
status = "okay";
};
/* Ethernet */
&am33xx_pinmux {
ethernet1_pins: pinmux_ethernet1 {
pinctrl-single,pins = <
0x40 (PIN_OUTPUT_PULLDOWN | MUX_MODE2) /* gpmc_a0.rgmii2_tctl */
0x44 (PIN_INPUT_PULLDOWN | MUX_MODE2) /* gpmc_a1.rgmii2_rctl */
0x48 (PIN_OUTPUT_PULLDOWN | MUX_MODE2) /* gpmc_a2.rgmii2_td3 */
0x4c (PIN_OUTPUT_PULLDOWN | MUX_MODE2) /* gpmc_a3.rgmii2_td2 */
0x50 (PIN_OUTPUT_PULLDOWN | MUX_MODE2) /* gpmc_a4.rgmii2_td1 */
0x54 (PIN_OUTPUT_PULLDOWN | MUX_MODE2) /* gpmc_a5.rgmii2_td0 */
0x58 (PIN_OUTPUT_PULLDOWN | MUX_MODE2) /* gpmc_a6.rgmii2_tclk */
0x5c (PIN_INPUT_PULLDOWN | MUX_MODE2) /* gpmc_a7.rgmii2_rclk */
0x60 (PIN_INPUT_PULLDOWN | MUX_MODE2) /* gpmc_a8.rgmii2_rd3 */
0x64 (PIN_INPUT_PULLDOWN | MUX_MODE2) /* gpmc_a9.rgmii2_rd2 */
0x68 (PIN_INPUT_PULLDOWN | MUX_MODE2) /* gpmc_a10.rgmii2_rd1 */
0x6c (PIN_INPUT_PULLDOWN | MUX_MODE2) /* gpmc_a11.rgmii2_rd0 */
>;
};
};
&cpsw_emac1 {
phy_id = <&davinci_mdio>, <2>;
phy-mode = "rgmii";
dual_emac_res_vlan = <2>;
/* Register 260 (104h) – RGMII Clock and Control Pad Skew */
rxc-skew-ps = <1400>;
rxdv-skew-ps = <0>;
txc-skew-ps = <1400>;
txen-skew-ps = <0>;
/* Register 261 (105h) – RGMII RX Data Pad Skew */
rxd3-skew-ps = <0>;
rxd2-skew-ps = <0>;
rxd1-skew-ps = <0>;
rxd0-skew-ps = <0>;
/* Register 262 (106h) – RGMII TX Data Pad Skew */
txd3-skew-ps = <0>;
txd2-skew-ps = <0>;
txd1-skew-ps = <0>;
txd0-skew-ps = <0>;
status = "okay";
};
&mac {
slaves = <2>;
pinctrl-names = "default";
pinctrl-0 = <ðernet0_pins ðernet1_pins>;
dual_emac;
status = "okay";
};
In hardware configurations, FOR RGMII2 (emac1), there is 22 ohms series termination resistors in TX lines and 33 ohms in RX lines. The trace length are matched within clock and data lines of tx and rx group. All trace length of rgmii2 is 40 mm. We are able to ping 10/100 and 1000 Mbps perfectly.
FOR RGMII1 (emac0), we used same configurations, there is 22 ohms series termination resistors in TX lines and 33 ohms in RX lines. The trace length are matched within clock and data lines of tx and rx group. All trace length of rgmii2 is 70 mm. We were not able to ping 10/100 and 1000 Mbps.
for RGMII1, Then we changed all termination resitors with 22 ohms. 10/100 mbps ping started perfectly but still 1000 Mbps was not pinging.
Thereafter, we changed all series termination resistors with 0 Ohms. Thereafter 1Gbps ping started but was breaking at every 3 to 4 pings. We changed skew value of rxc-skew-ps and txc-skew-ps to 3000 and 1Gbps ping started good.
But, due to removing termination resistors, our second ksz9021 on rgmii1 is getting overheated at approx 78 degrees C over 1Gbps communication.
Can you guide me why phy on emac0 (rgmii1) is not working with same hardware and software configurations as phy on emac1 (rgmii2) over 1Gbps and 10/100 Mbps.
