U-Boot Ethernet Driver

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Last updated: Feb 24, 2021 by stephenm
8 min read


Table of Contents

Introduction

The gigabit Ethernet controller (GEM) implements a 10/100/1000 Mb/s Ethernet MAC that is compatible with the IEEE Standard for Ethernet (IEEE Std 802.3-2008) and capable of
operating in either half or full-duplex mode in 10/100 mode and full-duplex in 1000 mode. The processing system (PS) is equipped with four gigabit Ethernet controllers. Each
controller can be configured independently. Each controller uses a reduced gigabit media independent interface (RGMII) v2.0 (to save pins).

U-Boot Config

For ZynqMP:

CONFIG_ZYNQ_GEM=y
CONFIG_DM_ETH=y
CONFIG_NET_RANDOM_ETHADDR=y

For Zynq

CONFIG_ZYNQ_GEM=y
CONFIG_NET_RANDOM_ETHADDR=y

Device Tree


For ZynqMP

&gem3 {
       status = "okay";
       phy-handle = <&phy0>;
       phy-mode = "rgmii-id";
       pinctrl-names = "default";
       pinctrl-0 = <&pinctrl_gem3_default>;
       phy0: phy@21 {
               reg = <21>;
               ti,rx-internal-delay = <0x8>;
               ti,tx-internal-delay = <0xa>;
               ti,fifo-depth = <0x1>;
               ti,rxctrl-strap-worka;
       };
};
 
       pinctrl_gem3_default: gem3-default {
               mux {
                       function = "ethernet3";
                     groups = "ethernet3_0_grp";
               };
 
               conf {
                       groups = "ethernet3_0_grp";
                       slew-rate = <SLEW_RATE_SLOW>;
                       io-standard = <IO_STANDARD_LVCMOS18>;
               };
 
               conf-rx {
                       pins = "MIO70", "MIO71", "MIO72", "MIO73", "MIO74","MIO75";
                       bias-high-impedance;
                        low-power-disable;
               };
 
               conf-tx {
                       pins = "MIO64", "MIO65", "MIO66", "MIO67", "MIO68","MIO69";
                       bias-disable;
                       low-power-enable;
               };
 
               mux-mdio {
                       function = "mdio3";
                       groups = "mdio3_0_grp";
               };
 
               conf-mdio {
                       groups = "mdio3_0_grp";
                       slew-rate = <SLEW_RATE_SLOW>;
                       io-standard = <IO_STANDARD_LVCMOS18>;
                       bias-disable;
               };
       };

For Zynq

&gem0 {
       status = "okay";
       phy-mode = "rgmii-id";
       phy-handle = <&ethernet_phy>;
       pinctrl-names = "default";
       pinctrl-0 = <&pinctrl_gem0_default>;
 
       ethernet_phy: ethernet-phy@7 {
               reg = <7>;
               device_type = "ethernet-phy";
       };
};
 
       pinctrl_gem0_default: gem0-default {
               mux {
                       function = "ethernet0";
                       groups = "ethernet0_0_grp";
               };
 
              conf {
                       groups = "ethernet0_0_grp";
                       slew-rate = <0>;
                       io-standard = <4>;
               };
 
               conf-rx {
                      pins = "MIO22", "MIO23", "MIO24", "MIO25", "MIO26", "MIO27";
                       bias-high-impedance;
                       low-power-disable;
               };
 
               conf-tx {
                      pins = "MIO16", "MIO17", "MIO18", "MIO19", "MIO20", "MIO21";
                       low-power-enable;
                       bias-disable;
               };
 
               mux-mdio {
                       function = "mdio0";
                       groups = "mdio0_0_grp";
               };
 
               conf-mdio {
                       groups = "mdio0_0_grp";
                       slew-rate = <0>;
                       io-standard = <1>;
                       bias-disable;
               };
       };

Test Procedure

U-Boot 2018.01 Xilinx ZynqMP ZCU102 rev1.0
 
I2C:   ready
DRAM: 4 GiB
EL Level:       EL2
Chip ID:       zuunknow
** Bad device mmc 0 **
Using default environment
 
In:   serial@ff000000
Out:   serial@ff000000
Err:   serial@ff000000
Model: ZynqMP ZCU102 Rev1.0
Board: Xilinx ZynqMP
Bootmode: JTAG_MODE
Net:   ZYNQ GEM: ff0e0000, phyaddr c, interface rgmii-id
eth0: ethernet@ff0e0000
U-BOOT for xilinx-zcu102-2018_1
 
BOOTP broadcast 1
DHCP client bound to address 10.0.2.15 (3 ms)
Hit any key to stop autoboot: 0
ZynqMP> mii info
PHY 0x07: OUI = 0x5043, Model = 0x21, Rev = 0x00, 1000baseX, FDX
PHY 0x0C: OUI = 0x5043, Model = 0x21, Rev = 0x00, 1000baseX, FDX
ZynqMP>
ZynqMP> mii device
MII devices: 'eth0'
Current device: 'eth0'
ZynqMP>
ZynqMP> setenv <server_ip>
ZynqMP> ping <server_ip>

HW IP features

  • Speed support for 10/100/1000 Mbps
  • MAC loopback and PHY loopback
  • Partial store and forward option
  • Packet buffer option
  • Flow control - TX/RX pause
  • Checksum offload support, CRC checking, FCS stripping
  • Promiscuous mode, Broadcast mode
  • Collision detection and enforcement - this is an IP feature, no SW support required
  • MDIO support for PHY layer management
  • Multicasting support
  • VLAN tagged frames
  • Half duplex support
  • Programmable IPG
  • External FIFO interface
  • Wake on LAN
  • IEEE1588 support for ZynqMP
  • Jumbo frame size support for ZynqMP
  • 64 bit addressing for ZynqMP
  • Priority queue support for ZynqMP
  • PS SGMII support (hardwired to 1Gbps) is present in ZynqMP

Features supported in driver

(Functional HW IP and stack related features)
  • Speed support for 10/100/1000 Mbps with clock framework
  • MDIO support for PHY layer management
  • Multicasting support
  • IEEE1588 support for ZynqMP
  • Priority queue support for ZynqMP
  • PS SGMII support is present in ZynqMP and supported in the driver
  • This driver can be used with PL SGMII/1000BaseX driver on Zynq and ZynqMP
  • This driver can be used with gmii2rgmii converter driver
  • Fixed link support for ZynqMP(Not tested for Zynq).

Missing Features, Known Issues and Limitations

  • 64-bit addressing support

Fixed Link Support in ZynqMP

Following are the steps to verify fixed link support in ZynqMP.
  • Create a design with both GEM2 and GEM3 available and loop back one to the other as mention in below wiki
Zynq Ultrascale Fixed Link PS Ethernet Demo
  • Once the design is created export to sdk and create lwip echoserver application to run from R5 processor.
  • In this application just confirm that it uses GEM2 in file src/platform_config.h
  • In lwip echo server application linkerscript go and modify linker address to 0x10000000 such that it was not overwritten by FSBL or any other images.
  • Go to bsp and change bsp settings to select uart1.
  • Now got to the corresponding bsp and then to libsrc>lwip141>src>contrib>ports>xilinx>netif>xemacpsif_physpeed.c
  • Open the file emacpsif_physpeed.c and go to routine phy_setup.c, comment the line "link_speed=get_IEEE_phy_speed(xemacpsp, phy_addr);" and assign link_speed=1000; Note that same speed should be given in u-boot dts.
  • Now save and build it.
  • Create FSBL for this design from SDK.
  • Also create ATF and PMUFW.
  • Now build u-boot for zcu102 with below changes in dts
diff --git a/arch/arm/dts/zynqmp-zcu102-revA.dts b/arch/arm/dts/zynqmp-zcu102-revA.dts
index 5cbff57..db256e1 100644
--- a/arch/arm/dts/zynqmp-zcu102-revA.dts
+++ b/arch/arm/dts/zynqmp-zcu102-revA.dts
@@ -124,6 +124,11 @@
ti,fifo-depth = <0x1>;
ti,rxctrl-strap-worka;
};
+ fixed-link {
+ speed = <1000>;
+ full-duplex;
+ };
+
};
  • Create a bootable BOOT.BIN using bif with images (pmufw, fsbl, bitstream, lwipapp, atf, u-boot).
  • Copy the BOOT.BIN onto SD card and boot from SD on ZCU102 board.
  • Open com0 port and you should see lwip prints and wait for print "TCP echo server started @ port 7".
  • Now come back to u-boot prompt and set ipaddr as 192.168.1.1 using setenv.
  • Now, ping lwip echoserver running on R5 from u-boot and it should success as shown below u-boot log.
ZynqMP> setenv ipaddr 192.168.1.1
ZynqMP> ping 192.168.1.10
Using ethernet@ff0e0000 device
host 192.168.1.10 is alive

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