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Zynq FSBL

As standard option Zynq FSBL for TE modules TE0720 does read and optionally display on primary UART console the MAC address that is stored on the module, this MAC Address is written to registers of the Primary Ethernet IP Core. If u-boot (or another second stage bootloader) does not overwrite it, then it will persist and be used in Linux (or other O/S) as well.

This is done in fsbl_hooks.c in the FsblHookBeforeHandoff function. When using TE supplied BSP's example design for Petalinux the FSBL code is already including this. When creating FSBL from scratch using Xilinx SDK Wizard then the hook code must be inserted manually (or the fsbl_hooks.c replaced completely). The way MAC Address is read from Hardware is module dependent, so proper files should be used.

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Xilinx u-boot and u-boot drivers for Zynq and MicroBlaze do not support any kind of reading of the MAC, they do not support the setting of MAC in Ethernet driver and they do not provide any means to add this functions without patching Xilinx u-boot source code.

Xilinx document UG983 explains how to set MAC address from u-boot prompt.

To disable u-boot to overwrite the MAC Address that was read and set in FSBL environment variable ethmacskip needs to be set. This prevents u-boot to write the MAC from environment into Ethernet Hardware.

As only option to use proper MAC Address (read from hardware MAC Address EEPROM in FSBL or other first stage bootloader) shared memory can be used. This method is supported by TE supplied FSBL hooks code. This MAC Address info is loaded into u-boot using a script - there is no need to patch u-boot source code.

/* PREBOOT */
#undef CONFIG_PREBOOT
#define CONFIG_PREBOOT<>"echo U-BOOT for ${hostname} preboot is loading environment from uEnv.txt; set autoexec echo; if mmc rescan; then if fatload mmc 0 0x01000000 uEnv.txt; then env import -t 0x01000000; fi; fi; "\

                        "echo importing env from FSBL shared area at 0xFFFFFC00; if itest *0xFFFFFC00 == 0xCAFEBABE; then env import -t 0xFFFFFC04; fi; echo running autoexec script; run autoexec"

Example use of the MAC Address import in u-boot