When implementing AXI Ethernet core, the following warning is issued:
The constraint that is causing the issue is in the <project>_ethernet_wrapper.ncf file generated by the tool:
This warning is due to the KEEP attribute being removed from HDL.
The KEEP attribute is required in an EDK+ISE flow but is not required in an EDK+Vivado flow.
Since there is a single database which the design is picked from, a fix can be part of only one flow.
For an EDK+ISE flow, the work-around is attached.
To apply the work-around:
1) Download the tri_mode_eth_mac_block_gmii.vhd attached to this Answer Record.
2) Go to <Xilinx Install Directory>\14.6\ISE_DS\EDK\hw\XilinxProcessorIPLib\pcores\axi_ethernet_soft_temac_wrap_v3_01_a\hdl\vhdl and replace the tri_mode_eth_mac_block_gmii.vhd with the one you just downloaded.
Note: Always make a backup of the original file.
8/22/2013 - Initial Release