This driver supports Designware Ethernet Controller provided by Synopsis.
  
  The driver is enabled by CONFIG_DESIGNWARE_ETH.
  
  The driver has been developed and tested on SPEAr platforms. By default, the
  MDIO interface works at 100/Full. #defining the below options in board
  configuration file changes this behavior.
  
  Call an subroutine from respective board/.../board.c
  designware_initialize(u32 id, ulong base_addr, u32 phy_addr);
  
  The various options suported by the driver are
  1. CONFIG_DW_ALTDESCRIPTOR
  	Define this to use the Alternate/Enhanced Descriptor configurations.
  1. CONFIG_DW_AUTONEG
  	Define this to autonegotiate with the host before proceeding with mac
  	level configuration. This obviates the definitions of CONFIG_DW_SPEED10M
  	and CONFIG_DW_DUPLEXHALF.
  2. CONFIG_DW_SPEED10M
  	Define this to change the default behavior from 100Mbps to 10Mbps.
  3. CONFIG_DW_DUPLEXHALF
  	Define this to change the default behavior from Full Duplex to Half.
  4. CONFIG_DW_SEARCH_PHY
  	Define this to search the phy address. This would overwrite the value
  	passed as 3rd arg from designware_initialize routine.