When a link is already up, the following sequence makes the kernel
block completely:

  ip link set dev eth0 down
  ip link set dev eth0 up

This is because on suspended phy, the following lines

  __lpc_eth_reset(pldat);
  __lpc_eth_init(pldat);

make the LPC ethernet core block (see LPC32x0 manual). The PHY needs to be
(re-)activated low-level first.
Signed-off-by: Roland Stigge <stigge@antcom.de>
Signed-off-by: David S. Miller <davem@davemloft.net>