GMAC_OP_MODE_SR
dwge_write(sc, GMAC_OP_MODE, mode | GMAC_OP_MODE_ST | GMAC_OP_MODE_SR);
dmactrl &= ~(GMAC_OP_MODE_ST | GMAC_OP_MODE_SR);
dwge_write(sc, GMAC_OP_MODE, mode & ~GMAC_OP_MODE_SR);