BWN_MACCTL_GMODE
ctl = BWN_READ_4(mac, BWN_MACCTL) & ~BWN_MACCTL_GMODE;
ctl |= BWN_MACCTL_GMODE;
v = BWN_READ_4(mac, BWN_MACCTL) | BWN_MACCTL_GMODE;
if (v != (BWN_MACCTL_GMODE | BWN_MACCTL_IHR_ON))
macctl |= BWN_MACCTL_GMODE;