minstrel_get_duration
u32 prob_dur = minstrel_get_duration(mi->max_prob_rate);
u32 tp_dur = minstrel_get_duration(mi->max_tp_rate[0]);
u32 tp2_dur = minstrel_get_duration(mi->max_tp_rate[1]);
tx_time_data = minstrel_get_duration(index) * ampdu_len / 1000;
duration = minstrel_get_duration(mi->max_tp_rate[0]);
if (minstrel_get_duration(mi->max_tp_rate[0]) > minstrel_get_duration(index) &&
duration = minstrel_get_duration(cur);
if (minstrel_get_duration(MI_RATE(group, i)) >= max_duration)
duration = minstrel_get_duration(index);