AR_TSF_L32
aic->aic_cal_start_time = REG_READ(ah, AR_TSF_L32);
tsf_lower = REG_READ(ah, AR_TSF_L32);
REG_WRITE(ah, AR_TSF_L32, tsf64 & 0xffffffff);
return REG_READ(ah, AR_TSF_L32);