xiaomi wb behavior:
1. 开机：打开writebooster enable（控制是否写入SLC ）, 打开writebooster flush during enable(控制是否flush during enable) , 关闭writebooster flush enable(控制是否flush during hibernate), 开机之后不操作这几个开关，
2. writebuffer type: Lun based
3. storage: samsung + ufs3.1
4. bAvailableWriteBoosterBufferSizer size always not checked after boot up (avail buffer size指的是占用current writebooster size的百分比)
5. bWriteBoosterBufferLifeTimeEst not checked after boot up
6. dCurrentWriteBoosterBufferSize not checked after boot up
7. ufshcd_exception_event_handler
(1) check exception event status after device execption event occur. if it is URGENT_BKOPS, then check bkops status , if bkops status >= 02h(initial bkops status after boot up), then enable fBackgroundOpsEn
(2) WRITEBOOSTER_FLUSH_NEEDED is not checked after boot up.
8. ufshcd_suspend:
(1) send sync cache command sync current data to medium
(2) if it pm state is runtime pm, then check bkops status, if bkops status >= 02h(initial bkops status after boot up), then enable fBackgroundOpsEn, otherwish disable fBackgroundOpsEn and update current bkops status to initial bkops status
(3)send START STOP UNIT Command command update ufs power mode to ufs sleep mode.
(4) send DME_HIBERNATE_ENTER command update link state to hibernate state.
8. ufshcd_resume
(1) send DME_HIBERNATE_EXIT command update link state to active state.
(2)send START STOP UNIT Command command update ufs power mode to ufs active mode
(3) check bkops status, if bkops status >= 02h(initial bkops status after boot up), then enable fBackgroundOpsEn, otherwish disable fBackgroundOpsEn and update current bkops status to initial bkops status