RSSI calibration is done for three RSSI types 0-2 (maybe CCK/OFDM/N?)

steps to take

1. back up classifier control (lower three bits)
2. turn on waited, off CCK and OFDM in classifier control
3. back up Core 1 and Core 2 Clip1 threshold values

4. write Core 1 and Core 2 Clip1 threshold values (FIXME: hi16(.rodata)+0x30000->_5e04)

5. back up PHY (not radio Broadcom...) register 0x91
6. back up radio register 0x17

7. write 0x140 to PHY register 0x91

8. write 6 to radio register 0x17
9. back up PHY register 0x92
10. back up radio register 0x1b
11. write 0x140 to phy register 0x92
12. write 6 to radio register 0x1b
13. back up radio registers 0x18 and 0x1c
14. clear the lowest three bits in radio registers 0x18 and 0x1c
15. back up radio register 0x3
16. back up radio register 0x5
17. set RSSI selection to the given RSSI type for core 5 (?)
18. scale RSSI offset (FIXME, 0, 0, 0, 5, 0, rssi type)
19. scale RSSI offset (FIXME, 0, 0, 0, 5, 1, rssi type)
20. [FIXME: ...big loop and if mess...]
21. scale RSSI offset (FIXME, 0, ?, ?, ?, 0, rssi type)
22. restore the lower three bits of radio registers 0x18 and 0x1c
23. set RSSI selection to ...?? for core ...??
24. set RSSI selection to ...?? for core ...??
25. set RSSI selection to ...?? for core ...??
26. restore PHY register 0x91
27. restore PHY register 0x92
28. restore radio register 0x1b
29. restore classifier control
30. restore Core 1 and Core 2 Clip1 threshold values