For QoS/WMM (EDCA) a mac80211 driver needs to have at least four queues. mac80211 will then program the queues according to the advertised access parameters.
Legend:
MQ: mac80211 queue
AC: Access Class
ACI: Access Class Index
mac80211 queue mapping:
AC 
MQ 
BK 
3 
BE 
2 
VI 
1 
VO 
0 
802.11 uses the following number scheme (cf. Table 736)
AC 
ACI 
BK 
01 (1) 
BE 
00 (0) 
VI 
10 (2) 
VO 
11 (3) 
Therefore, we have:
AC 
ACI 
MQ 
BK 
1 
3 
BE 
0 
2 
VI 
2 
1 
VO 
3 
0 
Due to internal collisions (we don't really know what this means either) the queue numbering is important, and queue 0 is highest priority, 3 lowest. If your hardware has a different idea of queue priority, you may need to rewrite the queue number, but make sure to do it everywhere mac80211 passes a queue number (conf_tx, skb_get_queue_mapping).
The user priority is used as follows (802.112007 table 91):
UP 
AC 
Priority 
1 
BK 
Lowest 
2 
BK 
. 
0 
BE 
. 
3 
BE 
. 
4 
VI 
. 
5 
VI 
. 
6 
VO 
. 
7 
VO 
Highest 
TOS:
mac80211 currently determines the UP based only on the IPv4 TOS field, unless the packet priority is set to 256..263 with setsockopt(SO_PRIORITY), in which case this maps directly to the UP (priority  256) for testing.
The IPv4 TOS field maps into the UP as follows, but keep in mind that the lowest two bits of the TOS are reserved (or used for ECN):
TOS 
UP 
0  31 
0 
32  63 
1 
... 

224  255 
7 
DSCP (RFC 2474):
Alternatively you can set the IP_TOS with setsockopt, then you need to ask how DSCP maps into the UP. DSCP is defined in the Differentiated Services (DiffServ) model as the six most significant bits of the DiffServ(DS) Field.
DS5 (P2) 
DS4 (P1) 
DS3 (P0) 
DS2 
DS1 
DS0 
ECN 
ECN 
The classes of DSCP in wide usage are:
DSCP Class 
Codepoint(s) 
Default 
0x00 
Expedited Forwarding (EF) 
0x2E 
Assured Forwarding (AF1) 
0xA, 0xC, 0xE 
Assured Forwarding (AF2) 
0x12, 0x14, 0x16 
Assured Forwarding (AF3) 
0x1A, 0x1C, 0x1E 
Assured Forwarding (AF4) 
0x22, 0x24, 0x26 
The 3 Precedence bits of DSCP (P2, P1, P0) are used for mapping to 802.1D tags and AC values as:
P2 P1 P0 
802.1D 
AC 
0 0 0 
0 
BE 
0 0 1 
1 
BK 
0 1 0 
2 
BK 
0 1 1 
3 
BE 
1 0 0 
4 
VI 
1 0 1 
5 
VI 
1 1 0 
6 
VO 
1 1 1 
7 
VO 