urtwn(4): improve RX filter

[avos]

Summary

• Filter out unneeded frames in STA mode.
• Implement ic_promisc() call.

Test Plan

Tested with RTL8188EU, STA and MONITOR modes.

[kevlo]

It seems that vendor drivers (rtl8188eu and rtl8188cu/rtl8192cu)
mess with both R92C_RXFLTMAP* and R92C_RCR.
I'd like to know more about the difference between RCR and R92C_RXFLTMAP*
registers.

If you tested it and it works fine for you, please commit it, thanks.

[avos]

In D3999#83473, @kevlo wrote:

It seems that vendor drivers (rtl8188eu and rtl8188cu/rtl8192cu)
mess with both R92C_RXFLTMAP* and R92C_RCR.
I'd like to know more about the difference between RCR and R92C_RXFLTMAP*
registers.

If you tested it and it works fine for you, please commit it, thanks.

R92C_RXFLTMAP* allows to receive some selected frame subtypes (each bit - 1 subtype; 1 - enable, 0 - disable).
R92C_A?F flags - unconditionally receive All Control / Data / Management Frames (i.e., contents of corresponding R92C_RXFLTMAP* will be ignored).

[adrian]

Please add the lock assertions and then yup, go ahead and commit it! THanks!

sys/dev/usb/wlan/if_urtwn.c

2788 ↗

(On Diff #9696)

Whilst here, also add a lock/unlock assert.

3169 ↗

(On Diff #9696)

Add a lock-assert call here if we're supposed to call it with the lock held.

(And if we're supposed to call it with the lock /not/ held, then add an unlock-assert.)

[avos]

• Add URTWN_ASSERT_LOCKED(sc) where needed.
• Sort local variables.

[avos]

In D3999#83480, @adrian wrote:

Please add the lock assertions and then yup, go ahead and commit it! THanks!

What about dependencies?

[adrian]

All good!