wifi: wfx: fix case where rates are out of order

When frames are sent over the air, the device always applies the data
rates in descending order. The driver assumed Minstrel also provided
rate in descending order.

However, in some cases, Minstrel can a choose a fallback rate greater
than the primary rate. In this case, the two rates was inverted, the
device try highest rate first and we get many retries.

Since the device always applies rates in descending order, the
workaround is to drop the rate when it higher than its predecessor in
the rate list. Thus [ 4, 5, 3 ] becomes [ 4, 3 ].

This patch has been tested in isolated room with a series of
attenuators. Here are the Minstrel statistics with 80dBm of attenuation:

Without the fix:

best ____________rate__________ ____statistics___ _____last____ ______sum-of________
mode guard # rate [name idx airtime max_tp] [avg(tp) avg(prob)] [retry|suc|att] [#success | #attempts]
HT20 LGI 1 S MCS0 0 1477 5.6 5.2 82.7 3 0 0 3 4
HT20 LGI 1 MCS1 1 738 10.6 0.0 0.0 0 0 0 0 1
HT20 LGI 1 D MCS2 2 492 14.9 13.5 81.5 5 0 0 5 9
HT20 LGI 1 C MCS3 3 369 18.8 17.6 84.3 5 0 0 76 96
HT20 LGI 1 A P MCS4 4 246 25.4 22.4 79.5 5 0 0 11268 14026
HT20 LGI 1 B S MCS5 5 185 30.7 19.7 57.7 5 8 9 3918 9793
HT20 LGI 1 MCS6 6 164 33.0 0.0 0.0 5 0 0 6 102
HT20 LGI 1 MCS7 7 148 35.1 0.0 0.0 0 0 0 0 44

With the fix:

best ____________rate__________ ____statistics___ _____last____ ______sum-of________
mode guard # rate [name idx airtime max_tp] [avg(tp) avg(prob)] [retry|suc|att] [#success | #attempts]
HT20 LGI 1 S MCS0 0 1477 5.6 1.8 28.6 1 0 0 1 5
HT20 LGI 1 DP MCS1 1 738 10.6 9.7 82.6 4 0 0 14 34
HT20 LGI 1 MCS2 2 492 14.9 9.2 55.4 5 0 0 52 77
HT20 LGI 1 B S MCS3 3 369 18.8 15.6 74.9 5 1 1 417 554
HT20 LGI 1 A MCS4 4 246 25.4 16.7 59.2 5 1 1 13812 17951
HT20 LGI 1 C S MCS5 5 185 30.7 14.0 41.0 5 1 5 57 640
HT20 LGI 1 MCS6 6 164 33.0 0.0 0.0 0 0 1 0 48
HT20 LGI 1 S MCS7 7 148 35.1 0.0 0.0 0 0 0 0 36

We can notice the device try now to send with lower rates (and high
success rates). At the end, we measured 20-25% better throughput with
this patch.

Fixes: 9bca45f3d692 ("staging: wfx: allow to send 802.11 frames")
Tested-by: Olivier Souloumiac <olivier.souloumiac@silabs.com>
Tested-by: Alexandr Suslenko <suslenko.o@ajax.systems>
Reported-by: Alexandr Suslenko <suslenko.o@ajax.systems>
Co-developed-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Signed-off-by: Felipe Negrelli Wolter <felipe.negrelliwolter@silabs.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20231004123039.157112-1-jerome.pouiller@silabs.com

wifi: wfx: allow to send frames during ROC

Until now, all the traffic was blocked during scan operation. However,
scan operation is going to be used to implement Remain On Channel (ROC).
In this case, special frames (marked with IEEE80211_TX_CTL_TX_OFFCHAN)
must be sent during the operation.

These frames need to be sent on the virtual interface #2. Until now,
this interface was only used by the device for internal purpose. But
since API 3.9, it can be used to send data during scan operation (we
hijack the scan process to implement ROC).

Thus, we need to change a bit the way we match the frames with the
interface.

Fortunately, the frames received during the scan are marked with the
correct interface number. So there is no change to do on this part.

Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20231004172843.195332-8-jerome.pouiller@silabs.com

wifi: wfx: move wfx_skb_*() out of the header file

There is no real reasons to keep these function in the header file.

Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20231004172843.195332-4-jerome.pouiller@silabs.com

wfx: use container_of() to get vif

Currently, upon virtual interface creation, wfx_add_interface() stores
a reference to the corresponding struct ieee80211_vif in private data,
for later usage. This is not needed when using the container_of
construct. This construct already has all the info it needs to retrieve
the reference to the corresponding struct from the offset that is
already available, inherent in container_of(), between its type and
member inputs (struct ieee80211_vif and drv_priv, respectively).
Remove vif (which was previously storing the reference to the struct
ieee80211_vif) from the struct wfx_vif, define a function
wvif_to_vif(wvif) for container_of(), and replace all wvif->vif with
the newly defined container_of construct.

Signed-off-by: Jaehee Park <jhpark1013@gmail.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20220506170046.GA1297231@jaehee-ThinkPad-X1-Extreme

wfx: get out from the staging area

The wfx driver is now mature enough to leave the staging area.

Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>