wifi: rtw89: early recognize FW feature to decide if chanctx

wifi: rtw89: early recognize FW feature to decide if chanctx

In current flow, FW is asynchronously loaded after alloc_hw(). It defers
the decision on FW feature map. It makes things difficult for us to decide
whether to hook chanctx ops, which should be decided while alloc_hw() is
calling. Still, asynchronous gets its advantages. So, we want to resolve
this without dropping them.

Based on multi-FW flag, RTW89_MFW_SIG, we can determine runtime FW is
multi-FW (MFW) or single FW (SFW). Both of them have a quite small chunk
for header at the head. The difference is that MFW doesn't describe version
code in its header while SFW does. So, we plan to extend MFW header for
version code. After that, in both cases, we can determine FW feature map by
just FW header. And, according to the map, we can decide chanctx.

So, we call request_partial_firmware_into_buf() to request a quite small
chunk before alloc_hw() to get a early FW feature map without affecting
things much and only use early map to decide whether to hook chanctx ops.

It means that if non-extended MFW is used at runtime, driver just acts
without chanctx as before. If extended MFW or SFW, which supports required
FW features, is used at runtime, driver can hook chanctx ops to mac80211 if
chip has configured support_chanctx_num > 0.

Besides, key point for now to support single one chanctx is whether HW scan
is supported at runtime. So, we configure all chip's support_chanctx_num to
1, and check if HW scan is supported at runtime via early FW feature map.

Signed-off-by: Zong-Zhe Yang <kevin_yang@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20220809104952.61355-14-pkshih@realtek.com