wifi: mac80211: introduce 'channel request'

For channel contexts, mac80211 currently uses the cfg80211
chandef struct (control channel, center freq(s), width) to
define towards drivers and internally how these behave. In
fact, there are _two_ such structs used, where the min_def
can reduce bandwidth according to the stations connected.

Unfortunately,  with EHT this is longer be sufficient,  at
least not for all hardware.  EHT requires that non-AP STAs
that are connected to an AP with a lower bandwidth than it
(the AP) advertises (e.g. 160 MHz STA connected to 320 MHz
AP) still be able to receive downlink OFDMA and respond to
trigger frames for uplink OFDMA  that specify the position
and bandwidth  for the non-AP STA  relative to the channel
the AP is using.  Therefore, they need to be aware of this,
and at least for some hardware (e.g. Intel) this awareness
is in the hardware. As a result, use of the "same" channel
may need to be split over  two channel contexts where they
differ by the AP being used.

As a first step,  introduce a concept of a channel request
('chanreq') for each interface,  to control the context it
requests.   This step does nothing but reorganise the code,
so that later the AP's chandef can be added to the request
in order to handle the EHT case described above.

Link: https://msgid.link/20240129194108.2e88e48bd2e9.I4256183debe975c5ed71621611206fdbb69ba330@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 10 insertions, 2 deletions

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 62c4b4d10bb4..dd8a66e9afd9 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -224,6 +224,14 @@ enum ieee80211_chanctx_change {
 };
 
 /**
+ * struct ieee80211_chan_req - A channel "request"
+ * @oper: channel definition to use for operation
+ */
+struct ieee80211_chan_req {
+	struct cfg80211_chan_def oper;
+};
+
+/**
  * struct ieee80211_chanctx_conf - channel context that vifs may be tuned to
  *
  * This is the driver-visible part. The ieee80211_chanctx
@@ -583,7 +591,7 @@ struct ieee80211_fils_discovery {
  * @mcast_rate: per-band multicast rate index + 1 (0: disabled)
  * @bssid: The BSSID for this BSS
  * @enable_beacon: whether beaconing should be enabled or not
- * @chandef: Channel definition for this BSS -- the hardware might be
+ * @chanreq: Channel request for this BSS -- the hardware might be
  *	configured a higher bandwidth than this BSS uses, for example.
  * @mu_group: VHT MU-MIMO group membership data
  * @ht_operation_mode: HT operation mode like in &struct ieee80211_ht_operation.
@@ -716,7 +724,7 @@ struct ieee80211_bss_conf {
 	u32 cqm_rssi_hyst;
 	s32 cqm_rssi_low;
 	s32 cqm_rssi_high;
-	struct cfg80211_chan_def chandef;
+	struct ieee80211_chan_req chanreq;
 	struct ieee80211_mu_group_data mu_group;
 	bool qos;
 	bool hidden_ssid;