wifi: mac80211: add some support for RX OMI power saving

In order to save power, it can be desirable to change the
RX operating mode using OMI to reduce the bandwidth. As the
handshake must be done in the HTC+ field, it cannot be done
by mac80211 directly, so expose functions to the driver to
request and finalize the necessary updates.

Note that RX OMI really only changes what the peer (AP) will
transmit to us, but in order to use it to actually save some
power (by reducing the listen bandwidth) we also update rate
scaling and then the channel context's mindef accordingly.

The updates are split into two in order to sequence them
correctly, when reducing bandwidth first reduce the rate
scaling and thus TX, then send OMI, then reduce the listen
bandwidth (chandef); when increasing bandwidth this is the
other way around. This also requires tracking in different
variables which part is applicable already.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://patch.msgid.link/20250101070249.2c1a1934bd73.I4e90fd503504e37f9eac5bdae62e3f07e7071275@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 118 insertions, 1 deletions

diff --git a/net/mac80211/he.c b/net/mac80211/he.c
index ecbb042dd043..5792ef77e986 100644
--- a/net/mac80211/he.c
+++ b/net/mac80211/he.c
@@ -3,10 +3,11 @@
  * HE handling
  *
  * Copyright(c) 2017 Intel Deutschland GmbH
- * Copyright(c) 2019 - 2023 Intel Corporation
+ * Copyright(c) 2019 - 2024 Intel Corporation
  */
 
 #include "ieee80211_i.h"
+#include "rate.h"
 
 static void
 ieee80211_update_from_he_6ghz_capa(const struct ieee80211_he_6ghz_capa *he_6ghz_capa,
@@ -248,3 +249,119 @@ ieee80211_he_spr_ie_to_bss_conf(struct ieee80211_vif *vif,
 		he_obss_pd->enable = true;
 	}
 }
+
+static void ieee80211_link_sta_rc_update_omi(struct ieee80211_link_data *link,
+					     struct link_sta_info *link_sta)
+{
+	struct ieee80211_sub_if_data *sdata = link->sdata;
+	struct ieee80211_supported_band *sband;
+	enum ieee80211_sta_rx_bandwidth new_bw;
+	enum nl80211_band band;
+
+	band = link->conf->chanreq.oper.chan->band;
+	sband = sdata->local->hw.wiphy->bands[band];
+
+	new_bw = ieee80211_sta_cur_vht_bw(link_sta);
+	if (link_sta->pub->bandwidth == new_bw)
+		return;
+
+	link_sta->pub->bandwidth = new_bw;
+	rate_control_rate_update(sdata->local, sband, link_sta,
+				 IEEE80211_RC_BW_CHANGED);
+}
+
+bool ieee80211_prepare_rx_omi_bw(struct ieee80211_link_sta *pub_link_sta,
+				 enum ieee80211_sta_rx_bandwidth bw)
+{
+	struct sta_info *sta = container_of(pub_link_sta->sta,
+					    struct sta_info, sta);
+	struct ieee80211_local *local = sta->sdata->local;
+	struct link_sta_info *link_sta =
+		sdata_dereference(sta->link[pub_link_sta->link_id], sta->sdata);
+	struct ieee80211_link_data *link =
+		sdata_dereference(sta->sdata->link[pub_link_sta->link_id],
+				  sta->sdata);
+	struct ieee80211_chanctx_conf *conf;
+	struct ieee80211_chanctx *chanctx;
+	bool ret;
+
+	if (WARN_ON(!link || !link_sta || link_sta->pub != pub_link_sta))
+		return false;
+
+	conf = sdata_dereference(link->conf->chanctx_conf, sta->sdata);
+	if (WARN_ON(!conf))
+		return false;
+
+	trace_api_prepare_rx_omi_bw(local, sta->sdata, link_sta, bw);
+
+	chanctx = container_of(conf, typeof(*chanctx), conf);
+
+	if (link_sta->rx_omi_bw_staging == bw) {
+		ret = false;
+		goto trace;
+	}
+
+	/* must call this API in pairs */
+	if (WARN_ON(link_sta->rx_omi_bw_tx != link_sta->rx_omi_bw_staging ||
+		    link_sta->rx_omi_bw_rx != link_sta->rx_omi_bw_staging)) {
+		ret = false;
+		goto trace;
+	}
+
+	if (bw < link_sta->rx_omi_bw_staging) {
+		link_sta->rx_omi_bw_tx = bw;
+		ieee80211_link_sta_rc_update_omi(link, link_sta);
+	} else {
+		link_sta->rx_omi_bw_rx = bw;
+		ieee80211_recalc_chanctx_min_def(local, chanctx, NULL, false);
+	}
+
+	link_sta->rx_omi_bw_staging = bw;
+	ret = true;
+trace:
+	trace_api_return_bool(local, ret);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(ieee80211_prepare_rx_omi_bw);
+
+void ieee80211_finalize_rx_omi_bw(struct ieee80211_link_sta *pub_link_sta)
+{
+	struct sta_info *sta = container_of(pub_link_sta->sta,
+					    struct sta_info, sta);
+	struct ieee80211_local *local = sta->sdata->local;
+	struct link_sta_info *link_sta =
+		sdata_dereference(sta->link[pub_link_sta->link_id], sta->sdata);
+	struct ieee80211_link_data *link =
+		sdata_dereference(sta->sdata->link[pub_link_sta->link_id],
+				  sta->sdata);
+	struct ieee80211_chanctx_conf *conf;
+	struct ieee80211_chanctx *chanctx;
+
+	if (WARN_ON(!link || !link_sta || link_sta->pub != pub_link_sta))
+		return;
+
+	conf = sdata_dereference(link->conf->chanctx_conf, sta->sdata);
+	if (WARN_ON(!conf))
+		return;
+
+	trace_api_finalize_rx_omi_bw(local, sta->sdata, link_sta);
+
+	chanctx = container_of(conf, typeof(*chanctx), conf);
+
+	if (link_sta->rx_omi_bw_tx != link_sta->rx_omi_bw_staging) {
+		/* rate control in finalize only when widening bandwidth */
+		WARN_ON(link_sta->rx_omi_bw_tx > link_sta->rx_omi_bw_staging);
+		link_sta->rx_omi_bw_tx = link_sta->rx_omi_bw_staging;
+		ieee80211_link_sta_rc_update_omi(link, link_sta);
+	}
+
+	if (link_sta->rx_omi_bw_rx != link_sta->rx_omi_bw_staging) {
+		/* channel context in finalize only when narrowing bandwidth */
+		WARN_ON(link_sta->rx_omi_bw_rx < link_sta->rx_omi_bw_staging);
+		link_sta->rx_omi_bw_rx = link_sta->rx_omi_bw_staging;
+		ieee80211_recalc_chanctx_min_def(local, chanctx, NULL, false);
+	}
+
+	trace_api_return_void(local);
+}
+EXPORT_SYMBOL_GPL(ieee80211_finalize_rx_omi_bw);