wifi: iwlwifi: mvm: move EMLSR/links code

The functions that are link related, so they should be in link.c and
not in mld-mac80211.c. Move them.
Also move the different prototypes to the right place in mvm.h

Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Link: https://msgid.link/20240416134215.e7c368256fa0.I6b15805a7c8a75d1814f1a829601daf4d3788731@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

drivers/net/wireless/intel/iwlwifi/mvm/link.c

@@ -501,3 +501,187 @@ unsigned int iwl_mvm_get_link_grade(struct ieee80211_bss_conf *link_conf)
 	return grade;
 }
 EXPORT_SYMBOL_IF_IWLWIFI_KUNIT(iwl_mvm_get_link_grade);
+
+/*
+ * This function receives a subset of the usable links bitmap and
+ * returns the primary link id, and -1 if such link doesn't exist
+ * (e.g. non-MLO connection) or wasn't found.
+ */
+int iwl_mvm_mld_get_primary_link(struct iwl_mvm *mvm,
+				 struct ieee80211_vif *vif,
+				 unsigned long usable_links)
+{
+	struct iwl_mvm_link_sel_data data[IEEE80211_MLD_MAX_NUM_LINKS];
+	u8 link_id, n_data = 0;
+
+	if (!ieee80211_vif_is_mld(vif) || !vif->cfg.assoc)
+		return -1;
+
+	for_each_set_bit(link_id, &usable_links, IEEE80211_MLD_MAX_NUM_LINKS) {
+		struct ieee80211_bss_conf *link_conf =
+			link_conf_dereference_protected(vif, link_id);
+
+		if (WARN_ON_ONCE(!link_conf))
+			continue;
+
+		data[n_data].link_id = link_id;
+		data[n_data].band = link_conf->chanreq.oper.chan->band;
+		data[n_data].width = link_conf->chanreq.oper.width;
+		data[n_data].active = true;
+		n_data++;
+	}
+
+	if (n_data <= 1)
+		return -1;
+
+	/* The logic should be modified to handle more than 2 links */
+	WARN_ON_ONCE(n_data > 2);
+
+	/* Primary link is the link with the wider bandwidth or higher band */
+	if (data[0].width > data[1].width)
+		return data[0].link_id;
+	if (data[0].width < data[1].width)
+		return data[1].link_id;
+	if (data[0].band >= data[1].band)
+		return data[0].link_id;
+
+	return data[1].link_id;
+}
+
+u8 iwl_mvm_set_link_selection_data(struct ieee80211_vif *vif,
+				   struct iwl_mvm_link_sel_data *data,
+				   unsigned long usable_links)
+{
+	u8 n_data = 0;
+	unsigned long link_id;
+
+	rcu_read_lock();
+
+	for_each_set_bit(link_id, &usable_links, IEEE80211_MLD_MAX_NUM_LINKS) {
+		struct ieee80211_bss_conf *link_conf =
+			rcu_dereference(vif->link_conf[link_id]);
+
+		if (WARN_ON_ONCE(!link_conf))
+			continue;
+
+		data[n_data].link_id = link_id;
+		data[n_data].band = link_conf->chanreq.oper.chan->band;
+		data[n_data].width = link_conf->chanreq.oper.width;
+		data[n_data].active = vif->active_links & BIT(link_id);
+		n_data++;
+	}
+
+	rcu_read_unlock();
+
+	return n_data;
+}
+
+bool iwl_mvm_mld_valid_link_pair(struct ieee80211_vif *vif,
+				 struct iwl_mvm_link_sel_data *a,
+				 struct iwl_mvm_link_sel_data *b)
+{
+	struct iwl_mvm_vif *mvmvif = iwl_mvm_vif_from_mac80211(vif);
+
+	if (a->band == b->band)
+		return false;
+
+	/* BT Coex effects eSR mode only if one of the link is on LB */
+	if (a->band == NL80211_BAND_2GHZ || b->band == NL80211_BAND_2GHZ)
+		return !(mvmvif->esr_disable_reason & IWL_MVM_ESR_DISABLE_COEX);
+
+	return true;
+}
+
+void iwl_mvm_mld_select_links(struct iwl_mvm *mvm, struct ieee80211_vif *vif,
+			      bool valid_links_changed)
+{
+	struct iwl_mvm_link_sel_data data[IEEE80211_MLD_MAX_NUM_LINKS];
+	unsigned long usable_links = ieee80211_vif_usable_links(vif);
+	u32 max_active_links = iwl_mvm_max_active_links(mvm, vif);
+	u16 new_active_links;
+	u8 n_data, i, j;
+
+	if (!IWL_MVM_AUTO_EML_ENABLE)
+		return;
+
+	/* The logic below is a simple version that doesn't suit more than 2
+	 * links
+	 */
+	WARN_ON_ONCE(max_active_links > 2);
+
+	/* if only a single active link is supported, assume that the one
+	 * selected by higher layer for connection establishment is the best.
+	 */
+	if (max_active_links == 1 && !valid_links_changed)
+		return;
+
+	/* If we are already using the maximal number of active links, don't do
+	 * any change. This can later be optimized to pick a 'better' link pair.
+	 */
+	if (hweight16(vif->active_links) == max_active_links)
+		return;
+
+	if (!iwl_mvm_esr_allowed_on_vif(mvm, vif))
+		return;
+
+	n_data = iwl_mvm_set_link_selection_data(vif, data, usable_links);
+
+	/* this is expected to be the current active link */
+	if (n_data == 1)
+		return;
+
+	new_active_links = 0;
+
+	/* Assume that after association only a single link is active, thus,
+	 * select only the 2nd link
+	 */
+	if (!valid_links_changed) {
+		for (i = 0; i < n_data; i++) {
+			if (data[i].active)
+				break;
+		}
+
+		if (WARN_ON_ONCE(i == n_data))
+			return;
+
+		for (j = 0; j < n_data; j++) {
+			if (i == j)
+				continue;
+
+			if (iwl_mvm_mld_valid_link_pair(vif, &data[i],
+							&data[j]))
+				break;
+		}
+
+		if (j != n_data)
+			new_active_links = BIT(data[i].link_id) |
+				BIT(data[j].link_id);
+	} else {
+		/* Try to find a valid link pair for EMLSR operation. If a pair
+		 * is not found continue using the current active link.
+		 */
+		for (i = 0; i < n_data; i++) {
+			for (j = 0; j < n_data; j++) {
+				if (i == j)
+					continue;
+
+				if (iwl_mvm_mld_valid_link_pair(vif, &data[i],
+								&data[j]))
+					break;
+			}
+
+			/* found a valid pair for EMLSR, use it */
+			if (j != n_data) {
+				new_active_links = BIT(data[i].link_id) |
+					BIT(data[j].link_id);
+				break;
+			}
+		}
+	}
+
+	if (!new_active_links)
+		return;
+
+	if (vif->active_links != new_active_links)
+		ieee80211_set_active_links_async(vif, new_active_links);
+}