iwlwifi/mld/link.c

// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
/*
 * Copyright (C) 2024-2025 Intel Corporation
 */

#include "constants.h"
#include "link.h"
#include "iface.h"
#include "mlo.h"
#include "hcmd.h"
#include "phy.h"
#include "fw/api/rs.h"
#include "fw/api/txq.h"
#include "fw/api/mac.h"

#include "fw/api/context.h"
#include "fw/dbg.h"

static int iwl_mld_send_link_cmd(struct iwl_mld *mld,
				 struct iwl_link_config_cmd *cmd,
				 enum iwl_ctxt_action action)
{
	int ret;

	lockdep_assert_wiphy(mld->wiphy);

	cmd->action = cpu_to_le32(action);
	ret = iwl_mld_send_cmd_pdu(mld,
				   WIDE_ID(MAC_CONF_GROUP, LINK_CONFIG_CMD),
				   cmd);
	if (ret)
		IWL_ERR(mld, "Failed to send LINK_CONFIG_CMD (action:%d): %d\n",
			action, ret);
	return ret;
}

static int iwl_mld_add_link_to_fw(struct iwl_mld *mld,
				  struct ieee80211_bss_conf *link_conf)
{
	struct ieee80211_vif *vif = link_conf->vif;
	struct iwl_mld_vif *mld_vif = iwl_mld_vif_from_mac80211(vif);
	struct iwl_mld_link *link = iwl_mld_link_from_mac80211(link_conf);
	struct iwl_link_config_cmd cmd = {};

	lockdep_assert_wiphy(mld->wiphy);

	if (WARN_ON(!link))
		return -EINVAL;

	cmd.link_id = cpu_to_le32(link->fw_id);
	cmd.mac_id = cpu_to_le32(mld_vif->fw_id);
	cmd.spec_link_id = link_conf->link_id;
	cmd.phy_id = cpu_to_le32(FW_CTXT_ID_INVALID);

	ether_addr_copy(cmd.local_link_addr, link_conf->addr);

	if (vif->type == NL80211_IFTYPE_ADHOC && link_conf->bssid)
		ether_addr_copy(cmd.ibss_bssid_addr, link_conf->bssid);

	return iwl_mld_send_link_cmd(mld, &cmd, FW_CTXT_ACTION_ADD);
}

/* Get the basic rates of the used band and add the mandatory ones */
static void iwl_mld_fill_rates(struct iwl_mld *mld,
			       struct ieee80211_bss_conf *link,
			       struct ieee80211_chanctx_conf *chan_ctx,
			       __le32 *cck_rates, __le32 *ofdm_rates)
{
	struct cfg80211_chan_def *chandef =
		iwl_mld_get_chandef_from_chanctx(mld, chan_ctx);
	struct ieee80211_supported_band *sband =
		mld->hw->wiphy->bands[chandef->chan->band];
	unsigned long basic = link->basic_rates;
	int lowest_present_ofdm = 100;
	int lowest_present_cck = 100;
	u32 cck = 0;
	u32 ofdm = 0;
	int i;

	for_each_set_bit(i, &basic, BITS_PER_LONG) {
		int hw = sband->bitrates[i].hw_value;

		if (hw >= IWL_FIRST_OFDM_RATE) {
			ofdm |= BIT(hw - IWL_FIRST_OFDM_RATE);
			if (lowest_present_ofdm > hw)
				lowest_present_ofdm = hw;
		} else {
			BUILD_BUG_ON(IWL_FIRST_CCK_RATE != 0);

			cck |= BIT(hw);
			if (lowest_present_cck > hw)
				lowest_present_cck = hw;
		}
	}

	/* Now we've got the basic rates as bitmaps in the ofdm and cck
	 * variables. This isn't sufficient though, as there might not
	 * be all the right rates in the bitmap. E.g. if the only basic
	 * rates are 5.5 Mbps and 11 Mbps, we still need to add 1 Mbps
	 * and 6 Mbps because the 802.11-2007 standard says in 9.6:
	 *
	 *    [...] a STA responding to a received frame shall transmit
	 *    its Control Response frame [...] at the highest rate in the
	 *    BSSBasicRateSet parameter that is less than or equal to the
	 *    rate of the immediately previous frame in the frame exchange
	 *    sequence ([...]) and that is of the same modulation class
	 *    ([...]) as the received frame. If no rate contained in the
	 *    BSSBasicRateSet parameter meets these conditions, then the
	 *    control frame sent in response to a received frame shall be
	 *    transmitted at the highest mandatory rate of the PHY that is
	 *    less than or equal to the rate of the received frame, and
	 *    that is of the same modulation class as the received frame.
	 *
	 * As a consequence, we need to add all mandatory rates that are
	 * lower than all of the basic rates to these bitmaps.
	 */

	if (lowest_present_ofdm > IWL_RATE_24M_INDEX)
		ofdm |= IWL_RATE_BIT_MSK(24) >> IWL_FIRST_OFDM_RATE;
	if (lowest_present_ofdm > IWL_RATE_12M_INDEX)
		ofdm |= IWL_RATE_BIT_MSK(12) >> IWL_FIRST_OFDM_RATE;
	/* 6M already there or needed so always add */
	ofdm |= IWL_RATE_BIT_MSK(6) >> IWL_FIRST_OFDM_RATE;

	/* CCK is a bit more complex with DSSS vs. HR/DSSS vs. ERP.
	 * Note, however:
	 *  - if no CCK rates are basic, it must be ERP since there must
	 *    be some basic rates at all, so they're OFDM => ERP PHY
	 *    (or we're in 5 GHz, and the cck bitmap will never be used)
	 *  - if 11M is a basic rate, it must be ERP as well, so add 5.5M
	 *  - if 5.5M is basic, 1M and 2M are mandatory
	 *  - if 2M is basic, 1M is mandatory
	 *  - if 1M is basic, that's the only valid ACK rate.
	 * As a consequence, it's not as complicated as it sounds, just add
	 * any lower rates to the ACK rate bitmap.
	 */
	if (lowest_present_cck > IWL_RATE_11M_INDEX)
		cck |= IWL_RATE_BIT_MSK(11) >> IWL_FIRST_CCK_RATE;
	if (lowest_present_cck > IWL_RATE_5M_INDEX)
		cck |= IWL_RATE_BIT_MSK(5) >> IWL_FIRST_CCK_RATE;
	if (lowest_present_cck > IWL_RATE_2M_INDEX)
		cck |= IWL_RATE_BIT_MSK(2) >> IWL_FIRST_CCK_RATE;
	/* 1M already there or needed so always add */
	cck |= IWL_RATE_BIT_MSK(1) >> IWL_FIRST_CCK_RATE;

	*cck_rates = cpu_to_le32((u32)cck);
	*ofdm_rates = cpu_to_le32((u32)ofdm);
}

static void iwl_mld_fill_protection_flags(struct iwl_mld *mld,
					  struct ieee80211_bss_conf *link,
					  __le32 *protection_flags)
{
	u8 protection_mode = link->ht_operation_mode &
				IEEE80211_HT_OP_MODE_PROTECTION;
	u8 ht_flag = LINK_PROT_FLG_HT_PROT | LINK_PROT_FLG_FAT_PROT;

	IWL_DEBUG_RATE(mld, "HT protection mode: %d\n", protection_mode);

	if (link->use_cts_prot)
		*protection_flags |= cpu_to_le32(LINK_PROT_FLG_TGG_PROTECT);

	/* See section 9.23.3.1 of IEEE 80211-2012.
	 * Nongreenfield HT STAs Present is not supported.
	 */
	switch (protection_mode) {
	case IEEE80211_HT_OP_MODE_PROTECTION_NONE:
		break;
	case IEEE80211_HT_OP_MODE_PROTECTION_NONMEMBER:
	case IEEE80211_HT_OP_MODE_PROTECTION_NONHT_MIXED:
		*protection_flags |= cpu_to_le32(ht_flag);
		break;
	case IEEE80211_HT_OP_MODE_PROTECTION_20MHZ:
		/* Protect when channel wider than 20MHz */
		if (link->chanreq.oper.width > NL80211_CHAN_WIDTH_20)
			*protection_flags |= cpu_to_le32(ht_flag);
		break;
	}
}

static u8 iwl_mld_mac80211_ac_to_fw_ac(enum ieee80211_ac_numbers ac)
{
	static const u8 mac80211_ac_to_fw[] = {
		AC_VO,
		AC_VI,
		AC_BE,
		AC_BK
	};

	return mac80211_ac_to_fw[ac];
}

static void iwl_mld_fill_qos_params(struct ieee80211_bss_conf *link,
				    struct iwl_ac_qos *ac, __le32 *qos_flags)
{
	struct iwl_mld_link *mld_link = iwl_mld_link_from_mac80211(link);

	/* no need to check mld_link since it is done in the caller */

	for (int mac_ac = 0; mac_ac < IEEE80211_NUM_ACS; mac_ac++) {
		u8 txf = iwl_mld_mac80211_ac_to_fw_tx_fifo(mac_ac);
		u8 fw_ac = iwl_mld_mac80211_ac_to_fw_ac(mac_ac);

		ac[fw_ac].cw_min =
			cpu_to_le16(mld_link->queue_params[mac_ac].cw_min);
		ac[fw_ac].cw_max =
			cpu_to_le16(mld_link->queue_params[mac_ac].cw_max);
		ac[fw_ac].edca_txop =
			cpu_to_le16(mld_link->queue_params[mac_ac].txop * 32);
		ac[fw_ac].aifsn = mld_link->queue_params[mac_ac].aifs;
		ac[fw_ac].fifos_mask = BIT(txf);
	}

	if (link->qos)
		*qos_flags |= cpu_to_le32(MAC_QOS_FLG_UPDATE_EDCA);

	if (link->chanreq.oper.width != NL80211_CHAN_WIDTH_20_NOHT)
		*qos_flags |= cpu_to_le32(MAC_QOS_FLG_TGN);
}

static bool iwl_mld_fill_mu_edca(struct iwl_mld *mld,
				 const struct iwl_mld_link *mld_link,
				 struct iwl_he_backoff_conf *trig_based_txf)
{
	for (int mac_ac = 0; mac_ac < IEEE80211_NUM_ACS; mac_ac++) {
		const struct ieee80211_he_mu_edca_param_ac_rec *mu_edca =
			&mld_link->queue_params[mac_ac].mu_edca_param_rec;
		u8 fw_ac = iwl_mld_mac80211_ac_to_fw_ac(mac_ac);

		if (!mld_link->queue_params[mac_ac].mu_edca)
			return false;

		trig_based_txf[fw_ac].cwmin =
			cpu_to_le16(mu_edca->ecw_min_max & 0xf);
		trig_based_txf[fw_ac].cwmax =
			cpu_to_le16((mu_edca->ecw_min_max & 0xf0) >> 4);
		trig_based_txf[fw_ac].aifsn =
			cpu_to_le16(mu_edca->aifsn & 0xf);
		trig_based_txf[fw_ac].mu_time =
			cpu_to_le16(mu_edca->mu_edca_timer);
	}
	return true;
}

static u8 iwl_mld_sta_rx_bw_to_fw(enum ieee80211_sta_rx_bandwidth bw)
{
	switch (bw) {
	default: /* potential future values not supported by this hw/driver */
	case IEEE80211_STA_RX_BW_20:
		return IWL_LINK_MODIFY_BW_20;
	case IEEE80211_STA_RX_BW_40:
		return IWL_LINK_MODIFY_BW_40;
	case IEEE80211_STA_RX_BW_80:
		return IWL_LINK_MODIFY_BW_80;
	case IEEE80211_STA_RX_BW_160:
		return IWL_LINK_MODIFY_BW_160;
	case IEEE80211_STA_RX_BW_320:
		return IWL_LINK_MODIFY_BW_320;
	}
}

static int _iwl_mld_change_link_in_fw(struct iwl_mld *mld,
				      struct ieee80211_bss_conf *link,
				      enum ieee80211_sta_rx_bandwidth bw,
				      u32 changes)
{
	struct iwl_mld_link *mld_link = iwl_mld_link_from_mac80211(link);
	struct ieee80211_vif *vif = link->vif;
	struct iwl_mld_vif *mld_vif = iwl_mld_vif_from_mac80211(vif);
	struct ieee80211_chanctx_conf *chan_ctx;
	struct iwl_link_config_cmd cmd = {};
	u32 flags = 0;

	lockdep_assert_wiphy(mld->wiphy);

	if (WARN_ON(!mld_link))
		return -EINVAL;

	cmd.link_id = cpu_to_le32(mld_link->fw_id);
	cmd.spec_link_id = link->link_id;
	cmd.mac_id = cpu_to_le32(mld_vif->fw_id);

	chan_ctx = wiphy_dereference(mld->wiphy, mld_link->chan_ctx);

	cmd.phy_id = cpu_to_le32(chan_ctx ?
		iwl_mld_phy_from_mac80211(chan_ctx)->fw_id :
		FW_CTXT_ID_INVALID);

	ether_addr_copy(cmd.local_link_addr, link->addr);

	cmd.active = cpu_to_le32(mld_link->active);

	if ((changes & LINK_CONTEXT_MODIFY_ACTIVE) && !mld_link->active &&
	    mld_link->silent_deactivation) {
		/* We are de-activating a link that is having CSA with
		 * immediate quiet in EMLSR. Tell the firmware not to send any
		 * frame.
		 */
		cmd.block_tx = 1;
		mld_link->silent_deactivation = false;
	}

	if (vif->type == NL80211_IFTYPE_ADHOC && link->bssid)
		ether_addr_copy(cmd.ibss_bssid_addr, link->bssid);

	/* Channel context is needed to get the rates */
	if (chan_ctx)
		iwl_mld_fill_rates(mld, link, chan_ctx, &cmd.cck_rates,
				   &cmd.ofdm_rates);

	cmd.cck_short_preamble = cpu_to_le32(link->use_short_preamble);
	cmd.short_slot = cpu_to_le32(link->use_short_slot);

	iwl_mld_fill_protection_flags(mld, link, &cmd.protection_flags);

	iwl_mld_fill_qos_params(link, cmd.ac, &cmd.qos_flags);

	cmd.bi = cpu_to_le32(link->beacon_int);
	cmd.dtim_interval = cpu_to_le32(link->beacon_int * link->dtim_period);

	if (changes & LINK_CONTEXT_MODIFY_BANDWIDTH)
		cmd.modify_bandwidth = iwl_mld_sta_rx_bw_to_fw(bw);

	/* Configure HE parameters only if HE is supported, and only after
	 * the parameters are set in mac80211 (meaning after assoc)
	 */
	if (!link->he_support || iwlwifi_mod_params.disable_11ax ||
	    (vif->type == NL80211_IFTYPE_STATION && !vif->cfg.assoc)) {
		changes &= ~LINK_CONTEXT_MODIFY_HE_PARAMS;
		goto send_cmd;
	}

	/* ap_sta may be NULL if we're disconnecting */
	if (mld_vif->ap_sta) {
		struct ieee80211_link_sta *link_sta =
			link_sta_dereference_check(mld_vif->ap_sta,
						   link->link_id);

		if (!WARN_ON(!link_sta) && link_sta->he_cap.has_he &&
		    link_sta->he_cap.he_cap_elem.mac_cap_info[5] &
		    IEEE80211_HE_MAC_CAP5_OM_CTRL_UL_MU_DATA_DIS_RX)
			cmd.ul_mu_data_disable = 1;
	}

	cmd.htc_trig_based_pkt_ext = link->htc_trig_based_pkt_ext;

	if (link->uora_exists) {
		cmd.rand_alloc_ecwmin = link->uora_ocw_range & 0x7;
		cmd.rand_alloc_ecwmax = (link->uora_ocw_range >> 3) & 0x7;
	}

	if (iwl_mld_fill_mu_edca(mld, mld_link, cmd.trig_based_txf))
		flags |= LINK_FLG_MU_EDCA_CW;

	cmd.bss_color = link->he_bss_color.color;

	if (!link->he_bss_color.enabled)
		flags |= LINK_FLG_BSS_COLOR_DIS;

	cmd.frame_time_rts_th = cpu_to_le16(link->frame_time_rts_th);

	/* Block 26-tone RU OFDMA transmissions */
	if (mld_link->he_ru_2mhz_block)
		flags |= LINK_FLG_RU_2MHZ_BLOCK;

	if (link->nontransmitted) {
		ether_addr_copy(cmd.ref_bssid_addr, link->transmitter_bssid);
		cmd.bssid_index = link->bssid_index;
	}

	/* The only EHT parameter is puncturing, and starting from PHY cmd
	 * version 6 - it is sent there. For older versions of the PHY cmd,
	 * puncturing is not needed at all.
	 */
	if (WARN_ON(changes & LINK_CONTEXT_MODIFY_EHT_PARAMS))
		changes &= ~LINK_CONTEXT_MODIFY_EHT_PARAMS;

send_cmd:
	cmd.modify_mask = cpu_to_le32(changes);
	cmd.flags = cpu_to_le32(flags);

	return iwl_mld_send_link_cmd(mld, &cmd, FW_CTXT_ACTION_MODIFY);
}

int iwl_mld_change_link_in_fw(struct iwl_mld *mld,
			      struct ieee80211_bss_conf *link,
			      u32 changes)
{
	if (WARN_ON(changes & LINK_CONTEXT_MODIFY_BANDWIDTH))
		changes &= ~LINK_CONTEXT_MODIFY_BANDWIDTH;

	return _iwl_mld_change_link_in_fw(mld, link, 0, changes);
}

int iwl_mld_change_link_omi_bw(struct iwl_mld *mld,
			       struct ieee80211_bss_conf *link,
			       enum ieee80211_sta_rx_bandwidth bw)
{
	return _iwl_mld_change_link_in_fw(mld, link, bw,
					  LINK_CONTEXT_MODIFY_BANDWIDTH);
}

int iwl_mld_activate_link(struct iwl_mld *mld,
			  struct ieee80211_bss_conf *link)
{
	struct iwl_mld_link *mld_link = iwl_mld_link_from_mac80211(link);
	int ret;

	lockdep_assert_wiphy(mld->wiphy);

	if (WARN_ON(!mld_link || mld_link->active))
		return -EINVAL;

	mld_link->rx_omi.exit_ts = jiffies;
	mld_link->active = true;

	ret = iwl_mld_change_link_in_fw(mld, link,
					LINK_CONTEXT_MODIFY_ACTIVE);
	if (ret)
		mld_link->active = false;

	return ret;
}

void iwl_mld_deactivate_link(struct iwl_mld *mld,
			     struct ieee80211_bss_conf *link)
{
	struct iwl_mld_link *mld_link = iwl_mld_link_from_mac80211(link);
	struct iwl_probe_resp_data *probe_data;

	lockdep_assert_wiphy(mld->wiphy);

	if (WARN_ON(!mld_link || !mld_link->active))
		return;

	iwl_mld_cancel_session_protection(mld, link->vif, link->link_id);

	/* If we deactivate the link, we will probably remove it, or switch
	 * channel. In both cases, the CSA or Notice of Absence information is
	 * now irrelevant. Remove the data here.
	 */
	probe_data = wiphy_dereference(mld->wiphy, mld_link->probe_resp_data);
	RCU_INIT_POINTER(mld_link->probe_resp_data, NULL);
	if (probe_data)
		kfree_rcu(probe_data, rcu_head);

	mld_link->active = false;

	iwl_mld_change_link_in_fw(mld, link, LINK_CONTEXT_MODIFY_ACTIVE);

	/* Now that the link is not active in FW, we don't expect any new
	 * notifications for it. Cancel the ones that are already pending
	 */
	iwl_mld_cancel_notifications_of_object(mld, IWL_MLD_OBJECT_TYPE_LINK,
					       mld_link->fw_id);
}

static void
iwl_mld_rm_link_from_fw(struct iwl_mld *mld, struct ieee80211_bss_conf *link)
{
	struct iwl_mld_link *mld_link = iwl_mld_link_from_mac80211(link);
	struct iwl_link_config_cmd cmd = {};

	lockdep_assert_wiphy(mld->wiphy);

	if (WARN_ON(!mld_link))
		return;

	cmd.link_id = cpu_to_le32(mld_link->fw_id);
	cmd.spec_link_id = link->link_id;
	cmd.phy_id = cpu_to_le32(FW_CTXT_ID_INVALID);

	iwl_mld_send_link_cmd(mld, &cmd, FW_CTXT_ACTION_REMOVE);
}

static void iwl_mld_omi_bw_update(struct iwl_mld *mld,
				  struct ieee80211_bss_conf *link_conf,
				  struct iwl_mld_link *mld_link,
				  struct ieee80211_link_sta *link_sta,
				  enum ieee80211_sta_rx_bandwidth bw,
				  bool ap_update)
{
	enum ieee80211_sta_rx_bandwidth apply_bw;

	mld_link->rx_omi.desired_bw = bw;

	/* Can't update OMI while already in progress, desired_bw was
	 * set so on FW notification the worker will see the change
	 * and apply new the new desired bw.
	 */
	if (mld_link->rx_omi.bw_in_progress)
		return;

	if (bw == IEEE80211_STA_RX_BW_MAX)
		apply_bw = ieee80211_chan_width_to_rx_bw(link_conf->chanreq.oper.width);
	else
		apply_bw = bw;

	if (!ap_update) {
		/* The update isn't due to AP tracking after leaving OMI,
		 * where the AP could increase BW and then we must tell
		 * it that we can do the increased BW as well, if we did
		 * update the chandef.
		 * In this case, if we want MAX, then we will need to send
		 * a new OMI to the AP if it increases its own bandwidth as
		 * we can (due to internal and FW limitations, and being
		 * worried the AP might break) only send to what we're doing
		 * at the moment. In this case, set last_max_bw; otherwise
		 * if we really want to decrease our bandwidth set it to 0
		 * to indicate no updates are needed if the AP changes.
		 */
		if (bw != IEEE80211_STA_RX_BW_MAX)
			mld_link->rx_omi.last_max_bw = apply_bw;
		else
			mld_link->rx_omi.last_max_bw = 0;
	} else {
		/* Otherwise, if we're already trying to do maximum and
		 * the AP is changing, set last_max_bw to the new max the
		 * AP is using, we'll only get to this code path if the
		 * new bandwidth of the AP is bigger than what we sent it
		 * previously. This avoids repeatedly sending updates if
		 * it changes bandwidth, only doing it once on an increase.
		 */
		mld_link->rx_omi.last_max_bw = apply_bw;
	}

	if (ieee80211_prepare_rx_omi_bw(link_sta, bw)) {
		mld_link->rx_omi.bw_in_progress = apply_bw;
		iwl_mld_change_link_omi_bw(mld, link_conf, apply_bw);
	}
}

static void iwl_mld_omi_bw_finished_work(struct wiphy *wiphy,
					 struct wiphy_work *work)
{
	struct ieee80211_hw *hw = wiphy_to_ieee80211_hw(wiphy);
	struct iwl_mld *mld = IWL_MAC80211_GET_MLD(hw);
	struct iwl_mld_link *mld_link =
		container_of(work, typeof(*mld_link), rx_omi.finished_work.work);
	enum ieee80211_sta_rx_bandwidth desired_bw, switched_to_bw;
	struct ieee80211_vif *vif = mld_link->vif;
	struct iwl_mld_vif *mld_vif = iwl_mld_vif_from_mac80211(vif);
	struct ieee80211_bss_conf *link_conf;
	struct ieee80211_link_sta *link_sta;

	if (!mld_vif->ap_sta)
		return;

	link_sta = wiphy_dereference(mld->wiphy,
				     mld_vif->ap_sta->link[mld_link->link_id]);
	if (WARN_ON_ONCE(!link_sta))
		return;

	link_conf = link_conf_dereference_protected(vif, link_sta->link_id);
	if (WARN_ON_ONCE(!link_conf))
		return;

	if (WARN_ON(!mld_link->rx_omi.bw_in_progress))
		return;

	desired_bw = mld_link->rx_omi.desired_bw;
	switched_to_bw = mld_link->rx_omi.bw_in_progress;

	ieee80211_finalize_rx_omi_bw(link_sta);
	mld_link->rx_omi.bw_in_progress = 0;

	if (desired_bw != switched_to_bw)
		iwl_mld_omi_bw_update(mld, link_conf, mld_link, link_sta,
				      desired_bw, false);
}

static struct ieee80211_vif *
iwl_mld_get_omi_bw_reduction_pointers(struct iwl_mld *mld,
				      struct ieee80211_link_sta **link_sta,
				      struct iwl_mld_link **mld_link)
{
	struct iwl_mld_vif *mld_vif;
	struct ieee80211_vif *vif;
	int n_link_stas = 0;

	*link_sta = NULL;

	if (mld->trans->trans_cfg->device_family < IWL_DEVICE_FAMILY_SC)
		return NULL;

	vif = iwl_mld_get_bss_vif(mld);
	if (!vif)
		return NULL;

	for (int i = 0; i < ARRAY_SIZE(mld->fw_id_to_link_sta); i++) {
		struct ieee80211_link_sta *tmp;

		tmp = wiphy_dereference(mld->wiphy, mld->fw_id_to_link_sta[i]);
		if (IS_ERR_OR_NULL(tmp))
			continue;

		n_link_stas++;
		*link_sta = tmp;
	}

	/* can't do anything if we have TDLS peers or EMLSR */
	if (n_link_stas != 1)
		return NULL;

	mld_vif = iwl_mld_vif_from_mac80211(vif);
	*mld_link = iwl_mld_link_dereference_check(mld_vif,
						   (*link_sta)->link_id);
	if (WARN_ON(!*mld_link))
		return NULL;

	return vif;
}

void iwl_mld_omi_ap_changed_bw(struct iwl_mld *mld,
			       struct ieee80211_bss_conf *link_conf,
			       enum ieee80211_sta_rx_bandwidth bw)
{
	struct ieee80211_link_sta *link_sta;
	struct iwl_mld_link *mld_link;
	struct ieee80211_vif *vif;

	vif = iwl_mld_get_omi_bw_reduction_pointers(mld, &link_sta, &mld_link);
	if (!vif)
		return;

	if (WARN_ON(link_conf->vif != vif))
		return;

	/* This is 0 if we requested an OMI BW reduction and don't want to
	 * be sending an OMI when the AP's bandwidth changes.
	 */
	if (!mld_link->rx_omi.last_max_bw)
		return;

	/* We only need to tell the AP if it increases BW over what we last
	 * told it we were using, if it reduces then our last OMI to it will
	 * not get used anyway (e.g. we said we want 160 but it's doing 80.)
	 */
	if (bw < mld_link->rx_omi.last_max_bw)
		return;

	iwl_mld_omi_bw_update(mld, link_conf, mld_link, link_sta, bw, true);
}

void iwl_mld_handle_omi_status_notif(struct iwl_mld *mld,
				     struct iwl_rx_packet *pkt)
{
	struct ieee80211_link_sta *link_sta;
	struct iwl_mld_link *mld_link;
	struct ieee80211_vif *vif;

	vif = iwl_mld_get_omi_bw_reduction_pointers(mld, &link_sta, &mld_link);
	if (IWL_FW_CHECK(mld, !vif, "unexpected OMI notification\n"))
		return;

	if (IWL_FW_CHECK(mld, !mld_link->rx_omi.bw_in_progress,
			 "OMI notification when not requested\n"))
		return;

	wiphy_delayed_work_queue(mld->hw->wiphy,
				 &mld_link->rx_omi.finished_work,
				 msecs_to_jiffies(IWL_MLD_OMI_AP_SETTLE_DELAY));
}

void iwl_mld_leave_omi_bw_reduction(struct iwl_mld *mld)
{
	struct ieee80211_bss_conf *link_conf;
	struct ieee80211_link_sta *link_sta;
	struct iwl_mld_link *mld_link;
	struct ieee80211_vif *vif;

	vif = iwl_mld_get_omi_bw_reduction_pointers(mld, &link_sta, &mld_link);
	if (!vif)
		return;

	link_conf = link_conf_dereference_protected(vif, link_sta->link_id);
	if (WARN_ON_ONCE(!link_conf))
		return;

	if (!link_conf->he_support)
		return;

	mld_link->rx_omi.exit_ts = jiffies;

	iwl_mld_omi_bw_update(mld, link_conf, mld_link, link_sta,
			      IEEE80211_STA_RX_BW_MAX, false);
}

void iwl_mld_check_omi_bw_reduction(struct iwl_mld *mld)
{
	enum ieee80211_sta_rx_bandwidth bw = IEEE80211_STA_RX_BW_MAX;
	struct ieee80211_chanctx_conf *chanctx;
	struct ieee80211_bss_conf *link_conf;
	struct ieee80211_link_sta *link_sta;
	struct cfg80211_chan_def chandef;
	struct iwl_mld_link *mld_link;
	struct iwl_mld_vif *mld_vif;
	struct ieee80211_vif *vif;
	struct iwl_mld_phy *phy;
	u16 punctured;
	int exit_thr;

	/* not allowed in CAM mode */
	if (iwlmld_mod_params.power_scheme == IWL_POWER_SCHEME_CAM)
		return;

	/* must have one BSS connection (no P2P), no TDLS, nor EMLSR */
	vif = iwl_mld_get_omi_bw_reduction_pointers(mld, &link_sta, &mld_link);
	if (!vif)
		return;

	link_conf = link_conf_dereference_protected(vif, link_sta->link_id);
	if (WARN_ON_ONCE(!link_conf))
		return;

	if (!link_conf->he_support)
		return;

	chanctx = wiphy_dereference(mld->wiphy, mld_link->chan_ctx);
	if (WARN_ON(!chanctx))
		return;

	mld_vif = iwl_mld_vif_from_mac80211(vif);
	if (!mld_vif->authorized)
		goto apply;

	/* must not be in low-latency mode */
	if (iwl_mld_vif_low_latency(mld_vif))
		goto apply;

	chandef = link_conf->chanreq.oper;

	switch (chandef.width) {
	case NL80211_CHAN_WIDTH_320:
		exit_thr = IWL_MLD_OMI_EXIT_CHAN_LOAD_320;
		break;
	case NL80211_CHAN_WIDTH_160:
		exit_thr = IWL_MLD_OMI_EXIT_CHAN_LOAD_160;
		break;
	default:
		/* since we reduce to 80 MHz, must have more to start with */
		goto apply;
	}

	/* not to be done if primary 80 MHz is punctured */
	if (cfg80211_chandef_primary(&chandef, NL80211_CHAN_WIDTH_80,
				     &punctured) < 0 ||
	    punctured != 0)
		goto apply;

	phy = iwl_mld_phy_from_mac80211(chanctx);

	if (phy->channel_load_by_us > exit_thr) {
		/* send OMI for max bandwidth */
		goto apply;
	}

	if (phy->channel_load_by_us > IWL_MLD_OMI_ENTER_CHAN_LOAD) {
		/* no changes between enter/exit thresholds */
		return;
	}

	if (time_is_after_jiffies(mld_link->rx_omi.exit_ts +
				  msecs_to_jiffies(IWL_MLD_OMI_EXIT_PROTECTION)))
		return;

	/* reduce bandwidth to 80 MHz to save power */
	bw = IEEE80211_STA_RX_BW_80;
apply:
	iwl_mld_omi_bw_update(mld, link_conf, mld_link, link_sta, bw, false);
}

IWL_MLD_ALLOC_FN(link, bss_conf)

/* Constructor function for struct iwl_mld_link */
static int
iwl_mld_init_link(struct iwl_mld *mld, struct ieee80211_bss_conf *link,
		  struct iwl_mld_link *mld_link)
{
	mld_link->vif = link->vif;
	mld_link->link_id = link->link_id;

	iwl_mld_init_internal_sta(&mld_link->bcast_sta);
	iwl_mld_init_internal_sta(&mld_link->mcast_sta);
	iwl_mld_init_internal_sta(&mld_link->aux_sta);

	wiphy_delayed_work_init(&mld_link->rx_omi.finished_work,
				iwl_mld_omi_bw_finished_work);

	return iwl_mld_allocate_link_fw_id(mld, &mld_link->fw_id, link);
}

/* Initializes the link structure, maps fw id to the ieee80211_bss_conf, and
 * adds a link to the fw
 */
int iwl_mld_add_link(struct iwl_mld *mld,
		     struct ieee80211_bss_conf *bss_conf)
{
	struct iwl_mld_vif *mld_vif = iwl_mld_vif_from_mac80211(bss_conf->vif);
	struct iwl_mld_link *link = iwl_mld_link_from_mac80211(bss_conf);
	bool is_deflink = bss_conf == &bss_conf->vif->bss_conf;
	int ret;

	if (!link) {
		if (is_deflink)
			link = &mld_vif->deflink;
		else
			link = kzalloc(sizeof(*link), GFP_KERNEL);
	} else {
		WARN_ON(!mld->fw_status.in_hw_restart);
	}

	ret = iwl_mld_init_link(mld, bss_conf, link);
	if (ret)
		goto free;

	rcu_assign_pointer(mld_vif->link[bss_conf->link_id], link);

	ret = iwl_mld_add_link_to_fw(mld, bss_conf);
	if (ret) {
		RCU_INIT_POINTER(mld->fw_id_to_bss_conf[link->fw_id], NULL);
		RCU_INIT_POINTER(mld_vif->link[bss_conf->link_id], NULL);
		goto free;
	}

	return ret;

free:
	if (!is_deflink)
		kfree(link);
	return ret;
}

/* Remove link from fw, unmap the bss_conf, and destroy the link structure */
void iwl_mld_remove_link(struct iwl_mld *mld,
			 struct ieee80211_bss_conf *bss_conf)
{
	struct iwl_mld_vif *mld_vif = iwl_mld_vif_from_mac80211(bss_conf->vif);
	struct iwl_mld_link *link = iwl_mld_link_from_mac80211(bss_conf);
	bool is_deflink = link == &mld_vif->deflink;

	if (WARN_ON(!link || link->active))
		return;

	iwl_mld_rm_link_from_fw(mld, bss_conf);
	/* Continue cleanup on failure */

	if (!is_deflink)
		kfree_rcu(link, rcu_head);

	RCU_INIT_POINTER(mld_vif->link[bss_conf->link_id], NULL);

	wiphy_delayed_work_cancel(mld->wiphy, &link->rx_omi.finished_work);

	if (WARN_ON(link->fw_id >= mld->fw->ucode_capa.num_links))
		return;

	RCU_INIT_POINTER(mld->fw_id_to_bss_conf[link->fw_id], NULL);
}

void iwl_mld_handle_missed_beacon_notif(struct iwl_mld *mld,
					struct iwl_rx_packet *pkt)
{
	const struct iwl_missed_beacons_notif *notif = (const void *)pkt->data;
	union iwl_dbg_tlv_tp_data tp_data = { .fw_pkt = pkt };
	u32 link_id = le32_to_cpu(notif->link_id);
	u32 missed_bcon = le32_to_cpu(notif->consec_missed_beacons);
	u32 missed_bcon_since_rx =
		le32_to_cpu(notif->consec_missed_beacons_since_last_rx);
	u32 scnd_lnk_bcn_lost =
		le32_to_cpu(notif->consec_missed_beacons_other_link);
	struct ieee80211_bss_conf *link_conf =
		iwl_mld_fw_id_to_link_conf(mld, link_id);
	u32 bss_param_ch_cnt_link_id;
	struct ieee80211_vif *vif;

	if (WARN_ON(!link_conf))
		return;

	vif = link_conf->vif;
	bss_param_ch_cnt_link_id = link_conf->bss_param_ch_cnt_link_id;

	IWL_DEBUG_INFO(mld,
		       "missed bcn link_id=%u, %u consecutive=%u\n",
		       link_id, missed_bcon, missed_bcon_since_rx);

	if (WARN_ON(!vif))
		return;

	mld->trans->dbg.dump_file_name_ext_valid = true;
	snprintf(mld->trans->dbg.dump_file_name_ext, IWL_FW_INI_MAX_NAME,
		 "LinkId_%d_MacType_%d", link_id,
		 iwl_mld_mac80211_iftype_to_fw(vif));

	iwl_dbg_tlv_time_point(&mld->fwrt,
			       IWL_FW_INI_TIME_POINT_MISSED_BEACONS, &tp_data);

	if (missed_bcon >= IWL_MLD_MISSED_BEACONS_THRESHOLD_LONG) {
		if (missed_bcon_since_rx >=
		    IWL_MLD_MISSED_BEACONS_SINCE_RX_THOLD) {
			ieee80211_connection_loss(vif);
			return;
		}
		IWL_WARN(mld,
			 "missed beacons exceeds threshold, but receiving data. Stay connected, Expect bugs.\n");
		return;
	}

	if (missed_bcon_since_rx > IWL_MLD_MISSED_BEACONS_THRESHOLD) {
		ieee80211_cqm_beacon_loss_notify(vif, GFP_ATOMIC);

		/* try to switch links, no-op if we don't have MLO */
		iwl_mld_int_mlo_scan(mld, vif);
	}

	/* no more logic if we're not in EMLSR */
	if (hweight16(vif->active_links) <= 1)
		return;

	/* We are processing a notification before link activation */
	if (le32_to_cpu(notif->other_link_id) == FW_CTXT_ID_INVALID)
		return;

	/* Exit EMLSR if we lost more than
	 * IWL_MLD_MISSED_BEACONS_EXIT_ESR_THRESH beacons on boths links
	 * OR more than IWL_MLD_BCN_LOSS_EXIT_ESR_THRESH on current link.
	 * OR more than IWL_MLD_BCN_LOSS_EXIT_ESR_THRESH_BSS_PARAM_CHANGED
	 * on current link and the link's bss_param_ch_count has changed on
	 * the other link's beacon.
	 */
	if ((missed_bcon >= IWL_MLD_BCN_LOSS_EXIT_ESR_THRESH_2_LINKS &&
	     scnd_lnk_bcn_lost >= IWL_MLD_BCN_LOSS_EXIT_ESR_THRESH_2_LINKS) ||
	    missed_bcon >= IWL_MLD_BCN_LOSS_EXIT_ESR_THRESH ||
	    (bss_param_ch_cnt_link_id != link_id &&
	     missed_bcon >=
	     IWL_MLD_BCN_LOSS_EXIT_ESR_THRESH_BSS_PARAM_CHANGED)) {
		iwl_mld_exit_emlsr(mld, vif, IWL_MLD_EMLSR_EXIT_MISSED_BEACON,
				   iwl_mld_get_primary_link(vif));
	}
}
EXPORT_SYMBOL_IF_IWLWIFI_KUNIT(iwl_mld_handle_missed_beacon_notif);

bool iwl_mld_cancel_missed_beacon_notif(struct iwl_mld *mld,
					struct iwl_rx_packet *pkt,
					u32 removed_link_id)
{
	struct iwl_missed_beacons_notif *notif = (void *)pkt->data;

	if (le32_to_cpu(notif->other_link_id) == removed_link_id) {
		/* Second link is being removed. Don't cancel the notification,
		 * but mark second link as invalid.
		 */
		notif->other_link_id = cpu_to_le32(FW_CTXT_ID_INVALID);
	}

	/* If the primary link is removed, cancel the notification */
	return le32_to_cpu(notif->link_id) == removed_link_id;
}

int iwl_mld_link_set_associated(struct iwl_mld *mld, struct ieee80211_vif *vif,
				struct ieee80211_bss_conf *link)
{
	return iwl_mld_change_link_in_fw(mld, link, LINK_CONTEXT_MODIFY_ALL &
					 ~(LINK_CONTEXT_MODIFY_ACTIVE |
					   LINK_CONTEXT_MODIFY_EHT_PARAMS));
}

struct iwl_mld_rssi_to_grade {
	s8 rssi[2];
	u16 grade;
};

#define RSSI_TO_GRADE_LINE(_lb, _hb_uhb, _grade) \
	{ \
		.rssi = {_lb, _hb_uhb}, \
		.grade = _grade \
	}

/*
 * This array must be sorted by increasing RSSI for proper functionality.
 * The grades are actually estimated throughput, represented as fixed-point
 * with a scale factor of 1/10.
 */
static const struct iwl_mld_rssi_to_grade rssi_to_grade_map[] = {
	RSSI_TO_GRADE_LINE(-85, -89, 172),
	RSSI_TO_GRADE_LINE(-83, -86, 344),
	RSSI_TO_GRADE_LINE(-82, -85, 516),
	RSSI_TO_GRADE_LINE(-80, -83, 688),
	RSSI_TO_GRADE_LINE(-77, -79, 1032),
	RSSI_TO_GRADE_LINE(-73, -76, 1376),
	RSSI_TO_GRADE_LINE(-70, -74, 1548),
	RSSI_TO_GRADE_LINE(-69, -72, 1720),
	RSSI_TO_GRADE_LINE(-65, -68, 2064),
	RSSI_TO_GRADE_LINE(-61, -66, 2294),
	RSSI_TO_GRADE_LINE(-58, -61, 2580),
	RSSI_TO_GRADE_LINE(-55, -58, 2868),
	RSSI_TO_GRADE_LINE(-46, -55, 3098),
	RSSI_TO_GRADE_LINE(-43, -54, 3442)
};

#define MAX_GRADE (rssi_to_grade_map[ARRAY_SIZE(rssi_to_grade_map) - 1].grade)

#define DEFAULT_CHAN_LOAD_2GHZ	30
#define DEFAULT_CHAN_LOAD_5GHZ	15
#define DEFAULT_CHAN_LOAD_6GHZ	0

/* Factors calculation is done with fixed-point with a scaling factor of 1/256 */
#define SCALE_FACTOR 256
#define MAX_CHAN_LOAD 256

static unsigned int
iwl_mld_get_n_subchannels(const struct ieee80211_bss_conf *link_conf)
{
	enum nl80211_chan_width chan_width =
		link_conf->chanreq.oper.width;
	int mhz = nl80211_chan_width_to_mhz(chan_width);
	unsigned int n_subchannels;

	if (WARN_ONCE(mhz < 20 || mhz > 320,
		      "Invalid channel width : (%d)\n", mhz))
		return 1;

	/* total number of subchannels */
	n_subchannels = mhz / 20;

	/* No puncturing if less than 80 MHz */
	if (mhz >= 80)
		n_subchannels -= hweight16(link_conf->chanreq.oper.punctured);

	return n_subchannels;
}

static int
iwl_mld_get_chan_load_from_element(struct iwl_mld *mld,
				   struct ieee80211_bss_conf *link_conf)
{
	struct ieee80211_vif *vif = link_conf->vif;
	const struct cfg80211_bss_ies *ies;
	const struct element *bss_load_elem = NULL;
	const struct ieee80211_bss_load_elem *bss_load;

	guard(rcu)();

	if (ieee80211_vif_link_active(vif, link_conf->link_id))
		ies = rcu_dereference(link_conf->bss->beacon_ies);
	else
		ies = rcu_dereference(link_conf->bss->ies);

	if (ies)
		bss_load_elem = cfg80211_find_elem(WLAN_EID_QBSS_LOAD,
						   ies->data, ies->len);

	if (!bss_load_elem ||
	    bss_load_elem->datalen != sizeof(*bss_load))
		return -EINVAL;

	bss_load = (const void *)bss_load_elem->data;

	return bss_load->channel_util;
}

static unsigned int
iwl_mld_get_chan_load_by_us(struct iwl_mld *mld,
			    struct ieee80211_bss_conf *link_conf,
			    bool expect_active_link)
{
	struct iwl_mld_link *mld_link = iwl_mld_link_from_mac80211(link_conf);
	struct ieee80211_chanctx_conf *chan_ctx;
	struct iwl_mld_phy *phy;

	if (!mld_link || !mld_link->active) {
		WARN_ON(expect_active_link);
		return 0;
	}

	if (WARN_ONCE(!rcu_access_pointer(mld_link->chan_ctx),
		      "Active link (%u) without channel ctxt assigned!\n",
		      link_conf->link_id))
		return 0;

	chan_ctx = wiphy_dereference(mld->wiphy, mld_link->chan_ctx);
	phy = iwl_mld_phy_from_mac80211(chan_ctx);

	return phy->channel_load_by_us;
}

/* Returns error if the channel utilization element is invalid/unavailable */
int iwl_mld_get_chan_load_by_others(struct iwl_mld *mld,
				    struct ieee80211_bss_conf *link_conf,
				    bool expect_active_link)
{
	int chan_load;
	unsigned int chan_load_by_us;

	/* get overall load */
	chan_load = iwl_mld_get_chan_load_from_element(mld, link_conf);
	if (chan_load < 0)
		return chan_load;

	chan_load_by_us = iwl_mld_get_chan_load_by_us(mld, link_conf,
						      expect_active_link);

	/* channel load by us is given in percentage */
	chan_load_by_us =
		NORMALIZE_PERCENT_TO_255(chan_load_by_us);

	/* Use only values that firmware sends that can possibly be valid */
	if (chan_load_by_us <= chan_load)
		chan_load -= chan_load_by_us;

	return chan_load;
}

static unsigned int
iwl_mld_get_default_chan_load(struct ieee80211_bss_conf *link_conf)
{
	enum nl80211_band band = link_conf->chanreq.oper.chan->band;

	switch (band) {
	case NL80211_BAND_2GHZ:
		return DEFAULT_CHAN_LOAD_2GHZ;
	case NL80211_BAND_5GHZ:
		return DEFAULT_CHAN_LOAD_5GHZ;
	case NL80211_BAND_6GHZ:
		return DEFAULT_CHAN_LOAD_6GHZ;
	default:
		WARN_ON(1);
		return 0;
	}
}

unsigned int iwl_mld_get_chan_load(struct iwl_mld *mld,
				   struct ieee80211_bss_conf *link_conf)
{
	int chan_load;

	chan_load = iwl_mld_get_chan_load_by_others(mld, link_conf, false);
	if (chan_load >= 0)
		return chan_load;

	/* No information from the element, take the defaults */
	chan_load = iwl_mld_get_default_chan_load(link_conf);

	/* The defaults are given in percentage */
	return NORMALIZE_PERCENT_TO_255(chan_load);
}

static unsigned int
iwl_mld_get_avail_chan_load(struct iwl_mld *mld,
			    struct ieee80211_bss_conf *link_conf)
{
	return MAX_CHAN_LOAD - iwl_mld_get_chan_load(mld, link_conf);
}

/* This function calculates the grade of a link. Returns 0 in error case */
unsigned int iwl_mld_get_link_grade(struct iwl_mld *mld,
				    struct ieee80211_bss_conf *link_conf)
{
	enum nl80211_band band;
	int rssi_idx;
	s32 link_rssi;
	unsigned int grade = MAX_GRADE;

	if (WARN_ON_ONCE(!link_conf))
		return 0;

	band = link_conf->chanreq.oper.chan->band;
	if (WARN_ONCE(band != NL80211_BAND_2GHZ &&
		      band != NL80211_BAND_5GHZ &&
		      band != NL80211_BAND_6GHZ,
		      "Invalid band (%u)\n", band))
		return 0;

	link_rssi = MBM_TO_DBM(link_conf->bss->signal);
	/*
	 * For 6 GHz the RSSI of the beacons is lower than
	 * the RSSI of the data.
	 */
	if (band == NL80211_BAND_6GHZ && link_rssi)
		link_rssi += 4;

	rssi_idx = band == NL80211_BAND_2GHZ ? 0 : 1;

	/* No valid RSSI - take the lowest grade */
	if (!link_rssi)
		link_rssi = rssi_to_grade_map[0].rssi[rssi_idx];

	IWL_DEBUG_EHT(mld,
		      "Calculating grade of link %d: band = %d, bandwidth = %d, punctured subchannels =0x%x RSSI = %d\n",
		      link_conf->link_id, band,
		      link_conf->chanreq.oper.width,
		      link_conf->chanreq.oper.punctured, link_rssi);

	/* Get grade based on RSSI */
	for (int i = 0; i < ARRAY_SIZE(rssi_to_grade_map); i++) {
		const struct iwl_mld_rssi_to_grade *line =
			&rssi_to_grade_map[i];

		if (link_rssi > line->rssi[rssi_idx])
			continue;
		grade = line->grade;
		break;
	}

	/* Apply the channel load and puncturing factors */
	grade = grade * iwl_mld_get_avail_chan_load(mld, link_conf) / SCALE_FACTOR;
	grade = grade * iwl_mld_get_n_subchannels(link_conf);

	IWL_DEBUG_EHT(mld, "Link %d's grade: %d\n", link_conf->link_id, grade);

	return grade;
}
EXPORT_SYMBOL_IF_IWLWIFI_KUNIT(iwl_mld_get_link_grade);