1 files changed, 837 insertions, 0 deletions

diff --git a/drivers/staging/wfx/data_tx.c b/drivers/staging/wfx/data_tx.c
new file mode 100644
index 000000000000..b722e9773232
--- /dev/null
+++ b/drivers/staging/wfx/data_tx.c
@@ -0,0 +1,837 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Datapath implementation.
+ *
+ * Copyright (c) 2017-2019, Silicon Laboratories, Inc.
+ * Copyright (c) 2010, ST-Ericsson
+ */
+#include <net/mac80211.h>
+
+#include "data_tx.h"
+#include "wfx.h"
+#include "bh.h"
+#include "sta.h"
+#include "queue.h"
+#include "debug.h"
+#include "traces.h"
+#include "hif_tx_mib.h"
+
+#define WFX_INVALID_RATE_ID (0xFF)
+#define WFX_LINK_ID_NO_ASSOC   15
+#define WFX_LINK_ID_GC_TIMEOUT ((unsigned long)(10 * HZ))
+
+static int wfx_get_hw_rate(struct wfx_dev *wdev,
+			   const struct ieee80211_tx_rate *rate)
+{
+	if (rate->idx < 0)
+		return -1;
+	if (rate->flags & IEEE80211_TX_RC_MCS) {
+		if (rate->idx > 7) {
+			WARN(1, "wrong rate->idx value: %d", rate->idx);
+			return -1;
+		}
+		return rate->idx + 14;
+	}
+	// WFx only support 2GHz, else band information should be retrieved
+	// from ieee80211_tx_info
+	return wdev->hw->wiphy->bands[NL80211_BAND_2GHZ]->bitrates[rate->idx].hw_value;
+}
+
+/* TX policy cache implementation */
+
+static void wfx_tx_policy_build(struct wfx_vif *wvif, struct tx_policy *policy,
+				struct ieee80211_tx_rate *rates)
+{
+	int i;
+	size_t count;
+	struct wfx_dev *wdev = wvif->wdev;
+
+	WARN(rates[0].idx < 0, "invalid rate policy");
+	memset(policy, 0, sizeof(*policy));
+	for (i = 1; i < IEEE80211_TX_MAX_RATES; i++)
+		if (rates[i].idx < 0)
+			break;
+	count = i;
+
+	/* HACK!!! Device has problems (at least) switching from
+	 * 54Mbps CTS to 1Mbps. This switch takes enormous amount
+	 * of time (100-200 ms), leading to valuable throughput drop.
+	 * As a workaround, additional g-rates are injected to the
+	 * policy.
+	 */
+	if (count == 2 && !(rates[0].flags & IEEE80211_TX_RC_MCS) &&
+	    rates[0].idx > 4 && rates[0].count > 2 &&
+	    rates[1].idx < 2) {
+		int mid_rate = (rates[0].idx + 4) >> 1;
+
+		/* Decrease number of retries for the initial rate */
+		rates[0].count -= 2;
+
+		if (mid_rate != 4) {
+			/* Keep fallback rate at 1Mbps. */
+			rates[3] = rates[1];
+
+			/* Inject 1 transmission on lowest g-rate */
+			rates[2].idx = 4;
+			rates[2].count = 1;
+			rates[2].flags = rates[1].flags;
+
+			/* Inject 1 transmission on mid-rate */
+			rates[1].idx = mid_rate;
+			rates[1].count = 1;
+
+			/* Fallback to 1 Mbps is a really bad thing,
+			 * so let's try to increase probability of
+			 * successful transmission on the lowest g rate
+			 * even more
+			 */
+			if (rates[0].count >= 3) {
+				--rates[0].count;
+				++rates[2].count;
+			}
+
+			/* Adjust amount of rates defined */
+			count += 2;
+		} else {
+			/* Keep fallback rate at 1Mbps. */
+			rates[2] = rates[1];
+
+			/* Inject 2 transmissions on lowest g-rate */
+			rates[1].idx = 4;
+			rates[1].count = 2;
+
+			/* Adjust amount of rates defined */
+			count += 1;
+		}
+	}
+
+	for (i = 0; i < IEEE80211_TX_MAX_RATES; ++i) {
+		int rateid;
+		u8 count;
+
+		if (rates[i].idx < 0)
+			break;
+		WARN_ON(rates[i].count > 15);
+		rateid = wfx_get_hw_rate(wdev, &rates[i]);
+		// Pack two values in each byte of policy->rates
+		count = rates[i].count;
+		if (rateid % 2)
+			count <<= 4;
+		policy->rates[rateid / 2] |= count;
+	}
+}
+
+static bool tx_policy_is_equal(const struct tx_policy *a,
+			       const struct tx_policy *b)
+{
+	return !memcmp(a->rates, b->rates, sizeof(a->rates));
+}
+
+static int wfx_tx_policy_find(struct tx_policy_cache *cache,
+			      struct tx_policy *wanted)
+{
+	struct tx_policy *it;
+
+	list_for_each_entry(it, &cache->used, link)
+		if (tx_policy_is_equal(wanted, it))
+			return it - cache->cache;
+	list_for_each_entry(it, &cache->free, link)
+		if (tx_policy_is_equal(wanted, it))
+			return it - cache->cache;
+	return -1;
+}
+
+static void wfx_tx_policy_use(struct tx_policy_cache *cache,
+			      struct tx_policy *entry)
+{
+	++entry->usage_count;
+	list_move(&entry->link, &cache->used);
+}
+
+static int wfx_tx_policy_release(struct tx_policy_cache *cache,
+				 struct tx_policy *entry)
+{
+	int ret = --entry->usage_count;
+
+	if (!ret)
+		list_move(&entry->link, &cache->free);
+	return ret;
+}
+
+static int wfx_tx_policy_get(struct wfx_vif *wvif,
+			     struct ieee80211_tx_rate *rates,
+			     bool *renew)
+{
+	int idx;
+	struct tx_policy_cache *cache = &wvif->tx_policy_cache;
+	struct tx_policy wanted;
+
+	wfx_tx_policy_build(wvif, &wanted, rates);
+
+	spin_lock_bh(&cache->lock);
+	if (WARN_ON(list_empty(&cache->free))) {
+		spin_unlock_bh(&cache->lock);
+		return WFX_INVALID_RATE_ID;
+	}
+	idx = wfx_tx_policy_find(cache, &wanted);
+	if (idx >= 0) {
+		*renew = false;
+	} else {
+		struct tx_policy *entry;
+		*renew = true;
+		/* If policy is not found create a new one
+		 * using the oldest entry in "free" list
+		 */
+		entry = list_entry(cache->free.prev, struct tx_policy, link);
+		memcpy(entry->rates, wanted.rates, sizeof(entry->rates));
+		entry->uploaded = 0;
+		entry->usage_count = 0;
+		idx = entry - cache->cache;
+	}
+	wfx_tx_policy_use(cache, &cache->cache[idx]);
+	if (list_empty(&cache->free)) {
+		/* Lock TX queues. */
+		wfx_tx_queues_lock(wvif->wdev);
+	}
+	spin_unlock_bh(&cache->lock);
+	return idx;
+}
+
+static void wfx_tx_policy_put(struct wfx_vif *wvif, int idx)
+{
+	int usage, locked;
+	struct tx_policy_cache *cache = &wvif->tx_policy_cache;
+
+	spin_lock_bh(&cache->lock);
+	locked = list_empty(&cache->free);
+	usage = wfx_tx_policy_release(cache, &cache->cache[idx]);
+	if (locked && !usage) {
+		/* Unlock TX queues. */
+		wfx_tx_queues_unlock(wvif->wdev);
+	}
+	spin_unlock_bh(&cache->lock);
+}
+
+static int wfx_tx_policy_upload(struct wfx_vif *wvif)
+{
+	int i;
+	struct tx_policy_cache *cache = &wvif->tx_policy_cache;
+	struct hif_mib_set_tx_rate_retry_policy *arg =
+		kzalloc(struct_size(arg,
+				    tx_rate_retry_policy,
+				    HIF_MIB_NUM_TX_RATE_RETRY_POLICIES),
+			GFP_KERNEL);
+	struct hif_mib_tx_rate_retry_policy *dst;
+
+	spin_lock_bh(&cache->lock);
+	/* Upload only modified entries. */
+	for (i = 0; i < HIF_MIB_NUM_TX_RATE_RETRY_POLICIES; ++i) {
+		struct tx_policy *src = &cache->cache[i];
+
+		if (!src->uploaded && memzcmp(src->rates, sizeof(src->rates))) {
+			dst = arg->tx_rate_retry_policy +
+				arg->num_tx_rate_policies;
+
+			dst->policy_index = i;
+			dst->short_retry_count = 255;
+			dst->long_retry_count = 255;
+			dst->first_rate_sel = 1;
+			dst->terminate = 1;
+			dst->count_init = 1;
+			memcpy(&dst->rates, src->rates, sizeof(src->rates));
+			src->uploaded = 1;
+			arg->num_tx_rate_policies++;
+		}
+	}
+	spin_unlock_bh(&cache->lock);
+	hif_set_tx_rate_retry_policy(wvif, arg);
+	kfree(arg);
+	return 0;
+}
+
+static void wfx_tx_policy_upload_work(struct work_struct *work)
+{
+	struct wfx_vif *wvif =
+		container_of(work, struct wfx_vif, tx_policy_upload_work);
+
+	wfx_tx_policy_upload(wvif);
+
+	wfx_tx_unlock(wvif->wdev);
+	wfx_tx_queues_unlock(wvif->wdev);
+}
+
+void wfx_tx_policy_init(struct wfx_vif *wvif)
+{
+	struct tx_policy_cache *cache = &wvif->tx_policy_cache;
+	int i;
+
+	memset(cache, 0, sizeof(*cache));
+
+	spin_lock_init(&cache->lock);
+	INIT_LIST_HEAD(&cache->used);
+	INIT_LIST_HEAD(&cache->free);
+	INIT_WORK(&wvif->tx_policy_upload_work, wfx_tx_policy_upload_work);
+
+	for (i = 0; i < HIF_MIB_NUM_TX_RATE_RETRY_POLICIES; ++i)
+		list_add(&cache->cache[i].link, &cache->free);
+}
+
+/* Link ID related functions */
+
+static int wfx_alloc_link_id(struct wfx_vif *wvif, const u8 *mac)
+{
+	int i, ret = 0;
+	unsigned long max_inactivity = 0;
+	unsigned long now = jiffies;
+
+	spin_lock_bh(&wvif->ps_state_lock);
+	for (i = 0; i < WFX_MAX_STA_IN_AP_MODE; ++i) {
+		if (!wvif->link_id_db[i].status) {
+			ret = i + 1;
+			break;
+		} else if (wvif->link_id_db[i].status != WFX_LINK_HARD &&
+			   !wvif->wdev->tx_queue_stats.link_map_cache[i + 1]) {
+			unsigned long inactivity =
+				now - wvif->link_id_db[i].timestamp;
+
+			if (inactivity < max_inactivity)
+				continue;
+			max_inactivity = inactivity;
+			ret = i + 1;
+		}
+	}
+
+	if (ret) {
+		struct wfx_link_entry *entry = &wvif->link_id_db[ret - 1];
+
+		entry->status = WFX_LINK_RESERVE;
+		ether_addr_copy(entry->mac, mac);
+		memset(&entry->buffered, 0, WFX_MAX_TID);
+		skb_queue_head_init(&entry->rx_queue);
+		wfx_tx_lock(wvif->wdev);
+
+		if (!schedule_work(&wvif->link_id_work))
+			wfx_tx_unlock(wvif->wdev);
+	} else {
+		dev_info(wvif->wdev->dev, "no more link-id available\n");
+	}
+	spin_unlock_bh(&wvif->ps_state_lock);
+	return ret;
+}
+
+int wfx_find_link_id(struct wfx_vif *wvif, const u8 *mac)
+{
+	int i, ret = 0;
+
+	spin_lock_bh(&wvif->ps_state_lock);
+	for (i = 0; i < WFX_MAX_STA_IN_AP_MODE; ++i) {
+		if (ether_addr_equal(mac, wvif->link_id_db[i].mac) &&
+		    wvif->link_id_db[i].status) {
+			wvif->link_id_db[i].timestamp = jiffies;
+			ret = i + 1;
+			break;
+		}
+	}
+	spin_unlock_bh(&wvif->ps_state_lock);
+	return ret;
+}
+
+static int wfx_map_link(struct wfx_vif *wvif,
+			struct wfx_link_entry *link_entry, int sta_id)
+{
+	int ret;
+
+	ret = hif_map_link(wvif, link_entry->mac, 0, sta_id);
+
+	if (ret == 0)
+		/* Save the MAC address currently associated with the peer
+		 * for future unmap request
+		 */
+		ether_addr_copy(link_entry->old_mac, link_entry->mac);
+
+	return ret;
+}
+
+int wfx_unmap_link(struct wfx_vif *wvif, int sta_id)
+{
+	u8 *mac_addr = NULL;
+
+	if (sta_id)
+		mac_addr = wvif->link_id_db[sta_id - 1].old_mac;
+
+	return hif_map_link(wvif, mac_addr, 1, sta_id);
+}
+
+void wfx_link_id_gc_work(struct work_struct *work)
+{
+	struct wfx_vif *wvif =
+		container_of(work, struct wfx_vif, link_id_gc_work.work);
+	unsigned long now = jiffies;
+	unsigned long next_gc = -1;
+	long ttl;
+	u32 mask;
+	int i;
+
+	if (wvif->state != WFX_STATE_AP)
+		return;
+
+	wfx_tx_lock_flush(wvif->wdev);
+	spin_lock_bh(&wvif->ps_state_lock);
+	for (i = 0; i < WFX_MAX_STA_IN_AP_MODE; ++i) {
+		bool need_reset = false;
+
+		mask = BIT(i + 1);
+		if (wvif->link_id_db[i].status == WFX_LINK_RESERVE ||
+		    (wvif->link_id_db[i].status == WFX_LINK_HARD &&
+		     !(wvif->link_id_map & mask))) {
+			if (wvif->link_id_map & mask) {
+				wvif->sta_asleep_mask &= ~mask;
+				wvif->pspoll_mask &= ~mask;
+				need_reset = true;
+			}
+			wvif->link_id_map |= mask;
+			if (wvif->link_id_db[i].status != WFX_LINK_HARD)
+				wvif->link_id_db[i].status = WFX_LINK_SOFT;
+
+			spin_unlock_bh(&wvif->ps_state_lock);
+			if (need_reset)
+				wfx_unmap_link(wvif, i + 1);
+			wfx_map_link(wvif, &wvif->link_id_db[i], i + 1);
+			next_gc = min(next_gc, WFX_LINK_ID_GC_TIMEOUT);
+			spin_lock_bh(&wvif->ps_state_lock);
+		} else if (wvif->link_id_db[i].status == WFX_LINK_SOFT) {
+			ttl = wvif->link_id_db[i].timestamp - now +
+					WFX_LINK_ID_GC_TIMEOUT;
+			if (ttl <= 0) {
+				need_reset = true;
+				wvif->link_id_db[i].status = WFX_LINK_OFF;
+				wvif->link_id_map &= ~mask;
+				wvif->sta_asleep_mask &= ~mask;
+				wvif->pspoll_mask &= ~mask;
+				spin_unlock_bh(&wvif->ps_state_lock);
+				wfx_unmap_link(wvif, i + 1);
+				spin_lock_bh(&wvif->ps_state_lock);
+			} else {
+				next_gc = min_t(unsigned long, next_gc, ttl);
+			}
+		}
+		if (need_reset)
+			skb_queue_purge(&wvif->link_id_db[i].rx_queue);
+	}
+	spin_unlock_bh(&wvif->ps_state_lock);
+	if (next_gc != -1)
+		schedule_delayed_work(&wvif->link_id_gc_work, next_gc);
+	wfx_tx_unlock(wvif->wdev);
+}
+
+void wfx_link_id_work(struct work_struct *work)
+{
+	struct wfx_vif *wvif =
+		container_of(work, struct wfx_vif, link_id_work);
+
+	wfx_tx_flush(wvif->wdev);
+	wfx_link_id_gc_work(&wvif->link_id_gc_work.work);
+	wfx_tx_unlock(wvif->wdev);
+}
+
+/* Tx implementation */
+
+static bool ieee80211_is_action_back(struct ieee80211_hdr *hdr)
+{
+	struct ieee80211_mgmt *mgmt = (struct ieee80211_mgmt *)hdr;
+
+	if (!ieee80211_is_action(mgmt->frame_control))
+		return false;
+	if (mgmt->u.action.category != WLAN_CATEGORY_BACK)
+		return false;
+	return true;
+}
+
+static void wfx_tx_manage_pm(struct wfx_vif *wvif, struct ieee80211_hdr *hdr,
+			     struct wfx_tx_priv *tx_priv,
+			     struct ieee80211_sta *sta)
+{
+	u32 mask = ~BIT(tx_priv->raw_link_id);
+
+	spin_lock_bh(&wvif->ps_state_lock);
+	if (ieee80211_is_auth(hdr->frame_control)) {
+		wvif->sta_asleep_mask &= mask;
+		wvif->pspoll_mask &= mask;
+	}
+
+	if (tx_priv->link_id == WFX_LINK_ID_AFTER_DTIM &&
+	    !wvif->mcast_buffered) {
+		wvif->mcast_buffered = true;
+		if (wvif->sta_asleep_mask)
+			schedule_work(&wvif->mcast_start_work);
+	}
+
+	if (tx_priv->raw_link_id) {
+		wvif->link_id_db[tx_priv->raw_link_id - 1].timestamp = jiffies;
+		if (tx_priv->tid < WFX_MAX_TID)
+			wvif->link_id_db[tx_priv->raw_link_id - 1].buffered[tx_priv->tid]++;
+	}
+	spin_unlock_bh(&wvif->ps_state_lock);
+
+	if (sta)
+		ieee80211_sta_set_buffered(sta, tx_priv->tid, true);
+}
+
+static u8 wfx_tx_get_raw_link_id(struct wfx_vif *wvif,
+				      struct ieee80211_sta *sta,
+				      struct ieee80211_hdr *hdr)
+{
+	struct wfx_sta_priv *sta_priv =
+		sta ? (struct wfx_sta_priv *) &sta->drv_priv : NULL;
+	const u8 *da = ieee80211_get_DA(hdr);
+	int ret;
+
+	if (sta_priv && sta_priv->link_id)
+		return sta_priv->link_id;
+	if (wvif->vif->type != NL80211_IFTYPE_AP)
+		return 0;
+	if (is_multicast_ether_addr(da))
+		return 0;
+	ret = wfx_find_link_id(wvif, da);
+	if (!ret)
+		ret = wfx_alloc_link_id(wvif, da);
+	if (!ret) {
+		dev_err(wvif->wdev->dev, "no more link-id available\n");
+		return WFX_LINK_ID_NO_ASSOC;
+	}
+	return ret;
+}
+
+static void wfx_tx_fixup_rates(struct ieee80211_tx_rate *rates)
+{
+	int i;
+	bool finished;
+
+	// Firmware is not able to mix rates with differents flags
+	for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
+		if (rates[0].flags & IEEE80211_TX_RC_SHORT_GI)
+			rates[i].flags |= IEEE80211_TX_RC_SHORT_GI;
+		if (!(rates[0].flags & IEEE80211_TX_RC_SHORT_GI))
+			rates[i].flags &= ~IEEE80211_TX_RC_SHORT_GI;
+		if (!(rates[0].flags & IEEE80211_TX_RC_USE_RTS_CTS))
+			rates[i].flags &= ~IEEE80211_TX_RC_USE_RTS_CTS;
+	}
+
+	// Sort rates and remove duplicates
+	do {
+		finished = true;
+		for (i = 0; i < IEEE80211_TX_MAX_RATES - 1; i++) {
+			if (rates[i + 1].idx == rates[i].idx &&
+			    rates[i].idx != -1) {
+				rates[i].count =
+					max_t(int, rates[i].count,
+					      rates[i + 1].count);
+				rates[i + 1].idx = -1;
+				rates[i + 1].count = 0;
+
+				finished = false;
+			}
+			if (rates[i + 1].idx > rates[i].idx) {
+				swap(rates[i + 1], rates[i]);
+				finished = false;
+			}
+		}
+	} while (!finished);
+	// All retries use long GI
+	for (i = 1; i < IEEE80211_TX_MAX_RATES; i++)
+		rates[i].flags &= ~IEEE80211_TX_RC_SHORT_GI;
+}
+
+static u8 wfx_tx_get_rate_id(struct wfx_vif *wvif,
+				  struct ieee80211_tx_info *tx_info)
+{
+	bool tx_policy_renew = false;
+	u8 rate_id;
+
+	rate_id = wfx_tx_policy_get(wvif,
+				    tx_info->driver_rates, &tx_policy_renew);
+	WARN(rate_id == WFX_INVALID_RATE_ID, "unable to get a valid Tx policy");
+
+	if (tx_policy_renew) {
+		/* FIXME: It's not so optimal to stop TX queues every now and
+		 * then.  Better to reimplement task scheduling with a counter.
+		 */
+		wfx_tx_lock(wvif->wdev);
+		wfx_tx_queues_lock(wvif->wdev);
+		if (!schedule_work(&wvif->tx_policy_upload_work)) {
+			wfx_tx_queues_unlock(wvif->wdev);
+			wfx_tx_unlock(wvif->wdev);
+		}
+	}
+	return rate_id;
+}
+
+static struct hif_ht_tx_parameters wfx_tx_get_tx_parms(struct wfx_dev *wdev, struct ieee80211_tx_info *tx_info)
+{
+	struct ieee80211_tx_rate *rate = &tx_info->driver_rates[0];
+	struct hif_ht_tx_parameters ret = { };
+
+	if (!(rate->flags & IEEE80211_TX_RC_MCS))
+		ret.frame_format = HIF_FRAME_FORMAT_NON_HT;
+	else if (!(rate->flags & IEEE80211_TX_RC_GREEN_FIELD))
+		ret.frame_format = HIF_FRAME_FORMAT_MIXED_FORMAT_HT;
+	else
+		ret.frame_format = HIF_FRAME_FORMAT_GF_HT_11N;
+	if (rate->flags & IEEE80211_TX_RC_SHORT_GI)
+		ret.short_gi = 1;
+	if (tx_info->flags & IEEE80211_TX_CTL_STBC)
+		ret.stbc = 0; // FIXME: Not yet supported by firmware?
+	return ret;
+}
+
+static u8 wfx_tx_get_tid(struct ieee80211_hdr *hdr)
+{
+	// FIXME: ieee80211_get_tid(hdr) should be sufficient for all cases.
+	if (!ieee80211_is_data(hdr->frame_control))
+		return WFX_MAX_TID;
+	if (ieee80211_is_data_qos(hdr->frame_control))
+		return ieee80211_get_tid(hdr);
+	else
+		return 0;
+}
+
+static int wfx_tx_get_icv_len(struct ieee80211_key_conf *hw_key)
+{
+	int mic_space;
+
+	if (!hw_key)
+		return 0;
+	mic_space = (hw_key->cipher == WLAN_CIPHER_SUITE_TKIP) ? 8 : 0;
+	return hw_key->icv_len + mic_space;
+}
+
+static int wfx_tx_inner(struct wfx_vif *wvif, struct ieee80211_sta *sta,
+			struct sk_buff *skb)
+{
+	struct hif_msg *hif_msg;
+	struct hif_req_tx *req;
+	struct wfx_tx_priv *tx_priv;
+	struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(skb);
+	struct ieee80211_key_conf *hw_key = tx_info->control.hw_key;
+	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
+	int queue_id = tx_info->hw_queue;
+	size_t offset = (size_t) skb->data & 3;
+	int wmsg_len = sizeof(struct hif_msg) +
+			sizeof(struct hif_req_tx) + offset;
+
+	WARN(queue_id >= IEEE80211_NUM_ACS, "unsupported queue_id");
+	wfx_tx_fixup_rates(tx_info->driver_rates);
+
+	// From now tx_info->control is unusable
+	memset(tx_info->rate_driver_data, 0, sizeof(struct wfx_tx_priv));
+	// Fill tx_priv
+	tx_priv = (struct wfx_tx_priv *)tx_info->rate_driver_data;
+	tx_priv->tid = wfx_tx_get_tid(hdr);
+	tx_priv->raw_link_id = wfx_tx_get_raw_link_id(wvif, sta, hdr);
+	tx_priv->link_id = tx_priv->raw_link_id;
+	if (ieee80211_has_protected(hdr->frame_control))
+		tx_priv->hw_key = hw_key;
+	if (tx_info->flags & IEEE80211_TX_CTL_SEND_AFTER_DTIM)
+		tx_priv->link_id = WFX_LINK_ID_AFTER_DTIM;
+	if (sta && (sta->uapsd_queues & BIT(queue_id)))
+		tx_priv->link_id = WFX_LINK_ID_UAPSD;
+
+	// Fill hif_msg
+	WARN(skb_headroom(skb) < wmsg_len, "not enough space in skb");
+	WARN(offset & 1, "attempt to transmit an unaligned frame");
+	skb_put(skb, wfx_tx_get_icv_len(tx_priv->hw_key));
+	skb_push(skb, wmsg_len);
+	memset(skb->data, 0, wmsg_len);
+	hif_msg = (struct hif_msg *)skb->data;
+	hif_msg->len = cpu_to_le16(skb->len);
+	hif_msg->id = HIF_REQ_ID_TX;
+	hif_msg->interface = wvif->id;
+	if (skb->len > wvif->wdev->hw_caps.size_inp_ch_buf) {
+		dev_warn(wvif->wdev->dev, "requested frame size (%d) is larger than maximum supported (%d)\n",
+			 skb->len, wvif->wdev->hw_caps.size_inp_ch_buf);
+		skb_pull(skb, wmsg_len);
+		return -EIO;
+	}
+
+	// Fill tx request
+	req = (struct hif_req_tx *)hif_msg->body;
+	req->packet_id = queue_id << 16 |
+			 IEEE80211_SEQ_TO_SN(le16_to_cpu(hdr->seq_ctrl));
+	req->data_flags.fc_offset = offset;
+	req->queue_id.peer_sta_id = tx_priv->raw_link_id;
+	// Queue index are inverted between firmware and Linux
+	req->queue_id.queue_id = 3 - queue_id;
+	req->ht_tx_parameters = wfx_tx_get_tx_parms(wvif->wdev, tx_info);
+	req->tx_flags.retry_policy_index = wfx_tx_get_rate_id(wvif, tx_info);
+
+	// Auxiliary operations
+	wfx_tx_manage_pm(wvif, hdr, tx_priv, sta);
+	wfx_tx_queue_put(wvif->wdev, &wvif->wdev->tx_queue[queue_id], skb);
+	wfx_bh_request_tx(wvif->wdev);
+	return 0;
+}
+
+void wfx_tx(struct ieee80211_hw *hw, struct ieee80211_tx_control *control,
+	    struct sk_buff *skb)
+{
+	struct wfx_dev *wdev = hw->priv;
+	struct wfx_vif *wvif;
+	struct ieee80211_sta *sta = control ? control->sta : NULL;
+	struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(skb);
+	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
+	size_t driver_data_room = FIELD_SIZEOF(struct ieee80211_tx_info,
+					       rate_driver_data);
+
+	compiletime_assert(sizeof(struct wfx_tx_priv) <= driver_data_room,
+			   "struct tx_priv is too large");
+	WARN(skb->next || skb->prev, "skb is already member of a list");
+	// control.vif can be NULL for injected frames
+	if (tx_info->control.vif)
+		wvif = (struct wfx_vif *)tx_info->control.vif->drv_priv;
+	else
+		wvif = wvif_iterate(wdev, NULL);
+	if (WARN_ON(!wvif))
+		goto drop;
+	// FIXME: why?
+	if (ieee80211_is_action_back(hdr)) {
+		dev_info(wdev->dev, "drop BA action\n");
+		goto drop;
+	}
+	if (wfx_tx_inner(wvif, sta, skb))
+		goto drop;
+
+	return;
+
+drop:
+	ieee80211_tx_status_irqsafe(wdev->hw, skb);
+}
+
+void wfx_tx_confirm_cb(struct wfx_vif *wvif, struct hif_cnf_tx *arg)
+{
+	int i;
+	int tx_count;
+	struct sk_buff *skb;
+	struct ieee80211_tx_rate *rate;
+	struct ieee80211_tx_info *tx_info;
+	const struct wfx_tx_priv *tx_priv;
+
+	skb = wfx_pending_get(wvif->wdev, arg->packet_id);
+	if (!skb) {
+		dev_warn(wvif->wdev->dev,
+			 "received unknown packet_id (%#.8x) from chip\n",
+			 arg->packet_id);
+		return;
+	}
+	tx_info = IEEE80211_SKB_CB(skb);
+	tx_priv = wfx_skb_tx_priv(skb);
+	_trace_tx_stats(arg, skb,
+			wfx_pending_get_pkt_us_delay(wvif->wdev, skb));
+
+	// You can touch to tx_priv, but don't touch to tx_info->status.
+	tx_count = arg->ack_failures;
+	if (!arg->status || arg->ack_failures)
+		tx_count += 1; // Also report success
+	for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
+		rate = &tx_info->status.rates[i];
+		if (rate->idx < 0)
+			break;
+		if (tx_count < rate->count && arg->status && arg->ack_failures)
+			dev_dbg(wvif->wdev->dev, "all retries were not consumed: %d != %d\n",
+				rate->count, tx_count);
+		if (tx_count <= rate->count && tx_count &&
+		    arg->txed_rate != wfx_get_hw_rate(wvif->wdev, rate))
+			dev_dbg(wvif->wdev->dev,
+				"inconsistent tx_info rates: %d != %d\n",
+				arg->txed_rate,
+				wfx_get_hw_rate(wvif->wdev, rate));
+		if (tx_count > rate->count) {
+			tx_count -= rate->count;
+		} else if (!tx_count) {
+			rate->count = 0;
+			rate->idx = -1;
+		} else {
+			rate->count = tx_count;
+			tx_count = 0;
+		}
+	}
+	if (tx_count)
+		dev_dbg(wvif->wdev->dev,
+			"%d more retries than expected\n", tx_count);
+	skb_trim(skb, skb->len - wfx_tx_get_icv_len(tx_priv->hw_key));
+
+	// From now, you can touch to tx_info->status, but do not touch to
+	// tx_priv anymore
+	// FIXME: use ieee80211_tx_info_clear_status()
+	memset(tx_info->rate_driver_data, 0, sizeof(tx_info->rate_driver_data));
+	memset(tx_info->pad, 0, sizeof(tx_info->pad));
+
+	if (!arg->status) {
+		if (wvif->bss_loss_state &&
+		    arg->packet_id == wvif->bss_loss_confirm_id)
+			wfx_cqm_bssloss_sm(wvif, 0, 1, 0);
+		tx_info->status.tx_time =
+		arg->media_delay - arg->tx_queue_delay;
+		if (tx_info->flags & IEEE80211_TX_CTL_NO_ACK)
+			tx_info->flags |= IEEE80211_TX_STAT_NOACK_TRANSMITTED;
+		else
+			tx_info->flags |= IEEE80211_TX_STAT_ACK;
+	} else if (arg->status == HIF_REQUEUE) {
+		/* "REQUEUE" means "implicit suspend" */
+		struct hif_ind_suspend_resume_tx suspend = {
+			.suspend_resume_flags.resume = 0,
+			.suspend_resume_flags.bc_mc_only = 1,
+		};
+
+		WARN(!arg->tx_result_flags.requeue, "incoherent status and result_flags");
+		wfx_suspend_resume(wvif, &suspend);
+		tx_info->flags |= IEEE80211_TX_STAT_TX_FILTERED;
+	} else {
+		if (wvif->bss_loss_state &&
+		    arg->packet_id == wvif->bss_loss_confirm_id)
+			wfx_cqm_bssloss_sm(wvif, 0, 0, 1);
+	}
+	wfx_pending_remove(wvif->wdev, skb);
+}
+
+static void wfx_notify_buffered_tx(struct wfx_vif *wvif, struct sk_buff *skb,
+				   struct hif_req_tx *req)
+{
+	struct ieee80211_sta *sta;
+	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
+	int tid = wfx_tx_get_tid(hdr);
+	int raw_link_id = req->queue_id.peer_sta_id;
+	u8 *buffered;
+
+	if (raw_link_id && tid < WFX_MAX_TID) {
+		buffered = wvif->link_id_db[raw_link_id - 1].buffered;
+
+		spin_lock_bh(&wvif->ps_state_lock);
+		WARN(!buffered[tid], "inconsistent notification");
+		buffered[tid]--;
+		spin_unlock_bh(&wvif->ps_state_lock);
+
+		if (!buffered[tid]) {
+			rcu_read_lock();
+			sta = ieee80211_find_sta(wvif->vif, hdr->addr1);
+			if (sta)
+				ieee80211_sta_set_buffered(sta, tid, false);
+			rcu_read_unlock();
+		}
+	}
+}
+
+void wfx_skb_dtor(struct wfx_dev *wdev, struct sk_buff *skb)
+{
+	struct hif_msg *hif = (struct hif_msg *)skb->data;
+	struct hif_req_tx *req = (struct hif_req_tx *)hif->body;
+	struct wfx_vif *wvif = wdev_to_wvif(wdev, hif->interface);
+	unsigned int offset = sizeof(struct hif_req_tx) +
+				sizeof(struct hif_msg) +
+				req->data_flags.fc_offset;
+
+	WARN_ON(!wvif);
+	skb_pull(skb, offset);
+	wfx_notify_buffered_tx(wvif, skb, req);
+	wfx_tx_policy_put(wvif, req->tx_flags.retry_policy_index);
+	ieee80211_tx_status_irqsafe(wdev->hw, skb);
+}