// SPDX-License-Identifier: GPL-2.0-only
/*
 * Queue between the tx operation and the bh workqueue.
 *
 * Copyright (c) 2017-2020, Silicon Laboratories, Inc.
 * Copyright (c) 2010, ST-Ericsson
 */
#include <linux/sched.h>
#include <net/mac80211.h>

#include "queue.h"
#include "wfx.h"
#include "sta.h"
#include "data_tx.h"
#include "traces.h"

void wfx_tx_lock(struct wfx_dev *wdev)
{
        atomic_inc(&wdev->tx_lock);
}

void wfx_tx_unlock(struct wfx_dev *wdev)
{
        int tx_lock = atomic_dec_return(&wdev->tx_lock);

        WARN(tx_lock < 0, "inconsistent tx_lock value");
        if (!tx_lock)
                wfx_bh_request_tx(wdev);
}

void wfx_tx_flush(struct wfx_dev *wdev)
{
        int ret;

        /* Do not wait for any reply if chip is frozen */
        if (wdev->chip_frozen)
                return;

        wfx_tx_lock(wdev);
        mutex_lock(&wdev->hif_cmd.lock);
        ret = wait_event_timeout(wdev->hif.tx_buffers_empty, !wdev->hif.tx_buffers_used,
                                 msecs_to_jiffies(3000));
        if (!ret) {
                dev_warn(wdev->dev, "cannot flush tx buffers (%d still busy)\n",
                         wdev->hif.tx_buffers_used);
                wfx_pending_dump_old_frames(wdev, 3000);
                /* FIXME: drop pending frames here */
                wdev->chip_frozen = true;
        }
        mutex_unlock(&wdev->hif_cmd.lock);
        wfx_tx_unlock(wdev);
}

void wfx_tx_lock_flush(struct wfx_dev *wdev)
{
        wfx_tx_lock(wdev);
        wfx_tx_flush(wdev);
}

void wfx_tx_queues_init(struct wfx_vif *wvif)
{
        /* The device is in charge to respect the details of the QoS parameters. The driver just
         * ensure that it roughtly respect the priorities to avoid any shortage.
         */
        const int priorities[IEEE80211_NUM_ACS] = { 1, 2, 64, 128 };
        int i;

        for (i = 0; i < IEEE80211_NUM_ACS; ++i) {
                skb_queue_head_init(&wvif->tx_queue[i].normal);
                skb_queue_head_init(&wvif->tx_queue[i].cab);
                skb_queue_head_init(&wvif->tx_queue[i].offchan);
                wvif->tx_queue[i].priority = priorities[i];
        }
}

bool wfx_tx_queue_empty(struct wfx_vif *wvif, struct wfx_queue *queue)
{
        return skb_queue_empty_lockless(&queue->normal) &&
               skb_queue_empty_lockless(&queue->cab) &&
               skb_queue_empty_lockless(&queue->offchan);
}

void wfx_tx_queues_check_empty(struct wfx_vif *wvif)
{
        int i;

        for (i = 0; i < IEEE80211_NUM_ACS; ++i) {
                WARN_ON(atomic_read(&wvif->tx_queue[i].pending_frames));
                WARN_ON(!wfx_tx_queue_empty(wvif, &wvif->tx_queue[i]));
        }
}

static void __wfx_tx_queue_drop(struct wfx_vif *wvif,
                                struct sk_buff_head *skb_queue, struct sk_buff_head *dropped)
{
        struct sk_buff *skb, *tmp;

        spin_lock_bh(&skb_queue->lock);
        skb_queue_walk_safe(skb_queue, skb, tmp) {
                __skb_unlink(skb, skb_queue);
                skb_queue_head(dropped, skb);
        }
        spin_unlock_bh(&skb_queue->lock);
}

void wfx_tx_queue_drop(struct wfx_vif *wvif, struct wfx_queue *queue,
                       struct sk_buff_head *dropped)
{
        __wfx_tx_queue_drop(wvif, &queue->normal, dropped);
        __wfx_tx_queue_drop(wvif, &queue->cab, dropped);
        __wfx_tx_queue_drop(wvif, &queue->offchan, dropped);
        wake_up(&wvif->wdev->tx_dequeue);
}

void wfx_tx_queues_put(struct wfx_vif *wvif, struct sk_buff *skb)
{
        struct wfx_queue *queue = &wvif->tx_queue[skb_get_queue_mapping(skb)];
        struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(skb);

        if (tx_info->flags & IEEE80211_TX_CTL_TX_OFFCHAN)
                skb_queue_tail(&queue->offchan, skb);
        else if (tx_info->flags & IEEE80211_TX_CTL_SEND_AFTER_DTIM)
                skb_queue_tail(&queue->cab, skb);
        else
                skb_queue_tail(&queue->normal, skb);
}

void wfx_pending_drop(struct wfx_dev *wdev, struct sk_buff_head *dropped)
{
        struct wfx_queue *queue;
        struct wfx_vif *wvif;
        struct sk_buff *skb;

        WARN(!wdev->chip_frozen, "%s should only be used to recover a frozen device", __func__);
        while ((skb = skb_dequeue(&wdev->tx_pending)) != NULL) {
                wvif = wfx_skb_wvif(wdev, skb);
                if (wvif) {
                        queue = &wvif->tx_queue[skb_get_queue_mapping(skb)];
                        WARN_ON(skb_get_queue_mapping(skb) > 3);
                        WARN_ON(!atomic_read(&queue->pending_frames));
                        atomic_dec(&queue->pending_frames);
                }
                skb_queue_head(dropped, skb);
        }
}

struct sk_buff *wfx_pending_get(struct wfx_dev *wdev, u32 packet_id)
{
        struct wfx_queue *queue;
        struct wfx_hif_req_tx *req;
        struct wfx_vif *wvif;
        struct wfx_hif_msg *hif;
        struct sk_buff *skb;

        spin_lock_bh(&wdev->tx_pending.lock);
        skb_queue_walk(&wdev->tx_pending, skb) {
                hif = (struct wfx_hif_msg *)skb->data;
                req = (struct wfx_hif_req_tx *)hif->body;
                if (req->packet_id != packet_id)
                        continue;
                spin_unlock_bh(&wdev->tx_pending.lock);
                wvif = wfx_skb_wvif(wdev, skb);
                if (wvif) {
                        queue = &wvif->tx_queue[skb_get_queue_mapping(skb)];
                        WARN_ON(skb_get_queue_mapping(skb) > 3);
                        WARN_ON(!atomic_read(&queue->pending_frames));
                        atomic_dec(&queue->pending_frames);
                }
                skb_unlink(skb, &wdev->tx_pending);
                return skb;
        }
        spin_unlock_bh(&wdev->tx_pending.lock);
        WARN(1, "cannot find packet in pending queue");
        return NULL;
}

void wfx_pending_dump_old_frames(struct wfx_dev *wdev, unsigned int limit_ms)
{
        ktime_t now = ktime_get();
        struct wfx_tx_priv *tx_priv;
        struct wfx_hif_req_tx *req;
        struct sk_buff *skb;
        bool first = true;

        spin_lock_bh(&wdev->tx_pending.lock);
        skb_queue_walk(&wdev->tx_pending, skb) {
                tx_priv = wfx_skb_tx_priv(skb);
                req = wfx_skb_txreq(skb);
                if (ktime_after(now, ktime_add_ms(tx_priv->xmit_timestamp, limit_ms))) {
                        if (first) {
                                dev_info(wdev->dev, "frames stuck in firmware since %dms or more:\n",
                                         limit_ms);
                                first = false;
                        }
                        dev_info(wdev->dev, "   id %08x sent %lldms ago\n",
                                 req->packet_id, ktime_ms_delta(now, tx_priv->xmit_timestamp));
                }
        }
        spin_unlock_bh(&wdev->tx_pending.lock);
}

unsigned int wfx_pending_get_pkt_us_delay(struct wfx_dev *wdev, struct sk_buff *skb)
{
        ktime_t now = ktime_get();
        struct wfx_tx_priv *tx_priv = wfx_skb_tx_priv(skb);

        return ktime_us_delta(now, tx_priv->xmit_timestamp);
}

bool wfx_tx_queues_has_cab(struct wfx_vif *wvif)
{
        struct ieee80211_vif *vif = wvif_to_vif(wvif);
        int i;

        if (vif->type != NL80211_IFTYPE_AP)
                return false;
        for (i = 0; i < IEEE80211_NUM_ACS; ++i)
                /* Note: since only AP can have mcast frames in queue and only one vif can be AP,
                 * all queued frames has same interface id
                 */
                if (!skb_queue_empty_lockless(&wvif->tx_queue[i].cab))
                        return true;
        return false;
}

static int wfx_tx_queue_get_weight(struct wfx_queue *queue)
{
        return atomic_read(&queue->pending_frames) * queue->priority;
}

static struct sk_buff *wfx_tx_queues_get_skb(struct wfx_dev *wdev)
{
        struct wfx_queue *queues[IEEE80211_NUM_ACS * ARRAY_SIZE(wdev->vif)];
        int i, j, num_queues = 0;
        struct wfx_vif *wvif;
        struct wfx_hif_msg *hif;
        struct sk_buff *skb;

        /* sort the queues */
        wvif = NULL;
        while ((wvif = wvif_iterate(wdev, wvif)) != NULL) {
                for (i = 0; i < IEEE80211_NUM_ACS; i++) {
                        WARN_ON(num_queues >= ARRAY_SIZE(queues));
                        queues[num_queues] = &wvif->tx_queue[i];
                        for (j = num_queues; j > 0; j--)
                                if (wfx_tx_queue_get_weight(queues[j]) <
                                    wfx_tx_queue_get_weight(queues[j - 1]))
                                        swap(queues[j - 1], queues[j]);
                        num_queues++;
                }
        }

        wvif = NULL;
        while ((wvif = wvif_iterate(wdev, wvif)) != NULL) {
                for (i = 0; i < num_queues; i++) {
                        skb = skb_dequeue(&queues[i]->offchan);
                        if (!skb)
                                continue;
                        hif = (struct wfx_hif_msg *)skb->data;
                        /* Offchan frames are assigned to a special interface.
                         * The only interface allowed to send data during scan.
                         */
                        WARN_ON(hif->interface != 2);
                        atomic_inc(&queues[i]->pending_frames);
                        trace_queues_stats(wdev, queues[i]);
                        return skb;
                }
        }

        if (mutex_is_locked(&wdev->scan_lock))
                return NULL;

        wvif = NULL;
        while ((wvif = wvif_iterate(wdev, wvif)) != NULL) {
                if (!wvif->after_dtim_tx_allowed)
                        continue;
                for (i = 0; i < num_queues; i++) {
                        skb = skb_dequeue(&queues[i]->cab);
                        if (!skb)
                                continue;
                        /* Note: since only AP can have mcast frames in queue and only one vif can
                         * be AP, all queued frames has same interface id
                         */
                        hif = (struct wfx_hif_msg *)skb->data;
                        WARN_ON(hif->interface != wvif->id);
                        WARN_ON(queues[i] != &wvif->tx_queue[skb_get_queue_mapping(skb)]);
                        atomic_inc(&queues[i]->pending_frames);
                        trace_queues_stats(wdev, queues[i]);
                        return skb;
                }
                /* No more multicast to sent */
                wvif->after_dtim_tx_allowed = false;
                schedule_work(&wvif->update_tim_work);
        }

        for (i = 0; i < num_queues; i++) {
                skb = skb_dequeue(&queues[i]->normal);
                if (skb) {
                        atomic_inc(&queues[i]->pending_frames);
                        trace_queues_stats(wdev, queues[i]);
                        return skb;
                }
        }
        return NULL;
}

struct wfx_hif_msg *wfx_tx_queues_get(struct wfx_dev *wdev)
{
        struct wfx_tx_priv *tx_priv;
        struct sk_buff *skb;

        if (atomic_read(&wdev->tx_lock))
                return NULL;
        skb = wfx_tx_queues_get_skb(wdev);
        if (!skb)
                return NULL;
        skb_queue_tail(&wdev->tx_pending, skb);
        wake_up(&wdev->tx_dequeue);
        tx_priv = wfx_skb_tx_priv(skb);
        tx_priv->xmit_timestamp = ktime_get();
        return (struct wfx_hif_msg *)skb->data;
}