/*
 * Copyright (c) 2005-2011 Atheros Communications Inc.
 * Copyright (c) 2011-2013 Qualcomm Atheros, Inc.
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include "core.h"
#include "htc.h"
#include "htt.h"
#include "txrx.h"
#include "debug.h"
#include "trace.h"
#include "mac.h"

#include <linux/log2.h>

#define HTT_RX_RING_SIZE HTT_RX_RING_SIZE_MAX
#define HTT_RX_RING_FILL_LEVEL (((HTT_RX_RING_SIZE) / 2) - 1)

/* when under memory pressure rx ring refill may fail and needs a retry */
#define HTT_RX_RING_REFILL_RETRY_MS 50

#define HTT_RX_RING_REFILL_RESCHED_MS 5

static int ath10k_htt_rx_get_csum_state(struct sk_buff *skb);
static void ath10k_htt_txrx_compl_task(unsigned long ptr);

static struct sk_buff *
ath10k_htt_rx_find_skb_paddr(struct ath10k *ar, u32 paddr)
{
        struct ath10k_skb_rxcb *rxcb;

        hash_for_each_possible(ar->htt.rx_ring.skb_table, rxcb, hlist, paddr)
                if (rxcb->paddr == paddr)
                        return ATH10K_RXCB_SKB(rxcb);

        WARN_ON_ONCE(1);
        return NULL;
}

static void ath10k_htt_rx_ring_free(struct ath10k_htt *htt)
{
        struct sk_buff *skb;
        struct ath10k_skb_rxcb *rxcb;
        struct hlist_node *n;
        int i;

        if (htt->rx_ring.in_ord_rx) {
                hash_for_each_safe(htt->rx_ring.skb_table, i, n, rxcb, hlist) {
                        skb = ATH10K_RXCB_SKB(rxcb);
                        dma_unmap_single(htt->ar->dev, rxcb->paddr,
                                         skb->len + skb_tailroom(skb),
                                         DMA_FROM_DEVICE);
                        hash_del(&rxcb->hlist);
                        dev_kfree_skb_any(skb);
                }
        } else {
                for (i = 0; i < htt->rx_ring.size; i++) {
                        skb = htt->rx_ring.netbufs_ring[i];
                        if (!skb)
                                continue;

                        rxcb = ATH10K_SKB_RXCB(skb);
                        dma_unmap_single(htt->ar->dev, rxcb->paddr,
                                         skb->len + skb_tailroom(skb),
                                         DMA_FROM_DEVICE);
                        dev_kfree_skb_any(skb);
                }
        }

        htt->rx_ring.fill_cnt = 0;
        hash_init(htt->rx_ring.skb_table);
        memset(htt->rx_ring.netbufs_ring, 0,
               htt->rx_ring.size * sizeof(htt->rx_ring.netbufs_ring[0]));
}

static int __ath10k_htt_rx_ring_fill_n(struct ath10k_htt *htt, int num)
{
        struct htt_rx_desc *rx_desc;
        struct ath10k_skb_rxcb *rxcb;
        struct sk_buff *skb;
        dma_addr_t paddr;
        int ret = 0, idx;

        /* The Full Rx Reorder firmware has no way of telling the host
         * implicitly when it copied HTT Rx Ring buffers to MAC Rx Ring.
         * To keep things simple make sure ring is always half empty. This
         * guarantees there'll be no replenishment overruns possible.
         */
        BUILD_BUG_ON(HTT_RX_RING_FILL_LEVEL >= HTT_RX_RING_SIZE / 2);

        idx = __le32_to_cpu(*htt->rx_ring.alloc_idx.vaddr);
        while (num > 0) {
                skb = dev_alloc_skb(HTT_RX_BUF_SIZE + HTT_RX_DESC_ALIGN);
                if (!skb) {
                        ret = -ENOMEM;
                        goto fail;
                }

                if (!IS_ALIGNED((unsigned long)skb->data, HTT_RX_DESC_ALIGN))
                        skb_pull(skb,
                                 PTR_ALIGN(skb->data, HTT_RX_DESC_ALIGN) -
                                 skb->data);

                /* Clear rx_desc attention word before posting to Rx ring */
                rx_desc = (struct htt_rx_desc *)skb->data;
                rx_desc->attention.flags = __cpu_to_le32(0);

                paddr = dma_map_single(htt->ar->dev, skb->data,
                                       skb->len + skb_tailroom(skb),
                                       DMA_FROM_DEVICE);

                if (unlikely(dma_mapping_error(htt->ar->dev, paddr))) {
                        dev_kfree_skb_any(skb);
                        ret = -ENOMEM;
                        goto fail;
                }

                rxcb = ATH10K_SKB_RXCB(skb);
                rxcb->paddr = paddr;
                htt->rx_ring.netbufs_ring[idx] = skb;
                htt->rx_ring.paddrs_ring[idx] = __cpu_to_le32(paddr);
                htt->rx_ring.fill_cnt++;

                if (htt->rx_ring.in_ord_rx) {
                        hash_add(htt->rx_ring.skb_table,
                                 &ATH10K_SKB_RXCB(skb)->hlist,
                                 (u32)paddr);
                }

                num--;
                idx++;
                idx &= htt->rx_ring.size_mask;
        }

fail:
        /*
         * Make sure the rx buffer is updated before available buffer
         * index to avoid any potential rx ring corruption.
         */
        mb();
        *htt->rx_ring.alloc_idx.vaddr = __cpu_to_le32(idx);
        return ret;
}

static int ath10k_htt_rx_ring_fill_n(struct ath10k_htt *htt, int num)
{
        lockdep_assert_held(&htt->rx_ring.lock);
        return __ath10k_htt_rx_ring_fill_n(htt, num);
}

static void ath10k_htt_rx_msdu_buff_replenish(struct ath10k_htt *htt)
{
        int ret, num_deficit, num_to_fill;

        /* Refilling the whole RX ring buffer proves to be a bad idea. The
         * reason is RX may take up significant amount of CPU cycles and starve
         * other tasks, e.g. TX on an ethernet device while acting as a bridge
         * with ath10k wlan interface. This ended up with very poor performance
         * once CPU the host system was overwhelmed with RX on ath10k.
         *
         * By limiting the number of refills the replenishing occurs
         * progressively. This in turns makes use of the fact tasklets are
         * processed in FIFO order. This means actual RX processing can starve
         * out refilling. If there's not enough buffers on RX ring FW will not
         * report RX until it is refilled with enough buffers. This
         * automatically balances load wrt to CPU power.
         *
         * This probably comes at a cost of lower maximum throughput but
         * improves the average and stability. */
        spin_lock_bh(&htt->rx_ring.lock);
        num_deficit = htt->rx_ring.fill_level - htt->rx_ring.fill_cnt;
        num_to_fill = min(ATH10K_HTT_MAX_NUM_REFILL, num_deficit);
        num_deficit -= num_to_fill;
        ret = ath10k_htt_rx_ring_fill_n(htt, num_to_fill);
        if (ret == -ENOMEM) {
                /*
                 * Failed to fill it to the desired level -
                 * we'll start a timer and try again next time.
                 * As long as enough buffers are left in the ring for
                 * another A-MPDU rx, no special recovery is needed.
                 */
                mod_timer(&htt->rx_ring.refill_retry_timer, jiffies +
                          msecs_to_jiffies(HTT_RX_RING_REFILL_RETRY_MS));
        } else if (num_deficit > 0) {
                mod_timer(&htt->rx_ring.refill_retry_timer, jiffies +
                          msecs_to_jiffies(HTT_RX_RING_REFILL_RESCHED_MS));
        }
        spin_unlock_bh(&htt->rx_ring.lock);
}

static void ath10k_htt_rx_ring_refill_retry(unsigned long arg)
{
        struct ath10k_htt *htt = (struct ath10k_htt *)arg;

        ath10k_htt_rx_msdu_buff_replenish(htt);
}

int ath10k_htt_rx_ring_refill(struct ath10k *ar)
{
        struct ath10k_htt *htt = &ar->htt;
        int ret;

        spin_lock_bh(&htt->rx_ring.lock);
        ret = ath10k_htt_rx_ring_fill_n(htt, (htt->rx_ring.fill_level -
                                              htt->rx_ring.fill_cnt));
        spin_unlock_bh(&htt->rx_ring.lock);

        if (ret)
                ath10k_htt_rx_ring_free(htt);

        return ret;
}

void ath10k_htt_rx_free(struct ath10k_htt *htt)
{
        del_timer_sync(&htt->rx_ring.refill_retry_timer);
        tasklet_kill(&htt->txrx_compl_task);

        skb_queue_purge(&htt->rx_compl_q);
        skb_queue_purge(&htt->rx_in_ord_compl_q);
        skb_queue_purge(&htt->tx_fetch_ind_q);

        ath10k_htt_rx_ring_free(htt);

        dma_free_coherent(htt->ar->dev,
                          (htt->rx_ring.size *
                           sizeof(htt->rx_ring.paddrs_ring)),
                          htt->rx_ring.paddrs_ring,
                          htt->rx_ring.base_paddr);

        dma_free_coherent(htt->ar->dev,
                          sizeof(*htt->rx_ring.alloc_idx.vaddr),
                          htt->rx_ring.alloc_idx.vaddr,
                          htt->rx_ring.alloc_idx.paddr);

        kfree(htt->rx_ring.netbufs_ring);
}

static inline struct sk_buff *ath10k_htt_rx_netbuf_pop(struct ath10k_htt *htt)
{
        struct ath10k *ar = htt->ar;
        int idx;
        struct sk_buff *msdu;

        lockdep_assert_held(&htt->rx_ring.lock);

        if (htt->rx_ring.fill_cnt == 0) {
                ath10k_warn(ar, "tried to pop sk_buff from an empty rx ring\n");
                return NULL;
        }

        idx = htt->rx_ring.sw_rd_idx.msdu_payld;
        msdu = htt->rx_ring.netbufs_ring[idx];
        htt->rx_ring.netbufs_ring[idx] = NULL;
        htt->rx_ring.paddrs_ring[idx] = 0;

        idx++;
        idx &= htt->rx_ring.size_mask;
        htt->rx_ring.sw_rd_idx.msdu_payld = idx;
        htt->rx_ring.fill_cnt--;

        dma_unmap_single(htt->ar->dev,
                         ATH10K_SKB_RXCB(msdu)->paddr,
                         msdu->len + skb_tailroom(msdu),
                         DMA_FROM_DEVICE);
        ath10k_dbg_dump(ar, ATH10K_DBG_HTT_DUMP, NULL, "htt rx netbuf pop: ",
                        msdu->data, msdu->len + skb_tailroom(msdu));

        return msdu;
}

/* return: < 0 fatal error, 0 - non chained msdu, 1 chained msdu */
static int ath10k_htt_rx_amsdu_pop(struct ath10k_htt *htt,
                                   struct sk_buff_head *amsdu)
{
        struct ath10k *ar = htt->ar;
        int msdu_len, msdu_chaining = 0;
        struct sk_buff *msdu;
        struct htt_rx_desc *rx_desc;

        lockdep_assert_held(&htt->rx_ring.lock);

        for (;;) {
                int last_msdu, msdu_len_invalid, msdu_chained;

                msdu = ath10k_htt_rx_netbuf_pop(htt);
                if (!msdu) {
                        __skb_queue_purge(amsdu);
                        return -ENOENT;
                }

                __skb_queue_tail(amsdu, msdu);

                rx_desc = (struct htt_rx_desc *)msdu->data;

                /* FIXME: we must report msdu payload since this is what caller
                 *        expects now */
                skb_put(msdu, offsetof(struct htt_rx_desc, msdu_payload));
                skb_pull(msdu, offsetof(struct htt_rx_desc, msdu_payload));

                /*
                 * Sanity check - confirm the HW is finished filling in the
                 * rx data.
                 * If the HW and SW are working correctly, then it's guaranteed
                 * that the HW's MAC DMA is done before this point in the SW.
                 * To prevent the case that we handle a stale Rx descriptor,
                 * just assert for now until we have a way to recover.
                 */
                if (!(__le32_to_cpu(rx_desc->attention.flags)
                                & RX_ATTENTION_FLAGS_MSDU_DONE)) {
                        __skb_queue_purge(amsdu);
                        return -EIO;
                }

                msdu_len_invalid = !!(__le32_to_cpu(rx_desc->attention.flags)
                                        & (RX_ATTENTION_FLAGS_MPDU_LENGTH_ERR |
                                           RX_ATTENTION_FLAGS_MSDU_LENGTH_ERR));
                msdu_len = MS(__le32_to_cpu(rx_desc->msdu_start.common.info0),
                              RX_MSDU_START_INFO0_MSDU_LENGTH);
                msdu_chained = rx_desc->frag_info.ring2_more_count;

                if (msdu_len_invalid)
                        msdu_len = 0;

                skb_trim(msdu, 0);
                skb_put(msdu, min(msdu_len, HTT_RX_MSDU_SIZE));
                msdu_len -= msdu->len;

                /* Note: Chained buffers do not contain rx descriptor */
                while (msdu_chained--) {
                        msdu = ath10k_htt_rx_netbuf_pop(htt);
                        if (!msdu) {
                                __skb_queue_purge(amsdu);
                                return -ENOENT;
                        }

                        __skb_queue_tail(amsdu, msdu);
                        skb_trim(msdu, 0);
                        skb_put(msdu, min(msdu_len, HTT_RX_BUF_SIZE));
                        msdu_len -= msdu->len;
                        msdu_chaining = 1;
                }

                last_msdu = __le32_to_cpu(rx_desc->msdu_end.common.info0) &
                                RX_MSDU_END_INFO0_LAST_MSDU;

                trace_ath10k_htt_rx_desc(ar, &rx_desc->attention,
                                         sizeof(*rx_desc) - sizeof(u32));

                if (last_msdu)
                        break;
        }

        if (skb_queue_empty(amsdu))
                msdu_chaining = -1;

        /*
         * Don't refill the ring yet.
         *
         * First, the elements popped here are still in use - it is not
         * safe to overwrite them until the matching call to
         * mpdu_desc_list_next. Second, for efficiency it is preferable to
         * refill the rx ring with 1 PPDU's worth of rx buffers (something
         * like 32 x 3 buffers), rather than one MPDU's worth of rx buffers
         * (something like 3 buffers). Consequently, we'll rely on the txrx
         * SW to tell us when it is done pulling all the PPDU's rx buffers
         * out of the rx ring, and then refill it just once.
         */

        return msdu_chaining;
}

static struct sk_buff *ath10k_htt_rx_pop_paddr(struct ath10k_htt *htt,
                                               u32 paddr)
{
        struct ath10k *ar = htt->ar;
        struct ath10k_skb_rxcb *rxcb;
        struct sk_buff *msdu;

        lockdep_assert_held(&htt->rx_ring.lock);

        msdu = ath10k_htt_rx_find_skb_paddr(ar, paddr);
        if (!msdu)
                return NULL;

        rxcb = ATH10K_SKB_RXCB(msdu);
        hash_del(&rxcb->hlist);
        htt->rx_ring.fill_cnt--;

        dma_unmap_single(htt->ar->dev, rxcb->paddr,
                         msdu->len + skb_tailroom(msdu),
                         DMA_FROM_DEVICE);
        ath10k_dbg_dump(ar, ATH10K_DBG_HTT_DUMP, NULL, "htt rx netbuf pop: ",
                        msdu->data, msdu->len + skb_tailroom(msdu));

        return msdu;
}

static int ath10k_htt_rx_pop_paddr_list(struct ath10k_htt *htt,
                                        struct htt_rx_in_ord_ind *ev,
                                        struct sk_buff_head *list)
{
        struct ath10k *ar = htt->ar;
        struct htt_rx_in_ord_msdu_desc *msdu_desc = ev->msdu_descs;
        struct htt_rx_desc *rxd;
        struct sk_buff *msdu;
        int msdu_count;
        bool is_offload;
        u32 paddr;

        lockdep_assert_held(&htt->rx_ring.lock);

        msdu_count = __le16_to_cpu(ev->msdu_count);
        is_offload = !!(ev->info & HTT_RX_IN_ORD_IND_INFO_OFFLOAD_MASK);

        while (msdu_count--) {
                paddr = __le32_to_cpu(msdu_desc->msdu_paddr);

                msdu = ath10k_htt_rx_pop_paddr(htt, paddr);
                if (!msdu) {
                        __skb_queue_purge(list);
                        return -ENOENT;
                }

                __skb_queue_tail(list, msdu);

                if (!is_offload) {
                        rxd = (void *)msdu->data;

                        trace_ath10k_htt_rx_desc(ar, rxd, sizeof(*rxd));

                        skb_put(msdu, sizeof(*rxd));
                        skb_pull(msdu, sizeof(*rxd));
                        skb_put(msdu, __le16_to_cpu(msdu_desc->msdu_len));

                        if (!(__le32_to_cpu(rxd->attention.flags) &
                              RX_ATTENTION_FLAGS_MSDU_DONE)) {
                                ath10k_warn(htt->ar, "tried to pop an incomplete frame, oops!\n");
                                return -EIO;
                        }
                }

                msdu_desc++;
        }

        return 0;
}

int ath10k_htt_rx_alloc(struct ath10k_htt *htt)
{
        struct ath10k *ar = htt->ar;
        dma_addr_t paddr;
        void *vaddr;
        size_t size;
        struct timer_list *timer = &htt->rx_ring.refill_retry_timer;

        htt->rx_confused = false;

        /* XXX: The fill level could be changed during runtime in response to
         * the host processing latency. Is this really worth it?
         */
        htt->rx_ring.size = HTT_RX_RING_SIZE;
        htt->rx_ring.size_mask = htt->rx_ring.size - 1;
        htt->rx_ring.fill_level = HTT_RX_RING_FILL_LEVEL;

        if (!is_power_of_2(htt->rx_ring.size)) {
                ath10k_warn(ar, "htt rx ring size is not power of 2\n");
                return -EINVAL;
        }

        htt->rx_ring.netbufs_ring =
                kzalloc(htt->rx_ring.size * sizeof(struct sk_buff *),
                        GFP_KERNEL);
        if (!htt->rx_ring.netbufs_ring)
                goto err_netbuf;

        size = htt->rx_ring.size * sizeof(htt->rx_ring.paddrs_ring);

        vaddr = dma_alloc_coherent(htt->ar->dev, size, &paddr, GFP_KERNEL);
        if (!vaddr)
                goto err_dma_ring;

        htt->rx_ring.paddrs_ring = vaddr;
        htt->rx_ring.base_paddr = paddr;

        vaddr = dma_alloc_coherent(htt->ar->dev,
                                   sizeof(*htt->rx_ring.alloc_idx.vaddr),
                                   &paddr, GFP_KERNEL);
        if (!vaddr)
                goto err_dma_idx;

        htt->rx_ring.alloc_idx.vaddr = vaddr;
        htt->rx_ring.alloc_idx.paddr = paddr;
        htt->rx_ring.sw_rd_idx.msdu_payld = htt->rx_ring.size_mask;
        *htt->rx_ring.alloc_idx.vaddr = 0;

        /* Initialize the Rx refill retry timer */
        setup_timer(timer, ath10k_htt_rx_ring_refill_retry, (unsigned long)htt);

        spin_lock_init(&htt->rx_ring.lock);

        htt->rx_ring.fill_cnt = 0;
        htt->rx_ring.sw_rd_idx.msdu_payld = 0;
        hash_init(htt->rx_ring.skb_table);

        skb_queue_head_init(&htt->rx_compl_q);
        skb_queue_head_init(&htt->rx_in_ord_compl_q);
        skb_queue_head_init(&htt->tx_fetch_ind_q);
        atomic_set(&htt->num_mpdus_ready, 0);

        tasklet_init(&htt->txrx_compl_task, ath10k_htt_txrx_compl_task,
                     (unsigned long)htt);

        ath10k_dbg(ar, ATH10K_DBG_BOOT, "htt rx ring size %d fill_level %d\n",
                   htt->rx_ring.size, htt->rx_ring.fill_level);
        return 0;

err_dma_idx:
        dma_free_coherent(htt->ar->dev,
                          (htt->rx_ring.size *
                           sizeof(htt->rx_ring.paddrs_ring)),
                          htt->rx_ring.paddrs_ring,
                          htt->rx_ring.base_paddr);
err_dma_ring:
        kfree(htt->rx_ring.netbufs_ring);
err_netbuf:
        return -ENOMEM;
}

static int ath10k_htt_rx_crypto_param_len(struct ath10k *ar,
                                          enum htt_rx_mpdu_encrypt_type type)
{
        switch (type) {
        case HTT_RX_MPDU_ENCRYPT_NONE:
                return 0;
        case HTT_RX_MPDU_ENCRYPT_WEP40:
        case HTT_RX_MPDU_ENCRYPT_WEP104:
                return IEEE80211_WEP_IV_LEN;
        case HTT_RX_MPDU_ENCRYPT_TKIP_WITHOUT_MIC:
        case HTT_RX_MPDU_ENCRYPT_TKIP_WPA:
                return IEEE80211_TKIP_IV_LEN;
        case HTT_RX_MPDU_ENCRYPT_AES_CCM_WPA2:
                return IEEE80211_CCMP_HDR_LEN;
        case HTT_RX_MPDU_ENCRYPT_WEP128:
        case HTT_RX_MPDU_ENCRYPT_WAPI:
                break;
        }

        ath10k_warn(ar, "unsupported encryption type %d\n", type);
        return 0;
}

#define MICHAEL_MIC_LEN 8

static int ath10k_htt_rx_crypto_tail_len(struct ath10k *ar,
                                         enum htt_rx_mpdu_encrypt_type type)
{
        switch (type) {
        case HTT_RX_MPDU_ENCRYPT_NONE:
                return 0;
        case HTT_RX_MPDU_ENCRYPT_WEP40:
        case HTT_RX_MPDU_ENCRYPT_WEP104:
                return IEEE80211_WEP_ICV_LEN;
        case HTT_RX_MPDU_ENCRYPT_TKIP_WITHOUT_MIC:
        case HTT_RX_MPDU_ENCRYPT_TKIP_WPA:
                return IEEE80211_TKIP_ICV_LEN;
        case HTT_RX_MPDU_ENCRYPT_AES_CCM_WPA2:
                return IEEE80211_CCMP_MIC_LEN;
        case HTT_RX_MPDU_ENCRYPT_WEP128:
        case HTT_RX_MPDU_ENCRYPT_WAPI:
                break;
        }

        ath10k_warn(ar, "unsupported encryption type %d\n", type);
        return 0;
}

struct amsdu_subframe_hdr {
        u8 dst[ETH_ALEN];
        u8 src[ETH_ALEN];
        __be16 len;
} __packed;

#define GROUP_ID_IS_SU_MIMO(x) ((x) == 0 || (x) == 63)

static void ath10k_htt_rx_h_rates(struct ath10k *ar,
                                  struct ieee80211_rx_status *status,
                                  struct htt_rx_desc *rxd)
{
        struct ieee80211_supported_band *sband;
        u8 cck, rate, bw, sgi, mcs, nss;
        u8 preamble = 0;
        u8 group_id;
        u32 info1, info2, info3;

        info1 = __le32_to_cpu(rxd->ppdu_start.info1);
        info2 = __le32_to_cpu(rxd->ppdu_start.info2);
        info3 = __le32_to_cpu(rxd->ppdu_start.info3);

        preamble = MS(info1, RX_PPDU_START_INFO1_PREAMBLE_TYPE);

        switch (preamble) {
        case HTT_RX_LEGACY:
                /* To get legacy rate index band is required. Since band can't
                 * be undefined check if freq is non-zero.
                 */
                if (!status->freq)
                        return;

                cck = info1 & RX_PPDU_START_INFO1_L_SIG_RATE_SELECT;
                rate = MS(info1, RX_PPDU_START_INFO1_L_SIG_RATE);
                rate &= ~RX_PPDU_START_RATE_FLAG;

                sband = &ar->mac.sbands[status->band];
                status->rate_idx = ath10k_mac_hw_rate_to_idx(sband, rate, cck);
                break;
        case HTT_RX_HT:
        case HTT_RX_HT_WITH_TXBF:
                /* HT-SIG - Table 20-11 in info2 and info3 */
                mcs = info2 & 0x1F;
                nss = mcs >> 3;
                bw = (info2 >> 7) & 1;
                sgi = (info3 >> 7) & 1;

                status->rate_idx = mcs;
                status->flag |= RX_FLAG_HT;
                if (sgi)
                        status->flag |= RX_FLAG_SHORT_GI;
                if (bw)
                        status->flag |= RX_FLAG_40MHZ;
                break;
        case HTT_RX_VHT:
        case HTT_RX_VHT_WITH_TXBF:
                /* VHT-SIG-A1 in info2, VHT-SIG-A2 in info3
                   TODO check this */
                bw = info2 & 3;
                sgi = info3 & 1;
                group_id = (info2 >> 4) & 0x3F;

                if (GROUP_ID_IS_SU_MIMO(group_id)) {
                        mcs = (info3 >> 4) & 0x0F;
                        nss = ((info2 >> 10) & 0x07) + 1;
                } else {
                        /* Hardware doesn't decode VHT-SIG-B into Rx descriptor
                         * so it's impossible to decode MCS. Also since
                         * firmware consumes Group Id Management frames host
                         * has no knowledge regarding group/user position
                         * mapping so it's impossible to pick the correct Nsts
                         * from VHT-SIG-A1.
                         *
                         * Bandwidth and SGI are valid so report the rateinfo
                         * on best-effort basis.
                         */
                        mcs = 0;
                        nss = 1;
                }

                if (mcs > 0x09) {
                        ath10k_warn(ar, "invalid MCS received %u\n", mcs);
                        ath10k_warn(ar, "rxd %08x mpdu start %08x %08x msdu start %08x %08x ppdu start %08x %08x %08x %08x %08x\n",
                                    __le32_to_cpu(rxd->attention.flags),
                                    __le32_to_cpu(rxd->mpdu_start.info0),
                                    __le32_to_cpu(rxd->mpdu_start.info1),
                                    __le32_to_cpu(rxd->msdu_start.common.info0),
                                    __le32_to_cpu(rxd->msdu_start.common.info1),
                                    rxd->ppdu_start.info0,
                                    __le32_to_cpu(rxd->ppdu_start.info1),
                                    __le32_to_cpu(rxd->ppdu_start.info2),
                                    __le32_to_cpu(rxd->ppdu_start.info3),
                                    __le32_to_cpu(rxd->ppdu_start.info4));

                        ath10k_warn(ar, "msdu end %08x mpdu end %08x\n",
                                    __le32_to_cpu(rxd->msdu_end.common.info0),
                                    __le32_to_cpu(rxd->mpdu_end.info0));

                        ath10k_dbg_dump(ar, ATH10K_DBG_HTT_DUMP, NULL,
                                        "rx desc msdu payload: ",
                                        rxd->msdu_payload, 50);
                }

                status->rate_idx = mcs;
                status->vht_nss = nss;

                if (sgi)
                        status->flag |= RX_FLAG_SHORT_GI;

                switch (bw) {
                /* 20MHZ */
                case 0:
                        break;
                /* 40MHZ */
                case 1:
                        status->flag |= RX_FLAG_40MHZ;
                        break;
                /* 80MHZ */
                case 2:
                        status->vht_flag |= RX_VHT_FLAG_80MHZ;
                }

                status->flag |= RX_FLAG_VHT;
                break;
        default:
                break;
        }
}

static struct ieee80211_channel *
ath10k_htt_rx_h_peer_channel(struct ath10k *ar, struct htt_rx_desc *rxd)
{
        struct ath10k_peer *peer;
        struct ath10k_vif *arvif;
        struct cfg80211_chan_def def;
        u16 peer_id;

        lockdep_assert_held(&ar->data_lock);

        if (!rxd)
                return NULL;

        if (rxd->attention.flags &
            __cpu_to_le32(RX_ATTENTION_FLAGS_PEER_IDX_INVALID))
                return NULL;

        if (!(rxd->msdu_end.common.info0 &
              __cpu_to_le32(RX_MSDU_END_INFO0_FIRST_MSDU)))
                return NULL;

        peer_id = MS(__le32_to_cpu(rxd->mpdu_start.info0),
                     RX_MPDU_START_INFO0_PEER_IDX);

        peer = ath10k_peer_find_by_id(ar, peer_id);
        if (!peer)
                return NULL;

        arvif = ath10k_get_arvif(ar, peer->vdev_id);
        if (WARN_ON_ONCE(!arvif))
                return NULL;

        if (WARN_ON(ath10k_mac_vif_chan(arvif->vif, &def)))
                return NULL;

        return def.chan;
}

static struct ieee80211_channel *
ath10k_htt_rx_h_vdev_channel(struct ath10k *ar, u32 vdev_id)
{
        struct ath10k_vif *arvif;
        struct cfg80211_chan_def def;

        lockdep_assert_held(&ar->data_lock);

        list_for_each_entry(arvif, &ar->arvifs, list) {
                if (arvif->vdev_id == vdev_id &&
                    ath10k_mac_vif_chan(arvif->vif, &def) == 0)
                        return def.chan;
        }

        return NULL;
}

static void
ath10k_htt_rx_h_any_chan_iter(struct ieee80211_hw *hw,
                              struct ieee80211_chanctx_conf *conf,
                              void *data)
{
        struct cfg80211_chan_def *def = data;

        *def = conf->def;
}

static struct ieee80211_channel *
ath10k_htt_rx_h_any_channel(struct ath10k *ar)
{
        struct cfg80211_chan_def def = {};

        ieee80211_iter_chan_contexts_atomic(ar->hw,
                                            ath10k_htt_rx_h_any_chan_iter,
                                            &def);

        return def.chan;
}

static bool ath10k_htt_rx_h_channel(struct ath10k *ar,
                                    struct ieee80211_rx_status *status,
                                    struct htt_rx_desc *rxd,
                                    u32 vdev_id)
{
        struct ieee80211_channel *ch;

        spin_lock_bh(&ar->data_lock);
        ch = ar->scan_channel;
        if (!ch)
                ch = ar->rx_channel;
        if (!ch)
                ch = ath10k_htt_rx_h_peer_channel(ar, rxd);
        if (!ch)
                ch = ath10k_htt_rx_h_vdev_channel(ar, vdev_id);
        if (!ch)
                ch = ath10k_htt_rx_h_any_channel(ar);
        if (!ch)
                ch = ar->tgt_oper_chan;
        spin_unlock_bh(&ar->data_lock);

        if (!ch)
                return false;

        status->band = ch->band;
        status->freq = ch->center_freq;

        return true;
}

static void ath10k_htt_rx_h_signal(struct ath10k *ar,
                                   struct ieee80211_rx_status *status,
                                   struct htt_rx_desc *rxd)
{
        /* FIXME: Get real NF */
        status->signal = ATH10K_DEFAULT_NOISE_FLOOR +
                         rxd->ppdu_start.rssi_comb;
        status->flag &= ~RX_FLAG_NO_SIGNAL_VAL;
}

static void ath10k_htt_rx_h_mactime(struct ath10k *ar,
                                    struct ieee80211_rx_status *status,
                                    struct htt_rx_desc *rxd)
{
        /* FIXME: TSF is known only at the end of PPDU, in the last MPDU. This
         * means all prior MSDUs in a PPDU are reported to mac80211 without the
         * TSF. Is it worth holding frames until end of PPDU is known?
         *
         * FIXME: Can we get/compute 64bit TSF?
         */
        status->mactime = __le32_to_cpu(rxd->ppdu_end.common.tsf_timestamp);
        status->flag |= RX_FLAG_MACTIME_END;
}

static void ath10k_htt_rx_h_ppdu(struct ath10k *ar,
                                 struct sk_buff_head *amsdu,
                                 struct ieee80211_rx_status *status,
                                 u32 vdev_id)
{
        struct sk_buff *first;
        struct htt_rx_desc *rxd;
        bool is_first_ppdu;
        bool is_last_ppdu;

        if (skb_queue_empty(amsdu))
                return;

        first = skb_peek(amsdu);
        rxd = (void *)first->data - sizeof(*rxd);

        is_first_ppdu = !!(rxd->attention.flags &
                           __cpu_to_le32(RX_ATTENTION_FLAGS_FIRST_MPDU));
        is_last_ppdu = !!(rxd->attention.flags &
                          __cpu_to_le32(RX_ATTENTION_FLAGS_LAST_MPDU));

        if (is_first_ppdu) {
                /* New PPDU starts so clear out the old per-PPDU status. */
                status->freq = 0;
                status->rate_idx = 0;
                status->vht_nss = 0;
                status->vht_flag &= ~RX_VHT_FLAG_80MHZ;
                status->flag &= ~(RX_FLAG_HT |
                                  RX_FLAG_VHT |
                                  RX_FLAG_SHORT_GI |
                                  RX_FLAG_40MHZ |
                                  RX_FLAG_MACTIME_END);
                status->flag |= RX_FLAG_NO_SIGNAL_VAL;

                ath10k_htt_rx_h_signal(ar, status, rxd);
                ath10k_htt_rx_h_channel(ar, status, rxd, vdev_id);
                ath10k_htt_rx_h_rates(ar, status, rxd);
        }

        if (is_last_ppdu)
                ath10k_htt_rx_h_mactime(ar, status, rxd);
}

static const char * const tid_to_ac[] = {
        "BE",
        "BK",
        "BK",
        "BE",
        "VI",
        "VI",
        "VO",
        "VO",
};

static char *ath10k_get_tid(struct ieee80211_hdr *hdr, char *out, size_t size)
{
        u8 *qc;
        int tid;

        if (!ieee80211_is_data_qos(hdr->frame_control))
                return "";

        qc = ieee80211_get_qos_ctl(hdr);
        tid = *qc & IEEE80211_QOS_CTL_TID_MASK;
        if (tid < 8)
                snprintf(out, size, "tid %d (%s)", tid, tid_to_ac[tid]);
        else
                snprintf(out, size, "tid %d", tid);

        return out;
}

static void ath10k_process_rx(struct ath10k *ar,
                              struct ieee80211_rx_status *rx_status,
                              struct sk_buff *skb)
{
        struct ieee80211_rx_status *status;
        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
        char tid[32];

        status = IEEE80211_SKB_RXCB(skb);
        *status = *rx_status;

        ath10k_dbg(ar, ATH10K_DBG_DATA,
                   "rx skb %p len %u peer %pM %s %s sn %u %s%s%s%s%s %srate_idx %u vht_nss %u freq %u band %u flag 0x%llx fcs-err %i mic-err %i amsdu-more %i\n",
                   skb,
                   skb->len,
                   ieee80211_get_SA(hdr),
                   ath10k_get_tid(hdr, tid, sizeof(tid)),
                   is_multicast_ether_addr(ieee80211_get_DA(hdr)) ?
                                                        "mcast" : "ucast",
                   (__le16_to_cpu(hdr->seq_ctrl) & IEEE80211_SCTL_SEQ) >> 4,
                   status->flag == 0 ? "legacy" : "",
                   status->flag & RX_FLAG_HT ? "ht" : "",
                   status->flag & RX_FLAG_VHT ? "vht" : "",
                   status->flag & RX_FLAG_40MHZ ? "40" : "",
                   status->vht_flag & RX_VHT_FLAG_80MHZ ? "80" : "",
                   status->flag & RX_FLAG_SHORT_GI ? "sgi " : "",
                   status->rate_idx,
                   status->vht_nss,
                   status->freq,
                   status->band, status->flag,
                   !!(status->flag & RX_FLAG_FAILED_FCS_CRC),
                   !!(status->flag & RX_FLAG_MMIC_ERROR),
                   !!(status->flag & RX_FLAG_AMSDU_MORE));
        ath10k_dbg_dump(ar, ATH10K_DBG_HTT_DUMP, NULL, "rx skb: ",
                        skb->data, skb->len);
        trace_ath10k_rx_hdr(ar, skb->data, skb->len);
        trace_ath10k_rx_payload(ar, skb->data, skb->len);

        ieee80211_rx(ar->hw, skb);
}

static int ath10k_htt_rx_nwifi_hdrlen(struct ath10k *ar,
                                      struct ieee80211_hdr *hdr)
{
        int len = ieee80211_hdrlen(hdr->frame_control);

        if (!test_bit(ATH10K_FW_FEATURE_NO_NWIFI_DECAP_4ADDR_PADDING,
                      ar->running_fw->fw_file.fw_features))
                len = round_up(len, 4);

        return len;
}

static void ath10k_htt_rx_h_undecap_raw(struct ath10k *ar,
                                        struct sk_buff *msdu,
                                        struct ieee80211_rx_status *status,
                                        enum htt_rx_mpdu_encrypt_type enctype,
                                        bool is_decrypted)
{
        struct ieee80211_hdr *hdr;
        struct htt_rx_desc *rxd;
        size_t hdr_len;
        size_t crypto_len;
        bool is_first;
        bool is_last;

        rxd = (void *)msdu->data - sizeof(*rxd);
        is_first = !!(rxd->msdu_end.common.info0 &
                      __cpu_to_le32(RX_MSDU_END_INFO0_FIRST_MSDU));
        is_last = !!(rxd->msdu_end.common.info0 &
                     __cpu_to_le32(RX_MSDU_END_INFO0_LAST_MSDU));

        /* Delivered decapped frame:
         * [802.11 header]
         * [crypto param] <-- can be trimmed if !fcs_err &&
         *                    !decrypt_err && !peer_idx_invalid
         * [amsdu header] <-- only if A-MSDU
         * [rfc1042/llc]
         * [payload]

         * [FCS] <-- at end, needs to be trimmed
         */

        /* This probably shouldn't happen but warn just in case */
        if (unlikely(WARN_ON_ONCE(!is_first)))
                return;

        /* This probably shouldn't happen but warn just in case */
        if (unlikely(WARN_ON_ONCE(!(is_first && is_last))))
                return;

        skb_trim(msdu, msdu->len - FCS_LEN);

        /* In most cases this will be true for sniffed frames. It makes sense
         * to deliver them as-is without stripping the crypto param. This is
         * necessary for software based decryption.
         *
         * If there's no error then the frame is decrypted. At least that is
         * the case for frames that come in via fragmented rx indication.
         */
        if (!is_decrypted)
                return;

        /* The payload is decrypted so strip crypto params. Start from tail
         * since hdr is used to compute some stuff.
         */

        hdr = (void *)msdu->data;

        /* Tail */
        if (status->flag & RX_FLAG_IV_STRIPPED)
                skb_trim(msdu, msdu->len -
                         ath10k_htt_rx_crypto_tail_len(ar, enctype));

        /* MMIC */
        if ((status->flag & RX_FLAG_MMIC_STRIPPED) &&
            !ieee80211_has_morefrags(hdr->frame_control) &&
            enctype == HTT_RX_MPDU_ENCRYPT_TKIP_WPA)
                skb_trim(msdu, msdu->len - 8);

        /* Head */
        if (status->flag & RX_FLAG_IV_STRIPPED) {
                hdr_len = ieee80211_hdrlen(hdr->frame_control);
                crypto_len = ath10k_htt_rx_crypto_param_len(ar, enctype);

                memmove((void *)msdu->data + crypto_len,
                        (void *)msdu->data, hdr_len);
                skb_pull(msdu, crypto_len);
        }
}

static void ath10k_htt_rx_h_undecap_nwifi(struct ath10k *ar,
                                          struct sk_buff *msdu,
                                          struct ieee80211_rx_status *status,
                                          const u8 first_hdr[64])
{
        struct ieee80211_hdr *hdr;
        size_t hdr_len;
        u8 da[ETH_ALEN];
        u8 sa[ETH_ALEN];

        /* Delivered decapped frame:
         * [nwifi 802.11 header] <-- replaced with 802.11 hdr
         * [rfc1042/llc]
         *
         * Note: The nwifi header doesn't have QoS Control and is
         * (always?) a 3addr frame.
         *
         * Note2: There's no A-MSDU subframe header. Even if it's part
         * of an A-MSDU.
         */

        /* pull decapped header and copy SA & DA */
        if ((ar->hw_params.hw_4addr_pad == ATH10K_HW_4ADDR_PAD_BEFORE) &&
            ieee80211_has_a4(((struct ieee80211_hdr *)first_hdr)->frame_control)) {
                /* The QCA99X0 4 address mode pad 2 bytes at the
                 * beginning of MSDU
                 */
                hdr = (struct ieee80211_hdr *)(msdu->data + 2);
                /* The skb length need be extended 2 as the 2 bytes at the tail
                 * be excluded due to the padding
                 */
                skb_put(msdu, 2);
        } else {
                hdr = (struct ieee80211_hdr *)(msdu->data);
        }

        hdr_len = ath10k_htt_rx_nwifi_hdrlen(ar, hdr);
        ether_addr_copy(da, ieee80211_get_DA(hdr));
        ether_addr_copy(sa, ieee80211_get_SA(hdr));
        skb_pull(msdu, hdr_len);

        /* push original 802.11 header */
        hdr = (struct ieee80211_hdr *)first_hdr;
        hdr_len = ieee80211_hdrlen(hdr->frame_control);
        memcpy(skb_push(msdu, hdr_len), hdr, hdr_len);

        /* original 802.11 header has a different DA and in
         * case of 4addr it may also have different SA
         */
        hdr = (struct ieee80211_hdr *)msdu->data;
        ether_addr_copy(ieee80211_get_DA(hdr), da);
        ether_addr_copy(ieee80211_get_SA(hdr), sa);
}

static void *ath10k_htt_rx_h_find_rfc1042(struct ath10k *ar,
                                          struct sk_buff *msdu,
                                          enum htt_rx_mpdu_encrypt_type enctype)
{
        struct ieee80211_hdr *hdr;
        struct htt_rx_desc *rxd;
        size_t hdr_len, crypto_len;
        void *rfc1042;
        bool is_first, is_last, is_amsdu;

        rxd = (void *)msdu->data - sizeof(*rxd);
        hdr = (void *)rxd->rx_hdr_status;

        is_first = !!(rxd->msdu_end.common.info0 &
                      __cpu_to_le32(RX_MSDU_END_INFO0_FIRST_MSDU));
        is_last = !!(rxd->msdu_end.common.info0 &
                     __cpu_to_le32(RX_MSDU_END_INFO0_LAST_MSDU));
        is_amsdu = !(is_first && is_last);

        rfc1042 = hdr;

        if (is_first) {
                hdr_len = ieee80211_hdrlen(hdr->frame_control);
                crypto_len = ath10k_htt_rx_crypto_param_len(ar, enctype);

                rfc1042 += round_up(hdr_len, 4) +
                           round_up(crypto_len, 4);
        }

        if (is_amsdu)
                rfc1042 += sizeof(struct amsdu_subframe_hdr);

        return rfc1042;
}

static void ath10k_htt_rx_h_undecap_eth(struct ath10k *ar,
                                        struct sk_buff *msdu,
                                        struct ieee80211_rx_status *status,
                                        const u8 first_hdr[64],
                                        enum htt_rx_mpdu_encrypt_type enctype)
{
        struct ieee80211_hdr *hdr;
        struct ethhdr *eth;
        size_t hdr_len;
        void *rfc1042;
        u8 da[ETH_ALEN];
        u8 sa[ETH_ALEN];

        /* Delivered decapped frame:
         * [eth header] <-- replaced with 802.11 hdr & rfc1042/llc
         * [payload]
         */

        rfc1042 = ath10k_htt_rx_h_find_rfc1042(ar, msdu, enctype);
        if (WARN_ON_ONCE(!rfc1042))
                return;

        /* pull decapped header and copy SA & DA */
        eth = (struct ethhdr *)msdu->data;
        ether_addr_copy(da, eth->h_dest);
        ether_addr_copy(sa, eth->h_source);
        skb_pull(msdu, sizeof(struct ethhdr));

        /* push rfc1042/llc/snap */
        memcpy(skb_push(msdu, sizeof(struct rfc1042_hdr)), rfc1042,
               sizeof(struct rfc1042_hdr));

        /* push original 802.11 header */
        hdr = (struct ieee80211_hdr *)first_hdr;
        hdr_len = ieee80211_hdrlen(hdr->frame_control);
        memcpy(skb_push(msdu, hdr_len), hdr, hdr_len);

        /* original 802.11 header has a different DA and in
         * case of 4addr it may also have different SA
         */
        hdr = (struct ieee80211_hdr *)msdu->data;
        ether_addr_copy(ieee80211_get_DA(hdr), da);
        ether_addr_copy(ieee80211_get_SA(hdr), sa);
}

static void ath10k_htt_rx_h_undecap_snap(struct ath10k *ar,
                                         struct sk_buff *msdu,
                                         struct ieee80211_rx_status *status,
                                         const u8 first_hdr[64])
{
        struct ieee80211_hdr *hdr;
        size_t hdr_len;

        /* Delivered decapped frame:
         * [amsdu header] <-- replaced with 802.11 hdr
         * [rfc1042/llc]
         * [payload]
         */

        skb_pull(msdu, sizeof(struct amsdu_subframe_hdr));

        hdr = (struct ieee80211_hdr *)first_hdr;
        hdr_len = ieee80211_hdrlen(hdr->frame_control);
        memcpy(skb_push(msdu, hdr_len), hdr, hdr_len);
}

static void ath10k_htt_rx_h_undecap(struct ath10k *ar,
                                    struct sk_buff *msdu,
                                    struct ieee80211_rx_status *status,
                                    u8 first_hdr[64],
                                    enum htt_rx_mpdu_encrypt_type enctype,
                                    bool is_decrypted)
{
        struct htt_rx_desc *rxd;
        enum rx_msdu_decap_format decap;

        /* First msdu's decapped header:
         * [802.11 header] <-- padded to 4 bytes long
         * [crypto param] <-- padded to 4 bytes long
         * [amsdu header] <-- only if A-MSDU
         * [rfc1042/llc]
         *
         * Other (2nd, 3rd, ..) msdu's decapped header:
         * [amsdu header] <-- only if A-MSDU
         * [rfc1042/llc]
         */

        rxd = (void *)msdu->data - sizeof(*rxd);
        decap = MS(__le32_to_cpu(rxd->msdu_start.common.info1),
                   RX_MSDU_START_INFO1_DECAP_FORMAT);

        switch (decap) {
        case RX_MSDU_DECAP_RAW:
                ath10k_htt_rx_h_undecap_raw(ar, msdu, status, enctype,
                                            is_decrypted);
                break;
        case RX_MSDU_DECAP_NATIVE_WIFI:
                ath10k_htt_rx_h_undecap_nwifi(ar, msdu, status, first_hdr);
                break;
        case RX_MSDU_DECAP_ETHERNET2_DIX:
                ath10k_htt_rx_h_undecap_eth(ar, msdu, status, first_hdr, enctype);
                break;
        case RX_MSDU_DECAP_8023_SNAP_LLC:
                ath10k_htt_rx_h_undecap_snap(ar, msdu, status, first_hdr);
                break;
        }
}

static int ath10k_htt_rx_get_csum_state(struct sk_buff *skb)
{
        struct htt_rx_desc *rxd;
        u32 flags, info;
        bool is_ip4, is_ip6;
        bool is_tcp, is_udp;
        bool ip_csum_ok, tcpudp_csum_ok;

        rxd = (void *)skb->data - sizeof(*rxd);
        flags = __le32_to_cpu(rxd->attention.flags);
        info = __le32_to_cpu(rxd->msdu_start.common.info1);

        is_ip4 = !!(info & RX_MSDU_START_INFO1_IPV4_PROTO);
        is_ip6 = !!(info & RX_MSDU_START_INFO1_IPV6_PROTO);
        is_tcp = !!(info & RX_MSDU_START_INFO1_TCP_PROTO);
        is_udp = !!(info & RX_MSDU_START_INFO1_UDP_PROTO);
        ip_csum_ok = !(flags & RX_ATTENTION_FLAGS_IP_CHKSUM_FAIL);
        tcpudp_csum_ok = !(flags & RX_ATTENTION_FLAGS_TCP_UDP_CHKSUM_FAIL);

        if (!is_ip4 && !is_ip6)
                return CHECKSUM_NONE;
        if (!is_tcp && !is_udp)
                return CHECKSUM_NONE;
        if (!ip_csum_ok)
                return CHECKSUM_NONE;
        if (!tcpudp_csum_ok)
                return CHECKSUM_NONE;

        return CHECKSUM_UNNECESSARY;
}

static void ath10k_htt_rx_h_csum_offload(struct sk_buff *msdu)
{
        msdu->ip_summed = ath10k_htt_rx_get_csum_state(msdu);
}

static void ath10k_htt_rx_h_mpdu(struct ath10k *ar,
                                 struct sk_buff_head *amsdu,
                                 struct ieee80211_rx_status *status)
{
        struct sk_buff *first;
        struct sk_buff *last;
        struct sk_buff *msdu;
        struct htt_rx_desc *rxd;
        struct ieee80211_hdr *hdr;
        enum htt_rx_mpdu_encrypt_type enctype;
        u8 first_hdr[64];
        u8 *qos;
        size_t hdr_len;
        bool has_fcs_err;
        bool has_crypto_err;
        bool has_tkip_err;
        bool has_peer_idx_invalid;
        bool is_decrypted;
        bool is_mgmt;
        u32 attention;

        if (skb_queue_empty(amsdu))
                return;

        first = skb_peek(amsdu);
        rxd = (void *)first->data - sizeof(*rxd);

        is_mgmt = !!(rxd->attention.flags &
                     __cpu_to_le32(RX_ATTENTION_FLAGS_MGMT_TYPE));

        enctype = MS(__le32_to_cpu(rxd->mpdu_start.info0),
                     RX_MPDU_START_INFO0_ENCRYPT_TYPE);

        /* First MSDU's Rx descriptor in an A-MSDU contains full 802.11
         * decapped header. It'll be used for undecapping of each MSDU.
         */
        hdr = (void *)rxd->rx_hdr_status;
        hdr_len = ieee80211_hdrlen(hdr->frame_control);
        memcpy(first_hdr, hdr, hdr_len);

        /* Each A-MSDU subframe will use the original header as the base and be
         * reported as a separate MSDU so strip the A-MSDU bit from QoS Ctl.
         */
        hdr = (void *)first_hdr;
        qos = ieee80211_get_qos_ctl(hdr);
        qos[0] &= ~IEEE80211_QOS_CTL_A_MSDU_PRESENT;

        /* Some attention flags are valid only in the last MSDU. */
        last = skb_peek_tail(amsdu);
        rxd = (void *)last->data - sizeof(*rxd);
        attention = __le32_to_cpu(rxd->attention.flags);

        has_fcs_err = !!(attention & RX_ATTENTION_FLAGS_FCS_ERR);
        has_crypto_err = !!(attention & RX_ATTENTION_FLAGS_DECRYPT_ERR);
        has_tkip_err = !!(attention & RX_ATTENTION_FLAGS_TKIP_MIC_ERR);
        has_peer_idx_invalid = !!(attention & RX_ATTENTION_FLAGS_PEER_IDX_INVALID);

        /* Note: If hardware captures an encrypted frame that it can't decrypt,
         * e.g. due to fcs error, missing peer or invalid key data it will
         * report the frame as raw.
         */
        is_decrypted = (enctype != HTT_RX_MPDU_ENCRYPT_NONE &&
                        !has_fcs_err &&
                        !has_crypto_err &&
                        !has_peer_idx_invalid);

        /* Clear per-MPDU flags while leaving per-PPDU flags intact. */
        status->flag &= ~(RX_FLAG_FAILED_FCS_CRC |
                          RX_FLAG_MMIC_ERROR |
                          RX_FLAG_DECRYPTED |
                          RX_FLAG_IV_STRIPPED |
                          RX_FLAG_ONLY_MONITOR |
                          RX_FLAG_MMIC_STRIPPED);

        if (has_fcs_err)
                status->flag |= RX_FLAG_FAILED_FCS_CRC;

        if (has_tkip_err)
                status->flag |= RX_FLAG_MMIC_ERROR;

        /* Firmware reports all necessary management frames via WMI already.
         * They are not reported to monitor interfaces at all so pass the ones
         * coming via HTT to monitor interfaces instead. This simplifies
         * matters a lot.
         */
        if (is_mgmt)
                status->flag |= RX_FLAG_ONLY_MONITOR;

        if (is_decrypted) {
                status->flag |= RX_FLAG_DECRYPTED;

                if (likely(!is_mgmt))
                        status->flag |= RX_FLAG_IV_STRIPPED |
                                        RX_FLAG_MMIC_STRIPPED;
}

        skb_queue_walk(amsdu, msdu) {
                ath10k_htt_rx_h_csum_offload(msdu);
                ath10k_htt_rx_h_undecap(ar, msdu, status, first_hdr, enctype,
                                        is_decrypted);

                /* Undecapping involves copying the original 802.11 header back
                 * to sk_buff. If frame is protected and hardware has decrypted
                 * it then remove the protected bit.
                 */
                if (!is_decrypted)
                        continue;
                if (is_mgmt)
                        continue;

                hdr = (void *)msdu->data;
                hdr->frame_control &= ~__cpu_to_le16(IEEE80211_FCTL_PROTECTED);
        }
}

static void ath10k_htt_rx_h_deliver(struct ath10k *ar,
                                    struct sk_buff_head *amsdu,
                                    struct ieee80211_rx_status *status)
{
        struct sk_buff *msdu;

        while ((msdu = __skb_dequeue(amsdu))) {
                /* Setup per-MSDU flags */
                if (skb_queue_empty(amsdu))
                        status->flag &= ~RX_FLAG_AMSDU_MORE;
                else
                        status->flag |= RX_FLAG_AMSDU_MORE;

                ath10k_process_rx(ar, status, msdu);
        }
}

static int ath10k_unchain_msdu(struct sk_buff_head *amsdu)
{
        struct sk_buff *skb, *first;
        int space;
        int total_len = 0;

        /* TODO:  Might could optimize this by using
         * skb_try_coalesce or similar method to
         * decrease copying, or maybe get mac80211 to
         * provide a way to just receive a list of
         * skb?
         */

        first = __skb_dequeue(amsdu);

        /* Allocate total length all at once. */
        skb_queue_walk(amsdu, skb)
                total_len += skb->len;

        space = total_len - skb_tailroom(first);
        if ((space > 0) &&
            (pskb_expand_head(first, 0, space, GFP_ATOMIC) < 0)) {
                /* TODO:  bump some rx-oom error stat */
                /* put it back together so we can free the
                 * whole list at once.
                 */
                __skb_queue_head(amsdu, first);
                return -1;
        }

        /* Walk list again, copying contents into
         * msdu_head
         */
        while ((skb = __skb_dequeue(amsdu))) {
                skb_copy_from_linear_data(skb, skb_put(first, skb->len),
                                          skb->len);
                dev_kfree_skb_any(skb);
        }

        __skb_queue_head(amsdu, first);
        return 0;
}

static void ath10k_htt_rx_h_unchain(struct ath10k *ar,
                                    struct sk_buff_head *amsdu,
                                    bool chained)
{
        struct sk_buff *first;
        struct htt_rx_desc *rxd;
        enum rx_msdu_decap_format decap;

        first = skb_peek(amsdu);
        rxd = (void *)first->data - sizeof(*rxd);
        decap = MS(__le32_to_cpu(rxd->msdu_start.common.info1),
                   RX_MSDU_START_INFO1_DECAP_FORMAT);

        if (!chained)
                return;

        /* FIXME: Current unchaining logic can only handle simple case of raw
         * msdu chaining. If decapping is other than raw the chaining may be
         * more complex and this isn't handled by the current code. Don't even
         * try re-constructing such frames - it'll be pretty much garbage.
         */
        if (decap != RX_MSDU_DECAP_RAW ||
            skb_queue_len(amsdu) != 1 + rxd->frag_info.ring2_more_count) {
                __skb_queue_purge(amsdu);
                return;
        }

        ath10k_unchain_msdu(amsdu);
}

static bool ath10k_htt_rx_amsdu_allowed(struct ath10k *ar,
                                        struct sk_buff_head *amsdu,
                                        struct ieee80211_rx_status *rx_status)
{
        /* FIXME: It might be a good idea to do some fuzzy-testing to drop
         * invalid/dangerous frames.
         */

        if (!rx_status->freq) {
                ath10k_warn(ar, "no channel configured; ignoring frame(s)!\n");
                return false;
        }

        if (test_bit(ATH10K_CAC_RUNNING, &ar->dev_flags)) {
                ath10k_dbg(ar, ATH10K_DBG_HTT, "htt rx cac running\n");
                return false;
        }

        return true;
}

static void ath10k_htt_rx_h_filter(struct ath10k *ar,
                                   struct sk_buff_head *amsdu,
                                   struct ieee80211_rx_status *rx_status)
{
        if (skb_queue_empty(amsdu))
                return;

        if (ath10k_htt_rx_amsdu_allowed(ar, amsdu, rx_status))
                return;

        __skb_queue_purge(amsdu);
}

static int ath10k_htt_rx_handle_amsdu(struct ath10k_htt *htt)
{
        struct ath10k *ar = htt->ar;
        static struct ieee80211_rx_status rx_status;
        struct sk_buff_head amsdu;
        int ret;

        __skb_queue_head_init(&amsdu);

        spin_lock_bh(&htt->rx_ring.lock);
        if (htt->rx_confused) {
                spin_unlock_bh(&htt->rx_ring.lock);
                return -EIO;
        }
        ret = ath10k_htt_rx_amsdu_pop(htt, &amsdu);
        spin_unlock_bh(&htt->rx_ring.lock);

        if (ret < 0) {
                ath10k_warn(ar, "rx ring became corrupted: %d\n", ret);
                __skb_queue_purge(&amsdu);
                /* FIXME: It's probably a good idea to reboot the
                 * device instead of leaving it inoperable.
                 */
                htt->rx_confused = true;
                return ret;
        }

        ath10k_htt_rx_h_ppdu(ar, &amsdu, &rx_status, 0xffff);
        ath10k_htt_rx_h_unchain(ar, &amsdu, ret > 0);
        ath10k_htt_rx_h_filter(ar, &amsdu, &rx_status);
        ath10k_htt_rx_h_mpdu(ar, &amsdu, &rx_status);
        ath10k_htt_rx_h_deliver(ar, &amsdu, &rx_status);

        return 0;
}

static void ath10k_htt_rx_proc_rx_ind(struct ath10k_htt *htt,
                                      struct htt_rx_indication *rx)
{
        struct ath10k *ar = htt->ar;
        struct htt_rx_indication_mpdu_range *mpdu_ranges;
        int num_mpdu_ranges;
        int i, mpdu_count = 0;

        num_mpdu_ranges = MS(__le32_to_cpu(rx->hdr.info1),
                             HTT_RX_INDICATION_INFO1_NUM_MPDU_RANGES);
        mpdu_ranges = htt_rx_ind_get_mpdu_ranges(rx);

        ath10k_dbg_dump(ar, ATH10K_DBG_HTT_DUMP, NULL, "htt rx ind: ",
                        rx, sizeof(*rx) +
                        (sizeof(struct htt_rx_indication_mpdu_range) *
                                num_mpdu_ranges));

        for (i = 0; i < num_mpdu_ranges; i++)
                mpdu_count += mpdu_ranges[i].mpdu_count;

        atomic_add(mpdu_count, &htt->num_mpdus_ready);

        tasklet_schedule(&htt->txrx_compl_task);
}

static void ath10k_htt_rx_frag_handler(struct ath10k_htt *htt)
{
        atomic_inc(&htt->num_mpdus_ready);

        tasklet_schedule(&htt->txrx_compl_task);
}

static void ath10k_htt_rx_tx_compl_ind(struct ath10k *ar,
                                       struct sk_buff *skb)
{
        struct ath10k_htt *htt = &ar->htt;
        struct htt_resp *resp = (struct htt_resp *)skb->data;
        struct htt_tx_done tx_done = {};
        int status = MS(resp->data_tx_completion.flags, HTT_DATA_TX_STATUS);
        __le16 msdu_id;
        int i;

        switch (status) {
        case HTT_DATA_TX_STATUS_NO_ACK:
                tx_done.status = HTT_TX_COMPL_STATE_NOACK;
                break;
        case HTT_DATA_TX_STATUS_OK:
                tx_done.status = HTT_TX_COMPL_STATE_ACK;
                break;
        case HTT_DATA_TX_STATUS_DISCARD:
        case HTT_DATA_TX_STATUS_POSTPONE:
        case HTT_DATA_TX_STATUS_DOWNLOAD_FAIL:
                tx_done.status = HTT_TX_COMPL_STATE_DISCARD;
                break;
        default:
                ath10k_warn(ar, "unhandled tx completion status %d\n", status);
                tx_done.status = HTT_TX_COMPL_STATE_DISCARD;
                break;
        }

        ath10k_dbg(ar, ATH10K_DBG_HTT, "htt tx completion num_msdus %d\n",
                   resp->data_tx_completion.num_msdus);

        for (i = 0; i < resp->data_tx_completion.num_msdus; i++) {
                msdu_id = resp->data_tx_completion.msdus[i];
                tx_done.msdu_id = __le16_to_cpu(msdu_id);

                /* kfifo_put: In practice firmware shouldn't fire off per-CE
                 * interrupt and main interrupt (MSI/-X range case) for the same
                 * HTC service so it should be safe to use kfifo_put w/o lock.
                 *
                 * From kfifo_put() documentation:
                 *  Note that with only one concurrent reader and one concurrent
                 *  writer, you don't need extra locking to use these macro.
                 */
                if (!kfifo_put(&htt->txdone_fifo, tx_done)) {
                        ath10k_warn(ar, "txdone fifo overrun, msdu_id %d status %d\n",
                                    tx_done.msdu_id, tx_done.status);
                        ath10k_txrx_tx_unref(htt, &tx_done);
                }
        }
}

static void ath10k_htt_rx_addba(struct ath10k *ar, struct htt_resp *resp)
{
        struct htt_rx_addba *ev = &resp->rx_addba;
        struct ath10k_peer *peer;
        struct ath10k_vif *arvif;
        u16 info0, tid, peer_id;

        info0 = __le16_to_cpu(ev->info0);
        tid = MS(info0, HTT_RX_BA_INFO0_TID);
        peer_id = MS(info0, HTT_RX_BA_INFO0_PEER_ID);

        ath10k_dbg(ar, ATH10K_DBG_HTT,
                   "htt rx addba tid %hu peer_id %hu size %hhu\n",
                   tid, peer_id, ev->window_size);

        spin_lock_bh(&ar->data_lock);
        peer = ath10k_peer_find_by_id(ar, peer_id);
        if (!peer) {
                ath10k_warn(ar, "received addba event for invalid peer_id: %hu\n",
                            peer_id);
                spin_unlock_bh(&ar->data_lock);
                return;
        }

        arvif = ath10k_get_arvif(ar, peer->vdev_id);
        if (!arvif) {
                ath10k_warn(ar, "received addba event for invalid vdev_id: %u\n",
                            peer->vdev_id);
                spin_unlock_bh(&ar->data_lock);
                return;
        }

        ath10k_dbg(ar, ATH10K_DBG_HTT,
                   "htt rx start rx ba session sta %pM tid %hu size %hhu\n",
                   peer->addr, tid, ev->window_size);

        ieee80211_start_rx_ba_session_offl(arvif->vif, peer->addr, tid);
        spin_unlock_bh(&ar->data_lock);
}

static void ath10k_htt_rx_delba(struct ath10k *ar, struct htt_resp *resp)
{
        struct htt_rx_delba *ev = &resp->rx_delba;
        struct ath10k_peer *peer;
        struct ath10k_vif *arvif;
        u16 info0, tid, peer_id;

        info0 = __le16_to_cpu(ev->info0);
        tid = MS(info0, HTT_RX_BA_INFO0_TID);
        peer_id = MS(info0, HTT_RX_BA_INFO0_PEER_ID);

        ath10k_dbg(ar, ATH10K_DBG_HTT,
                   "htt rx delba tid %hu peer_id %hu\n",
                   tid, peer_id);

        spin_lock_bh(&ar->data_lock);
        peer = ath10k_peer_find_by_id(ar, peer_id);
        if (!peer) {
                ath10k_warn(ar, "received addba event for invalid peer_id: %hu\n",
                            peer_id);
                spin_unlock_bh(&ar->data_lock);
                return;
        }

        arvif = ath10k_get_arvif(ar, peer->vdev_id);
        if (!arvif) {
                ath10k_warn(ar, "received addba event for invalid vdev_id: %u\n",
                            peer->vdev_id);
                spin_unlock_bh(&ar->data_lock);
                return;
        }

        ath10k_dbg(ar, ATH10K_DBG_HTT,
                   "htt rx stop rx ba session sta %pM tid %hu\n",
                   peer->addr, tid);

        ieee80211_stop_rx_ba_session_offl(arvif->vif, peer->addr, tid);
        spin_unlock_bh(&ar->data_lock);
}

static int ath10k_htt_rx_extract_amsdu(struct sk_buff_head *list,
                                       struct sk_buff_head *amsdu)
{
        struct sk_buff *msdu;
        struct htt_rx_desc *rxd;

        if (skb_queue_empty(list))
                return -ENOBUFS;

        if (WARN_ON(!skb_queue_empty(amsdu)))
                return -EINVAL;

        while ((msdu = __skb_dequeue(list))) {
                __skb_queue_tail(amsdu, msdu);

                rxd = (void *)msdu->data - sizeof(*rxd);
                if (rxd->msdu_end.common.info0 &
                    __cpu_to_le32(RX_MSDU_END_INFO0_LAST_MSDU))
                        break;
        }

        msdu = skb_peek_tail(amsdu);
        rxd = (void *)msdu->data - sizeof(*rxd);
        if (!(rxd->msdu_end.common.info0 &
              __cpu_to_le32(RX_MSDU_END_INFO0_LAST_MSDU))) {
                skb_queue_splice_init(amsdu, list);
                return -EAGAIN;
        }

        return 0;
}

static void ath10k_htt_rx_h_rx_offload_prot(struct ieee80211_rx_status *status,
                                            struct sk_buff *skb)
{
        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;

        if (!ieee80211_has_protected(hdr->frame_control))
                return;

        /* Offloaded frames are already decrypted but firmware insists they are
         * protected in the 802.11 header. Strip the flag.  Otherwise mac80211
         * will drop the frame.
         */

        hdr->frame_control &= ~__cpu_to_le16(IEEE80211_FCTL_PROTECTED);
        status->flag |= RX_FLAG_DECRYPTED |
                        RX_FLAG_IV_STRIPPED |
                        RX_FLAG_MMIC_STRIPPED;
}

static void ath10k_htt_rx_h_rx_offload(struct ath10k *ar,
                                       struct sk_buff_head *list)
{
        struct ath10k_htt *htt = &ar->htt;
        struct ieee80211_rx_status *status = &htt->rx_status;
        struct htt_rx_offload_msdu *rx;
        struct sk_buff *msdu;
        size_t offset;

        while ((msdu = __skb_dequeue(list))) {
                /* Offloaded frames don't have Rx descriptor. Instead they have
                 * a short meta information header.
                 */

                rx = (void *)msdu->data;

                skb_put(msdu, sizeof(*rx));
                skb_pull(msdu, sizeof(*rx));

                if (skb_tailroom(msdu) < __le16_to_cpu(rx->msdu_len)) {
                        ath10k_warn(ar, "dropping frame: offloaded rx msdu is too long!\n");
                        dev_kfree_skb_any(msdu);
                        continue;
                }

                skb_put(msdu, __le16_to_cpu(rx->msdu_len));

                /* Offloaded rx header length isn't multiple of 2 nor 4 so the
                 * actual payload is unaligned. Align the frame.  Otherwise
                 * mac80211 complains.  This shouldn't reduce performance much
                 * because these offloaded frames are rare.
                 */
                offset = 4 - ((unsigned long)msdu->data & 3);
                skb_put(msdu, offset);
                memmove(msdu->data + offset, msdu->data, msdu->len);
                skb_pull(msdu, offset);

                /* FIXME: The frame is NWifi. Re-construct QoS Control
                 * if possible later.
                 */

                memset(status, 0, sizeof(*status));
                status->flag |= RX_FLAG_NO_SIGNAL_VAL;

                ath10k_htt_rx_h_rx_offload_prot(status, msdu);
                ath10k_htt_rx_h_channel(ar, status, NULL, rx->vdev_id);
                ath10k_process_rx(ar, status, msdu);
        }
}

static void ath10k_htt_rx_in_ord_ind(struct ath10k *ar, struct sk_buff *skb)
{
        struct ath10k_htt *htt = &ar->htt;
        struct htt_resp *resp = (void *)skb->data;
        struct ieee80211_rx_status *status = &htt->rx_status;
        struct sk_buff_head list;
        struct sk_buff_head amsdu;
        u16 peer_id;
        u16 msdu_count;
        u8 vdev_id;
        u8 tid;
        bool offload;
        bool frag;
        int ret;

        lockdep_assert_held(&htt->rx_ring.lock);

        if (htt->rx_confused)
                return;

        skb_pull(skb, sizeof(resp->hdr));
        skb_pull(skb, sizeof(resp->rx_in_ord_ind));

        peer_id = __le16_to_cpu(resp->rx_in_ord_ind.peer_id);
        msdu_count = __le16_to_cpu(resp->rx_in_ord_ind.msdu_count);
        vdev_id = resp->rx_in_ord_ind.vdev_id;
        tid = SM(resp->rx_in_ord_ind.info, HTT_RX_IN_ORD_IND_INFO_TID);
        offload = !!(resp->rx_in_ord_ind.info &
                        HTT_RX_IN_ORD_IND_INFO_OFFLOAD_MASK);
        frag = !!(resp->rx_in_ord_ind.info & HTT_RX_IN_ORD_IND_INFO_FRAG_MASK);

        ath10k_dbg(ar, ATH10K_DBG_HTT,
                   "htt rx in ord vdev %i peer %i tid %i offload %i frag %i msdu count %i\n",
                   vdev_id, peer_id, tid, offload, frag, msdu_count);

        if (skb->len < msdu_count * sizeof(*resp->rx_in_ord_ind.msdu_descs)) {
                ath10k_warn(ar, "dropping invalid in order rx indication\n");
                return;
        }

        /* The event can deliver more than 1 A-MSDU. Each A-MSDU is later
         * extracted and processed.
         */
        __skb_queue_head_init(&list);
        ret = ath10k_htt_rx_pop_paddr_list(htt, &resp->rx_in_ord_ind, &list);
        if (ret < 0) {
                ath10k_warn(ar, "failed to pop paddr list: %d\n", ret);
                htt->rx_confused = true;
                return;
        }

        /* Offloaded frames are very different and need to be handled
         * separately.
         */
        if (offload)
                ath10k_htt_rx_h_rx_offload(ar, &list);

        while (!skb_queue_empty(&list)) {
                __skb_queue_head_init(&amsdu);
                ret = ath10k_htt_rx_extract_amsdu(&list, &amsdu);
                switch (ret) {
                case 0:
                        /* Note: The in-order indication may report interleaved
                         * frames from different PPDUs meaning reported rx rate
                         * to mac80211 isn't accurate/reliable. It's still
                         * better to report something than nothing though. This
                         * should still give an idea about rx rate to the user.
                         */
                        ath10k_htt_rx_h_ppdu(ar, &amsdu, status, vdev_id);
                        ath10k_htt_rx_h_filter(ar, &amsdu, status);
                        ath10k_htt_rx_h_mpdu(ar, &amsdu, status);
                        ath10k_htt_rx_h_deliver(ar, &amsdu, status);
                        break;
                case -EAGAIN:
                        /* fall through */
                default:
                        /* Should not happen. */
                        ath10k_warn(ar, "failed to extract amsdu: %d\n", ret);
                        htt->rx_confused = true;
                        __skb_queue_purge(&list);
                        return;
                }
        }
}

static void ath10k_htt_rx_tx_fetch_resp_id_confirm(struct ath10k *ar,
                                                   const __le32 *resp_ids,
                                                   int num_resp_ids)
{
        int i;
        u32 resp_id;

        ath10k_dbg(ar, ATH10K_DBG_HTT, "htt rx tx fetch confirm num_resp_ids %d\n",
                   num_resp_ids);

        for (i = 0; i < num_resp_ids; i++) {
                resp_id = le32_to_cpu(resp_ids[i]);

                ath10k_dbg(ar, ATH10K_DBG_HTT, "htt rx tx fetch confirm resp_id %u\n",
                           resp_id);

                /* TODO: free resp_id */
        }
}

static void ath10k_htt_rx_tx_fetch_ind(struct ath10k *ar, struct sk_buff *skb)
{
        struct ieee80211_hw *hw = ar->hw;
        struct ieee80211_txq *txq;
        struct htt_resp *resp = (struct htt_resp *)skb->data;
        struct htt_tx_fetch_record *record;
        size_t len;
        size_t max_num_bytes;
        size_t max_num_msdus;
        size_t num_bytes;
        size_t num_msdus;
        const __le32 *resp_ids;
        u16 num_records;
        u16 num_resp_ids;
        u16 peer_id;
        u8 tid;
        int ret;
        int i;

        ath10k_dbg(ar, ATH10K_DBG_HTT, "htt rx tx fetch ind\n");

        len = sizeof(resp->hdr) + sizeof(resp->tx_fetch_ind);
        if (unlikely(skb->len < len)) {
                ath10k_warn(ar, "received corrupted tx_fetch_ind event: buffer too short\n");
                return;
        }

        num_records = le16_to_cpu(resp->tx_fetch_ind.num_records);
        num_resp_ids = le16_to_cpu(resp->tx_fetch_ind.num_resp_ids);

        len += sizeof(resp->tx_fetch_ind.records[0]) * num_records;
        len += sizeof(resp->tx_fetch_ind.resp_ids[0]) * num_resp_ids;

        if (unlikely(skb->len < len)) {
                ath10k_warn(ar, "received corrupted tx_fetch_ind event: too many records/resp_ids\n");
                return;
        }

        ath10k_dbg(ar, ATH10K_DBG_HTT, "htt rx tx fetch ind num records %hu num resps %hu seq %hu\n",
                   num_records, num_resp_ids,
                   le16_to_cpu(resp->tx_fetch_ind.fetch_seq_num));

        if (!ar->htt.tx_q_state.enabled) {
                ath10k_warn(ar, "received unexpected tx_fetch_ind event: not enabled\n");
                return;
        }

        if (ar->htt.tx_q_state.mode == HTT_TX_MODE_SWITCH_PUSH) {
                ath10k_warn(ar, "received unexpected tx_fetch_ind event: in push mode\n");
                return;
        }

        rcu_read_lock();

        for (i = 0; i < num_records; i++) {
                record = &resp->tx_fetch_ind.records[i];
                peer_id = MS(le16_to_cpu(record->info),
                             HTT_TX_FETCH_RECORD_INFO_PEER_ID);
                tid = MS(le16_to_cpu(record->info),
                         HTT_TX_FETCH_RECORD_INFO_TID);
                max_num_msdus = le16_to_cpu(record->num_msdus);
                max_num_bytes = le32_to_cpu(record->num_bytes);

                ath10k_dbg(ar, ATH10K_DBG_HTT, "htt rx tx fetch record %i peer_id %hu tid %hhu msdus %zu bytes %zu\n",
                           i, peer_id, tid, max_num_msdus, max_num_bytes);

                if (unlikely(peer_id >= ar->htt.tx_q_state.num_peers) ||
                    unlikely(tid >= ar->htt.tx_q_state.num_tids)) {
                        ath10k_warn(ar, "received out of range peer_id %hu tid %hhu\n",
                                    peer_id, tid);
                        continue;
                }

                spin_lock_bh(&ar->data_lock);
                txq = ath10k_mac_txq_lookup(ar, peer_id, tid);
                spin_unlock_bh(&ar->data_lock);

                /* It is okay to release the lock and use txq because RCU read
                 * lock is held.
                 */

                if (unlikely(!txq)) {
                        ath10k_warn(ar, "failed to lookup txq for peer_id %hu tid %hhu\n",
                                    peer_id, tid);
                        continue;
                }

                num_msdus = 0;
                num_bytes = 0;

                while (num_msdus < max_num_msdus &&
                       num_bytes < max_num_bytes) {
                        ret = ath10k_mac_tx_push_txq(hw, txq);
                        if (ret < 0)
                                break;

                        num_msdus++;
                        num_bytes += ret;
                }

                record->num_msdus = cpu_to_le16(num_msdus);
                record->num_bytes = cpu_to_le32(num_bytes);

                ath10k_htt_tx_txq_recalc(hw, txq);
        }

        rcu_read_unlock();

        resp_ids = ath10k_htt_get_tx_fetch_ind_resp_ids(&resp->tx_fetch_ind);
        ath10k_htt_rx_tx_fetch_resp_id_confirm(ar, resp_ids, num_resp_ids);

        ret = ath10k_htt_tx_fetch_resp(ar,
                                       resp->tx_fetch_ind.token,
                                       resp->tx_fetch_ind.fetch_seq_num,
                                       resp->tx_fetch_ind.records,
                                       num_records);
        if (unlikely(ret)) {
                ath10k_warn(ar, "failed to submit tx fetch resp for token 0x%08x: %d\n",
                            le32_to_cpu(resp->tx_fetch_ind.token), ret);
                /* FIXME: request fw restart */
        }

        ath10k_htt_tx_txq_sync(ar);
}

static void ath10k_htt_rx_tx_fetch_confirm(struct ath10k *ar,
                                           struct sk_buff *skb)
{
        const struct htt_resp *resp = (void *)skb->data;
        size_t len;
        int num_resp_ids;

        ath10k_dbg(ar, ATH10K_DBG_HTT, "htt rx tx fetch confirm\n");

        len = sizeof(resp->hdr) + sizeof(resp->tx_fetch_confirm);
        if (unlikely(skb->len < len)) {
                ath10k_warn(ar, "received corrupted tx_fetch_confirm event: buffer too short\n");
                return;
        }

        num_resp_ids = le16_to_cpu(resp->tx_fetch_confirm.num_resp_ids);
        len += sizeof(resp->tx_fetch_confirm.resp_ids[0]) * num_resp_ids;

        if (unlikely(skb->len < len)) {
                ath10k_warn(ar, "received corrupted tx_fetch_confirm event: resp_ids buffer overflow\n");
                return;
        }

        ath10k_htt_rx_tx_fetch_resp_id_confirm(ar,
                                               resp->tx_fetch_confirm.resp_ids,
                                               num_resp_ids);
}

static void ath10k_htt_rx_tx_mode_switch_ind(struct ath10k *ar,
                                             struct sk_buff *skb)
{
        const struct htt_resp *resp = (void *)skb->data;
        const struct htt_tx_mode_switch_record *record;
        struct ieee80211_txq *txq;
        struct ath10k_txq *artxq;
        size_t len;
        size_t num_records;
        enum htt_tx_mode_switch_mode mode;
        bool enable;
        u16 info0;
        u16 info1;
        u16 threshold;
        u16 peer_id;
        u8 tid;
        int i;

        ath10k_dbg(ar, ATH10K_DBG_HTT, "htt rx tx mode switch ind\n");

        len = sizeof(resp->hdr) + sizeof(resp->tx_mode_switch_ind);
        if (unlikely(skb->len < len)) {
                ath10k_warn(ar, "received corrupted tx_mode_switch_ind event: buffer too short\n");
                return;
        }

        info0 = le16_to_cpu(resp->tx_mode_switch_ind.info0);
        info1 = le16_to_cpu(resp->tx_mode_switch_ind.info1);

        enable = !!(info0 & HTT_TX_MODE_SWITCH_IND_INFO0_ENABLE);
        num_records = MS(info0, HTT_TX_MODE_SWITCH_IND_INFO1_THRESHOLD);
        mode = MS(info1, HTT_TX_MODE_SWITCH_IND_INFO1_MODE);
        threshold = MS(info1, HTT_TX_MODE_SWITCH_IND_INFO1_THRESHOLD);

        ath10k_dbg(ar, ATH10K_DBG_HTT,
                   "htt rx tx mode switch ind info0 0x%04hx info1 0x%04hx enable %d num records %zd mode %d threshold %hu\n",
                   info0, info1, enable, num_records, mode, threshold);

        len += sizeof(resp->tx_mode_switch_ind.records[0]) * num_records;

        if (unlikely(skb->len < len)) {
                ath10k_warn(ar, "received corrupted tx_mode_switch_mode_ind event: too many records\n");
                return;
        }

        switch (mode) {
        case HTT_TX_MODE_SWITCH_PUSH:
        case HTT_TX_MODE_SWITCH_PUSH_PULL:
                break;
        default:
                ath10k_warn(ar, "received invalid tx_mode_switch_mode_ind mode %d, ignoring\n",
                            mode);
                return;
        }

        if (!enable)
                return;

        ar->htt.tx_q_state.enabled = enable;
        ar->htt.tx_q_state.mode = mode;
        ar->htt.tx_q_state.num_push_allowed = threshold;

        rcu_read_lock();

        for (i = 0; i < num_records; i++) {
                record = &resp->tx_mode_switch_ind.records[i];
                info0 = le16_to_cpu(record->info0);
                peer_id = MS(info0, HTT_TX_MODE_SWITCH_RECORD_INFO0_PEER_ID);
                tid = MS(info0, HTT_TX_MODE_SWITCH_RECORD_INFO0_TID);

                if (unlikely(peer_id >= ar->htt.tx_q_state.num_peers) ||
                    unlikely(tid >= ar->htt.tx_q_state.num_tids)) {
                        ath10k_warn(ar, "received out of range peer_id %hu tid %hhu\n",
                                    peer_id, tid);
                        continue;
                }

                spin_lock_bh(&ar->data_lock);
                txq = ath10k_mac_txq_lookup(ar, peer_id, tid);
                spin_unlock_bh(&ar->data_lock);

                /* It is okay to release the lock and use txq because RCU read
                 * lock is held.
                 */

                if (unlikely(!txq)) {
                        ath10k_warn(ar, "failed to lookup txq for peer_id %hu tid %hhu\n",
                                    peer_id, tid);
                        continue;
                }

                spin_lock_bh(&ar->htt.tx_lock);
                artxq = (void *)txq->drv_priv;
                artxq->num_push_allowed = le16_to_cpu(record->num_max_msdus);
                spin_unlock_bh(&ar->htt.tx_lock);
        }

        rcu_read_unlock();

        ath10k_mac_tx_push_pending(ar);
}

static inline enum nl80211_band phy_mode_to_band(u32 phy_mode)
{
        enum nl80211_band band;

        switch (phy_mode) {
        case MODE_11A:
        case MODE_11NA_HT20:
        case MODE_11NA_HT40:
        case MODE_11AC_VHT20:
        case MODE_11AC_VHT40:
        case MODE_11AC_VHT80:
                band = NL80211_BAND_5GHZ;
                break;
        case MODE_11G:
        case MODE_11B:
        case MODE_11GONLY:
        case MODE_11NG_HT20:
        case MODE_11NG_HT40:
        case MODE_11AC_VHT20_2G:
        case MODE_11AC_VHT40_2G:
        case MODE_11AC_VHT80_2G:
        default:
                band = NL80211_BAND_2GHZ;
        }

        return band;
}

void ath10k_htt_htc_t2h_msg_handler(struct ath10k *ar, struct sk_buff *skb)
{
        bool release;

        release = ath10k_htt_t2h_msg_handler(ar, skb);

        /* Free the indication buffer */
        if (release)
                dev_kfree_skb_any(skb);
}

bool ath10k_htt_t2h_msg_handler(struct ath10k *ar, struct sk_buff *skb)
{
        struct ath10k_htt *htt = &ar->htt;
        struct htt_resp *resp = (struct htt_resp *)skb->data;
        enum htt_t2h_msg_type type;

        /* confirm alignment */
        if (!IS_ALIGNED((unsigned long)skb->data, 4))
                ath10k_warn(ar, "unaligned htt message, expect trouble\n");

        ath10k_dbg(ar, ATH10K_DBG_HTT, "htt rx, msg_type: 0x%0X\n",
                   resp->hdr.msg_type);

        if (resp->hdr.msg_type >= ar->htt.t2h_msg_types_max) {
                ath10k_dbg(ar, ATH10K_DBG_HTT, "htt rx, unsupported msg_type: 0x%0X\n max: 0x%0X",
                           resp->hdr.msg_type, ar->htt.t2h_msg_types_max);
                return true;
        }
        type = ar->htt.t2h_msg_types[resp->hdr.msg_type];

        switch (type) {
        case HTT_T2H_MSG_TYPE_VERSION_CONF: {
                htt->target_version_major = resp->ver_resp.major;
                htt->target_version_minor = resp->ver_resp.minor;
                complete(&htt->target_version_received);
                break;
        }
        case HTT_T2H_MSG_TYPE_RX_IND:
                ath10k_htt_rx_proc_rx_ind(htt, &resp->rx_ind);
                break;
        case HTT_T2H_MSG_TYPE_PEER_MAP: {
                struct htt_peer_map_event ev = {
                        .vdev_id = resp->peer_map.vdev_id,
                        .peer_id = __le16_to_cpu(resp->peer_map.peer_id),
                };
                memcpy(ev.addr, resp->peer_map.addr, sizeof(ev.addr));
                ath10k_peer_map_event(htt, &ev);
                break;
        }
        case HTT_T2H_MSG_TYPE_PEER_UNMAP: {
                struct htt_peer_unmap_event ev = {
                        .peer_id = __le16_to_cpu(resp->peer_unmap.peer_id),
                };
                ath10k_peer_unmap_event(htt, &ev);
                break;
        }
        case HTT_T2H_MSG_TYPE_MGMT_TX_COMPLETION: {
                struct htt_tx_done tx_done = {};
                int status = __le32_to_cpu(resp->mgmt_tx_completion.status);

                tx_done.msdu_id = __le32_to_cpu(resp->mgmt_tx_completion.desc_id);

                switch (status) {
                case HTT_MGMT_TX_STATUS_OK:
                        tx_done.status = HTT_TX_COMPL_STATE_ACK;
                        break;
                case HTT_MGMT_TX_STATUS_RETRY:
                        tx_done.status = HTT_TX_COMPL_STATE_NOACK;
                        break;
                case HTT_MGMT_TX_STATUS_DROP:
                        tx_done.status = HTT_TX_COMPL_STATE_DISCARD;
                        break;
                }

                status = ath10k_txrx_tx_unref(htt, &tx_done);
                if (!status) {
                        spin_lock_bh(&htt->tx_lock);
                        ath10k_htt_tx_mgmt_dec_pending(htt);
                        spin_unlock_bh(&htt->tx_lock);
                }
                ath10k_mac_tx_push_pending(ar);
                break;
        }
        case HTT_T2H_MSG_TYPE_TX_COMPL_IND:
                ath10k_htt_rx_tx_compl_ind(htt->ar, skb);
                tasklet_schedule(&htt->txrx_compl_task);
                break;
        case HTT_T2H_MSG_TYPE_SEC_IND: {
                struct ath10k *ar = htt->ar;
                struct htt_security_indication *ev = &resp->security_indication;

                ath10k_dbg(ar, ATH10K_DBG_HTT,
                           "sec ind peer_id %d unicast %d type %d\n",
                          __le16_to_cpu(ev->peer_id),
                          !!(ev->flags & HTT_SECURITY_IS_UNICAST),
                          MS(ev->flags, HTT_SECURITY_TYPE));
                complete(&ar->install_key_done);
                break;
        }
        case HTT_T2H_MSG_TYPE_RX_FRAG_IND: {
                ath10k_dbg_dump(ar, ATH10K_DBG_HTT_DUMP, NULL, "htt event: ",
                                skb->data, skb->len);
                ath10k_htt_rx_frag_handler(htt);
                break;
        }
        case HTT_T2H_MSG_TYPE_TEST:
                break;
        case HTT_T2H_MSG_TYPE_STATS_CONF:
                trace_ath10k_htt_stats(ar, skb->data, skb->len);
                break;
        case HTT_T2H_MSG_TYPE_TX_INSPECT_IND:
                /* Firmware can return tx frames if it's unable to fully
                 * process them and suspects host may be able to fix it. ath10k
                 * sends all tx frames as already inspected so this shouldn't
                 * happen unless fw has a bug.
                 */
                ath10k_warn(ar, "received an unexpected htt tx inspect event\n");
                break;
        case HTT_T2H_MSG_TYPE_RX_ADDBA:
                ath10k_htt_rx_addba(ar, resp);
                break;
        case HTT_T2H_MSG_TYPE_RX_DELBA:
                ath10k_htt_rx_delba(ar, resp);
                break;
        case HTT_T2H_MSG_TYPE_PKTLOG: {
                struct ath10k_pktlog_hdr *hdr =
                        (struct ath10k_pktlog_hdr *)resp->pktlog_msg.payload;

                trace_ath10k_htt_pktlog(ar, resp->pktlog_msg.payload,
                                        sizeof(*hdr) +
                                        __le16_to_cpu(hdr->size));
                break;
        }
        case HTT_T2H_MSG_TYPE_RX_FLUSH: {
                /* Ignore this event because mac80211 takes care of Rx
                 * aggregation reordering.
                 */
                break;
        }
        case HTT_T2H_MSG_TYPE_RX_IN_ORD_PADDR_IND: {
                skb_queue_tail(&htt->rx_in_ord_compl_q, skb);
                tasklet_schedule(&htt->txrx_compl_task);
                return false;
        }
        case HTT_T2H_MSG_TYPE_TX_CREDIT_UPDATE_IND:
                break;
        case HTT_T2H_MSG_TYPE_CHAN_CHANGE: {
                u32 phymode = __le32_to_cpu(resp->chan_change.phymode);
                u32 freq = __le32_to_cpu(resp->chan_change.freq);

                ar->tgt_oper_chan =
                        __ieee80211_get_channel(ar->hw->wiphy, freq);
                ath10k_dbg(ar, ATH10K_DBG_HTT,
                           "htt chan change freq %u phymode %s\n",
                           freq, ath10k_wmi_phymode_str(phymode));
                break;
        }
        case HTT_T2H_MSG_TYPE_AGGR_CONF:
                break;
        case HTT_T2H_MSG_TYPE_TX_FETCH_IND: {
                struct sk_buff *tx_fetch_ind = skb_copy(skb, GFP_ATOMIC);

                if (!tx_fetch_ind) {
                        ath10k_warn(ar, "failed to copy htt tx fetch ind\n");
                        break;
                }
                skb_queue_tail(&htt->tx_fetch_ind_q, tx_fetch_ind);
                tasklet_schedule(&htt->txrx_compl_task);
                break;
        }
        case HTT_T2H_MSG_TYPE_TX_FETCH_CONFIRM:
                ath10k_htt_rx_tx_fetch_confirm(ar, skb);
                break;
        case HTT_T2H_MSG_TYPE_TX_MODE_SWITCH_IND:
                ath10k_htt_rx_tx_mode_switch_ind(ar, skb);
                break;
        case HTT_T2H_MSG_TYPE_EN_STATS:
        default:
                ath10k_warn(ar, "htt event (%d) not handled\n",
                            resp->hdr.msg_type);
                ath10k_dbg_dump(ar, ATH10K_DBG_HTT_DUMP, NULL, "htt event: ",
                                skb->data, skb->len);
                break;
        };
        return true;
}
EXPORT_SYMBOL(ath10k_htt_t2h_msg_handler);

void ath10k_htt_rx_pktlog_completion_handler(struct ath10k *ar,
                                             struct sk_buff *skb)
{
        trace_ath10k_htt_pktlog(ar, skb->data, skb->len);
        dev_kfree_skb_any(skb);
}
EXPORT_SYMBOL(ath10k_htt_rx_pktlog_completion_handler);

static void ath10k_htt_txrx_compl_task(unsigned long ptr)
{
        struct ath10k_htt *htt = (struct ath10k_htt *)ptr;
        struct ath10k *ar = htt->ar;
        struct htt_tx_done tx_done = {};
        struct sk_buff_head rx_ind_q;
        struct sk_buff_head tx_ind_q;
        struct sk_buff *skb;
        unsigned long flags;
        int num_mpdus;

        __skb_queue_head_init(&rx_ind_q);
        __skb_queue_head_init(&tx_ind_q);

        spin_lock_irqsave(&htt->rx_in_ord_compl_q.lock, flags);
        skb_queue_splice_init(&htt->rx_in_ord_compl_q, &rx_ind_q);
        spin_unlock_irqrestore(&htt->rx_in_ord_compl_q.lock, flags);

        spin_lock_irqsave(&htt->tx_fetch_ind_q.lock, flags);
        skb_queue_splice_init(&htt->tx_fetch_ind_q, &tx_ind_q);
        spin_unlock_irqrestore(&htt->tx_fetch_ind_q.lock, flags);

        /* kfifo_get: called only within txrx_tasklet so it's neatly serialized.
         * From kfifo_get() documentation:
         *  Note that with only one concurrent reader and one concurrent writer,
         *  you don't need extra locking to use these macro.
         */
        while (kfifo_get(&htt->txdone_fifo, &tx_done))
                ath10k_txrx_tx_unref(htt, &tx_done);

        while ((skb = __skb_dequeue(&tx_ind_q))) {
                ath10k_htt_rx_tx_fetch_ind(ar, skb);
                dev_kfree_skb_any(skb);
        }

        ath10k_mac_tx_push_pending(ar);

        num_mpdus = atomic_read(&htt->num_mpdus_ready);

        while (num_mpdus) {
                if (ath10k_htt_rx_handle_amsdu(htt))
                        break;

                num_mpdus--;
                atomic_dec(&htt->num_mpdus_ready);
        }

        while ((skb = __skb_dequeue(&rx_ind_q))) {
                spin_lock_bh(&htt->rx_ring.lock);
                ath10k_htt_rx_in_ord_ind(ar, skb);
                spin_unlock_bh(&htt->rx_ring.lock);
                dev_kfree_skb_any(skb);
        }

        ath10k_htt_rx_msdu_buff_replenish(htt);
}