/*
 * Copyright (c) 2007-2011 Atheros Communications Inc.
 * Copyright (c) 2011-2012 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 "hif.h"
#include "debug.h"
#include "hif-ops.h"
#include "trace.h"

#include <linux/unaligned.h>

#define CALC_TXRX_PADDED_LEN(dev, len)  (__ALIGN_MASK((len), (dev)->block_mask))

static void ath6kl_htc_mbox_cleanup(struct htc_target *target);
static void ath6kl_htc_mbox_stop(struct htc_target *target);
static int ath6kl_htc_mbox_add_rxbuf_multiple(struct htc_target *target,
                                              struct list_head *pkt_queue);
static void ath6kl_htc_set_credit_dist(struct htc_target *target,
                                       struct ath6kl_htc_credit_info *cred_info,
                                       u16 svc_pri_order[], int len);

/* threshold to re-enable Tx bundling for an AC*/
#define TX_RESUME_BUNDLE_THRESHOLD      1500

/* Functions for Tx credit handling */
static void ath6kl_credit_deposit(struct ath6kl_htc_credit_info *cred_info,
                                  struct htc_endpoint_credit_dist *ep_dist,
                                  int credits)
{
        ath6kl_dbg(ATH6KL_DBG_CREDIT, "credit deposit ep %d credits %d\n",
                   ep_dist->endpoint, credits);

        ep_dist->credits += credits;
        ep_dist->cred_assngd += credits;
        cred_info->cur_free_credits -= credits;
}

static void ath6kl_credit_init(struct ath6kl_htc_credit_info *cred_info,
                               struct list_head *ep_list,
                               int tot_credits)
{
        struct htc_endpoint_credit_dist *cur_ep_dist;
        int count;

        ath6kl_dbg(ATH6KL_DBG_CREDIT, "credit init total %d\n", tot_credits);

        cred_info->cur_free_credits = tot_credits;
        cred_info->total_avail_credits = tot_credits;

        list_for_each_entry(cur_ep_dist, ep_list, list) {
                if (cur_ep_dist->endpoint == ENDPOINT_0)
                        continue;

                cur_ep_dist->cred_min = cur_ep_dist->cred_per_msg;

                if (tot_credits > 4) {
                        if ((cur_ep_dist->svc_id == WMI_DATA_BK_SVC) ||
                            (cur_ep_dist->svc_id == WMI_DATA_BE_SVC)) {
                                ath6kl_credit_deposit(cred_info,
                                                      cur_ep_dist,
                                                      cur_ep_dist->cred_min);
                                cur_ep_dist->dist_flags |= HTC_EP_ACTIVE;
                        }
                }

                if (cur_ep_dist->svc_id == WMI_CONTROL_SVC) {
                        ath6kl_credit_deposit(cred_info, cur_ep_dist,
                                              cur_ep_dist->cred_min);
                        /*
                         * Control service is always marked active, it
                         * never goes inactive EVER.
                         */
                        cur_ep_dist->dist_flags |= HTC_EP_ACTIVE;
                }

                /*
                 * Streams have to be created (explicit | implicit) for all
                 * kinds of traffic. BE endpoints are also inactive in the
                 * beginning. When BE traffic starts it creates implicit
                 * streams that redistributes credits.
                 *
                 * Note: all other endpoints have minimums set but are
                 * initially given NO credits. credits will be distributed
                 * as traffic activity demands
                 */
        }

        /*
         * For ath6kl_credit_seek function,
         * it use list_for_each_entry_reverse to walk around the whole ep list.
         * Therefore assign this lowestpri_ep_dist after walk around the ep_list
         */
        cred_info->lowestpri_ep_dist = cur_ep_dist->list;

        WARN_ON(cred_info->cur_free_credits <= 0);

        list_for_each_entry(cur_ep_dist, ep_list, list) {
                if (cur_ep_dist->endpoint == ENDPOINT_0)
                        continue;

                if (cur_ep_dist->svc_id == WMI_CONTROL_SVC) {
                        cur_ep_dist->cred_norm = cur_ep_dist->cred_per_msg;
                } else {
                        /*
                         * For the remaining data endpoints, we assume that
                         * each cred_per_msg are the same. We use a simple
                         * calculation here, we take the remaining credits
                         * and determine how many max messages this can
                         * cover and then set each endpoint's normal value
                         * equal to 3/4 this amount.
                         */
                        count = (cred_info->cur_free_credits /
                                 cur_ep_dist->cred_per_msg)
                                * cur_ep_dist->cred_per_msg;
                        count = (count * 3) >> 2;
                        count = max(count, cur_ep_dist->cred_per_msg);
                        cur_ep_dist->cred_norm = count;
                }

                ath6kl_dbg(ATH6KL_DBG_CREDIT,
                           "credit ep %d svc_id %d credits %d per_msg %d norm %d min %d\n",
                           cur_ep_dist->endpoint,
                           cur_ep_dist->svc_id,
                           cur_ep_dist->credits,
                           cur_ep_dist->cred_per_msg,
                           cur_ep_dist->cred_norm,
                           cur_ep_dist->cred_min);
        }
}

/* initialize and setup credit distribution */
static int ath6kl_htc_mbox_credit_setup(struct htc_target *htc_target,
                               struct ath6kl_htc_credit_info *cred_info)
{
        u16 servicepriority[5];

        memset(cred_info, 0, sizeof(struct ath6kl_htc_credit_info));

        servicepriority[0] = WMI_CONTROL_SVC;  /* highest */
        servicepriority[1] = WMI_DATA_VO_SVC;
        servicepriority[2] = WMI_DATA_VI_SVC;
        servicepriority[3] = WMI_DATA_BE_SVC;
        servicepriority[4] = WMI_DATA_BK_SVC; /* lowest */

        /* set priority list */
        ath6kl_htc_set_credit_dist(htc_target, cred_info, servicepriority, 5);

        return 0;
}

/* reduce an ep's credits back to a set limit */
static void ath6kl_credit_reduce(struct ath6kl_htc_credit_info *cred_info,
                                 struct htc_endpoint_credit_dist *ep_dist,
                                 int limit)
{
        int credits;

        ath6kl_dbg(ATH6KL_DBG_CREDIT, "credit reduce ep %d limit %d\n",
                   ep_dist->endpoint, limit);

        ep_dist->cred_assngd = limit;

        if (ep_dist->credits <= limit)
                return;

        credits = ep_dist->credits - limit;
        ep_dist->credits -= credits;
        cred_info->cur_free_credits += credits;
}

static void ath6kl_credit_update(struct ath6kl_htc_credit_info *cred_info,
                                 struct list_head *epdist_list)
{
        struct htc_endpoint_credit_dist *cur_list;

        list_for_each_entry(cur_list, epdist_list, list) {
                if (cur_list->endpoint == ENDPOINT_0)
                        continue;

                if (cur_list->cred_to_dist > 0) {
                        cur_list->credits += cur_list->cred_to_dist;
                        cur_list->cred_to_dist = 0;

                        if (cur_list->credits > cur_list->cred_assngd)
                                ath6kl_credit_reduce(cred_info,
                                                     cur_list,
                                                     cur_list->cred_assngd);

                        if (cur_list->credits > cur_list->cred_norm)
                                ath6kl_credit_reduce(cred_info, cur_list,
                                                     cur_list->cred_norm);

                        if (!(cur_list->dist_flags & HTC_EP_ACTIVE)) {
                                if (cur_list->txq_depth == 0)
                                        ath6kl_credit_reduce(cred_info,
                                                             cur_list, 0);
                        }
                }
        }
}

/*
 * HTC has an endpoint that needs credits, ep_dist is the endpoint in
 * question.
 */
static void ath6kl_credit_seek(struct ath6kl_htc_credit_info *cred_info,
                                struct htc_endpoint_credit_dist *ep_dist)
{
        struct htc_endpoint_credit_dist *curdist_list;
        int credits = 0;
        int need;

        if (ep_dist->svc_id == WMI_CONTROL_SVC)
                goto out;

        if ((ep_dist->svc_id == WMI_DATA_VI_SVC) ||
            (ep_dist->svc_id == WMI_DATA_VO_SVC))
                if ((ep_dist->cred_assngd >= ep_dist->cred_norm))
                        goto out;

        /*
         * For all other services, we follow a simple algorithm of:
         *
         * 1. checking the free pool for credits
         * 2. checking lower priority endpoints for credits to take
         */

        credits = min(cred_info->cur_free_credits, ep_dist->seek_cred);

        if (credits >= ep_dist->seek_cred)
                goto out;

        /*
         * We don't have enough in the free pool, try taking away from
         * lower priority services The rule for taking away credits:
         *
         *   1. Only take from lower priority endpoints
         *   2. Only take what is allocated above the minimum (never
         *      starve an endpoint completely)
         *   3. Only take what you need.
         */

        list_for_each_entry_reverse(curdist_list,
                                    &cred_info->lowestpri_ep_dist,
                                    list) {
                if (curdist_list == ep_dist)
                        break;

                need = ep_dist->seek_cred - cred_info->cur_free_credits;

                if ((curdist_list->cred_assngd - need) >=
                     curdist_list->cred_min) {
                        /*
                         * The current one has been allocated more than
                         * it's minimum and it has enough credits assigned
                         * above it's minimum to fulfill our need try to
                         * take away just enough to fulfill our need.
                         */
                        ath6kl_credit_reduce(cred_info, curdist_list,
                                             curdist_list->cred_assngd - need);

                        if (cred_info->cur_free_credits >=
                            ep_dist->seek_cred)
                                break;
                }

                if (curdist_list->endpoint == ENDPOINT_0)
                        break;
        }

        credits = min(cred_info->cur_free_credits, ep_dist->seek_cred);

out:
        /* did we find some credits? */
        if (credits)
                ath6kl_credit_deposit(cred_info, ep_dist, credits);

        ep_dist->seek_cred = 0;
}

/* redistribute credits based on activity change */
static void ath6kl_credit_redistribute(struct ath6kl_htc_credit_info *info,
                                       struct list_head *ep_dist_list)
{
        struct htc_endpoint_credit_dist *curdist_list;

        list_for_each_entry(curdist_list, ep_dist_list, list) {
                if (curdist_list->endpoint == ENDPOINT_0)
                        continue;

                if ((curdist_list->svc_id == WMI_DATA_BK_SVC)  ||
                    (curdist_list->svc_id == WMI_DATA_BE_SVC))
                        curdist_list->dist_flags |= HTC_EP_ACTIVE;

                if ((curdist_list->svc_id != WMI_CONTROL_SVC) &&
                    !(curdist_list->dist_flags & HTC_EP_ACTIVE)) {
                        if (curdist_list->txq_depth == 0)
                                ath6kl_credit_reduce(info, curdist_list, 0);
                        else
                                ath6kl_credit_reduce(info,
                                                     curdist_list,
                                                     curdist_list->cred_min);
                }
        }
}

/*
 *
 * This function is invoked whenever endpoints require credit
 * distributions. A lock is held while this function is invoked, this
 * function shall NOT block. The ep_dist_list is a list of distribution
 * structures in prioritized order as defined by the call to the
 * htc_set_credit_dist() api.
 */
static void ath6kl_credit_distribute(struct ath6kl_htc_credit_info *cred_info,
                                     struct list_head *ep_dist_list,
                              enum htc_credit_dist_reason reason)
{
        switch (reason) {
        case HTC_CREDIT_DIST_SEND_COMPLETE:
                ath6kl_credit_update(cred_info, ep_dist_list);
                break;
        case HTC_CREDIT_DIST_ACTIVITY_CHANGE:
                ath6kl_credit_redistribute(cred_info, ep_dist_list);
                break;
        default:
                break;
        }

        WARN_ON(cred_info->cur_free_credits > cred_info->total_avail_credits);
        WARN_ON(cred_info->cur_free_credits < 0);
}

static void ath6kl_htc_tx_buf_align(u8 **buf, unsigned long len)
{
        u8 *align_addr;

        if (!IS_ALIGNED((unsigned long) *buf, 4)) {
                align_addr = PTR_ALIGN(*buf - 4, 4);
                memmove(align_addr, *buf, len);
                *buf = align_addr;
        }
}

static void ath6kl_htc_tx_prep_pkt(struct htc_packet *packet, u8 flags,
                                   int ctrl0, int ctrl1)
{
        struct htc_frame_hdr *hdr;

        packet->buf -= HTC_HDR_LENGTH;
        hdr =  (struct htc_frame_hdr *)packet->buf;

        put_unaligned_le16(packet->act_len, &hdr->payld_len);
        hdr->flags = flags;
        hdr->eid = packet->endpoint;
        hdr->ctrl[0] = ctrl0;
        hdr->ctrl[1] = ctrl1;
}

static void htc_reclaim_txctrl_buf(struct htc_target *target,
                                   struct htc_packet *pkt)
{
        spin_lock_bh(&target->htc_lock);
        list_add_tail(&pkt->list, &target->free_ctrl_txbuf);
        spin_unlock_bh(&target->htc_lock);
}

static struct htc_packet *htc_get_control_buf(struct htc_target *target,
                                              bool tx)
{
        struct htc_packet *packet = NULL;
        struct list_head *buf_list;

        buf_list = tx ? &target->free_ctrl_txbuf : &target->free_ctrl_rxbuf;

        spin_lock_bh(&target->htc_lock);

        if (list_empty(buf_list)) {
                spin_unlock_bh(&target->htc_lock);
                return NULL;
        }

        packet = list_first_entry(buf_list, struct htc_packet, list);
        list_del(&packet->list);
        spin_unlock_bh(&target->htc_lock);

        if (tx)
                packet->buf = packet->buf_start + HTC_HDR_LENGTH;

        return packet;
}

static void htc_tx_comp_update(struct htc_target *target,
                               struct htc_endpoint *endpoint,
                               struct htc_packet *packet)
{
        packet->completion = NULL;
        packet->buf += HTC_HDR_LENGTH;

        if (!packet->status)
                return;

        ath6kl_err("req failed (status:%d, ep:%d, len:%d creds:%d)\n",
                   packet->status, packet->endpoint, packet->act_len,
                   packet->info.tx.cred_used);

        /* on failure to submit, reclaim credits for this packet */
        spin_lock_bh(&target->tx_lock);
        endpoint->cred_dist.cred_to_dist +=
                                packet->info.tx.cred_used;
        endpoint->cred_dist.txq_depth = get_queue_depth(&endpoint->txq);

        ath6kl_dbg(ATH6KL_DBG_HTC, "htc tx ctxt 0x%p dist 0x%p\n",
                   target->credit_info, &target->cred_dist_list);

        ath6kl_credit_distribute(target->credit_info,
                                 &target->cred_dist_list,
                                 HTC_CREDIT_DIST_SEND_COMPLETE);

        spin_unlock_bh(&target->tx_lock);
}

static void htc_tx_complete(struct htc_endpoint *endpoint,
                            struct list_head *txq)
{
        if (list_empty(txq))
                return;

        ath6kl_dbg(ATH6KL_DBG_HTC,
                   "htc tx complete ep %d pkts %d\n",
                   endpoint->eid, get_queue_depth(txq));

        ath6kl_tx_complete(endpoint->target, txq);
}

static void htc_tx_comp_handler(struct htc_target *target,
                                struct htc_packet *packet)
{
        struct htc_endpoint *endpoint = &target->endpoint[packet->endpoint];
        struct list_head container;

        ath6kl_dbg(ATH6KL_DBG_HTC, "htc tx complete seqno %d\n",
                   packet->info.tx.seqno);

        htc_tx_comp_update(target, endpoint, packet);
        INIT_LIST_HEAD(&container);
        list_add_tail(&packet->list, &container);
        /* do completion */
        htc_tx_complete(endpoint, &container);
}

static void htc_async_tx_scat_complete(struct htc_target *target,
                                       struct hif_scatter_req *scat_req)
{
        struct htc_endpoint *endpoint;
        struct htc_packet *packet;
        struct list_head tx_compq;
        int i;

        INIT_LIST_HEAD(&tx_compq);

        ath6kl_dbg(ATH6KL_DBG_HTC,
                   "htc tx scat complete len %d entries %d\n",
                   scat_req->len, scat_req->scat_entries);

        if (scat_req->status)
                ath6kl_err("send scatter req failed: %d\n", scat_req->status);

        packet = scat_req->scat_list[0].packet;
        endpoint = &target->endpoint[packet->endpoint];

        /* walk through the scatter list and process */
        for (i = 0; i < scat_req->scat_entries; i++) {
                packet = scat_req->scat_list[i].packet;
                if (!packet) {
                        WARN_ON(1);
                        return;
                }

                packet->status = scat_req->status;
                htc_tx_comp_update(target, endpoint, packet);
                list_add_tail(&packet->list, &tx_compq);
        }

        /* free scatter request */
        hif_scatter_req_add(target->dev->ar, scat_req);

        /* complete all packets */
        htc_tx_complete(endpoint, &tx_compq);
}

static int ath6kl_htc_tx_issue(struct htc_target *target,
                               struct htc_packet *packet)
{
        int status;
        bool sync = false;
        u32 padded_len, send_len;

        if (!packet->completion)
                sync = true;

        send_len = packet->act_len + HTC_HDR_LENGTH;

        padded_len = CALC_TXRX_PADDED_LEN(target, send_len);

        ath6kl_dbg(ATH6KL_DBG_HTC,
                   "htc tx issue len %d seqno %d padded_len %d mbox 0x%X %s\n",
                   send_len, packet->info.tx.seqno, padded_len,
                   target->dev->ar->mbox_info.htc_addr,
                   sync ? "sync" : "async");

        if (sync) {
                status = hif_read_write_sync(target->dev->ar,
                                target->dev->ar->mbox_info.htc_addr,
                                 packet->buf, padded_len,
                                 HIF_WR_SYNC_BLOCK_INC);

                packet->status = status;
                packet->buf += HTC_HDR_LENGTH;
        } else
                status = hif_write_async(target->dev->ar,
                                target->dev->ar->mbox_info.htc_addr,
                                packet->buf, padded_len,
                                HIF_WR_ASYNC_BLOCK_INC, packet);

        trace_ath6kl_htc_tx(status, packet->endpoint, packet->buf, send_len);

        return status;
}

static int htc_check_credits(struct htc_target *target,
                             struct htc_endpoint *ep, u8 *flags,
                             enum htc_endpoint_id eid, unsigned int len,
                             int *req_cred)
{
        *req_cred = (len > target->tgt_cred_sz) ?
                     DIV_ROUND_UP(len, target->tgt_cred_sz) : 1;

        ath6kl_dbg(ATH6KL_DBG_CREDIT, "credit check need %d got %d\n",
                   *req_cred, ep->cred_dist.credits);

        if (ep->cred_dist.credits < *req_cred) {
                if (eid == ENDPOINT_0)
                        return -EINVAL;

                /* Seek more credits */
                ep->cred_dist.seek_cred = *req_cred - ep->cred_dist.credits;

                ath6kl_credit_seek(target->credit_info, &ep->cred_dist);

                ep->cred_dist.seek_cred = 0;

                if (ep->cred_dist.credits < *req_cred) {
                        ath6kl_dbg(ATH6KL_DBG_CREDIT,
                                   "credit not found for ep %d\n",
                                   eid);
                        return -EINVAL;
                }
        }

        ep->cred_dist.credits -= *req_cred;
        ep->ep_st.cred_cosumd += *req_cred;

         /* When we are getting low on credits, ask for more */
        if (ep->cred_dist.credits < ep->cred_dist.cred_per_msg) {
                ep->cred_dist.seek_cred =
                ep->cred_dist.cred_per_msg - ep->cred_dist.credits;

                ath6kl_credit_seek(target->credit_info, &ep->cred_dist);

                /* see if we were successful in getting more */
                if (ep->cred_dist.credits < ep->cred_dist.cred_per_msg) {
                        /* tell the target we need credits ASAP! */
                        *flags |= HTC_FLAGS_NEED_CREDIT_UPDATE;
                        ep->ep_st.cred_low_indicate += 1;
                        ath6kl_dbg(ATH6KL_DBG_CREDIT,
                                   "credit we need credits asap\n");
                }
        }

        return 0;
}

static void ath6kl_htc_tx_pkts_get(struct htc_target *target,
                                   struct htc_endpoint *endpoint,
                                   struct list_head *queue)
{
        int req_cred;
        u8 flags;
        struct htc_packet *packet;
        unsigned int len;

        while (true) {
                flags = 0;

                if (list_empty(&endpoint->txq))
                        break;
                packet = list_first_entry(&endpoint->txq, struct htc_packet,
                                          list);

                ath6kl_dbg(ATH6KL_DBG_HTC,
                           "htc tx got packet 0x%p queue depth %d\n",
                           packet, get_queue_depth(&endpoint->txq));

                len = CALC_TXRX_PADDED_LEN(target,
                                           packet->act_len + HTC_HDR_LENGTH);

                if (htc_check_credits(target, endpoint, &flags,
                                      packet->endpoint, len, &req_cred))
                        break;

                /* now we can fully move onto caller's queue */
                packet = list_first_entry(&endpoint->txq, struct htc_packet,
                                          list);
                list_move_tail(&packet->list, queue);

                /* save the number of credits this packet consumed */
                packet->info.tx.cred_used = req_cred;

                /* all TX packets are handled asynchronously */
                packet->completion = htc_tx_comp_handler;
                packet->context = target;
                endpoint->ep_st.tx_issued += 1;

                /* save send flags */
                packet->info.tx.flags = flags;
                packet->info.tx.seqno = endpoint->seqno;
                endpoint->seqno++;
        }
}

/* See if the padded tx length falls on a credit boundary */
static int htc_get_credit_padding(unsigned int cred_sz, int *len,
                                  struct htc_endpoint *ep)
{
        int rem_cred, cred_pad;

        rem_cred = *len % cred_sz;

        /* No padding needed */
        if  (!rem_cred)
                return 0;

        if (!(ep->conn_flags & HTC_FLGS_TX_BNDL_PAD_EN))
                return -1;

        /*
         * The transfer consumes a "partial" credit, this
         * packet cannot be bundled unless we add
         * additional "dummy" padding (max 255 bytes) to
         * consume the entire credit.
         */
        cred_pad = *len < cred_sz ? (cred_sz - *len) : rem_cred;

        if ((cred_pad > 0) && (cred_pad <= 255))
                *len += cred_pad;
        else
                /* The amount of padding is too large, send as non-bundled */
                return -1;

        return cred_pad;
}

static int ath6kl_htc_tx_setup_scat_list(struct htc_target *target,
                                         struct htc_endpoint *endpoint,
                                         struct hif_scatter_req *scat_req,
                                         int n_scat,
                                         struct list_head *queue)
{
        struct htc_packet *packet;
        int i, len, rem_scat, cred_pad;
        int status = 0;
        u8 flags;

        rem_scat = target->max_tx_bndl_sz;

        for (i = 0; i < n_scat; i++) {
                scat_req->scat_list[i].packet = NULL;

                if (list_empty(queue))
                        break;

                packet = list_first_entry(queue, struct htc_packet, list);
                len = CALC_TXRX_PADDED_LEN(target,
                                           packet->act_len + HTC_HDR_LENGTH);

                cred_pad = htc_get_credit_padding(target->tgt_cred_sz,
                                                  &len, endpoint);
                if (cred_pad < 0 || rem_scat < len) {
                        status = -ENOSPC;
                        break;
                }

                rem_scat -= len;
                /* now remove it from the queue */
                list_del(&packet->list);

                scat_req->scat_list[i].packet = packet;
                /* prepare packet and flag message as part of a send bundle */
                flags = packet->info.tx.flags | HTC_FLAGS_SEND_BUNDLE;
                ath6kl_htc_tx_prep_pkt(packet, flags,
                                       cred_pad, packet->info.tx.seqno);
                /* Make sure the buffer is 4-byte aligned */
                ath6kl_htc_tx_buf_align(&packet->buf,
                                        packet->act_len + HTC_HDR_LENGTH);
                scat_req->scat_list[i].buf = packet->buf;
                scat_req->scat_list[i].len = len;

                scat_req->len += len;
                scat_req->scat_entries++;
                ath6kl_dbg(ATH6KL_DBG_HTC,
                           "htc tx adding (%d) pkt 0x%p seqno %d len %d remaining %d\n",
                           i, packet, packet->info.tx.seqno, len, rem_scat);
        }

        /* Roll back scatter setup in case of any failure */
        if (scat_req->scat_entries < HTC_MIN_HTC_MSGS_TO_BUNDLE) {
                for (i = scat_req->scat_entries - 1; i >= 0; i--) {
                        packet = scat_req->scat_list[i].packet;
                        if (packet) {
                                packet->buf += HTC_HDR_LENGTH;
                                list_add(&packet->list, queue);
                        }
                }
                return -EAGAIN;
        }

        return status;
}

/*
 * Drain a queue and send as bundles this function may return without fully
 * draining the queue when
 *
 *    1. scatter resources are exhausted
 *    2. a message that will consume a partial credit will stop the
 *    bundling process early
 *    3. we drop below the minimum number of messages for a bundle
 */
static void ath6kl_htc_tx_bundle(struct htc_endpoint *endpoint,
                                 struct list_head *queue,
                                 int *sent_bundle, int *n_bundle_pkts)
{
        struct htc_target *target = endpoint->target;
        struct hif_scatter_req *scat_req = NULL;
        int n_scat, n_sent_bundle = 0, tot_pkts_bundle = 0, i;
        struct htc_packet *packet;
        int status;
        u32 txb_mask;
        u8 ac = WMM_NUM_AC;

        if ((HTC_CTRL_RSVD_SVC != endpoint->svc_id) &&
            (WMI_CONTROL_SVC != endpoint->svc_id))
                ac = target->dev->ar->ep2ac_map[endpoint->eid];

        while (true) {
                status = 0;
                n_scat = get_queue_depth(queue);
                n_scat = min(n_scat, target->msg_per_bndl_max);

                if (n_scat < HTC_MIN_HTC_MSGS_TO_BUNDLE)
                        /* not enough to bundle */
                        break;

                scat_req = hif_scatter_req_get(target->dev->ar);

                if (!scat_req) {
                        /* no scatter resources  */
                        ath6kl_dbg(ATH6KL_DBG_HTC,
                                   "htc tx no more scatter resources\n");
                        break;
                }

                if ((ac < WMM_NUM_AC) && (ac != WMM_AC_BK)) {
                        if (WMM_AC_BE == ac)
                                /*
                                 * BE, BK have priorities and bit
                                 * positions reversed
                                 */
                                txb_mask = (1 << WMM_AC_BK);
                        else
                                /*
                                 * any AC with priority lower than
                                 * itself
                                 */
                                txb_mask = ((1 << ac) - 1);

                        /*
                         * when the scatter request resources drop below a
                         * certain threshold, disable Tx bundling for all
                         * AC's with priority lower than the current requesting
                         * AC. Otherwise re-enable Tx bundling for them
                         */
                        if (scat_req->scat_q_depth < ATH6KL_SCATTER_REQS)
                                target->tx_bndl_mask &= ~txb_mask;
                        else
                                target->tx_bndl_mask |= txb_mask;
                }

                ath6kl_dbg(ATH6KL_DBG_HTC, "htc tx pkts to scatter: %d\n",
                           n_scat);

                scat_req->len = 0;
                scat_req->scat_entries = 0;

                status = ath6kl_htc_tx_setup_scat_list(target, endpoint,
                                                       scat_req, n_scat,
                                                       queue);
                if (status == -EAGAIN) {
                        hif_scatter_req_add(target->dev->ar, scat_req);
                        break;
                }

                /* send path is always asynchronous */
                scat_req->complete = htc_async_tx_scat_complete;
                n_sent_bundle++;
                tot_pkts_bundle += scat_req->scat_entries;

                ath6kl_dbg(ATH6KL_DBG_HTC,
                           "htc tx scatter bytes %d entries %d\n",
                           scat_req->len, scat_req->scat_entries);

                for (i = 0; i < scat_req->scat_entries; i++) {
                        packet = scat_req->scat_list[i].packet;
                        trace_ath6kl_htc_tx(packet->status, packet->endpoint,
                                            packet->buf, packet->act_len);
                }

                ath6kl_hif_submit_scat_req(target->dev, scat_req, false);

                if (status)
                        break;
        }

        *sent_bundle = n_sent_bundle;
        *n_bundle_pkts = tot_pkts_bundle;
        ath6kl_dbg(ATH6KL_DBG_HTC, "htc tx bundle sent %d pkts\n",
                   n_sent_bundle);

        return;
}

static void ath6kl_htc_tx_from_queue(struct htc_target *target,
                                     struct htc_endpoint *endpoint)
{
        struct list_head txq;
        struct htc_packet *packet;
        int bundle_sent;
        int n_pkts_bundle;
        u8 ac = WMM_NUM_AC;
        int status;

        spin_lock_bh(&target->tx_lock);

        endpoint->tx_proc_cnt++;
        if (endpoint->tx_proc_cnt > 1) {
                endpoint->tx_proc_cnt--;
                spin_unlock_bh(&target->tx_lock);
                ath6kl_dbg(ATH6KL_DBG_HTC, "htc tx busy\n");
                return;
        }

        /*
         * drain the endpoint TX queue for transmission as long
         * as we have enough credits.
         */
        INIT_LIST_HEAD(&txq);

        if ((HTC_CTRL_RSVD_SVC != endpoint->svc_id) &&
            (WMI_CONTROL_SVC != endpoint->svc_id))
                ac = target->dev->ar->ep2ac_map[endpoint->eid];

        while (true) {
                if (list_empty(&endpoint->txq))
                        break;

                ath6kl_htc_tx_pkts_get(target, endpoint, &txq);

                if (list_empty(&txq))
                        break;

                spin_unlock_bh(&target->tx_lock);

                bundle_sent = 0;
                n_pkts_bundle = 0;

                while (true) {
                        /* try to send a bundle on each pass */
                        if ((target->tx_bndl_mask) &&
                            (get_queue_depth(&txq) >=
                            HTC_MIN_HTC_MSGS_TO_BUNDLE)) {
                                int temp1 = 0, temp2 = 0;

                                /* check if bundling is enabled for an AC */
                                if (target->tx_bndl_mask & (1 << ac)) {
                                        ath6kl_htc_tx_bundle(endpoint, &txq,
                                                             &temp1, &temp2);
                                        bundle_sent += temp1;
                                        n_pkts_bundle += temp2;
                                }
                        }

                        if (list_empty(&txq))
                                break;

                        packet = list_first_entry(&txq, struct htc_packet,
                                                  list);
                        list_del(&packet->list);

                        ath6kl_htc_tx_prep_pkt(packet, packet->info.tx.flags,
                                               0, packet->info.tx.seqno);
                        status = ath6kl_htc_tx_issue(target, packet);

                        if (status) {
                                packet->status = status;
                                packet->completion(packet->context, packet);
                        }
                }

                spin_lock_bh(&target->tx_lock);

                endpoint->ep_st.tx_bundles += bundle_sent;
                endpoint->ep_st.tx_pkt_bundled += n_pkts_bundle;

                /*
                 * if an AC has bundling disabled and no tx bundling
                 * has occurred continuously for a certain number of TX,
                 * enable tx bundling for this AC
                 */
                if (!bundle_sent) {
                        if (!(target->tx_bndl_mask & (1 << ac)) &&
                            (ac < WMM_NUM_AC)) {
                                if (++target->ac_tx_count[ac] >=
                                        TX_RESUME_BUNDLE_THRESHOLD) {
                                        target->ac_tx_count[ac] = 0;
                                        target->tx_bndl_mask |= (1 << ac);
                                }
                        }
                } else {
                        /* tx bundling will reset the counter */
                        if (ac < WMM_NUM_AC)
                                target->ac_tx_count[ac] = 0;
                }
        }

        endpoint->tx_proc_cnt = 0;
        spin_unlock_bh(&target->tx_lock);
}

static bool ath6kl_htc_tx_try(struct htc_target *target,
                              struct htc_endpoint *endpoint,
                              struct htc_packet *tx_pkt)
{
        struct htc_ep_callbacks ep_cb;
        int txq_depth;
        bool overflow = false;

        ep_cb = endpoint->ep_cb;

        spin_lock_bh(&target->tx_lock);
        txq_depth = get_queue_depth(&endpoint->txq);
        spin_unlock_bh(&target->tx_lock);

        if (txq_depth >= endpoint->max_txq_depth)
                overflow = true;

        if (overflow)
                ath6kl_dbg(ATH6KL_DBG_HTC,
                           "htc tx overflow ep %d depth %d max %d\n",
                           endpoint->eid, txq_depth,
                           endpoint->max_txq_depth);

        if (overflow && ep_cb.tx_full) {
                if (ep_cb.tx_full(endpoint->target, tx_pkt) ==
                    HTC_SEND_FULL_DROP) {
                        endpoint->ep_st.tx_dropped += 1;
                        return false;
                }
        }

        spin_lock_bh(&target->tx_lock);
        list_add_tail(&tx_pkt->list, &endpoint->txq);
        spin_unlock_bh(&target->tx_lock);

        ath6kl_htc_tx_from_queue(target, endpoint);

        return true;
}

static void htc_chk_ep_txq(struct htc_target *target)
{
        struct htc_endpoint *endpoint;
        struct htc_endpoint_credit_dist *cred_dist;

        /*
         * Run through the credit distribution list to see if there are
         * packets queued. NOTE: no locks need to be taken since the
         * distribution list is not dynamic (cannot be re-ordered) and we
         * are not modifying any state.
         */
        list_for_each_entry(cred_dist, &target->cred_dist_list, list) {
                endpoint = cred_dist->htc_ep;

                spin_lock_bh(&target->tx_lock);
                if (!list_empty(&endpoint->txq)) {
                        ath6kl_dbg(ATH6KL_DBG_HTC,
                                   "htc creds ep %d credits %d pkts %d\n",
                                   cred_dist->endpoint,
                                   endpoint->cred_dist.credits,
                                   get_queue_depth(&endpoint->txq));
                        spin_unlock_bh(&target->tx_lock);
                        /*
                         * Try to start the stalled queue, this list is
                         * ordered by priority. If there are credits
                         * available the highest priority queue will get a
                         * chance to reclaim credits from lower priority
                         * ones.
                         */
                        ath6kl_htc_tx_from_queue(target, endpoint);
                        spin_lock_bh(&target->tx_lock);
                }
                spin_unlock_bh(&target->tx_lock);
        }
}

static int htc_setup_tx_complete(struct htc_target *target)
{
        struct htc_packet *send_pkt = NULL;
        int status;

        send_pkt = htc_get_control_buf(target, true);

        if (!send_pkt)
                return -ENOMEM;

        if (target->htc_tgt_ver >= HTC_VERSION_2P1) {
                struct htc_setup_comp_ext_msg *setup_comp_ext;
                u32 flags = 0;

                setup_comp_ext =
                    (struct htc_setup_comp_ext_msg *)send_pkt->buf;
                memset(setup_comp_ext, 0, sizeof(*setup_comp_ext));
                setup_comp_ext->msg_id =
                        cpu_to_le16(HTC_MSG_SETUP_COMPLETE_EX_ID);

                if (target->msg_per_bndl_max > 0) {
                        /* Indicate HTC bundling to the target */
                        flags |= HTC_SETUP_COMP_FLG_RX_BNDL_EN;
                        setup_comp_ext->msg_per_rxbndl =
                                                target->msg_per_bndl_max;
                }

                memcpy(&setup_comp_ext->flags, &flags,
                       sizeof(setup_comp_ext->flags));
                set_htc_pkt_info(send_pkt, NULL, (u8 *) setup_comp_ext,
                                 sizeof(struct htc_setup_comp_ext_msg),
                                 ENDPOINT_0, HTC_SERVICE_TX_PACKET_TAG);

        } else {
                struct htc_setup_comp_msg *setup_comp;
                setup_comp = (struct htc_setup_comp_msg *)send_pkt->buf;
                memset(setup_comp, 0, sizeof(struct htc_setup_comp_msg));
                setup_comp->msg_id = cpu_to_le16(HTC_MSG_SETUP_COMPLETE_ID);
                set_htc_pkt_info(send_pkt, NULL, (u8 *) setup_comp,
                                 sizeof(struct htc_setup_comp_msg),
                                 ENDPOINT_0, HTC_SERVICE_TX_PACKET_TAG);
        }

        /* we want synchronous operation */
        send_pkt->completion = NULL;
        ath6kl_htc_tx_prep_pkt(send_pkt, 0, 0, 0);
        status = ath6kl_htc_tx_issue(target, send_pkt);
        htc_reclaim_txctrl_buf(target, send_pkt);

        return status;
}

static void ath6kl_htc_set_credit_dist(struct htc_target *target,
                                struct ath6kl_htc_credit_info *credit_info,
                                u16 srvc_pri_order[], int list_len)
{
        struct htc_endpoint *endpoint;
        int i, ep;

        target->credit_info = credit_info;

        list_add_tail(&target->endpoint[ENDPOINT_0].cred_dist.list,
                      &target->cred_dist_list);

        for (i = 0; i < list_len; i++) {
                for (ep = ENDPOINT_1; ep < ENDPOINT_MAX; ep++) {
                        endpoint = &target->endpoint[ep];
                        if (endpoint->svc_id == srvc_pri_order[i]) {
                                list_add_tail(&endpoint->cred_dist.list,
                                              &target->cred_dist_list);
                                break;
                        }
                }
                if (ep >= ENDPOINT_MAX) {
                        WARN_ON(1);
                        return;
                }
        }
}

static int ath6kl_htc_mbox_tx(struct htc_target *target,
                              struct htc_packet *packet)
{
        struct htc_endpoint *endpoint;
        struct list_head queue;

        ath6kl_dbg(ATH6KL_DBG_HTC,
                   "htc tx ep id %d buf 0x%p len %d\n",
                   packet->endpoint, packet->buf, packet->act_len);

        if (packet->endpoint >= ENDPOINT_MAX) {
                WARN_ON(1);
                return -EINVAL;
        }

        endpoint = &target->endpoint[packet->endpoint];

        if (!ath6kl_htc_tx_try(target, endpoint, packet)) {
                packet->status = (target->htc_flags & HTC_OP_STATE_STOPPING) ?
                                 -ECANCELED : -ENOSPC;
                INIT_LIST_HEAD(&queue);
                list_add(&packet->list, &queue);
                htc_tx_complete(endpoint, &queue);
        }

        return 0;
}

/* flush endpoint TX queue */
static void ath6kl_htc_mbox_flush_txep(struct htc_target *target,
                           enum htc_endpoint_id eid, u16 tag)
{
        struct htc_packet *packet, *tmp_pkt;
        struct list_head discard_q, container;
        struct htc_endpoint *endpoint = &target->endpoint[eid];

        if (!endpoint->svc_id) {
                WARN_ON(1);
                return;
        }

        /* initialize the discard queue */
        INIT_LIST_HEAD(&discard_q);

        spin_lock_bh(&target->tx_lock);

        list_for_each_entry_safe(packet, tmp_pkt, &endpoint->txq, list) {
                if ((tag == HTC_TX_PACKET_TAG_ALL) ||
                    (tag == packet->info.tx.tag))
                        list_move_tail(&packet->list, &discard_q);
        }

        spin_unlock_bh(&target->tx_lock);

        list_for_each_entry_safe(packet, tmp_pkt, &discard_q, list) {
                packet->status = -ECANCELED;
                list_del(&packet->list);
                ath6kl_dbg(ATH6KL_DBG_HTC,
                           "htc tx flushing pkt 0x%p len %d  ep %d tag 0x%x\n",
                           packet, packet->act_len,
                           packet->endpoint, packet->info.tx.tag);

                INIT_LIST_HEAD(&container);
                list_add_tail(&packet->list, &container);
                htc_tx_complete(endpoint, &container);
        }
}

static void ath6kl_htc_flush_txep_all(struct htc_target *target)
{
        struct htc_endpoint *endpoint;
        int i;

        dump_cred_dist_stats(target);

        for (i = ENDPOINT_0; i < ENDPOINT_MAX; i++) {
                endpoint = &target->endpoint[i];
                if (endpoint->svc_id == 0)
                        /* not in use.. */
                        continue;
                ath6kl_htc_mbox_flush_txep(target, i, HTC_TX_PACKET_TAG_ALL);
        }
}

static void ath6kl_htc_mbox_activity_changed(struct htc_target *target,
                                             enum htc_endpoint_id eid,
                                             bool active)
{
        struct htc_endpoint *endpoint = &target->endpoint[eid];
        bool dist = false;

        if (endpoint->svc_id == 0) {
                WARN_ON(1);
                return;
        }

        spin_lock_bh(&target->tx_lock);

        if (active) {
                if (!(endpoint->cred_dist.dist_flags & HTC_EP_ACTIVE)) {
                        endpoint->cred_dist.dist_flags |= HTC_EP_ACTIVE;
                        dist = true;
                }
        } else {
                if (endpoint->cred_dist.dist_flags & HTC_EP_ACTIVE) {
                        endpoint->cred_dist.dist_flags &= ~HTC_EP_ACTIVE;
                        dist = true;
                }
        }

        if (dist) {
                endpoint->cred_dist.txq_depth =
                        get_queue_depth(&endpoint->txq);

                ath6kl_dbg(ATH6KL_DBG_HTC,
                           "htc tx activity ctxt 0x%p dist 0x%p\n",
                           target->credit_info, &target->cred_dist_list);

                ath6kl_credit_distribute(target->credit_info,
                                         &target->cred_dist_list,
                                         HTC_CREDIT_DIST_ACTIVITY_CHANGE);
        }

        spin_unlock_bh(&target->tx_lock);

        if (dist && !active)
                htc_chk_ep_txq(target);
}

/* HTC Rx */

static inline void ath6kl_htc_rx_update_stats(struct htc_endpoint *endpoint,
                                              int n_look_ahds)
{
        endpoint->ep_st.rx_pkts++;
        if (n_look_ahds == 1)
                endpoint->ep_st.rx_lkahds++;
        else if (n_look_ahds > 1)
                endpoint->ep_st.rx_bundle_lkahd++;
}

static inline bool htc_valid_rx_frame_len(struct htc_target *target,
                                          enum htc_endpoint_id eid, int len)
{
        return (eid == target->dev->ar->ctrl_ep) ?
                len <= ATH6KL_BUFFER_SIZE : len <= ATH6KL_AMSDU_BUFFER_SIZE;
}

static int htc_add_rxbuf(struct htc_target *target, struct htc_packet *packet)
{
        struct list_head queue;

        INIT_LIST_HEAD(&queue);
        list_add_tail(&packet->list, &queue);
        return ath6kl_htc_mbox_add_rxbuf_multiple(target, &queue);
}

static void htc_reclaim_rxbuf(struct htc_target *target,
                              struct htc_packet *packet,
                              struct htc_endpoint *ep)
{
        if (packet->info.rx.rx_flags & HTC_RX_PKT_NO_RECYCLE) {
                htc_rxpkt_reset(packet);
                packet->status = -ECANCELED;
                ep->ep_cb.rx(ep->target, packet);
        } else {
                htc_rxpkt_reset(packet);
                htc_add_rxbuf((void *)(target), packet);
        }
}

static void reclaim_rx_ctrl_buf(struct htc_target *target,
                                struct htc_packet *packet)
{
        spin_lock_bh(&target->htc_lock);
        list_add_tail(&packet->list, &target->free_ctrl_rxbuf);
        spin_unlock_bh(&target->htc_lock);
}

static int ath6kl_htc_rx_packet(struct htc_target *target,
                                struct htc_packet *packet,
                                u32 rx_len)
{
        struct ath6kl_device *dev = target->dev;
        u32 padded_len;
        int status;

        padded_len = CALC_TXRX_PADDED_LEN(target, rx_len);

        if (padded_len > packet->buf_len) {
                ath6kl_err("not enough receive space for packet - padlen %d recvlen %d bufferlen %d\n",
                           padded_len, rx_len, packet->buf_len);
                return -ENOMEM;
        }

        ath6kl_dbg(ATH6KL_DBG_HTC,
                   "htc rx 0x%p hdr 0x%x len %d mbox 0x%x\n",
                   packet, packet->info.rx.exp_hdr,
                   padded_len, dev->ar->mbox_info.htc_addr);

        status = hif_read_write_sync(dev->ar,
                                     dev->ar->mbox_info.htc_addr,
                                     packet->buf, padded_len,
                                     HIF_RD_SYNC_BLOCK_FIX);

        packet->status = status;

        return status;
}

/*
 * optimization for recv packets, we can indicate a
 * "hint" that there are more  single-packets to fetch
 * on this endpoint.
 */
static void ath6kl_htc_rx_set_indicate(u32 lk_ahd,
                                       struct htc_endpoint *endpoint,
                                       struct htc_packet *packet)
{
        struct htc_frame_hdr *htc_hdr = (struct htc_frame_hdr *)&lk_ahd;

        if (htc_hdr->eid == packet->endpoint) {
                if (!list_empty(&endpoint->rx_bufq))
                        packet->info.rx.indicat_flags |=
                                        HTC_RX_FLAGS_INDICATE_MORE_PKTS;
        }
}

static void ath6kl_htc_rx_chk_water_mark(struct htc_endpoint *endpoint)
{
        struct htc_ep_callbacks ep_cb = endpoint->ep_cb;

        if (ep_cb.rx_refill_thresh > 0) {
                spin_lock_bh(&endpoint->target->rx_lock);
                if (get_queue_depth(&endpoint->rx_bufq)
                    < ep_cb.rx_refill_thresh) {
                        spin_unlock_bh(&endpoint->target->rx_lock);
                        ep_cb.rx_refill(endpoint->target, endpoint->eid);
                        return;
                }
                spin_unlock_bh(&endpoint->target->rx_lock);
        }
}

/* This function is called with rx_lock held */
static int ath6kl_htc_rx_setup(struct htc_target *target,
                               struct htc_endpoint *ep,
                               u32 *lk_ahds, struct list_head *queue, int n_msg)
{
        struct htc_packet *packet;
        /* FIXME: type of lk_ahds can't be right */
        struct htc_frame_hdr *htc_hdr = (struct htc_frame_hdr *)lk_ahds;
        struct htc_ep_callbacks ep_cb;
        int status = 0, j, full_len;
        bool no_recycle;

        full_len = CALC_TXRX_PADDED_LEN(target,
                                        le16_to_cpu(htc_hdr->payld_len) +
                                        sizeof(*htc_hdr));

        if (!htc_valid_rx_frame_len(target, ep->eid, full_len)) {
                ath6kl_warn("Rx buffer requested with invalid length htc_hdr:eid %d, flags 0x%x, len %d\n",
                            htc_hdr->eid, htc_hdr->flags,
                            le16_to_cpu(htc_hdr->payld_len));
                return -EINVAL;
        }

        ep_cb = ep->ep_cb;
        for (j = 0; j < n_msg; j++) {
                /*
                 * Reset flag, any packets allocated using the
                 * rx_alloc() API cannot be recycled on
                 * cleanup,they must be explicitly returned.
                 */
                no_recycle = false;

                if (ep_cb.rx_allocthresh &&
                    (full_len > ep_cb.rx_alloc_thresh)) {
                        ep->ep_st.rx_alloc_thresh_hit += 1;
                        ep->ep_st.rxalloc_thresh_byte +=
                                le16_to_cpu(htc_hdr->payld_len);

                        spin_unlock_bh(&target->rx_lock);
                        no_recycle = true;

                        packet = ep_cb.rx_allocthresh(ep->target, ep->eid,
                                                      full_len);
                        spin_lock_bh(&target->rx_lock);
                } else {
                        /* refill handler is being used */
                        if (list_empty(&ep->rx_bufq)) {
                                if (ep_cb.rx_refill) {
                                        spin_unlock_bh(&target->rx_lock);
                                        ep_cb.rx_refill(ep->target, ep->eid);
                                        spin_lock_bh(&target->rx_lock);
                                }
                        }

                        if (list_empty(&ep->rx_bufq)) {
                                packet = NULL;
                        } else {
                                packet = list_first_entry(&ep->rx_bufq,
                                                struct htc_packet, list);
                                list_del(&packet->list);
                        }
                }

                if (!packet) {
                        target->rx_st_flags |= HTC_RECV_WAIT_BUFFERS;
                        target->ep_waiting = ep->eid;
                        return -ENOSPC;
                }

                /* clear flags */
                packet->info.rx.rx_flags = 0;
                packet->info.rx.indicat_flags = 0;
                packet->status = 0;

                if (no_recycle)
                        /*
                         * flag that these packets cannot be
                         * recycled, they have to be returned to
                         * the user
                         */
                        packet->info.rx.rx_flags |= HTC_RX_PKT_NO_RECYCLE;

                /* Caller needs to free this upon any failure */
                list_add_tail(&packet->list, queue);

                if (target->htc_flags & HTC_OP_STATE_STOPPING) {
                        status = -ECANCELED;
                        break;
                }

                if (j) {
                        packet->info.rx.rx_flags |= HTC_RX_PKT_REFRESH_HDR;
                        packet->info.rx.exp_hdr = 0xFFFFFFFF;
                } else
                        /* set expected look ahead */
                        packet->info.rx.exp_hdr = *lk_ahds;

                packet->act_len = le16_to_cpu(htc_hdr->payld_len) +
                        HTC_HDR_LENGTH;
        }

        return status;
}

static int ath6kl_htc_rx_alloc(struct htc_target *target,
                               u32 lk_ahds[], int msg,
                               struct htc_endpoint *endpoint,
                               struct list_head *queue)
{
        int status = 0;
        struct htc_packet *packet, *tmp_pkt;
        struct htc_frame_hdr *htc_hdr;
        int i, n_msg;

        spin_lock_bh(&target->rx_lock);

        for (i = 0; i < msg; i++) {
                htc_hdr = (struct htc_frame_hdr *)&lk_ahds[i];

                if (htc_hdr->eid >= ENDPOINT_MAX) {
                        ath6kl_err("invalid ep in look-ahead: %d\n",
                                   htc_hdr->eid);
                        status = -ENOMEM;
                        break;
                }

                if (htc_hdr->eid != endpoint->eid) {
                        ath6kl_err("invalid ep in look-ahead: %d should be : %d (index:%d)\n",
                                   htc_hdr->eid, endpoint->eid, i);
                        status = -ENOMEM;
                        break;
                }

                if (le16_to_cpu(htc_hdr->payld_len) > HTC_MAX_PAYLOAD_LENGTH) {
                        ath6kl_err("payload len %d exceeds max htc : %d !\n",
                                   htc_hdr->payld_len,
                                   (u32) HTC_MAX_PAYLOAD_LENGTH);
                        status = -ENOMEM;
                        break;
                }

                if (endpoint->svc_id == 0) {
                        ath6kl_err("ep %d is not connected !\n", htc_hdr->eid);
                        status = -ENOMEM;
                        break;
                }

                if (htc_hdr->flags & HTC_FLG_RX_BNDL_CNT) {
                        /*
                         * HTC header indicates that every packet to follow
                         * has the same padded length so that it can be
                         * optimally fetched as a full bundle.
                         */
                        n_msg = (htc_hdr->flags & HTC_FLG_RX_BNDL_CNT) >>
                                HTC_FLG_RX_BNDL_CNT_S;

                        /* the count doesn't include the starter frame */
                        n_msg++;
                        if (n_msg > target->msg_per_bndl_max) {
                                status = -ENOMEM;
                                break;
                        }

                        endpoint->ep_st.rx_bundle_from_hdr += 1;
                        ath6kl_dbg(ATH6KL_DBG_HTC,
                                   "htc rx bundle pkts %d\n",
                                   n_msg);
                } else
                        /* HTC header only indicates 1 message to fetch */
                        n_msg = 1;

                /* Setup packet buffers for each message */
                status = ath6kl_htc_rx_setup(target, endpoint, &lk_ahds[i],
                                             queue, n_msg);

                /*
                 * This is due to unavailability of buffers to rx entire data.
                 * Return no error so that free buffers from queue can be used
                 * to receive partial data.
                 */
                if (status == -ENOSPC) {
                        spin_unlock_bh(&target->rx_lock);
                        return 0;
                }

                if (status)
                        break;
        }

        spin_unlock_bh(&target->rx_lock);

        if (status) {
                list_for_each_entry_safe(packet, tmp_pkt, queue, list) {
                        list_del(&packet->list);
                        htc_reclaim_rxbuf(target, packet,
                                          &target->endpoint[packet->endpoint]);
                }
        }

        return status;
}

static void htc_ctrl_rx(struct htc_target *context, struct htc_packet *packets)
{
        if (packets->endpoint != ENDPOINT_0) {
                WARN_ON(1);
                return;
        }

        if (packets->status == -ECANCELED) {
                reclaim_rx_ctrl_buf(context, packets);
                return;
        }

        if (packets->act_len > 0) {
                ath6kl_err("htc_ctrl_rx, got message with len:%zu\n",
                           packets->act_len + HTC_HDR_LENGTH);

                ath6kl_dbg_dump(ATH6KL_DBG_HTC,
                                "htc rx unexpected endpoint 0 message", "",
                                packets->buf - HTC_HDR_LENGTH,
                                packets->act_len + HTC_HDR_LENGTH);
        }

        htc_reclaim_rxbuf(context, packets, &context->endpoint[0]);
}

static void htc_proc_cred_rpt(struct htc_target *target,
                              struct htc_credit_report *rpt,
                              int n_entries,
                              enum htc_endpoint_id from_ep)
{
        struct htc_endpoint *endpoint;
        int tot_credits = 0, i;
        bool dist = false;

        spin_lock_bh(&target->tx_lock);

        for (i = 0; i < n_entries; i++, rpt++) {
                if (rpt->eid >= ENDPOINT_MAX) {
                        WARN_ON(1);
                        spin_unlock_bh(&target->tx_lock);
                        return;
                }

                endpoint = &target->endpoint[rpt->eid];

                ath6kl_dbg(ATH6KL_DBG_CREDIT,
                           "credit report ep %d credits %d\n",
                           rpt->eid, rpt->credits);

                endpoint->ep_st.tx_cred_rpt += 1;
                endpoint->ep_st.cred_retnd += rpt->credits;

                if (from_ep == rpt->eid) {
                        /*
                         * This credit report arrived on the same endpoint
                         * indicating it arrived in an RX packet.
                         */
                        endpoint->ep_st.cred_from_rx += rpt->credits;
                        endpoint->ep_st.cred_rpt_from_rx += 1;
                } else if (from_ep == ENDPOINT_0) {
                        /* credit arrived on endpoint 0 as a NULL message */
                        endpoint->ep_st.cred_from_ep0 += rpt->credits;
                        endpoint->ep_st.cred_rpt_ep0 += 1;
                } else {
                        endpoint->ep_st.cred_from_other += rpt->credits;
                        endpoint->ep_st.cred_rpt_from_other += 1;
                }

                if (rpt->eid == ENDPOINT_0)
                        /* always give endpoint 0 credits back */
                        endpoint->cred_dist.credits += rpt->credits;
                else {
                        endpoint->cred_dist.cred_to_dist += rpt->credits;
                        dist = true;
                }

                /*
                 * Refresh tx depth for distribution function that will
                 * recover these credits NOTE: this is only valid when
                 * there are credits to recover!
                 */
                endpoint->cred_dist.txq_depth =
                        get_queue_depth(&endpoint->txq);

                tot_credits += rpt->credits;
        }

        if (dist) {
                /*
                 * This was a credit return based on a completed send
                 * operations note, this is done with the lock held
                 */
                ath6kl_credit_distribute(target->credit_info,
                                         &target->cred_dist_list,
                                         HTC_CREDIT_DIST_SEND_COMPLETE);
        }

        spin_unlock_bh(&target->tx_lock);

        if (tot_credits)
                htc_chk_ep_txq(target);
}

static int htc_parse_trailer(struct htc_target *target,
                             struct htc_record_hdr *record,
                             u8 *record_buf, u32 *next_lk_ahds,
                             enum htc_endpoint_id endpoint,
                             int *n_lk_ahds)
{
        struct htc_bundle_lkahd_rpt *bundle_lkahd_rpt;
        struct htc_lookahead_report *lk_ahd;
        int len;

        switch (record->rec_id) {
        case HTC_RECORD_CREDITS:
                len = record->len / sizeof(struct htc_credit_report);
                if (!len) {
                        WARN_ON(1);
                        return -EINVAL;
                }

                htc_proc_cred_rpt(target,
                                  (struct htc_credit_report *) record_buf,
                                  len, endpoint);
                break;
        case HTC_RECORD_LOOKAHEAD:
                len = record->len / sizeof(*lk_ahd);
                if (!len) {
                        WARN_ON(1);
                        return -EINVAL;
                }

                lk_ahd = (struct htc_lookahead_report *) record_buf;
                if ((lk_ahd->pre_valid == ((~lk_ahd->post_valid) & 0xFF)) &&
                    next_lk_ahds) {
                        ath6kl_dbg(ATH6KL_DBG_HTC,
                                   "htc rx lk_ahd found pre_valid 0x%x post_valid 0x%x\n",
                                   lk_ahd->pre_valid, lk_ahd->post_valid);

                        /* look ahead bytes are valid, copy them over */
                        memcpy((u8 *)&next_lk_ahds[0], lk_ahd->lk_ahd, 4);

                        ath6kl_dbg_dump(ATH6KL_DBG_HTC,
                                        "htc rx next look ahead",
                                        "", next_lk_ahds, 4);

                        *n_lk_ahds = 1;
                }
                break;
        case HTC_RECORD_LOOKAHEAD_BUNDLE:
                len = record->len / sizeof(*bundle_lkahd_rpt);
                if (!len || (len > HTC_HOST_MAX_MSG_PER_BUNDLE)) {
                        WARN_ON(1);
                        return -EINVAL;
                }

                if (next_lk_ahds) {
                        int i;

                        bundle_lkahd_rpt =
                                (struct htc_bundle_lkahd_rpt *) record_buf;

                        ath6kl_dbg_dump(ATH6KL_DBG_HTC, "htc rx bundle lk_ahd",
                                        "", record_buf, record->len);

                        for (i = 0; i < len; i++) {
                                memcpy((u8 *)&next_lk_ahds[i],
                                       bundle_lkahd_rpt->lk_ahd, 4);
                                bundle_lkahd_rpt++;
                        }

                        *n_lk_ahds = i;
                }
                break;
        default:
                ath6kl_err("unhandled record: id:%d len:%d\n",
                           record->rec_id, record->len);
                break;
        }

        return 0;
}

static int htc_proc_trailer(struct htc_target *target,
                            u8 *buf, int len, u32 *next_lk_ahds,
                            int *n_lk_ahds, enum htc_endpoint_id endpoint)
{
        struct htc_record_hdr *record;
        int orig_len;
        int status;
        u8 *record_buf;
        u8 *orig_buf;

        ath6kl_dbg(ATH6KL_DBG_HTC, "htc rx trailer len %d\n", len);
        ath6kl_dbg_dump(ATH6KL_DBG_HTC, NULL, "", buf, len);

        orig_buf = buf;
        orig_len = len;
        status = 0;

        while (len > 0) {
                if (len < sizeof(struct htc_record_hdr)) {
                        status = -ENOMEM;
                        break;
                }
                /* these are byte aligned structs */
                record = (struct htc_record_hdr *) buf;
                len -= sizeof(struct htc_record_hdr);
                buf += sizeof(struct htc_record_hdr);

                if (record->len > len) {
                        ath6kl_err("invalid record len: %d (id:%d) buf has: %d bytes left\n",
                                   record->len, record->rec_id, len);
                        status = -ENOMEM;
                        break;
                }
                record_buf = buf;

                status = htc_parse_trailer(target, record, record_buf,
                                           next_lk_ahds, endpoint, n_lk_ahds);

                if (status)
                        break;

                /* advance buffer past this record for next time around */
                buf += record->len;
                len -= record->len;
        }

        if (status)
                ath6kl_dbg_dump(ATH6KL_DBG_HTC, "htc rx bad trailer",
                                "", orig_buf, orig_len);

        return status;
}

static int ath6kl_htc_rx_process_hdr(struct htc_target *target,
                                     struct htc_packet *packet,
                                     u32 *next_lkahds, int *n_lkahds)
{
        int status = 0;
        u16 payload_len;
        u32 lk_ahd;
        struct htc_frame_hdr *htc_hdr = (struct htc_frame_hdr *)packet->buf;

        if (n_lkahds != NULL)
                *n_lkahds = 0;

        /*
         * NOTE: we cannot assume the alignment of buf, so we use the safe
         * macros to retrieve 16 bit fields.
         */
        payload_len = le16_to_cpu(get_unaligned(&htc_hdr->payld_len));

        memcpy((u8 *)&lk_ahd, packet->buf, sizeof(lk_ahd));

        if (packet->info.rx.rx_flags & HTC_RX_PKT_REFRESH_HDR) {
                /*
                 * Refresh the expected header and the actual length as it
                 * was unknown when this packet was grabbed as part of the
                 * bundle.
                 */
                packet->info.rx.exp_hdr = lk_ahd;
                packet->act_len = payload_len + HTC_HDR_LENGTH;

                /* validate the actual header that was refreshed  */
                if (packet->act_len > packet->buf_len) {
                        ath6kl_err("refreshed hdr payload len (%d) in bundled recv is invalid (hdr: 0x%X)\n",
                                   payload_len, lk_ahd);
                        /*
                         * Limit this to max buffer just to print out some
                         * of the buffer.
                         */
                        packet->act_len = min(packet->act_len, packet->buf_len);
                        status = -ENOMEM;
                        goto fail_rx;
                }

                if (packet->endpoint != htc_hdr->eid) {
                        ath6kl_err("refreshed hdr ep (%d) does not match expected ep (%d)\n",
                                   htc_hdr->eid, packet->endpoint);
                        status = -ENOMEM;
                        goto fail_rx;
                }
        }

        if (lk_ahd != packet->info.rx.exp_hdr) {
                ath6kl_err("%s(): lk_ahd mismatch! (pPkt:0x%p flags:0x%X)\n",
                           __func__, packet, packet->info.rx.rx_flags);
                ath6kl_dbg_dump(ATH6KL_DBG_HTC, "htc rx expected lk_ahd",
                                "", &packet->info.rx.exp_hdr, 4);
                ath6kl_dbg_dump(ATH6KL_DBG_HTC, "htc rx current header",
                                "", (u8 *)&lk_ahd, sizeof(lk_ahd));
                status = -ENOMEM;
                goto fail_rx;
        }

        if (htc_hdr->flags & HTC_FLG_RX_TRAILER) {
                if (htc_hdr->ctrl[0] < sizeof(struct htc_record_hdr) ||
                    htc_hdr->ctrl[0] > payload_len) {
                        ath6kl_err("%s(): invalid hdr (payload len should be :%d, CB[0] is:%d)\n",
                                   __func__, payload_len, htc_hdr->ctrl[0]);
                        status = -ENOMEM;
                        goto fail_rx;
                }

                if (packet->info.rx.rx_flags & HTC_RX_PKT_IGNORE_LOOKAHEAD) {
                        next_lkahds = NULL;
                        n_lkahds = NULL;
                }

                status = htc_proc_trailer(target, packet->buf + HTC_HDR_LENGTH
                                          + payload_len - htc_hdr->ctrl[0],
                                          htc_hdr->ctrl[0], next_lkahds,
                                           n_lkahds, packet->endpoint);

                if (status)
                        goto fail_rx;

                packet->act_len -= htc_hdr->ctrl[0];
        }

        packet->buf += HTC_HDR_LENGTH;
        packet->act_len -= HTC_HDR_LENGTH;

fail_rx:
        if (status)
                ath6kl_dbg_dump(ATH6KL_DBG_HTC, "htc rx bad packet",
                                "", packet->buf, packet->act_len);

        return status;
}

static void ath6kl_htc_rx_complete(struct htc_endpoint *endpoint,
                                   struct htc_packet *packet)
{
                ath6kl_dbg(ATH6KL_DBG_HTC,
                           "htc rx complete ep %d packet 0x%p\n",
                           endpoint->eid, packet);

                endpoint->ep_cb.rx(endpoint->target, packet);
}

static int ath6kl_htc_rx_bundle(struct htc_target *target,
                                struct list_head *rxq,
                                struct list_head *sync_compq,
                                int *n_pkt_fetched, bool part_bundle)
{
        struct hif_scatter_req *scat_req;
        struct htc_packet *packet;
        int rem_space = target->max_rx_bndl_sz;
        int n_scat_pkt, status = 0, i, len;

        n_scat_pkt = get_queue_depth(rxq);
        n_scat_pkt = min(n_scat_pkt, target->msg_per_bndl_max);

        if ((get_queue_depth(rxq) - n_scat_pkt) > 0) {
                /*
                 * We were forced to split this bundle receive operation
                 * all packets in this partial bundle must have their
                 * lookaheads ignored.
                 */
                part_bundle = true;

                /*
                 * This would only happen if the target ignored our max
                 * bundle limit.
                 */
                ath6kl_warn("%s(): partial bundle detected num:%d , %d\n",
                            __func__, get_queue_depth(rxq), n_scat_pkt);
        }

        len = 0;

        ath6kl_dbg(ATH6KL_DBG_HTC,
                   "htc rx bundle depth %d pkts %d\n",
                   get_queue_depth(rxq), n_scat_pkt);

        scat_req = hif_scatter_req_get(target->dev->ar);

        if (scat_req == NULL)
                goto fail_rx_pkt;

        for (i = 0; i < n_scat_pkt; i++) {
                int pad_len;

                packet = list_first_entry(rxq, struct htc_packet, list);
                list_del(&packet->list);

                pad_len = CALC_TXRX_PADDED_LEN(target,
                                                   packet->act_len);

                if ((rem_space - pad_len) < 0) {
                        list_add(&packet->list, rxq);
                        break;
                }

                rem_space -= pad_len;

                if (part_bundle || (i < (n_scat_pkt - 1)))
                        /*
                         * Packet 0..n-1 cannot be checked for look-aheads
                         * since we are fetching a bundle the last packet
                         * however can have it's lookahead used
                         */
                        packet->info.rx.rx_flags |=
                            HTC_RX_PKT_IGNORE_LOOKAHEAD;

                /* NOTE: 1 HTC packet per scatter entry */
                scat_req->scat_list[i].buf = packet->buf;
                scat_req->scat_list[i].len = pad_len;

                packet->info.rx.rx_flags |= HTC_RX_PKT_PART_OF_BUNDLE;

                list_add_tail(&packet->list, sync_compq);

                WARN_ON(!scat_req->scat_list[i].len);
                len += scat_req->scat_list[i].len;
        }

        scat_req->len = len;
        scat_req->scat_entries = i;

        status = ath6kl_hif_submit_scat_req(target->dev, scat_req, true);

        if (!status)
                *n_pkt_fetched = i;

        /* free scatter request */
        hif_scatter_req_add(target->dev->ar, scat_req);

fail_rx_pkt:

        return status;
}

static int ath6kl_htc_rx_process_packets(struct htc_target *target,
                                         struct list_head *comp_pktq,
                                         u32 lk_ahds[],
                                         int *n_lk_ahd)
{
        struct htc_packet *packet, *tmp_pkt;
        struct htc_endpoint *ep;
        int status = 0;

        list_for_each_entry_safe(packet, tmp_pkt, comp_pktq, list) {
                ep = &target->endpoint[packet->endpoint];

                trace_ath6kl_htc_rx(packet->status, packet->endpoint,
                                    packet->buf, packet->act_len);

                /* process header for each of the recv packet */
                status = ath6kl_htc_rx_process_hdr(target, packet, lk_ahds,
                                                   n_lk_ahd);
                if (status)
                        return status;

                list_del(&packet->list);

                if (list_empty(comp_pktq)) {
                        /*
                         * Last packet's more packet flag is set
                         * based on the lookahead.
                         */
                        if (*n_lk_ahd > 0)
                                ath6kl_htc_rx_set_indicate(lk_ahds[0],
                                                           ep, packet);
                } else
                        /*
                         * Packets in a bundle automatically have
                         * this flag set.
                         */
                        packet->info.rx.indicat_flags |=
                                HTC_RX_FLAGS_INDICATE_MORE_PKTS;

                ath6kl_htc_rx_update_stats(ep, *n_lk_ahd);

                if (packet->info.rx.rx_flags & HTC_RX_PKT_PART_OF_BUNDLE)
                        ep->ep_st.rx_bundl += 1;

                ath6kl_htc_rx_complete(ep, packet);
        }

        return status;
}

static int ath6kl_htc_rx_fetch(struct htc_target *target,
                               struct list_head *rx_pktq,
                               struct list_head *comp_pktq)
{
        int fetched_pkts;
        bool part_bundle = false;
        int status = 0;
        struct list_head tmp_rxq;
        struct htc_packet *packet, *tmp_pkt;

        /* now go fetch the list of HTC packets */
        while (!list_empty(rx_pktq)) {
                fetched_pkts = 0;

                INIT_LIST_HEAD(&tmp_rxq);

                if (target->rx_bndl_enable && (get_queue_depth(rx_pktq) > 1)) {
                        /*
                         * There are enough packets to attempt a
                         * bundle transfer and recv bundling is
                         * allowed.
                         */
                        status = ath6kl_htc_rx_bundle(target, rx_pktq,
                                                      &tmp_rxq,
                                                      &fetched_pkts,
                                                      part_bundle);
                        if (status)
                                goto fail_rx;

                        if (!list_empty(rx_pktq))
                                part_bundle = true;

                        list_splice_tail_init(&tmp_rxq, comp_pktq);
                }

                if (!fetched_pkts) {
                        packet = list_first_entry(rx_pktq, struct htc_packet,
                                                   list);

                        /* fully synchronous */
                        packet->completion = NULL;

                        if (!list_is_singular(rx_pktq))
                                /*
                                 * look_aheads in all packet
                                 * except the last one in the
                                 * bundle must be ignored
                                 */
                                packet->info.rx.rx_flags |=
                                        HTC_RX_PKT_IGNORE_LOOKAHEAD;

                        /* go fetch the packet */
                        status = ath6kl_htc_rx_packet(target, packet,
                                                      packet->act_len);

                        list_move_tail(&packet->list, &tmp_rxq);

                        if (status)
                                goto fail_rx;

                        list_splice_tail_init(&tmp_rxq, comp_pktq);
                }
        }

        return 0;

fail_rx:

        /*
         * Cleanup any packets we allocated but didn't use to
         * actually fetch any packets.
         */

        list_for_each_entry_safe(packet, tmp_pkt, rx_pktq, list) {
                list_del(&packet->list);
                htc_reclaim_rxbuf(target, packet,
                                  &target->endpoint[packet->endpoint]);
        }

        list_for_each_entry_safe(packet, tmp_pkt, &tmp_rxq, list) {
                list_del(&packet->list);
                htc_reclaim_rxbuf(target, packet,
                                  &target->endpoint[packet->endpoint]);
        }

        return status;
}

int ath6kl_htc_rxmsg_pending_handler(struct htc_target *target,
                                     u32 msg_look_ahead, int *num_pkts)
{
        struct htc_packet *packets, *tmp_pkt;
        struct htc_endpoint *endpoint;
        struct list_head rx_pktq, comp_pktq;
        int status = 0;
        u32 look_aheads[HTC_HOST_MAX_MSG_PER_BUNDLE];
        int num_look_ahead = 1;
        enum htc_endpoint_id id;
        int n_fetched = 0;

        INIT_LIST_HEAD(&comp_pktq);
        *num_pkts = 0;

        /*
         * On first entry copy the look_aheads into our temp array for
         * processing
         */
        look_aheads[0] = msg_look_ahead;

        while (true) {
                /*
                 * First lookahead sets the expected endpoint IDs for all
                 * packets in a bundle.
                 */
                id = ((struct htc_frame_hdr *)&look_aheads[0])->eid;
                endpoint = &target->endpoint[id];

                if (id >= ENDPOINT_MAX) {
                        ath6kl_err("MsgPend, invalid endpoint in look-ahead: %d\n",
                                   id);
                        status = -ENOMEM;
                        break;
                }

                INIT_LIST_HEAD(&rx_pktq);
                INIT_LIST_HEAD(&comp_pktq);

                /*
                 * Try to allocate as many HTC RX packets indicated by the
                 * look_aheads.
                 */
                status = ath6kl_htc_rx_alloc(target, look_aheads,
                                             num_look_ahead, endpoint,
                                             &rx_pktq);
                if (status)
                        break;

                if (get_queue_depth(&rx_pktq) >= 2)
                        /*
                         * A recv bundle was detected, force IRQ status
                         * re-check again
                         */
                        target->chk_irq_status_cnt = 1;

                n_fetched += get_queue_depth(&rx_pktq);

                num_look_ahead = 0;

                status = ath6kl_htc_rx_fetch(target, &rx_pktq, &comp_pktq);

                if (!status)
                        ath6kl_htc_rx_chk_water_mark(endpoint);

                /* Process fetched packets */
                status = ath6kl_htc_rx_process_packets(target, &comp_pktq,
                                                       look_aheads,
                                                       &num_look_ahead);

                if (!num_look_ahead || status)
                        break;

                /*
                 * For SYNCH processing, if we get here, we are running
                 * through the loop again due to a detected lookahead. Set
                 * flag that we should re-check IRQ status registers again
                 * before leaving IRQ processing, this can net better
                 * performance in high throughput situations.
                 */
                target->chk_irq_status_cnt = 1;
        }

        if (status) {
                if (status != -ECANCELED)
                        ath6kl_err("failed to get pending recv messages: %d\n",
                                   status);

                /* cleanup any packets in sync completion queue */
                list_for_each_entry_safe(packets, tmp_pkt, &comp_pktq, list) {
                        list_del(&packets->list);
                        htc_reclaim_rxbuf(target, packets,
                                          &target->endpoint[packets->endpoint]);
                }

                if (target->htc_flags & HTC_OP_STATE_STOPPING) {
                        ath6kl_warn("host is going to stop blocking receiver for htc_stop\n");
                        ath6kl_hif_rx_control(target->dev, false);
                }
        }

        /*
         * Before leaving, check to see if host ran out of buffers and
         * needs to stop the receiver.
         */
        if (target->rx_st_flags & HTC_RECV_WAIT_BUFFERS) {
                ath6kl_warn("host has no rx buffers blocking receiver to prevent overrun\n");
                ath6kl_hif_rx_control(target->dev, false);
        }
        *num_pkts = n_fetched;

        return status;
}

/*
 * Synchronously wait for a control message from the target,
 * This function is used at initialization time ONLY.  At init messages
 * on ENDPOINT 0 are expected.
 */
static struct htc_packet *htc_wait_for_ctrl_msg(struct htc_target *target)
{
        struct htc_packet *packet = NULL;
        struct htc_frame_look_ahead look_ahead;

        if (ath6kl_hif_poll_mboxmsg_rx(target->dev, &look_ahead.word,
                                       HTC_TARGET_RESPONSE_TIMEOUT))
                return NULL;

        ath6kl_dbg(ATH6KL_DBG_HTC,
                   "htc rx wait ctrl look_ahead 0x%X\n", look_ahead.word);

        if (look_ahead.eid != ENDPOINT_0)
                return NULL;

        packet = htc_get_control_buf(target, false);

        if (!packet)
                return NULL;

        packet->info.rx.rx_flags = 0;
        packet->info.rx.exp_hdr = look_ahead.word;
        packet->act_len = le16_to_cpu(look_ahead.payld_len) + HTC_HDR_LENGTH;

        if (packet->act_len > packet->buf_len)
                goto fail_ctrl_rx;

        /* we want synchronous operation */
        packet->completion = NULL;

        /* get the message from the device, this will block */
        if (ath6kl_htc_rx_packet(target, packet, packet->act_len))
                goto fail_ctrl_rx;

        trace_ath6kl_htc_rx(packet->status, packet->endpoint,
                            packet->buf, packet->act_len);

        /* process receive header */
        packet->status = ath6kl_htc_rx_process_hdr(target, packet, NULL, NULL);

        if (packet->status) {
                ath6kl_err("htc_wait_for_ctrl_msg, ath6kl_htc_rx_process_hdr failed (status = %d)\n",
                           packet->status);
                goto fail_ctrl_rx;
        }

        return packet;

fail_ctrl_rx:
        if (packet != NULL) {
                htc_rxpkt_reset(packet);
                reclaim_rx_ctrl_buf(target, packet);
        }

        return NULL;
}

static int ath6kl_htc_mbox_add_rxbuf_multiple(struct htc_target *target,
                                  struct list_head *pkt_queue)
{
        struct htc_endpoint *endpoint;
        struct htc_packet *first_pkt;
        bool rx_unblock = false;
        int status = 0, depth;

        if (list_empty(pkt_queue))
                return -ENOMEM;

        first_pkt = list_first_entry(pkt_queue, struct htc_packet, list);

        if (first_pkt->endpoint >= ENDPOINT_MAX)
                return status;

        depth = get_queue_depth(pkt_queue);

        ath6kl_dbg(ATH6KL_DBG_HTC,
                   "htc rx add multiple ep id %d cnt %d len %d\n",
                first_pkt->endpoint, depth, first_pkt->buf_len);

        endpoint = &target->endpoint[first_pkt->endpoint];

        if (target->htc_flags & HTC_OP_STATE_STOPPING) {
                struct htc_packet *packet, *tmp_pkt;

                /* walk through queue and mark each one canceled */
                list_for_each_entry_safe(packet, tmp_pkt, pkt_queue, list) {
                        packet->status = -ECANCELED;
                        list_del(&packet->list);
                        ath6kl_htc_rx_complete(endpoint, packet);
                }

                return status;
        }

        spin_lock_bh(&target->rx_lock);

        list_splice_tail_init(pkt_queue, &endpoint->rx_bufq);

        /* check if we are blocked waiting for a new buffer */
        if (target->rx_st_flags & HTC_RECV_WAIT_BUFFERS) {
                if (target->ep_waiting == first_pkt->endpoint) {
                        ath6kl_dbg(ATH6KL_DBG_HTC,
                                   "htc rx blocked on ep %d, unblocking\n",
                                   target->ep_waiting);
                        target->rx_st_flags &= ~HTC_RECV_WAIT_BUFFERS;
                        target->ep_waiting = ENDPOINT_MAX;
                        rx_unblock = true;
                }
        }

        spin_unlock_bh(&target->rx_lock);

        if (rx_unblock && !(target->htc_flags & HTC_OP_STATE_STOPPING))
                /* TODO : implement a buffer threshold count? */
                ath6kl_hif_rx_control(target->dev, true);

        return status;
}

static void ath6kl_htc_mbox_flush_rx_buf(struct htc_target *target)
{
        struct htc_endpoint *endpoint;
        struct htc_packet *packet, *tmp_pkt;
        int i;

        for (i = ENDPOINT_0; i < ENDPOINT_MAX; i++) {
                endpoint = &target->endpoint[i];
                if (!endpoint->svc_id)
                        /* not in use.. */
                        continue;

                spin_lock_bh(&target->rx_lock);
                list_for_each_entry_safe(packet, tmp_pkt,
                                         &endpoint->rx_bufq, list) {
                        list_del(&packet->list);
                        spin_unlock_bh(&target->rx_lock);
                        ath6kl_dbg(ATH6KL_DBG_HTC,
                                   "htc rx flush pkt 0x%p  len %d  ep %d\n",
                                   packet, packet->buf_len,
                                   packet->endpoint);
                        /*
                         * packets in rx_bufq of endpoint 0 have originally
                         * been queued from target->free_ctrl_rxbuf where
                         * packet and packet->buf_start are allocated
                         * separately using kmalloc(). For other endpoint
                         * rx_bufq, it is allocated as skb where packet is
                         * skb->head. Take care of this difference while freeing
                         * the memory.
                         */
                        if (packet->endpoint == ENDPOINT_0) {
                                kfree(packet->buf_start);
                                kfree(packet);
                        } else {
                                dev_kfree_skb(packet->pkt_cntxt);
                        }
                        spin_lock_bh(&target->rx_lock);
                }
                spin_unlock_bh(&target->rx_lock);
        }
}

static int ath6kl_htc_mbox_conn_service(struct htc_target *target,
                            struct htc_service_connect_req *conn_req,
                            struct htc_service_connect_resp *conn_resp)
{
        struct htc_packet *rx_pkt = NULL;
        struct htc_packet *tx_pkt = NULL;
        struct htc_conn_service_resp *resp_msg;
        struct htc_conn_service_msg *conn_msg;
        struct htc_endpoint *endpoint;
        enum htc_endpoint_id assigned_ep = ENDPOINT_MAX;
        unsigned int max_msg_sz = 0;
        int status = 0;
        u16 msg_id;

        ath6kl_dbg(ATH6KL_DBG_HTC,
                   "htc connect service target 0x%p service id 0x%x\n",
                   target, conn_req->svc_id);

        if (conn_req->svc_id == HTC_CTRL_RSVD_SVC) {
                /* special case for pseudo control service */
                assigned_ep = ENDPOINT_0;
                max_msg_sz = HTC_MAX_CTRL_MSG_LEN;
        } else {
                /* allocate a packet to send to the target */
                tx_pkt = htc_get_control_buf(target, true);

                if (!tx_pkt)
                        return -ENOMEM;

                conn_msg = (struct htc_conn_service_msg *)tx_pkt->buf;
                memset(conn_msg, 0, sizeof(*conn_msg));
                conn_msg->msg_id = cpu_to_le16(HTC_MSG_CONN_SVC_ID);
                conn_msg->svc_id = cpu_to_le16(conn_req->svc_id);
                conn_msg->conn_flags = cpu_to_le16(conn_req->conn_flags);

                set_htc_pkt_info(tx_pkt, NULL, (u8 *) conn_msg,
                                 sizeof(*conn_msg) + conn_msg->svc_meta_len,
                                 ENDPOINT_0, HTC_SERVICE_TX_PACKET_TAG);

                /* we want synchronous operation */
                tx_pkt->completion = NULL;
                ath6kl_htc_tx_prep_pkt(tx_pkt, 0, 0, 0);
                status = ath6kl_htc_tx_issue(target, tx_pkt);

                if (status)
                        goto fail_tx;

                /* wait for response */
                rx_pkt = htc_wait_for_ctrl_msg(target);

                if (!rx_pkt) {
                        status = -ENOMEM;
                        goto fail_tx;
                }

                resp_msg = (struct htc_conn_service_resp *)rx_pkt->buf;
                msg_id = le16_to_cpu(resp_msg->msg_id);

                if ((msg_id != HTC_MSG_CONN_SVC_RESP_ID) ||
                    (rx_pkt->act_len < sizeof(*resp_msg))) {
                        status = -ENOMEM;
                        goto fail_tx;
                }

                conn_resp->resp_code = resp_msg->status;
                /* check response status */
                if (resp_msg->status != HTC_SERVICE_SUCCESS) {
                        ath6kl_err("target failed service 0x%X connect request (status:%d)\n",
                                   resp_msg->svc_id, resp_msg->status);
                        status = -ENOMEM;
                        goto fail_tx;
                }

                assigned_ep = (enum htc_endpoint_id)resp_msg->eid;
                max_msg_sz = le16_to_cpu(resp_msg->max_msg_sz);
        }

        if (WARN_ON_ONCE(assigned_ep == ENDPOINT_UNUSED ||
                         assigned_ep >= ENDPOINT_MAX || !max_msg_sz)) {
                status = -ENOMEM;
                goto fail_tx;
        }

        endpoint = &target->endpoint[assigned_ep];
        endpoint->eid = assigned_ep;
        if (endpoint->svc_id) {
                status = -ENOMEM;
                goto fail_tx;
        }

        /* return assigned endpoint to caller */
        conn_resp->endpoint = assigned_ep;
        conn_resp->len_max = max_msg_sz;

        /* setup the endpoint */

        /* this marks the endpoint in use */
        endpoint->svc_id = conn_req->svc_id;

        endpoint->max_txq_depth = conn_req->max_txq_depth;
        endpoint->len_max = max_msg_sz;
        endpoint->ep_cb = conn_req->ep_cb;
        endpoint->cred_dist.svc_id = conn_req->svc_id;
        endpoint->cred_dist.htc_ep = endpoint;
        endpoint->cred_dist.endpoint = assigned_ep;
        endpoint->cred_dist.cred_sz = target->tgt_cred_sz;

        switch (endpoint->svc_id) {
        case WMI_DATA_BK_SVC:
                endpoint->tx_drop_packet_threshold = MAX_DEF_COOKIE_NUM / 3;
                break;
        default:
                endpoint->tx_drop_packet_threshold = MAX_HI_COOKIE_NUM;
                break;
        }

        if (conn_req->max_rxmsg_sz) {
                /*
                 * Override cred_per_msg calculation, this optimizes
                 * the credit-low indications since the host will actually
                 * issue smaller messages in the Send path.
                 */
                if (conn_req->max_rxmsg_sz > max_msg_sz) {
                        status = -ENOMEM;
                        goto fail_tx;
                }
                endpoint->cred_dist.cred_per_msg =
                    conn_req->max_rxmsg_sz / target->tgt_cred_sz;
        } else
                endpoint->cred_dist.cred_per_msg =
                    max_msg_sz / target->tgt_cred_sz;

        if (!endpoint->cred_dist.cred_per_msg)
                endpoint->cred_dist.cred_per_msg = 1;

        /* save local connection flags */
        endpoint->conn_flags = conn_req->flags;

fail_tx:
        if (tx_pkt)
                htc_reclaim_txctrl_buf(target, tx_pkt);

        if (rx_pkt) {
                htc_rxpkt_reset(rx_pkt);
                reclaim_rx_ctrl_buf(target, rx_pkt);
        }

        return status;
}

static void reset_ep_state(struct htc_target *target)
{
        struct htc_endpoint *endpoint;
        int i;

        for (i = ENDPOINT_0; i < ENDPOINT_MAX; i++) {
                endpoint = &target->endpoint[i];
                memset(&endpoint->cred_dist, 0, sizeof(endpoint->cred_dist));
                endpoint->svc_id = 0;
                endpoint->len_max = 0;
                endpoint->max_txq_depth = 0;
                memset(&endpoint->ep_st, 0,
                       sizeof(endpoint->ep_st));
                INIT_LIST_HEAD(&endpoint->rx_bufq);
                INIT_LIST_HEAD(&endpoint->txq);
                endpoint->target = target;
        }

        /* reset distribution list */
        /* FIXME: free existing entries */
        INIT_LIST_HEAD(&target->cred_dist_list);
}

static int ath6kl_htc_mbox_get_rxbuf_num(struct htc_target *target,
                             enum htc_endpoint_id endpoint)
{
        int num;

        spin_lock_bh(&target->rx_lock);
        num = get_queue_depth(&(target->endpoint[endpoint].rx_bufq));
        spin_unlock_bh(&target->rx_lock);
        return num;
}

static void htc_setup_msg_bndl(struct htc_target *target)
{
        /* limit what HTC can handle */
        target->msg_per_bndl_max = min(HTC_HOST_MAX_MSG_PER_BUNDLE,
                                       target->msg_per_bndl_max);

        if (ath6kl_hif_enable_scatter(target->dev->ar)) {
                target->msg_per_bndl_max = 0;
                return;
        }

        /* limit bundle what the device layer can handle */
        target->msg_per_bndl_max = min(target->max_scat_entries,
                                       target->msg_per_bndl_max);

        ath6kl_dbg(ATH6KL_DBG_BOOT,
                   "htc bundling allowed msg_per_bndl_max %d\n",
                   target->msg_per_bndl_max);

        /* Max rx bundle size is limited by the max tx bundle size */
        target->max_rx_bndl_sz = target->max_xfer_szper_scatreq;
        /* Max tx bundle size if limited by the extended mbox address range */
        target->max_tx_bndl_sz = min(HIF_MBOX0_EXT_WIDTH,
                                     target->max_xfer_szper_scatreq);

        ath6kl_dbg(ATH6KL_DBG_BOOT, "htc max_rx_bndl_sz %d max_tx_bndl_sz %d\n",
                   target->max_rx_bndl_sz, target->max_tx_bndl_sz);

        if (target->max_tx_bndl_sz)
                /* tx_bndl_mask is enabled per AC, each has 1 bit */
                target->tx_bndl_mask = (1 << WMM_NUM_AC) - 1;

        if (target->max_rx_bndl_sz)
                target->rx_bndl_enable = true;

        if ((target->tgt_cred_sz % target->block_sz) != 0) {
                ath6kl_warn("credit size: %d is not block aligned! Disabling send bundling\n",
                            target->tgt_cred_sz);

                /*
                 * Disallow send bundling since the credit size is
                 * not aligned to a block size the I/O block
                 * padding will spill into the next credit buffer
                 * which is fatal.
                 */
                target->tx_bndl_mask = 0;
        }
}

static int ath6kl_htc_mbox_wait_target(struct htc_target *target)
{
        struct htc_packet *packet = NULL;
        struct htc_ready_ext_msg *rdy_msg;
        struct htc_service_connect_req connect;
        struct htc_service_connect_resp resp;
        int status;

        /* we should be getting 1 control message that the target is ready */
        packet = htc_wait_for_ctrl_msg(target);

        if (!packet)
                return -ENOMEM;

        /* we controlled the buffer creation so it's properly aligned */
        rdy_msg = (struct htc_ready_ext_msg *)packet->buf;

        if ((le16_to_cpu(rdy_msg->ver2_0_info.msg_id) != HTC_MSG_READY_ID) ||
            (packet->act_len < sizeof(struct htc_ready_msg))) {
                status = -ENOMEM;
                goto fail_wait_target;
        }

        if (!rdy_msg->ver2_0_info.cred_cnt || !rdy_msg->ver2_0_info.cred_sz) {
                status = -ENOMEM;
                goto fail_wait_target;
        }

        target->tgt_creds = le16_to_cpu(rdy_msg->ver2_0_info.cred_cnt);
        target->tgt_cred_sz = le16_to_cpu(rdy_msg->ver2_0_info.cred_sz);

        ath6kl_dbg(ATH6KL_DBG_BOOT,
                   "htc target ready credits %d size %d\n",
                   target->tgt_creds, target->tgt_cred_sz);

        /* check if this is an extended ready message */
        if (packet->act_len >= sizeof(struct htc_ready_ext_msg)) {
                /* this is an extended message */
                target->htc_tgt_ver = rdy_msg->htc_ver;
                target->msg_per_bndl_max = rdy_msg->msg_per_htc_bndl;
        } else {
                /* legacy */
                target->htc_tgt_ver = HTC_VERSION_2P0;
                target->msg_per_bndl_max = 0;
        }

        ath6kl_dbg(ATH6KL_DBG_BOOT, "htc using protocol %s (%d)\n",
                   (target->htc_tgt_ver == HTC_VERSION_2P0) ? "2.0" : ">= 2.1",
                   target->htc_tgt_ver);

        if (target->msg_per_bndl_max > 0)
                htc_setup_msg_bndl(target);

        /* setup our pseudo HTC control endpoint connection */
        memset(&connect, 0, sizeof(connect));
        memset(&resp, 0, sizeof(resp));
        connect.ep_cb.rx = htc_ctrl_rx;
        connect.ep_cb.rx_refill = NULL;
        connect.ep_cb.tx_full = NULL;
        connect.max_txq_depth = NUM_CONTROL_BUFFERS;
        connect.svc_id = HTC_CTRL_RSVD_SVC;

        /* connect fake service */
        status = ath6kl_htc_mbox_conn_service((void *)target, &connect, &resp);

        if (status)
                /*
                 * FIXME: this call doesn't make sense, the caller should
                 * call ath6kl_htc_mbox_cleanup() when it wants remove htc
                 */
                ath6kl_hif_cleanup_scatter(target->dev->ar);

fail_wait_target:
        if (packet) {
                htc_rxpkt_reset(packet);
                reclaim_rx_ctrl_buf(target, packet);
        }

        return status;
}

/*
 * Start HTC, enable interrupts and let the target know
 * host has finished setup.
 */
static int ath6kl_htc_mbox_start(struct htc_target *target)
{
        struct htc_packet *packet;
        int status;

        memset(&target->dev->irq_proc_reg, 0,
               sizeof(target->dev->irq_proc_reg));

        /* Disable interrupts at the chip level */
        ath6kl_hif_disable_intrs(target->dev);

        target->htc_flags = 0;
        target->rx_st_flags = 0;

        /* Push control receive buffers into htc control endpoint */
        while ((packet = htc_get_control_buf(target, false)) != NULL) {
                status = htc_add_rxbuf(target, packet);
                if (status)
                        return status;
        }

        /* NOTE: the first entry in the distribution list is ENDPOINT_0 */
        ath6kl_credit_init(target->credit_info, &target->cred_dist_list,
                           target->tgt_creds);

        dump_cred_dist_stats(target);

        /* Indicate to the target of the setup completion */
        status = htc_setup_tx_complete(target);

        if (status)
                return status;

        /* unmask interrupts */
        status = ath6kl_hif_unmask_intrs(target->dev);

        if (status)
                ath6kl_htc_mbox_stop(target);

        return status;
}

static int ath6kl_htc_reset(struct htc_target *target)
{
        u32 block_size, ctrl_bufsz;
        struct htc_packet *packet;
        int i;

        reset_ep_state(target);

        block_size = target->dev->ar->mbox_info.block_size;

        ctrl_bufsz = (block_size > HTC_MAX_CTRL_MSG_LEN) ?
                      (block_size + HTC_HDR_LENGTH) :
                      (HTC_MAX_CTRL_MSG_LEN + HTC_HDR_LENGTH);

        for (i = 0; i < NUM_CONTROL_BUFFERS; i++) {
                packet = kzalloc_obj(*packet);
                if (!packet)
                        return -ENOMEM;

                packet->buf_start = kzalloc(ctrl_bufsz, GFP_KERNEL);
                if (!packet->buf_start) {
                        kfree(packet);
                        return -ENOMEM;
                }

                packet->buf_len = ctrl_bufsz;
                if (i < NUM_CONTROL_RX_BUFFERS) {
                        packet->act_len = 0;
                        packet->buf = packet->buf_start;
                        packet->endpoint = ENDPOINT_0;
                        list_add_tail(&packet->list, &target->free_ctrl_rxbuf);
                } else {
                        list_add_tail(&packet->list, &target->free_ctrl_txbuf);
                }
        }

        return 0;
}

/* htc_stop: stop interrupt reception, and flush all queued buffers */
static void ath6kl_htc_mbox_stop(struct htc_target *target)
{
        spin_lock_bh(&target->htc_lock);
        target->htc_flags |= HTC_OP_STATE_STOPPING;
        spin_unlock_bh(&target->htc_lock);

        /*
         * Masking interrupts is a synchronous operation, when this
         * function returns all pending HIF I/O has completed, we can
         * safely flush the queues.
         */
        ath6kl_hif_mask_intrs(target->dev);

        ath6kl_htc_flush_txep_all(target);

        ath6kl_htc_mbox_flush_rx_buf(target);

        ath6kl_htc_reset(target);
}

static void *ath6kl_htc_mbox_create(struct ath6kl *ar)
{
        struct htc_target *target = NULL;
        int status = 0;

        target = kzalloc_obj(*target);
        if (!target) {
                ath6kl_err("unable to allocate memory\n");
                return NULL;
        }

        target->dev = kzalloc_obj(*target->dev);
        if (!target->dev) {
                ath6kl_err("unable to allocate memory\n");
                kfree(target);
                return NULL;
        }

        spin_lock_init(&target->htc_lock);
        spin_lock_init(&target->rx_lock);
        spin_lock_init(&target->tx_lock);

        INIT_LIST_HEAD(&target->free_ctrl_txbuf);
        INIT_LIST_HEAD(&target->free_ctrl_rxbuf);
        INIT_LIST_HEAD(&target->cred_dist_list);

        target->dev->ar = ar;
        target->dev->htc_cnxt = target;
        target->ep_waiting = ENDPOINT_MAX;

        status = ath6kl_hif_setup(target->dev);
        if (status)
                goto err_htc_cleanup;

        status = ath6kl_htc_reset(target);
        if (status)
                goto err_htc_cleanup;

        return target;

err_htc_cleanup:
        ath6kl_htc_mbox_cleanup(target);

        return NULL;
}

/* cleanup the HTC instance */
static void ath6kl_htc_mbox_cleanup(struct htc_target *target)
{
        struct htc_packet *packet, *tmp_packet;

        ath6kl_hif_cleanup_scatter(target->dev->ar);

        list_for_each_entry_safe(packet, tmp_packet,
                                 &target->free_ctrl_txbuf, list) {
                list_del(&packet->list);
                kfree(packet->buf_start);
                kfree(packet);
        }

        list_for_each_entry_safe(packet, tmp_packet,
                                 &target->free_ctrl_rxbuf, list) {
                list_del(&packet->list);
                kfree(packet->buf_start);
                kfree(packet);
        }

        kfree(target->dev);
        kfree(target);
}

static const struct ath6kl_htc_ops ath6kl_htc_mbox_ops = {
        .create = ath6kl_htc_mbox_create,
        .wait_target = ath6kl_htc_mbox_wait_target,
        .start = ath6kl_htc_mbox_start,
        .conn_service = ath6kl_htc_mbox_conn_service,
        .tx = ath6kl_htc_mbox_tx,
        .stop = ath6kl_htc_mbox_stop,
        .cleanup = ath6kl_htc_mbox_cleanup,
        .flush_txep = ath6kl_htc_mbox_flush_txep,
        .flush_rx_buf = ath6kl_htc_mbox_flush_rx_buf,
        .activity_changed = ath6kl_htc_mbox_activity_changed,
        .get_rxbuf_num = ath6kl_htc_mbox_get_rxbuf_num,
        .add_rxbuf_multiple = ath6kl_htc_mbox_add_rxbuf_multiple,
        .credit_setup = ath6kl_htc_mbox_credit_setup,
};

void ath6kl_htc_mbox_attach(struct ath6kl *ar)
{
        ar->htc_ops = &ath6kl_htc_mbox_ops;
}