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

#include "core.h"
#include "hif.h"
#include "debug.h"

/********/
/* Send */
/********/

static inline void ath10k_htc_send_complete_check(struct ath10k_htc_ep *ep,
                                                  int force)
{
        /*
         * Check whether HIF has any prior sends that have finished,
         * have not had the post-processing done.
         */
        ath10k_hif_send_complete_check(ep->htc->ar, ep->ul_pipe_id, force);
}

static void ath10k_htc_control_tx_complete(struct ath10k *ar,
                                           struct sk_buff *skb)
{
        kfree_skb(skb);
}

static struct sk_buff *ath10k_htc_build_tx_ctrl_skb(void *ar)
{
        struct sk_buff *skb;
        struct ath10k_skb_cb *skb_cb;

        skb = dev_alloc_skb(ATH10K_HTC_CONTROL_BUFFER_SIZE);
        if (!skb) {
                ath10k_warn("Unable to allocate ctrl skb\n");
                return NULL;
        }

        skb_reserve(skb, 20); /* FIXME: why 20 bytes? */
        WARN_ONCE((unsigned long)skb->data & 3, "unaligned skb");

        skb_cb = ATH10K_SKB_CB(skb);
        memset(skb_cb, 0, sizeof(*skb_cb));

        ath10k_dbg(ATH10K_DBG_HTC, "%s: skb %p\n", __func__, skb);
        return skb;
}

static inline void ath10k_htc_restore_tx_skb(struct ath10k_htc *htc,
                                             struct sk_buff *skb)
{
        ath10k_skb_unmap(htc->ar->dev, skb);
        skb_pull(skb, sizeof(struct ath10k_htc_hdr));
}

static void ath10k_htc_notify_tx_completion(struct ath10k_htc_ep *ep,
                                            struct sk_buff *skb)
{
        ath10k_dbg(ATH10K_DBG_HTC, "%s: ep %d skb %p\n", __func__,
                   ep->eid, skb);

        ath10k_htc_restore_tx_skb(ep->htc, skb);

        if (!ep->ep_ops.ep_tx_complete) {
                ath10k_warn("no tx handler for eid %d\n", ep->eid);
                dev_kfree_skb_any(skb);
                return;
        }

        ep->ep_ops.ep_tx_complete(ep->htc->ar, skb);
}

/* assumes tx_lock is held */
static bool ath10k_htc_ep_need_credit_update(struct ath10k_htc_ep *ep)
{
        if (!ep->tx_credit_flow_enabled)
                return false;
        if (ep->tx_credits >= ep->tx_credits_per_max_message)
                return false;

        ath10k_dbg(ATH10K_DBG_HTC, "HTC: endpoint %d needs credit update\n",
                   ep->eid);
        return true;
}

static void ath10k_htc_prepare_tx_skb(struct ath10k_htc_ep *ep,
                                      struct sk_buff *skb)
{
        struct ath10k_htc_hdr *hdr;

        hdr = (struct ath10k_htc_hdr *)skb->data;
        memset(hdr, 0, sizeof(*hdr));

        hdr->eid = ep->eid;
        hdr->len = __cpu_to_le16(skb->len - sizeof(*hdr));

        spin_lock_bh(&ep->htc->tx_lock);
        hdr->seq_no = ep->seq_no++;

        if (ath10k_htc_ep_need_credit_update(ep))
                hdr->flags |= ATH10K_HTC_FLAG_NEED_CREDIT_UPDATE;

        spin_unlock_bh(&ep->htc->tx_lock);
}

static int ath10k_htc_issue_skb(struct ath10k_htc *htc,
                                struct ath10k_htc_ep *ep,
                                struct sk_buff *skb,
                                u8 credits)
{
        struct ath10k_skb_cb *skb_cb = ATH10K_SKB_CB(skb);
        int ret;

        ath10k_dbg(ATH10K_DBG_HTC, "%s: ep %d skb %p\n", __func__,
                   ep->eid, skb);

        ath10k_htc_prepare_tx_skb(ep, skb);

        ret = ath10k_skb_map(htc->ar->dev, skb);
        if (ret)
                goto err;

        ret = ath10k_hif_send_head(htc->ar,
                                   ep->ul_pipe_id,
                                   ep->eid,
                                   skb->len,
                                   skb);
        if (unlikely(ret))
                goto err;

        return 0;
err:
        ath10k_warn("HTC issue failed: %d\n", ret);

        spin_lock_bh(&htc->tx_lock);
        ep->tx_credits += credits;
        spin_unlock_bh(&htc->tx_lock);

        /* this is the simplest way to handle out-of-resources for non-credit
         * based endpoints. credit based endpoints can still get -ENOSR, but
         * this is highly unlikely as credit reservation should prevent that */
        if (ret == -ENOSR) {
                spin_lock_bh(&htc->tx_lock);
                __skb_queue_head(&ep->tx_queue, skb);
                spin_unlock_bh(&htc->tx_lock);

                return ret;
        }

        skb_cb->is_aborted = true;
        ath10k_htc_notify_tx_completion(ep, skb);

        return ret;
}

static struct sk_buff *ath10k_htc_get_skb_credit_based(struct ath10k_htc *htc,
                                                       struct ath10k_htc_ep *ep,
                                                       u8 *credits)
{
        struct sk_buff *skb;
        struct ath10k_skb_cb *skb_cb;
        int credits_required;
        int remainder;
        unsigned int transfer_len;

        lockdep_assert_held(&htc->tx_lock);

        skb = __skb_dequeue(&ep->tx_queue);
        if (!skb)
                return NULL;

        skb_cb = ATH10K_SKB_CB(skb);
        transfer_len = skb->len;

        if (likely(transfer_len <= htc->target_credit_size)) {
                credits_required = 1;
        } else {
                /* figure out how many credits this message requires */
                credits_required = transfer_len / htc->target_credit_size;
                remainder = transfer_len % htc->target_credit_size;

                if (remainder)
                        credits_required++;
        }

        ath10k_dbg(ATH10K_DBG_HTC, "Credits required %d got %d\n",
                   credits_required, ep->tx_credits);

        if (ep->tx_credits < credits_required) {
                __skb_queue_head(&ep->tx_queue, skb);
                return NULL;
        }

        ep->tx_credits -= credits_required;
        *credits = credits_required;
        return skb;
}

static void ath10k_htc_send_work(struct work_struct *work)
{
        struct ath10k_htc_ep *ep = container_of(work,
                                        struct ath10k_htc_ep, send_work);
        struct ath10k_htc *htc = ep->htc;
        struct sk_buff *skb;
        u8 credits = 0;
        int ret;

        while (true) {
                if (ep->ul_is_polled)
                        ath10k_htc_send_complete_check(ep, 0);

                spin_lock_bh(&htc->tx_lock);
                if (ep->tx_credit_flow_enabled)
                        skb = ath10k_htc_get_skb_credit_based(htc, ep,
                                                              &credits);
                else
                        skb = __skb_dequeue(&ep->tx_queue);
                spin_unlock_bh(&htc->tx_lock);

                if (!skb)
                        break;

                ret = ath10k_htc_issue_skb(htc, ep, skb, credits);
                if (ret == -ENOSR)
                        break;
        }
}

int ath10k_htc_send(struct ath10k_htc *htc,
                    enum ath10k_htc_ep_id eid,
                    struct sk_buff *skb)
{
        struct ath10k_htc_ep *ep = &htc->endpoint[eid];

        if (eid >= ATH10K_HTC_EP_COUNT) {
                ath10k_warn("Invalid endpoint id: %d\n", eid);
                return -ENOENT;
        }

        skb_push(skb, sizeof(struct ath10k_htc_hdr));

        spin_lock_bh(&htc->tx_lock);
        __skb_queue_tail(&ep->tx_queue, skb);
        spin_unlock_bh(&htc->tx_lock);

        queue_work(htc->ar->workqueue, &ep->send_work);
        return 0;
}

static int ath10k_htc_tx_completion_handler(struct ath10k *ar,
                                            struct sk_buff *skb,
                                            unsigned int eid)
{
        struct ath10k_htc *htc = ar->htc;
        struct ath10k_htc_ep *ep = &htc->endpoint[eid];
        bool stopping;

        ath10k_htc_notify_tx_completion(ep, skb);
        /* the skb now belongs to the completion handler */

        spin_lock_bh(&htc->tx_lock);
        stopping = htc->stopping;
        spin_unlock_bh(&htc->tx_lock);

        if (!ep->tx_credit_flow_enabled && !stopping)
                /*
                 * note: when using TX credit flow, the re-checking of
                 * queues happens when credits flow back from the target.
                 * in the non-TX credit case, we recheck after the packet
                 * completes
                 */
                queue_work(ar->workqueue, &ep->send_work);

        return 0;
}

/* flush endpoint TX queue */
static void ath10k_htc_flush_endpoint_tx(struct ath10k_htc *htc,
                                         struct ath10k_htc_ep *ep)
{
        struct sk_buff *skb;
        struct ath10k_skb_cb *skb_cb;

        spin_lock_bh(&htc->tx_lock);
        for (;;) {
                skb = __skb_dequeue(&ep->tx_queue);
                if (!skb)
                        break;

                skb_cb = ATH10K_SKB_CB(skb);
                skb_cb->is_aborted = true;
                ath10k_htc_notify_tx_completion(ep, skb);
        }
        spin_unlock_bh(&htc->tx_lock);

        cancel_work_sync(&ep->send_work);
}

/***********/
/* Receive */
/***********/

static void
ath10k_htc_process_credit_report(struct ath10k_htc *htc,
                                 const struct ath10k_htc_credit_report *report,
                                 int len,
                                 enum ath10k_htc_ep_id eid)
{
        struct ath10k_htc_ep *ep;
        int i, n_reports;

        if (len % sizeof(*report))
                ath10k_warn("Uneven credit report len %d", len);

        n_reports = len / sizeof(*report);

        spin_lock_bh(&htc->tx_lock);
        for (i = 0; i < n_reports; i++, report++) {
                if (report->eid >= ATH10K_HTC_EP_COUNT)
                        break;

                ath10k_dbg(ATH10K_DBG_HTC, "ep %d got %d credits\n",
                           report->eid, report->credits);

                ep = &htc->endpoint[report->eid];
                ep->tx_credits += report->credits;

                if (ep->tx_credits && !skb_queue_empty(&ep->tx_queue))
                        queue_work(htc->ar->workqueue, &ep->send_work);
        }
        spin_unlock_bh(&htc->tx_lock);
}

static int ath10k_htc_process_trailer(struct ath10k_htc *htc,
                                      u8 *buffer,
                                      int length,
                                      enum ath10k_htc_ep_id src_eid)
{
        int status = 0;
        struct ath10k_htc_record *record;
        u8 *orig_buffer;
        int orig_length;
        size_t len;

        orig_buffer = buffer;
        orig_length = length;

        while (length > 0) {
                record = (struct ath10k_htc_record *)buffer;

                if (length < sizeof(record->hdr)) {
                        status = -EINVAL;
                        break;
                }

                if (record->hdr.len > length) {
                        /* no room left in buffer for record */
                        ath10k_warn("Invalid record length: %d\n",
                                    record->hdr.len);
                        status = -EINVAL;
                        break;
                }

                switch (record->hdr.id) {
                case ATH10K_HTC_RECORD_CREDITS:
                        len = sizeof(struct ath10k_htc_credit_report);
                        if (record->hdr.len < len) {
                                ath10k_warn("Credit report too long\n");
                                status = -EINVAL;
                                break;
                        }
                        ath10k_htc_process_credit_report(htc,
                                                         record->credit_report,
                                                         record->hdr.len,
                                                         src_eid);
                        break;
                default:
                        ath10k_warn("Unhandled record: id:%d length:%d\n",
                                    record->hdr.id, record->hdr.len);
                        break;
                }

                if (status)
                        break;

                /* multiple records may be present in a trailer */
                buffer += sizeof(record->hdr) + record->hdr.len;
                length -= sizeof(record->hdr) + record->hdr.len;
        }

        if (status)
                ath10k_dbg_dump(ATH10K_DBG_HTC, "htc rx bad trailer", "",
                                orig_buffer, orig_length);

        return status;
}

static int ath10k_htc_rx_completion_handler(struct ath10k *ar,
                                            struct sk_buff *skb,
                                            u8 pipe_id)
{
        int status = 0;
        struct ath10k_htc *htc = ar->htc;
        struct ath10k_htc_hdr *hdr;
        struct ath10k_htc_ep *ep;
        u16 payload_len;
        u32 trailer_len = 0;
        size_t min_len;
        u8 eid;
        bool trailer_present;

        hdr = (struct ath10k_htc_hdr *)skb->data;
        skb_pull(skb, sizeof(*hdr));

        eid = hdr->eid;

        if (eid >= ATH10K_HTC_EP_COUNT) {
                ath10k_warn("HTC Rx: invalid eid %d\n", eid);
                ath10k_dbg_dump(ATH10K_DBG_HTC, "htc bad header", "",
                                hdr, sizeof(*hdr));
                status = -EINVAL;
                goto out;
        }

        ep = &htc->endpoint[eid];

        /*
         * If this endpoint that received a message from the target has
         * a to-target HIF pipe whose send completions are polled rather
         * than interrupt-driven, this is a good point to ask HIF to check
         * whether it has any completed sends to handle.
         */
        if (ep->ul_is_polled)
                ath10k_htc_send_complete_check(ep, 1);

        payload_len = __le16_to_cpu(hdr->len);

        if (payload_len + sizeof(*hdr) > ATH10K_HTC_MAX_LEN) {
                ath10k_warn("HTC rx frame too long, len: %zu\n",
                            payload_len + sizeof(*hdr));
                ath10k_dbg_dump(ATH10K_DBG_HTC, "htc bad rx pkt len", "",
                                hdr, sizeof(*hdr));
                status = -EINVAL;
                goto out;
        }

        if (skb->len < payload_len) {
                ath10k_dbg(ATH10K_DBG_HTC,
                           "HTC Rx: insufficient length, got %d, expected %d\n",
                           skb->len, payload_len);
                ath10k_dbg_dump(ATH10K_DBG_HTC, "htc bad rx pkt len",
                                "", hdr, sizeof(*hdr));
                status = -EINVAL;
                goto out;
        }

        /* get flags to check for trailer */
        trailer_present = hdr->flags & ATH10K_HTC_FLAG_TRAILER_PRESENT;
        if (trailer_present) {
                u8 *trailer;

                trailer_len = hdr->trailer_len;
                min_len = sizeof(struct ath10k_ath10k_htc_record_hdr);

                if ((trailer_len < min_len) ||
                    (trailer_len > payload_len)) {
                        ath10k_warn("Invalid trailer length: %d\n",
                                    trailer_len);
                        status = -EPROTO;
                        goto out;
                }

                trailer = (u8 *)hdr;
                trailer += sizeof(*hdr);
                trailer += payload_len;
                trailer -= trailer_len;
                status = ath10k_htc_process_trailer(htc, trailer,
                                                    trailer_len, hdr->eid);
                if (status)
                        goto out;

                skb_trim(skb, skb->len - trailer_len);
        }

        if (((int)payload_len - (int)trailer_len) <= 0)
                /* zero length packet with trailer data, just drop these */
                goto out;

        if (eid == ATH10K_HTC_EP_0) {
                struct ath10k_htc_msg *msg = (struct ath10k_htc_msg *)skb->data;

                switch (__le16_to_cpu(msg->hdr.message_id)) {
                default:
                        /* handle HTC control message */
                        if (completion_done(&htc->ctl_resp)) {
                                /*
                                 * this is a fatal error, target should not be
                                 * sending unsolicited messages on the ep 0
                                 */
                                ath10k_warn("HTC rx ctrl still processing\n");
                                status = -EINVAL;
                                complete(&htc->ctl_resp);
                                goto out;
                        }

                        htc->control_resp_len =
                                min_t(int, skb->len,
                                      ATH10K_HTC_MAX_CTRL_MSG_LEN);

                        memcpy(htc->control_resp_buffer, skb->data,
                               htc->control_resp_len);

                        complete(&htc->ctl_resp);
                        break;
                case ATH10K_HTC_MSG_SEND_SUSPEND_COMPLETE:
                        htc->htc_ops.target_send_suspend_complete(ar);
                }
                goto out;
        }

        ath10k_dbg(ATH10K_DBG_HTC, "htc rx completion ep %d skb %p\n",
                   eid, skb);
        ep->ep_ops.ep_rx_complete(ar, skb);

        /* skb is now owned by the rx completion handler */
        skb = NULL;
out:
        kfree_skb(skb);

        return status;
}

static void ath10k_htc_control_rx_complete(struct ath10k *ar,
                                           struct sk_buff *skb)
{
        /* This is unexpected. FW is not supposed to send regular rx on this
         * endpoint. */
        ath10k_warn("unexpected htc rx\n");
        kfree_skb(skb);
}

/***************/
/* Init/Deinit */
/***************/

static const char *htc_service_name(enum ath10k_htc_svc_id id)
{
        switch (id) {
        case ATH10K_HTC_SVC_ID_RESERVED:
                return "Reserved";
        case ATH10K_HTC_SVC_ID_RSVD_CTRL:
                return "Control";
        case ATH10K_HTC_SVC_ID_WMI_CONTROL:
                return "WMI";
        case ATH10K_HTC_SVC_ID_WMI_DATA_BE:
                return "DATA BE";
        case ATH10K_HTC_SVC_ID_WMI_DATA_BK:
                return "DATA BK";
        case ATH10K_HTC_SVC_ID_WMI_DATA_VI:
                return "DATA VI";
        case ATH10K_HTC_SVC_ID_WMI_DATA_VO:
                return "DATA VO";
        case ATH10K_HTC_SVC_ID_NMI_CONTROL:
                return "NMI Control";
        case ATH10K_HTC_SVC_ID_NMI_DATA:
                return "NMI Data";
        case ATH10K_HTC_SVC_ID_HTT_DATA_MSG:
                return "HTT Data";
        case ATH10K_HTC_SVC_ID_TEST_RAW_STREAMS:
                return "RAW";
        }

        return "Unknown";
}

static void ath10k_htc_reset_endpoint_states(struct ath10k_htc *htc)
{
        struct ath10k_htc_ep *ep;
        int i;

        for (i = ATH10K_HTC_EP_0; i < ATH10K_HTC_EP_COUNT; i++) {
                ep = &htc->endpoint[i];
                ep->service_id = ATH10K_HTC_SVC_ID_UNUSED;
                ep->max_ep_message_len = 0;
                ep->max_tx_queue_depth = 0;
                ep->eid = i;
                skb_queue_head_init(&ep->tx_queue);
                ep->htc = htc;
                ep->tx_credit_flow_enabled = true;
                INIT_WORK(&ep->send_work, ath10k_htc_send_work);
        }
}

static void ath10k_htc_setup_target_buffer_assignments(struct ath10k_htc *htc)
{
        struct ath10k_htc_svc_tx_credits *entry;

        entry = &htc->service_tx_alloc[0];

        /*
         * for PCIE allocate all credists/HTC buffers to WMI.
         * no buffers are used/required for data. data always
         * remains on host.
         */
        entry++;
        entry->service_id = ATH10K_HTC_SVC_ID_WMI_CONTROL;
        entry->credit_allocation = htc->total_transmit_credits;
}

static u8 ath10k_htc_get_credit_allocation(struct ath10k_htc *htc,
                                           u16 service_id)
{
        u8 allocation = 0;
        int i;

        for (i = 0; i < ATH10K_HTC_EP_COUNT; i++) {
                if (htc->service_tx_alloc[i].service_id == service_id)
                        allocation =
                            htc->service_tx_alloc[i].credit_allocation;
        }

        return allocation;
}

int ath10k_htc_wait_target(struct ath10k_htc *htc)
{
        int status = 0;
        struct ath10k_htc_svc_conn_req conn_req;
        struct ath10k_htc_svc_conn_resp conn_resp;
        struct ath10k_htc_msg *msg;
        u16 message_id;
        u16 credit_count;
        u16 credit_size;

        INIT_COMPLETION(htc->ctl_resp);

        status = ath10k_hif_start(htc->ar);
        if (status) {
                ath10k_err("could not start HIF (%d)\n", status);
                goto err_start;
        }

        status = wait_for_completion_timeout(&htc->ctl_resp,
                                             ATH10K_HTC_WAIT_TIMEOUT_HZ);
        if (status <= 0) {
                if (status == 0)
                        status = -ETIMEDOUT;

                ath10k_err("ctl_resp never came in (%d)\n", status);
                goto err_target;
        }

        if (htc->control_resp_len < sizeof(msg->hdr) + sizeof(msg->ready)) {
                ath10k_err("Invalid HTC ready msg len:%d\n",
                           htc->control_resp_len);

                status = -ECOMM;
                goto err_target;
        }

        msg = (struct ath10k_htc_msg *)htc->control_resp_buffer;
        message_id   = __le16_to_cpu(msg->hdr.message_id);
        credit_count = __le16_to_cpu(msg->ready.credit_count);
        credit_size  = __le16_to_cpu(msg->ready.credit_size);

        if (message_id != ATH10K_HTC_MSG_READY_ID) {
                ath10k_err("Invalid HTC ready msg: 0x%x\n", message_id);
                status = -ECOMM;
                goto err_target;
        }

        htc->total_transmit_credits = credit_count;
        htc->target_credit_size = credit_size;

        ath10k_dbg(ATH10K_DBG_HTC,
                   "Target ready! transmit resources: %d size:%d\n",
                   htc->total_transmit_credits,
                   htc->target_credit_size);

        if ((htc->total_transmit_credits == 0) ||
            (htc->target_credit_size == 0)) {
                status = -ECOMM;
                ath10k_err("Invalid credit size received\n");
                goto err_target;
        }

        ath10k_htc_setup_target_buffer_assignments(htc);

        /* setup our pseudo HTC control endpoint connection */
        memset(&conn_req, 0, sizeof(conn_req));
        memset(&conn_resp, 0, sizeof(conn_resp));
        conn_req.ep_ops.ep_tx_complete = ath10k_htc_control_tx_complete;
        conn_req.ep_ops.ep_rx_complete = ath10k_htc_control_rx_complete;
        conn_req.max_send_queue_depth = ATH10K_NUM_CONTROL_TX_BUFFERS;
        conn_req.service_id = ATH10K_HTC_SVC_ID_RSVD_CTRL;

        /* connect fake service */
        status = ath10k_htc_connect_service(htc, &conn_req, &conn_resp);
        if (status) {
                ath10k_err("could not connect to htc service (%d)\n", status);
                goto err_target;
        }

        return 0;
err_target:
        ath10k_hif_stop(htc->ar);
err_start:
        return status;
}

int ath10k_htc_connect_service(struct ath10k_htc *htc,
                               struct ath10k_htc_svc_conn_req *conn_req,
                               struct ath10k_htc_svc_conn_resp *conn_resp)
{
        struct ath10k_htc_msg *msg;
        struct ath10k_htc_conn_svc *req_msg;
        struct ath10k_htc_conn_svc_response resp_msg_dummy;
        struct ath10k_htc_conn_svc_response *resp_msg = &resp_msg_dummy;
        enum ath10k_htc_ep_id assigned_eid = ATH10K_HTC_EP_COUNT;
        struct ath10k_htc_ep *ep;
        struct sk_buff *skb;
        unsigned int max_msg_size = 0;
        int length, status;
        bool disable_credit_flow_ctrl = false;
        u16 message_id, service_id, flags = 0;
        u8 tx_alloc = 0;

        /* special case for HTC pseudo control service */
        if (conn_req->service_id == ATH10K_HTC_SVC_ID_RSVD_CTRL) {
                disable_credit_flow_ctrl = true;
                assigned_eid = ATH10K_HTC_EP_0;
                max_msg_size = ATH10K_HTC_MAX_CTRL_MSG_LEN;
                memset(&resp_msg_dummy, 0, sizeof(resp_msg_dummy));
                goto setup;
        }

        tx_alloc = ath10k_htc_get_credit_allocation(htc,
                                                    conn_req->service_id);
        if (!tx_alloc)
                ath10k_warn("HTC Service %s does not allocate target credits\n",
                            htc_service_name(conn_req->service_id));

        skb = ath10k_htc_build_tx_ctrl_skb(htc->ar);
        if (!skb) {
                ath10k_err("Failed to allocate HTC packet\n");
                return -ENOMEM;
        }

        length = sizeof(msg->hdr) + sizeof(msg->connect_service);
        skb_put(skb, length);
        memset(skb->data, 0, length);

        msg = (struct ath10k_htc_msg *)skb->data;
        msg->hdr.message_id =
                __cpu_to_le16(ATH10K_HTC_MSG_CONNECT_SERVICE_ID);

        flags |= SM(tx_alloc, ATH10K_HTC_CONN_FLAGS_RECV_ALLOC);

        req_msg = &msg->connect_service;
        req_msg->flags = __cpu_to_le16(flags);
        req_msg->service_id = __cpu_to_le16(conn_req->service_id);

        /* Only enable credit flow control for WMI ctrl service */
        if (conn_req->service_id != ATH10K_HTC_SVC_ID_WMI_CONTROL) {
                flags |= ATH10K_HTC_CONN_FLAGS_DISABLE_CREDIT_FLOW_CTRL;
                disable_credit_flow_ctrl = true;
        }

        INIT_COMPLETION(htc->ctl_resp);

        status = ath10k_htc_send(htc, ATH10K_HTC_EP_0, skb);
        if (status) {
                kfree_skb(skb);
                return status;
        }

        /* wait for response */
        status = wait_for_completion_timeout(&htc->ctl_resp,
                                             ATH10K_HTC_CONN_SVC_TIMEOUT_HZ);
        if (status <= 0) {
                if (status == 0)
                        status = -ETIMEDOUT;
                ath10k_err("Service connect timeout: %d\n", status);
                return status;
        }

        /* we controlled the buffer creation, it's aligned */
        msg = (struct ath10k_htc_msg *)htc->control_resp_buffer;
        resp_msg = &msg->connect_service_response;
        message_id = __le16_to_cpu(msg->hdr.message_id);
        service_id = __le16_to_cpu(resp_msg->service_id);

        if ((message_id != ATH10K_HTC_MSG_CONNECT_SERVICE_RESP_ID) ||
            (htc->control_resp_len < sizeof(msg->hdr) +
             sizeof(msg->connect_service_response))) {
                ath10k_err("Invalid resp message ID 0x%x", message_id);
                return -EPROTO;
        }

        ath10k_dbg(ATH10K_DBG_HTC,
                   "HTC Service %s connect response: status: 0x%x, assigned ep: 0x%x\n",
                   htc_service_name(service_id),
                   resp_msg->status, resp_msg->eid);

        conn_resp->connect_resp_code = resp_msg->status;

        /* check response status */
        if (resp_msg->status != ATH10K_HTC_CONN_SVC_STATUS_SUCCESS) {
                ath10k_err("HTC Service %s connect request failed: 0x%x)\n",
                           htc_service_name(service_id),
                           resp_msg->status);
                return -EPROTO;
        }

        assigned_eid = (enum ath10k_htc_ep_id)resp_msg->eid;
        max_msg_size = __le16_to_cpu(resp_msg->max_msg_size);

setup:

        if (assigned_eid >= ATH10K_HTC_EP_COUNT)
                return -EPROTO;

        if (max_msg_size == 0)
                return -EPROTO;

        ep = &htc->endpoint[assigned_eid];
        ep->eid = assigned_eid;

        if (ep->service_id != ATH10K_HTC_SVC_ID_UNUSED)
                return -EPROTO;

        /* return assigned endpoint to caller */
        conn_resp->eid = assigned_eid;
        conn_resp->max_msg_len = __le16_to_cpu(resp_msg->max_msg_size);

        /* setup the endpoint */
        ep->service_id = conn_req->service_id;
        ep->max_tx_queue_depth = conn_req->max_send_queue_depth;
        ep->max_ep_message_len = __le16_to_cpu(resp_msg->max_msg_size);
        ep->tx_credits = tx_alloc;
        ep->tx_credit_size = htc->target_credit_size;
        ep->tx_credits_per_max_message = ep->max_ep_message_len /
                                         htc->target_credit_size;

        if (ep->max_ep_message_len % htc->target_credit_size)
                ep->tx_credits_per_max_message++;

        /* copy all the callbacks */
        ep->ep_ops = conn_req->ep_ops;

        status = ath10k_hif_map_service_to_pipe(htc->ar,
                                                ep->service_id,
                                                &ep->ul_pipe_id,
                                                &ep->dl_pipe_id,
                                                &ep->ul_is_polled,
                                                &ep->dl_is_polled);
        if (status)
                return status;

        ath10k_dbg(ATH10K_DBG_HTC,
                   "HTC service: %s UL pipe: %d DL pipe: %d eid: %d ready\n",
                   htc_service_name(ep->service_id), ep->ul_pipe_id,
                   ep->dl_pipe_id, ep->eid);

        ath10k_dbg(ATH10K_DBG_HTC,
                   "EP %d UL polled: %d, DL polled: %d\n",
                   ep->eid, ep->ul_is_polled, ep->dl_is_polled);

        if (disable_credit_flow_ctrl && ep->tx_credit_flow_enabled) {
                ep->tx_credit_flow_enabled = false;
                ath10k_dbg(ATH10K_DBG_HTC,
                           "HTC service: %s eid: %d TX flow control disabled\n",
                           htc_service_name(ep->service_id), assigned_eid);
        }

        return status;
}

struct sk_buff *ath10k_htc_alloc_skb(int size)
{
        struct sk_buff *skb;

        skb = dev_alloc_skb(size + sizeof(struct ath10k_htc_hdr));
        if (!skb) {
                ath10k_warn("could not allocate HTC tx skb\n");
                return NULL;
        }

        skb_reserve(skb, sizeof(struct ath10k_htc_hdr));

        /* FW/HTC requires 4-byte aligned streams */
        if (!IS_ALIGNED((unsigned long)skb->data, 4))
                ath10k_warn("Unaligned HTC tx skb\n");

        return skb;
}

int ath10k_htc_start(struct ath10k_htc *htc)
{
        struct sk_buff *skb;
        int status = 0;
        struct ath10k_htc_msg *msg;

        skb = ath10k_htc_build_tx_ctrl_skb(htc->ar);
        if (!skb)
                return -ENOMEM;

        skb_put(skb, sizeof(msg->hdr) + sizeof(msg->setup_complete_ext));
        memset(skb->data, 0, skb->len);

        msg = (struct ath10k_htc_msg *)skb->data;
        msg->hdr.message_id =
                __cpu_to_le16(ATH10K_HTC_MSG_SETUP_COMPLETE_EX_ID);

        ath10k_dbg(ATH10K_DBG_HTC, "HTC is using TX credit flow control\n");

        status = ath10k_htc_send(htc, ATH10K_HTC_EP_0, skb);
        if (status) {
                kfree_skb(skb);
                return status;
        }

        return 0;
}

/*
 * stop HTC communications, i.e. stop interrupt reception, and flush all
 * queued buffers
 */
void ath10k_htc_stop(struct ath10k_htc *htc)
{
        int i;
        struct ath10k_htc_ep *ep;

        spin_lock_bh(&htc->tx_lock);
        htc->stopping = true;
        spin_unlock_bh(&htc->tx_lock);

        for (i = ATH10K_HTC_EP_0; i < ATH10K_HTC_EP_COUNT; i++) {
                ep = &htc->endpoint[i];
                ath10k_htc_flush_endpoint_tx(htc, ep);
        }

        ath10k_hif_stop(htc->ar);
        ath10k_htc_reset_endpoint_states(htc);
}

/* registered target arrival callback from the HIF layer */
struct ath10k_htc *ath10k_htc_create(struct ath10k *ar,
                                     struct ath10k_htc_ops *htc_ops)
{
        struct ath10k_hif_cb htc_callbacks;
        struct ath10k_htc_ep *ep = NULL;
        struct ath10k_htc *htc = NULL;

        /* FIXME: use struct ath10k instead */
        htc = kzalloc(sizeof(struct ath10k_htc), GFP_KERNEL);
        if (!htc)
                return ERR_PTR(-ENOMEM);

        spin_lock_init(&htc->tx_lock);

        memcpy(&htc->htc_ops, htc_ops, sizeof(struct ath10k_htc_ops));

        ath10k_htc_reset_endpoint_states(htc);

        /* setup HIF layer callbacks */
        htc_callbacks.rx_completion = ath10k_htc_rx_completion_handler;
        htc_callbacks.tx_completion = ath10k_htc_tx_completion_handler;
        htc->ar = ar;

        /* Get HIF default pipe for HTC message exchange */
        ep = &htc->endpoint[ATH10K_HTC_EP_0];

        ath10k_hif_init(ar, &htc_callbacks);
        ath10k_hif_get_default_pipe(ar, &ep->ul_pipe_id, &ep->dl_pipe_id);

        init_completion(&htc->ctl_resp);

        return htc;
}

void ath10k_htc_destroy(struct ath10k_htc *htc)
{
        kfree(htc);
}