/*
 * Marvell Wireless LAN device driver: 802.11n Aggregation
 *
 * Copyright (C) 2011, Marvell International Ltd.
 *
 * This software file (the "File") is distributed by Marvell International
 * Ltd. under the terms of the GNU General Public License Version 2, June 1991
 * (the "License").  You may use, redistribute and/or modify this File in
 * accordance with the terms and conditions of the License, a copy of which
 * is available by writing to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA or on the
 * worldwide web at http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt.
 *
 * THE FILE IS DISTRIBUTED AS-IS, WITHOUT WARRANTY OF ANY KIND, AND THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE
 * ARE EXPRESSLY DISCLAIMED.  The License provides additional details about
 * this warranty disclaimer.
 */

#include "decl.h"
#include "ioctl.h"
#include "util.h"
#include "fw.h"
#include "main.h"
#include "wmm.h"
#include "11n.h"
#include "11n_aggr.h"

/*
 * Creates an AMSDU subframe for aggregation into one AMSDU packet.
 *
 * The resultant AMSDU subframe format is -
 *
 * +---- ~ -----+---- ~ ------+---- ~ -----+----- ~ -----+---- ~ -----+
 * |     DA     |     SA      |   Length   | SNAP header |   MSDU     |
 * | data[0..5] | data[6..11] |            |             | data[14..] |
 * +---- ~ -----+---- ~ ------+---- ~ -----+----- ~ -----+---- ~ -----+
 * <--6-bytes--> <--6-bytes--> <--2-bytes--><--8-bytes--> <--n-bytes-->
 *
 * This function also computes the amount of padding required to make the
 * buffer length multiple of 4 bytes.
 *
 * Data => |DA|SA|SNAP-TYPE|........    .|
 * MSDU => |DA|SA|Length|SNAP|......   ..|
 */
static int
mwifiex_11n_form_amsdu_pkt(struct sk_buff *skb_aggr,
                           struct sk_buff *skb_src, int *pad)

{
        int dt_offset;
        struct rfc_1042_hdr snap = {
                0xaa,           /* LLC DSAP */
                0xaa,           /* LLC SSAP */
                0x03,           /* LLC CTRL */
                {0x00, 0x00, 0x00},     /* SNAP OUI */
                0x0000          /* SNAP type */
                        /*
                         * This field will be overwritten
                         * later with ethertype
                         */
        };
        struct tx_packet_hdr *tx_header;

        tx_header = (void *)skb_put(skb_aggr, sizeof(*tx_header));

        /* Copy DA and SA */
        dt_offset = 2 * ETH_ALEN;
        memcpy(&tx_header->eth803_hdr, skb_src->data, dt_offset);

        /* Copy SNAP header */
        snap.snap_type = *(u16 *) ((u8 *)skb_src->data + dt_offset);
        dt_offset += sizeof(u16);

        memcpy(&tx_header->rfc1042_hdr, &snap, sizeof(struct rfc_1042_hdr));

        skb_pull(skb_src, dt_offset);

        /* Update Length field */
        tx_header->eth803_hdr.h_proto = htons(skb_src->len + LLC_SNAP_LEN);

        /* Add payload */
        memcpy(skb_put(skb_aggr, skb_src->len), skb_src->data, skb_src->len);

        /* Add padding for new MSDU to start from 4 byte boundary */
        *pad = (4 - ((unsigned long)skb_aggr->tail & 0x3)) % 4;

        return skb_aggr->len + *pad;
}

/*
 * Adds TxPD to AMSDU header.
 *
 * Each AMSDU packet will contain one TxPD at the beginning,
 * followed by multiple AMSDU subframes.
 */
static void
mwifiex_11n_form_amsdu_txpd(struct mwifiex_private *priv,
                            struct sk_buff *skb)
{
        struct txpd *local_tx_pd;

        skb_push(skb, sizeof(*local_tx_pd));

        local_tx_pd = (struct txpd *) skb->data;
        memset(local_tx_pd, 0, sizeof(struct txpd));

        /* Original priority has been overwritten */
        local_tx_pd->priority = (u8) skb->priority;
        local_tx_pd->pkt_delay_2ms =
                mwifiex_wmm_compute_drv_pkt_delay(priv, skb);
        local_tx_pd->bss_num = priv->bss_num;
        local_tx_pd->bss_type = priv->bss_type;
        /* Always zero as the data is followed by struct txpd */
        local_tx_pd->tx_pkt_offset = cpu_to_le16(sizeof(struct txpd));
        local_tx_pd->tx_pkt_type = cpu_to_le16(PKT_TYPE_AMSDU);
        local_tx_pd->tx_pkt_length = cpu_to_le16(skb->len -
                                                 sizeof(*local_tx_pd));

        if (local_tx_pd->tx_control == 0)
                /* TxCtrl set by user or default */
                local_tx_pd->tx_control = cpu_to_le32(priv->pkt_tx_ctrl);

        if (GET_BSS_ROLE(priv) == MWIFIEX_BSS_ROLE_STA &&
            priv->adapter->pps_uapsd_mode) {
                if (true == mwifiex_check_last_packet_indication(priv)) {
                        priv->adapter->tx_lock_flag = true;
                        local_tx_pd->flags =
                                MWIFIEX_TxPD_POWER_MGMT_LAST_PACKET;
                }
        }
}

/*
 * Create aggregated packet.
 *
 * This function creates an aggregated MSDU packet, by combining buffers
 * from the RA list. Each individual buffer is encapsulated as an AMSDU
 * subframe and all such subframes are concatenated together to form the
 * AMSDU packet.
 *
 * A TxPD is also added to the front of the resultant AMSDU packets for
 * transmission. The resultant packets format is -
 *
 * +---- ~ ----+------ ~ ------+------ ~ ------+-..-+------ ~ ------+
 * |    TxPD   |AMSDU sub-frame|AMSDU sub-frame| .. |AMSDU sub-frame|
 * |           |       1       |       2       | .. |       n       |
 * +---- ~ ----+------ ~ ------+------ ~ ------+ .. +------ ~ ------+
 */
int
mwifiex_11n_aggregate_pkt(struct mwifiex_private *priv,
                          struct mwifiex_ra_list_tbl *pra_list, int headroom,
                          int ptrindex, unsigned long ra_list_flags)
                          __releases(&priv->wmm.ra_list_spinlock)
{
        struct mwifiex_adapter *adapter = priv->adapter;
        struct sk_buff *skb_aggr, *skb_src;
        struct mwifiex_txinfo *tx_info_aggr, *tx_info_src;
        int pad = 0, ret;
        struct mwifiex_tx_param tx_param;
        struct txpd *ptx_pd = NULL;

        skb_src = skb_peek(&pra_list->skb_head);
        if (!skb_src) {
                spin_unlock_irqrestore(&priv->wmm.ra_list_spinlock,
                                       ra_list_flags);
                return 0;
        }

        tx_info_src = MWIFIEX_SKB_TXCB(skb_src);
        skb_aggr = dev_alloc_skb(adapter->tx_buf_size);
        if (!skb_aggr) {
                dev_err(adapter->dev, "%s: alloc skb_aggr\n", __func__);
                spin_unlock_irqrestore(&priv->wmm.ra_list_spinlock,
                                       ra_list_flags);
                return -1;
        }
        skb_reserve(skb_aggr, headroom + sizeof(struct txpd));
        tx_info_aggr =  MWIFIEX_SKB_TXCB(skb_aggr);

        tx_info_aggr->bss_type = tx_info_src->bss_type;
        tx_info_aggr->bss_num = tx_info_src->bss_num;
        skb_aggr->priority = skb_src->priority;

        do {
                /* Check if AMSDU can accommodate this MSDU */
                if (skb_tailroom(skb_aggr) < (skb_src->len + LLC_SNAP_LEN))
                        break;

                skb_src = skb_dequeue(&pra_list->skb_head);

                pra_list->total_pkts_size -= skb_src->len;

                atomic_dec(&priv->wmm.tx_pkts_queued);

                spin_unlock_irqrestore(&priv->wmm.ra_list_spinlock,
                                       ra_list_flags);
                mwifiex_11n_form_amsdu_pkt(skb_aggr, skb_src, &pad);

                mwifiex_write_data_complete(adapter, skb_src, 0, 0);

                spin_lock_irqsave(&priv->wmm.ra_list_spinlock, ra_list_flags);

                if (!mwifiex_is_ralist_valid(priv, pra_list, ptrindex)) {
                        spin_unlock_irqrestore(&priv->wmm.ra_list_spinlock,
                                               ra_list_flags);
                        return -1;
                }

                if (skb_tailroom(skb_aggr) < pad) {
                        pad = 0;
                        break;
                }
                skb_put(skb_aggr, pad);

                skb_src = skb_peek(&pra_list->skb_head);

        } while (skb_src);

        spin_unlock_irqrestore(&priv->wmm.ra_list_spinlock, ra_list_flags);

        /* Last AMSDU packet does not need padding */
        skb_trim(skb_aggr, skb_aggr->len - pad);

        /* Form AMSDU */
        mwifiex_11n_form_amsdu_txpd(priv, skb_aggr);
        if (GET_BSS_ROLE(priv) == MWIFIEX_BSS_ROLE_STA)
                ptx_pd = (struct txpd *)skb_aggr->data;

        skb_push(skb_aggr, headroom);

        if (adapter->iface_type == MWIFIEX_USB) {
                adapter->data_sent = true;
                ret = adapter->if_ops.host_to_card(adapter, MWIFIEX_USB_EP_DATA,
                                                   skb_aggr, NULL);
        } else {
                /*
                 * Padding per MSDU will affect the length of next
                 * packet and hence the exact length of next packet
                 * is uncertain here.
                 *
                 * Also, aggregation of transmission buffer, while
                 * downloading the data to the card, wont gain much
                 * on the AMSDU packets as the AMSDU packets utilizes
                 * the transmission buffer space to the maximum
                 * (adapter->tx_buf_size).
                 */
                tx_param.next_pkt_len = 0;

                ret = adapter->if_ops.host_to_card(adapter, MWIFIEX_TYPE_DATA,
                                                   skb_aggr, &tx_param);
        }
        switch (ret) {
        case -EBUSY:
                spin_lock_irqsave(&priv->wmm.ra_list_spinlock, ra_list_flags);
                if (!mwifiex_is_ralist_valid(priv, pra_list, ptrindex)) {
                        spin_unlock_irqrestore(&priv->wmm.ra_list_spinlock,
                                               ra_list_flags);
                        mwifiex_write_data_complete(adapter, skb_aggr, 1, -1);
                        return -1;
                }
                if (GET_BSS_ROLE(priv) == MWIFIEX_BSS_ROLE_STA &&
                    adapter->pps_uapsd_mode && adapter->tx_lock_flag) {
                                priv->adapter->tx_lock_flag = false;
                                if (ptx_pd)
                                        ptx_pd->flags = 0;
                }

                skb_queue_tail(&pra_list->skb_head, skb_aggr);

                pra_list->total_pkts_size += skb_aggr->len;

                atomic_inc(&priv->wmm.tx_pkts_queued);

                tx_info_aggr->flags |= MWIFIEX_BUF_FLAG_REQUEUED_PKT;
                spin_unlock_irqrestore(&priv->wmm.ra_list_spinlock,
                                       ra_list_flags);
                dev_dbg(adapter->dev, "data: -EBUSY is returned\n");
                break;
        case -1:
                if (adapter->iface_type != MWIFIEX_PCIE)
                        adapter->data_sent = false;
                dev_err(adapter->dev, "%s: host_to_card failed: %#x\n",
                        __func__, ret);
                adapter->dbg.num_tx_host_to_card_failure++;
                mwifiex_write_data_complete(adapter, skb_aggr, 1, ret);
                return 0;
        case -EINPROGRESS:
                if (adapter->iface_type != MWIFIEX_PCIE)
                        adapter->data_sent = false;
                break;
        case 0:
                mwifiex_write_data_complete(adapter, skb_aggr, 1, ret);
                break;
        default:
                break;
        }
        if (ret != -EBUSY) {
                mwifiex_rotate_priolists(priv, pra_list, ptrindex);
        }

        return 0;
}