/*
 * This file is part of wl1251
 *
 * Copyright (c) 1998-2007 Texas Instruments Incorporated
 * Copyright (C) 2008 Nokia Corporation
 *
 * Contact: Kalle Valo <kalle.valo@nokia.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>

#include "wl1251.h"
#include "wl1251_reg.h"
#include "wl1251_tx.h"
#include "wl1251_ps.h"
#include "wl1251_io.h"

static bool wl1251_tx_double_buffer_busy(struct wl1251 *wl, u32 data_out_count)
{
        int used, data_in_count;

        data_in_count = wl->data_in_count;

        if (data_in_count < data_out_count)
                /* data_in_count has wrapped */
                data_in_count += TX_STATUS_DATA_OUT_COUNT_MASK + 1;

        used = data_in_count - data_out_count;

        WARN_ON(used < 0);
        WARN_ON(used > DP_TX_PACKET_RING_CHUNK_NUM);

        if (used >= DP_TX_PACKET_RING_CHUNK_NUM)
                return true;
        else
                return false;
}

static int wl1251_tx_path_status(struct wl1251 *wl)
{
        u32 status, addr, data_out_count;
        bool busy;

        addr = wl->data_path->tx_control_addr;
        status = wl1251_mem_read32(wl, addr);
        data_out_count = status & TX_STATUS_DATA_OUT_COUNT_MASK;
        busy = wl1251_tx_double_buffer_busy(wl, data_out_count);

        if (busy)
                return -EBUSY;

        return 0;
}

static int wl1251_tx_id(struct wl1251 *wl, struct sk_buff *skb)
{
        int i;

        for (i = 0; i < FW_TX_CMPLT_BLOCK_SIZE; i++)
                if (wl->tx_frames[i] == NULL) {
                        wl->tx_frames[i] = skb;
                        return i;
                }

        return -EBUSY;
}

static void wl1251_tx_control(struct tx_double_buffer_desc *tx_hdr,
                              struct ieee80211_tx_info *control, u16 fc)
{
        *(u16 *)&tx_hdr->control = 0;

        tx_hdr->control.rate_policy = 0;

        /* 802.11 packets */
        tx_hdr->control.packet_type = 0;

        if (control->flags & IEEE80211_TX_CTL_NO_ACK)
                tx_hdr->control.ack_policy = 1;

        tx_hdr->control.tx_complete = 1;

        if ((fc & IEEE80211_FTYPE_DATA) &&
            ((fc & IEEE80211_STYPE_QOS_DATA) ||
             (fc & IEEE80211_STYPE_QOS_NULLFUNC)))
                tx_hdr->control.qos = 1;
}

/* RSN + MIC = 8 + 8 = 16 bytes (worst case - AES). */
#define MAX_MSDU_SECURITY_LENGTH      16
#define MAX_MPDU_SECURITY_LENGTH      16
#define WLAN_QOS_HDR_LEN              26
#define MAX_MPDU_HEADER_AND_SECURITY  (MAX_MPDU_SECURITY_LENGTH + \
                                       WLAN_QOS_HDR_LEN)
#define HW_BLOCK_SIZE                 252
static void wl1251_tx_frag_block_num(struct tx_double_buffer_desc *tx_hdr)
{
        u16 payload_len, frag_threshold, mem_blocks;
        u16 num_mpdus, mem_blocks_per_frag;

        frag_threshold = IEEE80211_MAX_FRAG_THRESHOLD;
        tx_hdr->frag_threshold = cpu_to_le16(frag_threshold);

        payload_len = tx_hdr->length + MAX_MSDU_SECURITY_LENGTH;

        if (payload_len > frag_threshold) {
                mem_blocks_per_frag =
                        ((frag_threshold + MAX_MPDU_HEADER_AND_SECURITY) /
                         HW_BLOCK_SIZE) + 1;
                num_mpdus = payload_len / frag_threshold;
                mem_blocks = num_mpdus * mem_blocks_per_frag;
                payload_len -= num_mpdus * frag_threshold;
                num_mpdus++;

        } else {
                mem_blocks_per_frag = 0;
                mem_blocks = 0;
                num_mpdus = 1;
        }

        mem_blocks += (payload_len / HW_BLOCK_SIZE) + 1;

        if (num_mpdus > 1)
                mem_blocks += min(num_mpdus, mem_blocks_per_frag);

        tx_hdr->num_mem_blocks = mem_blocks;
}

static int wl1251_tx_fill_hdr(struct wl1251 *wl, struct sk_buff *skb,
                              struct ieee80211_tx_info *control)
{
        struct tx_double_buffer_desc *tx_hdr;
        struct ieee80211_rate *rate;
        int id;
        u16 fc;

        if (!skb)
                return -EINVAL;

        id = wl1251_tx_id(wl, skb);
        if (id < 0)
                return id;

        fc = *(u16 *)skb->data;
        tx_hdr = (struct tx_double_buffer_desc *) skb_push(skb,
                                                           sizeof(*tx_hdr));

        tx_hdr->length = cpu_to_le16(skb->len - sizeof(*tx_hdr));
        rate = ieee80211_get_tx_rate(wl->hw, control);
        tx_hdr->rate = cpu_to_le16(rate->hw_value);
        tx_hdr->expiry_time = cpu_to_le32(1 << 16);
        tx_hdr->id = id;

        /* FIXME: how to get the correct queue id? */
        tx_hdr->xmit_queue = 0;

        wl1251_tx_control(tx_hdr, control, fc);
        wl1251_tx_frag_block_num(tx_hdr);

        return 0;
}

/* We copy the packet to the target */
static int wl1251_tx_send_packet(struct wl1251 *wl, struct sk_buff *skb,
                                 struct ieee80211_tx_info *control)
{
        struct tx_double_buffer_desc *tx_hdr;
        int len;
        u32 addr;

        if (!skb)
                return -EINVAL;

        tx_hdr = (struct tx_double_buffer_desc *) skb->data;

        if (control->control.hw_key &&
            control->control.hw_key->alg == ALG_TKIP) {
                int hdrlen;
                u16 fc;
                u8 *pos;

                fc = *(u16 *)(skb->data + sizeof(*tx_hdr));
                tx_hdr->length += WL1251_TKIP_IV_SPACE;

                hdrlen = ieee80211_hdrlen(fc);

                pos = skb_push(skb, WL1251_TKIP_IV_SPACE);
                memmove(pos, pos + WL1251_TKIP_IV_SPACE,
                        sizeof(*tx_hdr) + hdrlen);
        }

        /* Revisit. This is a workaround for getting non-aligned packets.
           This happens at least with EAPOL packets from the user space.
           Our DMA requires packets to be aligned on a 4-byte boundary.
        */
        if (unlikely((long)skb->data & 0x03)) {
                int offset = (4 - (long)skb->data) & 0x03;
                wl1251_debug(DEBUG_TX, "skb offset %d", offset);

                /* check whether the current skb can be used */
                if (!skb_cloned(skb) && (skb_tailroom(skb) >= offset)) {
                        unsigned char *src = skb->data;

                        /* align the buffer on a 4-byte boundary */
                        skb_reserve(skb, offset);
                        memmove(skb->data, src, skb->len);
                } else {
                        wl1251_info("No handler, fixme!");
                        return -EINVAL;
                }
        }

        /* Our skb->data at this point includes the HW header */
        len = WL1251_TX_ALIGN(skb->len);

        if (wl->data_in_count & 0x1)
                addr = wl->data_path->tx_packet_ring_addr +
                        wl->data_path->tx_packet_ring_chunk_size;
        else
                addr = wl->data_path->tx_packet_ring_addr;

        wl1251_mem_write(wl, addr, skb->data, len);

        wl1251_debug(DEBUG_TX, "tx id %u skb 0x%p payload %u rate 0x%x",
                     tx_hdr->id, skb, tx_hdr->length, tx_hdr->rate);

        return 0;
}

static void wl1251_tx_trigger(struct wl1251 *wl)
{
        u32 data, addr;

        if (wl->data_in_count & 0x1) {
                addr = ACX_REG_INTERRUPT_TRIG_H;
                data = INTR_TRIG_TX_PROC1;
        } else {
                addr = ACX_REG_INTERRUPT_TRIG;
                data = INTR_TRIG_TX_PROC0;
        }

        wl1251_reg_write32(wl, addr, data);

        /* Bumping data in */
        wl->data_in_count = (wl->data_in_count + 1) &
                TX_STATUS_DATA_OUT_COUNT_MASK;
}

/* caller must hold wl->mutex */
static int wl1251_tx_frame(struct wl1251 *wl, struct sk_buff *skb)
{
        struct ieee80211_tx_info *info;
        int ret = 0;
        u8 idx;

        info = IEEE80211_SKB_CB(skb);

        if (info->control.hw_key) {
                idx = info->control.hw_key->hw_key_idx;
                if (unlikely(wl->default_key != idx)) {
                        ret = wl1251_acx_default_key(wl, idx);
                        if (ret < 0)
                                return ret;
                }
        }

        ret = wl1251_tx_path_status(wl);
        if (ret < 0)
                return ret;

        ret = wl1251_tx_fill_hdr(wl, skb, info);
        if (ret < 0)
                return ret;

        ret = wl1251_tx_send_packet(wl, skb, info);
        if (ret < 0)
                return ret;

        wl1251_tx_trigger(wl);

        return ret;
}

void wl1251_tx_work(struct work_struct *work)
{
        struct wl1251 *wl = container_of(work, struct wl1251, tx_work);
        struct sk_buff *skb;
        bool woken_up = false;
        int ret;

        mutex_lock(&wl->mutex);

        if (unlikely(wl->state == WL1251_STATE_OFF))
                goto out;

        while ((skb = skb_dequeue(&wl->tx_queue))) {
                if (!woken_up) {
                        ret = wl1251_ps_elp_wakeup(wl);
                        if (ret < 0)
                                goto out;
                        woken_up = true;
                }

                ret = wl1251_tx_frame(wl, skb);
                if (ret == -EBUSY) {
                        /* firmware buffer is full, stop queues */
                        wl1251_debug(DEBUG_TX, "tx_work: fw buffer full, "
                                     "stop queues");
                        ieee80211_stop_queues(wl->hw);
                        wl->tx_queue_stopped = true;
                        skb_queue_head(&wl->tx_queue, skb);
                        goto out;
                } else if (ret < 0) {
                        dev_kfree_skb(skb);
                        goto out;
                }
        }

out:
        if (woken_up)
                wl1251_ps_elp_sleep(wl);

        mutex_unlock(&wl->mutex);
}

static const char *wl1251_tx_parse_status(u8 status)
{
        /* 8 bit status field, one character per bit plus null */
        static char buf[9];
        int i = 0;

        memset(buf, 0, sizeof(buf));

        if (status & TX_DMA_ERROR)
                buf[i++] = 'm';
        if (status & TX_DISABLED)
                buf[i++] = 'd';
        if (status & TX_RETRY_EXCEEDED)
                buf[i++] = 'r';
        if (status & TX_TIMEOUT)
                buf[i++] = 't';
        if (status & TX_KEY_NOT_FOUND)
                buf[i++] = 'k';
        if (status & TX_ENCRYPT_FAIL)
                buf[i++] = 'e';
        if (status & TX_UNAVAILABLE_PRIORITY)
                buf[i++] = 'p';

        /* bit 0 is unused apparently */

        return buf;
}

static void wl1251_tx_packet_cb(struct wl1251 *wl,
                                struct tx_result *result)
{
        struct ieee80211_tx_info *info;
        struct sk_buff *skb;
        int hdrlen, ret;
        u8 *frame;

        skb = wl->tx_frames[result->id];
        if (skb == NULL) {
                wl1251_error("SKB for packet %d is NULL", result->id);
                return;
        }

        info = IEEE80211_SKB_CB(skb);

        if (!(info->flags & IEEE80211_TX_CTL_NO_ACK) &&
            (result->status == TX_SUCCESS))
                info->flags |= IEEE80211_TX_STAT_ACK;

        info->status.rates[0].count = result->ack_failures + 1;
        wl->stats.retry_count += result->ack_failures;

        /*
         * We have to remove our private TX header before pushing
         * the skb back to mac80211.
         */
        frame = skb_pull(skb, sizeof(struct tx_double_buffer_desc));
        if (info->control.hw_key &&
            info->control.hw_key->alg == ALG_TKIP) {
                hdrlen = ieee80211_get_hdrlen_from_skb(skb);
                memmove(frame + WL1251_TKIP_IV_SPACE, frame, hdrlen);
                skb_pull(skb, WL1251_TKIP_IV_SPACE);
        }

        wl1251_debug(DEBUG_TX, "tx status id %u skb 0x%p failures %u rate 0x%x"
                     " status 0x%x (%s)",
                     result->id, skb, result->ack_failures, result->rate,
                     result->status, wl1251_tx_parse_status(result->status));


        ieee80211_tx_status(wl->hw, skb);

        wl->tx_frames[result->id] = NULL;

        if (wl->tx_queue_stopped) {
                wl1251_debug(DEBUG_TX, "cb: queue was stopped");

                skb = skb_dequeue(&wl->tx_queue);

                /* The skb can be NULL because tx_work might have been
                   scheduled before the queue was stopped making the
                   queue empty */

                if (skb) {
                        ret = wl1251_tx_frame(wl, skb);
                        if (ret == -EBUSY) {
                                /* firmware buffer is still full */
                                wl1251_debug(DEBUG_TX, "cb: fw buffer "
                                             "still full");
                                skb_queue_head(&wl->tx_queue, skb);
                                return;
                        } else if (ret < 0) {
                                dev_kfree_skb(skb);
                                return;
                        }
                }

                wl1251_debug(DEBUG_TX, "cb: waking queues");
                ieee80211_wake_queues(wl->hw);
                wl->tx_queue_stopped = false;
        }
}

/* Called upon reception of a TX complete interrupt */
void wl1251_tx_complete(struct wl1251 *wl)
{
        int i, result_index, num_complete = 0;
        struct tx_result result[FW_TX_CMPLT_BLOCK_SIZE], *result_ptr;

        if (unlikely(wl->state != WL1251_STATE_ON))
                return;

        /* First we read the result */
        wl1251_mem_read(wl, wl->data_path->tx_complete_addr,
                            result, sizeof(result));

        result_index = wl->next_tx_complete;

        for (i = 0; i < ARRAY_SIZE(result); i++) {
                result_ptr = &result[result_index];

                if (result_ptr->done_1 == 1 &&
                    result_ptr->done_2 == 1) {
                        wl1251_tx_packet_cb(wl, result_ptr);

                        result_ptr->done_1 = 0;
                        result_ptr->done_2 = 0;

                        result_index = (result_index + 1) &
                                (FW_TX_CMPLT_BLOCK_SIZE - 1);
                        num_complete++;
                } else {
                        break;
                }
        }

        /* Every completed frame needs to be acknowledged */
        if (num_complete) {
                /*
                 * If we've wrapped, we have to clear
                 * the results in 2 steps.
                 */
                if (result_index > wl->next_tx_complete) {
                        /* Only 1 write is needed */
                        wl1251_mem_write(wl,
                                         wl->data_path->tx_complete_addr +
                                         (wl->next_tx_complete *
                                          sizeof(struct tx_result)),
                                         &result[wl->next_tx_complete],
                                         num_complete *
                                         sizeof(struct tx_result));


                } else if (result_index < wl->next_tx_complete) {
                        /* 2 writes are needed */
                        wl1251_mem_write(wl,
                                         wl->data_path->tx_complete_addr +
                                         (wl->next_tx_complete *
                                          sizeof(struct tx_result)),
                                         &result[wl->next_tx_complete],
                                         (FW_TX_CMPLT_BLOCK_SIZE -
                                          wl->next_tx_complete) *
                                         sizeof(struct tx_result));

                        wl1251_mem_write(wl,
                                         wl->data_path->tx_complete_addr,
                                         result,
                                         (num_complete -
                                          FW_TX_CMPLT_BLOCK_SIZE +
                                          wl->next_tx_complete) *
                                         sizeof(struct tx_result));

                } else {
                        /* We have to write the whole array */
                        wl1251_mem_write(wl,
                                         wl->data_path->tx_complete_addr,
                                         result,
                                         FW_TX_CMPLT_BLOCK_SIZE *
                                         sizeof(struct tx_result));
                }

        }

        wl->next_tx_complete = result_index;
}

/* caller must hold wl->mutex */
void wl1251_tx_flush(struct wl1251 *wl)
{
        int i;
        struct sk_buff *skb;
        struct ieee80211_tx_info *info;

        /* TX failure */
/*      control->flags = 0; FIXME */

        while ((skb = skb_dequeue(&wl->tx_queue))) {
                info = IEEE80211_SKB_CB(skb);

                wl1251_debug(DEBUG_TX, "flushing skb 0x%p", skb);

                if (!(info->flags & IEEE80211_TX_CTL_REQ_TX_STATUS))
                                continue;

                ieee80211_tx_status(wl->hw, skb);
        }

        for (i = 0; i < FW_TX_CMPLT_BLOCK_SIZE; i++)
                if (wl->tx_frames[i] != NULL) {
                        skb = wl->tx_frames[i];
                        info = IEEE80211_SKB_CB(skb);

                        if (!(info->flags & IEEE80211_TX_CTL_REQ_TX_STATUS))
                                continue;

                        ieee80211_tx_status(wl->hw, skb);
                        wl->tx_frames[i] = NULL;
                }
}