tx.c

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/*
 * This file contains the handling of TX in wlan driver.
 */
#include <linux/hardirq.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/sched.h>
#include <linux/export.h>
#include <net/cfg80211.h>

#include "host.h"
#include "radiotap.h"
#include "decl.h"
#include "defs.h"
#include "dev.h"
#include "mesh.h"

static u32 convert_radiotap_rate_to_mv(u8 rate)
{
    switch (rate) {
    case 2:     /*   1 Mbps */
        return 0 | (1 << 4);
    case 4:     /*   2 Mbps */
        return 1 | (1 << 4);
    case 11:        /* 5.5 Mbps */
        return 2 | (1 << 4);
    case 22:        /*  11 Mbps */
        return 3 | (1 << 4);
    case 12:        /*   6 Mbps */
        return 4 | (1 << 4);
    case 18:        /*   9 Mbps */
        return 5 | (1 << 4);
    case 24:        /*  12 Mbps */
        return 6 | (1 << 4);
    case 36:        /*  18 Mbps */
        return 7 | (1 << 4);
    case 48:        /*  24 Mbps */
        return 8 | (1 << 4);
    case 72:        /*  36 Mbps */
        return 9 | (1 << 4);
    case 96:        /*  48 Mbps */
        return 10 | (1 << 4);
    case 108:       /*  54 Mbps */
        return 11 | (1 << 4);
    }
    return 0;
}

netdev_tx_t lbs_hard_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
    unsigned long flags;
    struct lbs_private *priv = dev->ml_priv;
    struct txpd *txpd;
    char *p802x_hdr;
    uint16_t pkt_len;
    netdev_tx_t ret = NETDEV_TX_OK;

    lbs_deb_enter(LBS_DEB_TX);

    /* We need to protect against the queues being restarted before
       we get round to stopping them */
    spin_lock_irqsave(&priv->driver_lock, flags);

    if (priv->surpriseremoved)
        goto free;

    if (!skb->len || (skb->len > MRVDRV_ETH_TX_PACKET_BUFFER_SIZE)) {
        lbs_deb_tx("tx err: skb length %d 0 or > %zd\n",
               skb->len, MRVDRV_ETH_TX_PACKET_BUFFER_SIZE);
        /* We'll never manage to send this one; drop it and return 'OK' */

        dev->stats.tx_dropped++;
        dev->stats.tx_errors++;
        goto free;
    }


    netif_stop_queue(priv->dev);
    if (priv->mesh_dev)
        netif_stop_queue(priv->mesh_dev);

    if (priv->tx_pending_len) {
        /* This can happen if packets come in on the mesh and eth
           device simultaneously -- there's no mutual exclusion on
           hard_start_xmit() calls between devices. */
        lbs_deb_tx("Packet on %s while busy\n", dev->name);
        ret = NETDEV_TX_BUSY;
        goto unlock;
    }

    priv->tx_pending_len = -1;
    spin_unlock_irqrestore(&priv->driver_lock, flags);

    lbs_deb_hex(LBS_DEB_TX, "TX Data", skb->data, min_t(unsigned int, skb->len, 100));

    txpd = (void *)priv->tx_pending_buf;
    memset(txpd, 0, sizeof(struct txpd));

    p802x_hdr = skb->data;
    pkt_len = skb->len;

    if (priv->wdev->iftype == NL80211_IFTYPE_MONITOR) {
        struct tx_radiotap_hdr *rtap_hdr = (void *)skb->data;

        /* set txpd fields from the radiotap header */
        txpd->tx_control = cpu_to_le32(convert_radiotap_rate_to_mv(rtap_hdr->rate));

        /* skip the radiotap header */
        p802x_hdr += sizeof(*rtap_hdr);
        pkt_len -= sizeof(*rtap_hdr);

        /* copy destination address from 802.11 header */
        memcpy(txpd->tx_dest_addr_high, p802x_hdr + 4, ETH_ALEN);
    } else {
        /* copy destination address from 802.3 header */
        memcpy(txpd->tx_dest_addr_high, p802x_hdr, ETH_ALEN);
    }

    txpd->tx_packet_length = cpu_to_le16(pkt_len);
    txpd->tx_packet_location = cpu_to_le32(sizeof(struct txpd));

    lbs_mesh_set_txpd(priv, dev, txpd);

    lbs_deb_hex(LBS_DEB_TX, "txpd", (u8 *) &txpd, sizeof(struct txpd));

    lbs_deb_hex(LBS_DEB_TX, "Tx Data", (u8 *) p802x_hdr, le16_to_cpu(txpd->tx_packet_length));

    memcpy(&txpd[1], p802x_hdr, le16_to_cpu(txpd->tx_packet_length));

    spin_lock_irqsave(&priv->driver_lock, flags);
    priv->tx_pending_len = pkt_len + sizeof(struct txpd);

    lbs_deb_tx("%s lined up packet\n", __func__);

    dev->stats.tx_packets++;
    dev->stats.tx_bytes += skb->len;

    if (priv->wdev->iftype == NL80211_IFTYPE_MONITOR) {
        /* Keep the skb to echo it back once Tx feedback is
           received from FW */
        skb_orphan(skb);

        /* Keep the skb around for when we get feedback */
        priv->currenttxskb = skb;
    } else {
 free:
        dev_kfree_skb_any(skb);
    }

 unlock:
    spin_unlock_irqrestore(&priv->driver_lock, flags);
    wake_up(&priv->waitq);

    lbs_deb_leave_args(LBS_DEB_TX, "ret %d", ret);
    return ret;
}

void lbs_send_tx_feedback(struct lbs_private *priv, u32 try_count)
{
    struct tx_radiotap_hdr *radiotap_hdr;

    if (priv->wdev->iftype != NL80211_IFTYPE_MONITOR ||
        priv->currenttxskb == NULL)
        return;

    radiotap_hdr = (struct tx_radiotap_hdr *)priv->currenttxskb->data;

    radiotap_hdr->data_retries = try_count ?
        (1 + priv->txretrycount - try_count) : 0;

    priv->currenttxskb->protocol = eth_type_trans(priv->currenttxskb,
                              priv->dev);
    netif_rx(priv->currenttxskb);

    priv->currenttxskb = NULL;

    if (priv->connect_status == LBS_CONNECTED)
        netif_wake_queue(priv->dev);

    if (priv->mesh_dev && netif_running(priv->mesh_dev))
        netif_wake_queue(priv->mesh_dev);
}
EXPORT_SYMBOL_GPL(lbs_send_tx_feedback);