传输途径 ath9k层到硬件层

这里只写了ath9k层到虚拟硬件层的一些东西，mac层的没有整理。

 传输途径主要从ath9k_tx() --->ath_tx_start() --->ath_tx_send_normal() --->ath_tx_txqaddbuf()---->ath9k_hw_txstart()

ath9k_tx（）（main.c）：

static void ath9k_tx(struct ieee80211_hw *hw,

                   struct ieee80211_tx_control *control,

                   struct sk_buff *skb)

{

       struct ath_softc *sc = hw->priv;

       struct ath_common *common = ath9k_hw_common(sc->sc_ah);

       struct ath_tx_control txctl;

       struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;

       unsigned long flags;

 

       if (sc->ps_enabled) {

              /*

               * mac80211 does not set PM field for normal data frames, so we

               * need to update that based on the current PS mode.

               */

              //加载结构ath_sofc中硬件的详细信息和更新PM位

              if (ieee80211_is_data(hdr->frame_control) &&

                  !ieee80211_is_nullfunc(hdr->frame_control) &&

                  !ieee80211_has_pm(hdr->frame_control)) {

                     ath_dbg(common, PS,

                            "Add PM=1 for a TX frame while in PS mode\n");

                     hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PM);

              }

       }

 

       if (unlikely(sc->sc_ah->power_mode == ATH9K_PM_NETWORK_SLEEP)) {

              /*

               * We are using PS-Poll and mac80211 can request TX while in

               * power save mode. Need to wake up hardware for the TX to be

               * completed and if needed, also for RX of buffered frames.

               */

              ath9k_ps_wakeup(sc); //唤醒正在休眠的硬件

              spin_lock_irqsave(&sc->sc_pm_lock, flags);

              if (!(sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_AUTOSLEEP))

                     ath9k_hw_setrxabort(sc->sc_ah, 0);

              if (ieee80211_is_pspoll(hdr->frame_control)) {

                     ath_dbg(common, PS,

                            "Sending PS-Poll to pick a buffered frame\n");

                     sc->ps_flags |= PS_WAIT_FOR_PSPOLL_DATA;

              } else {

                     ath_dbg(common, PS, "Wake up to complete TX\n");

                     sc->ps_flags |= PS_WAIT_FOR_TX_ACK;

              }

              /*

               * The actual restore operation will happen only after

               * the ps_flags bit is cleared. We are just dropping

               * the ps_usecount here.

               */

              spin_unlock_irqrestore(&sc->sc_pm_lock, flags);

              ath9k_ps_restore(sc);

       }

 

       /*

        * Cannot tx while the hardware is in full sleep, it first needs a full

        * chip reset to recover from that

        */

       if (unlikely(sc->sc_ah->power_mode == ATH9K_PM_FULL_SLEEP)) {

              ath_err(common, "TX while HW is in FULL_SLEEP mode\n");

              goto exit;

       }

       //用数据结构ath_tx_control跟踪传输状态

       memset(&txctl, 0, sizeof(struct ath_tx_control));

       txctl.txq = sc->tx.txq_map[skb_get_queue_mapping(skb)];

       txctl.sta = control->sta;

 

       ath_dbg(common, XMIT, "transmitting packet, skb: %p\n", skb);

       //这里进入下一步的传输，在ath_tx_start中启动传输

       if (ath_tx_start(hw, skb, &txctl) != 0) {

              ath_dbg(common, XMIT, "TX failed\n");

              TX_STAT_INC(txctl.txq->axq_qnum, txfailed);

              goto exit;

       }

 

       return;

exit:

       ieee80211_free_txskb(hw, skb);

}