+void ieee80211_send_nullfunc(struct ieee80211_local *local,
+ struct ieee80211_sub_if_data *sdata,
+ int powersave)
+{
+ struct sk_buff *skb;
+ struct ieee80211_hdr *nullfunc;
+ __le16 fc;
+
+ if (WARN_ON(sdata->vif.type != NL80211_IFTYPE_STATION))
+ return;
+
+ skb = dev_alloc_skb(local->hw.extra_tx_headroom + 24);
+ if (!skb) {
+ printk(KERN_DEBUG "%s: failed to allocate buffer for nullfunc "
+ "frame\n", sdata->dev->name);
+ return;
+ }
+ skb_reserve(skb, local->hw.extra_tx_headroom);
+
+ nullfunc = (struct ieee80211_hdr *) skb_put(skb, 24);
+ memset(nullfunc, 0, 24);
+ fc = cpu_to_le16(IEEE80211_FTYPE_DATA | IEEE80211_STYPE_NULLFUNC |
+ IEEE80211_FCTL_TODS);
+ if (powersave)
+ fc |= cpu_to_le16(IEEE80211_FCTL_PM);
+ nullfunc->frame_control = fc;
+ memcpy(nullfunc->addr1, sdata->u.mgd.bssid, ETH_ALEN);
+ memcpy(nullfunc->addr2, sdata->dev->dev_addr, ETH_ALEN);
+ memcpy(nullfunc->addr3, sdata->u.mgd.bssid, ETH_ALEN);
+
+ ieee80211_tx_skb(sdata, skb, 0);
+}
+
+/* powersave */
+static void ieee80211_enable_ps(struct ieee80211_local *local,
+ struct ieee80211_sub_if_data *sdata)
+{
+ struct ieee80211_conf *conf = &local->hw.conf;
+
+ if (conf->dynamic_ps_timeout > 0 &&
+ !(local->hw.flags & IEEE80211_HW_SUPPORTS_DYNAMIC_PS)) {
+ mod_timer(&local->dynamic_ps_timer, jiffies +
+ msecs_to_jiffies(conf->dynamic_ps_timeout));
+ } else {
+ if (local->hw.flags & IEEE80211_HW_PS_NULLFUNC_STACK)
+ ieee80211_send_nullfunc(local, sdata, 1);
+ conf->flags |= IEEE80211_CONF_PS;
+ ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
+ }
+}
+
+static void ieee80211_change_ps(struct ieee80211_local *local)
+{
+ struct ieee80211_conf *conf = &local->hw.conf;
+
+ if (local->ps_sdata) {
+ if (!(local->ps_sdata->u.mgd.flags & IEEE80211_STA_ASSOCIATED))
+ return;
+
+ ieee80211_enable_ps(local, local->ps_sdata);
+ } else if (conf->flags & IEEE80211_CONF_PS) {
+ conf->flags &= ~IEEE80211_CONF_PS;
+ ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
+ del_timer_sync(&local->dynamic_ps_timer);
+ cancel_work_sync(&local->dynamic_ps_enable_work);
+ }
+}
+
+/* need to hold RTNL or interface lock */
+void ieee80211_recalc_ps(struct ieee80211_local *local)
+{
+ struct ieee80211_sub_if_data *sdata, *found = NULL;
+ int count = 0;
+
+ if (!(local->hw.flags & IEEE80211_HW_SUPPORTS_PS)) {
+ local->ps_sdata = NULL;
+ return;
+ }
+
+ list_for_each_entry(sdata, &local->interfaces, list) {
+ if (!netif_running(sdata->dev))
+ continue;
+ if (sdata->vif.type != NL80211_IFTYPE_STATION)
+ continue;
+ found = sdata;
+ count++;
+ }
+
+ if (count == 1 && found->u.mgd.powersave)
+ local->ps_sdata = found;
+ else
+ local->ps_sdata = NULL;
+
+ ieee80211_change_ps(local);
+}
+
+void ieee80211_dynamic_ps_disable_work(struct work_struct *work)
+{
+ struct ieee80211_local *local =
+ container_of(work, struct ieee80211_local,
+ dynamic_ps_disable_work);
+
+ if (local->hw.conf.flags & IEEE80211_CONF_PS) {
+ local->hw.conf.flags &= ~IEEE80211_CONF_PS;
+ ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
+ }
+
+ ieee80211_wake_queues_by_reason(&local->hw,
+ IEEE80211_QUEUE_STOP_REASON_PS);
+}
+
+void ieee80211_dynamic_ps_enable_work(struct work_struct *work)
+{
+ struct ieee80211_local *local =
+ container_of(work, struct ieee80211_local,
+ dynamic_ps_enable_work);
+ struct ieee80211_sub_if_data *sdata = local->ps_sdata;
+
+ /* can only happen when PS was just disabled anyway */
+ if (!sdata)
+ return;
+
+ if (local->hw.conf.flags & IEEE80211_CONF_PS)
+ return;
+
+ if (local->hw.flags & IEEE80211_HW_PS_NULLFUNC_STACK)
+ ieee80211_send_nullfunc(local, sdata, 1);
+
+ local->hw.conf.flags |= IEEE80211_CONF_PS;
+ ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
+}
+
+void ieee80211_dynamic_ps_timer(unsigned long data)
+{
+ struct ieee80211_local *local = (void *) data;
+
+ queue_work(local->hw.workqueue, &local->dynamic_ps_enable_work);
+}
+