mac80211: add U-APSD client support

Add Unscheduled Automatic Power-Save Delivery (U-APSD) client support. The
idea is that the data frames from the client trigger AP to send the buffered
frames with ACs which have U-APSD enabled. This decreases latency and makes it
possible to save even more power.

Driver needs to use IEEE80211_HW_UAPSD to enable the feature. The current
implementation assumes that firmware takes care of the wakeup and
hardware needing IEEE80211_HW_PS_NULLFUNC_STACK is not yet supported.

Tested with wl1251 on a Nokia N900 and Cisco Aironet 1231G AP and running
various test traffic with ping.

Signed-off-by: Kalle Valo <kalle.valo@nokia.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 10 insertions, 2 deletions

diff --git a/net/mac80211/work.c b/net/mac80211/work.c
index 7c5d95b1bc04..a74fd6ee0083 100644
--- a/net/mac80211/work.c
+++ b/net/mac80211/work.c
@@ -202,7 +202,7 @@ static void ieee80211_send_assoc(struct ieee80211_sub_if_data *sdata,
         struct ieee80211_local *local = sdata->local;
         struct sk_buff *skb;
         struct ieee80211_mgmt *mgmt;
-        u8 *pos;
+        u8 *pos, qos_info;
         const u8 *ies;
         size_t offset = 0, noffset;
         int i, len, count, rates_len, supp_rates_len;
@@ -375,6 +375,14 @@ static void ieee80211_send_assoc(struct ieee80211_sub_if_data *sdata,
         }
 
         if (wk->assoc.wmm_used && local->hw.queues >= 4) {
+                if (wk->assoc.uapsd_used) {
+                        qos_info = IEEE80211_DEFAULT_UAPSD_QUEUES;
+                        qos_info |= (IEEE80211_DEFAULT_MAX_SP_LEN <<
+                                     IEEE80211_WMM_IE_STA_QOSINFO_SP_SHIFT);
+                } else {
+                        qos_info = 0;
+                }
+
                 pos = skb_put(skb, 9);
                 *pos++ = WLAN_EID_VENDOR_SPECIFIC;
                 *pos++ = 7; /* len */
@@ -384,7 +392,7 @@ static void ieee80211_send_assoc(struct ieee80211_sub_if_data *sdata,
                 *pos++ = 2; /* WME */
                 *pos++ = 0; /* WME info */
                 *pos++ = 1; /* WME ver */
-                *pos++ = 0;
+                *pos++ = qos_info;
         }
 
         /* add any remaining custom (i.e. vendor specific here) IEs */