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>

9 files changed, 106 insertions, 6 deletions

diff --git a/include/linux/ieee80211.h b/include/linux/ieee80211.h
index 602c0692c3fc..a8c6069a0d9f 100644
--- a/include/linux/ieee80211.h
+++ b/include/linux/ieee80211.h
@@ -120,6 +120,24 @@
 #define IEEE80211_QOS_CTL_TID_MASK      0x000F
 #define IEEE80211_QOS_CTL_TAG1D_MASK    0x0007
 
+/* U-APSD queue for WMM IEs sent by AP */
+#define IEEE80211_WMM_IE_AP_QOSINFO_UAPSD       (1<<7)
+
+/* U-APSD queues for WMM IEs sent by STA */
+#define IEEE80211_WMM_IE_STA_QOSINFO_AC_VO      (1<<0)
+#define IEEE80211_WMM_IE_STA_QOSINFO_AC_VI      (1<<1)
+#define IEEE80211_WMM_IE_STA_QOSINFO_AC_BK      (1<<2)
+#define IEEE80211_WMM_IE_STA_QOSINFO_AC_BE      (1<<3)
+#define IEEE80211_WMM_IE_STA_QOSINFO_AC_MASK    0x0f
+
+/* U-APSD max SP length for WMM IEs sent by STA */
+#define IEEE80211_WMM_IE_STA_QOSINFO_SP_ALL     0x00
+#define IEEE80211_WMM_IE_STA_QOSINFO_SP_2       0x01
+#define IEEE80211_WMM_IE_STA_QOSINFO_SP_4       0x02
+#define IEEE80211_WMM_IE_STA_QOSINFO_SP_6       0x03
+#define IEEE80211_WMM_IE_STA_QOSINFO_SP_MASK    0x03
+#define IEEE80211_WMM_IE_STA_QOSINFO_SP_SHIFT   5
+
 struct ieee80211_hdr {
         __le16 frame_control;
         __le16 duration_id;
diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index e1e73c6abeff..f313a3cbabda 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -113,6 +113,7 @@ struct ieee80211_tx_queue_params {
         u16 cw_min;
         u16 cw_max;
         u8 aifs;
+        bool uapsd;
 };
 
 /**
@@ -929,6 +930,11 @@ enum ieee80211_tkip_key_type {
  *      Hardware supports dynamic spatial multiplexing powersave,
  *      ie. can turn off all but one chain and then wake the rest
  *      up as required after, for example, rts/cts handshake.
+ *
+ * @IEEE80211_HW_SUPPORTS_UAPSD:
+ *      Hardware supports Unscheduled Automatic Power Save Delivery
+ *      (U-APSD) in managed mode. The mode is configured with
+ *      conf_tx() operation.
  */
 enum ieee80211_hw_flags {
         IEEE80211_HW_HAS_RATE_CONTROL                   = 1<<0,
@@ -948,6 +954,7 @@ enum ieee80211_hw_flags {
         IEEE80211_HW_BEACON_FILTER                      = 1<<14,
         IEEE80211_HW_SUPPORTS_STATIC_SMPS               = 1<<15,
         IEEE80211_HW_SUPPORTS_DYNAMIC_SMPS              = 1<<16,
+        IEEE80211_HW_SUPPORTS_UAPSD                     = 1<<17,
 };
 
 /**
diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index dc12e9466ffd..8286df5822d5 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1128,6 +1128,13 @@ static int ieee80211_set_txq_params(struct wiphy *wiphy,
         p.cw_max = params->cwmax;
         p.cw_min = params->cwmin;
         p.txop = params->txop;
+
+        /*
+         * Setting tx queue params disables u-apsd because it's only
+         * called in master mode.
+         */
+        p.uapsd = false;
+
         if (drv_conf_tx(local, params->queue, &p)) {
                 printk(KERN_DEBUG "%s: failed to set TX queue "
                        "parameters for queue %d\n",
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 3e4ac3f30857..3468e378509a 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -58,6 +58,15 @@ struct ieee80211_local;
 
 #define TU_TO_EXP_TIME(x)       (jiffies + usecs_to_jiffies((x) * 1024))
 
+#define IEEE80211_DEFAULT_UAPSD_QUEUES \
+        (IEEE80211_WMM_IE_STA_QOSINFO_AC_BK |   \
+         IEEE80211_WMM_IE_STA_QOSINFO_AC_BE |   \
+         IEEE80211_WMM_IE_STA_QOSINFO_AC_VI |   \
+         IEEE80211_WMM_IE_STA_QOSINFO_AC_VO)
+
+#define IEEE80211_DEFAULT_MAX_SP_LEN            \
+        IEEE80211_WMM_IE_STA_QOSINFO_SP_ALL
+
 struct ieee80211_fragment_entry {
         unsigned long first_frag_time;
         unsigned int seq;
@@ -78,6 +87,7 @@ struct ieee80211_bss {
         u8 dtim_period;
 
         bool wmm_used;
+        bool uapsd_supported;
 
         unsigned long last_probe_resp;
 
@@ -285,7 +295,7 @@ struct ieee80211_work {
                         u8 ssid[IEEE80211_MAX_SSID_LEN];
                         u8 ssid_len;
                         u8 supp_rates_len;
-                        bool wmm_used, use_11n;
+                        bool wmm_used, use_11n, uapsd_used;
                 } assoc;
                 struct {
                         u32 duration;
@@ -306,6 +316,7 @@ enum ieee80211_sta_flags {
         IEEE80211_STA_DISABLE_11N       = BIT(4),
         IEEE80211_STA_CSA_RECEIVED      = BIT(5),
         IEEE80211_STA_MFP_ENABLED       = BIT(6),
+        IEEE80211_STA_UAPSD_ENABLED     = BIT(7),
 };
 
 struct ieee80211_if_managed {
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index 468829143991..0054bba08ce1 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -491,6 +491,10 @@ int ieee80211_register_hw(struct ieee80211_hw *hw)
         else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC)
                 local->hw.wiphy->signal_type = CFG80211_SIGNAL_TYPE_UNSPEC;
 
+        WARN((local->hw.flags & IEEE80211_HW_SUPPORTS_UAPSD)
+             && (local->hw.flags & IEEE80211_HW_PS_NULLFUNC_STACK),
+             "U-APSD not supported with HW_PS_NULLFUNC_STACK\n");
+
         /*
          * Calculate scan IE length -- we need this to alloc
          * memory and to subtract from the driver limit. It
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 86f025bc9456..39c27d83a4f2 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -569,7 +569,7 @@ static void ieee80211_sta_wmm_params(struct ieee80211_local *local,
         struct ieee80211_tx_queue_params params;
         size_t left;
         int count;
-        u8 *pos;
+        u8 *pos, uapsd_queues = 0;
 
         if (local->hw.queues < 4)
                 return;
@@ -579,6 +579,10 @@ static void ieee80211_sta_wmm_params(struct ieee80211_local *local,
 
         if (wmm_param_len < 8 || wmm_param[5] /* version */ != 1)
                 return;
+
+        if (ifmgd->flags & IEEE80211_STA_UAPSD_ENABLED)
+                uapsd_queues = IEEE80211_DEFAULT_UAPSD_QUEUES;
+
         count = wmm_param[6] & 0x0f;
         if (count == ifmgd->wmm_last_param_set)
                 return;
@@ -593,6 +597,7 @@ static void ieee80211_sta_wmm_params(struct ieee80211_local *local,
         for (; left >= 4; left -= 4, pos += 4) {
                 int aci = (pos[0] >> 5) & 0x03;
                 int acm = (pos[0] >> 4) & 0x01;
+                bool uapsd = false;
                 int queue;
 
                 switch (aci) {
@@ -600,22 +605,30 @@ static void ieee80211_sta_wmm_params(struct ieee80211_local *local,
                         queue = 3;
                         if (acm)
                                 local->wmm_acm |= BIT(1) | BIT(2); /* BK/- */
+                        if (uapsd_queues & IEEE80211_WMM_IE_STA_QOSINFO_AC_BK)
+                                uapsd = true;
                         break;
                 case 2: /* AC_VI */
                         queue = 1;
                         if (acm)
                                 local->wmm_acm |= BIT(4) | BIT(5); /* CL/VI */
+                        if (uapsd_queues & IEEE80211_WMM_IE_STA_QOSINFO_AC_VI)
+                                uapsd = true;
                         break;
                 case 3: /* AC_VO */
                         queue = 0;
                         if (acm)
                                 local->wmm_acm |= BIT(6) | BIT(7); /* VO/NC */
+                        if (uapsd_queues & IEEE80211_WMM_IE_STA_QOSINFO_AC_VO)
+                                uapsd = true;
                         break;
                 case 0: /* AC_BE */
                 default:
                         queue = 2;
                         if (acm)
                                 local->wmm_acm |= BIT(0) | BIT(3); /* BE/EE */
+                        if (uapsd_queues & IEEE80211_WMM_IE_STA_QOSINFO_AC_BE)
+                                uapsd = true;
                         break;
                 }
 
@@ -623,11 +636,14 @@ static void ieee80211_sta_wmm_params(struct ieee80211_local *local,
                 params.cw_max = ecw2cw((pos[1] & 0xf0) >> 4);
                 params.cw_min = ecw2cw(pos[1] & 0x0f);
                 params.txop = get_unaligned_le16(pos + 2);
+                params.uapsd = uapsd;
+
 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
                 printk(KERN_DEBUG "%s: WMM queue=%d aci=%d acm=%d aifs=%d "
-                       "cWmin=%d cWmax=%d txop=%d\n",
+                       "cWmin=%d cWmax=%d txop=%d uapsd=%d\n",
                        wiphy_name(local->hw.wiphy), queue, aci, acm,
-                       params.aifs, params.cw_min, params.cw_max, params.txop);
+                       params.aifs, params.cw_min, params.cw_max, params.txop,
+                       params.uapsd);
 #endif
                 if (drv_conf_tx(local, queue, &params) && local->ops->conf_tx)
                         printk(KERN_DEBUG "%s: failed to set TX queue "
@@ -1906,6 +1922,15 @@ int ieee80211_mgd_assoc(struct ieee80211_sub_if_data *sdata,
         wk->assoc.ht_information_ie =
                 ieee80211_bss_get_ie(req->bss, WLAN_EID_HT_INFORMATION);
 
+        if (bss->wmm_used && bss->uapsd_supported &&
+            (sdata->local->hw.flags & IEEE80211_HW_SUPPORTS_UAPSD)) {
+                wk->assoc.uapsd_used = true;
+                ifmgd->flags |= IEEE80211_STA_UAPSD_ENABLED;
+        } else {
+                wk->assoc.uapsd_used = false;
+                ifmgd->flags &= ~IEEE80211_STA_UAPSD_ENABLED;
+        }
+
         ssid = ieee80211_bss_get_ie(req->bss, WLAN_EID_SSID);
         memcpy(wk->assoc.ssid, ssid + 2, ssid[1]);
         wk->assoc.ssid_len = ssid[1];
diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c
index 30cb62bb45b3..9afe2f9885dc 100644
--- a/net/mac80211/scan.c
+++ b/net/mac80211/scan.c
@@ -54,6 +54,23 @@ void ieee80211_rx_bss_put(struct ieee80211_local *local,
         cfg80211_put_bss(container_of((void *)bss, struct cfg80211_bss, priv));
 }
 
+static bool is_uapsd_supported(struct ieee802_11_elems *elems)
+{
+        u8 qos_info;
+
+        if (elems->wmm_info && elems->wmm_info_len == 7
+            && elems->wmm_info[5] == 1)
+                qos_info = elems->wmm_info[6];
+        else if (elems->wmm_param && elems->wmm_param_len == 24
+                 && elems->wmm_param[5] == 1)
+                qos_info = elems->wmm_param[6];
+        else
+                /* no valid wmm information or parameter element found */
+                return false;
+
+        return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
+}
+
 struct ieee80211_bss *
 ieee80211_bss_info_update(struct ieee80211_local *local,
                           struct ieee80211_rx_status *rx_status,
@@ -117,6 +134,7 @@ ieee80211_bss_info_update(struct ieee80211_local *local,
         }
 
         bss->wmm_used = elems->wmm_param || elems->wmm_info;
+        bss->uapsd_supported = is_uapsd_supported(elems);
 
         if (!beacon)
                 bss->last_probe_resp = jiffies;
diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index a2ba6e29bd9a..e278f97c8305 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -792,6 +792,8 @@ void ieee80211_set_wmm_default(struct ieee80211_sub_if_data *sdata)
                         break;
                 }
 
+                qparam.uapsd = false;
+
                 drv_conf_tx(local, queue, &qparam);
         }
 }
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 */