mac80211: enable spatial multiplexing powersave

Enable spatial multiplexing in mac80211 by telling the
driver what to do and, where necessary, sending action
frames to the AP to update the requested SMPS mode.

Also includes a trivial implementation for hwsim that
just logs the requested mode.

For now, the userspace interface is in debugfs only,
and let you toggle the requested mode at any time.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/mac80211_hwsim.c

@@ -618,12 +618,26 @@ static int mac80211_hwsim_config(struct ieee80211_hw *hw, u32 changed)
 {
 	struct mac80211_hwsim_data *data = hw->priv;
 	struct ieee80211_conf *conf = &hw->conf;
-
-	printk(KERN_DEBUG "%s:%s (freq=%d idle=%d ps=%d)\n",
+	static const char *chantypes[4] = {
+		[NL80211_CHAN_NO_HT] = "noht",
+		[NL80211_CHAN_HT20] = "ht20",
+		[NL80211_CHAN_HT40MINUS] = "ht40-",
+		[NL80211_CHAN_HT40PLUS] = "ht40+",
+	};
+	static const char *smps_modes[IEEE80211_SMPS_NUM_MODES] = {
+		[IEEE80211_SMPS_AUTOMATIC] = "auto",
+		[IEEE80211_SMPS_OFF] = "off",
+		[IEEE80211_SMPS_STATIC] = "static",
+		[IEEE80211_SMPS_DYNAMIC] = "dynamic",
+	};
+
+	printk(KERN_DEBUG "%s:%s (freq=%d/%s idle=%d ps=%d smps=%s)\n",
 	       wiphy_name(hw->wiphy), __func__,
 	       conf->channel->center_freq,
+	       chantypes[conf->channel_type],
 	       !!(conf->flags & IEEE80211_CONF_IDLE),
-	       !!(conf->flags & IEEE80211_CONF_PS));
+	       !!(conf->flags & IEEE80211_CONF_PS),
+	       smps_modes[conf->smps_mode]);
 
 	data->idle = !!(conf->flags & IEEE80211_CONF_IDLE);
 
@@ -1082,7 +1096,9 @@ static int __init init_mac80211_hwsim(void)
 			BIT(NL80211_IFTYPE_MESH_POINT);
 
 		hw->flags = IEEE80211_HW_MFP_CAPABLE |
-			    IEEE80211_HW_SIGNAL_DBM;
+			    IEEE80211_HW_SIGNAL_DBM |
+			    IEEE80211_HW_SUPPORTS_STATIC_SMPS |
+			    IEEE80211_HW_SUPPORTS_DYNAMIC_SMPS;
 
 		/* ask mac80211 to reserve space for magic */
 		hw->vif_data_size = sizeof(struct hwsim_vif_priv);

include/linux/ieee80211.h

@@ -707,6 +707,10 @@ struct ieee80211_mgmt {
 					u8 action;
 					u8 trans_id[WLAN_SA_QUERY_TR_ID_LEN];
 				} __attribute__ ((packed)) sa_query;
+				struct {
+					u8 action;
+					u8 smps_control;
+				} __attribute__ ((packed)) ht_smps;
 			} u;
 		} __attribute__ ((packed)) action;
 	} u;
@@ -824,6 +828,7 @@ struct ieee80211_ht_cap {
 #define IEEE80211_HT_CAP_LDPC_CODING		0x0001
 #define IEEE80211_HT_CAP_SUP_WIDTH_20_40	0x0002
 #define IEEE80211_HT_CAP_SM_PS			0x000C
+#define		IEEE80211_HT_CAP_SM_PS_SHIFT	2
 #define IEEE80211_HT_CAP_GRN_FLD		0x0010
 #define IEEE80211_HT_CAP_SGI_20			0x0020
 #define IEEE80211_HT_CAP_SGI_40			0x0040
@@ -839,6 +844,7 @@ struct ieee80211_ht_cap {
 /* 802.11n HT capability AMPDU settings (for ampdu_params_info) */
 #define IEEE80211_HT_AMPDU_PARM_FACTOR		0x03
 #define IEEE80211_HT_AMPDU_PARM_DENSITY		0x1C
+#define		IEEE80211_HT_AMPDU_PARM_DENSITY_SHIFT	2
 
 /*
  * Maximum length of AMPDU that the STA can receive.
@@ -922,12 +928,17 @@ struct ieee80211_ht_info {
 #define IEEE80211_MAX_AMPDU_BUF 0x40
 
 
-/* Spatial Multiplexing Power Save Modes */
+/* Spatial Multiplexing Power Save Modes (for capability) */
 #define WLAN_HT_CAP_SM_PS_STATIC	0
 #define WLAN_HT_CAP_SM_PS_DYNAMIC	1
 #define WLAN_HT_CAP_SM_PS_INVALID	2
 #define WLAN_HT_CAP_SM_PS_DISABLED	3
 
+/* for SM power control field lower two bits */
+#define WLAN_HT_SMPS_CONTROL_DISABLED	0
+#define WLAN_HT_SMPS_CONTROL_STATIC	1
+#define WLAN_HT_SMPS_CONTROL_DYNAMIC	3
+
 /* Authentication algorithms */
 #define WLAN_AUTH_OPEN 0
 #define WLAN_AUTH_SHARED_KEY 1
@@ -1150,6 +1161,18 @@ enum ieee80211_spectrum_mgmt_actioncode {
 	WLAN_ACTION_SPCT_CHL_SWITCH = 4,
 };
 
+/* HT action codes */
+enum ieee80211_ht_actioncode {
+	WLAN_HT_ACTION_NOTIFY_CHANWIDTH = 0,
+	WLAN_HT_ACTION_SMPS = 1,
+	WLAN_HT_ACTION_PSMP = 2,
+	WLAN_HT_ACTION_PCO_PHASE = 3,
+	WLAN_HT_ACTION_CSI = 4,
+	WLAN_HT_ACTION_NONCOMPRESSED_BF = 5,
+	WLAN_HT_ACTION_COMPRESSED_BF = 6,
+	WLAN_HT_ACTION_ASEL_IDX_FEEDBACK = 7,
+};
+
 /* Security key length */
 enum ieee80211_key_len {
 	WLAN_KEY_LEN_WEP40 = 5,

include/net/mac80211.h

@@ -597,8 +597,10 @@ enum ieee80211_conf_flags {
  * @IEEE80211_CONF_CHANGE_CHANNEL: the channel/channel_type changed
  * @IEEE80211_CONF_CHANGE_RETRY_LIMITS: retry limits changed
  * @IEEE80211_CONF_CHANGE_IDLE: Idle flag changed
+ * @IEEE80211_CONF_CHANGE_SMPS: Spatial multiplexing powersave mode changed
  */
 enum ieee80211_conf_changed {
+	IEEE80211_CONF_CHANGE_SMPS		= BIT(1),
 	IEEE80211_CONF_CHANGE_LISTEN_INTERVAL	= BIT(2),
 	IEEE80211_CONF_CHANGE_MONITOR		= BIT(3),
 	IEEE80211_CONF_CHANGE_PS		= BIT(4),
@@ -608,6 +610,21 @@ enum ieee80211_conf_changed {
 	IEEE80211_CONF_CHANGE_IDLE		= BIT(8),
 };
 
+/**
+ * enum ieee80211_smps_mode - spatial multiplexing power save mode
+ *
+ * @
+ */
+enum ieee80211_smps_mode {
+	IEEE80211_SMPS_AUTOMATIC,
+	IEEE80211_SMPS_OFF,
+	IEEE80211_SMPS_STATIC,
+	IEEE80211_SMPS_DYNAMIC,
+
+	/* keep last */
+	IEEE80211_SMPS_NUM_MODES,
+};
+
 /**
  * struct ieee80211_conf - configuration of the device
  *
@@ -636,6 +653,10 @@ enum ieee80211_conf_changed {
  * @short_frame_max_tx_count: Maximum number of transmissions for a "short"
  *    frame, called "dot11ShortRetryLimit" in 802.11, but actually means the
  *    number of transmissions not the number of retries
+ *
+ * @smps_mode: spatial multiplexing powersave mode; note that
+ *	%IEEE80211_SMPS_STATIC is used when the device is not
+ *	configured for an HT channel
  */
 struct ieee80211_conf {
 	u32 flags;
@@ -648,6 +669,7 @@ struct ieee80211_conf {
 
 	struct ieee80211_channel *channel;
 	enum nl80211_channel_type channel_type;
+	enum ieee80211_smps_mode smps_mode;
 };
 
 /**
@@ -930,6 +952,16 @@ enum ieee80211_tkip_key_type {
  * @IEEE80211_HW_BEACON_FILTER:
  *	Hardware supports dropping of irrelevant beacon frames to
  *	avoid waking up cpu.
+ *
+ * @IEEE80211_HW_SUPPORTS_STATIC_SMPS:
+ *	Hardware supports static spatial multiplexing powersave,
+ *	ie. can turn off all but one chain even on HT connections
+ *	that should be using more chains.
+ *
+ * @IEEE80211_HW_SUPPORTS_DYNAMIC_SMPS:
+ *	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.
  */
 enum ieee80211_hw_flags {
 	IEEE80211_HW_HAS_RATE_CONTROL			= 1<<0,
@@ -947,6 +979,8 @@ enum ieee80211_hw_flags {
 	IEEE80211_HW_SUPPORTS_DYNAMIC_PS		= 1<<12,
 	IEEE80211_HW_MFP_CAPABLE			= 1<<13,
 	IEEE80211_HW_BEACON_FILTER			= 1<<14,
+	IEEE80211_HW_SUPPORTS_STATIC_SMPS		= 1<<15,
+	IEEE80211_HW_SUPPORTS_DYNAMIC_SMPS		= 1<<16,
 };
 
 /**
@@ -1214,6 +1248,31 @@ ieee80211_get_alt_retry_rate(const struct ieee80211_hw *hw,
  * signal strength threshold checking.
  */
 
+/**
+ * DOC: Spatial multiplexing power save
+ *
+ * SMPS (Spatial multiplexing power save) is a mechanism to conserve
+ * power in an 802.11n implementation. For details on the mechanism
+ * and rationale, please refer to 802.11 (as amended by 802.11n-2009)
+ * "11.2.3 SM power save".
+ *
+ * The mac80211 implementation is capable of sending action frames
+ * to update the AP about the station's SMPS mode, and will instruct
+ * the driver to enter the specific mode. It will also announce the
+ * requested SMPS mode during the association handshake. Hardware
+ * support for this feature is required, and can be indicated by
+ * hardware flags.
+ *
+ * The default mode will be "automatic", which nl80211/cfg80211
+ * defines to be dynamic SMPS in (regular) powersave, and SMPS
+ * turned off otherwise.
+ *
+ * To support this feature, the driver must set the appropriate
+ * hardware support flags, and handle the SMPS flag to the config()
+ * operation. It will then with this mechanism be instructed to
+ * enter the requested SMPS mode while associated to an HT AP.
+ */
+
 /**
  * DOC: Frame filtering
  *

net/mac80211/cfg.c

@@ -1318,6 +1318,50 @@ static int ieee80211_testmode_cmd(struct wiphy *wiphy, void *data, int len)
 }
 #endif
 
+int __ieee80211_request_smps(struct ieee80211_sub_if_data *sdata,
+			     enum ieee80211_smps_mode smps_mode)
+{
+	const u8 *ap;
+	enum ieee80211_smps_mode old_req;
+	int err;
+
+	old_req = sdata->u.mgd.req_smps;
+	sdata->u.mgd.req_smps = smps_mode;
+
+	if (old_req == smps_mode &&
+	    smps_mode != IEEE80211_SMPS_AUTOMATIC)
+		return 0;
+
+	/*
+	 * If not associated, or current association is not an HT
+	 * association, there's no need to send an action frame.
+	 */
+	if (!sdata->u.mgd.associated ||
+	    sdata->local->oper_channel_type == NL80211_CHAN_NO_HT) {
+		mutex_lock(&sdata->local->iflist_mtx);
+		ieee80211_recalc_smps(sdata->local, sdata);
+		mutex_unlock(&sdata->local->iflist_mtx);
+		return 0;
+	}
+
+	ap = sdata->u.mgd.associated->cbss.bssid;
+
+	if (smps_mode == IEEE80211_SMPS_AUTOMATIC) {
+		if (sdata->u.mgd.powersave)
+			smps_mode = IEEE80211_SMPS_DYNAMIC;
+		else
+			smps_mode = IEEE80211_SMPS_OFF;
+	}
+
+	/* send SM PS frame to AP */
+	err = ieee80211_send_smps_action(sdata, smps_mode,
+					 ap, ap);
+	if (err)
+		sdata->u.mgd.req_smps = old_req;
+
+	return err;
+}
+
 static int ieee80211_set_power_mgmt(struct wiphy *wiphy, struct net_device *dev,
 				    bool enabled, int timeout)
 {
@@ -1335,6 +1379,11 @@ static int ieee80211_set_power_mgmt(struct wiphy *wiphy, struct net_device *dev,
 	sdata->u.mgd.powersave = enabled;
 	conf->dynamic_ps_timeout = timeout;
 
+	/* no change, but if automatic follow powersave */
+	mutex_lock(&sdata->u.mgd.mtx);
+	__ieee80211_request_smps(sdata, sdata->u.mgd.req_smps);
+	mutex_unlock(&sdata->u.mgd.mtx);
+
 	if (local->hw.flags & IEEE80211_HW_SUPPORTS_DYNAMIC_PS)
 		ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
 

net/mac80211/debugfs_netdev.c

@@ -41,6 +41,30 @@ static ssize_t ieee80211_if_read(
 	return ret;
 }
 
+static ssize_t ieee80211_if_write(
+	struct ieee80211_sub_if_data *sdata,
+	const char __user *userbuf,
+	size_t count, loff_t *ppos,
+	ssize_t (*write)(struct ieee80211_sub_if_data *, const char *, int))
+{
+	u8 *buf;
+	ssize_t ret = -ENODEV;
+
+	buf = kzalloc(count, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	if (copy_from_user(buf, userbuf, count))
+		return -EFAULT;
+
+	rtnl_lock();
+	if (sdata->dev->reg_state == NETREG_REGISTERED)
+		ret = (*write)(sdata, buf, count);
+	rtnl_unlock();
+
+	return ret;
+}
+
 #define IEEE80211_IF_FMT(name, field, format_string)			\
 static ssize_t ieee80211_if_fmt_##name(					\
 	const struct ieee80211_sub_if_data *sdata, char *buf,		\
@@ -71,7 +95,7 @@ static ssize_t ieee80211_if_fmt_##name(					\
 	return scnprintf(buf, buflen, "%pM\n", sdata->field);		\
 }
 
-#define __IEEE80211_IF_FILE(name)					\
+#define __IEEE80211_IF_FILE(name, _write)				\
 static ssize_t ieee80211_if_read_##name(struct file *file,		\
 					char __user *userbuf,		\
 					size_t count, loff_t *ppos)	\
@@ -82,12 +106,24 @@ static ssize_t ieee80211_if_read_##name(struct file *file,		\
 }									\
 static const struct file_operations name##_ops = {			\
 	.read = ieee80211_if_read_##name,				\
+	.write = (_write),						\
 	.open = mac80211_open_file_generic,				\
 }
 
+#define __IEEE80211_IF_FILE_W(name)					\
+static ssize_t ieee80211_if_write_##name(struct file *file,		\
+					 const char __user *userbuf,	\
+					 size_t count, loff_t *ppos)	\
+{									\
+	return ieee80211_if_write(file->private_data, userbuf, count,	\
+				  ppos, ieee80211_if_parse_##name);	\
+}									\
+__IEEE80211_IF_FILE(name, ieee80211_if_write_##name)
+
+
 #define IEEE80211_IF_FILE(name, field, format)				\
 		IEEE80211_IF_FMT_##format(name, field)			\
-		__IEEE80211_IF_FILE(name)
+		__IEEE80211_IF_FILE(name, NULL)
 
 /* common attributes */
 IEEE80211_IF_FILE(drop_unencrypted, drop_unencrypted, DEC);
@@ -99,6 +135,70 @@ IEEE80211_IF_FILE(bssid, u.mgd.bssid, MAC);
 IEEE80211_IF_FILE(aid, u.mgd.aid, DEC);
 IEEE80211_IF_FILE(capab, u.mgd.capab, HEX);
 
+static int ieee80211_set_smps(struct ieee80211_sub_if_data *sdata,
+			      enum ieee80211_smps_mode smps_mode)
+{
+	struct ieee80211_local *local = sdata->local;
+	int err;
+
+	if (!(local->hw.flags & IEEE80211_HW_SUPPORTS_STATIC_SMPS) &&
+	    smps_mode == IEEE80211_SMPS_STATIC)
+		return -EINVAL;
+
+	/* auto should be dynamic if in PS mode */
+	if (!(local->hw.flags & IEEE80211_HW_SUPPORTS_DYNAMIC_SMPS) &&
+	    (smps_mode == IEEE80211_SMPS_DYNAMIC ||
+	     smps_mode == IEEE80211_SMPS_AUTOMATIC))
+		return -EINVAL;
+
+	/* supported only on managed interfaces for now */
+	if (sdata->vif.type != NL80211_IFTYPE_STATION)
+		return -EOPNOTSUPP;
+
+	mutex_lock(&local->iflist_mtx);
+	err = __ieee80211_request_smps(sdata, smps_mode);
+	mutex_unlock(&local->iflist_mtx);
+
+	return err;
+}
+
+static const char *smps_modes[IEEE80211_SMPS_NUM_MODES] = {
+	[IEEE80211_SMPS_AUTOMATIC] = "auto",
+	[IEEE80211_SMPS_OFF] = "off",
+	[IEEE80211_SMPS_STATIC] = "static",
+	[IEEE80211_SMPS_DYNAMIC] = "dynamic",
+};
+
+static ssize_t ieee80211_if_fmt_smps(const struct ieee80211_sub_if_data *sdata,
+				     char *buf, int buflen)
+{
+	if (sdata->vif.type != NL80211_IFTYPE_STATION)
+		return -EOPNOTSUPP;
+
+	return snprintf(buf, buflen, "request: %s\nused: %s\n",
+			smps_modes[sdata->u.mgd.req_smps],
+			smps_modes[sdata->u.mgd.ap_smps]);
+}
+
+static ssize_t ieee80211_if_parse_smps(struct ieee80211_sub_if_data *sdata,
+				       const char *buf, int buflen)
+{
+	enum ieee80211_smps_mode mode;
+
+	for (mode = 0; mode < IEEE80211_SMPS_NUM_MODES; mode++) {
+		if (strncmp(buf, smps_modes[mode], buflen) == 0) {
+			int err = ieee80211_set_smps(sdata, mode);
+			if (!err)
+				return buflen;
+			return err;
+		}
+	}
+
+	return -EINVAL;
+}
+
+__IEEE80211_IF_FILE_W(smps);
+
 /* AP attributes */
 IEEE80211_IF_FILE(num_sta_ps, u.ap.num_sta_ps, ATOMIC);
 IEEE80211_IF_FILE(dtim_count, u.ap.dtim_count, DEC);
@@ -109,7 +209,7 @@ static ssize_t ieee80211_if_fmt_num_buffered_multicast(
 	return scnprintf(buf, buflen, "%u\n",
 			 skb_queue_len(&sdata->u.ap.ps_bc_buf));
 }
-__IEEE80211_IF_FILE(num_buffered_multicast);
+__IEEE80211_IF_FILE(num_buffered_multicast, NULL);
 
 /* WDS attributes */
 IEEE80211_IF_FILE(peer, u.wds.remote_addr, MAC);
@@ -158,6 +258,10 @@ IEEE80211_IF_FILE(dot11MeshHWMPRootMode,
 	debugfs_create_file(#name, 0400, sdata->debugfs.dir, \
 			    sdata, &name##_ops);
 
+#define DEBUGFS_ADD_MODE(name, mode) \
+	debugfs_create_file(#name, mode, sdata->debugfs.dir, \
+			    sdata, &name##_ops);
+
 static void add_sta_files(struct ieee80211_sub_if_data *sdata)
 {
 	DEBUGFS_ADD(drop_unencrypted, sta);
@@ -167,6 +271,7 @@ static void add_sta_files(struct ieee80211_sub_if_data *sdata)
 	DEBUGFS_ADD(bssid, sta);
 	DEBUGFS_ADD(aid, sta);
 	DEBUGFS_ADD(capab, sta);
+	DEBUGFS_ADD_MODE(smps, 0600);
 }
 
 static void add_ap_files(struct ieee80211_sub_if_data *sdata)

net/mac80211/driver-trace.h

@@ -140,6 +140,7 @@ TRACE_EVENT(drv_config,
 		__field(u8, short_frame_max_tx_count)
 		__field(int, center_freq)
 		__field(int, channel_type)
+		__field(int, smps)
 	),
 
 	TP_fast_assign(
@@ -155,6 +156,7 @@ TRACE_EVENT(drv_config,
 		__entry->short_frame_max_tx_count = local->hw.conf.short_frame_max_tx_count;
 		__entry->center_freq = local->hw.conf.channel->center_freq;
 		__entry->channel_type = local->hw.conf.channel_type;
+		__entry->smps = local->hw.conf.smps_mode;
 	),
 
 	TP_printk(

net/mac80211/ht.c

@@ -166,3 +166,50 @@ void ieee80211_process_delba(struct ieee80211_sub_if_data *sdata,
 		spin_unlock_bh(&sta->lock);
 	}
 }
+
+int ieee80211_send_smps_action(struct ieee80211_sub_if_data *sdata,
+			       enum ieee80211_smps_mode smps, const u8 *da,
+			       const u8 *bssid)
+{
+	struct ieee80211_local *local = sdata->local;
+	struct sk_buff *skb;
+	struct ieee80211_mgmt *action_frame;
+
+	/* 27 = header + category + action + smps mode */
+	skb = dev_alloc_skb(27 + local->hw.extra_tx_headroom);
+	if (!skb)
+		return -ENOMEM;
+
+	skb_reserve(skb, local->hw.extra_tx_headroom);
+	action_frame = (void *)skb_put(skb, 27);
+	memcpy(action_frame->da, da, ETH_ALEN);
+	memcpy(action_frame->sa, sdata->dev->dev_addr, ETH_ALEN);
+	memcpy(action_frame->bssid, bssid, ETH_ALEN);
+	action_frame->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
+						  IEEE80211_STYPE_ACTION);
+	action_frame->u.action.category = WLAN_CATEGORY_HT;
+	action_frame->u.action.u.ht_smps.action = WLAN_HT_ACTION_SMPS;
+	switch (smps) {
+	case IEEE80211_SMPS_AUTOMATIC:
+	case IEEE80211_SMPS_NUM_MODES:
+		WARN_ON(1);
+	case IEEE80211_SMPS_OFF:
+		action_frame->u.action.u.ht_smps.smps_control =
+				WLAN_HT_SMPS_CONTROL_DISABLED;
+		break;
+	case IEEE80211_SMPS_STATIC:
+		action_frame->u.action.u.ht_smps.smps_control =
+				WLAN_HT_SMPS_CONTROL_STATIC;
+		break;
+	case IEEE80211_SMPS_DYNAMIC:
+		action_frame->u.action.u.ht_smps.smps_control =
+				WLAN_HT_SMPS_CONTROL_DYNAMIC;
+		break;
+	}
+
+	/* we'll do more on status of this frame */
+	IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_CTL_REQ_TX_STATUS;
+	ieee80211_tx_skb(sdata, skb);
+
+	return 0;
+}

net/mac80211/ieee80211_i.h

@@ -297,6 +297,8 @@ struct ieee80211_if_managed {
 
 	unsigned long timers_running; /* used for quiesce/restart */
 	bool powersave; /* powersave requested for this iface */
+	enum ieee80211_smps_mode req_smps, /* requested smps mode */
+				 ap_smps; /* smps mode AP thinks we're in */
 
 	unsigned long request;
 
@@ -587,6 +589,9 @@ struct ieee80211_local {
 	/* used for uploading changed mc list */
 	struct work_struct reconfig_filter;
 
+	/* used to reconfigure hardware SM PS */
+	struct work_struct recalc_smps;
+
 	/* aggregated multicast list */
 	struct dev_addr_list *mc_list;
 	int mc_count;
@@ -760,6 +765,8 @@ struct ieee80211_local {
 	int user_power_level; /* in dBm */
 	int power_constr_level; /* in dBm */
 
+	enum ieee80211_smps_mode smps_mode;
+
 	struct work_struct restart_work;
 
 #ifdef CONFIG_MAC80211_DEBUGFS
@@ -978,6 +985,9 @@ void ieee80211_send_bar(struct ieee80211_sub_if_data *sdata, u8 *ra, u16 tid, u1
 void ieee80211_send_delba(struct ieee80211_sub_if_data *sdata,
 			  const u8 *da, u16 tid,
 			  u16 initiator, u16 reason_code);
+int ieee80211_send_smps_action(struct ieee80211_sub_if_data *sdata,
+			       enum ieee80211_smps_mode smps, const u8 *da,
+			       const u8 *bssid);
 
 void ieee80211_sta_stop_rx_ba_session(struct ieee80211_sub_if_data *sdata, u8 *da,
 				u16 tid, u16 initiator, u16 reason);
@@ -1088,6 +1098,10 @@ void ieee80211_sta_def_wmm_params(struct ieee80211_sub_if_data *sdata,
 u32 ieee80211_sta_get_rates(struct ieee80211_local *local,
 			    struct ieee802_11_elems *elems,
 			    enum ieee80211_band band);
+int __ieee80211_request_smps(struct ieee80211_sub_if_data *sdata,
+			     enum ieee80211_smps_mode smps_mode);
+void ieee80211_recalc_smps(struct ieee80211_local *local,
+			   struct ieee80211_sub_if_data *forsdata);
 
 #ifdef CONFIG_MAC80211_NOINLINE
 #define debug_noinline noinline

net/mac80211/main.c

@@ -113,6 +113,18 @@ int ieee80211_hw_config(struct ieee80211_local *local, u32 changed)
 		changed |= IEEE80211_CONF_CHANGE_CHANNEL;
 	}
 
+	if (!conf_is_ht(&local->hw.conf)) {
+		/*
+		 * mac80211.h documents that this is only valid
+		 * when the channel is set to an HT type, and
+		 * that otherwise STATIC is used.
+		 */
+		local->hw.conf.smps_mode = IEEE80211_SMPS_STATIC;
+	} else if (local->hw.conf.smps_mode != local->smps_mode) {
+		local->hw.conf.smps_mode = local->smps_mode;
+		changed |= IEEE80211_CONF_CHANGE_SMPS;
+	}
+
 	if (scan_chan)
 		power = chan->max_power;
 	else
@@ -297,6 +309,16 @@ void ieee80211_restart_hw(struct ieee80211_hw *hw)
 }
 EXPORT_SYMBOL(ieee80211_restart_hw);
 
+static void ieee80211_recalc_smps_work(struct work_struct *work)
+{
+	struct ieee80211_local *local =
+		container_of(work, struct ieee80211_local, recalc_smps);
+
+	mutex_lock(&local->iflist_mtx);
+	ieee80211_recalc_smps(local, NULL);
+	mutex_unlock(&local->iflist_mtx);
+}
+
 struct ieee80211_hw *ieee80211_alloc_hw(size_t priv_data_len,
 					const struct ieee80211_ops *ops)
 {
@@ -370,6 +392,8 @@ struct ieee80211_hw *ieee80211_alloc_hw(size_t priv_data_len,
 	INIT_WORK(&local->restart_work, ieee80211_restart_work);
 
 	INIT_WORK(&local->reconfig_filter, ieee80211_reconfig_filter);
+	INIT_WORK(&local->recalc_smps, ieee80211_recalc_smps_work);
+	local->smps_mode = IEEE80211_SMPS_OFF;
 
 	INIT_WORK(&local->dynamic_ps_enable_work,
 		  ieee80211_dynamic_ps_enable_work);

net/mac80211/mlme.c

@@ -398,6 +398,8 @@ static void ieee80211_send_assoc(struct ieee80211_sub_if_data *sdata,
 		__le16 tmp;
 		u32 flags = local->hw.conf.channel->flags;
 
+		/* determine capability flags */
+
 		switch (ht_info->ht_param & IEEE80211_HT_PARAM_CHA_SEC_OFFSET) {
 		case IEEE80211_HT_PARAM_CHA_SEC_ABOVE:
 			if (flags & IEEE80211_CHAN_NO_HT40PLUS) {
@@ -413,17 +415,64 @@ static void ieee80211_send_assoc(struct ieee80211_sub_if_data *sdata,
 			break;
 		}
 
-		tmp = cpu_to_le16(cap);
-		pos = skb_put(skb, sizeof(struct ieee80211_ht_cap)+2);
+		/* set SM PS mode properly */
+		cap &= ~IEEE80211_HT_CAP_SM_PS;
+		/* new association always uses requested smps mode */
+		if (ifmgd->req_smps == IEEE80211_SMPS_AUTOMATIC) {
+			if (ifmgd->powersave)
+				ifmgd->ap_smps = IEEE80211_SMPS_DYNAMIC;
+			else
+				ifmgd->ap_smps = IEEE80211_SMPS_OFF;
+		} else
+			ifmgd->ap_smps = ifmgd->req_smps;
+
+		switch (ifmgd->ap_smps) {
+		case IEEE80211_SMPS_AUTOMATIC:
+		case IEEE80211_SMPS_NUM_MODES:
+			WARN_ON(1);
+		case IEEE80211_SMPS_OFF:
+			cap |= WLAN_HT_CAP_SM_PS_DISABLED <<
+				IEEE80211_HT_CAP_SM_PS_SHIFT;
+			break;
+		case IEEE80211_SMPS_STATIC:
+			cap |= WLAN_HT_CAP_SM_PS_STATIC <<
+				IEEE80211_HT_CAP_SM_PS_SHIFT;
+			break;
+		case IEEE80211_SMPS_DYNAMIC:
+			cap |= WLAN_HT_CAP_SM_PS_DYNAMIC <<
+				IEEE80211_HT_CAP_SM_PS_SHIFT;
+			break;
+		}
+
+		/* reserve and fill IE */
+
+		pos = skb_put(skb, sizeof(struct ieee80211_ht_cap) + 2);
 		*pos++ = WLAN_EID_HT_CAPABILITY;
 		*pos++ = sizeof(struct ieee80211_ht_cap);
 		memset(pos, 0, sizeof(struct ieee80211_ht_cap));
+
+		/* capability flags */
+		tmp = cpu_to_le16(cap);
 		memcpy(pos, &tmp, sizeof(u16));
 		pos += sizeof(u16);
-		/* TODO: needs a define here for << 2 */
+
+		/* AMPDU parameters */
 		*pos++ = sband->ht_cap.ampdu_factor |
-			 (sband->ht_cap.ampdu_density << 2);
+			 (sband->ht_cap.ampdu_density <<
+				IEEE80211_HT_AMPDU_PARM_DENSITY_SHIFT);
+
+		/* MCS set */
 		memcpy(pos, &sband->ht_cap.mcs, sizeof(sband->ht_cap.mcs));
+		pos += sizeof(sband->ht_cap.mcs);
+
+		/* extended capabilities */
+		pos += sizeof(__le16);
+
+		/* BF capabilities */
+		pos += sizeof(__le32);
+
+		/* antenna selection */
+		pos += sizeof(u8);
 	}
 
 	IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT;
@@ -932,6 +981,7 @@ static void ieee80211_set_associated(struct ieee80211_sub_if_data *sdata,
 
 	mutex_lock(&local->iflist_mtx);
 	ieee80211_recalc_ps(local, -1);
+	ieee80211_recalc_smps(local, sdata);
 	mutex_unlock(&local->iflist_mtx);
 
 	netif_start_queue(sdata->dev);
@@ -2327,6 +2377,11 @@ void ieee80211_sta_setup_sdata(struct ieee80211_sub_if_data *sdata)
 		ifmgd->flags |= IEEE80211_STA_WMM_ENABLED;
 
 	mutex_init(&ifmgd->mtx);
+
+	if (sdata->local->hw.flags & IEEE80211_HW_SUPPORTS_DYNAMIC_SMPS)
+		ifmgd->req_smps = IEEE80211_SMPS_AUTOMATIC;
+	else
+		ifmgd->req_smps = IEEE80211_SMPS_OFF;
 }
 
 /* scan finished notification */

net/mac80211/status.c

@@ -134,6 +134,40 @@ static void ieee80211_handle_filtered_frame(struct ieee80211_local *local,
 	dev_kfree_skb(skb);
 }
 
+static void ieee80211_frame_acked(struct sta_info *sta, struct sk_buff *skb)
+{
+	struct ieee80211_mgmt *mgmt = (void *) skb->data;
+	struct ieee80211_local *local = sta->local;
+	struct ieee80211_sub_if_data *sdata = sta->sdata;
+
+	if (ieee80211_is_action(mgmt->frame_control) &&
+	    sdata->vif.type == NL80211_IFTYPE_STATION &&
+	    mgmt->u.action.category == WLAN_CATEGORY_HT &&
+	    mgmt->u.action.u.ht_smps.action == WLAN_HT_ACTION_SMPS) {
+		/*
+		 * This update looks racy, but isn't -- if we come
+		 * here we've definitely got a station that we're
+		 * talking to, and on a managed interface that can
+		 * only be the AP. And the only other place updating
+		 * this variable is before we're associated.
+		 */
+		switch (mgmt->u.action.u.ht_smps.smps_control) {
+		case WLAN_HT_SMPS_CONTROL_DYNAMIC:
+			sta->sdata->u.mgd.ap_smps = IEEE80211_SMPS_DYNAMIC;
+			break;
+		case WLAN_HT_SMPS_CONTROL_STATIC:
+			sta->sdata->u.mgd.ap_smps = IEEE80211_SMPS_STATIC;
+			break;
+		case WLAN_HT_SMPS_CONTROL_DISABLED:
+		default: /* shouldn't happen since we don't send that */
+			sta->sdata->u.mgd.ap_smps = IEEE80211_SMPS_OFF;
+			break;
+		}
+
+		ieee80211_queue_work(&local->hw, &local->recalc_smps);
+	}
+}
+
 void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
 {
 	struct sk_buff *skb2;
@@ -210,6 +244,10 @@ void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
 		rate_control_tx_status(local, sband, sta, skb);
 		if (ieee80211_vif_is_mesh(&sta->sdata->vif))
 			ieee80211s_update_metric(local, sta, skb);
+
+		if (!(info->flags & IEEE80211_TX_CTL_INJECTED) &&
+		    (info->flags & IEEE80211_TX_STAT_ACK))
+			ieee80211_frame_acked(sta, skb);
 	}
 
 	rcu_read_unlock();

net/mac80211/util.c

@@ -1170,3 +1170,77 @@ int ieee80211_reconfig(struct ieee80211_local *local)
 	return 0;
 }
 
+static int check_mgd_smps(struct ieee80211_if_managed *ifmgd,
+			  enum ieee80211_smps_mode *smps_mode)
+{
+	if (ifmgd->associated) {
+		*smps_mode = ifmgd->ap_smps;
+
+		if (*smps_mode == IEEE80211_SMPS_AUTOMATIC) {
+			if (ifmgd->powersave)
+				*smps_mode = IEEE80211_SMPS_DYNAMIC;
+			else
+				*smps_mode = IEEE80211_SMPS_OFF;
+		}
+
+		return 1;
+	}
+
+	return 0;
+}
+
+/* must hold iflist_mtx */
+void ieee80211_recalc_smps(struct ieee80211_local *local,
+			   struct ieee80211_sub_if_data *forsdata)
+{
+	struct ieee80211_sub_if_data *sdata;
+	enum ieee80211_smps_mode smps_mode = IEEE80211_SMPS_OFF;
+	int count = 0;
+
+	if (forsdata)
+		WARN_ON(!mutex_is_locked(&forsdata->u.mgd.mtx));
+
+	WARN_ON(!mutex_is_locked(&local->iflist_mtx));
+
+	/*
+	 * This function could be improved to handle multiple
+	 * interfaces better, but right now it makes any
+	 * non-station interfaces force SM PS to be turned
+	 * off. If there are multiple station interfaces it
+	 * could also use the best possible mode, e.g. if
+	 * one is in static and the other in dynamic then
+	 * dynamic is ok.
+	 */
+
+	list_for_each_entry(sdata, &local->interfaces, list) {
+		if (!netif_running(sdata->dev))
+			continue;
+		if (sdata->vif.type != NL80211_IFTYPE_STATION)
+			goto set;
+		if (sdata != forsdata) {
+			/*
+			 * This nested is ok -- we are holding the iflist_mtx
+			 * so can't get here twice or so. But it's required
+			 * since normally we acquire it first and then the
+			 * iflist_mtx.
+			 */
+			mutex_lock_nested(&sdata->u.mgd.mtx, SINGLE_DEPTH_NESTING);
+			count += check_mgd_smps(&sdata->u.mgd, &smps_mode);
+			mutex_unlock(&sdata->u.mgd.mtx);
+		} else
+			count += check_mgd_smps(&sdata->u.mgd, &smps_mode);
+
+		if (count > 1) {
+			smps_mode = IEEE80211_SMPS_OFF;
+			break;
+		}
+	}
+
+	if (smps_mode == local->smps_mode)
+		return;
+
+ set:
+	local->smps_mode = smps_mode;
+	/* changed flag is auto-detected for this */
+	ieee80211_hw_config(local, 0);
+}