mac80211: add HW flag for disabling auto link-PS in AP mode

When operating in AP mode the wl1271 hardware filters out null-data
packets as well as management packets. This makes it impossible for
mac80211 to monitor the PS mode by using the PM bit of incoming frames.

Implement a HW flag to indicate that mac80211 should ignore the PM bit.
In addition, expose ieee80211_sta_ps_transition() to make low-level
drivers capable of controlling PS-mode.

Signed-off-by: Arik Nemtsov <arik@wizery.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index d6b0045..0396cec 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -1069,6 +1069,13 @@
  *	to decrypt group addressed frames, then IBSS RSN support is still
  *	possible but software crypto will be used. Advertise the wiphy flag
  *	only in that case.
+ *
+ * @IEEE80211_HW_AP_LINK_PS: When operating in AP mode the device
+ *	autonomously manages the PS status of connected stations. When
+ *	this flag is set mac80211 will not trigger PS mode for connected
+ *	stations based on the PM bit of incoming frames.
+ *	Use ieee80211_start_ps()/ieee8021_end_ps() to manually configure
+ *	the PS mode of connected stations.
  */
 enum ieee80211_hw_flags {
 	IEEE80211_HW_HAS_RATE_CONTROL			= 1<<0,
@@ -1093,6 +1100,7 @@
 	IEEE80211_HW_CONNECTION_MONITOR			= 1<<19,
 	IEEE80211_HW_SUPPORTS_CQM_RSSI			= 1<<20,
 	IEEE80211_HW_SUPPORTS_PER_STA_GTK		= 1<<21,
+	IEEE80211_HW_AP_LINK_PS				= 1<<22,
 };
 
 /**
@@ -1701,7 +1709,9 @@
  *	station, AP, IBSS/WDS/mesh peer etc. This callback can sleep.
  *
  * @sta_notify: Notifies low level driver about power state transition of an
- *	associated station, AP,  IBSS/WDS/mesh peer etc. Must be atomic.
+ *	associated station, AP,  IBSS/WDS/mesh peer etc. For a VIF operating
+ *	in AP mode, this callback will not be called when the flag
+ *	%IEEE80211_HW_AP_LINK_PS is set. Must be atomic.
  *
  * @conf_tx: Configure TX queue parameters (EDCF (aifs, cw_min, cw_max),
  *	bursting) for a hardware TX queue.
@@ -2131,6 +2141,48 @@
 	local_bh_enable();
 }
 
+/**
+ * ieee80211_sta_ps_transition - PS transition for connected sta
+ *
+ * When operating in AP mode with the %IEEE80211_HW_AP_LINK_PS
+ * flag set, use this function to inform mac80211 about a connected station
+ * entering/leaving PS mode.
+ *
+ * This function may not be called in IRQ context or with softirqs enabled.
+ *
+ * Calls to this function for a single hardware must be synchronized against
+ * each other.
+ *
+ * The function returns -EINVAL when the requested PS mode is already set.
+ *
+ * @sta: currently connected sta
+ * @start: start or stop PS
+ */
+int ieee80211_sta_ps_transition(struct ieee80211_sta *sta, bool start);
+
+/**
+ * ieee80211_sta_ps_transition_ni - PS transition for connected sta
+ *                                  (in process context)
+ *
+ * Like ieee80211_sta_ps_transition() but can be called in process context
+ * (internally disables bottom halves). Concurrent call restriction still
+ * applies.
+ *
+ * @sta: currently connected sta
+ * @start: start or stop PS
+ */
+static inline int ieee80211_sta_ps_transition_ni(struct ieee80211_sta *sta,
+						  bool start)
+{
+	int ret;
+
+	local_bh_disable();
+	ret = ieee80211_sta_ps_transition(sta, start);
+	local_bh_enable();
+
+	return ret;
+}
+
 /*
  * The TX headroom reserved by mac80211 for its own tx_status functions.
  * This is enough for the radiotap header.