cfg80211: allow userspace to specify client P2P PS support

Legacy clients don't support P2P power save mechanisms, and thus
if a P2P GO has a legacy client connected to it, it has to make
some changes in the PS behavior.

To handle this, add an attribute to specify whether a station supports
P2P PS or not. If the attribute was not specified cfg80211 will assume
that station supports it for P2P GO interface, and does NOT support it
for AP interface, matching the current assumptions in the code.

Signed-off-by: Ayala Beker <ayala.beker@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/uapi/linux/nl80211.h

@@ -1804,6 +1804,9 @@ enum nl80211_commands {
  *	it contains the behaviour-specific attribute containing the parameters for
  *	BSS selection to be done by driver and/or firmware.
  *
+ * @NL80211_ATTR_STA_SUPPORT_P2P_PS: whether P2P PS mechanism supported
+ *	or not. u8, one of the values of &enum nl80211_sta_p2p_ps_status
+ *
  * @NUM_NL80211_ATTR: total number of nl80211_attrs available
  * @NL80211_ATTR_MAX: highest attribute number currently defined
  * @__NL80211_ATTR_AFTER_LAST: internal use
@@ -2182,6 +2185,8 @@ enum nl80211_attrs {
 
 	NL80211_ATTR_BSS_SELECT,
 
+	NL80211_ATTR_STA_SUPPORT_P2P_PS,
+
 	/* add attributes here, update the policy in nl80211.c */
 
 	__NL80211_ATTR_AFTER_LAST,
@@ -2325,6 +2330,20 @@ enum nl80211_sta_flags {
 	NL80211_STA_FLAG_MAX = __NL80211_STA_FLAG_AFTER_LAST - 1
 };
 
+/**
+ * enum nl80211_sta_p2p_ps_status - station support of P2P PS
+ *
+ * @NL80211_P2P_PS_UNSUPPORTED: station doesn't support P2P PS mechanism
+ * @@NL80211_P2P_PS_SUPPORTED: station supports P2P PS mechanism
+ * @NUM_NL80211_P2P_PS_STATUS: number of values
+ */
+enum nl80211_sta_p2p_ps_status {
+	NL80211_P2P_PS_UNSUPPORTED = 0,
+	NL80211_P2P_PS_SUPPORTED,
+
+	NUM_NL80211_P2P_PS_STATUS,
+};
+
 #define NL80211_STA_FLAG_MAX_OLD_API	NL80211_STA_FLAG_TDLS_PEER
 
 /**