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>

1 files changed, 74 insertions, 0 deletions

diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index d54dbe8e09ba..086ef6257b4b 100644
--- a/net/mac80211/util.c
+++ b/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);
+}