mac80211: extend/document powersave API

This modifies hardware flags for powersave to support three different
flags:
 * IEEE80211_HW_SUPPORTS_PS - indicates general PS support
 * IEEE80211_HW_PS_NULLFUNC_STACK - indicates nullfunc sending in software
 * IEEE80211_HW_SUPPORTS_DYNAMIC_PS - indicates dynamic PS on the device

It also adds documentation for all this which explains how to set the
various flags.

Additionally, it fixes a few things:
 * a spot where && was used to test flags
 * enable CONF_PS only when associated again

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

11 files changed, 111 insertions, 46 deletions

diff --git a/Documentation/DocBook/mac80211.tmpl b/Documentation/DocBook/mac80211.tmpl
index bdf908a6e545..8af6d9626878 100644
--- a/Documentation/DocBook/mac80211.tmpl
+++ b/Documentation/DocBook/mac80211.tmpl
@@ -17,8 +17,7 @@
     </authorgroup>
 
     <copyright>
-      <year>2007</year>
-      <year>2008</year>
+      <year>2007-2009</year>
       <holder>Johannes Berg</holder>
     </copyright>
 
@@ -223,6 +222,11 @@ usage should require reading the full document.
 !Finclude/net/mac80211.h ieee80211_key_flags
     </chapter>
 
+    <chapter id="powersave">
+      <title>Powersave support</title>
+!Pinclude/net/mac80211.h Powersave support
+    </chapter>
+
     <chapter id="qos">
       <title>Multiple queues and QoS support</title>
       <para>TBD</para>
diff --git a/drivers/net/wireless/iwlwifi/iwl-core.c b/drivers/net/wireless/iwlwifi/iwl-core.c
index 76315c30e6fc..07c3870365be 100644
--- a/drivers/net/wireless/iwlwifi/iwl-core.c
+++ b/drivers/net/wireless/iwlwifi/iwl-core.c
@@ -805,7 +805,8 @@ int iwl_setup_mac(struct iwl_priv *priv)
         /* Tell mac80211 our characteristics */
         hw->flags = IEEE80211_HW_SIGNAL_DBM |
                     IEEE80211_HW_NOISE_DBM |
-                    IEEE80211_HW_AMPDU_AGGREGATION;
+                    IEEE80211_HW_AMPDU_AGGREGATION |
+                    IEEE80211_HW_SUPPORTS_PS;
         hw->wiphy->interface_modes =
                 BIT(NL80211_IFTYPE_STATION) |
                 BIT(NL80211_IFTYPE_ADHOC);
diff --git a/drivers/net/wireless/rt2x00/rt2400pci.c b/drivers/net/wireless/rt2x00/rt2400pci.c
index 9104113270d0..ae8bfd6b59df 100644
--- a/drivers/net/wireless/rt2x00/rt2400pci.c
+++ b/drivers/net/wireless/rt2x00/rt2400pci.c
@@ -1449,7 +1449,9 @@ static int rt2400pci_probe_hw_mode(struct rt2x00_dev *rt2x00dev)
          * Initialize all hw fields.
          */
         rt2x00dev->hw->flags = IEEE80211_HW_HOST_BROADCAST_PS_BUFFERING |
-                               IEEE80211_HW_SIGNAL_DBM;
+                               IEEE80211_HW_SIGNAL_DBM |
+                               IEEE80211_HW_SUPPORTS_PS |
+                               IEEE80211_HW_PS_NULLFUNC_STACK;
         rt2x00dev->hw->extra_tx_headroom = 0;
 
         SET_IEEE80211_DEV(rt2x00dev->hw, rt2x00dev->dev);
diff --git a/drivers/net/wireless/rt2x00/rt2500pci.c b/drivers/net/wireless/rt2x00/rt2500pci.c
index ebcc49770922..bca6798be153 100644
--- a/drivers/net/wireless/rt2x00/rt2500pci.c
+++ b/drivers/net/wireless/rt2x00/rt2500pci.c
@@ -1749,7 +1749,9 @@ static int rt2500pci_probe_hw_mode(struct rt2x00_dev *rt2x00dev)
          * Initialize all hw fields.
          */
         rt2x00dev->hw->flags = IEEE80211_HW_HOST_BROADCAST_PS_BUFFERING |
-                               IEEE80211_HW_SIGNAL_DBM;
+                               IEEE80211_HW_SIGNAL_DBM |
+                               IEEE80211_HW_SUPPORTS_PS |
+                               IEEE80211_HW_PS_NULLFUNC_STACK;
 
         rt2x00dev->hw->extra_tx_headroom = 0;
 
diff --git a/drivers/net/wireless/rt2x00/rt2500usb.c b/drivers/net/wireless/rt2x00/rt2500usb.c
index e992bad64644..27a6971df579 100644
--- a/drivers/net/wireless/rt2x00/rt2500usb.c
+++ b/drivers/net/wireless/rt2x00/rt2500usb.c
@@ -1801,7 +1801,9 @@ static int rt2500usb_probe_hw_mode(struct rt2x00_dev *rt2x00dev)
         rt2x00dev->hw->flags =
             IEEE80211_HW_RX_INCLUDES_FCS |
             IEEE80211_HW_HOST_BROADCAST_PS_BUFFERING |
-            IEEE80211_HW_SIGNAL_DBM;
+            IEEE80211_HW_SIGNAL_DBM |
+            IEEE80211_HW_SUPPORTS_PS |
+            IEEE80211_HW_PS_NULLFUNC_STACK;
 
         rt2x00dev->hw->extra_tx_headroom = TXD_DESC_SIZE;
 
diff --git a/drivers/net/wireless/rt2x00/rt61pci.c b/drivers/net/wireless/rt2x00/rt61pci.c
index 82d35a5a4aa7..549480a963e9 100644
--- a/drivers/net/wireless/rt2x00/rt61pci.c
+++ b/drivers/net/wireless/rt2x00/rt61pci.c
@@ -2556,7 +2556,9 @@ static int rt61pci_probe_hw_mode(struct rt2x00_dev *rt2x00dev)
          */
         rt2x00dev->hw->flags =
             IEEE80211_HW_HOST_BROADCAST_PS_BUFFERING |
-            IEEE80211_HW_SIGNAL_DBM;
+            IEEE80211_HW_SIGNAL_DBM |
+            IEEE80211_HW_SUPPORTS_PS |
+            IEEE80211_HW_PS_NULLFUNC_STACK;
         rt2x00dev->hw->extra_tx_headroom = 0;
 
         SET_IEEE80211_DEV(rt2x00dev->hw, rt2x00dev->dev);
diff --git a/drivers/net/wireless/rt2x00/rt73usb.c b/drivers/net/wireless/rt2x00/rt73usb.c
index 2b70c01b55e9..849220236c7d 100644
--- a/drivers/net/wireless/rt2x00/rt73usb.c
+++ b/drivers/net/wireless/rt2x00/rt73usb.c
@@ -2077,7 +2077,9 @@ static int rt73usb_probe_hw_mode(struct rt2x00_dev *rt2x00dev)
          */
         rt2x00dev->hw->flags =
             IEEE80211_HW_HOST_BROADCAST_PS_BUFFERING |
-            IEEE80211_HW_SIGNAL_DBM;
+            IEEE80211_HW_SIGNAL_DBM |
+            IEEE80211_HW_SUPPORTS_PS |
+            IEEE80211_HW_PS_NULLFUNC_STACK;
         rt2x00dev->hw->extra_tx_headroom = TXD_DESC_SIZE;
 
         SET_IEEE80211_DEV(rt2x00dev->hw, rt2x00dev->dev);
diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 83ee8a212296..8a305bfdb87b 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -850,10 +850,15 @@ enum ieee80211_tkip_key_type {
  * @IEEE80211_HW_AMPDU_AGGREGATION:
  *      Hardware supports 11n A-MPDU aggregation.
  *
- * @IEEE80211_HW_NO_STACK_DYNAMIC_PS:
- *      Hardware which has dynamic power save support, meaning
- *      that power save is enabled in idle periods, and don't need support
- *      from stack.
+ * @IEEE80211_HW_SUPPORTS_PS:
+ *      Hardware has power save support (i.e. can go to sleep).
+ *
+ * @IEEE80211_HW_PS_NULLFUNC_STACK:
+ *      Hardware requires nullfunc frame handling in stack, implies
+ *      stack support for dynamic PS.
+ *
+ * @IEEE80211_HW_SUPPORTS_DYNAMIC_PS:
+ *      Hardware has support for dynamic PS.
  */
 enum ieee80211_hw_flags {
         IEEE80211_HW_RX_INCLUDES_FCS                    = 1<<1,
@@ -866,7 +871,9 @@ enum ieee80211_hw_flags {
         IEEE80211_HW_NOISE_DBM                          = 1<<8,
         IEEE80211_HW_SPECTRUM_MGMT                      = 1<<9,
         IEEE80211_HW_AMPDU_AGGREGATION                  = 1<<10,
-        IEEE80211_HW_NO_STACK_DYNAMIC_PS                = 1<<11,
+        IEEE80211_HW_SUPPORTS_PS                        = 1<<11,
+        IEEE80211_HW_PS_NULLFUNC_STACK                  = 1<<12,
+        IEEE80211_HW_SUPPORTS_DYNAMIC_PS                = 1<<13,
 };
 
 /**
@@ -1053,6 +1060,42 @@ ieee80211_get_alt_retry_rate(const struct ieee80211_hw *hw,
  */
 
 /**
+ * DOC: Powersave support
+ *
+ * mac80211 has support for various powersave implementations.
+ *
+ * First, it can support hardware that handles all powersaving by
+ * itself, such hardware should simply set the %IEEE80211_HW_SUPPORTS_PS
+ * hardware flag. In that case, it will be told about the desired
+ * powersave mode depending on the association status, and the driver
+ * must take care of sending nullfunc frames when necessary, i.e. when
+ * entering and leaving powersave mode. The driver is required to look at
+ * the AID in beacons and signal to the AP that it woke up when it finds
+ * traffic directed to it. This mode supports dynamic PS by simply
+ * enabling/disabling PS.
+ *
+ * Additionally, such hardware may set the %IEEE80211_HW_SUPPORTS_DYNAMIC_PS
+ * flag to indicate that it can support dynamic PS mode itself (see below).
+ *
+ * Other hardware designs cannot send nullfunc frames by themselves and also
+ * need software support for parsing the TIM bitmap. This is also supported
+ * by mac80211 by combining the %IEEE80211_HW_SUPPORTS_PS and
+ * %IEEE80211_HW_PS_NULLFUNC_STACK flags. The hardware is of course still
+ * required to pass up beacons. Additionally, in this case, mac80211 will
+ * wake up the hardware when multicast traffic is announced in the beacon.
+ *
+ * FIXME: I don't think we can be fast enough in software when we want to
+ *        receive multicast traffic?
+ *
+ * Dynamic powersave mode is an extension to normal powersave mode in which
+ * the hardware stays awake for a user-specified period of time after sending
+ * a frame so that reply frames need not be buffered and therefore delayed
+ * to the next wakeup. This can either be supported by hardware, in which case
+ * the driver needs to look at the @dynamic_ps_timeout hardware configuration
+ * value, or by the stack if all nullfunc handling is in the stack.
+ */
+
+/**
  * DOC: Frame filtering
  *
  * mac80211 requires to see many management frames for proper
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 7709e7645671..a1e683e305f0 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -775,17 +775,17 @@ static void ieee80211_set_associated(struct ieee80211_sub_if_data *sdata,
         bss_info_changed |= BSS_CHANGED_BASIC_RATES;
         ieee80211_bss_info_change_notify(sdata, bss_info_changed);
 
-        if (local->powersave &&
-                        !(local->hw.flags & IEEE80211_HW_NO_STACK_DYNAMIC_PS)) {
-                if (local->hw.conf.dynamic_ps_timeout > 0)
+        if (local->powersave) {
+                if (!(local->hw.flags & IEEE80211_HW_SUPPORTS_DYNAMIC_PS) &&
+                    local->hw.conf.dynamic_ps_timeout > 0) {
                         mod_timer(&local->dynamic_ps_timer, jiffies +
                                   msecs_to_jiffies(
                                         local->hw.conf.dynamic_ps_timeout));
-                else {
-                        ieee80211_send_nullfunc(local, sdata, 1);
+                } else {
+                        if (local->hw.flags & IEEE80211_HW_PS_NULLFUNC_STACK)
+                                ieee80211_send_nullfunc(local, sdata, 1);
                         conf->flags |= IEEE80211_CONF_PS;
-                        ieee80211_hw_config(local,
-                                            IEEE80211_CONF_CHANGE_PS);
+                        ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
                 }
         }
 
@@ -1779,16 +1779,14 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
         ieee80211_sta_wmm_params(local, ifsta, elems.wmm_param,
                                  elems.wmm_param_len);
 
-        if (!(local->hw.flags & IEEE80211_HW_NO_STACK_DYNAMIC_PS)) {
+        if (local->hw.flags & IEEE80211_HW_PS_NULLFUNC_STACK &&
+            local->hw.conf.flags & IEEE80211_CONF_PS) {
                 directed_tim = check_tim(&elems, ifsta->aid, &is_mc);
 
                 if (directed_tim || is_mc) {
-                        if (local->hw.conf.flags && IEEE80211_CONF_PS) {
-                                local->hw.conf.flags &= ~IEEE80211_CONF_PS;
-                                ieee80211_hw_config(local,
-                                                IEEE80211_CONF_CHANGE_PS);
-                                ieee80211_send_nullfunc(local, sdata, 0);
-                        }
+                        local->hw.conf.flags &= ~IEEE80211_CONF_PS;
+                        ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
+                        ieee80211_send_nullfunc(local, sdata, 0);
                 }
         }
 
@@ -2694,9 +2692,10 @@ void ieee80211_dynamic_ps_enable_work(struct work_struct *work)
         if (local->hw.conf.flags & IEEE80211_CONF_PS)
                 return;
 
-        ieee80211_send_nullfunc(local, sdata, 1);
-        local->hw.conf.flags |= IEEE80211_CONF_PS;
+        if (local->hw.flags & IEEE80211_HW_PS_NULLFUNC_STACK)
+                ieee80211_send_nullfunc(local, sdata, 1);
 
+        local->hw.conf.flags |= IEEE80211_CONF_PS;
         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
 }
 
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index b18a72690119..cd6bc87eec73 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -1295,7 +1295,7 @@ int ieee80211_master_start_xmit(struct sk_buff *skb, struct net_device *dev)
                 return 0;
         }
 
-        if (!(local->hw.flags & IEEE80211_HW_NO_STACK_DYNAMIC_PS) &&
+        if ((local->hw.flags & IEEE80211_HW_PS_NULLFUNC_STACK) &&
             local->hw.conf.dynamic_ps_timeout > 0) {
                 if (local->hw.conf.flags & IEEE80211_CONF_PS) {
                         ieee80211_stop_queues_by_reason(&local->hw,
diff --git a/net/mac80211/wext.c b/net/mac80211/wext.c
index 3f2db0bda46c..1e5b29bdb3a7 100644
--- a/net/mac80211/wext.c
+++ b/net/mac80211/wext.c
@@ -837,6 +837,9 @@ static int ieee80211_ioctl_siwpower(struct net_device *dev,
         int ret = 0, timeout = 0;
         bool ps;
 
+        if (!(local->hw.flags & IEEE80211_HW_SUPPORTS_PS))
+                return -EOPNOTSUPP;
+
         if (sdata->vif.type != NL80211_IFTYPE_STATION)
                 return -EINVAL;
 
@@ -862,32 +865,37 @@ static int ieee80211_ioctl_siwpower(struct net_device *dev,
         if (wrq->flags & IW_POWER_TIMEOUT)
                 timeout = wrq->value / 1000;
 
-set:
+ set:
         if (ps == local->powersave && timeout == conf->dynamic_ps_timeout)
                 return ret;
 
         local->powersave = ps;
         conf->dynamic_ps_timeout = timeout;
 
-        if (local->hw.flags & IEEE80211_HW_NO_STACK_DYNAMIC_PS) {
+        if (local->hw.flags & IEEE80211_HW_SUPPORTS_DYNAMIC_PS)
                 ret = ieee80211_hw_config(local,
                                           IEEE80211_CONF_CHANGE_DYNPS_TIMEOUT);
-        } else if (sdata->u.sta.flags & IEEE80211_STA_ASSOCIATED) {
-                if (conf->dynamic_ps_timeout > 0)
-                        mod_timer(&local->dynamic_ps_timer, jiffies +
-                                  msecs_to_jiffies(conf->dynamic_ps_timeout));
-                else {
-                        if (local->powersave) {
+
+        if (!(sdata->u.sta.flags & IEEE80211_STA_ASSOCIATED))
+                return ret;
+
+        if (conf->dynamic_ps_timeout > 0 &&
+            !(local->hw.flags & IEEE80211_HW_SUPPORTS_DYNAMIC_PS)) {
+                mod_timer(&local->dynamic_ps_timer, jiffies +
+                          msecs_to_jiffies(conf->dynamic_ps_timeout));
+        } else {
+                if (local->powersave) {
+                        if (local->hw.flags & IEEE80211_HW_PS_NULLFUNC_STACK)
                                 ieee80211_send_nullfunc(local, sdata, 1);
-                                conf->flags |= IEEE80211_CONF_PS;
-                                ret = ieee80211_hw_config(local,
-                                                IEEE80211_CONF_CHANGE_PS);
-                        } else {
-                                conf->flags &= ~IEEE80211_CONF_PS;
-                                ret = ieee80211_hw_config(local,
-                                                IEEE80211_CONF_CHANGE_PS);
+                        conf->flags |= IEEE80211_CONF_PS;
+                        ret = ieee80211_hw_config(local,
+                                        IEEE80211_CONF_CHANGE_PS);
+                } else {
+                        conf->flags &= ~IEEE80211_CONF_PS;
+                        ret = ieee80211_hw_config(local,
+                                        IEEE80211_CONF_CHANGE_PS);
+                        if (local->hw.flags & IEEE80211_HW_PS_NULLFUNC_STACK)
                                 ieee80211_send_nullfunc(local, sdata, 0);
-                        }
                 }
         }