rt2x00: Use pretbtt irq for fetching beacons on rt2800pci

Updating the beacon on pre tbtt instead of beacondone allows much lower
latency in regard to TIM updates. Hence, use the pre tbtt interrupt for
updating the beacon in rt2800pci (older devices don't provide a pre tbtt
interrupt).

Also, add a new driver flag to indicate if a driver has pre tbtt support
or not and implement the according behavior in rt2x00lib.

Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com>
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 22 insertions, 4 deletions

diff --git a/drivers/net/wireless/rt2x00/rt2x00dev.c b/drivers/net/wireless/rt2x00/rt2x00dev.c
index ae0adff0b832..f59b9f7226a8 100644
--- a/drivers/net/wireless/rt2x00/rt2x00dev.c
+++ b/drivers/net/wireless/rt2x00/rt2x00dev.c
@@ -200,8 +200,8 @@ static void rt2x00lib_bc_buffer_iter(void *data, u8 *mac,
         }
 }
 
-static void rt2x00lib_beacondone_iter(void *data, u8 *mac,
-                                      struct ieee80211_vif *vif)
+static void rt2x00lib_beaconupdate_iter(void *data, u8 *mac,
+                                        struct ieee80211_vif *vif)
 {
         struct rt2x00_dev *rt2x00dev = data;
 
@@ -223,15 +223,33 @@ void rt2x00lib_beacondone(struct rt2x00_dev *rt2x00dev)
         ieee80211_iterate_active_interfaces(rt2x00dev->hw,
                                             rt2x00lib_bc_buffer_iter,
                                             rt2x00dev);
+        /*
+         * Devices with pre tbtt interrupt don't need to update the beacon
+         * here as they will fetch the next beacon directly prior to
+         * transmission.
+         */
+        if (test_bit(DRIVER_SUPPORT_PRE_TBTT_INTERRUPT, &rt2x00dev->flags))
+                return;
 
         /* fetch next beacon */
         ieee80211_iterate_active_interfaces(rt2x00dev->hw,
-                                            rt2x00lib_beacondone_iter,
+                                            rt2x00lib_beaconupdate_iter,
                                             rt2x00dev);
-
 }
 EXPORT_SYMBOL_GPL(rt2x00lib_beacondone);
 
+void rt2x00lib_pretbtt(struct rt2x00_dev *rt2x00dev)
+{
+        if (!test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags))
+                return;
+
+        /* fetch next beacon */
+        ieee80211_iterate_active_interfaces(rt2x00dev->hw,
+                                            rt2x00lib_beaconupdate_iter,
+                                            rt2x00dev);
+}
+EXPORT_SYMBOL_GPL(rt2x00lib_pretbtt);
+
 void rt2x00lib_txdone(struct queue_entry *entry,
                       struct txdone_entry_desc *txdesc)
 {