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, 16 insertions, 0 deletions

diff --git a/drivers/net/wireless/rt2x00/rt2800lib.c b/drivers/net/wireless/rt2x00/rt2800lib.c
index afad3e1c1838..55727328e227 100644
--- a/drivers/net/wireless/rt2x00/rt2800lib.c
+++ b/drivers/net/wireless/rt2x00/rt2800lib.c
@@ -807,6 +807,15 @@ void rt2800_config_intf(struct rt2x00_dev *rt2x00dev, struct rt2x00_intf *intf,
                 rt2x00_set_field32(&reg, BCN_TIME_CFG_TBTT_ENABLE,
                                    (conf->sync == TSF_SYNC_BEACON));
                 rt2800_register_write(rt2x00dev, BCN_TIME_CFG, reg);
+
+                /*
+                 * Enable pre tbtt interrupt for beaconing modes
+                 */
+                rt2800_register_read(rt2x00dev, INT_TIMER_EN, &reg);
+                rt2x00_set_field32(&reg, INT_TIMER_EN_PRE_TBTT_TIMER,
+                                   (conf->sync == TSF_SYNC_BEACON));
+                rt2800_register_write(rt2x00dev, INT_TIMER_EN, reg);
+
         }
 
         if (flags & CONFIG_UPDATE_MAC) {
@@ -1732,6 +1741,13 @@ int rt2800_init_registers(struct rt2x00_dev *rt2x00dev)
         rt2800_register_read(rt2x00dev, TX_STA_CNT1, &reg);
         rt2800_register_read(rt2x00dev, TX_STA_CNT2, &reg);
 
+        /*
+         * Setup leadtime for pre tbtt interrupt to 6ms
+         */
+        rt2800_register_read(rt2x00dev, INT_TIMER_CFG, &reg);
+        rt2x00_set_field32(&reg, INT_TIMER_CFG_PRE_TBTT_TIMER, 6 << 4);
+        rt2800_register_write(rt2x00dev, INT_TIMER_CFG, reg);
+
         return 0;
 }
 EXPORT_SYMBOL_GPL(rt2800_init_registers);