[rt2x00-users] [RFC 5/9] rt2x00: use pre tbtt interrupt on rt2800pci to fetch the next beacon

Helmut Schaa helmut.schaa at googlemail.com
Tue Jul 6 02:22:37 AEST 2010


Using the pre tbtt interrupt to update the beacon gives us the best latency
with regard to TIM and DTIM updates. Introduce a new driver flag that
indicated if a pre tbtt interrupt is available or not and use the pre tbtt
interrupt in 2800pci for updating the beacon.

Signed-off-by: Helmut Schaa <helmut.schaa at googlemail.com>
---
 drivers/net/wireless/rt2x00/rt2800.h    |    8 +++++++-
 drivers/net/wireless/rt2x00/rt2800lib.c |   16 ++++++++++++++++
 drivers/net/wireless/rt2x00/rt2800pci.c |   28 +++++++++++++++++++++++-----
 drivers/net/wireless/rt2x00/rt2x00.h    |    2 ++
 drivers/net/wireless/rt2x00/rt2x00dev.c |   26 ++++++++++++++++++++++----
 5 files changed, 70 insertions(+), 10 deletions(-)

diff --git a/drivers/net/wireless/rt2x00/rt2800.h b/drivers/net/wireless/rt2x00/rt2800.h
index 3ed87ba..35f6945 100644
--- a/drivers/net/wireless/rt2x00/rt2800.h
+++ b/drivers/net/wireless/rt2x00/rt2800.h
@@ -719,14 +719,20 @@
 #define TBTT_TIMER			0x1124
 
 /*
- * INT_TIMER_CFG:
+ * INT_TIMER_CFG: timer configuration
+ * PRE_TBTT_TIMER: leadtime to tbtt for pretbtt interrupt in units of 1/16 TU
+ * GP_TIMER: period of general purpose timer in units of 1/16 TU
  */
 #define INT_TIMER_CFG			0x1128
+#define INT_TIMER_CFG_PRE_TBTT_TIMER	FIELD32(0x0000ffff)
+#define INT_TIMER_CFG_GP_TIMER		FIELD32(0xffff0000)
 
 /*
  * INT_TIMER_EN: GP-timer and pre-tbtt Int enable
  */
 #define INT_TIMER_EN			0x112c
+#define INT_TIMER_EN_PRE_TBTT_TIMER	FIELD32(0x00000001)
+#define INT_TIMER_EN_GP_TIMER		FIELD32(0x00000002)
 
 /*
  * CH_IDLE_STA: channel idle time
diff --git a/drivers/net/wireless/rt2x00/rt2800lib.c b/drivers/net/wireless/rt2x00/rt2800lib.c
index d3cf0cc..fdfb653 100644
--- a/drivers/net/wireless/rt2x00/rt2800lib.c
+++ b/drivers/net/wireless/rt2x00/rt2800lib.c
@@ -762,6 +762,15 @@ 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) {
@@ -1638,6 +1647,13 @@ 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);
diff --git a/drivers/net/wireless/rt2x00/rt2800pci.c b/drivers/net/wireless/rt2x00/rt2800pci.c
index ea4362a..8c45527 100644
--- a/drivers/net/wireless/rt2x00/rt2800pci.c
+++ b/drivers/net/wireless/rt2x00/rt2800pci.c
@@ -924,20 +924,32 @@ static irqreturn_t rt2800pci_interrupt_thread(int irq, void *dev_instance)
 	u32 reg = rt2x00dev->irqvalue[0];
 
 	/*
-	 * 1 - Rx ring done interrupt.
+	 * 1 - Pre TBTT interrupt.
+	 */
+	if (rt2x00_get_field32(reg, INT_SOURCE_CSR_PRE_TBTT))
+		rt2x00lib_pretbtt(rt2x00dev);
+
+	/*
+	 * 2 - Beacondone interrupt.
+	 */
+	if (rt2x00_get_field32(reg, INT_SOURCE_CSR_TBTT))
+		rt2x00lib_beacondone(rt2x00dev);
+
+	/*
+	 * 3 - Rx ring done interrupt.
 	 */
 	if (rt2x00_get_field32(reg, INT_SOURCE_CSR_RX_DONE))
 		rt2x00pci_rxdone(rt2x00dev);
 
+	/*
+	 * 4 - Tx done interrupt.
+	 */
 	if (rt2x00_get_field32(reg, INT_SOURCE_CSR_TX_FIFO_STATUS))
 		rt2800pci_txdone(rt2x00dev);
 
 	/*
-	 * Current beacon was sent out, fetch the next one
+	 * 5 - Auto wakeup interrupt.
 	 */
-	if (rt2x00_get_field32(reg, INT_SOURCE_CSR_TBTT))
-		rt2x00lib_beacondone(rt2x00dev);
-
 	if (rt2x00_get_field32(reg, INT_SOURCE_CSR_AUTO_WAKEUP))
 		rt2800pci_wakeup(rt2x00dev);
 
@@ -1040,6 +1052,12 @@ static int rt2800pci_probe_hw(struct rt2x00_dev *rt2x00dev)
 	__set_bit(DRIVER_SUPPORT_CONTROL_FILTER_PSPOLL, &rt2x00dev->flags);
 
 	/*
+	 * This device has a pre tbtt interrupt and thus fetches
+	 * a new beacon directly prior to transmission.
+	 */
+	__set_bit(DRIVER_SUPPORT_PRE_TBTT_INTERRUPT, &rt2x00dev->flags);
+
+	/*
 	 * This device requires firmware.
 	 */
 	if (!rt2x00_is_soc(rt2x00dev))
diff --git a/drivers/net/wireless/rt2x00/rt2x00.h b/drivers/net/wireless/rt2x00/rt2x00.h
index 4b3d537..bf9fecc 100644
--- a/drivers/net/wireless/rt2x00/rt2x00.h
+++ b/drivers/net/wireless/rt2x00/rt2x00.h
@@ -651,6 +651,7 @@ enum rt2x00_flags {
 	CONFIG_SUPPORT_HW_CRYPTO,
 	DRIVER_SUPPORT_CONTROL_FILTERS,
 	DRIVER_SUPPORT_CONTROL_FILTER_PSPOLL,
+	DRIVER_SUPPORT_PRE_TBTT_INTERRUPT,
 
 	/*
 	 * Driver configuration
@@ -1068,6 +1069,7 @@ static inline void rt2x00debug_dump_frame(struct rt2x00_dev *rt2x00dev,
  * Interrupt context handlers.
  */
 void rt2x00lib_beacondone(struct rt2x00_dev *rt2x00dev);
+void rt2x00lib_pretbtt(struct rt2x00_dev *rt2x00dev);
 void rt2x00lib_txdone(struct queue_entry *entry,
 		      struct txdone_entry_desc *txdesc);
 void rt2x00lib_rxdone(struct rt2x00_dev *rt2x00dev,
diff --git a/drivers/net/wireless/rt2x00/rt2x00dev.c b/drivers/net/wireless/rt2x00/rt2x00dev.c
index 0ac8c49..9f5c98c 100644
--- a/drivers/net/wireless/rt2x00/rt2x00dev.c
+++ b/drivers/net/wireless/rt2x00/rt2x00dev.c
@@ -190,8 +190,8 @@ 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;
 
@@ -213,15 +213,33 @@ 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)
 {
-- 
1.6.4.2





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