rt2x00: Initialize AMPDU_BA_WINSIZE register

Since we're not using the AMPDU_BA_WINSIZE register to force the BlockAck
window size (we specify it in every TXWI) we should initialize it to 0.
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>

drivers/net/wireless/rt2x00/rt2800.h

@@ -638,6 +638,18 @@
 #define LED_CFG_Y_LED_MODE		FIELD32(0x30000000)
 #define LED_CFG_LED_POLAR		FIELD32(0x40000000)
 
+/*
+ * AMPDU_BA_WINSIZE: Force BlockAck window size
+ * FORCE_WINSIZE_ENABLE:
+ *   0: Disable forcing of BlockAck window size
+ *   1: Enable forcing of BlockAck window size, overwrites values BlockAck
+ *      window size values in the TXWI
+ * FORCE_WINSIZE: BlockAck window size
+ */
+#define AMPDU_BA_WINSIZE		0x1040
+#define AMPDU_BA_WINSIZE_FORCE_WINSIZE_ENABLE FIELD32(0x00000020)
+#define AMPDU_BA_WINSIZE_FORCE_WINSIZE	FIELD32(0x0000001f)
+
 /*
  * XIFS_TIME_CFG: MAC timing
  * CCKM_SIFS_TIME: unit 1us. Applied after CCK RX/TX

drivers/net/wireless/rt2x00/rt2800lib.c

@@ -2052,6 +2052,14 @@ static int rt2800_init_registers(struct rt2x00_dev *rt2x00dev)
 	rt2x00_set_field32(&reg, LG_FBK_CFG0_CCKMCS3FBK, 2);
 	rt2800_register_write(rt2x00dev, LG_FBK_CFG1, reg);
 
+	/*
+	 * Do not force the BA window size, we use the TXWI to set it
+	 */
+	rt2800_register_read(rt2x00dev, AMPDU_BA_WINSIZE, &reg);
+	rt2x00_set_field32(&reg, AMPDU_BA_WINSIZE_FORCE_WINSIZE_ENABLE, 0);
+	rt2x00_set_field32(&reg, AMPDU_BA_WINSIZE_FORCE_WINSIZE, 0);
+	rt2800_register_write(rt2x00dev, AMPDU_BA_WINSIZE, reg);
+
 	/*
 	 * We must clear the error counters.
 	 * These registers are cleared on read,