rt2x00: Add watchdog functions for HW queue

Add watchdog functions for managing the Queues inside the hardware.
Normally the driver doesn't have much to do with these queues
directly, but the Ralink drivers did implement watchdog functions
for these. These watchdog functions are not triggered that often,
compared to the other watchdog functions, but I have at least
seen them trigger once or twice during a long stresstest run.

v2: Add extra documentation for register fields

Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Acked-by: Gertjan van Wingerde <gwingerde@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rt2x00/rt2800.h

@@ -412,10 +412,22 @@
 #define BCN_OFFSET1_BCN7		FIELD32(0xff000000)
 
 /*
- * PBF registers
- * Most are for debug. Driver doesn't touch PBF register.
+ * TXRXQ_PCNT: PBF register
+ * PCNT_TX0Q: Page count for TX hardware queue 0
+ * PCNT_TX1Q: Page count for TX hardware queue 1
+ * PCNT_TX2Q: Page count for TX hardware queue 2
+ * PCNT_RX0Q: Page count for RX hardware queue
  */
 #define TXRXQ_PCNT			0x0438
+#define TXRXQ_PCNT_TX0Q			FIELD32(0x000000ff)
+#define TXRXQ_PCNT_TX1Q			FIELD32(0x0000ff00)
+#define TXRXQ_PCNT_TX2Q			FIELD32(0x00ff0000)
+#define TXRXQ_PCNT_RX0Q			FIELD32(0xff000000)
+
+/*
+ * PBF register
+ * Debug. Driver doesn't touch PBF register.
+ */
 #define PBF_DBG				0x043c
 
 /*

drivers/net/wireless/rt2x00/rt2800usb.c

@@ -242,6 +242,49 @@ static int rt2800usb_set_device_state(struct rt2x00_dev *rt2x00dev,
 	return retval;
 }
 
+/*
+ * Watchdog handlers
+ */
+static void rt2800usb_watchdog(struct rt2x00_dev *rt2x00dev)
+{
+	unsigned int i;
+	u32 reg;
+
+	rt2800_register_read(rt2x00dev, TXRXQ_PCNT, &reg);
+	if (rt2x00_get_field32(reg, TXRXQ_PCNT_TX0Q)) {
+		WARNING(rt2x00dev, "TX HW queue 0 timed out,"
+			" invoke forced kick");
+
+		rt2800_register_write(rt2x00dev, PBF_CFG, 0xf40012);
+
+		for (i = 0; i < 10; i++) {
+			udelay(10);
+			if (!rt2x00_get_field32(reg, TXRXQ_PCNT_TX0Q))
+				break;
+		}
+
+		rt2800_register_write(rt2x00dev, PBF_CFG, 0xf40006);
+	}
+
+	rt2800_register_read(rt2x00dev, TXRXQ_PCNT, &reg);
+	if (rt2x00_get_field32(reg, TXRXQ_PCNT_TX1Q)) {
+		WARNING(rt2x00dev, "TX HW queue 1 timed out,"
+			" invoke forced kick");
+
+		rt2800_register_write(rt2x00dev, PBF_CFG, 0xf4000a);
+
+		for (i = 0; i < 10; i++) {
+			udelay(10);
+			if (!rt2x00_get_field32(reg, TXRXQ_PCNT_TX1Q))
+				break;
+		}
+
+		rt2800_register_write(rt2x00dev, PBF_CFG, 0xf40006);
+	}
+
+	rt2x00usb_watchdog(rt2x00dev);
+}
+
 /*
  * TX descriptor initialization
  */
@@ -534,7 +577,7 @@ static const struct rt2x00lib_ops rt2800usb_rt2x00_ops = {
 	.link_stats		= rt2800_link_stats,
 	.reset_tuner		= rt2800_reset_tuner,
 	.link_tuner		= rt2800_link_tuner,
-	.watchdog		= rt2x00usb_watchdog,
+	.watchdog		= rt2800usb_watchdog,
 	.write_tx_desc		= rt2800usb_write_tx_desc,
 	.write_tx_data		= rt2800_write_tx_data,
 	.write_beacon		= rt2800_write_beacon,