rt2800: do not enable watchdog by default

Make watchdog disabled by default and add module parameter to enable it.

User will have to create file in /etc/modprobe.d/ with

options rt2800lib watchdog=1

to enable the watchdog or load "rt2800lib watchdog=1" module manually
before loading rt2800{soc,pci,usb} module.
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/ralink/rt2x00/rt2800lib.c

@@ -30,6 +30,10 @@
 #include "rt2800lib.h"
 #include "rt2800.h"
 
+static bool modparam_watchdog;
+module_param_named(watchdog, modparam_watchdog, bool, S_IRUGO);
+MODULE_PARM_DESC(watchdog, "Enable watchdog to detect tx/rx hangs and reset hardware if detected");
+
 /*
  * Register access.
  * All access to the CSR registers will go through the methods
@@ -10286,8 +10290,12 @@ int rt2800_probe_hw(struct rt2x00_dev *rt2x00dev)
 		__set_bit(REQUIRE_TASKLET_CONTEXT, &rt2x00dev->cap_flags);
 	}
 
-	__set_bit(CAPABILITY_RESTART_HW, &rt2x00dev->cap_flags);
-	rt2x00dev->link.watchdog_interval = msecs_to_jiffies(100);
+	if (modparam_watchdog) {
+		__set_bit(CAPABILITY_RESTART_HW, &rt2x00dev->cap_flags);
+		rt2x00dev->link.watchdog_interval = msecs_to_jiffies(100);
+	} else {
+		rt2x00dev->link.watchdog_disabled = true;
+	}
 
 	/*
 	 * Set the rssi offset.

drivers/net/wireless/ralink/rt2x00/rt2x00.h

@@ -326,6 +326,7 @@ struct link {
 	 */
 	struct delayed_work watchdog_work;
 	unsigned int watchdog_interval;
+	bool watchdog_disabled;
 
 	/*
 	 * Work structure for scheduling periodic AGC adjustments.

drivers/net/wireless/ralink/rt2x00/rt2x00link.c

@@ -384,7 +384,7 @@ void rt2x00link_start_watchdog(struct rt2x00_dev *rt2x00dev)
 	struct link *link = &rt2x00dev->link;
 
 	if (test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags) &&
-	    rt2x00dev->ops->lib->watchdog)
+	    rt2x00dev->ops->lib->watchdog && !link->watchdog_disabled)
 		ieee80211_queue_delayed_work(rt2x00dev->hw,
 					     &link->watchdog_work,
 					     link->watchdog_interval);