zd1211rw: add TX watchdog and device resetting

When doing transfers at high speed for long time, tx queue can freeze. So add
tx watchdog. TX-watchdog checks for locked tx-urbs and reset hardware when
such is detected. Merely unlinking urb was not enough, device have to be
reseted. Hw settings are restored so that any open link will stay on after
reset.

Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 161 insertions, 0 deletions

diff --git a/drivers/net/wireless/zd1211rw/zd_usb.c b/drivers/net/wireless/zd1211rw/zd_usb.c
index 861dad192871..178d794be3fd 100644
--- a/drivers/net/wireless/zd1211rw/zd_usb.c
+++ b/drivers/net/wireless/zd1211rw/zd_usb.c
@@ -798,6 +798,7 @@ void zd_usb_disable_tx(struct zd_usb *usb)
 	usb_kill_anchored_urbs(&tx->submitted);
 
 	spin_lock_irqsave(&tx->lock, flags);
+	WARN_ON(!skb_queue_empty(&tx->submitted_skbs));
 	WARN_ON(tx->submitted_urbs != 0);
 	tx->submitted_urbs = 0;
 	spin_unlock_irqrestore(&tx->lock, flags);
@@ -895,6 +896,7 @@ static void tx_urb_complete(struct urb *urb)
 		goto resubmit;
 	}
 free_urb:
+	skb_unlink(skb, &usb->tx.submitted_skbs);
 	zd_mac_tx_to_dev(skb, urb->status);
 	usb_free_urb(urb);
 	tx_dec_submitted_urbs(usb);
@@ -924,6 +926,7 @@ resubmit:
 int zd_usb_tx(struct zd_usb *usb, struct sk_buff *skb)
 {
 	int r;
+	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 	struct usb_device *udev = zd_usb_to_usbdev(usb);
 	struct urb *urb;
 	struct zd_usb_tx *tx = &usb->tx;
@@ -942,10 +945,14 @@ int zd_usb_tx(struct zd_usb *usb, struct sk_buff *skb)
 	usb_fill_bulk_urb(urb, udev, usb_sndbulkpipe(udev, EP_DATA_OUT),
 		          skb->data, skb->len, tx_urb_complete, skb);
 
+	info->rate_driver_data[1] = (void *)jiffies;
+	skb_queue_tail(&tx->submitted_skbs, skb);
 	usb_anchor_urb(urb, &tx->submitted);
+
 	r = usb_submit_urb(urb, GFP_ATOMIC);
 	if (r) {
 		usb_unanchor_urb(urb);
+		skb_unlink(skb, &tx->submitted_skbs);
 		goto error;
 	}
 	tx_inc_submitted_urbs(usb);
@@ -956,6 +963,76 @@ out:
 	return r;
 }
 
+static bool zd_tx_timeout(struct zd_usb *usb)
+{
+	struct zd_usb_tx *tx = &usb->tx;
+	struct sk_buff_head *q = &tx->submitted_skbs;
+	struct sk_buff *skb, *skbnext;
+	struct ieee80211_tx_info *info;
+	unsigned long flags, trans_start;
+	bool have_timedout = false;
+
+	spin_lock_irqsave(&q->lock, flags);
+	skb_queue_walk_safe(q, skb, skbnext) {
+		info = IEEE80211_SKB_CB(skb);
+		trans_start = (unsigned long)info->rate_driver_data[1];
+
+		if (time_is_before_jiffies(trans_start + ZD_TX_TIMEOUT)) {
+			have_timedout = true;
+			break;
+		}
+	}
+	spin_unlock_irqrestore(&q->lock, flags);
+
+	return have_timedout;
+}
+
+static void zd_tx_watchdog_handler(struct work_struct *work)
+{
+	struct zd_usb *usb =
+		container_of(work, struct zd_usb, tx.watchdog_work.work);
+	struct zd_usb_tx *tx = &usb->tx;
+
+	if (!atomic_read(&tx->enabled) || !tx->watchdog_enabled)
+		goto out;
+	if (!zd_tx_timeout(usb))
+		goto out;
+
+	/* TX halted, try reset */
+	dev_warn(zd_usb_dev(usb), "TX-stall detected, reseting device...");
+
+	usb_queue_reset_device(usb->intf);
+
+	/* reset will stop this worker, don't rearm */
+	return;
+out:
+	queue_delayed_work(zd_workqueue, &tx->watchdog_work,
+			   ZD_TX_WATCHDOG_INTERVAL);
+}
+
+void zd_tx_watchdog_enable(struct zd_usb *usb)
+{
+	struct zd_usb_tx *tx = &usb->tx;
+
+	if (!tx->watchdog_enabled) {
+		dev_dbg_f(zd_usb_dev(usb), "\n");
+		queue_delayed_work(zd_workqueue, &tx->watchdog_work,
+				   ZD_TX_WATCHDOG_INTERVAL);
+		tx->watchdog_enabled = 1;
+	}
+}
+
+void zd_tx_watchdog_disable(struct zd_usb *usb)
+{
+	struct zd_usb_tx *tx = &usb->tx;
+
+	if (tx->watchdog_enabled) {
+		dev_dbg_f(zd_usb_dev(usb), "\n");
+		tx->watchdog_enabled = 0;
+		cancel_delayed_work_sync(&tx->watchdog_work);
+	}
+}
+
 static inline void init_usb_interrupt(struct zd_usb *usb)
 {
 	struct zd_usb_interrupt *intr = &usb->intr;
@@ -984,8 +1061,11 @@ static inline void init_usb_tx(struct zd_usb *usb)
 	spin_lock_init(&tx->lock);
 	atomic_set(&tx->enabled, 0);
 	tx->stopped = 0;
+	skb_queue_head_init(&tx->submitted_skbs);
 	init_usb_anchor(&tx->submitted);
 	tx->submitted_urbs = 0;
+	tx->watchdog_enabled = 0;
+	INIT_DELAYED_WORK(&tx->watchdog_work, zd_tx_watchdog_handler);
 }
 
 void zd_usb_init(struct zd_usb *usb, struct ieee80211_hw *hw,
@@ -1233,11 +1313,92 @@ static void disconnect(struct usb_interface *intf)
 	dev_dbg(&intf->dev, "disconnected\n");
 }
 
+static void zd_usb_resume(struct zd_usb *usb)
+{
+	struct zd_mac *mac = zd_usb_to_mac(usb);
+	int r;
+
+	dev_dbg_f(zd_usb_dev(usb), "\n");
+
+	r = zd_op_start(zd_usb_to_hw(usb));
+	if (r < 0) {
+		dev_warn(zd_usb_dev(usb), "Device resume failed "
+			 "with error code %d. Retrying...\n", r);
+		if (usb->was_running)
+			set_bit(ZD_DEVICE_RUNNING, &mac->flags);
+		usb_queue_reset_device(usb->intf);
+		return;
+	}
+
+	if (mac->type != NL80211_IFTYPE_UNSPECIFIED) {
+		r = zd_restore_settings(mac);
+		if (r < 0) {
+			dev_dbg(zd_usb_dev(usb),
+				"failed to restore settings, %d\n", r);
+			return;
+		}
+	}
+}
+
+static void zd_usb_stop(struct zd_usb *usb)
+{
+	dev_dbg_f(zd_usb_dev(usb), "\n");
+
+	zd_op_stop(zd_usb_to_hw(usb));
+
+	zd_usb_disable_tx(usb);
+	zd_usb_disable_rx(usb);
+	zd_usb_disable_int(usb);
+
+	usb->initialized = 0;
+}
+
+static int pre_reset(struct usb_interface *intf)
+{
+	struct ieee80211_hw *hw = usb_get_intfdata(intf);
+	struct zd_mac *mac;
+	struct zd_usb *usb;
+
+	if (!hw || intf->condition != USB_INTERFACE_BOUND)
+		return 0;
+
+	mac = zd_hw_mac(hw);
+	usb = &mac->chip.usb;
+
+	usb->was_running = test_bit(ZD_DEVICE_RUNNING, &mac->flags);
+
+	zd_usb_stop(usb);
+
+	mutex_lock(&mac->chip.mutex);
+	return 0;
+}
+
+static int post_reset(struct usb_interface *intf)
+{
+	struct ieee80211_hw *hw = usb_get_intfdata(intf);
+	struct zd_mac *mac;
+	struct zd_usb *usb;
+
+	if (!hw || intf->condition != USB_INTERFACE_BOUND)
+		return 0;
+
+	mac = zd_hw_mac(hw);
+	usb = &mac->chip.usb;
+
+	mutex_unlock(&mac->chip.mutex);
+
+	if (usb->was_running)
+		zd_usb_resume(usb);
+	return 0;
+}
+
 static struct usb_driver driver = {
 	.name		= KBUILD_MODNAME,
 	.id_table	= usb_ids,
 	.probe		= probe,
 	.disconnect	= disconnect,
+	.pre_reset	= pre_reset,
+	.post_reset	= post_reset,
 };
 
 struct workqueue_struct *zd_workqueue;