USB: WUSBCORE: clear RPIPE stall for control endpoints

When the HWA encounters a STALL on a control endpoint, it should clear the
RPIPE_STALL feature on the RPIPE before processing the next transfer
request.  Otherwise, all transfer requests on that endpoint after the
first STALL will fail because the RPIPE is still in the halted state.
This also removes the unneccessary call to spin_lock_irqsave for a nested
lock that was present in the first patch.

Signed-off-by: Thomas Pugliese <thomas.pugliese@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/wusbcore/wa-hc.h

@@ -91,6 +91,7 @@
 struct wusbhc;
 struct wahc;
 extern void wa_urb_enqueue_run(struct work_struct *ws);
+extern void wa_process_errored_transfers_run(struct work_struct *ws);
 
 /**
  * RPipe instance
@@ -190,8 +191,14 @@ struct wahc {
 
 	struct list_head xfer_list;
 	struct list_head xfer_delayed_list;
+	struct list_head xfer_errored_list;
+	/*
+	 * lock for the above xfer lists.  Can be taken while a xfer->lock is
+	 * held but not in the reverse order.
+	 */
 	spinlock_t xfer_list_lock;
-	struct work_struct xfer_work;
+	struct work_struct xfer_enqueue_work;
+	struct work_struct xfer_error_work;
 	atomic_t xfer_id_count;
 };
 
@@ -244,8 +251,10 @@ static inline void wa_init(struct wahc *wa)
 	edc_init(&wa->dti_edc);
 	INIT_LIST_HEAD(&wa->xfer_list);
 	INIT_LIST_HEAD(&wa->xfer_delayed_list);
+	INIT_LIST_HEAD(&wa->xfer_errored_list);
 	spin_lock_init(&wa->xfer_list_lock);
-	INIT_WORK(&wa->xfer_work, wa_urb_enqueue_run);
+	INIT_WORK(&wa->xfer_enqueue_work, wa_urb_enqueue_run);
+	INIT_WORK(&wa->xfer_error_work, wa_process_errored_transfers_run);
 	atomic_set(&wa->xfer_id_count, 1);
 }
 
@@ -269,6 +278,8 @@ static inline void rpipe_put(struct wa_rpipe *rpipe)
 
 }
 extern void rpipe_ep_disable(struct wahc *, struct usb_host_endpoint *);
+extern void rpipe_clear_feature_stalled(struct wahc *,
+			struct usb_host_endpoint *);
 extern int wa_rpipes_create(struct wahc *);
 extern void wa_rpipes_destroy(struct wahc *);
 static inline void rpipe_avail_dec(struct wa_rpipe *rpipe)

drivers/usb/wusbcore/wa-rpipe.c

@@ -527,3 +527,24 @@ void rpipe_ep_disable(struct wahc *wa, struct usb_host_endpoint *ep)
 	mutex_unlock(&wa->rpipe_mutex);
 }
 EXPORT_SYMBOL_GPL(rpipe_ep_disable);
+
+/* Clear the stalled status of an RPIPE. */
+void rpipe_clear_feature_stalled(struct wahc *wa, struct usb_host_endpoint *ep)
+{
+	struct wa_rpipe *rpipe;
+
+	mutex_lock(&wa->rpipe_mutex);
+	rpipe = ep->hcpriv;
+	if (rpipe != NULL) {
+		u16 index = le16_to_cpu(rpipe->descr.wRPipeIndex);
+
+		usb_control_msg(
+			wa->usb_dev, usb_rcvctrlpipe(wa->usb_dev, 0),
+			USB_REQ_CLEAR_FEATURE,
+			USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_RPIPE,
+			RPIPE_STALL, index, NULL, 0, 1000);
+	}
+	mutex_unlock(&wa->rpipe_mutex);
+}
+EXPORT_SYMBOL_GPL(rpipe_clear_feature_stalled);
+

drivers/usb/wusbcore/wa-xfer.c

@@ -1100,7 +1100,7 @@ error_xfer_submit:
  */
 void wa_urb_enqueue_run(struct work_struct *ws)
 {
-	struct wahc *wa = container_of(ws, struct wahc, xfer_work);
+	struct wahc *wa = container_of(ws, struct wahc, xfer_enqueue_work);
 	struct wa_xfer *xfer, *next;
 	struct urb *urb;
 	LIST_HEAD(tmp_list);
@@ -1125,6 +1125,49 @@ void wa_urb_enqueue_run(struct work_struct *ws)
 }
 EXPORT_SYMBOL_GPL(wa_urb_enqueue_run);
 
+/*
+ * Process the errored transfers on the Wire Adapter outside of interrupt.
+ */
+void wa_process_errored_transfers_run(struct work_struct *ws)
+{
+	struct wahc *wa = container_of(ws, struct wahc, xfer_error_work);
+	struct wa_xfer *xfer, *next;
+	LIST_HEAD(tmp_list);
+
+	pr_info("%s: Run delayed STALL processing.\n", __func__);
+
+	/* Create a copy of the wa->xfer_errored_list while holding the lock */
+	spin_lock_irq(&wa->xfer_list_lock);
+	list_cut_position(&tmp_list, &wa->xfer_errored_list,
+			wa->xfer_errored_list.prev);
+	spin_unlock_irq(&wa->xfer_list_lock);
+
+	/*
+	 * run rpipe_clear_feature_stalled from temp list without list lock
+	 * held.
+	 */
+	list_for_each_entry_safe(xfer, next, &tmp_list, list_node) {
+		struct usb_host_endpoint *ep;
+		unsigned long flags;
+		struct wa_rpipe *rpipe;
+
+		spin_lock_irqsave(&xfer->lock, flags);
+		ep = xfer->ep;
+		rpipe = ep->hcpriv;
+		spin_unlock_irqrestore(&xfer->lock, flags);
+
+		/* clear RPIPE feature stalled without holding a lock. */
+		rpipe_clear_feature_stalled(wa, ep);
+
+		/* complete the xfer. This removes it from the tmp list. */
+		wa_xfer_completion(xfer);
+
+		/* check for work. */
+		wa_xfer_delayed_run(rpipe);
+	}
+}
+EXPORT_SYMBOL_GPL(wa_process_errored_transfers_run);
+
 /*
  * Submit a transfer to the Wire Adapter in a delayed way
  *
@@ -1180,7 +1223,7 @@ int wa_urb_enqueue(struct wahc *wa, struct usb_host_endpoint *ep,
 		spin_lock_irqsave(&wa->xfer_list_lock, my_flags);
 		list_add_tail(&xfer->list_node, &wa->xfer_delayed_list);
 		spin_unlock_irqrestore(&wa->xfer_list_lock, my_flags);
-		queue_work(wusbd, &wa->xfer_work);
+		queue_work(wusbd, &wa->xfer_enqueue_work);
 	} else {
 		wa_urb_enqueue_b(xfer);
 	}
@@ -1222,7 +1265,8 @@ int wa_urb_dequeue(struct wahc *wa, struct urb *urb)
 
 	xfer = urb->hcpriv;
 	if (xfer == NULL) {
-		/* NOthing setup yet enqueue will see urb->status !=
+		/*
+		 * Nothing setup yet enqueue will see urb->status !=
 		 * -EINPROGRESS (by hcd layer) and bail out with
 		 * error, no need to do completion
 		 */
@@ -1360,7 +1404,7 @@ static int wa_xfer_status_to_errno(u8 status)
  *
  * inbound transfers: need to schedule a DTI read
  *
- * FIXME: this functio needs to be broken up in parts
+ * FIXME: this function needs to be broken up in parts
  */
 static void wa_xfer_result_chew(struct wahc *wa, struct wa_xfer *xfer)
 {
@@ -1482,17 +1526,37 @@ error_submit_buf_in:
 	seg->result = result;
 	kfree(wa->buf_in_urb->sg);
 error_sg_alloc:
+	__wa_xfer_abort(xfer);
 error_complete:
 	seg->status = WA_SEG_ERROR;
 	xfer->segs_done++;
 	rpipe_ready = rpipe_avail_inc(rpipe);
-	__wa_xfer_abort(xfer);
 	done = __wa_xfer_is_done(xfer);
-	spin_unlock_irqrestore(&xfer->lock, flags);
-	if (done)
-		wa_xfer_completion(xfer);
-	if (rpipe_ready)
-		wa_xfer_delayed_run(rpipe);
+	/*
+	 * queue work item to clear STALL for control endpoints.
+	 * Otherwise, let endpoint_reset take care of it.
+	 */
+	if (((usb_status & 0x3f) == WA_XFER_STATUS_HALTED) &&
+		usb_endpoint_xfer_control(&xfer->ep->desc) &&
+		done) {
+
+		dev_info(dev, "Control EP stall.  Queue delayed work.\n");
+		spin_lock_irq(&wa->xfer_list_lock);
+		/* remove xfer from xfer_list. */
+		list_del(&xfer->list_node);
+		/* add xfer to xfer_errored_list. */
+		list_add_tail(&xfer->list_node, &wa->xfer_errored_list);
+		spin_unlock_irq(&wa->xfer_list_lock);
+		spin_unlock_irqrestore(&xfer->lock, flags);
+		queue_work(wusbd, &wa->xfer_error_work);
+	} else {
+		spin_unlock_irqrestore(&xfer->lock, flags);
+		if (done)
+			wa_xfer_completion(xfer);
+		if (rpipe_ready)
+			wa_xfer_delayed_run(rpipe);
+	}
+
 	return;
 
 error_bad_seg:

include/linux/usb/wusb-wa.h

@@ -66,6 +66,7 @@ enum {
 	WA_ENABLE = 0x01,
 	WA_RESET = 0x02,
 	RPIPE_PAUSE = 0x1,
+	RPIPE_STALL = 0x2,
 };
 
 /* Responses from Get Status request ([WUSB] section 8.3.1.6) */