usb: musb: fix BULK request on different available endpoints

Fixes co-working issue of usb serial device with usb/net devices while
oter endpoints are free and can be used.This patch implements the policy
that if endpoint resources are available then different BULK request goes
to different endpoint otherwise they are multiplexed to one reserved
endpoint as currently done.

Switch statement case is reordered in musb_giveback() to take care of
bulk request both in multiplex scenario and otherwise.

NAK limit scheme has to be added for multiplexed BULK request scenario
to avoid endpoint starvation due to usb/net devices.
Signed-off-by: Ajay Kumar Gupta <ajay.gupta@ti.com>
Signed-off-by: Felipe Balbi <felipe.balbi@nokia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/musb/musb_host.c

@@ -378,28 +378,30 @@ musb_giveback(struct musb_qh *qh, struct urb *urb, int status)
 
 		switch (qh->type) {
 
-		case USB_ENDPOINT_XFER_ISOC:
-		case USB_ENDPOINT_XFER_INT:
-			/* this is where periodic bandwidth should be
-			 * de-allocated if it's tracked and allocated;
-			 * and where we'd update the schedule tree...
-			 */
-			musb->periodic[ep->epnum] = NULL;
-			kfree(qh);
-			qh = NULL;
-			break;
-
 		case USB_ENDPOINT_XFER_CONTROL:
 		case USB_ENDPOINT_XFER_BULK:
 			/* fifo policy for these lists, except that NAKing
 			 * should rotate a qh to the end (for fairness).
 			 */
+			if (qh->mux == 1) {
 				head = qh->ring.prev;
 				list_del(&qh->ring);
 				kfree(qh);
 				qh = first_qh(head);
 				break;
 			}
+
+		case USB_ENDPOINT_XFER_ISOC:
+		case USB_ENDPOINT_XFER_INT:
+			/* this is where periodic bandwidth should be
+			 * de-allocated if it's tracked and allocated;
+			 * and where we'd update the schedule tree...
+			 */
+			musb->periodic[ep->epnum] = NULL;
+			kfree(qh);
+			qh = NULL;
+			break;
+		}
 	}
 	return qh;
 }
@@ -1708,22 +1710,9 @@ static int musb_schedule(
 	struct list_head	*head = NULL;
 
 	/* use fixed hardware for control and bulk */
-	switch (qh->type) {
-	case USB_ENDPOINT_XFER_CONTROL:
+	if (qh->type == USB_ENDPOINT_XFER_CONTROL) {
 		head = &musb->control;
 		hw_ep = musb->control_ep;
-		break;
-	case USB_ENDPOINT_XFER_BULK:
-		hw_ep = musb->bulk_ep;
-		if (is_in)
-			head = &musb->in_bulk;
-		else
-			head = &musb->out_bulk;
-		break;
-	}
-	if (head) {
-		idle = list_empty(head);
-		list_add_tail(&qh->ring, head);
 		goto success;
 	}
 
@@ -1762,19 +1751,34 @@ static int musb_schedule(
 		else
 			diff = hw_ep->max_packet_sz_tx - qh->maxpacket;
 
-		if (diff > 0 && best_diff > diff) {
+		if (diff >= 0 && best_diff > diff) {
 			best_diff = diff;
 			best_end = epnum;
 		}
 	}
-	if (best_end < 0)
+	/* use bulk reserved ep1 if no other ep is free */
+	if (best_end > 0 && qh->type == USB_ENDPOINT_XFER_BULK) {
+		hw_ep = musb->bulk_ep;
+		if (is_in)
+			head = &musb->in_bulk;
+		else
+			head = &musb->out_bulk;
+		goto success;
+	} else if (best_end < 0) {
 		return -ENOSPC;
+	}
 
 	idle = 1;
+	qh->mux = 0;
 	hw_ep = musb->endpoints + best_end;
 	musb->periodic[best_end] = qh;
 	DBG(4, "qh %p periodic slot %d\n", qh, best_end);
 success:
+	if (head) {
+		idle = list_empty(head);
+		list_add_tail(&qh->ring, head);
+		qh->mux = 1;
+	}
 	qh->hw_ep = hw_ep;
 	qh->hep->hcpriv = qh;
 	if (idle)
@@ -2052,11 +2056,13 @@ static int musb_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
 			sched = &musb->control;
 			break;
 		case USB_ENDPOINT_XFER_BULK:
+			if (qh->mux == 1) {
 				if (usb_pipein(urb->pipe))
 					sched = &musb->in_bulk;
 				else
 					sched = &musb->out_bulk;
 				break;
+			}
 		default:
 			/* REVISIT when we get a schedule tree, periodic
 			 * transfers won't always be at the head of a
@@ -2104,11 +2110,13 @@ musb_h_disable(struct usb_hcd *hcd, struct usb_host_endpoint *hep)
 		sched = &musb->control;
 		break;
 	case USB_ENDPOINT_XFER_BULK:
+		if (qh->mux == 1) {
 			if (is_in)
 				sched = &musb->in_bulk;
 			else
 				sched = &musb->out_bulk;
 			break;
+		}
 	default:
 		/* REVISIT when we get a schedule tree, periodic transfers
 		 * won't always be at the head of a singleton queue...

drivers/usb/musb/musb_host.h

@@ -53,6 +53,7 @@ struct musb_qh {
 
 	struct list_head	ring;		/* of musb_qh */
 	/* struct musb_qh		*next; */	/* for periodic tree */
+	u8			mux;		/* qh multiplexed to hw_ep */
 
 	unsigned		offset;		/* in urb->transfer_buffer */
 	unsigned		segsize;	/* current xfer fragment */