---

yaml
---
r: 174992
b: refs/heads/master
c: 74f9fe2
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 3342ecda3ffb059f2ffd765a71d9579f0aa036eb
+refs/heads/master: 74f9fe21e0440066eb337b9f644238cb3050b91c

trunk/drivers/usb/host/xhci-hcd.c

@@ -1262,13 +1262,35 @@ int xhci_check_bandwidth(struct usb_hcd *hcd, struct usb_device *udev)
 			LAST_CTX_TO_EP_NUM(slot_ctx->dev_info));
 
 	xhci_zero_in_ctx(xhci, virt_dev);
-	/* Free any old rings */
+	/* Install new rings and free or cache any old rings */
 	for (i = 1; i < 31; ++i) {
-		if (virt_dev->eps[i].new_ring) {
-			xhci_ring_free(xhci, virt_dev->eps[i].ring);
-			virt_dev->eps[i].ring = virt_dev->eps[i].new_ring;
-			virt_dev->eps[i].new_ring = NULL;
+		int rings_cached;
+
+		if (!virt_dev->eps[i].new_ring)
+			continue;
+		/* Only cache or free the old ring if it exists.
+		 * It may not if this is the first add of an endpoint.
+		 */
+		if (virt_dev->eps[i].ring) {
+			rings_cached = virt_dev->num_rings_cached;
+			if (rings_cached < XHCI_MAX_RINGS_CACHED) {
+				virt_dev->num_rings_cached++;
+				rings_cached = virt_dev->num_rings_cached;
+				virt_dev->ring_cache[rings_cached] =
+					virt_dev->eps[i].ring;
+				xhci_dbg(xhci, "Cached old ring, "
+						"%d ring%s cached\n",
+						rings_cached,
+						(rings_cached > 1) ? "s" : "");
+			} else {
+				xhci_ring_free(xhci, virt_dev->eps[i].ring);
+				xhci_dbg(xhci, "Ring cache full (%d rings), "
+						"freeing ring\n",
+						virt_dev->num_rings_cached);
+			}
 		}
+		virt_dev->eps[i].ring = virt_dev->eps[i].new_ring;
+		virt_dev->eps[i].new_ring = NULL;
 	}
 
 	return ret;

trunk/drivers/usb/host/xhci-mem.c

@@ -125,6 +125,23 @@ void xhci_ring_free(struct xhci_hcd *xhci, struct xhci_ring *ring)
 	kfree(ring);
 }
 
+static void xhci_initialize_ring_info(struct xhci_ring *ring)
+{
+	/* The ring is empty, so the enqueue pointer == dequeue pointer */
+	ring->enqueue = ring->first_seg->trbs;
+	ring->enq_seg = ring->first_seg;
+	ring->dequeue = ring->enqueue;
+	ring->deq_seg = ring->first_seg;
+	/* The ring is initialized to 0. The producer must write 1 to the cycle
+	 * bit to handover ownership of the TRB, so PCS = 1.  The consumer must
+	 * compare CCS to the cycle bit to check ownership, so CCS = 1.
+	 */
+	ring->cycle_state = 1;
+	/* Not necessary for new rings, but needed for re-initialized rings */
+	ring->enq_updates = 0;
+	ring->deq_updates = 0;
+}
+
 /**
  * Create a new ring with zero or more segments.
  *
@@ -173,24 +190,35 @@ static struct xhci_ring *xhci_ring_alloc(struct xhci_hcd *xhci,
 				" segment %p (virtual), 0x%llx (DMA)\n",
 				prev, (unsigned long long)prev->dma);
 	}
-	/* The ring is empty, so the enqueue pointer == dequeue pointer */
-	ring->enqueue = ring->first_seg->trbs;
-	ring->enq_seg = ring->first_seg;
-	ring->dequeue = ring->enqueue;
-	ring->deq_seg = ring->first_seg;
-	/* The ring is initialized to 0. The producer must write 1 to the cycle
-	 * bit to handover ownership of the TRB, so PCS = 1.  The consumer must
-	 * compare CCS to the cycle bit to check ownership, so CCS = 1.
-	 */
-	ring->cycle_state = 1;
-
+	xhci_initialize_ring_info(ring);
 	return ring;
 
 fail:
 	xhci_ring_free(xhci, ring);
 	return 0;
 }
 
+/* Zero an endpoint ring (except for link TRBs) and move the enqueue and dequeue
+ * pointers to the beginning of the ring.
+ */
+static void xhci_reinit_cached_ring(struct xhci_hcd *xhci,
+		struct xhci_ring *ring)
+{
+	struct xhci_segment	*seg = ring->first_seg;
+	do {
+		memset(seg->trbs, 0,
+				sizeof(union xhci_trb)*TRBS_PER_SEGMENT);
+		/* All endpoint rings have link TRBs */
+		xhci_link_segments(xhci, seg, seg->next, 1);
+		seg = seg->next;
+	} while (seg != ring->first_seg);
+	xhci_initialize_ring_info(ring);
+	/* td list should be empty since all URBs have been cancelled,
+	 * but just in case...
+	 */
+	INIT_LIST_HEAD(&ring->td_list);
+}
+
 #define CTX_SIZE(_hcc) (HCC_64BYTE_CONTEXT(_hcc) ? 64 : 32)
 
 struct xhci_container_ctx *xhci_alloc_container_ctx(struct xhci_hcd *xhci,
@@ -276,6 +304,12 @@ void xhci_free_virt_device(struct xhci_hcd *xhci, int slot_id)
 		if (dev->eps[i].ring)
 			xhci_ring_free(xhci, dev->eps[i].ring);
 
+	if (dev->ring_cache) {
+		for (i = 0; i < dev->num_rings_cached; i++)
+			xhci_ring_free(xhci, dev->ring_cache[i]);
+		kfree(dev->ring_cache);
+	}
+
 	if (dev->in_ctx)
 		xhci_free_container_ctx(xhci, dev->in_ctx);
 	if (dev->out_ctx)
@@ -329,6 +363,14 @@ int xhci_alloc_virt_device(struct xhci_hcd *xhci, int slot_id,
 	if (!dev->eps[0].ring)
 		goto fail;
 
+	/* Allocate pointers to the ring cache */
+	dev->ring_cache = kzalloc(
+			sizeof(struct xhci_ring *)*XHCI_MAX_RINGS_CACHED,
+			flags);
+	if (!dev->ring_cache)
+		goto fail;
+	dev->num_rings_cached = 0;
+
 	init_completion(&dev->cmd_completion);
 	INIT_LIST_HEAD(&dev->cmd_list);
 
@@ -555,8 +597,16 @@ int xhci_endpoint_init(struct xhci_hcd *xhci,
 	/* Set up the endpoint ring */
 	virt_dev->eps[ep_index].new_ring =
 		xhci_ring_alloc(xhci, 1, true, mem_flags);
-	if (!virt_dev->eps[ep_index].new_ring)
-		return -ENOMEM;
+	if (!virt_dev->eps[ep_index].new_ring) {
+		/* Attempt to use the ring cache */
+		if (virt_dev->num_rings_cached == 0)
+			return -ENOMEM;
+		virt_dev->eps[ep_index].new_ring =
+			virt_dev->ring_cache[virt_dev->num_rings_cached];
+		virt_dev->ring_cache[virt_dev->num_rings_cached] = NULL;
+		virt_dev->num_rings_cached--;
+		xhci_reinit_cached_ring(xhci, virt_dev->eps[ep_index].new_ring);
+	}
 	ep_ring = virt_dev->eps[ep_index].new_ring;
 	ep_ctx->deq = ep_ring->first_seg->dma | ep_ring->cycle_state;
 

trunk/drivers/usb/host/xhci.h

@@ -677,6 +677,10 @@ struct xhci_virt_device {
 	struct xhci_container_ctx       *out_ctx;
 	/* Used for addressing devices and configuration changes */
 	struct xhci_container_ctx       *in_ctx;
+	/* Rings saved to ensure old alt settings can be re-instated */
+	struct xhci_ring		**ring_cache;
+	int				num_rings_cached;
+#define	XHCI_MAX_RINGS_CACHED	31
 	struct xhci_virt_ep		eps[31];
 	struct completion		cmd_completion;
 	/* Status of the last command issued for this device */