USB: xhci: Refactor code to free or cache endpoint rings.

Refactor out the code to cache or free endpoint rings from recently
dropped or disabled endpoints.  This code will be used by a new function
to reset a device and disable all endpoints except control endpoint 0.

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 25 insertions, 0 deletions

diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index bffcef7a5545..1f1f8a0f2e66 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -198,6 +198,31 @@ fail:
         return 0;
 }
 
+void xhci_free_or_cache_endpoint_ring(struct xhci_hcd *xhci,
+                struct xhci_virt_device *virt_dev,
+                unsigned int ep_index)
+{
+        int rings_cached;
+
+        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[ep_index].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[ep_index].ring);
+                xhci_dbg(xhci, "Ring cache full (%d rings), "
+                                "freeing ring\n",
+                                virt_dev->num_rings_cached);
+        }
+        virt_dev->eps[ep_index].ring = NULL;
+}
+
 /* Zero an endpoint ring (except for link TRBs) and move the enqueue and dequeue
  * pointers to the beginning of the ring.
  */