1 files changed, 69 insertions, 0 deletions

diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index 6a05e693445..3aaee2811f0 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -1814,6 +1814,75 @@ void usb_hcd_reset_endpoint(struct usb_device *udev,
         }
 }
 
+/**
+ * usb_alloc_streams - allocate bulk endpoint stream IDs.
+ * @interface:          alternate setting that includes all endpoints.
+ * @eps:                array of endpoints that need streams.
+ * @num_eps:            number of endpoints in the array.
+ * @num_streams:        number of streams to allocate.
+ * @mem_flags:          flags hcd should use to allocate memory.
+ *
+ * Sets up a group of bulk endpoints to have num_streams stream IDs available.
+ * Drivers may queue multiple transfers to different stream IDs, which may
+ * complete in a different order than they were queued.
+ */
+int usb_alloc_streams(struct usb_interface *interface,
+                struct usb_host_endpoint **eps, unsigned int num_eps,
+                unsigned int num_streams, gfp_t mem_flags)
+{
+        struct usb_hcd *hcd;
+        struct usb_device *dev;
+        int i;
+
+        dev = interface_to_usbdev(interface);
+        hcd = bus_to_hcd(dev->bus);
+        if (!hcd->driver->alloc_streams || !hcd->driver->free_streams)
+                return -EINVAL;
+        if (dev->speed != USB_SPEED_SUPER)
+                return -EINVAL;
+
+        /* Streams only apply to bulk endpoints. */
+        for (i = 0; i < num_eps; i++)
+                if (!usb_endpoint_xfer_bulk(&eps[i]->desc))
+                        return -EINVAL;
+
+        return hcd->driver->alloc_streams(hcd, dev, eps, num_eps,
+                        num_streams, mem_flags);
+}
+EXPORT_SYMBOL_GPL(usb_alloc_streams);
+
+/**
+ * usb_free_streams - free bulk endpoint stream IDs.
+ * @interface:  alternate setting that includes all endpoints.
+ * @eps:        array of endpoints to remove streams from.
+ * @num_eps:    number of endpoints in the array.
+ * @mem_flags:  flags hcd should use to allocate memory.
+ *
+ * Reverts a group of bulk endpoints back to not using stream IDs.
+ * Can fail if we are given bad arguments, or HCD is broken.
+ */
+void usb_free_streams(struct usb_interface *interface,
+                struct usb_host_endpoint **eps, unsigned int num_eps,
+                gfp_t mem_flags)
+{
+        struct usb_hcd *hcd;
+        struct usb_device *dev;
+        int i;
+
+        dev = interface_to_usbdev(interface);
+        hcd = bus_to_hcd(dev->bus);
+        if (dev->speed != USB_SPEED_SUPER)
+                return;
+
+        /* Streams only apply to bulk endpoints. */
+        for (i = 0; i < num_eps; i++)
+                if (!usb_endpoint_xfer_bulk(&eps[i]->desc))
+                        return;
+
+        hcd->driver->free_streams(hcd, dev, eps, num_eps, mem_flags);
+}
+EXPORT_SYMBOL_GPL(usb_free_streams);
+
 /* Protect against drivers that try to unlink URBs after the device
  * is gone, by waiting until all unlinks for @udev are finished.
  * Since we don't currently track URBs by device, simply wait until