1 files changed, 24 insertions, 8 deletions

diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index 36cbe2226a44..383fc857491c 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -1126,26 +1126,42 @@ static unsigned int xhci_parse_exponent_interval(struct usb_device *udev,
 }
 
 /*
- * Convert bInterval expressed in frames (in 1-255 range) to exponent of
+ * Convert bInterval expressed in microframes (in 1-255 range) to exponent of
  * microframes, rounded down to nearest power of 2.
  */
-static unsigned int xhci_parse_frame_interval(struct usb_device *udev,
-                struct usb_host_endpoint *ep)
+static unsigned int xhci_microframes_to_exponent(struct usb_device *udev,
+                struct usb_host_endpoint *ep, unsigned int desc_interval,
+                unsigned int min_exponent, unsigned int max_exponent)
 {
         unsigned int interval;
 
-        interval = fls(8 * ep->desc.bInterval) - 1;
-        interval = clamp_val(interval, 3, 10);
-        if ((1 << interval) != 8 * ep->desc.bInterval)
+        interval = fls(desc_interval) - 1;
+        interval = clamp_val(interval, min_exponent, max_exponent);
+        if ((1 << interval) != desc_interval)
                 dev_warn(&udev->dev,
                          "ep %#x - rounding interval to %d microframes, ep desc says %d microframes\n",
                          ep->desc.bEndpointAddress,
                          1 << interval,
-                         8 * ep->desc.bInterval);
+                         desc_interval);
 
         return interval;
 }
 
+static unsigned int xhci_parse_microframe_interval(struct usb_device *udev,
+                struct usb_host_endpoint *ep)
+{
+        return xhci_microframes_to_exponent(udev, ep,
+                        ep->desc.bInterval, 0, 15);
+}
+
+
+static unsigned int xhci_parse_frame_interval(struct usb_device *udev,
+                struct usb_host_endpoint *ep)
+{
+        return xhci_microframes_to_exponent(udev, ep,
+                        ep->desc.bInterval * 8, 3, 10);
+}
+
 /* Return the polling or NAK interval.
  *
  * The polling interval is expressed in "microframes".  If xHCI's Interval field
@@ -1164,7 +1180,7 @@ static unsigned int xhci_get_endpoint_interval(struct usb_device *udev,
                 /* Max NAK rate */
                 if (usb_endpoint_xfer_control(&ep->desc) ||
                     usb_endpoint_xfer_bulk(&ep->desc)) {
-                        interval = ep->desc.bInterval;
+                        interval = xhci_parse_microframe_interval(udev, ep);
                         break;
                 }
                 /* Fall through - SS and HS isoc/int have same decoding */