USB: add direction bit to urb->transfer_flags

This patch (as945) adds a bit to urb->transfer_flags for recording the
direction of the URB.  The bit is set/cleared automatically in
usb_submit_urb() so drivers don't have to worry about it (although as
a result, it isn't valid until the URB has been submitted).  Inline
routines are added for easily checking an URB's direction.  They
replace calls to usb_pipein in the DMA-mapping parts of hcd.c.

For non-control endpoints, the direction is determined directly from
the endpoint descriptor.  However control endpoints are
bi-directional; for them the direction is determined from the
bRequestType byte and the wLength value in the setup packet.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 30 insertions, 0 deletions

diff --git a/include/linux/usb.h b/include/linux/usb.h
index 818a1b4f737a..9d08f5a5ba76 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -1021,6 +1021,8 @@ extern int usb_disabled(void);
 
 /*
  * urb->transfer_flags:
+ *
+ * Note: URB_DIR_IN/OUT is automatically set in usb_submit_urb().
  */
 #define URB_SHORT_NOT_OK        0x0001  /* report short reads as errors */
 #define URB_ISO_ASAP            0x0002  /* iso-only, urb->start_frame
@@ -1033,6 +1035,10 @@ extern int usb_disabled(void);
                                          * needed */
 #define URB_FREE_BUFFER         0x0100  /* Free transfer buffer with the URB */
 
+#define URB_DIR_IN              0x0200  /* Transfer from device to host */
+#define URB_DIR_OUT             0
+#define URB_DIR_MASK            URB_DIR_IN
+
 struct usb_iso_packet_descriptor {
         unsigned int offset;
         unsigned int length;            /* expected length */
@@ -1380,6 +1386,30 @@ extern void usb_unanchor_urb(struct urb *urb);
 extern int usb_wait_anchor_empty_timeout(struct usb_anchor *anchor,
                                          unsigned int timeout);
 
+/**
+ * usb_urb_dir_in - check if an URB describes an IN transfer
+ * @urb: URB to be checked
+ *
+ * Returns 1 if @urb describes an IN transfer (device-to-host),
+ * otherwise 0.
+ */
+static inline int usb_urb_dir_in(struct urb *urb)
+{
+        return (urb->transfer_flags & URB_DIR_MASK) != URB_DIR_OUT;
+}
+
+/**
+ * usb_urb_dir_out - check if an URB describes an OUT transfer
+ * @urb: URB to be checked
+ *
+ * Returns 1 if @urb describes an OUT transfer (host-to-device),
+ * otherwise 0.
+ */
+static inline int usb_urb_dir_out(struct urb *urb)
+{
+        return (urb->transfer_flags & URB_DIR_MASK) == URB_DIR_OUT;
+}
+
 void *usb_buffer_alloc (struct usb_device *dev, size_t size,
         gfp_t mem_flags, dma_addr_t *dma);
 void usb_buffer_free (struct usb_device *dev, size_t size,