3 files changed, 36 insertions, 2 deletions

diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index 335c1ddb260d..d0b782c4523a 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -1281,6 +1281,14 @@ void usb_hcd_unmap_urb_setup_for_dma(struct usb_hcd *hcd, struct urb *urb)
 }
 EXPORT_SYMBOL_GPL(usb_hcd_unmap_urb_setup_for_dma);
 
+static void unmap_urb_for_dma(struct usb_hcd *hcd, struct urb *urb)
+{
+        if (hcd->driver->unmap_urb_for_dma)
+                hcd->driver->unmap_urb_for_dma(hcd, urb);
+        else
+                usb_hcd_unmap_urb_for_dma(hcd, urb);
+}
+
 void usb_hcd_unmap_urb_for_dma(struct usb_hcd *hcd, struct urb *urb)
 {
         enum dma_data_direction dir;
@@ -1319,6 +1327,15 @@ EXPORT_SYMBOL_GPL(usb_hcd_unmap_urb_for_dma);
 static int map_urb_for_dma(struct usb_hcd *hcd, struct urb *urb,
                            gfp_t mem_flags)
 {
+        if (hcd->driver->map_urb_for_dma)
+                return hcd->driver->map_urb_for_dma(hcd, urb, mem_flags);
+        else
+                return usb_hcd_map_urb_for_dma(hcd, urb, mem_flags);
+}
+
+int usb_hcd_map_urb_for_dma(struct usb_hcd *hcd, struct urb *urb,
+                            gfp_t mem_flags)
+{
         enum dma_data_direction dir;
         int ret = 0;
 
@@ -1414,6 +1431,7 @@ static int map_urb_for_dma(struct usb_hcd *hcd, struct urb *urb,
         }
         return ret;
 }
+EXPORT_SYMBOL_GPL(usb_hcd_map_urb_for_dma);
 
 /*-------------------------------------------------------------------------*/
 
@@ -1451,7 +1469,7 @@ int usb_hcd_submit_urb (struct urb *urb, gfp_t mem_flags)
                 if (likely(status == 0)) {
                         status = hcd->driver->urb_enqueue(hcd, urb, mem_flags);
                         if (unlikely(status))
-                                usb_hcd_unmap_urb_for_dma(hcd, urb);
+                                unmap_urb_for_dma(hcd, urb);
                 }
         }
 
@@ -1557,7 +1575,7 @@ void usb_hcd_giveback_urb(struct usb_hcd *hcd, struct urb *urb, int status)
                         !status))
                 status = -EREMOTEIO;
 
-        usb_hcd_unmap_urb_for_dma(hcd, urb);
+        unmap_urb_for_dma(hcd, urb);
         usbmon_urb_complete(&hcd->self, urb, status);
         usb_unanchor_urb(urb);
 
diff --git a/include/linux/usb.h b/include/linux/usb.h
index bd69b65f3356..e63efeb378e3 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -976,6 +976,7 @@ extern int usb_disabled(void);
 #define URB_SETUP_MAP_SINGLE    0x00100000      /* Setup packet DMA mapped */
 #define URB_SETUP_MAP_LOCAL     0x00200000      /* HCD-local setup packet */
 #define URB_DMA_SG_COMBINED     0x00400000      /* S-G entries were combined */
+#define URB_ALIGNED_TEMP_BUFFER 0x00800000      /* Temp buffer was alloc'd */
 
 struct usb_iso_packet_descriptor {
         unsigned int offset;
diff --git a/include/linux/usb/hcd.h b/include/linux/usb/hcd.h
index 395704bdf5cc..92b96fe39307 100644
--- a/include/linux/usb/hcd.h
+++ b/include/linux/usb/hcd.h
@@ -233,6 +233,19 @@ struct hc_driver {
         int     (*urb_dequeue)(struct usb_hcd *hcd,
                                 struct urb *urb, int status);
 
+        /*
+         * (optional) these hooks allow an HCD to override the default DMA
+         * mapping and unmapping routines.  In general, they shouldn't be
+         * necessary unless the host controller has special DMA requirements,
+         * such as alignment contraints.  If these are not specified, the
+         * general usb_hcd_(un)?map_urb_for_dma functions will be used instead
+         * (and it may be a good idea to call these functions in your HCD
+         * implementation)
+         */
+        int     (*map_urb_for_dma)(struct usb_hcd *hcd, struct urb *urb,
+                                   gfp_t mem_flags);
+        void    (*unmap_urb_for_dma)(struct usb_hcd *hcd, struct urb *urb);
+
         /* hw synch, freeing endpoint resources that urb_dequeue can't */
         void    (*endpoint_disable)(struct usb_hcd *hcd,
                         struct usb_host_endpoint *ep);
@@ -329,6 +342,8 @@ extern int usb_hcd_submit_urb(struct urb *urb, gfp_t mem_flags);
 extern int usb_hcd_unlink_urb(struct urb *urb, int status);
 extern void usb_hcd_giveback_urb(struct usb_hcd *hcd, struct urb *urb,
                 int status);
+extern int usb_hcd_map_urb_for_dma(struct usb_hcd *hcd, struct urb *urb,
+                gfp_t mem_flags);
 extern void usb_hcd_unmap_urb_setup_for_dma(struct usb_hcd *, struct urb *);
 extern void usb_hcd_unmap_urb_for_dma(struct usb_hcd *, struct urb *);
 extern void usb_hcd_flush_endpoint(struct usb_device *udev,