USB: HCD: Add driver hooks for (un)?map_urb_for_dma

Provide optional hooks for the host controller driver to override the
default DMA mapping and unmapping routines.  In general, these 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.
Also, pass the status to unmap_urb_for_dma so it can know whether the
DMA buffer has been overwritten.

Finally, add a flag to be used by these implementations if they
allocated a temporary buffer so it can be freed properly when unmapping.

Signed-off-by: Robert Morell <rmorell@nvidia.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 15 insertions, 0 deletions

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,