USB: introduce unmap_urb_setup_for_dma()

Split unmap_urb_for_dma() to allow just the setup buffer
to be unmapped. This allows HCDs to use PIO for the setup
buffer if it is not suitable for DMA.
Signed-off-by: Martin Fuzzey <mfuzzey@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/core/hcd.c

@@ -1263,10 +1263,8 @@ static void hcd_free_coherent(struct usb_bus *bus, dma_addr_t *dma_handle,
 	*dma_handle = 0;
 }
 
-void unmap_urb_for_dma(struct usb_hcd *hcd, struct urb *urb)
+void unmap_urb_setup_for_dma(struct usb_hcd *hcd, struct urb *urb)
 {
-	enum dma_data_direction dir;
-
 	if (urb->transfer_flags & URB_SETUP_MAP_SINGLE)
 		dma_unmap_single(hcd->self.controller,
 				urb->setup_dma,
@@ -1279,6 +1277,17 @@ void unmap_urb_for_dma(struct usb_hcd *hcd, struct urb *urb)
 				sizeof(struct usb_ctrlrequest),
 				DMA_TO_DEVICE);
 
+	/* Make it safe to call this routine more than once */
+	urb->transfer_flags &= ~(URB_SETUP_MAP_SINGLE | URB_SETUP_MAP_LOCAL);
+}
+EXPORT_SYMBOL_GPL(unmap_urb_setup_for_dma);
+
+void unmap_urb_for_dma(struct usb_hcd *hcd, struct urb *urb)
+{
+	enum dma_data_direction dir;
+
+	unmap_urb_setup_for_dma(hcd, urb);
+
 	dir = usb_urb_dir_in(urb) ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
 	if (urb->transfer_flags & URB_DMA_MAP_SG)
 		dma_unmap_sg(hcd->self.controller,
@@ -1303,8 +1312,7 @@ void unmap_urb_for_dma(struct usb_hcd *hcd, struct urb *urb)
 				dir);
 
 	/* Make it safe to call this routine more than once */
-	urb->transfer_flags &= ~(URB_SETUP_MAP_SINGLE | URB_SETUP_MAP_LOCAL |
-			URB_DMA_MAP_SG | URB_DMA_MAP_PAGE |
+	urb->transfer_flags &= ~(URB_DMA_MAP_SG | URB_DMA_MAP_PAGE |
 			URB_DMA_MAP_SINGLE | URB_MAP_LOCAL);
 }
 EXPORT_SYMBOL_GPL(unmap_urb_for_dma);

include/linux/usb/hcd.h

@@ -329,6 +329,7 @@ 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 void unmap_urb_setup_for_dma(struct usb_hcd *, struct urb *);
 extern void unmap_urb_for_dma(struct usb_hcd *, struct urb *);
 extern void usb_hcd_flush_endpoint(struct usb_device *udev,
 		struct usb_host_endpoint *ep);