[PATCH v2 1/2] USB: Add driver hooks for (un)?map_urb_for_dma

[Robert Morell <rmorell@nvidia.com>]

These are useful in case your device has quirks involving what memory
is and is not DMAable.

Signed-off-by: Robert Morell <rmorell@nvidia.com>
Reviewed-by: Scott Williams <scwilliams@nvidia.com>
Reviewed-by: Janne Hellsten <jhellsten@nvidia.com>
---
 drivers/usb/core/hcd.c  |   19 ++++++++++++++++++-
 include/linux/usb/hcd.h |    8 ++++++++
 2 files changed, 26 insertions(+), 1 deletions(-)

diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index 5cca00a..84fee0f 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -1265,6 +1265,14 @@ static void hcd_free_coherent(struct usb_bus *bus, dma_addr_t *dma_handle,
 
 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;
 
 	if (urb->transfer_flags & URB_SETUP_MAP_SINGLE)
@@ -1311,6 +1319,15 @@ static void unmap_urb_for_dma(struct usb_hcd *hcd, struct urb *urb)
 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;
 
@@ -1400,7 +1417,7 @@ static int map_urb_for_dma(struct usb_hcd *hcd, struct urb *urb,
 		}
 		if (ret && (urb->transfer_flags & (URB_SETUP_MAP_SINGLE |
 				URB_SETUP_MAP_LOCAL)))
-			unmap_urb_for_dma(hcd, urb);
+			usb_hcd_unmap_urb_for_dma(hcd, urb);
 	}
 	return ret;
 }
diff --git a/include/linux/usb/hcd.h b/include/linux/usb/hcd.h
index 3b571f1..8aaf687 100644
--- a/include/linux/usb/hcd.h
+++ b/include/linux/usb/hcd.h
@@ -233,6 +233,11 @@ struct hc_driver {
 	int	(*urb_dequeue)(struct usb_hcd *hcd,
 				struct urb *urb, int status);
 
+	/* dma support */
+	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);
@@ -327,6 +332,9 @@ extern void usb_hcd_unlink_urb_from_ep(struct usb_hcd *hcd, struct urb *urb);
 
 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 int usb_hcd_map_urb_for_dma(struct usb_hcd *hcd, struct urb *urb,
+		gfp_t mem_flags);
+extern void usb_hcd_unmap_urb_for_dma(struct usb_hcd *hcd, struct urb *urb);
 extern void usb_hcd_giveback_urb(struct usb_hcd *hcd, struct urb *urb,
 		int status);
 extern void usb_hcd_flush_endpoint(struct usb_device *udev,
-- 
1.7.2.2