usb: gadget: udc: core: add usb_gadget_{un}map_request_by_dev()

If the following environment, the first argument of DMA API should
be set to a DMAC's device structure, not a udc controller's one.
 - A udc controller needs an external DMAC device (like a DMA Engine).
 - The external DMAC enables IOMMU.

So, this patch add usb_gadget_{un}map_request_by_dev() API to set
a DMAC's device structure by a udc controller driver.

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/gadget/udc/udc-core.c

@@ -61,11 +61,9 @@ static int udc_bind_to_driver(struct usb_udc *udc,
 
 #ifdef	CONFIG_HAS_DMA
 
-int usb_gadget_map_request(struct usb_gadget *gadget,
+int usb_gadget_map_request_by_dev(struct device *dev,
 		struct usb_request *req, int is_in)
 {
-	struct device *dev = gadget->dev.parent;
-
 	if (req->length == 0)
 		return 0;
 
@@ -92,24 +90,38 @@ int usb_gadget_map_request(struct usb_gadget *gadget,
 
 	return 0;
 }
+EXPORT_SYMBOL_GPL(usb_gadget_map_request_by_dev);
+
+int usb_gadget_map_request(struct usb_gadget *gadget,
+		struct usb_request *req, int is_in)
+{
+	return usb_gadget_map_request_by_dev(gadget->dev.parent, req, is_in);
+}
 EXPORT_SYMBOL_GPL(usb_gadget_map_request);
 
-void usb_gadget_unmap_request(struct usb_gadget *gadget,
+void usb_gadget_unmap_request_by_dev(struct device *dev,
 		struct usb_request *req, int is_in)
 {
 	if (req->length == 0)
 		return;
 
 	if (req->num_mapped_sgs) {
-		dma_unmap_sg(gadget->dev.parent, req->sg, req->num_mapped_sgs,
+		dma_unmap_sg(dev, req->sg, req->num_mapped_sgs,
 				is_in ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
 
 		req->num_mapped_sgs = 0;
 	} else {
-		dma_unmap_single(gadget->dev.parent, req->dma, req->length,
+		dma_unmap_single(dev, req->dma, req->length,
 				is_in ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
 	}
 }
+EXPORT_SYMBOL_GPL(usb_gadget_unmap_request_by_dev);
+
+void usb_gadget_unmap_request(struct usb_gadget *gadget,
+		struct usb_request *req, int is_in)
+{
+	usb_gadget_unmap_request_by_dev(gadget->dev.parent, req, is_in);
+}
 EXPORT_SYMBOL_GPL(usb_gadget_unmap_request);
 
 #endif	/* CONFIG_HAS_DMA */

include/linux/usb/gadget.h

@@ -1223,9 +1223,13 @@ int usb_otg_descriptor_init(struct usb_gadget *gadget,
 
 /* utility to simplify map/unmap of usb_requests to/from DMA */
 
+extern int usb_gadget_map_request_by_dev(struct device *dev,
+		struct usb_request *req, int is_in);
 extern int usb_gadget_map_request(struct usb_gadget *gadget,
 		struct usb_request *req, int is_in);
 
+extern void usb_gadget_unmap_request_by_dev(struct device *dev,
+		struct usb_request *req, int is_in);
 extern void usb_gadget_unmap_request(struct usb_gadget *gadget,
 		struct usb_request *req, int is_in);