usb: gadget: composite: let USB functions process ctrl reqs in cfg0

It can sometimes be necessary for gadget drivers to process non-standard
control requests, which host devices can send without having sent
USB_REQ_SET_CONFIGURATION.

Therefore, the req_match() usb_function method is enhanced with the new
parameter "config0". When a USB configuration is active, this parameter
is false. When a non-core control request is processed in
composite_setup(), without an active configuration, req_match() of the
USB functions of all available configurations which implement this
function, is called with config0=true. Then the control request gets
processed by the first usb_function instance whose req_match() returns
true.
Signed-off-by: Felix Hädicke <felixhaedicke@web.de>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/gadget/composite.c

@@ -1893,17 +1893,21 @@ composite_setup(struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
 		/* functions always handle their interfaces and endpoints...
 		 * punt other recipients (other, WUSB, ...) to the current
 		 * configuration code.
-		 *
-		 * REVISIT it could make sense to let the composite device
-		 * take such requests too, if that's ever needed:  to work
-		 * in config 0, etc.
 		 */
 		if (cdev->config) {
 			list_for_each_entry(f, &cdev->config->functions, list)
-				if (f->req_match && f->req_match(f, ctrl))
+				if (f->req_match &&
+				    f->req_match(f, ctrl, false))
 					goto try_fun_setup;
-			f = NULL;
+		} else {
+			struct usb_configuration *c;
+			list_for_each_entry(c, &cdev->configs, list)
+				list_for_each_entry(f, &c->functions, list)
+					if (f->req_match &&
+					    f->req_match(f, ctrl, true))
+						goto try_fun_setup;
 		}
+		f = NULL;
 
 		switch (ctrl->bRequestType & USB_RECIP_MASK) {
 		case USB_RECIP_INTERFACE:

drivers/usb/gadget/function/f_fs.c

@@ -99,7 +99,8 @@ static void ffs_func_disable(struct usb_function *);
 static int ffs_func_setup(struct usb_function *,
 			  const struct usb_ctrlrequest *);
 static bool ffs_func_req_match(struct usb_function *,
-			       const struct usb_ctrlrequest *);
+			       const struct usb_ctrlrequest *,
+			       bool config0);
 static void ffs_func_suspend(struct usb_function *);
 static void ffs_func_resume(struct usb_function *);
 
@@ -3136,10 +3137,14 @@ static int ffs_func_setup(struct usb_function *f,
 }
 
 static bool ffs_func_req_match(struct usb_function *f,
-			       const struct usb_ctrlrequest *creq)
+			       const struct usb_ctrlrequest *creq,
+			       bool config0)
 {
 	struct ffs_function *func = ffs_func_from_usb(f);
 
+	if (config0)
+		return false;
+
 	switch (creq->bRequestType & USB_RECIP_MASK) {
 	case USB_RECIP_INTERFACE:
 		return ffs_func_revmap_intf(func,

drivers/usb/gadget/function/f_printer.c

@@ -889,13 +889,17 @@ static void printer_soft_reset(struct printer_dev *dev)
 /*-------------------------------------------------------------------------*/
 
 static bool gprinter_req_match(struct usb_function *f,
-			       const struct usb_ctrlrequest *ctrl)
+			       const struct usb_ctrlrequest *ctrl,
+			       bool config0)
 {
 	struct printer_dev	*dev = func_to_printer(f);
 	u16			w_index = le16_to_cpu(ctrl->wIndex);
 	u16			w_value = le16_to_cpu(ctrl->wValue);
 	u16			w_length = le16_to_cpu(ctrl->wLength);
 
+	if (config0)
+		return false;
+
 	if ((ctrl->bRequestType & USB_RECIP_MASK) != USB_RECIP_INTERFACE ||
 	    (ctrl->bRequestType & USB_TYPE_MASK) != USB_TYPE_CLASS)
 		return false;

include/linux/usb/composite.h

@@ -220,7 +220,8 @@ struct usb_function {
 	int			(*setup)(struct usb_function *,
 					const struct usb_ctrlrequest *);
 	bool			(*req_match)(struct usb_function *,
-					const struct usb_ctrlrequest *);
+					const struct usb_ctrlrequest *,
+					bool config0);
 	void			(*suspend)(struct usb_function *);
 	void			(*resume)(struct usb_function *);