usb: gadget: f_rndis: OS descriptors support

In order for usb functions to expose OS descriptors they
need to be made aware of OS descriptors. This involves
extending the "options" structure and setting up
appropriate associations.
Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/f_rndis.c

@@ -682,6 +682,15 @@ rndis_bind(struct usb_configuration *c, struct usb_function *f)
 
 	rndis_opts = container_of(f->fi, struct f_rndis_opts, func_inst);
 
+	if (cdev->use_os_string) {
+		f->os_desc_table = kzalloc(sizeof(*f->os_desc_table),
+					   GFP_KERNEL);
+		if (!f->os_desc_table)
+			return PTR_ERR(f->os_desc_table);
+		f->os_desc_n = 1;
+		f->os_desc_table[0].os_desc = &rndis_opts->rndis_os_desc;
+	}
+
 	/*
 	 * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
 	 * configurations are bound in sequence with list_for_each_entry,
@@ -693,14 +702,16 @@ rndis_bind(struct usb_configuration *c, struct usb_function *f)
 		gether_set_gadget(rndis_opts->net, cdev->gadget);
 		status = gether_register_netdev(rndis_opts->net);
 		if (status)
-			return status;
+			goto fail;
 		rndis_opts->bound = true;
 	}
 
 	us = usb_gstrings_attach(cdev, rndis_strings,
 				 ARRAY_SIZE(rndis_string_defs));
-	if (IS_ERR(us))
-		return PTR_ERR(us);
+	if (IS_ERR(us)) {
+		status = PTR_ERR(us);
+		goto fail;
+	}
 	rndis_control_intf.iInterface = us[0].id;
 	rndis_data_intf.iInterface = us[1].id;
 	rndis_iad_descriptor.iFunction = us[2].id;
@@ -802,6 +813,8 @@ rndis_bind(struct usb_configuration *c, struct usb_function *f)
 	return 0;
 
 fail:
+	kfree(f->os_desc_table);
+	f->os_desc_n = 0;
 	usb_free_all_descriptors(f);
 
 	if (rndis->notify_req) {
@@ -892,6 +905,8 @@ static struct usb_function_instance *rndis_alloc_inst(void)
 	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
 	if (!opts)
 		return ERR_PTR(-ENOMEM);
+	opts->rndis_os_desc.ext_compat_id = opts->rndis_ext_compat_id;
+
 	mutex_init(&opts->lock);
 	opts->func_inst.free_func_inst = rndis_free_inst;
 	opts->net = gether_setup_default();
@@ -900,6 +915,7 @@ static struct usb_function_instance *rndis_alloc_inst(void)
 		kfree(opts);
 		return ERR_CAST(net);
 	}
+	INIT_LIST_HEAD(&opts->rndis_os_desc.ext_prop);
 
 	config_group_init_type_name(&opts->func_inst.group, "",
 				    &rndis_func_type);
@@ -925,6 +941,8 @@ static void rndis_unbind(struct usb_configuration *c, struct usb_function *f)
 {
 	struct f_rndis		*rndis = func_to_rndis(f);
 
+	kfree(f->os_desc_table);
+	f->os_desc_n = 0;
 	usb_free_all_descriptors(f);
 
 	kfree(rndis->notify_req->buf);

drivers/usb/gadget/u_rndis.h

@@ -26,6 +26,9 @@ struct f_rndis_opts {
 	bool				bound;
 	bool				borrowed_net;
 
+	struct usb_os_desc		rndis_os_desc;
+	char				rndis_ext_compat_id[16];
+
 	/*
 	 * Read/write access to configfs attributes is handled by configfs.
 	 *