usb: sandbox: Initialize root hub's device speed to high speed

At present 'usb tree' shows that the root hub on the Sandbox USB
controller is at full speed. But its device descriptor says it's
USB 2.0, so let's report it as a high speed device.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/drivers/usb/host/usb-sandbox.c b/drivers/usb/host/usb-sandbox.c
index 5e3d96c..f85d36b 100644
--- a/drivers/usb/host/usb-sandbox.c
+++ b/drivers/usb/host/usb-sandbox.c
@@ -12,6 +12,10 @@
 
 DECLARE_GLOBAL_DATA_PTR;
 
+struct sandbox_usb_ctrl {
+	int rootdev;
+};
+
 static void usbmon_trace(struct udevice *bus, ulong pipe,
 			 struct devrequest *setup, struct udevice *emul)
 {
@@ -40,6 +44,7 @@
 				      void *buffer, int length,
 				      struct devrequest *setup)
 {
+	struct sandbox_usb_ctrl *ctrl = dev_get_priv(bus);
 	struct udevice *emul;
 	int ret;
 
@@ -49,6 +54,14 @@
 	usbmon_trace(bus, pipe, setup, emul);
 	if (ret)
 		return ret;
+
+	if (usb_pipedevice(pipe) == ctrl->rootdev) {
+		if (setup->request == USB_REQ_SET_ADDRESS) {
+			debug("%s: Set root hub's USB address\n", __func__);
+			ctrl->rootdev = le16_to_cpu(setup->value);
+		}
+	}
+
 	ret = usb_emul_control(emul, udev, pipe, buffer, length, setup);
 	if (ret < 0) {
 		debug("ret=%d\n", ret);
@@ -107,6 +120,16 @@
 
 static int sandbox_alloc_device(struct udevice *dev, struct usb_device *udev)
 {
+	struct sandbox_usb_ctrl *ctrl = dev_get_priv(dev);
+
+	/*
+	 * Root hub will be the first device to be initailized.
+	 * If this device is a root hub, initialize its device speed
+	 * to high speed as we are a USB 2.0 controller.
+	 */
+	if (ctrl->rootdev == 0)
+		udev->speed = USB_SPEED_HIGH;
+
 	return 0;
 }
 
@@ -133,4 +156,5 @@
 	.of_match = sandbox_usb_ids,
 	.probe = sandbox_usb_probe,
 	.ops	= &sandbox_usb_ops,
+	.priv_auto_alloc_size = sizeof(struct sandbox_usb_ctrl),
 };