dm: usb: Copy over usb_device values from usb_scan_device() to final usb_device

Currently we copy over a number of usb_device values stored in the on stack
struct usb_device probed in usb_scan_device() to the final driver-model managed
struct usb_device in usb_child_pre_probe() through usb_device_platdata, and
then call usb_select_config() to fill in the rest.

There are 3 problems with this approach:

1) It does not fill in enough fields before calling usb_select_config(),
specifically it does not fill in ep0's maxpacketsize causing a div by zero
exception in the ehci driver.

2) It unnecessarily redoes a number of usb requests making usb probing slower

3) Calling usb_select_config() a second time fails on some usb-1 devices
plugged into usb-2 hubs, causing u-boot to not recognize these devices.

This commit fixes these issues by removing (*) the usb_select_config() call
from usb_child_pre_probe(), and instead of copying over things field by field
through usb_device_platdata, store a pointer to the in stack usb_device
(which is still valid when usb_child_pre_probe() gets called) and copy
over the entire struct.

*) Except for devices which are explictly instantiated through device-tree
rather then discovered through usb_scan_device() such as emulated usb devices
in the sandbox.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Simon Glass <sjg@chromium.org>

drivers/usb/host/usb-uclass.c

@@ -533,11 +533,7 @@ int usb_scan_device(struct udevice *parent, int port,
 	plat = dev_get_parent_platdata(dev);
 	debug("%s: Probing '%s', plat=%p\n", __func__, dev->name, plat);
 	plat->devnum = udev->devnum;
-	plat->speed = udev->speed;
-	plat->slot_id = udev->slot_id;
-	plat->portnr = port;
-	debug("** device '%s': stashing slot_id=%d\n", dev->name,
-	      plat->slot_id);
+	plat->udev = udev;
 	priv->next_addr++;
 	ret = device_probe(dev);
 	if (ret) {
@@ -597,17 +593,34 @@ int usb_child_pre_probe(struct udevice *dev)
 	struct usb_dev_platdata *plat = dev_get_parent_platdata(dev);
 	int ret;
 
-	udev->controller_dev = usb_get_bus(dev);
-	udev->dev = dev;
-	udev->devnum = plat->devnum;
-	udev->slot_id = plat->slot_id;
-	udev->portnr = plat->portnr;
-	udev->speed = plat->speed;
-	debug("** device '%s': getting slot_id=%d\n", dev->name, plat->slot_id);
+	if (plat->udev) {
+		/*
+		 * Copy over all the values set in the on stack struct
+		 * usb_device in usb_scan_device() to our final struct
+		 * usb_device for this dev.
+		 */
+		*udev = *(plat->udev);
+		/* And clear plat->udev as it will not be valid for long */
+		plat->udev = NULL;
+		udev->dev = dev;
+	} else {
+		/*
+		 * This happens with devices which are explicitly bound
+		 * instead of being discovered through usb_scan_device()
+		 * such as sandbox emul devices.
+		 */
+		udev->dev = dev;
+		udev->controller_dev = usb_get_bus(dev);
+		udev->devnum = plat->devnum;
 
-	ret = usb_select_config(udev);
-	if (ret)
-		return ret;
+		/*
+		 * udev did not go through usb_scan_device(), so we need to
+		 * select the config and read the config descriptors.
+		 */
+		ret = usb_select_config(udev);
+		if (ret)
+			return ret;
+	}
 
 	return 0;
 }

include/usb.h

@@ -571,20 +571,23 @@ struct usb_platdata {
  * This is used by sandbox to provide emulation data also.
  *
  * @id:		ID used to match this device
- * @speed:	Stores the speed associated with a USB device
  * @devnum:	Device address on the USB bus
- * @slot_id:	USB3 slot ID, which is separate from the device address
- * @portnr:	Port number of this device on its parent hub, numbered from 1
- *		(0 mean this device is the root hub)
+ * @udev:	usb-uclass internal use only do NOT use
  * @strings:	List of descriptor strings (for sandbox emulation purposes)
  * @desc_list:	List of descriptors (for sandbox emulation purposes)
  */
 struct usb_dev_platdata {
 	struct usb_device_id id;
-	enum usb_device_speed speed;
 	int devnum;
-	int slot_id;
-	int portnr;	/* Hub port number, 1..n */
+	/*
+	 * This pointer is used to pass the usb_device used in usb_scan_device,
+	 * to get the usb descriptors before the driver is known, to the
+	 * actual udevice once the driver is known and the udevice is created.
+	 * This will be NULL except during probe, do NOT use.
+	 *
+	 * This should eventually go away.
+	 */
+	struct usb_device *udev;
 #ifdef CONFIG_SANDBOX
 	struct usb_string *strings;
 	/* NULL-terminated list of descriptor pointers */