[usb] Select preferred USB device configuration based on driver score

Generate a score for each possible USB device configuration based on
the available driver support, and select the configuration with the
highest score.  This will allow us to prefer ECM over RNDIS (for
devices which support both) and will allow us to meaningfully select a
configuration even when we have drivers available for all functions
(e.g. when exposing unused functions via EFI_USB_IO_PROTOCOL).

Signed-off-by: Michael Brown <mcb30@ipxe.org>

1 files changed, 39 insertions, 9 deletions

diff --git a/src/include/ipxe/usb.h b/src/include/ipxe/usb.h
index 0640f9e3..8fee00e5 100644
--- a/src/include/ipxe/usb.h
+++ b/src/include/ipxe/usb.h
@@ -616,6 +616,23 @@ extern int usb_refill ( struct usb_endpoint *ep );
 extern void usb_flush ( struct usb_endpoint *ep );
 
 /**
+ * A USB function descriptor
+ *
+ * This is an internal descriptor used to represent an association of
+ * interfaces within a USB device.
+ */
+struct usb_function_descriptor {
+	/** Vendor ID */
+	uint16_t vendor;
+	/** Product ID */
+	uint16_t product;
+	/** Class */
+	struct usb_class class;
+	/** Number of interfaces */
+	unsigned int count;
+};
+
+/**
  * A USB function
  *
  * A USB function represents an association of interfaces within a USB
@@ -626,10 +643,8 @@ struct usb_function {
 	const char *name;
 	/** USB device */
 	struct usb_device *usb;
-	/** Class */
-	struct usb_class class;
-	/** Number of interfaces */
-	unsigned int count;
+	/** Function descriptor */
+	struct usb_function_descriptor desc;
 	/** Generic device */
 	struct device dev;
 	/** List of functions within this USB device */
@@ -1161,7 +1176,7 @@ usb_get_device_descriptor ( struct usb_device *usb,
  * @v data		Configuration descriptor to fill in
  * @ret rc		Return status code
  */
-static inline __attribute (( always_inline )) int
+static inline __attribute__ (( always_inline )) int
 usb_get_config_descriptor ( struct usb_device *usb, unsigned int index,
 			    struct usb_configuration_descriptor *data,
 			    size_t len ) {
@@ -1296,6 +1311,12 @@ struct usb_driver {
 	struct usb_device_id *ids;
 	/** Number of entries in ID table */
 	unsigned int id_count;
+	/** Driver score
+	 *
+	 * This is used to determine the preferred configuration for a
+	 * USB device.
+	 */
+	unsigned int score;
 	/**
 	 * Probe device
 	 *
@@ -1319,9 +1340,18 @@ struct usb_driver {
 /** Declare a USB driver */
 #define __usb_driver __table_entry ( USB_DRIVERS, 01 )
 
-extern struct usb_driver * usb_find_driver ( unsigned int vendor,
-					     unsigned int product,
-					     struct usb_class *class,
-					     struct usb_device_id **id );
+/** USB driver scores */
+enum usb_driver_score {
+	/** Fallback driver (has no effect on overall score) */
+	USB_SCORE_FALLBACK = 0,
+	/** Deprecated driver */
+	USB_SCORE_DEPRECATED = 1,
+	/** Normal driver */
+	USB_SCORE_NORMAL = 2,
+};
+
+extern struct usb_driver *
+usb_find_driver ( struct usb_function_descriptor *desc,
+		  struct usb_device_id **id );
 
 #endif /* _IPXE_USB_H */