1 files changed, 64 insertions, 32 deletions

diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
index eaa9a599df63..717de39627c7 100644
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -24,6 +24,7 @@
 #include <linux/kernel.h>
 #include <linux/slab.h>
 #include <linux/device.h>
+#include <linux/utsname.h>
 
 #include <linux/usb/composite.h>
 
@@ -69,6 +70,8 @@ static char *iSerialNumber;
 module_param(iSerialNumber, charp, 0);
 MODULE_PARM_DESC(iSerialNumber, "SerialNumber string");
 
+static char composite_manufacturer[50];
+
 /*-------------------------------------------------------------------------*/
 
 /**
@@ -599,6 +602,7 @@ static int get_string(struct usb_composite_dev *cdev,
 	struct usb_configuration	*c;
 	struct usb_function		*f;
 	int				len;
+	const char			*str;
 
 	/* Yes, not only is USB's I18N support probably more than most
 	 * folk will ever care about ... also, it's all supported here.
@@ -638,9 +642,29 @@ static int get_string(struct usb_composite_dev *cdev,
 		return s->bLength;
 	}
 
-	/* Otherwise, look up and return a specified string.  String IDs
-	 * are device-scoped, so we look up each string table we're told
-	 * about.  These lookups are infrequent; simpler-is-better here.
+	/* Otherwise, look up and return a specified string.  First
+	 * check if the string has not been overridden.
+	 */
+	if (cdev->manufacturer_override == id)
+		str = iManufacturer ?: composite->iManufacturer ?:
+			composite_manufacturer;
+	else if (cdev->product_override == id)
+		str = iProduct ?: composite->iProduct;
+	else if (cdev->serial_override == id)
+		str = iSerialNumber;
+	else
+		str = NULL;
+	if (str) {
+		struct usb_gadget_strings strings = {
+			.language = language,
+			.strings  = &(struct usb_string) { 0xff, str }
+		};
+		return usb_gadget_get_string(&strings, 0xff, buf);
+	}
+
+	/* String IDs are device-scoped, so we look up each string
+	 * table we're told about.  These lookups are infrequent;
+	 * simpler-is-better here.
 	 */
 	if (composite->strings) {
 		len = lookup_string(composite->strings, buf, language, id);
@@ -1025,26 +1049,17 @@ composite_unbind(struct usb_gadget *gadget)
 	composite = NULL;
 }
 
-static void
-string_override_one(struct usb_gadget_strings *tab, u8 id, const char *s)
+static u8 override_id(struct usb_composite_dev *cdev, u8 *desc)
 {
-	struct usb_string		*str = tab->strings;
-
-	for (str = tab->strings; str->s; str++) {
-		if (str->id == id) {
-			str->s = s;
-			return;
-		}
+	if (!*desc) {
+		int ret = usb_string_id(cdev);
+		if (unlikely(ret < 0))
+			WARNING(cdev, "failed to override string ID\n");
+		else
+			*desc = ret;
 	}
-}
 
-static void
-string_override(struct usb_gadget_strings **tab, u8 id, const char *s)
-{
-	while (*tab) {
-		string_override_one(*tab, id, s);
-		tab++;
-	}
+	return *desc;
 }
 
 static int composite_bind(struct usb_gadget *gadget)
@@ -1107,19 +1122,34 @@ static int composite_bind(struct usb_gadget *gadget)
 	cdev->desc = *composite->dev;
 	cdev->desc.bMaxPacketSize0 = gadget->ep0->maxpacket;
 
-	/* strings can't be assigned before bind() allocates the
-	 * releavnt identifiers
-	 */
-	if (cdev->desc.iManufacturer && iManufacturer)
-		string_override(composite->strings,
-			cdev->desc.iManufacturer, iManufacturer);
-	if (cdev->desc.iProduct && iProduct)
-		string_override(composite->strings,
-			cdev->desc.iProduct, iProduct);
-	if (cdev->desc.iSerialNumber && iSerialNumber)
-		string_override(composite->strings,
-			cdev->desc.iSerialNumber, iSerialNumber);
+	/* stirng overrides */
+	if (iManufacturer || !cdev->desc.iManufacturer) {
+		if (!iManufacturer && !composite->iManufacturer &&
+		    !*composite_manufacturer)
+			snprintf(composite_manufacturer,
+				 sizeof composite_manufacturer,
+				 "%s %s with %s",
+				 init_utsname()->sysname,
+				 init_utsname()->release,
+				 gadget->name);
+
+		cdev->manufacturer_override =
+			override_id(cdev, &cdev->desc.iManufacturer);
+	}
+
+	if (iProduct || (!cdev->desc.iProduct && composite->iProduct))
+		cdev->product_override =
+			override_id(cdev, &cdev->desc.iProduct);
+
+	if (iSerialNumber)
+		cdev->serial_override =
+			override_id(cdev, &cdev->desc.iSerialNumber);
+
+	/* has userspace failed to provide a serial number? */
+	if (composite->needs_serial && !cdev->desc.iSerialNumber)
+		WARNING(cdev, "userspace failed to provide iSerialNumber\n");
 
+	/* finish up */
 	status = device_create_file(&gadget->dev, &dev_attr_suspended);
 	if (status)
 		goto fail;
@@ -1217,6 +1247,8 @@ int usb_composite_register(struct usb_composite_driver *driver)
 	if (!driver || !driver->dev || !driver->bind || composite)
 		return -EINVAL;
 
+	if (!driver->iProduct)
+		driver->iProduct = driver->name;
 	if (!driver->name)
 		driver->name = "composite";
 	composite_driver.function =  (char *) driver->name;