usb: implement macro for initializing USB strings

This uses the new unicode string literal feature that is available
now to greatly simplify the initialization of these special string
types. This makes them much more readable at a quick glance.

Change-Id: Iad8b49aa763486608e3bb7e83fb8abfb48ce0a7b

2 files changed, 11 insertions, 22 deletions

diff --git a/utils/hwstub/stub/main.c b/utils/hwstub/stub/main.c
index 7b6b02b83a..9e2e7116df 100644
--- a/utils/hwstub/stub/main.c
+++ b/utils/hwstub/stub/main.c
@@ -95,35 +95,17 @@ static struct usb_interface_descriptor interface_descriptor =
 };
 
 static const struct usb_string_descriptor usb_string_iManufacturer =
-{
-    24,
-    USB_DT_STRING,
-    {'R', 'o', 'c', 'k', 'b', 'o', 'x', '.', 'o', 'r', 'g'}
-};
+USB_STRING_INITIALIZER(u"Rockbox.org");
 
 static const struct usb_string_descriptor usb_string_iProduct =
-{
-    44,
-    USB_DT_STRING,
-    {'R', 'o', 'c', 'k', 'b', 'o', 'x', ' ',
-     'h', 'a', 'r', 'd', 'w', 'a', 'r', 'e', ' ',
-     's', 't', 'u', 'b'}
-};
+USB_STRING_INITIALIZER(u"Rockbox hardware stub");
 
 static const struct usb_string_descriptor usb_string_iInterface =
-{
-    14,
-    USB_DT_STRING,
-    {'H', 'W', 'S', 't', 'u', 'b'}
-};
+USB_STRING_INITIALIZER(u"HWStub");
 
 /* this is stringid #0: languages supported */
 static const struct usb_string_descriptor lang_descriptor =
-{
-    4,
-    USB_DT_STRING,
-    {0x0409} /* LANGID US English */
-};
+USB_STRING_INITIALIZER(u"\x0409"); /* LANGID US English */
 
 static struct hwstub_version_desc_t version_descriptor =
 {
diff --git a/utils/hwstub/stub/usb_drv.h b/utils/hwstub/stub/usb_drv.h
index 00f22d8e1a..ef032f52a3 100644
--- a/utils/hwstub/stub/usb_drv.h
+++ b/utils/hwstub/stub/usb_drv.h
@@ -43,5 +43,12 @@ void usb_drv_set_address(int address);
 int usb_drv_port_speed(void);
 void usb_drv_configure_endpoint(int ep_num, int type);
 
+/* USB_STRING_INITIALIZER(u"Example String") */
+#define USB_STRING_INITIALIZER(S) { \
+    sizeof(struct usb_string_descriptor) + sizeof(S) - sizeof(*S), \
+    USB_DT_STRING, \
+    S \
+}
+
 #endif /* _USB_DRV_H */