Clarified ep_buffer.xc setup stall

Added getter hidIsReportDescriptorPrepared(),
allowing more readable logic in the setup phase of
ep_buffer.xc

lib_xua/src/core/buffer/ep/ep_buffer.xc

@@ -375,19 +375,13 @@ void XUA_Buffer_Ep(register chanend c_aud_out,
 #if( 0 < HID_CONTROLS )
     UserHIDInit();
     {
-        int hidReportLength = 0;
+        /* Stall until Report Descriptor has been prepared */
-        unsigned hidReportId;
+        while (!hidIsReportDescriptorPrepared());
-        while(0 == hidReportLength) {
-            for( hidReportId = 0U; hidReportId < hidGetReportIdLimit(); ++hidReportId) {
-                hidReportLength = (int) hidGetReportLength(hidReportId);
-                if(0 < hidReportLength) {
-                    break;
-                }
-            }
-        }
 
-        hidReportLength = (int) UserHIDGetData(hidReportId, g_hidData);
+        /* Get the last report - we don't really care which it is, so long as there's some data we can grab. */
-        XUD_SetReady_In(ep_hid, g_hidData, hidReportLength);
+        int hidReportLength = (int) UserHIDGetData(hidGetReportIdLimit() - 1, g_hidData); 
+
+        XUD_SetReady_In(ep_hid, g_hidData, hidReportLength)
     }
 #endif
 

lib_xua/src/hid/hid_report.c

@@ -213,6 +213,11 @@ unsigned hidGetNextReportTime( const unsigned id ) {
     return retVal;
 }
 
+unsigned hidIsReportDescriptorPrepared( void )
+{
+    return s_hidReportDescriptorPrepared;
+}
+
 unsigned char* hidGetReportDescriptor( void )
 {
     unsigned char* retVal = NULL;

lib_xua/src/hid/xua_hid_report.h

@@ -142,6 +142,15 @@ typedef struct
  */
 void hidClearChangePending( const unsigned id );
 
+/**
+ * @brief Indicate if the HID Report descriptor has been prepared
+ *
+ *  \returns  A Boolean indicating whether the HID Report descriptor has been prepared.
+ *  \retval   True  The HID Report descriptor has been prepared.
+ *  \retval   False The HID Report has not been prepared.
+ */
+ unsigned hidIsReportDescriptorPrepared( void );
+
 /**
  * @brief Get the HID Report descriptor
  *