From 255e9f75b543aa8d9bdcf1cfb67a303f116712e0 Mon Sep 17 00:00:00 2001
From: Michael Banther <michaelb@xmos.com>
Date: Thu, 5 Dec 2019 16:45:11 +0000
Subject: [PATCH 1/3] Add missing header file guards.

---
 lib_xua/src/core/user/hid/user_hid.h | 4 ++++
 lib_xua/src/hid/xua_hid.h            | 6 ++++++
 2 files changed, 10 insertions(+)

diff --git a/lib_xua/src/core/user/hid/user_hid.h b/lib_xua/src/core/user/hid/user_hid.h
index 88165b2a..7d67b00c 100644
--- a/lib_xua/src/core/user/hid/user_hid.h
+++ b/lib_xua/src/core/user/hid/user_hid.h
@@ -1,5 +1,8 @@
 // Copyright (c) 2013-2019, XMOS Ltd, All rights reserved
 
+#ifndef __USER_HID_H__
+#define __USER_HID_H__
+
 /* These defines relate to the HID report desc - do not mod */
 #define HID_CONTROL_PLAYPAUSE_SHIFT  0x00
 #define HID_CONTROL_NEXT_SHIFT       0x01
@@ -17,3 +20,4 @@ void UserReadHIDData( unsigned char hidData[ HID_DATA_SIZE ]);
 void UserSetHIDData( const unsigned hidData );
 
 #endif /* ( 0 < HID_CONTROLS ) */
+#endif /* __USER_HID_H__ */
diff --git a/lib_xua/src/hid/xua_hid.h b/lib_xua/src/hid/xua_hid.h
index 23d507e0..63469054 100644
--- a/lib_xua/src/hid/xua_hid.h
+++ b/lib_xua/src/hid/xua_hid.h
@@ -1,4 +1,8 @@
 // Copyright (c) 2019, XMOS Ltd, All rights reserved
+
+#ifndef __XUA_HID_H__
+#define __XUA_HID_H__
+
 #include <xs1.h>
 #include <xccompat.h>
 #include "xud.h"
@@ -53,3 +57,5 @@ XUD_Result_t HidInterfaceClassRequests(
  *  \retval   0 -- Send the HID Report
  */
 unsigned HidIsSetIdleSilenced( void );
+
+#endif // __XUA_HID_H__

From 83284620ccc6cf9dd3ce8b2f38724924ede7a4af Mon Sep 17 00:00:00 2001
From: Michael Banther <michaelb@xmos.com>
Date: Thu, 5 Dec 2019 16:45:49 +0000
Subject: [PATCH 2/3] Explain the need for using the assembler gettime
 operation instead of an XC timer more fully.

---
 lib_xua/src/hid/hid.xc | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/lib_xua/src/hid/hid.xc b/lib_xua/src/hid/hid.xc
index 478bfea5..854b78d3 100644
--- a/lib_xua/src/hid/hid.xc
+++ b/lib_xua/src/hid/hid.xc
@@ -57,7 +57,10 @@ unsigned HidIsSetIdleSilenced( void )
 
   if( s_hidIdleActive ) {
     unsigned currentTime;
-    asm volatile( "gettime %0" : "=r" ( currentTime )); // Use inline assembly to access the time without creating a side-effect
+    // Use inline assembly to access the time without creating a side-effect.
+    // The mapper complains if the time comes from an XC timer because this function is called in the guard of a select case.
+    // Appearently the use of a timer creates a side-effect that prohibits the operation of the select functionality.
+    asm volatile( "gettime %0" : "=r" ( currentTime ));
     isSilenced = ( s_hidIndefiniteDuration || ( timeafter( s_hidNextReportTime, currentTime )));
   }
 

From 746635b2eb48dd7eb39024a6c755184a18983741 Mon Sep 17 00:00:00 2001
From: Michael Banther <michaelb@xmos.com>
Date: Thu, 5 Dec 2019 18:01:14 +0000
Subject: [PATCH 3/3] Update change log.

---
 CHANGELOG.rst | 1 +
 1 file changed, 1 insertion(+)

diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 11d15168..d8b82f4a 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -10,6 +10,7 @@ lib_xua Change Log
   * ADDED:     Pre-processor symbols to enable single-threaded, dual-PDM
     microphone operation
   * FIXED:     Descriptors for XUA_ADAPTIVE incorrectly defined for IN endpoint
+  * ADDED:     Guards to user_hid.h and xua_hid.h
 
 0.2.1
 -----