Back out use on inline functions to access 16-bit registers. The inline functions were a work-around for misbehaving compiler years and years ago. The mon standard macro-ized version should work just fine.

arch/arm/src/common/up_arch.h

@@ -1,7 +1,7 @@
 /****************************************************************************
  * arch/arm/src/common/up_arch.h
  *
- *   Copyright (C) 2007-2009 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007-2009, 2017 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -45,10 +45,6 @@
 # include <stdint.h>
 #endif
 
-/****************************************************************************
- * Pre-processor Definitions
- ****************************************************************************/
-
 /****************************************************************************
  * Inline Functions
  ****************************************************************************/
@@ -57,27 +53,11 @@
 
 # define getreg8(a)           (*(volatile uint8_t *)(a))
 # define putreg8(v,a)         (*(volatile uint8_t *)(a) = (v))
+# define getreg16(a)          (*(volatile uint16_t *)(a))
+# define putreg16(v,a)        (*(volatile uint16_t *)(a) = (v))
 # define getreg32(a)          (*(volatile uint32_t *)(a))
 # define putreg32(v,a)        (*(volatile uint32_t *)(a) = (v))
 
-/* Some compiler options will convert short loads and stores into byte loads
- * and stores.  We don't want this to happen for IO reads and writes!
- */
-
-/* # define getreg16(a)       (*(volatile uint16_t *)(a)) */
-static inline uint16_t getreg16(unsigned int addr)
-{
-  uint16_t retval;
- __asm__ __volatile__("\tldrh %0, [%1]\n\t" : "=r"(retval) : "r"(addr));
-  return retval;
-}
-
-/* define putreg16(v,a)       (*(volatile uint16_t *)(a) = (v)) */
-static inline void putreg16(uint16_t val, unsigned int addr)
-{
- __asm__ __volatile__("\tstrh %0, [%1]\n\t": : "r"(val), "r"(addr));
-}
-
 /****************************************************************************
  * Public Function Prototypes
  ****************************************************************************/