diff --git a/arch/arm/src/samd2l2/sam_lowputc.c b/arch/arm/src/samd2l2/sam_lowputc.c
index bfd0dcc10a..67d70b370c 100644
--- a/arch/arm/src/samd2l2/sam_lowputc.c
+++ b/arch/arm/src/samd2l2/sam_lowputc.c
@@ -90,7 +90,7 @@
 
 #ifdef SAMD2L2_HAVE_USART
 static void
-sam_wait_synchronization(const struct sam_usart_config_s * const config)
+sam_wait_synchronization(const struct sam_usart_config_s *const config)
 {
   while (usart_syncbusy(config));
 }
@@ -106,7 +106,7 @@ sam_wait_synchronization(const struct sam_usart_config_s * const config)
 
 #ifdef SAMD2L2_HAVE_USART
 static inline int
-sam_usart_configure(const struct sam_usart_config_s * const config)
+sam_usart_configure(const struct sam_usart_config_s *const config)
 {
   uint32_t ctrla;
   uint32_t ctrlb;
@@ -257,7 +257,7 @@ sam_usart_configure(const struct sam_usart_config_s * const config)
 
 #ifdef SAMD2L2_HAVE_USART
 static inline void
-sam_pad_configure(const struct sam_usart_config_s * const config)
+sam_pad_configure(const struct sam_usart_config_s *const config)
 {
   /* Configure SERCOM pads */
 
@@ -294,7 +294,7 @@ sam_pad_configure(const struct sam_usart_config_s * const config)
  ****************************************************************************/
 
 #ifdef SAMD2L2_HAVE_USART
-int sam_usart_internal(const struct sam_usart_config_s * const config)
+int sam_usart_internal(const struct sam_usart_config_s *const config)
 {
 #ifdef CONFIG_ARCH_FAMILY_SAML21
   int channel;
@@ -339,34 +339,6 @@ int sam_usart_internal(const struct sam_usart_config_s * const config)
 }
 #endif
 
-/****************************************************************************
- * Name: sam_usart_enable
- *
- * Description:
- *   Enable the SERCOM USART (without enabling interrupts).
- *
- ****************************************************************************/
-
-#ifdef SAMD2L2_HAVE_USART
-static inline void
-sam_usart_enable(const struct sam_usart_config_s * const config)
-{
-  uintptr_t regaddr;
-  uint32_t regval;
-
-  /* Wait until synchronization is complete */
-
-  sam_wait_synchronization(config);
-
-  /* Enable USART module */
-
-  regaddr = config->base + SAM_USART_CTRLA_OFFSET;
-  regval = getreg32(regaddr);
-  regval |= USART_CTRLA_ENABLE;
-  putreg32(regval, regaddr);
-}
-#endif
-
 /****************************************************************************
  * Public Functions
  ****************************************************************************/
@@ -401,7 +373,7 @@ void sam_lowsetup(void)
  ****************************************************************************/
 
 #ifdef SAMD2L2_HAVE_USART
-int sam_usart_initialize(const struct sam_usart_config_s * const config)
+int sam_usart_initialize(const struct sam_usart_config_s *const config)
 {
   irqstate_t flags;
   int ret;
@@ -431,7 +403,7 @@ int sam_usart_initialize(const struct sam_usart_config_s * const config)
  ****************************************************************************/
 
 #ifdef SAMD2L2_HAVE_USART
-void sam_usart_reset(const struct sam_usart_config_s * const config)
+void sam_usart_reset(const struct sam_usart_config_s *const config)
 {
   uintptr_t regaddr = config->base + SAM_USART_CTRLA_OFFSET;
   uint32_t regval;
@@ -451,6 +423,33 @@ void sam_usart_reset(const struct sam_usart_config_s * const config)
 }
 #endif
 
+/****************************************************************************
+ * Name: sam_usart_enable
+ *
+ * Description:
+ *   Enable the SERCOM USART (without enabling interrupts).
+ *
+ ****************************************************************************/
+
+#ifdef SAMD2L2_HAVE_USART
+void sam_usart_enable(const struct sam_usart_config_s *const config)
+{
+  uintptr_t regaddr;
+  uint32_t regval;
+
+  /* Wait until synchronization is complete */
+
+  sam_wait_synchronization(config);
+
+  /* Enable USART module */
+
+  regaddr = config->base + SAM_USART_CTRLA_OFFSET;
+  regval = getreg32(regaddr);
+  regval |= USART_CTRLA_ENABLE;
+  putreg32(regval, regaddr);
+}
+#endif
+
 /****************************************************************************
  * Name: sam_lowputc
  *
diff --git a/arch/arm/src/samd2l2/sam_lowputc.h b/arch/arm/src/samd2l2/sam_lowputc.h
index c51f895bf6..b84fcf3e57 100644
--- a/arch/arm/src/samd2l2/sam_lowputc.h
+++ b/arch/arm/src/samd2l2/sam_lowputc.h
@@ -93,7 +93,7 @@ void sam_lowsetup(void);
 
 #ifdef SAMD2L2_HAVE_USART
 struct sam_usart_config_s;
-int sam_usart_initialize(const struct sam_usart_config_s * const config);
+int sam_usart_initialize(const struct sam_usart_config_s *const config);
 #endif
 
 /****************************************************************************
@@ -107,7 +107,20 @@ int sam_usart_initialize(const struct sam_usart_config_s * const config);
 
 #ifdef SAMD2L2_HAVE_USART
 struct sam_usart_config_s;
-void sam_usart_reset(const struct sam_usart_config_s * const config);
+void sam_usart_reset(const struct sam_usart_config_s *const config);
+#endif
+
+/****************************************************************************
+ * Name: sam_usart_enable
+ *
+ * Description:
+ *   Enable the SERCOM USART (without enabling interrupts).
+ *
+ ****************************************************************************/
+
+#ifdef SAMD2L2_HAVE_USART
+struct sam_usart_config_s;
+void sam_usart_enable(const struct sam_usart_config_s *const config);
 #endif
 
 /****************************************************************************
diff --git a/arch/arm/src/samd2l2/sam_serial.c b/arch/arm/src/samd2l2/sam_serial.c
index 70ee942dba..6ad9b3d31b 100644
--- a/arch/arm/src/samd2l2/sam_serial.c
+++ b/arch/arm/src/samd2l2/sam_serial.c
@@ -666,6 +666,10 @@ static int sam_setup(struct uart_dev_s *dev)
   if (!dev->isconsole)
     {
       ret = sam_usart_initialize(priv->config);
+      if (ret >= 0)
+        {
+          sam_usart_enable(priv->config);
+        }
     }
 #endif
 
diff --git a/include/nuttx/symtab.h b/include/nuttx/symtab.h
index b2cea91348..34e015a80d 100644
--- a/include/nuttx/symtab.h
+++ b/include/nuttx/symtab.h
@@ -137,6 +137,19 @@ FAR const struct symtab_s *
 symtab_findbyvalue(FAR const struct symtab_s *symtab,
                    FAR void *value, int nsyms);
 
+/****************************************************************************
+ * Name: symtab_sortbyname
+ *
+ * Description:
+ *   Sort the symbol table by name.
+ *
+ * Returned Value:
+ *   None.
+ *
+ ****************************************************************************/
+
+void symtab_sortbyname(FAR struct symtab_s *symtab, int nsyms);
+
 #undef EXTERN
 #if defined(__cplusplus)
 }
diff --git a/libs/libc/symtab/Make.defs b/libs/libc/symtab/Make.defs
index 5a7ddab07f..74daa2c73c 100644
--- a/libs/libc/symtab/Make.defs
+++ b/libs/libc/symtab/Make.defs
@@ -36,7 +36,7 @@
 # Symbol table source files
 
 CSRCS += symtab_findbyname.c symtab_findbyvalue.c
-CSRCS += symtab_findorderedbyname.c
+CSRCS += symtab_findorderedbyname.c symtab_sortbyname.c
 
 # Add the symtab directory to the build
 
diff --git a/libs/libc/symtab/symtab_sortbyname.c b/libs/libc/symtab/symtab_sortbyname.c
new file mode 100644
index 0000000000..383fb61b1d
--- /dev/null
+++ b/libs/libc/symtab/symtab_sortbyname.c
@@ -0,0 +1,79 @@
+/****************************************************************************
+ * libs/libc/symtab/symtab_sortbyname.c
+ *
+ *   Copyright (C) 2019 Pinecone Inc. All rights reserved.
+ *   Author: Xiang Xiao <xiaoxiang@pinecone.net>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+
+#include <nuttx/symtab.h>
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+static int symtab_comparename(FAR const void *arg1, FAR const void *arg2)
+{
+  FAR const struct symtab_s *symtab1 = arg1;
+  FAR const struct symtab_s *symtab2 = arg2;
+
+  return strcmp(symtab1->sym_name, symtab2->sym_name);
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: symtab_sortbyname
+ *
+ * Description:
+ *   Sort the symbol table by name.
+ *
+ * Returned Value:
+ *   None.
+ *
+ ****************************************************************************/
+
+void symtab_sortbyname(FAR struct symtab_s *symtab, int nsyms)
+{
+  DEBUGASSERT(symtab != NULL && nsyms != 0);
+  qsort(symtab, nsyms, sizeof(symtab[0]), symtab_comparename);
+}