Add framework for AVR

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@2961 42af7a65-404d-4744-a932-0658087f49c3

17 files changed, 1890 insertions, 0 deletions

diff --git a/nuttx/arch/avr/src/common/up_allocateheap.c b/nuttx/arch/avr/src/common/up_allocateheap.c
new file mode 100644
index 000000000..62be64338
--- /dev/null
+++ b/nuttx/arch/avr/src/common/up_allocateheap.c
@@ -0,0 +1,83 @@
+/****************************************************************************
+ * arch/avr/src/common/up_allocateheap.c
+ *
+ *   Copyright (C) 2010 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 <sys/types.h>
+#include <debug.h>
+
+#include <nuttx/arch.h>
+#include <arch/board/board.h>
+
+#include "up_arch.h"
+#include "up_internal.h"
+
+/****************************************************************************
+ * Private Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_allocate_heap
+ *
+ * Description:
+ *   The heap may be statically allocated by
+ *   defining CONFIG_HEAP_BASE and CONFIG_HEAP_SIZE.  If these
+ *   are not defined, then this function will be called to
+ *   dynamically set aside the heap region.
+ *
+ ****************************************************************************/
+
+void up_allocate_heap(FAR void **heap_start, size_t *heap_size)
+{
+  up_ledon(LED_HEAPALLOCATE);
+  *heap_start = (FAR void*)g_heapbase;
+  *heap_size = CONFIG_DRAM_END - g_heapbase;
+}
diff --git a/nuttx/arch/avr/src/common/up_arch.h b/nuttx/arch/avr/src/common/up_arch.h
new file mode 100644
index 000000000..16a303c5a
--- /dev/null
+++ b/nuttx/arch/avr/src/common/up_arch.h
@@ -0,0 +1,90 @@
+/****************************************************************************
+ * arch/avr/src/common/up_arch.h
+ *
+ *   Copyright (C) 2010 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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.
+ *
+ ****************************************************************************/
+
+#ifndef __ARCH_AVR_SRC_COMMON_UP_ARCH_H
+#define __ARCH_AVR_SRC_COMMON_UP_ARCH_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+#ifndef __ASSEMBLY__
+# include <stdint.h>
+#endif
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Inline Functions
+ ****************************************************************************/
+
+#ifndef __ASSEMBLY__
+
+# 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))
+
+/****************************************************************************
+ * Public Function Prototypes
+ ****************************************************************************/
+
+#undef EXTERN
+#if defined(__cplusplus)
+#define EXTERN extern "C"
+extern "C" {
+#else
+#define EXTERN extern
+#endif
+
+/* Atomic modification of registers */
+
+EXTERN void modifyreg8(unsigned int addr, uint8_t clearbits, uint8_t setbits);
+EXTERN void modifyreg16(unsigned int addr, uint16_t clearbits, uint16_t setbits);
+EXTERN void modifyreg32(unsigned int addr, uint32_t clearbits, uint32_t setbits);
+
+#undef EXTERN
+#if defined(__cplusplus)
+}
+#endif
+
+#endif /* __ASSEMBLY__ */
+#endif /* __ARCH_AVR_SRC_COMMON_UP_ARCH_H */
+
diff --git a/nuttx/arch/avr/src/common/up_createstack.c b/nuttx/arch/avr/src/common/up_createstack.c
new file mode 100644
index 000000000..7b83357b6
--- /dev/null
+++ b/nuttx/arch/avr/src/common/up_createstack.c
@@ -0,0 +1,138 @@
+/****************************************************************************
+ * arch/avr/src/common/up_createstack.c
+ *
+ *   Copyright (C) 2010 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 <sys/types.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <sched.h>
+#include <debug.h>
+
+#include <nuttx/kmalloc.h>
+#include <nuttx/arch.h>
+#include <arch/board/board.h>
+
+#include "up_arch.h"
+#include "up_internal.h"
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Global Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_create_stack
+ *
+ * Description:
+ *   Allocate a stack for a new thread and setup
+ *   up stack-related information in the TCB.
+ *
+ *   The following TCB fields must be initialized:
+ *   adj_stack_size: Stack size after adjustment for hardware,
+ *     processor, etc.  This value is retained only for debug
+ *     purposes.
+ *   stack_alloc_ptr: Pointer to allocated stack
+ *   adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The
+ *     initial value of the stack pointer.
+ *
+ * Inputs:
+ *   tcb: The TCB of new task
+ *   stack_size:  The requested stack size.  At least this much
+ *     must be allocated.
+ ****************************************************************************/
+
+int up_create_stack(_TCB *tcb, size_t stack_size)
+{
+  if (tcb->stack_alloc_ptr &&
+      tcb->adj_stack_size != stack_size)
+    {
+      sched_free(tcb->stack_alloc_ptr);
+      tcb->stack_alloc_ptr = NULL;
+    }
+
+   if (!tcb->stack_alloc_ptr)
+     {
+#ifdef CONFIG_DEBUG
+       tcb->stack_alloc_ptr = (uint32_t*)zalloc(stack_size);
+#else
+       tcb->stack_alloc_ptr = (uint32_t*)malloc(stack_size);
+#endif
+     }
+
+   if (tcb->stack_alloc_ptr)
+     {
+       size_t top_of_stack;
+       size_t size_of_stack;
+
+       /* The AVR32 uses a push-down stack:  the stack grows
+	* toward loweraddresses in memory.  The stack pointer
+	* register, points to the lowest, valid work address
+	* (the "top" of the stack).  Items on the stack are
+	* referenced as positive word offsets from sp.
+	*/
+
+       top_of_stack = (uint32_t)tcb->stack_alloc_ptr + stack_size - 4;
+
+       /* The AVR32 stack must be aligned at word (4 byte)
+	* boundaries. If necessary top_of_stack must be rounded
+	* down to the next boundary
+	*/
+
+       top_of_stack &= ~3;
+       size_of_stack = top_of_stack - (uint32_t)tcb->stack_alloc_ptr + 4;
+
+       /* Save the adjusted stack values in the _TCB */
+
+       tcb->adj_stack_ptr  = (uint32_t*)top_of_stack;
+       tcb->adj_stack_size = size_of_stack;
+
+       up_ledon(LED_STACKCREATED);
+       return OK;
+     }
+
+   return ERROR;
+}
diff --git a/nuttx/arch/avr/src/common/up_exit.c b/nuttx/arch/avr/src/common/up_exit.c
new file mode 100644
index 000000000..d7104c5da
--- /dev/null
+++ b/nuttx/arch/avr/src/common/up_exit.c
@@ -0,0 +1,174 @@
+/****************************************************************************
+ * arch/avr/src/common/up_exit.c
+ *
+ *   Copyright (C) 2010 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 <sched.h>
+#include <debug.h>
+#include <nuttx/arch.h>
+
+#include "os_internal.h"
+#include "up_internal.h"
+
+#ifdef CONFIG_DUMP_ON_EXIT
+#include <nuttx/fs.h>
+#endif
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: _up_dumponexit
+ *
+ * Description:
+ *   Dump the state of all tasks whenever on task exits.  This is debug
+ *   instrumentation that was added to check file-related reference counting
+ *   but could be useful again sometime in the future.
+ *
+ ****************************************************************************/
+
+#if defined(CONFIG_DUMP_ON_EXIT) && defined(CONFIG_DEBUG)
+static void _up_dumponexit(FAR _TCB *tcb, FAR void *arg)
+{
+#if CONFIG_NFILE_DESCRIPTORS > 0 || CONFIG_NFILE_STREAMS > 0
+  int i;
+#endif
+
+  sdbg("  TCB=%p name=%s pid=%d\n", tcb, tcb->argv[0], tcb->pid);
+  sdbg("    priority=%d state=%d\n", tcb->sched_priority, tcb->task_state);
+
+#if CONFIG_NFILE_DESCRIPTORS > 0
+  if (tcb->filelist)
+    {
+      sdbg("    filelist refcount=%d\n",
+           tcb->filelist->fl_crefs);
+
+      for (i = 0; i < CONFIG_NFILE_DESCRIPTORS; i++)
+        {
+          struct inode *inode = tcb->filelist->fl_files[i].f_inode;
+          if (inode)
+            {
+              sdbg("      fd=%d refcount=%d\n",
+                   i, inode->i_crefs);
+            }
+        }
+    }
+#endif
+
+#if CONFIG_NFILE_STREAMS > 0
+  if (tcb->streams)
+    {
+      sdbg("    streamlist refcount=%d\n",
+           tcb->streams->sl_crefs);
+
+      for (i = 0; i < CONFIG_NFILE_STREAMS; i++)
+        {
+          struct file_struct *filep = &tcb->streams->sl_streams[i];
+          if (filep->fs_filedes >= 0)
+            {
+#if CONFIG_STDIO_BUFFER_SIZE > 0
+              sdbg("      fd=%d nbytes=%d\n",
+                   filep->fs_filedes,
+                  filep->fs_bufpos - filep->fs_bufstart);
+#else
+              sdbg("      fd=%d\n", filep->fs_filedes);
+#endif
+            }
+        }
+    }
+#endif
+}
+#endif
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: _exit
+ *
+ * Description:
+ *   This function causes the currently executing task to cease
+ *   to exist.  This is a special case of task_delete() where the task to
+ *   be deleted is the currently executing task.  It is more complex because
+ *   a context switch must be perform to the next ready to run task.
+ *
+ ****************************************************************************/
+
+void _exit(int status)
+{
+  _TCB* tcb;
+
+  /* Disable interrupts.  They will be restored when the next
+   * task is started.
+   */
+
+  (void)irqsave();
+
+  slldbg("TCB=%p exitting\n", g_readytorun.head);
+
+#if defined(CONFIG_DUMP_ON_EXIT) && defined(CONFIG_DEBUG)
+  slldbg("Other tasks:\n");
+  sched_foreach(_up_dumponexit, NULL);
+#endif
+
+  /* Destroy the task at the head of the ready to run list. */
+
+  (void)task_deletecurrent();
+
+  /* Now, perform the context switch to the new ready-to-run task at the
+   * head of the list.
+   */
+
+  tcb = (_TCB*)g_readytorun.head;
+
+  /* Then switch contexts */
+
+  up_fullcontextrestore(tcb->xcp.regs);
+}
+
diff --git a/nuttx/arch/avr/src/common/up_idle.c b/nuttx/arch/avr/src/common/up_idle.c
new file mode 100644
index 000000000..2854956cd
--- /dev/null
+++ b/nuttx/arch/avr/src/common/up_idle.c
@@ -0,0 +1,87 @@
+/****************************************************************************
+ *  arch/avr/src/common/up_idle.c
+ *
+ *   Copyright (C) 2010 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 <nuttx/arch.h>
+#include "up_internal.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_idle
+ *
+ * Description:
+ *   up_idle() is the logic that will be executed when their
+ *   is no other ready-to-run task.  This is processor idle
+ *   time and will continue until some interrupt occurs to
+ *   cause a context switch from the idle task.
+ *
+ *   Processing in this state may be processor-specific. e.g.,
+ *   this is where power management operations might be
+ *   performed.
+ *
+ ****************************************************************************/
+
+void up_idle(void)
+{
+#if defined(CONFIG_SUPPRESS_INTERRUPTS) || defined(CONFIG_SUPPRESS_TIMER_INTS)
+  /* If the system is idle and there are no timer interrupts,
+   * then process "fake" timer interrupts. Hopefully, something
+   * will wake up.
+   */
+
+  sched_process_timer();
+#endif
+}
+
diff --git a/nuttx/arch/avr/src/common/up_initialize.c b/nuttx/arch/avr/src/common/up_initialize.c
new file mode 100644
index 000000000..fde474ec6
--- /dev/null
+++ b/nuttx/arch/avr/src/common/up_initialize.c
@@ -0,0 +1,170 @@
+/****************************************************************************
+ * arch/avr/src/common/up_initialize.c
+ *
+ *   Copyright (C) 2010 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 <debug.h>
+
+#include <nuttx/arch.h>
+#include <nuttx/fs.h>
+#include <arch/board/board.h>
+
+#include "up_arch.h"
+#include "up_internal.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_calibratedelay
+ *
+ * Description:
+ *   Delay loops are provided for short timing loops.  This function, if
+ *   enabled, will just wait for 100 seconds.  Using a stopwatch, you can
+ *   can then determine if the timing loops are properly calibrated.
+ *
+ ****************************************************************************/
+
+#if defined(CONFIG_ARCH_CALIBRATION) && defined(CONFIG_DEBUG)
+static void up_calibratedelay(void)
+{
+  int i;
+  lldbg("Beginning 100s delay\n");
+  for (i = 0; i < 100; i++)
+    {
+      up_mdelay(1000);
+    }
+  lldbg("End 100s delay\n");
+}
+#else
+# define up_calibratedelay()
+#endif
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_initialize
+ *
+ * Description:
+ *   up_initialize will be called once during OS initialization after the
+ *   basic OS services have been initialized.  The architecture specific
+ *   details of initializing the OS will be handled here.  Such things as
+ *   setting up interrupt service routines, starting the clock, and
+ *   registering device drivers are some of the things that are different
+ *   for each processor and hardware platform.
+ *
+ *   up_initialize is called after the OS initialized but before the user
+ *   initialization logic has been started and before the libraries have
+ *   been initialized.  OS services and driver services are available.
+ *
+ ****************************************************************************/
+
+void up_initialize(void)
+{
+  /* Initialize global variables */
+
+  current_regs = NULL;
+
+  /* Calibrate the timing loop */
+
+  up_calibratedelay();
+
+  /* Add any extra memory fragments to the memory manager */
+
+  up_addregion();
+
+  /* Initialize the interrupt subsystem */
+
+  up_irqinitialize();
+
+  /* Initialize the DMA subsystem if the weak function stm32_dmainitialize has been
+   * brought into the build
+   */
+
+#ifdef CONFIG_ARCH_DMA
+#ifdef CONFIG_HAVE_WEAKFUNCTIONS
+  if (up_dmainitialize)
+#endif
+    {
+      up_dmainitialize();
+    }
+#endif
+
+  /* Initialize the system timer interrupt */
+
+#if !defined(CONFIG_SUPPRESS_INTERRUPTS) && !defined(CONFIG_SUPPRESS_TIMER_INTS)
+  up_timerinit();
+#endif
+
+  /* Register devices */
+
+#if CONFIG_NFILE_DESCRIPTORS > 0
+  devnull_register();   /* Standard /dev/null */
+#endif
+
+  /* Initialize the serial device driver */
+
+#ifdef CONFIG_USE_SERIALDRIVER
+  up_serialinit();
+#elif defined(CONFIG_DEV_LOWCONSOLE)
+  lowconsole_init();
+#endif
+
+  /* Initialize the netwok */
+
+  up_netinitialize();
+
+  /* Initialize USB */
+
+  up_usbinitialize();
+
+  up_ledon(LED_IRQSENABLED);
+}
+
diff --git a/nuttx/arch/avr/src/common/up_internal.h b/nuttx/arch/avr/src/common/up_internal.h
new file mode 100644
index 000000000..2468326ee
--- /dev/null
+++ b/nuttx/arch/avr/src/common/up_internal.h
@@ -0,0 +1,245 @@
+/****************************************************************************
+ * arch/avr/src/common/up_internal.h
+ *
+ *   Copyright (C) 2010 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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.
+ *
+ ****************************************************************************/
+
+#ifndef __UP_INTERNAL_H
+#define __UP_INTERNAL_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#ifndef __ASSEMBLY__
+#  include <stdint.h>
+#endif
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/* Bring-up debug configurations.  These are here (vs defconfig)
+ * because these should only be controlled during low level
+ * board bring-up and not part of normal platform configuration.
+ */
+
+#undef  CONFIG_SUPPRESS_INTERRUPTS    /* DEFINED: Do not enable interrupts */
+#undef  CONFIG_SUPPRESS_TIMER_INTS    /* DEFINED: No timer */
+#undef  CONFIG_SUPPRESS_SERIAL_INTS   /* DEFINED: Console will poll */
+#undef  CONFIG_SUPPRESS_UART_CONFIG   /* DEFINED: Do not reconfig UART */
+#undef  CONFIG_DUMP_ON_EXIT           /* DEFINED: Dump task state on exit */
+
+/* Determine which (if any) console driver to use */
+
+#if CONFIG_NFILE_DESCRIPTORS == 0 || defined(CONFIG_DEV_LOWCONSOLE)
+#  undef CONFIG_USE_SERIALDRIVER
+#  undef CONFIG_USE_EARLYSERIALINIT
+#elif defined(CONFIG_DEV_CONSOLE) && CONFIG_NFILE_DESCRIPTORS > 0
+#  define CONFIG_USE_SERIALDRIVER 1
+#  define CONFIG_USE_EARLYSERIALINIT 1
+#endif
+
+/* Check if an interrupt stack size is configured */
+
+#ifndef CONFIG_ARCH_INTERRUPTSTACK
+# define CONFIG_ARCH_INTERRUPTSTACK 0
+#endif
+
+/* Macros to handle saving and restore interrupt state.  The state is copied
+ * from the stack to the TCB, but only a referenced is passed to get the 
+ * state from the TCB.
+ */
+
+#define up_savestate(regs)    up_copystate(regs, current_regs)
+#define up_restorestate(regs) (current_regs = regs)
+
+/****************************************************************************
+ * Public Types
+ ****************************************************************************/
+
+#ifndef __ASSEMBLY__
+typedef void (*up_vector_t)(void);
+#endif
+
+/****************************************************************************
+ * Public Variables
+ ****************************************************************************/
+
+#ifndef __ASSEMBLY__
+/* This holds a references to the current interrupt level
+ * register storage structure.  If is non-NULL only during
+ * interrupt processing.
+ */
+
+extern uint32_t *current_regs;
+
+/* This is the beginning of heap as provided from up_head.S.
+ * This is the first address in DRAM after the loaded
+ * program+bss+idle stack.  The end of the heap is
+ * CONFIG_DRAM_END
+ */
+
+extern uint32_t g_heapbase;
+
+/* Address of the saved user stack pointer */
+
+#if CONFIG_ARCH_INTERRUPTSTACK > 3
+extern void g_intstackbase;
+#endif
+
+/* These 'addresses' of these values are setup by the linker script.  They are
+ * not actual uint32_t storage locations! They are only used meaningfully in the
+ * following way:
+ *
+ *  - The linker script defines, for example, the symbol_sdata.
+ *  - The declareion extern uint32_t _sdata; makes C happy.  C will believe
+ *    that the value _sdata is the address of a uint32_t variable _data (it is
+ *    not!).
+ *  - We can recoved the linker value then by simply taking the address of
+ *    of _data.  like:  uint32_t *pdata = &_sdata;
+ */
+
+extern uint32_t _stext;           /* Start of .text */
+extern uint32_t _etext;           /* End_1 of .text + .rodata */
+extern const uint32_t _eronly;    /* End+1 of read only section (.text + .rodata) */
+extern uint32_t _sdata;           /* Start of .data */
+extern uint32_t _edata;           /* End+1 of .data */
+extern uint32_t _sbss;            /* Start of .bss */
+extern uint32_t _ebss;            /* End+1 of .bss */
+#endif
+
+/****************************************************************************
+ * Inline Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+#ifndef __ASSEMBLY__
+
+/* Defined in files with the same name as the function */
+
+extern void up_boot(void);
+extern void up_copystate(uint32_t *dest, uint32_t *src);
+extern void up_decodeirq(uint32_t *regs);
+extern void up_irqinitialize(void);
+#ifdef CONFIG_ARCH_DMA
+extern void weak_function up_dmainitialize(void);
+#endif
+extern int  up_saveusercontext(uint32_t *saveregs);
+extern void up_fullcontextrestore(uint32_t *restoreregs) __attribute__ ((noreturn));
+extern void up_switchcontext(uint32_t *saveregs, uint32_t *restoreregs);
+extern void up_sigdeliver(void);
+extern int  up_timerisr(int irq, uint32_t *regs);
+extern void up_lowputc(char ch);
+extern void up_puts(const char *str);
+extern void up_lowputs(const char *str);
+extern uint32_t *up_doirq(int irq, uint32_t *regs);
+extern int  up_svcall(int irq, FAR void *context);
+extern int  up_hardfault(int irq, FAR void *context);
+#ifdef CONFIG_PAGING
+extern void up_pginitialize(void);
+extern uint32_t *up_va2pte(uintptr_t vaddr);
+#else /* CONFIG_PAGING */
+# define up_pginitialize()
+#endif /* CONFIG_PAGING */
+
+/* Defined in up_allocateheap.c */
+
+#if CONFIG_MM_REGIONS > 1
+void up_addregion(void);
+#else
+# define up_addregion()
+#endif
+
+/* Defined in up_serial.c */
+
+#if CONFIG_NFILE_DESCRIPTORS > 0
+extern void up_earlyserialinit(void);
+extern void up_serialinit(void);
+#else
+# define up_earlyserialinit()
+# define up_serialinit()
+#endif
+
+/* Defined in drivers/lowconsole.c */
+
+#ifdef CONFIG_DEV_LOWCONSOLE
+extern void lowconsole_init(void);
+#else
+# define lowconsole_init()
+#endif
+
+/* Defined in up_timerisr.c */
+
+extern void up_timerinit(void);
+
+/* Defined in up_irq.c */
+
+extern void up_maskack_irq(int irq);
+
+/* Defined in board/up_leds.c */
+
+#ifdef CONFIG_ARCH_LEDS
+extern void up_ledinit(void);
+extern void up_ledon(int led);
+extern void up_ledoff(int led);
+#else
+# define up_ledinit()
+# define up_ledon(led)
+# define up_ledoff(led)
+#endif
+
+/* Defined in board/up_network.c */
+
+#ifdef CONFIG_NET
+extern void up_netinitialize(void);
+#else
+# define up_netinitialize()
+#endif
+
+/* Defined in board/up_ethernet.c */
+
+#ifdef CONFIG_USBDEV
+extern void up_usbinitialize(void);
+extern void up_usbuninitialize(void);
+#else
+# define up_usbinitialize()
+# define up_usbuninitialize()
+#endif
+
+#endif /* __ASSEMBLY__ */
+
+#endif  /* __UP_INTERNAL_H */
+
diff --git a/nuttx/arch/avr/src/common/up_interruptcontext.c b/nuttx/arch/avr/src/common/up_interruptcontext.c
new file mode 100644
index 000000000..c1bfb0e4d
--- /dev/null
+++ b/nuttx/arch/avr/src/common/up_interruptcontext.c
@@ -0,0 +1,70 @@
+/****************************************************************************
+ *  arch/avr/src/common/up_interruptcontext.c
+ *
+ *   Copyright (C) 2010 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 <stdbool.h>
+#include <nuttx/arch.h>
+#include <nuttx/irq.h>
+
+#include "up_internal.h"
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Global Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_interrupt_context
+ *
+ * Description: Return true is we are currently executing in
+ * the interrupt handler context.
+ ****************************************************************************/
+
+bool up_interrupt_context(void)
+{
+   return current_regs != NULL;
+}
diff --git a/nuttx/arch/avr/src/common/up_lowputs.c b/nuttx/arch/avr/src/common/up_lowputs.c
new file mode 100644
index 000000000..5695b806a
--- /dev/null
+++ b/nuttx/arch/avr/src/common/up_lowputs.c
@@ -0,0 +1,75 @@
+/****************************************************************************
+ * arch/avr/src/common/up_lowputs.c
+ *
+ *   Copyright (C) 2010 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 "up_internal.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_lowputs
+ *
+ * Description:
+ *   This is a low-level helper function used to support debug.
+ *
+ ****************************************************************************/
+
+void up_lowputs(const char *str)
+{
+  while(*str)
+    {
+      up_lowputc(*str++);
+    }
+}
+
diff --git a/nuttx/arch/avr/src/common/up_mdelay.c b/nuttx/arch/avr/src/common/up_mdelay.c
new file mode 100644
index 000000000..3fb76a058
--- /dev/null
+++ b/nuttx/arch/avr/src/common/up_mdelay.c
@@ -0,0 +1,91 @@
+/****************************************************************************
+ *  arch/avr/src/common/up_mdelay.c
+ *
+ *   Copyright (C) 2010 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 <nuttx/arch.h>
+
+/****************************************************************************
+ * Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Variables
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_mdelay
+ *
+ * Description:
+ *   Delay inline for the requested number of milliseconds.
+ *   *** NOT multi-tasking friendly ***
+ *
+ * ASSUMPTIONS:
+ *   The setting CONFIG_BOARD_LOOPSPERMSEC has been calibrated
+ *
+ ****************************************************************************/
+
+void up_mdelay(unsigned int milliseconds)
+{
+  volatile int i;
+  volatile int j;
+
+  for (i = 0; i < milliseconds; i++)
+    {
+        for (j = 0; j < CONFIG_BOARD_LOOPSPERMSEC; j++)
+          {
+          }
+    }
+}
+
diff --git a/nuttx/arch/avr/src/common/up_modifyreg16.c b/nuttx/arch/avr/src/common/up_modifyreg16.c
new file mode 100644
index 000000000..e06f91f96
--- /dev/null
+++ b/nuttx/arch/avr/src/common/up_modifyreg16.c
@@ -0,0 +1,86 @@
+/****************************************************************************
+ * arch/avr/src/common/up_modifyreg16.c
+ *
+ *   Copyright (C) 2010 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 <stdint.h>
+#include <debug.h>
+
+#include <arch/irq.h>
+#include <nuttx/arch.h>
+
+#include "up_arch.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: modifyreg16
+ *
+ * Description:
+ *   Atomically modify the specified bits in a memory mapped register
+ *
+ ****************************************************************************/
+
+void modifyreg16(unsigned int addr, uint16_t clearbits, uint16_t setbits)
+{
+  irqstate_t flags;
+  uint16_t   regval;
+
+  flags   = irqsave();
+  regval  = getreg16(addr);
+  regval &= ~clearbits;
+  regval |= setbits;
+  putreg16(regval, addr);
+  irqrestore(flags);
+}
+
diff --git a/nuttx/arch/avr/src/common/up_modifyreg32.c b/nuttx/arch/avr/src/common/up_modifyreg32.c
new file mode 100644
index 000000000..3369abb56
--- /dev/null
+++ b/nuttx/arch/avr/src/common/up_modifyreg32.c
@@ -0,0 +1,86 @@
+/****************************************************************************
+ * arch/avr/src/common/up_modifyreg32.c
+ *
+ *   Copyright (C) 2010 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 <stdint.h>
+#include <debug.h>
+
+#include <arch/irq.h>
+#include <nuttx/arch.h>
+
+#include "up_arch.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: modifyreg32
+ *
+ * Description:
+ *   Atomically modify the specified bits in a memory mapped register
+ *
+ ****************************************************************************/
+
+void modifyreg32(unsigned int addr, uint32_t clearbits, uint32_t setbits)
+{
+  irqstate_t flags;
+  uint32_t   regval;
+
+  flags   = irqsave();
+  regval  = getreg32(addr);
+  regval &= ~clearbits;
+  regval |= setbits;
+  putreg32(regval, addr);
+  irqrestore(flags);
+}
+
diff --git a/nuttx/arch/avr/src/common/up_modifyreg8.c b/nuttx/arch/avr/src/common/up_modifyreg8.c
new file mode 100644
index 000000000..35537a4ab
--- /dev/null
+++ b/nuttx/arch/avr/src/common/up_modifyreg8.c
@@ -0,0 +1,86 @@
+/****************************************************************************
+ * arch/avr/src/common/up_modifyreg8.c
+ *
+ *   Copyright (C) 2010 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 <stdint.h>
+#include <debug.h>
+
+#include <arch/irq.h>
+#include <nuttx/arch.h>
+
+#include "up_arch.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: modifyreg8
+ *
+ * Description:
+ *   Atomically modify the specified bits in a memory mapped register
+ *
+ ****************************************************************************/
+
+void modifyreg8(unsigned int addr, uint8_t clearbits, uint8_t setbits)
+{
+  irqstate_t flags;
+  uint8_t    regval;
+
+  flags   = irqsave();
+  regval  = getreg8(addr);
+  regval &= ~clearbits;
+  regval |= setbits;
+  putreg8(regval, addr);
+  irqrestore(flags);
+}
+
diff --git a/nuttx/arch/avr/src/common/up_puts.c b/nuttx/arch/avr/src/common/up_puts.c
new file mode 100644
index 000000000..aa651e294
--- /dev/null
+++ b/nuttx/arch/avr/src/common/up_puts.c
@@ -0,0 +1,76 @@
+/****************************************************************************
+ * arch/avr/src/common/up_puts.c
+ *
+ *   Copyright (C) 2010 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 <nuttx/arch.h>
+
+#include "up_internal.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_puts
+ *
+ * Description:
+ *   This is a low-level helper function used to support debug.
+ *
+ ****************************************************************************/
+
+void up_puts(const char *str)
+{
+  while(*str)
+    {
+      up_putc(*str++);
+    }
+}
+
diff --git a/nuttx/arch/avr/src/common/up_releasestack.c b/nuttx/arch/avr/src/common/up_releasestack.c
new file mode 100644
index 000000000..4c453c590
--- /dev/null
+++ b/nuttx/arch/avr/src/common/up_releasestack.c
@@ -0,0 +1,80 @@
+/****************************************************************************
+ *  arch/avr/src/common/up_releasestack.c
+ *
+ *   Copyright (C) 2010 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 <sched.h>
+#include <debug.h>
+#include <nuttx/arch.h>
+
+#include "os_internal.h"
+#include "up_internal.h"
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Global Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_release_stack
+ *
+ * Description:
+ *   A task has been stopped. Free all stack
+ *   related resources retained int the defunct TCB.
+ *
+ ****************************************************************************/
+
+void up_release_stack(_TCB *dtcb)
+{
+  if (dtcb->stack_alloc_ptr)
+    {
+      sched_free(dtcb->stack_alloc_ptr);
+      dtcb->stack_alloc_ptr = NULL;
+    }
+
+  dtcb->adj_stack_size = 0;
+}
+
diff --git a/nuttx/arch/avr/src/common/up_udelay.c b/nuttx/arch/avr/src/common/up_udelay.c
new file mode 100644
index 000000000..5bbeed907
--- /dev/null
+++ b/nuttx/arch/avr/src/common/up_udelay.c
@@ -0,0 +1,130 @@
+/****************************************************************************
+ *  arch/avr/src/common/up_udelay.c
+ *
+ *   Copyright (C) 2010 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 <sys/types.h>
+#include <nuttx/arch.h>
+
+/****************************************************************************
+ * Definitions
+ ****************************************************************************/
+
+#define CONFIG_BOARD_LOOPSPER100USEC ((CONFIG_BOARD_LOOPSPERMSEC+5)/10)
+#define CONFIG_BOARD_LOOPSPER10USEC  ((CONFIG_BOARD_LOOPSPERMSEC+50)/100)
+#define CONFIG_BOARD_LOOPSPERUSEC    ((CONFIG_BOARD_LOOPSPERMSEC+500)/1000)
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Variables
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_udelay
+ *
+ * Description:
+ *   Delay inline for the requested number of microseconds.  NOTE:  Because
+ *   of all of the setup, several microseconds will be lost before the actual
+ *   timing looop begins.  Thus, the delay will always be a few microseconds
+ *   longer than requested.
+ *
+ *   *** NOT multi-tasking friendly ***
+ *
+ * ASSUMPTIONS:
+ *   The setting CONFIG_BOARD_LOOPSPERMSEC has been calibrated
+ *
+ ****************************************************************************/
+
+void up_udelay(useconds_t microseconds)
+{
+  volatile int i;
+
+  /* We'll do this a little at a time because we expect that the
+   * CONFIG_BOARD_LOOPSPERUSEC is very inaccurate during to truncation in
+   * the divisions of its calculation.  We'll use the largest values that
+   * we can in order to prevent significant error buildup in the loops.
+   */
+
+  while (microseconds > 1000)
+    {
+      for (i = 0; i < CONFIG_BOARD_LOOPSPERMSEC; i++)
+        {
+        }
+      microseconds -= 1000;
+    }
+
+  while (microseconds > 100)
+    {
+      for (i = 0; i < CONFIG_BOARD_LOOPSPER100USEC; i++)
+        {
+        }
+      microseconds -= 100;
+    }
+
+  while (microseconds > 10)
+    {
+      for (i = 0; i < CONFIG_BOARD_LOOPSPER10USEC; i++)
+        {
+        }
+      microseconds -= 10;
+    }
+
+  while (microseconds > 0)
+    {
+      for (i = 0; i < CONFIG_BOARD_LOOPSPERUSEC; i++)
+        {
+        }
+      microseconds--;
+    }
+}
+
diff --git a/nuttx/arch/avr/src/common/up_usestack.c b/nuttx/arch/avr/src/common/up_usestack.c
new file mode 100644
index 000000000..b2da00cf2
--- /dev/null
+++ b/nuttx/arch/avr/src/common/up_usestack.c
@@ -0,0 +1,123 @@
+/****************************************************************************
+ * arch/avr/src/common/up_usestack.c
+ *
+ *   Copyright (C) 2010 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 <sys/types.h>
+#include <stdint.h>
+#include <sched.h>
+#include <debug.h>
+
+#include <nuttx/kmalloc.h>
+#include <nuttx/arch.h>
+
+#include "up_internal.h"
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Global Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_use_stack
+ *
+ * Description:
+ *   Setup up stack-related information in the TCB
+ *   using pre-allocated stack memory
+ *
+ *   The following TCB fields must be initialized:
+ *   adj_stack_size: Stack size after adjustment for hardware,
+ *     processor, etc.  This value is retained only for debug
+ *     purposes.
+ *   stack_alloc_ptr: Pointer to allocated stack
+ *   adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The
+ *     initial value of the stack pointer.
+ *
+ * Inputs:
+ *   tcb: The TCB of new task
+ *   stack_size:  The allocated stack size.
+ *
+ ****************************************************************************/
+
+int up_use_stack(_TCB *tcb, void *stack, size_t stack_size)
+{
+  size_t top_of_stack;
+  size_t size_of_stack;
+
+  if (tcb->stack_alloc_ptr)
+    {
+      sched_free(tcb->stack_alloc_ptr);
+    }
+
+  /* Save the stack allocation */
+
+  tcb->stack_alloc_ptr = stack;
+
+  /* The AVR32 uses a push-down stack:  the stack grows
+   * toward loweraddresses in memory.  The stack pointer
+   * register, points to the lowest, valid work address
+   * (the "top" of the stack).  Items on the stack are
+   * referenced as positive word offsets from sp.
+   */
+
+  top_of_stack = (uint32_t)tcb->stack_alloc_ptr + stack_size - 4;
+
+  /* The AVR32 stack must be aligned at word (4 byte)
+   * boundaries. If necessary top_of_stack must be rounded
+   * down to the next boundary
+   */
+
+  top_of_stack &= ~3;
+  size_of_stack = top_of_stack - (uint32_t)tcb->stack_alloc_ptr + 4;
+
+  /* Save the adjusted stack values in the _TCB */
+
+  tcb->adj_stack_ptr  = (uint32_t*)top_of_stack;
+  tcb->adj_stack_size = size_of_stack;
+
+  return OK;
+}
+