/****************************************************************************
 * arch/avr/src/avr/up_checkstack.c
 *
 *   Copyright (C) 2011 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/arch.h> 

#include "os_internal.h"

#if defined(CONFIG_DEBUG) && defined(CONFIG_DEBUG_STACK)

/****************************************************************************
 * Private Types
 ****************************************************************************/

/****************************************************************************
 * Private Function Prototypes
 ****************************************************************************/

/****************************************************************************
 * Global Functions
 ****************************************************************************/

/****************************************************************************
 * Name: up_check_stack
 *
 * Description:
 *   Determine (approximately) how much stack has been used be searching the
 *   stack memory for a high water mark.  That is, the deepest level of the
 *   stack that clobbered some recognizable marker in the stack memory.
 *
 * Input Parameters:
 *   None
 *
 * Returned value:
 *   The estimated amount of stack space used.
 *
 ****************************************************************************/

size_t up_check_tcbstack(FAR _TCB *tcb)
{
  FAR uint8_t *ptr;
  size_t mark;
  int i, j;

  /* The AVR uses a push-down stack:  the stack grows toward lower addresses
   * in memory.  We need to start at the lowest address in the stack memory
   * allocation and search to higher addresses.  The first byte we encounter
   * that does not have the magic value is the high water mark.
   */

  for (ptr = (FAR uint8_t *)tcb->stack_alloc_ptr, mark = tcb->adj_stack_size;
       *ptr == 0xaa && mark > 0;
       ptr++, mark--);

  /* If the stack is completely used, then this might mean that the stack
   * overflowed from above (meaning that the stack is too small), or may
   * have been overwritten from below meaning that some other stack or data
   * structure overflowed.
   *
   * If you see returned values saying that the entire stack is being used
   * then enable the following logic to see it there are unused areas in the
   * middle of the stack.
   */

#if 0
  if (mark + 16 > tcb->adj_stack_size)
    {
      ptr = (FAR uint8_t *)tcb->stack_alloc_ptr;
      for (i = 0; i < tcb->adj_stack_size; i += 64)
        {
          for (j = 0; j < 64; j++)
            {
              int ch;
              if (*ptr++ == 0xaa)
                {
                  ch = '.';
                }
              else
                {
                  ch = 'X';
                }
              up_putc(ch);
             }
          up_putc('\n');
        }
     }
#endif

  /* Return our guess about how much stack space was used */

  return mark;
}

size_t up_check_stack(void)
{
  return up_check_tcbstack((FAR _TCB*)g_readytorun.head);
}

#endif /* CONFIG_DEBUG && CONFIG_DEBUG_STACK */
