NuttX RTOS

git-svn-id: https://nuttx.svn.sourceforge.net/svnroot/nuttx/trunk@3 7fd9a85b-ad96-42d3-883c-3090e2eb8679

1 files changed, 145 insertions, 0 deletions

diff --git a/nuttx/mm/mm_initialize.c b/nuttx/mm/mm_initialize.c
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+/************************************************************
+ * mm_initialize.c
+ *
+ *   Copyright (C) 2007 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 Gregory Nutt 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 "mm_environment.h"
+#include "mm_internal.h"
+
+/************************************************************
+ * Definitions
+ ************************************************************/
+
+/************************************************************
+ * Public Variables
+ ************************************************************/
+
+/* This is the size of the heap provided to mm */
+
+uint32  g_heapsize;
+
+/* This is the first and last nodes of the heap */
+
+struct mm_allocnode_s *g_heapstart;
+struct mm_allocnode_s *g_heapend;
+
+/* All free nodes are maintained in a doubly linked list.  This
+ * array provides some hooks into the list at various points to
+ * speed searches for free nodes.
+ */
+
+struct mm_freenode_s g_nodelist[MM_NNODES];
+
+/************************************************************
+ * Public Functions
+ ************************************************************/
+
+/************************************************************
+ * Function:  mm_initialize
+ *
+ * Description:
+ *   This is an internal OS function called only at power-up
+ *   boot time.
+ *
+ * Parameters:
+ *   None
+ *
+ * Return Value:
+ *   None
+ *
+ * Assumptions:
+ *
+ ************************************************************/
+
+void mm_initialize(void *heapstart, size_t heapsize)
+{
+  struct mm_freenode_s *node;
+  int i;
+
+  CHECK_ALLOCNODE_SIZE;
+  CHECK_FREENODE_SIZE;
+
+  /* Adjust the provide heap start and size so that they are
+   * both aligned with the MM_MIN_CHUNK size.
+   */
+
+  uint32 heapbase = MM_ALIGN_UP((uint32)heapstart);
+  uint32 heapend  = MM_ALIGN_DOWN((uint32)heapstart + (uint32)heapsize);
+
+  /* Save the size of the heap */
+
+  g_heapsize = heapend - heapbase;
+
+  /* Initialize the node array */
+
+  memset(g_nodelist, 0, sizeof(struct mm_freenode_s) * MM_NNODES);
+  for (i = 1; i < MM_NNODES; i++)
+    {
+      g_nodelist[i-1].flink = &g_nodelist[i];
+      g_nodelist[i].blink   = &g_nodelist[i-1];
+    }
+
+  /* Create two "allocated" guard nodes at the beginning and end of
+   * the heap.  These only serve to keep us from allocating outside
+   * of the heap.
+   * 
+   * And create one free node between the guard nodes that contains
+   * all available memory.
+   */
+
+  g_heapstart            = (struct mm_allocnode_s *)heapbase;
+  g_heapstart->size      = SIZEOF_MM_ALLOCNODE;
+  g_heapstart->preceding = MM_ALLOC_BIT;
+
+  node                   = (struct mm_freenode_s *)(heapbase + SIZEOF_MM_ALLOCNODE);
+  node->size             = g_heapsize - 2*SIZEOF_MM_ALLOCNODE;
+  node->preceding        = SIZEOF_MM_ALLOCNODE;
+
+  g_heapend              = (struct mm_allocnode_s *)(heapend - SIZEOF_MM_ALLOCNODE);
+  g_heapend->size        = SIZEOF_MM_ALLOCNODE;
+  g_heapend->preceding   = node->size | MM_ALLOC_BIT;
+
+  /* Add the single, large free node to the nodelist */
+
+  mm_addfreechunk(node);
+
+  /* Initialize the malloc semaphore to one (to support one-at-
+   * a-time access to private data sets.
+   */
+
+  mm_seminitialize();
+}