Add beginning of a simple granule allocator to support DMA IO buffer allocation

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@5129 42af7a65-404d-4744-a932-0658087f49c3

1 files changed, 134 insertions, 0 deletions

diff --git a/nuttx/mm/mm_granfree.c b/nuttx/mm/mm_granfree.c
new file mode 100644
index 000000000..4679ae62b
--- /dev/null
+++ b/nuttx/mm/mm_granfree.c
@@ -0,0 +1,134 @@
+/****************************************************************************
+ * mm/mm_granfree.c
+ *
+ *   Copyright (C) 2012 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
+ *
+ * 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/gran.h>
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: gran_common_free
+ *
+ * Description:
+ *   Return memory to the granule heap.
+ *
+ * Input Parameters:
+ *   handle - The handle previously returned by gran_initialize
+ *   memory - A pointer to memory previoiusly allocated by gran_alloc.
+ *
+ * Returned Value:
+ *   None
+ *
+ ****************************************************************************/
+
+static inline void gran_common_free(FAR struct gran_s *priv,
+                                    FAR void *memory, size_t size)
+{
+  unsigned int granno;
+  unsigned int gatidx;
+  unsigned int gatbit;
+  unsigned int avail;
+  uint32_t mask;
+
+  /* Determine the granule number of the allocation */
+
+  granno = (alloc - priv->heapstart) >> priv->log2gran;
+
+  /* Determine the GAT table index associated with the allocation */
+
+  gatidx = granno >> 5;
+  gatbit = granno & 31;
+
+  /* Clear bits in the first GAT entry */
+
+  avail = 32 - gatbit;
+  if (ngranules > avail)
+    {
+      priv->gat[gatidx] &= ~(0xffffffff << gatbit);
+      ngranules -= avail;
+    }
+
+  /* Handle the cae where where all of the granules came from one entry */
+
+  else
+    {
+      mask = 0xffffffff >> (32 - ngranules);
+      priv->gat[gatidx] &= ~(mask << gatbit);
+      return;
+    }
+
+  /* Clear bits in the second GAT entry */
+
+  mask = 0xffffffff >> (32 - ngranules);
+  priv->gat[gatidx+1] &= ~(mask << gatbit);
+}
+
+/****************************************************************************
+ * Global Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: gran_free
+ *
+ * Description:
+ *   Return memory to the granule heap.
+ *
+ * Input Parameters:
+ *   handle - The handle previously returned by gran_initialize
+ *   memory - A pointer to memory previoiusly allocated by gran_alloc.
+ *
+ * Returned Value:
+ *   None
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_GRAN_SINGLE
+void gran_free(FAR void *memory, size_t size)
+{
+  return gran_common_free(g_graninfo, memory, size);
+}
+#else
+void gran_free(GRAN_HANDLE handle, FAR void *memory, size_t size)
+{
+  return gran_common_free((FAR struct gran_s *)handle, memory, size);
+}
+#endif