Add RAM disk supportnuttx-3.11

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@765 42af7a65-404d-4744-a932-0658087f49c3

1 files changed, 250 insertions, 0 deletions

diff --git a/nuttx/drivers/ramdisk.c b/nuttx/drivers/ramdisk.c
new file mode 100644
index 000000000..506eb4593
--- /dev/null
+++ b/nuttx/drivers/ramdisk.c
@@ -0,0 +1,250 @@
+/****************************************************************************
+ * drivers/ramdisk.c
+ *
+ *   Copyright (C) 2008 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 <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+#include <nuttx/fs.h>
+#include <nuttx/ramdisk.h>
+
+/****************************************************************************
+ * Private Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+struct rd_struct_s
+{
+  uint32  rd_nsectors;     /* Number of sectors on device */
+  uint16  rd_sectsize;     /* The size of one sector */
+  boolean rd_writeenabled; /* TRUE: can write to ram disk */
+  ubyte  *rd_buffer;       /* RAM disk backup memory */
+};
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+static int     rd_open(FAR struct inode *inode);
+static int     rd_close(FAR struct inode *inode);
+static ssize_t rd_read(FAR struct inode *inode, unsigned char *buffer,
+                       size_t start_sector, unsigned int nsectors);
+static ssize_t rd_write(FAR struct inode *inode, const unsigned char *buffer,
+                        size_t start_sector, unsigned int nsectors);
+static int     rd_geometry(FAR struct inode *inode, struct geometry *geometry);
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+static const struct block_operations g_bops =
+{
+  rd_open,     /* open     */
+  rd_close,    /* close    */
+  rd_read,     /* read     */
+  rd_write,    /* write    */
+  rd_geometry, /* geometry */
+  NULL         /* ioctl    */
+};
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: rd_open
+ *
+ * Description: Open the block device
+ *
+ ****************************************************************************/
+
+static int rd_open(FAR struct inode *inode)
+{
+  return OK;
+}
+
+/****************************************************************************
+ * Name: rd_closel
+ *
+ * Description: close the block device
+ *
+ ****************************************************************************/
+
+static int rd_close(FAR struct inode *inode)
+{
+  return OK;
+}
+
+/****************************************************************************
+ * Name: rd_read
+ *
+ * Description:  Read the specified numer of sectors
+ *
+ ****************************************************************************/
+
+static ssize_t rd_read(FAR struct inode *inode, unsigned char *buffer,
+                       size_t start_sector, unsigned int nsectors)
+{
+  struct rd_struct_s *dev;
+  if (inode)
+    {
+      dev = (struct rd_struct_s *)inode->i_private;
+      if (dev &&
+          start_sector < dev->rd_nsectors &&
+          start_sector + nsectors <= dev->rd_nsectors)
+        {
+          memcpy(buffer,
+                 &dev->rd_buffer[start_sector * dev->rd_sectsize],
+                 nsectors * dev->rd_sectsize);
+          return nsectors;
+        }
+    }
+  return -EINVAL;
+}
+
+/****************************************************************************
+ * Name: rd_write
+ *
+ * Description: Write the specified number of sectors
+ *
+ ****************************************************************************/
+
+static ssize_t rd_write(FAR struct inode *inode, const unsigned char *buffer,
+                        size_t start_sector, unsigned int nsectors)
+{
+  struct rd_struct_s *dev;
+  if (inode)
+    {
+      dev = (struct rd_struct_s *)inode->i_private;
+      if (dev &&
+          start_sector < dev->rd_nsectors &&
+          start_sector + nsectors <= dev->rd_nsectors)
+        {
+          memcpy(&dev->rd_buffer[start_sector * dev->rd_sectsize],
+                 buffer,
+                 nsectors * dev->rd_sectsize);
+          return nsectors;
+        }
+    }
+  return -EINVAL;
+}
+
+/****************************************************************************
+ * Name: rd_geometry
+ *
+ * Description: Return device geometry
+ *
+ ****************************************************************************/
+
+static int rd_geometry(FAR struct inode *inode, struct geometry *geometry)
+{
+  struct rd_struct_s *dev;
+  if (inode && geometry)
+    {
+      dev = (struct rd_struct_s *)inode->i_private;
+      geometry->geo_available     = TRUE;
+      geometry->geo_mediachanged  = FALSE;
+      geometry->geo_writeenabled  = dev->rd_writeenabled;
+      geometry->geo_nsectors      = dev->rd_nsectors;
+      geometry->geo_sectorsize    = dev->rd_sectsize;
+      return OK;
+    }
+  return -EINVAL;
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: rd_register
+ *
+ * Description: Register the a ramdisk
+
+ ****************************************************************************/
+
+int rd_register(int minor, ubyte *buffer, uint32 nsectors, uint16 sectsize,
+                boolean writeenabled)
+{
+  struct rd_struct_s *dev;
+  char devname[16];
+  int ret = -ENOMEM;
+
+  /* Sanity check */
+
+#ifdef CONFIG_DEBUG
+  if (minor < 0 || minor > 255 || !buffer || !nsectors || !sectsize)
+    {
+      return -EINVAL;
+    }
+#endif
+
+  /* Allocate a ramdisk device structure */
+
+  dev = (struct rd_struct_s *)malloc(sizeof(struct rd_struct_s));
+  if (dev)
+    {
+      /* Initialize the ramdisk device structure */
+
+      dev->rd_nsectors     = nsectors;     /* Number of sectors on device */
+      dev->rd_sectsize     = sectsize;     /* The size of one sector */
+      dev->rd_writeenabled = writeenabled; /* TRUE: can write to ram disk */
+      dev->rd_buffer       = buffer;       /* RAM disk backup memory */
+
+      /* Create a ramdisk device name */
+
+      snprintf(devname, 16, "/dev/ram%d", minor);
+
+      /* Inode private data is a reference to the ramdisk device stgructure */
+
+      ret = register_blockdriver(devname, &g_bops, 0, dev);
+      if (ret < 0)
+        {
+          free(dev);
+        }
+    }
+  return ret;
+}