aboutsummaryrefslogtreecommitdiff
path: root/nuttx/drivers/ramdisk.c
diff options
context:
space:
mode:
Diffstat (limited to 'nuttx/drivers/ramdisk.c')
-rw-r--r--nuttx/drivers/ramdisk.c342
1 files changed, 342 insertions, 0 deletions
diff --git a/nuttx/drivers/ramdisk.c b/nuttx/drivers/ramdisk.c
new file mode 100644
index 000000000..91912b25c
--- /dev/null
+++ b/nuttx/drivers/ramdisk.c
@@ -0,0 +1,342 @@
+/****************************************************************************
+ * drivers/ramdisk.c
+ *
+ * Copyright (C) 2008-2009, 2011 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 <sys/types.h>
+#include <sys/ioctl.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <debug.h>
+#include <errno.h>
+
+#include <nuttx/kmalloc.h>
+#include <nuttx/fs/fs.h>
+#include <nuttx/ramdisk.h>
+
+/****************************************************************************
+ * Private Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+struct rd_struct_s
+{
+ uint32_t rd_nsectors; /* Number of sectors on device */
+ uint16_t rd_sectsize; /* The size of one sector */
+#ifdef CONFIG_FS_WRITABLE
+ bool rd_writeenabled; /* true: can write to ram disk */
+ uint8_t *rd_buffer; /* RAM disk backup memory */
+#else
+ const uint8_t *rd_buffer; /* ROM disk backup memory */
+#endif
+};
+
+/****************************************************************************
+ * 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);
+#ifdef CONFIG_FS_WRITABLE
+static ssize_t rd_write(FAR struct inode *inode, const unsigned char *buffer,
+ size_t start_sector, unsigned int nsectors);
+#endif
+static int rd_geometry(FAR struct inode *inode, struct geometry *geometry);
+static int rd_ioctl(FAR struct inode *inode, int cmd, unsigned long arg);
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+static const struct block_operations g_bops =
+{
+ rd_open, /* open */
+ rd_close, /* close */
+ rd_read, /* read */
+#ifdef CONFIG_FS_WRITABLE
+ rd_write, /* write */
+#else
+ NULL, /* write */
+#endif
+ rd_geometry, /* geometry */
+ rd_ioctl /* ioctl */
+};
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: rd_open
+ *
+ * Description: Open the block device
+ *
+ ****************************************************************************/
+
+static int rd_open(FAR struct inode *inode)
+{
+ fvdbg("Entry\n");
+ return OK;
+}
+
+/****************************************************************************
+ * Name: rd_closel
+ *
+ * Description: close the block device
+ *
+ ****************************************************************************/
+
+static int rd_close(FAR struct inode *inode)
+{
+ fvdbg("Entry\n");
+ 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;
+
+ DEBUGASSERT(inode && inode->i_private);
+ dev = (struct rd_struct_s *)inode->i_private;
+
+ fvdbg("sector: %d nsectors: %d sectorsize: %d\n",
+ start_sector, dev->rd_sectsize, nsectors);
+
+ if (start_sector < dev->rd_nsectors &&
+ start_sector + nsectors <= dev->rd_nsectors)
+ {
+ fvdbg("Transfer %d bytes from %p\n",
+ nsectors * dev->rd_sectsize,
+ &dev->rd_buffer[start_sector * dev->rd_sectsize]);
+
+ 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
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_FS_WRITABLE
+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;
+
+ DEBUGASSERT(inode && inode->i_private);
+ dev = (struct rd_struct_s *)inode->i_private;
+
+ fvdbg("sector: %d nsectors: %d sectorsize: %d\n",
+ start_sector, dev->rd_sectsize, nsectors);
+
+ if (!dev->rd_writeenabled)
+ {
+ return -EACCES;
+ }
+ else if (start_sector < dev->rd_nsectors &&
+ start_sector + nsectors <= dev->rd_nsectors)
+ {
+ fvdbg("Transfer %d bytes from %p\n",
+ nsectors * dev->rd_sectsize,
+ &dev->rd_buffer[start_sector * dev->rd_sectsize]);
+
+ memcpy(&dev->rd_buffer[start_sector * dev->rd_sectsize],
+ buffer,
+ nsectors * dev->rd_sectsize);
+ return nsectors;
+ }
+
+ return -EFBIG;
+}
+#endif
+
+/****************************************************************************
+ * Name: rd_geometry
+ *
+ * Description: Return device geometry
+ *
+ ****************************************************************************/
+
+static int rd_geometry(FAR struct inode *inode, struct geometry *geometry)
+{
+ struct rd_struct_s *dev;
+
+ fvdbg("Entry\n");
+
+ DEBUGASSERT(inode);
+ if (geometry)
+ {
+ dev = (struct rd_struct_s *)inode->i_private;
+ geometry->geo_available = true;
+ geometry->geo_mediachanged = false;
+#ifdef CONFIG_FS_WRITABLE
+ geometry->geo_writeenabled = dev->rd_writeenabled;
+#else
+ geometry->geo_writeenabled = false;
+#endif
+ geometry->geo_nsectors = dev->rd_nsectors;
+ geometry->geo_sectorsize = dev->rd_sectsize;
+
+ fvdbg("available: true mediachanged: false writeenabled: %s\n",
+ geometry->geo_writeenabled ? "true" : "false");
+ fvdbg("nsectors: %d sectorsize: %d\n",
+ geometry->geo_nsectors, geometry->geo_sectorsize);
+
+ return OK;
+ }
+
+ return -EINVAL;
+}
+
+/****************************************************************************
+ * Name: rd_ioctl
+ *
+ * Description: Return device geometry
+ *
+ ****************************************************************************/
+
+static int rd_ioctl(FAR struct inode *inode, int cmd, unsigned long arg)
+{
+ struct rd_struct_s *dev ;
+ void **ppv = (void**)((uintptr_t)arg);
+
+ fvdbg("Entry\n");
+
+ /* Only one ioctl command is supported */
+
+ DEBUGASSERT(inode && inode->i_private);
+ if (cmd == BIOC_XIPBASE && ppv)
+ {
+ dev = (struct rd_struct_s *)inode->i_private;
+ *ppv = (void*)dev->rd_buffer;
+
+ fvdbg("ppv: %p\n", *ppv);
+ return OK;
+ }
+
+ return -ENOTTY;
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: ramdisk_register
+ *
+ * Description: Register the a ramdisk
+
+ ****************************************************************************/
+
+#ifdef CONFIG_FS_WRITABLE
+int ramdisk_register(int minor, uint8_t *buffer, uint32_t nsectors,
+ uint16_t sectsize, bool writeenabled)
+#else
+int romdisk_register(int minor, uint8_t *buffer, uint32_t nsectors,
+ uint16_t sectsize)
+#endif
+{
+ struct rd_struct_s *dev;
+ char devname[16];
+ int ret = -ENOMEM;
+
+ fvdbg("buffer: %p nsectors: %d sectsize: %d\n", buffer, nsectors, sectsize);
+
+ /* 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 *)kmalloc(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 */
+#ifdef CONFIG_FS_WRITABLE
+ dev->rd_writeenabled = writeenabled; /* true: can write to ram disk */
+#endif
+ 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)
+ {
+ fdbg("register_blockdriver failed: %d\n", -ret);
+ kfree(dev);
+ }
+ }
+ return ret;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-08-31 06:16:18 +0000