1 files changed, 160 insertions, 0 deletions
diff --git a/nuttx/drivers/bch/bchdev_unregister.c b/nuttx/drivers/bch/bchdev_unregister.c
new file mode 100644
index 000000000..8c7360882
--- /dev/null
+++ b/nuttx/drivers/bch/bchdev_unregister.c
@@ -0,0 +1,160 @@
+/****************************************************************************
+ * drivers/bch/bchdev_unregister.c
+ *
+ *   Copyright (C) 2008-2009, 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 <sys/stat.h>
+#include <sys/ioctl.h>
+
+#include <unistd.h>
+#include <fcntl.h>
+#include <sched.h>
+#include <errno.h>
+#include <assert.h>
+#include <debug.h>
+
+#include <nuttx/fs/fs.h>
+#include <nuttx/fs/ioctl.h>
+
+#include "bch_internal.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: bchdev_unregister
+ *
+ * Description:
+ *   Unregister character driver access to a block device that was created
+ *   by a previous call to bchdev_register().
+ *
+ ****************************************************************************/
+
+int bchdev_unregister(FAR const char *chardev)
+{
+  FAR struct bchlib_s *bch;
+  int fd;
+  int ret;
+
+  /* Sanity check */
+
+#ifdef CONFIG_DEBUG
+  if (!chardev)
+    {
+      return -EINVAL;
+    }
+#endif
+
+  /* Open the character driver associated with chardev */
+
+  fd = open(chardev, O_RDONLY);
+  if (fd < 0)
+    {
+      dbg("Failed to open %s: %d\n", chardev, errno);
+      return -errno;
+    }
+
+  /* Get a reference to the internal data structure.  On success, we
+   * will hold a reference count on the state structure.
+   */
+
+  ret = ioctl(fd, DIOC_GETPRIV, (unsigned long)((uintptr_t)&bch));
+  (void)close(fd);
+
+  if (ret < 0)
+    {
+      dbg("ioctl failed: %d\n", errno);
+      return -errno;
+    }
+
+  /* Lock out context switches.  If there are no other references
+   * and no context switches, then we can assume that we can safely
+   * teardown the driver.
+   */
+
+  sched_lock();
+
+  /* Check if the internal structure is non-busy (we hold one reference). */
+
+  if (bch->refs > 1)
+    {
+      ret = -EBUSY;
+      goto errout_with_lock;
+    }
+
+  /* Unregister the driver (this cannot suspend or we lose our non-preemptive
+   * state!).  Once the driver is successfully unregistered, we can assume
+   * we have exclusive access to the state instance.
+   */
+
+  ret = unregister_driver(chardev);
+  if (ret < 0)
+    {
+      goto errout_with_lock;
+    }
+
+  sched_unlock();
+
+  /* Release the internal structure */
+
+  bch->refs = 0;
+  return bchlib_teardown(bch);
+
+errout_with_lock:
+  bch->refs--;
+  sched_unlock();
+  return ret;
+}