diff options
Diffstat (limited to 'nuttx/drivers/bch/bchdev_unregister.c')
-rw-r--r-- | nuttx/drivers/bch/bchdev_unregister.c | 160 |
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; +} |