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Diffstat (limited to 'apps/drivers/device/cdev.cpp')
-rw-r--r-- | apps/drivers/device/cdev.cpp | 396 |
1 files changed, 396 insertions, 0 deletions
diff --git a/apps/drivers/device/cdev.cpp b/apps/drivers/device/cdev.cpp new file mode 100644 index 000000000..6b8bf0c2d --- /dev/null +++ b/apps/drivers/device/cdev.cpp @@ -0,0 +1,396 @@ +/**************************************************************************** + * + * Copyright (C) 2012 PX4 Development Team. All rights reserved. + * + * 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 PX4 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. + * + ****************************************************************************/ + +/** + * @file Character device base class. + */ + +#include "device.h" + +#include <sys/ioctl.h> +#include <arch/irq.h> + +#include <stdlib.h> +#include <stdio.h> + +#ifdef CONFIG_DISABLE_POLL +# error This driver is not compatible with CONFIG_DISABLE_POLL +#endif + +namespace device +{ + +/* how much to grow the poll waiter set each time it has to be increased */ +static const unsigned pollset_increment = 0; + +/* + * The standard NuttX operation dispatch table can't call C++ member functions + * directly, so we have to bounce them through this dispatch table. + */ +static int cdev_open(struct file *filp); +static int cdev_close(struct file *filp); +static ssize_t cdev_read(struct file *filp, char *buffer, size_t buflen); +static ssize_t cdev_write(struct file *filp, const char *buffer, size_t buflen); +static off_t cdev_seek(struct file *filp, off_t offset, int whence); +static int cdev_ioctl(struct file *filp, int cmd, unsigned long arg); +static int cdev_poll(struct file *filp, struct pollfd *fds, bool setup); + +/** + * Character device indirection table. + * + * Every cdev we register gets the same function table; we use the private data + * field in the inode to store the instance pointer. + * + * Note that we use the GNU extension syntax here because we don't get designated + * initialisers in gcc 4.6. + */ +static const struct file_operations cdev_fops = { +open : cdev_open, +close : cdev_close, +read : cdev_read, +write : cdev_write, +seek : cdev_seek, +ioctl : cdev_ioctl, +poll : cdev_poll, +}; + +CDev::CDev(const char *name, + const char *devname, + int irq) : + // base class + Device(name, irq), + // public + // protected + // private + _devname(devname), + _registered(false), + _open_count(0) +{ + for (unsigned i = 0; i < _max_pollwaiters; i++) + _pollset[i] = nullptr; +} + +CDev::~CDev() +{ + if (_registered) + unregister_driver(_devname); +} + +int +CDev::init() +{ + int ret = OK; + + // base class init first + ret = Device::init(); + + if (ret != OK) + goto out; + + // now register the driver + ret = register_driver(_devname, &cdev_fops, 0666, (void *)this); + + if (ret != OK) + goto out; + + _registered = true; + +out: + return ret; +} + +/* + * Default implementations of the character device interface + */ +int +CDev::open(struct file *filp) +{ + int ret = OK; + + lock(); + /* increment the open count */ + _open_count++; + + if (_open_count == 1) { + + /* first-open callback may decline the open */ + ret = open_first(filp); + + if (ret != OK) + _open_count--; + } + + unlock(); + + return ret; +} + +int +CDev::open_first(struct file *filp) +{ + return OK; +} + +int +CDev::close(struct file *filp) +{ + int ret = OK; + + lock(); + + if (_open_count > 0) { + /* decrement the open count */ + _open_count--; + + /* callback cannot decline the close */ + if (_open_count == 0) + ret = close_last(filp); + + } else { + ret = -EBADF; + } + + unlock(); + + return ret; +} + +int +CDev::close_last(struct file *filp) +{ + return OK; +} + +ssize_t +CDev::read(struct file *filp, char *buffer, size_t buflen) +{ + return -ENOSYS; +} + +ssize_t +CDev::write(struct file *filp, const char *buffer, size_t buflen) +{ + return -ENOSYS; +} + +off_t +CDev::seek(struct file *filp, off_t offset, int whence) +{ + return -ENOSYS; +} + +int +CDev::ioctl(struct file *filp, int cmd, unsigned long arg) +{ + switch (cmd) { + + /* fetch a pointer to the driver's private data */ + case DIOC_GETPRIV: + *(void **)(uintptr_t)arg = (void *)this; + return OK; + } + + return -ENOTTY; +} + +int +CDev::poll(struct file *filp, struct pollfd *fds, bool setup) +{ + int ret = OK; + + /* + * Lock against pollnotify() (and possibly other callers) + */ + lock(); + + if (setup) { + /* + * Save the file pointer in the pollfd for the subclass' + * benefit. + */ + fds->priv = (void *)filp; + + /* + * Handle setup requests. + */ + ret = store_poll_waiter(fds); + + if (ret == OK) { + + /* + * Check to see whether we should send a poll notification + * immediately. + */ + fds->revents |= fds->events & poll_state(filp); + + /* yes? post the notification */ + if (fds->revents != 0) + sem_post(fds->sem); + } + + } else { + /* + * Handle a teardown request. + */ + ret = remove_poll_waiter(fds); + } + + unlock(); + + return ret; +} + +void +CDev::poll_notify(pollevent_t events) +{ + /* lock against poll() as well as other wakeups */ + irqstate_t state = irqsave(); + + for (unsigned i = 0; i < _max_pollwaiters; i++) + if (nullptr != _pollset[i]) + poll_notify_one(_pollset[i], events); + + irqrestore(state); +} + +void +CDev::poll_notify_one(struct pollfd *fds, pollevent_t events) +{ + /* update the reported event set */ + fds->revents |= fds->events & events; + + /* if the state is now interesting, wake the waiter if it's still asleep */ + /* XXX semcount check here is a vile hack; counting semphores should not be abused as cvars */ + if ((fds->revents != 0) && (fds->sem->semcount <= 0)) + sem_post(fds->sem); +} + +pollevent_t +CDev::poll_state(struct file *filp) +{ + /* by default, no poll events to report */ + return 0; +} + +int +CDev::store_poll_waiter(struct pollfd *fds) +{ + /* + * Look for a free slot. + */ + for (unsigned i = 0; i < _max_pollwaiters; i++) { + if (nullptr == _pollset[i]) { + + /* save the pollfd */ + _pollset[i] = fds; + + return OK; + } + } + + return ENOMEM; +} + +int +CDev::remove_poll_waiter(struct pollfd *fds) +{ + for (unsigned i = 0; i < _max_pollwaiters; i++) { + if (fds == _pollset[i]) { + + _pollset[i] = nullptr; + return OK; + + } + } + + puts("poll: bad fd state"); + return -EINVAL; +} + +static int +cdev_open(struct file *filp) +{ + CDev *cdev = (CDev *)(filp->f_inode->i_private); + + return cdev->open(filp); +} + +static int +cdev_close(struct file *filp) +{ + CDev *cdev = (CDev *)(filp->f_inode->i_private); + + return cdev->close(filp); +} + +static ssize_t +cdev_read(struct file *filp, char *buffer, size_t buflen) +{ + CDev *cdev = (CDev *)(filp->f_inode->i_private); + + return cdev->read(filp, buffer, buflen); +} + +static ssize_t +cdev_write(struct file *filp, const char *buffer, size_t buflen) +{ + CDev *cdev = (CDev *)(filp->f_inode->i_private); + + return cdev->write(filp, buffer, buflen); +} + +static off_t +cdev_seek(struct file *filp, off_t offset, int whence) +{ + CDev *cdev = (CDev *)(filp->f_inode->i_private); + + return cdev->seek(filp, offset, whence); +} + +static int +cdev_ioctl(struct file *filp, int cmd, unsigned long arg) +{ + CDev *cdev = (CDev *)(filp->f_inode->i_private); + + return cdev->ioctl(filp, cmd, arg); +} + +static int +cdev_poll(struct file *filp, struct pollfd *fds, bool setup) +{ + CDev *cdev = (CDev *)(filp->f_inode->i_private); + + return cdev->poll(filp, fds, setup); +} + +} // namespace device
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