Fresh import of the PX4 firmware sources.

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