text: /****************************************************************************
   *
   *   Copyright (c) 2012-2014 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 vdevice.h
   *
   * Definitions for the generic base classes in the virtual device framework.
   */
  
  #pragma once
  
  /*
   * Includes here should only cover the needs of the framework definitions.
   */
  #include <px4_posix.h>
  
  #include <errno.h>
  #include <stdbool.h>
  #include <stdio.h>
  #include <stddef.h>
  #include <stdint.h>
  #include <semaphore.h>
  
  #define DEVICE_LOG(FMT, ...) PX4_LOG_NAMED(_name, FMT, ##__VA_ARGS__)
  #define DEVICE_DEBUG(FMT, ...) PX4_LOG_NAMED_COND(_name, _debug_enabled, FMT, ##__VA_ARGS__)
  
  /**
   * Namespace encapsulating all device framework classes, functions and data.
   */
  namespace device __EXPORT
  {
  
  struct file_t {
  	int fd;
  	int flags;
  	mode_t mode;
  	void *priv;
  	void *vdev;
  
  	file_t() : fd(-1), flags(0), priv(NULL), vdev(NULL) {}
  	file_t(int f, void *c, int d) : fd(d), flags(f), priv(NULL), vdev(c) {}
  };
  
  /**
   * Fundamental base class for all physical drivers (I2C, SPI).
   *
   * This class provides the basic driver template for I2C and SPI devices
   */
  class __EXPORT Device
  {
  public:
  	/**
  	 * Destructor.
  	 *
  	 * Public so that anonymous devices can be destroyed.
  	 */
  	virtual ~Device();
  
  	/*
  	 * Direct access methods.
  	 */
  
  	/**
  	 * Initialise the driver and make it ready for use.
  	 *
  	 * @return	OK if the driver initialized OK, negative errno otherwise;
  	 */
  	virtual int	init();
  
  	/**
  	 * Read directly from the device.
  	 *
  	 * The actual size of each unit quantity is device-specific.
  	 *
  	 * @param offset	The device address at which to start reading
  	 * @param data		The buffer into which the read values should be placed.
  	 * @param count		The number of items to read.
  	 * @return		The number of items read on success, negative errno otherwise.
  	 */
  	virtual int	dev_read(unsigned address, void *data, unsigned count);
  
  	/**
  	 * Write directly to the device.
  	 *
  	 * The actual size of each unit quantity is device-specific.
  	 *
  	 * @param address	The device address at which to start writing.
  	 * @param data		The buffer from which values should be read.
  	 * @param count		The number of items to write.
  	 * @return		The number of items written on success, negative errno otherwise.
  	 */
  	virtual int	dev_write(unsigned address, void *data, unsigned count);
  
  	/**
  	 * Perform a device-specific operation.
  	 *
  	 * @param operation     The operation to perform.
  	 * @param arg           An argument to the operation.
  	 * @return              Negative errno on error, OK or positive value on success.
  	 */
  	virtual int     dev_ioctl(unsigned operation, unsigned &arg);
  
  	/*
  	  device bus types for DEVID
  	 */
  	enum DeviceBusType {
  		DeviceBusType_UNKNOWN = 0,
  		DeviceBusType_I2C     = 1,
  		DeviceBusType_SPI     = 2,
  		DeviceBusType_UAVCAN  = 3,
  		DeviceBusType_SIM     = 4,
  	};
  
  	/*
  	  broken out device elements. The bitfields are used to keep
  	  the overall value small enough to fit in a float accurately,
  	  which makes it possible to transport over the MAVLink
  	  parameter protocol without loss of information.
  	 */
  	struct DeviceStructure {
  		enum DeviceBusType bus_type : 3;
  			uint8_t bus: 5;    // which instance of the bus type
  			uint8_t address;   // address on the bus (eg. I2C address)
  			uint8_t devtype;   // device class specific device type
  		};
  
  		union DeviceId {
  		struct DeviceStructure devid_s;
  		uint32_t devid;
  	};
  
  protected:
  	const char	*_name;			/**< driver name */
  	char		*_lock_name;		/**< name of the semaphore */
  	bool		_debug_enabled;		/**< if true, debug messages are printed */
  	union DeviceId	_device_id;             /**< device identifier information */
  
  	/**
  	 * Constructor
  	 *
  	 * @param name		Driver name
  	 */
  	Device(const char *name);
  
  	/**
  	 * Take the driver lock.
  	 *
  	 * Each driver instance has its own lock/semaphore.
  	 *
  	 * Note that we must loop as the wait may be interrupted by a signal.
  	 */
  	void		lock()
  	{
  		DEVICE_DEBUG("lock");
  		do {} while (px4_sem_wait(&_lock) != 0);
  	}
  
  	/**
  	 * Release the driver lock.
  	 */
  	void		unlock()
  	{
  		DEVICE_DEBUG("unlock");
  		px4_sem_post(&_lock);
  	}
  
  private:
  	px4_sem_t		_lock;
  
  	/** disable copy construction for this and all subclasses */
  	Device(const Device &);
  
  	/** disable assignment for this and all subclasses */
  	Device &operator = (const Device &);
  };
  
  /**
   * Abstract class for any virtual character device
   */
  class __EXPORT VDev : public Device
  {
  public:
  	/**
  	 * Constructor
  	 *
  	 * @param name		Driver name
  	 * @param devname	Device node name
  	 */
  	VDev(const char *name, const char *devname);
  
  	/**
  	 * Destructor
  	 */
  	virtual ~VDev();
  
  	virtual int	init();
  
  	/**
  	 * Perform a poll setup/teardown operation. Based on NuttX implementation.
  	 *
  	 * This is handled internally and should not normally be overridden.
  	 *
  	 * @param filep	Pointer to the internal file structure.
  	 * @param fds		Poll descriptor being waited on.
  	 * @param setup		True if this is establishing a request, false if
  	 *			it is being torn down.
  	 * @return		OK on success, or -errno otherwise.
  	 */
  	virtual int	poll(file_t *filep, px4_pollfd_struct_t *fds, bool setup);
  
  	/**
  	 * Test whether the device is currently open.
  	 *
  	 * This can be used to avoid tearing down a device that is still active.
  	 * Note - not virtual, cannot be overridden by a subclass.
  	 *
  	 * @return              True if the device is currently open.
  	 */
  	bool            is_open() { return _open_count > 0; }
  
  	/**
  	 * Handle an open of the device.
  	 *
  	 * This function is called for every open of the device. The default
  	 * implementation maintains _open_count and always returns OK.
  	 *
  	 * @param filep		Pointer to the NuttX file structure.
  	 * @return		OK if the open is allowed, -errno otherwise.
  	 */
  	virtual int	open(file_t *filep);
  
  	/**
  	 * Handle a close of the device.
  	 *
  	 * This function is called for every close of the device. The default
  	 * implementation maintains _open_count and returns OK as long as it is not zero.
  	 *
  	 * @param filep		Pointer to the NuttX file structure.
  	 * @return		OK if the close was successful, -errno otherwise.
  	 */
  	virtual int	close(file_t *filep);
  
  	/**
  	 * Perform a read from the device.
  	 *
  	 * The default implementation returns -ENOSYS.
  	 *
  	 * @param filep		Pointer to the NuttX file structure.
  	 * @param buffer	Pointer to the buffer into which data should be placed.
  	 * @param buflen	The number of bytes to be read.
  	 * @return		The number of bytes read or -errno otherwise.
  	 */
  	virtual ssize_t	read(file_t *filep, char *buffer, size_t buflen);
  
  	/**
  	 * Perform a write to the device.
  	 *
  	 * The default implementation returns -ENOSYS.
  	 *
  	 * @param filep		Pointer to the NuttX file structure.
  	 * @param buffer	Pointer to the buffer from which data should be read.
  	 * @param buflen	The number of bytes to be written.
  	 * @return		The number of bytes written or -errno otherwise.
  	 */
  	virtual ssize_t	write(file_t *filep, const char *buffer, size_t buflen);
  
  	/**
  	 * Perform a logical seek operation on the device.
  	 *
  	 * The default implementation returns -ENOSYS.
  	 *
  	 * @param filep		Pointer to the NuttX file structure.
  	 * @param offset	The new file position relative to whence.
  	 * @param whence	SEEK_OFS, SEEK_CUR or SEEK_END.
  	 * @return		The previous offset, or -errno otherwise.
  	 */
  	virtual off_t	seek(file_t *filep, off_t offset, int whence);
  
  	/**
  	 * Perform an ioctl operation on the device.
  	 *
  	 * The default implementation handles DIOC_GETPRIV, and otherwise
  	 * returns -ENOTTY. Subclasses should call the default implementation
  	 * for any command they do not handle themselves.
  	 *
  	 * @param filep		Pointer to the NuttX file structure.
  	 * @param cmd		The ioctl command value.
  	 * @param arg		The ioctl argument value.
  	 * @return		OK on success, or -errno otherwise.
  	 */
  	virtual int	ioctl(file_t *filep, int cmd, unsigned long arg);
  
  	static VDev *getDev(const char *path);
  	static void showFiles(void);
  	static void showDevices(void);
  	static void showTopics(void);
  	static const char *devList(unsigned int *next);
  	static const char *topicList(unsigned int *next);
  
  	/**
  	 * Get the device name.
  	 *
  	 * @return the file system string of the device handle
  	 */
  	const char	*get_devname() { return _devname; }
  
  protected:
  
  	int register_driver(const char *name, void *data);
  	int unregister_driver(const char *name);
  
  	/**
  	 * Check the current state of the device for poll events from the
  	 * perspective of the file.
  	 *
  	 * This function is called by the default poll() implementation when
  	 * a poll is set up to determine whether the poll should return immediately.
  	 *
  	 * The default implementation returns no events.
  	 *
  	 * @param filep		The file that's interested.
  	 * @return		The current set of poll events.
  	 */
  	virtual pollevent_t poll_state(file_t *filep);
  
  	/**
  	 * Report new poll events.
  	 *
  	 * This function should be called anytime the state of the device changes
  	 * in a fashion that might be interesting to a poll waiter.
  	 *
  	 * @param events	The new event(s) being announced.
  	 */
  	virtual void	poll_notify(pollevent_t events);
  
  	/**
  	 * Internal implementation of poll_notify.
  	 *
  	 * @param fds		A poll waiter to notify.
  	 * @param events	The event(s) to send to the waiter.
  	 */
  	virtual void	poll_notify_one(px4_pollfd_struct_t *fds, pollevent_t events);
  
  	/**
  	 * Notification of the first open.
  	 *
  	 * This function is called when the device open count transitions from zero
  	 * to one.  The driver lock is held for the duration of the call.
  	 *
  	 * The default implementation returns OK.
  	 *
  	 * @param filep		Pointer to the NuttX file structure.
  	 * @return		OK if the open should proceed, -errno otherwise.
  	 */
  	virtual int	open_first(file_t *filep);
  
  	/**
  	 * Notification of the last close.
  	 *
  	 * This function is called when the device open count transitions from
  	 * one to zero.  The driver lock is held for the duration of the call.
  	 *
  	 * The default implementation returns OK.
  	 *
  	 * @param filep		Pointer to the NuttX file structure.
  	 * @return		OK if the open should return OK, -errno otherwise.
  	 */
  	virtual int	close_last(file_t *filep);
  
  	/**
  	 * Register a class device name, automatically adding device
  	 * class instance suffix if need be.
  	 *
  	 * @param class_devname   Device class name
  	 * @return class_instamce Class instance created, or -errno on failure
  	 */
  	virtual int register_class_devname(const char *class_devname);
  
  	/**
  	 * Register a class device name, automatically adding device
  	 * class instance suffix if need be.
  	 *
  	 * @param class_devname   Device class name
  	 * @param class_instance  Device class instance from register_class_devname()
  	 * @return		  OK on success, -errno otherwise
  	 */
  	virtual int unregister_class_devname(const char *class_devname, unsigned class_instance);
  
  	bool		_pub_blocked;		/**< true if publishing should be blocked */
  
  private:
  	static const unsigned _max_pollwaiters = 8;
  
  	const char	*_devname;		/**< device node name */
  	bool		_registered;		/**< true if device name was registered */
  	unsigned	_open_count;		/**< number of successful opens */
  
  	px4_pollfd_struct_t	*_pollset[_max_pollwaiters];
  
  	/**
  	 * Store a pollwaiter in a slot where we can find it later.
  	 *
  	 * Expands the pollset as required.  Must be called with the driver locked.
  	 *
  	 * @return		OK, or -errno on error.
  	 */
  	int		store_poll_waiter(px4_pollfd_struct_t *fds);
  
  	/**
  	 * Remove a poll waiter.
  	 *
  	 * @return		OK, or -errno on error.
  	 */
  	int		remove_poll_waiter(px4_pollfd_struct_t *fds);
  
  	/* do not allow copying this class */
  	VDev(const VDev &);
  	//VDev operator=(const VDev&);
  };
  
  #if 0
  /**
   * Abstract class for character device accessed via PIO
   */
  class __EXPORT VPIO : public CDev
  {
  public:
  	/**
  	 * Constructor
  	 *
  	 * @param name		Driver name
  	 * @param devname	Device node name
  	 * @param base		Base address of the device PIO area
  	 * @param irq		Interrupt assigned to the device (or zero if none)
  	 */
  	PIO(const char *name,
  	    const char *devname,
  	    unsigned long base
  	   );
  	virtual ~PIO();
  
  	virtual int	init();
  
  protected:
  
  	/**
  	 * Read a register
  	 *
  	 * @param offset	Register offset in bytes from the base address.
  	 */
  	uint32_t	reg(uint32_t offset)
  	{
  		return *(volatile uint32_t *)(_base + offset);
  	}
  
  	/**
  	 * Write a register
  	 *
  	 * @param offset	Register offset in bytes from the base address.
  	 * @param value	Value to write.
  	 */
  	void		reg(uint32_t offset, uint32_t value)
  	{
  		*(volatile uint32_t *)(_base + offset) = value;
  	}
  
  	/**
  	 * Modify a register
  	 *
  	 * Note that there is a risk of a race during the read/modify/write cycle
  	 * that must be taken care of by the caller.
  	 *
  	 * @param offset	Register offset in bytes from the base address.
  	 * @param clearbits	Bits to clear in the register
  	 * @param setbits	Bits to set in the register
  	 */
  	void		modify(uint32_t offset, uint32_t clearbits, uint32_t setbits)
  	{
  		uint32_t val = reg(offset);
  		val &= ~clearbits;
  		val |= setbits;
  		reg(offset, val);
  	}
  
  private:
  	unsigned long	_base;
  };
  #endif
  
  } // namespace device
  
  // class instance for primary driver of each class
  enum CLASS_DEVICE {
  	CLASS_DEVICE_PRIMARY = 0,
  	CLASS_DEVICE_SECONDARY = 1,
  	CLASS_DEVICE_TERTIARY = 2
  };
  
  