forked from Archive/PX4-Autopilot
439 lines
12 KiB
C++
439 lines
12 KiB
C++
/****************************************************************************
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*
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* Copyright (C) 2012 PX4 Development Team. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name PX4 nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/**
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* @file Definitions for the generic base classes in the device framework.
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*/
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#ifndef _DEVICE_DEVICE_H
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#define _DEVICE_DEVICE_H
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/*
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* Includes here should only cover the needs of the framework definitions.
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*/
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#include <nuttx/config.h>
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#include <errno.h>
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#include <stdbool.h>
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#include <stddef.h>
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#include <stdint.h>
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#include <poll.h>
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#include <nuttx/fs/fs.h>
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/**
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* Namespace encapsulating all device framework classes, functions and data.
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*/
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namespace device __EXPORT
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{
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/**
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* Fundamental base class for all device drivers.
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*
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* This class handles the basic "being a driver" things, including
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* interrupt registration and dispatch.
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*/
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class __EXPORT Device
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{
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public:
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/**
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* Interrupt handler.
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*/
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virtual void interrupt(void *ctx); /**< interrupt handler */
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protected:
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const char *_name; /**< driver name */
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bool _debug_enabled; /**< if true, debug messages are printed */
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/**
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* Constructor
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*
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* @param name Driver name
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* @param irq Interrupt assigned to the device.
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*/
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Device(const char *name,
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int irq = 0);
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~Device();
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/**
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* Initialise the driver and make it ready for use.
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*
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* @return OK if the driver initialised OK.
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*/
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virtual int init();
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/**
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* Enable the device interrupt
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*/
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void interrupt_enable();
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/**
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* Disable the device interrupt
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*/
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void interrupt_disable();
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/**
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* Take the driver lock.
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*
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* Each driver instance has its own lock/semaphore.
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*
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* Note that we must loop as the wait may be interrupted by a signal.
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*/
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void lock() {
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do {} while (sem_wait(&_lock) != 0);
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}
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/**
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* Release the driver lock.
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*/
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void unlock() {
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sem_post(&_lock);
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}
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/**
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* Log a message.
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*
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* The message is prefixed with the driver name, and followed
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* by a newline.
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*/
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void log(const char *fmt, ...);
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/**
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* Print a debug message.
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*
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* The message is prefixed with the driver name, and followed
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* by a newline.
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*/
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void debug(const char *fmt, ...);
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private:
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int _irq;
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bool _irq_attached;
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sem_t _lock;
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/** disable copy construction for this and all subclasses */
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Device(const Device &);
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/** disable assignment for this and all subclasses */
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Device &operator = (const Device &);
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/**
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* Register ourselves as a handler for an interrupt
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*
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* @param irq The interrupt to claim
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* @return OK if the interrupt was registered
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*/
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int dev_register_interrupt(int irq);
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/**
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* Unregister ourselves as a handler for any interrupt
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*/
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void dev_unregister_interrupt();
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/**
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* Interrupt dispatcher
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*
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* @param irq The interrupt that has been triggered.
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* @param context Pointer to the interrupted context.
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*/
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static void dev_interrupt(int irq, void *context);
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};
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/**
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* Abstract class for any character device
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*/
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class __EXPORT CDev : public Device
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{
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public:
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/**
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* Constructor
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*
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* @param name Driver name
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* @param devname Device node name
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* @param irq Interrupt assigned to the device
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*/
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CDev(const char *name, const char *devname, int irq = 0);
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/**
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* Destructor
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*/
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~CDev();
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virtual int init();
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/**
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* Handle an open of the device.
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*
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* This function is called for every open of the device. The default
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* implementation maintains _open_count and always returns OK.
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*
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* @param filp Pointer to the NuttX file structure.
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* @return OK if the open is allowed, -errno otherwise.
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*/
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virtual int open(struct file *filp);
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/**
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* Handle a close of the device.
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*
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* This function is called for every close of the device. The default
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* implementation maintains _open_count and returns OK as long as it is not zero.
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*
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* @param filp Pointer to the NuttX file structure.
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* @return OK if the close was successful, -errno otherwise.
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*/
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virtual int close(struct file *filp);
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/**
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* Perform a read from the device.
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*
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* The default implementation returns -ENOSYS.
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*
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* @param filp Pointer to the NuttX file structure.
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* @param buffer Pointer to the buffer into which data should be placed.
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* @param buflen The number of bytes to be read.
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* @return The number of bytes read or -errno otherwise.
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*/
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virtual ssize_t read(struct file *filp, char *buffer, size_t buflen);
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/**
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* Perform a write to the device.
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*
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* The default implementation returns -ENOSYS.
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*
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* @param filp Pointer to the NuttX file structure.
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* @param buffer Pointer to the buffer from which data should be read.
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* @param buflen The number of bytes to be written.
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* @return The number of bytes written or -errno otherwise.
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*/
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virtual ssize_t write(struct file *filp, const char *buffer, size_t buflen);
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/**
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* Perform a logical seek operation on the device.
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*
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* The default implementation returns -ENOSYS.
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*
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* @param filp Pointer to the NuttX file structure.
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* @param offset The new file position relative to whence.
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* @param whence SEEK_OFS, SEEK_CUR or SEEK_END.
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* @return The previous offset, or -errno otherwise.
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*/
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virtual off_t seek(struct file *filp, off_t offset, int whence);
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/**
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* Perform an ioctl operation on the device.
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*
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* The default implementation handles DIOC_GETPRIV, and otherwise
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* returns -ENOTTY. Subclasses should call the default implementation
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* for any command they do not handle themselves.
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*
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* @param filp Pointer to the NuttX file structure.
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* @param cmd The ioctl command value.
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* @param arg The ioctl argument value.
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* @return OK on success, or -errno otherwise.
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*/
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virtual int ioctl(struct file *filp, int cmd, unsigned long arg);
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/**
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* Perform a poll setup/teardown operation.
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*
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* This is handled internally and should not normally be overridden.
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*
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* @param filp Pointer to the NuttX file structure.
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* @param fds Poll descriptor being waited on.
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* @param arg True if this is establishing a request, false if
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* it is being torn down.
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* @return OK on success, or -errno otherwise.
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*/
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virtual int poll(struct file *filp, struct pollfd *fds, bool setup);
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/**
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* Test whether the device is currently open.
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*
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* This can be used to avoid tearing down a device that is still active.
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*
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* @return True if the device is currently open.
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*/
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bool is_open() { return _open_count > 0; }
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protected:
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/**
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* Check the current state of the device for poll events from the
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* perspective of the file.
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*
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* This function is called by the default poll() implementation when
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* a poll is set up to determine whether the poll should return immediately.
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*
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* The default implementation returns no events.
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*
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* @param filp The file that's interested.
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* @return The current set of poll events.
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*/
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virtual pollevent_t poll_state(struct file *filp);
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/**
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* Report new poll events.
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*
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* This function should be called anytime the state of the device changes
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* in a fashion that might be interesting to a poll waiter.
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*
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* @param events The new event(s) being announced.
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*/
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virtual void poll_notify(pollevent_t events);
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/**
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* Internal implementation of poll_notify.
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*
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* @param fds A poll waiter to notify.
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* @param events The event(s) to send to the waiter.
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*/
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virtual void poll_notify_one(struct pollfd *fds, pollevent_t events);
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/**
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* Notification of the first open.
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*
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* This function is called when the device open count transitions from zero
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* to one. The driver lock is held for the duration of the call.
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*
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* The default implementation returns OK.
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*
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* @param filp Pointer to the NuttX file structure.
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* @return OK if the open should proceed, -errno otherwise.
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*/
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virtual int open_first(struct file *filp);
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/**
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* Notification of the last close.
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*
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* This function is called when the device open count transitions from
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* one to zero. The driver lock is held for the duration of the call.
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*
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* The default implementation returns OK.
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*
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* @param filp Pointer to the NuttX file structure.
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* @return OK if the open should return OK, -errno otherwise.
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*/
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virtual int close_last(struct file *filp);
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private:
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static const unsigned _max_pollwaiters = 8;
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const char *_devname; /**< device node name */
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bool _registered; /**< true if device name was registered */
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unsigned _open_count; /**< number of successful opens */
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struct pollfd *_pollset[_max_pollwaiters];
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/**
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* Store a pollwaiter in a slot where we can find it later.
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*
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* Expands the pollset as required. Must be called with the driver locked.
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*
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* @return OK, or -errno on error.
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*/
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int store_poll_waiter(struct pollfd *fds);
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/**
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* Remove a poll waiter.
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*
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* @return OK, or -errno on error.
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*/
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int remove_poll_waiter(struct pollfd *fds);
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};
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/**
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* Abstract class for character device accessed via PIO
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*/
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class __EXPORT PIO : public CDev
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{
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public:
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/**
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* Constructor
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*
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* @param name Driver name
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* @param devname Device node name
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* @param base Base address of the device PIO area
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* @param irq Interrupt assigned to the device (or zero if none)
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*/
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PIO(const char *name,
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const char *devname,
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uint32_t base,
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int irq = 0);
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~PIO();
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int init();
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protected:
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/**
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* Read a register
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*
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* @param offset Register offset in bytes from the base address.
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*/
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uint32_t reg(uint32_t offset) {
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return *(volatile uint32_t *)(_base + offset);
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}
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/**
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* Write a register
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*
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* @param offset Register offset in bytes from the base address.
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* @param value Value to write.
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*/
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void reg(uint32_t offset, uint32_t value) {
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*(volatile uint32_t *)(_base + offset) = value;
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}
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/**
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* Modify a register
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*
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* Note that there is a risk of a race during the read/modify/write cycle
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* that must be taken care of by the caller.
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*
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* @param offset Register offset in bytes from the base address.
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* @param clearbits Bits to clear in the register
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* @param setbits Bits to set in the register
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*/
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void modify(uint32_t offset, uint32_t clearbits, uint32_t setbits) {
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uint32_t val = reg(offset);
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val &= ~clearbits;
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val |= setbits;
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reg(offset, val);
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}
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private:
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uint32_t _base;
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};
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} // namespace device
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#endif /* _DEVICE_DEVICE_H */ |