/****************************************************************************
*
* 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
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* 2. Redistributions in binary form must reproduce the above copyright
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* the documentation and/or other materials provided with the
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* 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
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****************************************************************************/
/**
* @file device.h
*
* Definitions for the generic base classes in the device framework.
*/
#ifndef _DEVICE_DEVICE_H
#define _DEVICE_DEVICE_H
/*
* Includes here should only cover the needs of the framework definitions.
*/
#include <nuttx/config.h>
#include <errno.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <poll.h>
#include <nuttx/fs/fs.h>
/**
* Namespace encapsulating all device framework classes, functions and data.
*/
namespace device __EXPORT
{
/**
* Fundamental base class for all device drivers.
*
* This class handles the basic "being a driver" things, including
* interrupt registration and dispatch.
*/
class __EXPORT Device
{
public:
/**
* Destructor.
*
* Public so that anonymous devices can be destroyed.
*/
virtual ~Device();
/**
* Interrupt handler.
*/
virtual void interrupt(void *ctx); /**< interrupt handler */
/*
* 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 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 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 ioctl(unsigned operation, unsigned &arg);
/*
device bus types for DEVID
*/
enum DeviceBusType {
DeviceBusType_UNKNOWN = 0,
DeviceBusType_I2C = 1,
DeviceBusType_SPI = 2
};
/*
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 */
bool _debug_enabled; /**< if true, debug messages are printed */
union DeviceId _device_id; /**< device identifier information */
/**
* Constructor
*
* @param name Driver name
* @param irq Interrupt assigned to the device.
*/
Device(const char *name,
int irq = 0);
/**
* Enable the device interrupt
*/
void interrupt_enable();
/**
* Disable the device interrupt
*/
void interrupt_disable();
/**
* 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() {
do {} while (sem_wait(&_lock) != 0);
}
/**
* Release the driver lock.
*/
void unlock() {
sem_post(&_lock);
}
/**
* Log a message.
*
* The message is prefixed with the driver name, and followed
* by a newline.
*/
void log(const char *fmt, ...);
/**
* Print a debug message.
*
* The message is prefixed with the driver name, and followed
* by a newline.
*/
void debug(const char *fmt, ...);
private:
int _irq;
bool _irq_attached;
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 &);
/**
* Register ourselves as a handler for an interrupt
*
* @param irq The interrupt to claim
* @return OK if the interrupt was registered
*/
int dev_register_interrupt(int irq);
/**
* Unregister ourselves as a handler for any interrupt
*/
void dev_unregister_interrupt();
/**
* Interrupt dispatcher
*
* @param irq The interrupt that has been triggered.
* @param context Pointer to the interrupted context.
*/
static void dev_interrupt(int irq, void *context);
};
/**
* Abstract class for any character device
*/
class __EXPORT CDev : public Device
{
public:
/**
* Constructor
*
* @param name Driver name
* @param devname Device node name
* @param irq Interrupt assigned to the device
*/
CDev(const char *name, const char *devname, int irq = 0);
/**
* Destructor
*/
virtual ~CDev();
virtual int init();
/**
* 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 filp Pointer to the NuttX file structure.
* @return OK if the open is allowed, -errno otherwise.
*/
virtual int open(struct file *filp);
/**
* 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 filp Pointer to the NuttX file structure.
* @return OK if the close was successful, -errno otherwise.
*/
virtual int close(struct file *filp);
/**
* Perform a read from the device.
*
* The default implementation returns -ENOSYS.
*
* @param filp 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(struct file *filp, char *buffer, size_t buflen);
/**
* Perform a write to the device.
*
* The default implementation returns -ENOSYS.
*
* @param filp 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(struct file *filp, const char *buffer, size_t buflen);
/**
* Perform a logical seek operation on the device.
*
* The default implementation returns -ENOSYS.
*
* @param filp 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(struct file *filp, 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 filp 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(struct file *filp, int cmd, unsigned long arg);
/**
* Perform a poll setup/teardown operation.
*
* This is handled internally and should not normally be overridden.
*
* @param filp Pointer to the NuttX file structure.
* @param fds Poll descriptor being waited on.
* @param arg True if this is establishing a request, false if
* it is being torn down.
* @return OK on success, or -errno otherwise.
*/
virtual int poll(struct file *filp, struct pollfd *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; }
protected:
/**
* Pointer to the default cdev file operations table; useful for
* registering clone devices etc.
*/
static const struct file_operations fops;
/**
* 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 filp The file that's interested.
* @return The current set of poll events.
*/
virtual pollevent_t poll_state(struct file *filp);
/**
* 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(struct pollfd *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 filp Pointer to the NuttX file structure.
* @return OK if the open should proceed, -errno otherwise.
*/
virtual int open_first(struct file *filp);
/**
* 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 filp Pointer to the NuttX file structure.
* @return OK if the open should return OK, -errno otherwise.
*/
virtual int close_last(struct file *filp);
/**
* 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 */
struct pollfd *_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(struct pollfd *fds);
/**
* Remove a poll waiter.
*
* @return OK, or -errno on error.
*/
int remove_poll_waiter(struct pollfd *fds);
};
/**
* Abstract class for character device accessed via PIO
*/
class __EXPORT PIO : 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,
uint32_t base,
int irq = 0);
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:
uint32_t _base;
};
} // namespace device
// class instance for primary driver of each class
#define CLASS_DEVICE_PRIMARY 0
#endif /* _DEVICE_DEVICE_H */
