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Diffstat (limited to 'src/drivers/device/device.h')
| -rw-r--r-- | src/drivers/device/device.h | 447 |
1 files changed, 447 insertions, 0 deletions
diff --git a/src/drivers/device/device.h b/src/drivers/device/device.h new file mode 100644 index 000000000..7d375aab9 --- /dev/null +++ b/src/drivers/device/device.h @@ -0,0 +1,447 @@ +/**************************************************************************** + * + * 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 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: + /** + * Interrupt handler. + */ + virtual void interrupt(void *ctx); /**< interrupt handler */ + +protected: + const char *_name; /**< driver name */ + bool _debug_enabled; /**< if true, debug messages are printed */ + + /** + * Constructor + * + * @param name Driver name + * @param irq Interrupt assigned to the device. + */ + Device(const char *name, + int irq = 0); + ~Device(); + + /** + * Initialise the driver and make it ready for use. + * + * @return OK if the driver initialised OK. + */ + virtual int init(); + + /** + * 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 + */ + ~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. + * + * @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); + +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); + ~PIO(); + + 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 + +#endif /* _DEVICE_DEVICE_H */
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