RTAI/addons/rtdm/core.c

/**
 * @file
 * Real-Time Driver Model for RTAI, device operation multiplexing
 *
 * @note Copyright (C) 2005 Jan Kiszka <jan.kiszka@web.de>
 * @note Copyright (C) 2005 Joerg Langenberg <joerg.langenberg@gmx.net>
 *
 * with adaptions for RTAI by Paolo Mantegazza <mantegazza@aero.polimi.it>
 *
 * RTAI is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * RTAI is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with RTAI; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

/*!
 * @ingroup driverapi
 * @defgroup interdrv Inter-Driver API
 * @{
 */

#include <linux/delay.h>






#include "rtdm/internal.h"

#define CLOSURE_RETRY_PERIOD_MS	100

#define FD_BITMAP_SIZE  ((RTDM_FD_MAX + BITS_PER_LONG-1) / BITS_PER_LONG)

struct rtdm_fildes fildes_table[RTDM_FD_MAX] =
	{ [0 ... RTDM_FD_MAX-1] = { NULL } };
static unsigned long used_fildes[FD_BITMAP_SIZE];
int open_fildes;	/* number of used descriptors */

static DECLARE_WORK_FUNC(close_callback);
static DECLARE_DELAYED_WORK_NODATA(close_work, close_callback);
static LIST_HEAD(cleanup_queue);

DEFINE_XNLOCK(rt_fildes_lock);

/**
 * @brief Retrieve and lock a device context
 *
 * @param[in] fd File descriptor
 *
 * @return Pointer to associated device context, or NULL on error
 *
 * @note The device context has to be unlocked using rtdm_context_put() when
 * it is no longer referenced.
 *
 * Environments:
 *
 * This service can be called from:
 *
 * - Kernel module initialization/cleanup code
 * - Interrupt service routine
 * - Kernel-based task
 * - User-space task (RT, non-RT)
 *
 * Rescheduling: never.
 */
struct rtdm_dev_context *rtdm_context_get(int fd)
{
	struct rtdm_dev_context *context;
	spl_t s;

	if ((unsigned int)fd >= RTDM_FD_MAX)
		return NULL;

	xnlock_get_irqsave(&rt_fildes_lock, s);

	context = fildes_table[fd].context;
	if (unlikely(!context)) {
		xnlock_put_irqrestore(&rt_fildes_lock, s);
		return NULL;
	}

	atomic_inc(&context->close_lock_count);

	xnlock_put_irqrestore(&rt_fildes_lock, s);

	return context;
}

EXPORT_SYMBOL(rtdm_context_get);

static int create_instance(struct rtdm_device *device,
			   struct rtdm_dev_context **context_ptr,
			   struct rtdm_fildes **fildes_ptr,
			   rtdm_user_info_t *user_info, int nrt_mem)
{
	struct rtdm_dev_context *context;

	int fd;
	spl_t s;

	/* 
	 * Reset to NULL so that we can always use cleanup_files/instance to
	 * revert also partially successful allocations.
	 */
	*context_ptr = NULL;
	*fildes_ptr = NULL;

	/* Reserve a file descriptor */
	xnlock_get_irqsave(&rt_fildes_lock, s);

	if (unlikely(open_fildes >= RTDM_FD_MAX)) {
		xnlock_put_irqrestore(&rt_fildes_lock, s);
		return -ENFILE;
	}

	fd = find_first_zero_bit(used_fildes, RTDM_FD_MAX);
	__set_bit(fd, used_fildes);
	open_fildes++;

	xnlock_put_irqrestore(&rt_fildes_lock, s);

	*fildes_ptr = &fildes_table[fd];

	context = device->reserved.exclusive_context;
	if (context) {
		xnlock_get_irqsave(&rt_dev_lock, s);

		if (unlikely(context->device != NULL)) {
			xnlock_put_irqrestore(&rt_dev_lock, s);
			return -EBUSY;
		}
		context->device = device;

		xnlock_put_irqrestore(&rt_dev_lock, s);
	} else {
		if (nrt_mem)
			context = kmalloc(sizeof(struct rtdm_dev_context) +
					  device->context_size, GFP_KERNEL);
		else
			context = xnmalloc(sizeof(struct rtdm_dev_context) +
					   device->context_size);
		if (unlikely(!context))
			return -ENOMEM;

		context->device = device;
	}

	*context_ptr = context;

	context->fd = fd;
	context->ops = &device->ops;
	atomic_set(&context->close_lock_count, 0);





	context->reserved.owner = NULL;



	return 0;
}

static void __cleanup_fildes(struct rtdm_fildes *fildes)
{
	__clear_bit((fildes - fildes_table), used_fildes);
	fildes->context = NULL;
	open_fildes--;
}

static void cleanup_fildes(struct rtdm_fildes *fildes)
{
	spl_t s;

	if (!fildes)
		return;

	xnlock_get_irqsave(&rt_fildes_lock, s);
	__cleanup_fildes(fildes);
	xnlock_put_irqrestore(&rt_fildes_lock, s);
}

static void cleanup_instance(struct rtdm_device *device,
			     struct rtdm_dev_context *context,
			     int nrt_mem)
{
	if (context) {
		if (device->reserved.exclusive_context)
			context->device = NULL;
		else {
			if (nrt_mem)
				kfree(context);
			else
				xnfree(context);
		}
	}

	rtdm_dereference_device(device);
}

static DECLARE_WORK_FUNC(close_callback)
{
	struct rtdm_dev_context *context;
	LIST_HEAD(deferred_list);
	int reschedule = 0;
	int err;
	spl_t s;

	xnlock_get_irqsave(&rt_fildes_lock, s);

	while (!list_empty(&cleanup_queue)) {
		context = list_first_entry(&cleanup_queue,
					   struct rtdm_dev_context,
					   reserved.cleanup);
		list_del(&context->reserved.cleanup);
		atomic_inc(&context->close_lock_count);

		xnlock_put_irqrestore(&rt_fildes_lock, s);

		err = context->ops->close_nrt(context, NULL);

		if (err == -EAGAIN ||
		    atomic_read(&context->close_lock_count) > 1) {
			atomic_dec(&context->close_lock_count);
			list_add_tail(&context->reserved.cleanup,
				      &deferred_list);
			if (err == -EAGAIN)
				reschedule = 1;
		} else {
			trace_mark(xn_rtdm, fd_closed, "fd %d", context->fd);

			cleanup_instance(context->device, context,
					 test_bit(RTDM_CREATED_IN_NRT,
						  &context->context_flags));
		}

		xnlock_get_irqsave(&rt_fildes_lock, s);
	}

	list_splice(&deferred_list, &cleanup_queue);

	xnlock_put_irqrestore(&rt_fildes_lock, s);

	if (reschedule)
		schedule_delayed_work(&close_work,
				      (HZ * CLOSURE_RETRY_PERIOD_MS) / 1000);
}

void rtdm_apc_handler(void *cookie)
{
	schedule_delayed_work(&close_work, 0);
}


int __rt_dev_open(rtdm_user_info_t *user_info, const char *path, int oflag)
{
	struct rtdm_device *device;
	struct rtdm_fildes *fildes;
	struct rtdm_dev_context *context;
	int ret;
	int nrt_mode = !rtdm_in_rt_context();

	device = get_named_device(path);
	trace_mark(xn_rtdm, open, "user_info %p path %s oflag %d device %p",
		   user_info, path, oflag, device);
	ret = -ENODEV;
	if (!device)
		goto err_out;

	ret = create_instance(device, &context, &fildes, user_info, nrt_mode);
	if (ret != 0)
		goto cleanup_out;

	if (nrt_mode) {
		context->context_flags = (1 << RTDM_CREATED_IN_NRT);
		ret = device->open_nrt(context, user_info, oflag);
	} else {
		context->context_flags = 0;
		ret = device->open_rt(context, user_info, oflag);
	}

	RTAI_ASSERT(RTDM, !rthal_local_irq_disabled(),
		    rthal_local_irq_enable(););

	if (unlikely(ret < 0))
		goto cleanup_out;

	fildes->context = context;

	trace_mark(xn_rtdm, fd_created,
		   "device %p fd %d", device, context->fd);

	return context->fd;

cleanup_out:
	cleanup_fildes(fildes);
	cleanup_instance(device, context, nrt_mode);

err_out:
	return ret;
}

EXPORT_SYMBOL(__rt_dev_open);

int __rt_dev_socket(rtdm_user_info_t *user_info, int protocol_family,
		    int socket_type, int protocol)
{
	struct rtdm_device *device;
	struct rtdm_fildes *fildes;
	struct rtdm_dev_context *context;
	int ret;
	int nrt_mode = !rtdm_in_rt_context();

	device = get_protocol_device(protocol_family, socket_type);
	trace_mark(xn_rtdm, socket, "user_info %p protocol_family %d "
		   "socket_type %d protocol %d device %p",
		   user_info, protocol_family, socket_type, protocol, device);
	ret = -EAFNOSUPPORT;
	if (!device)
		goto err_out;

	ret = create_instance(device, &context, &fildes, user_info, nrt_mode);
	if (ret != 0)
		goto cleanup_out;

	if (nrt_mode) {
		context->context_flags = (1 << RTDM_CREATED_IN_NRT);
		ret = device->socket_nrt(context, user_info, protocol);
	} else {
		context->context_flags = 0;
		ret = device->socket_rt(context, user_info, protocol);
	}

	RTAI_ASSERT(RTDM, !rthal_local_irq_disabled(),
		    rthal_local_irq_enable(););

	if (unlikely(ret < 0))
		goto cleanup_out;

	fildes->context = context;

	trace_mark(xn_rtdm, fd_created,
		   "device %p fd %d", device, context->fd);

	return context->fd;

cleanup_out:
	cleanup_fildes(fildes);
	cleanup_instance(device, context, nrt_mode);

err_out:
	return ret;
}

EXPORT_SYMBOL(__rt_dev_socket);

int __rt_dev_close(rtdm_user_info_t *user_info, int fd)
{
	struct rtdm_dev_context *context;
	spl_t s;
	int ret;
	int nrt_mode = !rtdm_in_rt_context();

	trace_mark(xn_rtdm, close, "user_info %p fd %d", user_info, fd);

	ret = -EBADF;
	if (unlikely((unsigned int)fd >= RTDM_FD_MAX))
		goto err_out;

	xnlock_get_irqsave(&rt_fildes_lock, s);

	context = fildes_table[fd].context;

	if (unlikely(!context)) {
		xnlock_put_irqrestore(&rt_fildes_lock, s);
		goto err_out;	/* -EBADF */
	}

	/* Avoid asymmetric close context by switching to nrt. */
	if (unlikely(test_bit(RTDM_CREATED_IN_NRT, &context->context_flags)) &&
	    !nrt_mode) {
		xnlock_put_irqrestore(&rt_fildes_lock, s);

		ret = -ENOSYS;
		goto err_out;
	}

	set_bit(RTDM_CLOSING, &context->context_flags);
	atomic_inc(&context->close_lock_count);

	__cleanup_fildes(&fildes_table[fd]);

	xnlock_put_irqrestore(&rt_fildes_lock, s);

	if (nrt_mode)
		ret = context->ops->close_nrt(context, user_info);
	else
		ret = context->ops->close_rt(context, user_info);

	RTAI_ASSERT(RTDM, !rthal_local_irq_disabled(),
		    rthal_local_irq_enable(););

	xnlock_get_irqsave(&rt_fildes_lock, s);

	if (ret == -EAGAIN || atomic_read(&context->close_lock_count) > 2) {
		atomic_dec(&context->close_lock_count);
		list_add(&context->reserved.cleanup, &cleanup_queue);

		xnlock_put_irqrestore(&rt_fildes_lock, s);

		if (ret == -EAGAIN) {
			rthal_apc_schedule(rtdm_apc);
			ret = 0;
		}
		goto unlock_out;
	}

	xnlock_put_irqrestore(&rt_fildes_lock, s);

	trace_mark(xn_rtdm, fd_closed, "fd %d", context->fd);

	cleanup_instance(context->device, context,
			 test_bit(RTDM_CREATED_IN_NRT,
				  &context->context_flags));

	return ret;

unlock_out:
	rtdm_context_unlock(context);

err_out:
	return ret;
}

EXPORT_SYMBOL(__rt_dev_close);

void cleanup_owned_contexts(void *owner)
{
	struct rtdm_dev_context *context;
	unsigned int fd;
	int ret;
	spl_t s;

	for (fd = 0; fd < RTDM_FD_MAX; fd++) {
		xnlock_get_irqsave(&rt_fildes_lock, s);

		context = fildes_table[fd].context;
		if (context && context->reserved.owner != owner)
			context = NULL;

		xnlock_put_irqrestore(&rt_fildes_lock, s);

		if (context) {
			if (RTAI_DEBUG(RTDM))
				xnprintf("RTDM: closing file descriptor %d.\n",
					 fd);

			ret = __rt_dev_close(NULL, fd);
			RTAI_ASSERT(RTDM, ret == 0 || ret == -EBADF,
				    /* only warn here */;);
		}
	}
}

#define MAJOR_FUNCTION_WRAPPER_TH(operation, args...)			\
do {									\
	struct rtdm_dev_context *context;				\
	struct rtdm_operations *ops;					\
	int ret;							\
									\
	context = rtdm_context_get(fd);					\
	ret = -EBADF;							\
	if (unlikely(!context))						\
		goto err_out;						\
									\
	ops = context->ops;						\
									\
	if (rtdm_in_rt_context())					\
		ret = ops->operation##_rt(context, user_info, args);	\
	else								\
		ret = ops->operation##_nrt(context, user_info, args);	\
									\
	RTAI_ASSERT(RTDM, !rthal_local_irq_disabled(), 			\
		    rthal_local_irq_enable();)

#define MAJOR_FUNCTION_WRAPPER_BH()					\
	rtdm_context_unlock(context);					\
									\
err_out:								\
	trace_mark(xn_rtdm, operation##_done, "result %d", ret);	\
	return ret;							\
} while (0)

#define MAJOR_FUNCTION_WRAPPER(operation, args...)			\
do {									\
	MAJOR_FUNCTION_WRAPPER_TH(operation, args);			\
	MAJOR_FUNCTION_WRAPPER_BH();					\
} while (0)

int __rt_dev_ioctl(rtdm_user_info_t *user_info, int fd, int request, ...)
{
	va_list args;
	void __user *arg;

	va_start(args, request);
	arg = va_arg(args, void __user *);
	va_end(args);

	trace_mark(xn_rtdm, ioctl, "user_info %p fd %d request %d arg %p",
		   user_info, fd, request, arg);

	MAJOR_FUNCTION_WRAPPER_TH(ioctl, (unsigned int)request, arg);

	if (unlikely(ret < 0) && (unsigned int)request == RTIOC_DEVICE_INFO) {
		struct rtdm_device *dev = context->device;
		struct rtdm_device_info dev_info;

		dev_info.device_flags = dev->device_flags;
		dev_info.device_class = dev->device_class;
		dev_info.device_sub_class = dev->device_sub_class;
		dev_info.profile_version = dev->profile_version;

		ret = rtdm_safe_copy_to_user(user_info, arg, &dev_info,
					     sizeof(dev_info));
	}

	MAJOR_FUNCTION_WRAPPER_BH();
}

EXPORT_SYMBOL(__rt_dev_ioctl);

ssize_t __rt_dev_read(rtdm_user_info_t *user_info, int fd, void *buf,
		      size_t nbyte)
{
	trace_mark(xn_rtdm, read, "user_info %p fd %d buf %p nbyte %zu",
		   user_info, fd, buf, nbyte);
	MAJOR_FUNCTION_WRAPPER(read, buf, nbyte);
}

EXPORT_SYMBOL(__rt_dev_read);

ssize_t __rt_dev_write(rtdm_user_info_t *user_info, int fd, const void *buf,
		       size_t nbyte)
{
	trace_mark(xn_rtdm, write, "user_info %p fd %d buf %p nbyte %zu",
		   user_info, fd, buf, nbyte);
	MAJOR_FUNCTION_WRAPPER(write, buf, nbyte);
}

EXPORT_SYMBOL(__rt_dev_write);

ssize_t __rt_dev_recvmsg(rtdm_user_info_t *user_info, int fd,
			 struct msghdr *msg, int flags)
{
	trace_mark(xn_rtdm, recvmsg, "user_info %p fd %d msg_name %p "
		   "msg_namelen %u msg_iov %p msg_iovlen %zu "
		   "msg_control %p msg_controllen %zu msg_flags %d",
		   user_info, fd, msg->msg_name, msg->msg_namelen,
		   msg->msg_iov, msg->msg_iovlen, msg->msg_control,
		   msg->msg_controllen, msg->msg_flags);
	MAJOR_FUNCTION_WRAPPER(recvmsg, msg, flags);
}

EXPORT_SYMBOL(__rt_dev_recvmsg);

ssize_t __rt_dev_sendmsg(rtdm_user_info_t *user_info, int fd,
			 const struct msghdr *msg, int flags)
{
	trace_mark(xn_rtdm, sendmsg, "user_info %p fd %d msg_name %p "
		   "msg_namelen %u msg_iov %p msg_iovlen %zu "
		   "msg_control %p msg_controllen %zu msg_flags %d",
		   user_info, fd, msg->msg_name, msg->msg_namelen,
		   msg->msg_iov, msg->msg_iovlen, msg->msg_control,
		   msg->msg_controllen, msg->msg_flags);
	MAJOR_FUNCTION_WRAPPER(sendmsg, msg, flags);
}

EXPORT_SYMBOL(__rt_dev_sendmsg);

/**
 * @brief Bind a selector to specified event types of a given file descriptor
 * @internal
 *
 * This function is invoked by higher RTOS layers implementing select-like
 * services. It shall not be called directly by RTDM drivers.
 *
 * @param[in] fd File descriptor to bind to
 * @param[in,out] selector Selector object that shall be bound to the given
 * event
 * @param[in] type Event type the caller is interested in
 * @param[in] fd_index Index in the file descriptor set of the caller
 *
 * @return 0 on success, otherwise:
 *
 * - -EBADF is returned if the file descriptor @a fd cannot be resolved.
 *
 * - -EINVAL is returned if @a type or @a fd_index are invalid.
 *
 * Environments:
 *
 * This service can be called from:
 *
 * - Kernel module initialization/cleanup code
 * - Kernel-based task
 * - User-space task (RT, non-RT)
 *
 * Rescheduling: never.
 */
int rtdm_select_bind(int fd, rtdm_selector_t *selector,
		     enum rtdm_selecttype type, unsigned fd_index)
{
	struct rtdm_dev_context *context;
	struct rtdm_operations  *ops;
	int ret;

	context = rtdm_context_get(fd);

	ret = -EBADF;
	if (unlikely(!context))
		goto err_out;

	ops = context->ops;

	ret = ops->select_bind(context, selector, type, fd_index);

	RTAI_ASSERT(RTDM, !rthal_local_irq_disabled(),
		    rthal_local_irq_enable(););

	rtdm_context_unlock(context);

  err_out:
	return ret;
}

EXPORT_SYMBOL(rtdm_select_bind);

#ifdef DOXYGEN_CPP /* Only used for doxygen doc generation */

/**
 * @brief Increment context reference counter
 *
 * @param[in] context Device context
 *
 * @note rtdm_context_get() automatically increments the lock counter. You
 * only need to call this function in special scenarios, e.g. when keeping
 * additional references to the context structure that have different
 * lifetimes. Only use rtdm_context_lock() on contexts that are currently
 * locked via an earlier rtdm_context_get()/rtdm_contex_lock() or while
 * running a device operation handler.
 *
 * Environments:
 *
 * This service can be called from:
 *
 * - Kernel module initialization/cleanup code
 * - Interrupt service routine
 * - Kernel-based task
 * - User-space task (RT, non-RT)
 *
 * Rescheduling: never.
 */
void rtdm_context_lock(struct rtdm_dev_context *context);

/**
 * @brief Decrement context reference counter
 *
 * @param[in] context Device context
 *
 * @note Every call to rtdm_context_locked() must be matched by a
 * rtdm_context_unlock() invocation.
 *
 * Environments:
 *
 * This service can be called from:
 *
 * - Kernel module initialization/cleanup code
 * - Interrupt service routine
 * - Kernel-based task
 * - User-space task (RT, non-RT)
 *
 * Rescheduling: never.
 */
void rtdm_context_unlock(struct rtdm_dev_context *context);

/**
 * @brief Release a device context obtained via rtdm_context_get()
 *
 * @param[in] context Device context
 *
 * @note Every successful call to rtdm_context_get() must be matched by a
 * rtdm_context_put() invocation.
 *
 * Environments:
 *
 * This service can be called from:
 *
 * - Kernel module initialization/cleanup code
 * - Interrupt service routine
 * - Kernel-based task
 * - User-space task (RT, non-RT)
 *
 * Rescheduling: never.
 */
void rtdm_context_put(struct rtdm_dev_context *context);

/**
 * @brief Open a device
 *
 * Refer to rt_dev_open() for parameters and return values
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 */
int rtdm_open(const char *path, int oflag, ...);

/**
 * @brief Create a socket
 *
 * Refer to rt_dev_socket() for parameters and return values
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 */
int rtdm_socket(int protocol_family, int socket_type, int protocol);

/**
 * @brief Close a device or socket
 *
 * Refer to rt_dev_close() for parameters and return values
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 */
int rtdm_close(int fd);

/**
 * @brief Issue an IOCTL
 *
 * Refer to rt_dev_ioctl() for parameters and return values
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 */
int rtdm_ioctl(int fd, int request, ...);

/**
 * @brief Read from device
 *
 * Refer to rt_dev_read() for parameters and return values
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 */
ssize_t rtdm_read(int fd, void *buf, size_t nbyte);

/**
 * @brief Write to device
 *
 * Refer to rt_dev_write() for parameters and return values
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 */
ssize_t rtdm_write(int fd, const void *buf, size_t nbyte);

/**
 * @brief Receive message from socket
 *
 * Refer to rt_dev_recvmsg() for parameters and return values
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 */
ssize_t rtdm_recvmsg(int fd, struct msghdr *msg, int flags);

/**
 * @brief Receive message from socket
 *
 * Refer to rt_dev_recvfrom() for parameters and return values
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 */
ssize_t rtdm_recvfrom(int fd, void *buf, size_t len, int flags,
		      struct sockaddr *from, socklen_t *fromlen);

/**
 * @brief Receive message from socket
 *
 * Refer to rt_dev_recv() for parameters and return values
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 */
ssize_t rtdm_recv(int fd, void *buf, size_t len, int flags);

/**
 * @brief Transmit message to socket
 *
 * Refer to rt_dev_sendmsg() for parameters and return values
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 */
ssize_t rtdm_sendmsg(int fd, const struct msghdr *msg, int flags);

/**
 * @brief Transmit message to socket
 *
 * Refer to rt_dev_sendto() for parameters and return values
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 */
ssize_t rtdm_sendto(int fd, const void *buf, size_t len, int flags,
		    const struct sockaddr *to, socklen_t tolen);

/**
 * @brief Transmit message to socket
 *
 * Refer to rt_dev_send() for parameters and return values
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 */
ssize_t rtdm_send(int fd, const void *buf, size_t len, int flags);

/**
 * @brief Bind to local address
 *
 * Refer to rt_dev_bind() for parameters and return values
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 */
int rtdm_bind(int fd, const struct sockaddr *my_addr, socklen_t addrlen);

/**
 * @brief Connect to remote address
 *
 * Refer to rt_dev_connect() for parameters and return values
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 */
int rtdm_connect(int fd, const struct sockaddr *serv_addr, socklen_t addrlen);

/**
 * @brief Listen for incomming connection requests
 *
 * Refer to rt_dev_listen() for parameters and return values
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 */
int rtdm_listen(int fd, int backlog);

/**
 * @brief Accept a connection requests
 *
 * Refer to rt_dev_accept() for parameters and return values
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 */
int rtdm_accept(int fd, struct sockaddr *addr, socklen_t *addrlen);

/**
 * @brief Shut down parts of a connection
 *
 * Refer to rt_dev_shutdown() for parameters and return values
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 */
int rtdm_shutdown(int fd, int how);

/**
 * @brief Get socket option
 *
 * Refer to rt_dev_getsockopt() for parameters and return values
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 */
int rtdm_getsockopt(int fd, int level, int optname, void *optval,
		    socklen_t *optlen);

/**
 * @brief Set socket option
 *
 * Refer to rt_dev_setsockopt() for parameters and return values
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 */
int rtdm_setsockopt(int fd, int level, int optname, const void *optval,
		    socklen_t optlen);

/**
 * @brief Get local socket address
 *
 * Refer to rt_dev_getsockname() for parameters and return values
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 */
int rtdm_getsockname(int fd, struct sockaddr *name, socklen_t *namelen);

/**
 * @brief Get socket destination address
 *
 * Refer to rt_dev_getpeername() for parameters and return values
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 */
int rtdm_getpeername(int fd, struct sockaddr *name, socklen_t *namelen);

/** @} */

/*!
 * @addtogroup userapi
 * @{
 */

/**
 * @brief Open a device
 *
 * @param[in] path Device name
 * @param[in] oflag Open flags
 * @param ... Further parameters will be ignored.
 *
 * @return Positive file descriptor value on success, otherwise a negative
 * error code.
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 *
 * @see @c open() in IEEE Std 1003.1,
 * http://www.opengroup.org/onlinepubs/009695399
 */
int rt_dev_open(const char *path, int oflag, ...);

/**
 * @brief Create a socket
 *
 * @param[in] protocol_family Protocol family (@c PF_xxx)
 * @param[in] socket_type Socket type (@c SOCK_xxx)
 * @param[in] protocol Protocol ID, 0 for default
 *
 * @return Positive file descriptor value on success, otherwise a negative
 * error code.
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 *
 * @see @c socket() in IEEE Std 1003.1,
 * http://www.opengroup.org/onlinepubs/009695399
 */
int rt_dev_socket(int protocol_family, int socket_type, int protocol);

/**
 * @brief Close a device or socket
 *
 * @param[in] fd File descriptor as returned by rt_dev_open() or rt_dev_socket()
 *
 * @return 0 on success, otherwise a negative error code.
 *
 * @note If the matching rt_dev_open() or rt_dev_socket() call took place in
 * non-real-time context, rt_dev_close() must be issued within non-real-time
 * as well. Otherwise, the call will fail.
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 *
 * @see @c close() in IEEE Std 1003.1,
 * http://www.opengroup.org/onlinepubs/009695399
 */
int rt_dev_close(int fd);

/**
 * @brief Issue an IOCTL
 *
 * @param[in] fd File descriptor as returned by rt_dev_open() or rt_dev_socket()
 * @param[in] request IOCTL code
 * @param ... Optional third argument, depending on IOCTL function
 * (@c void @c * or @c unsigned @c long)
 *
 * @return Positiv value on success, otherwise negative error code
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 *
 * @see @c ioctl() in IEEE Std 1003.1,
 * http://www.opengroup.org/onlinepubs/009695399
 */
int rt_dev_ioctl(int fd, int request, ...);

/**
 * @brief Read from device
 *
 * @param[in] fd File descriptor as returned by rt_dev_open()
 * @param[out] buf Input buffer
 * @param[in] nbyte Number of bytes to read
 *
 * @return Number of bytes read, otherwise negative error code
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 *
 * @see @c read() in IEEE Std 1003.1,
 * http://www.opengroup.org/onlinepubs/009695399
 */
ssize_t rt_dev_read(int fd, void *buf, size_t nbyte);

/**
 * @brief Write to device
 *
 * @param[in] fd File descriptor as returned by rt_dev_open()
 * @param[in] buf Output buffer
 * @param[in] nbyte Number of bytes to write
 *
 * @return Number of bytes written, otherwise negative error code
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 *
 * @see @c write() in IEEE Std 1003.1,
 * http://www.opengroup.org/onlinepubs/009695399
 */
ssize_t rt_dev_write(int fd, const void *buf, size_t nbyte);

/**
 * @brief Receive message from socket
 *
 * @param[in] fd File descriptor as returned by rt_dev_socket()
 * @param[in,out] msg Message descriptor
 * @param[in] flags Message flags
 *
 * @return Number of bytes received, otherwise negative error code
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 *
 * @see @c recvmsg() in IEEE Std 1003.1,
 * http://www.opengroup.org/onlinepubs/009695399
 */
ssize_t rt_dev_recvmsg(int fd, struct msghdr *msg, int flags);

/**
 * @brief Receive message from socket
 *
 * @param[in] fd File descriptor as returned by rt_dev_socket()
 * @param[out] buf Message buffer
 * @param[in] len Message buffer size
 * @param[in] flags Message flags
 * @param[out] from Buffer for message sender address
 * @param[in,out] fromlen Address buffer size
 *
 * @return Number of bytes received, otherwise negative error code
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 *
 * @see @c recvfrom() in IEEE Std 1003.1,
 * http://www.opengroup.org/onlinepubs/009695399
 */
ssize_t rt_dev_recvfrom(int fd, void *buf, size_t len, int flags,
			struct sockaddr *from, socklen_t *fromlen);

/**
 * @brief Receive message from socket
 *
 * @param[in] fd File descriptor as returned by rt_dev_socket()
 * @param[out] buf Message buffer
 * @param[in] len Message buffer size
 * @param[in] flags Message flags
 *
 * @return Number of bytes received, otherwise negative error code
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 *
 * @see @c recv() in IEEE Std 1003.1,
 * http://www.opengroup.org/onlinepubs/009695399
 */
ssize_t rt_dev_recv(int fd, void *buf, size_t len, int flags);

/**
 * @brief Transmit message to socket
 *
 * @param[in] fd File descriptor as returned by rt_dev_socket()
 * @param[in] msg Message descriptor
 * @param[in] flags Message flags
 *
 * @return Number of bytes sent, otherwise negative error code
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 *
 * @see @c sendmsg() in IEEE Std 1003.1,
 * http://www.opengroup.org/onlinepubs/009695399
 */
ssize_t rt_dev_sendmsg(int fd, const struct msghdr *msg, int flags);

/**
 * @brief Transmit message to socket
 *
 * @param[in] fd File descriptor as returned by rt_dev_socket()
 * @param[in] buf Message buffer
 * @param[in] len Message buffer size
 * @param[in] flags Message flags
 * @param[in] to Buffer for message destination address
 * @param[in] tolen Address buffer size
 *
 * @return Number of bytes sent, otherwise negative error code
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 *
 * @see @c sendto() in IEEE Std 1003.1,
 * http://www.opengroup.org/onlinepubs/009695399
 */
ssize_t rt_dev_sendto(int fd, const void *buf, size_t len, int flags,
		      const struct sockaddr *to, socklen_t tolen);

/**
 * @brief Transmit message to socket
 *
 * @param[in] fd File descriptor as returned by rt_dev_socket()
 * @param[in] buf Message buffer
 * @param[in] len Message buffer size
 * @param[in] flags Message flags
 *
 * @return Number of bytes sent, otherwise negative error code
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 *
 * @see @c send() in IEEE Std 1003.1,
 * http://www.opengroup.org/onlinepubs/009695399
 */
ssize_t rt_dev_send(int fd, const void *buf, size_t len, int flags);

/**
 * @brief Bind to local address
 *
 * @param[in] fd File descriptor as returned by rt_dev_socket()
 * @param[in] my_addr Address buffer
 * @param[in] addrlen Address buffer size
 *
 * @return 0 on success, otherwise negative error code
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 *
 * @see @c bind() in IEEE Std 1003.1,
 * http://www.opengroup.org/onlinepubs/009695399
 */
int rt_dev_bind(int fd, const struct sockaddr *my_addr, socklen_t addrlen);

/**
 * @brief Connect to remote address
 *
 * @param[in] fd File descriptor as returned by rt_dev_socket()
 * @param[in] serv_addr Address buffer
 * @param[in] addrlen Address buffer size
 *
 * @return 0 on success, otherwise negative error code
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 *
 * @see @c connect() in IEEE Std 1003.1,
 * http://www.opengroup.org/onlinepubs/009695399
 */
int rt_dev_connect(int fd, const struct sockaddr *serv_addr,
		   socklen_t addrlen);

/**
 * @brief Listen for incomming connection requests
 *
 * @param[in] fd File descriptor as returned by rt_dev_socket()
 * @param[in] backlog Maximum queue length
 *
 * @return 0 on success, otherwise negative error code
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 *
 * @see @c lsiten() in IEEE Std 1003.1,
 * http://www.opengroup.org/onlinepubs/009695399
 */
int rt_dev_listen(int fd, int backlog);

/**
 * @brief Accept a connection requests
 *
 * @param[in] fd File descriptor as returned by rt_dev_socket()
 * @param[out] addr Buffer for remote address
 * @param[in,out] addrlen Address buffer size
 *
 * @return 0 on success, otherwise negative error code
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 *
 * @see @c accept() in IEEE Std 1003.1,
 * http://www.opengroup.org/onlinepubs/009695399
 */
int rt_dev_accept(int fd, struct sockaddr *addr, socklen_t *addrlen);

/**
 * @brief Shut down parts of a connection
 *
 * @param[in] fd File descriptor as returned by rt_dev_socket()
 * @param[in] how Specifies the part to be shut down (@c SHUT_xxx)
*
 * @return 0 on success, otherwise negative error code
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 *
 * @see @c shutdown() in IEEE Std 1003.1,
 * http://www.opengroup.org/onlinepubs/009695399
 */
int rt_dev_shutdown(int fd, int how);

/**
 * @brief Get socket option
 *
 * @param[in] fd File descriptor as returned by rt_dev_socket()
 * @param[in] level Addressed stack level
 * @param[in] optname Option name ID
 * @param[out] optval Value buffer
 * @param[in,out] optlen Value buffer size
 *
 * @return 0 on success, otherwise negative error code
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 *
 * @see @c getsockopt() in IEEE Std 1003.1,
 * http://www.opengroup.org/onlinepubs/009695399
 */
int rt_dev_getsockopt(int fd, int level, int optname, void *optval,
		      socklen_t *optlen);

/**
 * @brief Set socket option
 *
 * @param[in] fd File descriptor as returned by rt_dev_socket()
 * @param[in] level Addressed stack level
 * @param[in] optname Option name ID
 * @param[in] optval Value buffer
 * @param[in] optlen Value buffer size
 *
 * @return 0 on success, otherwise negative error code
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 *
 * @see @c setsockopt() in IEEE Std 1003.1,
 * http://www.opengroup.org/onlinepubs/009695399
 */
int rt_dev_setsockopt(int fd, int level, int optname, const void *optval,
		      socklen_t optlen);

/**
 * @brief Get local socket address
 *
 * @param[in] fd File descriptor as returned by rt_dev_socket()
 * @param[out] name Address buffer
 * @param[in,out] namelen Address buffer size
 *
 * @return 0 on success, otherwise negative error code
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 *
 * @see @c getsockname() in IEEE Std 1003.1,
 * http://www.opengroup.org/onlinepubs/009695399
 */
int rt_dev_getsockname(int fd, struct sockaddr *name, socklen_t *namelen);

/**
 * @brief Get socket destination address
 *
 * @param[in] fd File descriptor as returned by rt_dev_socket()
 * @param[out] name Address buffer
 * @param[in,out] namelen Address buffer size
 *
 * @return 0 on success, otherwise negative error code
 *
 * Environments:
 *
 * Depends on driver implementation, see @ref profiles "Device Profiles".
 *
 * Rescheduling: possible.
 *
 * @see @c getpeername() in IEEE Std 1003.1,
 * http://www.opengroup.org/onlinepubs/009695399
 */
int rt_dev_getpeername(int fd, struct sockaddr *name, socklen_t *namelen);
/** @} */

#endif /* DOXYGEN_CPP */

#ifdef CONFIG_RTAI_RTDM_SELECT

/*
 RTAI extension to use select as any other usual RTDM rt_dev_xxx service.
 At the moment selector kept and stack, initialised/destroyed at each call.
 Usage is as for: 
 int rt_dev_select(int nfds, fd_set *rfds, fd_set *wfds, fd_set *efds,
                   nanosecs_rel_t timeout);.
 As it can be seen args are as for the standard select call execpt for the
 timout which is in nanos, in place of timespec.
*/

#define SELECT_DIM  XNSELECT_MAX_TYPES

/*
RTDM_FD_START kept in case we'll ever need a shift for fd being different from 
fd_index in the call to:
int rtdm_select_bind(int fd, rtdm_selector_t *selector, enum rtdm_selecttype type, unsigned fd_index);
*/

#define RTDM_FD_START  0

int __rt_dev_select(int nfds, fd_set *rfds, fd_set *wfds, fd_set *efds, nanosecs_rel_t timeout, struct xnselector *selector, int space)
{
	int i, fd, ret;
	fd_set *fds[SELECT_DIM] = { rfds, wfds, efds };
	fd_set *reqp[SELECT_DIM], req[SELECT_DIM];
	fd_set *resp[SELECT_DIM], res[SELECT_DIM];
	fd_set **bp, *cp;

	for (ret = i = 0; i < SELECT_DIM; i++) {
		if (fds[i] && find_first_bit(fds[i]->fds_bits, nfds) < nfds) {
			ret = 1;
			reqp[i] = &req[i];
			resp[i] = &res[i];
			if (space) {
				memcpy((void *)reqp[i], (void *)fds[i], __FDELT__(nfds + __NFDBITS__ - 1)*sizeof(long));
			} else {
				rt_copy_from_user((void *)reqp[i], (void *)fds[i], __FDELT__(nfds + __NFDBITS__ - 1)*sizeof(long));
			}
		} else {
			reqp[i] = resp[i] = NULL;
		}
	}

	if (!ret && !timeout) {
		return -EINVAL;
	}

	if (timeout) {
		timeout = rt_get_time() + nano2count(timeout);
	}

	do {
		for (bp = reqp, i = 0; i < SELECT_DIM; i++) {
			if ((cp = bp[i])) {
				for (fd = find_first_bit(cp->fds_bits, nfds); fd < nfds; fd = find_next_bit(cp->fds_bits, nfds, fd + 1)) {
					if ((ret = rtdm_select_bind(fd - RTDM_FD_START, selector, i, fd))) {
						return ret;
					}
				}
			}
		}
		bp = resp;
		ret = xnselect(selector, resp, reqp, nfds, timeout, XN_ABSOLUTE);
	} while (ret == -ECHRNG);

	if (ret > 0) {
		for (i = 0; i < SELECT_DIM; i++) {
			if (fds[i]) {
				if (space) {
					memcpy((void *)fds[i], (void *)resp[i], sizeof(fd_set));
				} else {
					rt_copy_to_user((void *)fds[i], (void *)resp[i], sizeof(fd_set));
				}
			}
		}
	}
	return ret;
}

EXPORT_SYMBOL(__rt_dev_select);

#endif