device.c

/*
 * File      : device.c
 * This file is part of RT-Thread RTOS
 * COPYRIGHT (C) 2006 - 2013, RT-Thread Development Team
 *
 *  This program 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.
 *
 *  This program 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 this program; if not, write to the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Change Logs:
 * Date           Author       Notes
 * 2007-01-21     Bernard      the first version
 * 2010-05-04     Bernard      add rt_device_init implementation
 * 2012-10-20     Bernard      add device check in register function,
 *                             provided by Rob <rdent@iinet.net.au>
 * 2012-12-25     Bernard      return RT_EOK if the device interface not exist.
 * 2013-07-09     Grissiom     add ref_count support
 */

#include <rtthread.h>

#ifdef RT_USING_DEVICE

/**
 * This function registers a device driver with specified name.
 *
 * @param dev the pointer of device driver structure
 * @param name the device driver's name
 * @param flags the flag of device
 *
 * @return the error code, RT_EOK on initialization successfully.
 */
rt_err_t rt_device_register(rt_device_t dev,
                            const char *name,
                            rt_uint16_t flags)
{
    if (dev == RT_NULL)
        return -RT_ERROR;

    if (rt_device_find(name) != RT_NULL)
        return -RT_ERROR;

    rt_object_init(&(dev->parent), RT_Object_Class_Device, name);
    dev->flag = flags;
    dev->ref_count = 0;

    return RT_EOK;
}
RTM_EXPORT(rt_device_register);

/**
 * This function removes a previously registered device driver
 *
 * @param dev the pointer of device driver structure
 *
 * @return the error code, RT_EOK on successfully.
 */
rt_err_t rt_device_unregister(rt_device_t dev)
{
    RT_ASSERT(dev != RT_NULL);

    rt_object_detach(&(dev->parent));

    return RT_EOK;
}
RTM_EXPORT(rt_device_unregister);

/**
 * This function initializes all registered device driver
 *
 * @return the error code, RT_EOK on successfully.
 *
 * @deprecated since 1.2.x, this function is not needed because the initialization 
 *             of a device is performed when applicaiton opens it.
 */
rt_err_t rt_device_init_all(void)
{
    return RT_EOK;
}

/**
 * This function finds a device driver by specified name.
 *
 * @param name the device driver's name
 *
 * @return the registered device driver on successful, or RT_NULL on failure.
 */
rt_device_t rt_device_find(const char *name)
{
    struct rt_object *object;
    struct rt_list_node *node;
    struct rt_object_information *information;

    extern struct rt_object_information rt_object_container[];

    /* enter critical */
    if (rt_thread_self() != RT_NULL)
        rt_enter_critical();

    /* try to find device object */
    information = &rt_object_container[RT_Object_Class_Device];
    for (node  = information->object_list.next;
         node != &(information->object_list);
         node  = node->next)
    {
        object = rt_list_entry(node, struct rt_object, list);
        if (rt_strncmp(object->name, name, RT_NAME_MAX) == 0)
        {
            /* leave critical */
            if (rt_thread_self() != RT_NULL)
                rt_exit_critical();

            return (rt_device_t)object;
        }
    }

    /* leave critical */
    if (rt_thread_self() != RT_NULL)
        rt_exit_critical();

    /* not found */
    return RT_NULL;
}
RTM_EXPORT(rt_device_find);

/**
 * This function will initialize the specified device
 *
 * @param dev the pointer of device driver structure
 *
 * @return the result
 */
rt_err_t rt_device_init(rt_device_t dev)
{
    rt_err_t result = RT_EOK;

    RT_ASSERT(dev != RT_NULL);

    /* get device init handler */
    if (dev->init != RT_NULL)
    {
        if (!(dev->flag & RT_DEVICE_FLAG_ACTIVATED))
        {
            result = dev->init(dev);
            if (result != RT_EOK)
            {
                rt_kprintf("To initialize device:%s failed. The error code is %d\n",
                           dev->parent.name, result);
            }
            else
            {
                dev->flag |= RT_DEVICE_FLAG_ACTIVATED;
            }
        }
    }

    return result;
}

/**
 * This function will open a device
 *
 * @param dev the pointer of device driver structure
 * @param oflag the flags for device open
 *
 * @return the result
 */
rt_err_t rt_device_open(rt_device_t dev, rt_uint16_t oflag)
{
    rt_err_t result = RT_EOK;

    RT_ASSERT(dev != RT_NULL);

    /* if device is not initialized, initialize it. */
    if (!(dev->flag & RT_DEVICE_FLAG_ACTIVATED))
    {
        if (dev->init != RT_NULL)
        {
            result = dev->init(dev);
            if (result != RT_EOK)
            {
                rt_kprintf("To initialize device:%s failed. The error code is %d\n",
                           dev->parent.name, result);

                return result;
            }
        }

        dev->flag |= RT_DEVICE_FLAG_ACTIVATED;
    }

    /* device is a stand alone device and opened */
    if ((dev->flag & RT_DEVICE_FLAG_STANDALONE) &&
        (dev->open_flag & RT_DEVICE_OFLAG_OPEN))
    {
        return -RT_EBUSY;
    }

    /* call device open interface */
    if (dev->open != RT_NULL)
    {
        result = dev->open(dev, oflag);
    }

    /* set open flag */
    if (result == RT_EOK || result == -RT_ENOSYS)
    {
        dev->open_flag = oflag | RT_DEVICE_OFLAG_OPEN;

        dev->ref_count++;
        /* don't let bad things happen silently. If you are bitten by this assert,
         * please set the ref_count to a bigger type. */
        RT_ASSERT(dev->ref_count != 0);
    }

    return result;
}
RTM_EXPORT(rt_device_open);

/**
 * This function will close a device
 *
 * @param dev the pointer of device driver structure
 *
 * @return the result
 */
rt_err_t rt_device_close(rt_device_t dev)
{
    rt_err_t result = RT_EOK;

    RT_ASSERT(dev != RT_NULL);

    if (dev->ref_count == 0)
        return -RT_ERROR;

    dev->ref_count--;

    if (dev->ref_count != 0)
        return RT_EOK;

    /* call device close interface */
    if (dev->close != RT_NULL)
    {
        result = dev->close(dev);
    }

    /* set open flag */
    if (result == RT_EOK || result == -RT_ENOSYS)
        dev->open_flag = RT_DEVICE_OFLAG_CLOSE;

    return result;
}
RTM_EXPORT(rt_device_close);

/**
 * This function will read some data from a device.
 *
 * @param dev the pointer of device driver structure
 * @param pos the position of reading
 * @param buffer the data buffer to save read data
 * @param size the size of buffer
 *
 * @return the actually read size on successful, otherwise negative returned.
 *
 * @note since 0.4.0, the unit of size/pos is a block for block device.
 */
rt_size_t rt_device_read(rt_device_t dev,
                         rt_off_t    pos,
                         void       *buffer,
                         rt_size_t   size)
{
    RT_ASSERT(dev != RT_NULL);

    if (dev->ref_count == 0)
    {
        rt_set_errno(-RT_ERROR);
        return 0;
    }

    /* call device read interface */
    if (dev->read != RT_NULL)
    {
        return dev->read(dev, pos, buffer, size);
    }

    /* set error code */
    rt_set_errno(-RT_ENOSYS);

    return 0;
}
RTM_EXPORT(rt_device_read);

/**
 * This function will write some data to a device.
 *
 * @param dev the pointer of device driver structure
 * @param pos the position of written
 * @param buffer the data buffer to be written to device
 * @param size the size of buffer
 *
 * @return the actually written size on successful, otherwise negative returned.
 *
 * @note since 0.4.0, the unit of size/pos is a block for block device.
 */
rt_size_t rt_device_write(rt_device_t dev,
                          rt_off_t    pos,
                          const void *buffer,
                          rt_size_t   size)
{
    RT_ASSERT(dev != RT_NULL);

    if (dev->ref_count == 0)
    {
        rt_set_errno(-RT_ERROR);
        return 0;
    }

    /* call device write interface */
    if (dev->write != RT_NULL)
    {
        return dev->write(dev, pos, buffer, size);
    }

    /* set error code */
    rt_set_errno(-RT_ENOSYS);

    return 0;
}
RTM_EXPORT(rt_device_write);

/**
 * This function will perform a variety of control functions on devices.
 *
 * @param dev the pointer of device driver structure
 * @param cmd the command sent to device
 * @param arg the argument of command
 *
 * @return the result
 */
rt_err_t rt_device_control(rt_device_t dev, rt_uint8_t cmd, void *arg)
{
    RT_ASSERT(dev != RT_NULL);

    /* call device write interface */
    if (dev->control != RT_NULL)
    {
        return dev->control(dev, cmd, arg);
    }

    return RT_EOK;
}
RTM_EXPORT(rt_device_control);

/**
 * This function will set the reception indication callback function. This callback function
 * is invoked when this device receives data.
 *
 * @param dev the pointer of device driver structure
 * @param rx_ind the indication callback function
 *
 * @return RT_EOK
 */
rt_err_t
rt_device_set_rx_indicate(rt_device_t dev,
                          rt_err_t (*rx_ind)(rt_device_t dev, rt_size_t size))
{
    RT_ASSERT(dev != RT_NULL);

    dev->rx_indicate = rx_ind;

    return RT_EOK;
}
RTM_EXPORT(rt_device_set_rx_indicate);

/**
 * This function will set the indication callback function when device has
 * written data to physical hardware.
 *
 * @param dev the pointer of device driver structure
 * @param tx_done the indication callback function
 *
 * @return RT_EOK
 */
rt_err_t
rt_device_set_tx_complete(rt_device_t dev,
                          rt_err_t (*tx_done)(rt_device_t dev, void *buffer))
{
    RT_ASSERT(dev != RT_NULL);

    dev->tx_complete = tx_done;

    return RT_EOK;
}
RTM_EXPORT(rt_device_set_tx_complete);

#endif