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/*
* File : pipe.c
* This file is part of RT-Thread RTOS
* COPYRIGHT (C) 2012, RT-Thread Development Team
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rt-thread.org/license/LICENSE
*
* Change Logs:
* Date Author Notes
* 2012-09-30 Bernard first version.
*/
#include <rthw.h>
#include <rtthread.h>
#include <rtdevice.h>
static rt_size_t rt_pipe_read(rt_device_t dev,
rt_off_t pos,
void *buffer,
rt_size_t size)
{
rt_uint32_t level;
rt_thread_t thread;
struct rt_pipe_device *pipe;
rt_size_t read_nbytes;
pipe = PIPE_DEVICE(dev);
RT_ASSERT(pipe != RT_NULL);
thread = rt_thread_self();
/* current context checking */
RT_DEBUG_NOT_IN_INTERRUPT;
do
{
level = rt_hw_interrupt_disable();
read_nbytes = rt_ringbuffer_get(&(pipe->ringbuffer), buffer, size);
if (read_nbytes == 0)
{
rt_thread_suspend(thread);
/* waiting on suspended read list */
rt_list_insert_before(&(pipe->suspended_read_list),
&(thread->tlist));
rt_hw_interrupt_enable(level);
rt_schedule();
}
else
{
if (!rt_list_isempty(&pipe->suspended_write_list))
{
/* get suspended thread */
thread = rt_list_entry(pipe->suspended_write_list.next,
struct rt_thread,
tlist);
/* resume the write thread */
rt_thread_resume(thread);
rt_hw_interrupt_enable(level);
rt_schedule();
}
else
{
rt_hw_interrupt_enable(level);
}
break;
}
} while (read_nbytes == 0);
return read_nbytes;
}
struct rt_pipe_device *_pipe = RT_NULL;
static rt_size_t rt_pipe_write(rt_device_t dev,
rt_off_t pos,
const void *buffer,
rt_size_t size)
{
rt_uint32_t level;
rt_thread_t thread;
struct rt_pipe_device *pipe;
rt_size_t write_nbytes;
pipe = PIPE_DEVICE(dev);
RT_ASSERT(pipe != RT_NULL);
if (_pipe == RT_NULL)
_pipe = pipe;
thread = rt_thread_self();
/* current context checking */
RT_DEBUG_NOT_IN_INTERRUPT;
do
{
level = rt_hw_interrupt_disable();
write_nbytes = rt_ringbuffer_put(&(pipe->ringbuffer), buffer, size);
if (write_nbytes == 0)
{
/* pipe full, waiting on suspended write list */
rt_thread_suspend(thread);
/* waiting on suspended read list */
rt_list_insert_before(&(pipe->suspended_write_list),
&(thread->tlist));
rt_hw_interrupt_enable(level);
rt_schedule();
}
else
{
if (!rt_list_isempty(&pipe->suspended_read_list))
{
/* get suspended thread */
thread = rt_list_entry(pipe->suspended_read_list.next,
struct rt_thread,
tlist);
/* resume the read thread */
rt_thread_resume(thread);
rt_hw_interrupt_enable(level);
rt_schedule();
}
else
{
rt_hw_interrupt_enable(level);
}
break;
}
}while (write_nbytes == 0);
return write_nbytes;
}
static rt_err_t rt_pipe_control(rt_device_t dev, rt_uint8_t cmd, void *args)
{
return RT_EOK;
}
rt_err_t rt_pipe_create(const char *name, rt_size_t size)
{
rt_err_t result = RT_EOK;
rt_uint8_t *rb_memptr = RT_NULL;
struct rt_pipe_device *pipe = RT_NULL;
/* get aligned size */
size = RT_ALIGN(size, RT_ALIGN_SIZE);
pipe = (struct rt_pipe_device *)rt_calloc(1, sizeof(struct rt_pipe_device));
if (pipe != RT_NULL)
{
/* create ring buffer of pipe */
rb_memptr = rt_malloc(size);
if (rb_memptr == RT_NULL)
{
result = -RT_ENOMEM;
goto __exit;
}
/* initialize suspended list */
rt_list_init(&pipe->suspended_read_list);
rt_list_init(&pipe->suspended_write_list);
/* initialize ring buffer */
rt_ringbuffer_init(&pipe->ringbuffer, rb_memptr, size);
/* create device */
pipe->parent.type = RT_Device_Class_Char;
pipe->parent.init = RT_NULL;
pipe->parent.open = RT_NULL;
pipe->parent.close = RT_NULL;
pipe->parent.read = rt_pipe_read;
pipe->parent.write = rt_pipe_write;
pipe->parent.control = rt_pipe_control;
return rt_device_register(&(pipe->parent), name, RT_DEVICE_FLAG_RDWR);
}
else
{
result = -RT_ENOMEM;
}
__exit:
if (pipe != RT_NULL)
rt_free(pipe);
if (rb_memptr != RT_NULL)
rt_free(rb_memptr);
return result;
}
RTM_EXPORT(rt_pipe_create);
void rt_pipe_destroy(struct rt_pipe_device *pipe)
{
if (pipe == RT_NULL)
return;
/* un-register pipe device */
rt_device_unregister(&(pipe->parent));
/* release memory */
rt_free(pipe->ringbuffer.buffer_ptr);
rt_free(pipe);
return;
}
RTM_EXPORT(rt_pipe_destroy);
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