forked from Imagelibrary/rtems
d50acdbb6c
Add a local context structure to the SMP lock API for acquire and release pairs. This context can be used to store the ISR level and profiling information. It may be later used to enable more sophisticated lock algorithms, e.g. MCS locks. There is only one lock that cannot be used with a local context. This is the per-CPU lock since here we would have to transfer the local context through a context switch which is very complicated.
58 lines
1.5 KiB
C
58 lines
1.5 KiB
C
/**
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* @file
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*
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* @brief Simple Ring Buffer Functionality
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*
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* This file provides simple ring buffer functionality.
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*/
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#ifndef _RTEMS_RINGBUF_H
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#define _RTEMS_RINGBUF_H
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#include <rtems.h>
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#ifndef RINGBUF_QUEUE_LENGTH
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#define RINGBUF_QUEUE_LENGTH 128
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#endif
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typedef struct {
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uint8_t buffer[RINGBUF_QUEUE_LENGTH];
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volatile int head;
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volatile int tail;
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rtems_interrupt_lock lock;
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} Ring_buffer_t;
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#define Ring_buffer_Initialize( _buffer ) \
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do { \
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(_buffer)->head = (_buffer)->tail = 0; \
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} while ( 0 )
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#define Ring_buffer_Is_empty( _buffer ) \
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( (_buffer)->head == (_buffer)->tail )
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#define Ring_buffer_Is_full( _buffer ) \
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( (_buffer)->head == ((_buffer)->tail + 1) % RINGBUF_QUEUE_LENGTH )
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#define Ring_buffer_Add_character( _buffer, _ch ) \
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do { \
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rtems_interrupt_lock_context lock_context; \
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\
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rtems_interrupt_lock_acquire( &(_buffer)->lock, &lock_context ); \
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(_buffer)->tail = ((_buffer)->tail+1) % RINGBUF_QUEUE_LENGTH; \
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(_buffer)->buffer[ (_buffer)->tail ] = (_ch); \
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rtems_interrupt_lock_release( &(_buffer)->lock, &lock_context ); \
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} while ( 0 )
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#define Ring_buffer_Remove_character( _buffer, _ch ) \
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do { \
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rtems_interrupt_lock_context lock_context; \
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\
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rtems_interrupt_lock_acquire( &(_buffer)->lock, &lock_context ); \
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(_buffer)->head = ((_buffer)->head+1) % RINGBUF_QUEUE_LENGTH; \
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(_ch) = (_buffer)->buffer[ (_buffer)->head ]; \
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rtems_interrupt_lock_release( &(_buffer)->lock, &lock_context ); \
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} while ( 0 )
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#endif
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