448 lines
13 KiB
C
448 lines
13 KiB
C
/*
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* File : scheduler.c
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* This file is part of RT-Thread RTOS
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* COPYRIGHT (C) 2006 - 2012, RT-Thread Development Team
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*
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* The license and distribution terms for this file may be
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* found in the file LICENSE in this distribution or at
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* http://www.rt-thread.org/license/LICENSE
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*
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* Change Logs:
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* Date Author Notes
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* 2006-03-17 Bernard the first version
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* 2006-04-28 Bernard fix the scheduler algorthm
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* 2006-04-30 Bernard add SCHEDULER_DEBUG
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* 2006-05-27 Bernard fix the scheduler algorthm for same priority
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* thread schedule
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* 2006-06-04 Bernard rewrite the scheduler algorithm
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* 2006-08-03 Bernard add hook support
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* 2006-09-05 Bernard add 32 priority level support
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* 2006-09-24 Bernard add rt_system_scheduler_start function
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* 2009-09-16 Bernard fix _rt_scheduler_stack_check
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* 2010-04-11 yi.qiu add module feature
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* 2010-07-13 Bernard fix the maximal number of rt_scheduler_lock_nest
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* issue found by kuronca
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* 2010-12-13 Bernard add defunct list initialization even if not use heap.
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* 2011-05-10 Bernard clean scheduler debug log.
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*/
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#include <rtthread.h>
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#include <rthw.h>
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static rt_int16_t rt_scheduler_lock_nest;
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extern volatile rt_uint8_t rt_interrupt_nest;
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rt_list_t rt_thread_priority_table[RT_THREAD_PRIORITY_MAX];
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struct rt_thread *rt_current_thread;
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rt_uint8_t rt_current_priority;
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#if RT_THREAD_PRIORITY_MAX > 32
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/* Maximum priority level, 256 */
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rt_uint32_t rt_thread_ready_priority_group;
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rt_uint8_t rt_thread_ready_table[32];
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#else
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/* Maximum priority level, 32 */
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rt_uint32_t rt_thread_ready_priority_group;
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#endif
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rt_list_t rt_thread_defunct;
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const rt_uint8_t rt_lowest_bitmap[] =
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{
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/* 00 */ 0, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
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/* 10 */ 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
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/* 20 */ 5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
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/* 30 */ 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
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/* 40 */ 6, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
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/* 50 */ 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
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/* 60 */ 5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
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/* 70 */ 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
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/* 80 */ 7, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
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/* 90 */ 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
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/* A0 */ 5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
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/* B0 */ 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
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/* C0 */ 6, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
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/* D0 */ 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
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/* E0 */ 5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
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/* F0 */ 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0
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};
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#ifdef RT_USING_HOOK
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static void (*rt_scheduler_hook)(struct rt_thread *from, struct rt_thread *to);
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/**
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* @addtogroup Hook
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*/
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/*@{*/
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/**
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* This function will set a hook function, which will be invoked when thread
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* switch happens.
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*
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* @param hook the hook function
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*/
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void
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rt_scheduler_sethook(void (*hook)(struct rt_thread *from, struct rt_thread *to))
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{
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rt_scheduler_hook = hook;
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}
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/*@}*/
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#endif
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#ifdef RT_USING_OVERFLOW_CHECK
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static void _rt_scheduler_stack_check(struct rt_thread *thread)
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{
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RT_ASSERT(thread != RT_NULL);
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if ((rt_uint32_t)thread->sp <= (rt_uint32_t)thread->stack_addr ||
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(rt_uint32_t)thread->sp >
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(rt_uint32_t)thread->stack_addr + (rt_uint32_t)thread->stack_size)
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{
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rt_uint32_t level;
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rt_kprintf("thread:%s stack overflow\n", thread->name);
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#ifdef RT_USING_FINSH
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{
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extern long list_thread(void);
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list_thread();
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}
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#endif
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level = rt_hw_interrupt_disable();
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while (level);
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}
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else if ((rt_uint32_t)thread->sp <= ((rt_uint32_t)thread->stack_addr + 32))
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{
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rt_kprintf("warning: %s stack is close to end of stack address.\n",
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thread->name);
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}
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}
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#endif
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/**
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* @ingroup SystemInit
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* This function will initialize the system scheduler
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*/
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void rt_system_scheduler_init(void)
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{
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register rt_base_t offset;
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rt_scheduler_lock_nest = 0;
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RT_DEBUG_LOG(RT_DEBUG_SCHEDULER, ("start scheduler: max priority 0x%02x\n",
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RT_THREAD_PRIORITY_MAX));
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for (offset = 0; offset < RT_THREAD_PRIORITY_MAX; offset ++)
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{
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rt_list_init(&rt_thread_priority_table[offset]);
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}
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rt_current_priority = RT_THREAD_PRIORITY_MAX - 1;
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rt_current_thread = RT_NULL;
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/* initialize ready priority group */
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rt_thread_ready_priority_group = 0;
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#if RT_THREAD_PRIORITY_MAX > 32
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/* initialize ready table */
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rt_memset(rt_thread_ready_table, 0, sizeof(rt_thread_ready_table));
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#endif
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/* initialize thread defunct */
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rt_list_init(&rt_thread_defunct);
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}
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/**
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* @ingroup SystemInit
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* This function will startup scheduler. It will select one thread
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* with the highest priority level, then switch to it.
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*/
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void rt_system_scheduler_start(void)
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{
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register struct rt_thread *to_thread;
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register rt_ubase_t highest_ready_priority;
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#if RT_THREAD_PRIORITY_MAX == 8
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highest_ready_priority = rt_lowest_bitmap[rt_thread_ready_priority_group];
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#else
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register rt_ubase_t number;
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/* find out the highest priority task */
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if (rt_thread_ready_priority_group & 0xff)
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{
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number = rt_lowest_bitmap[rt_thread_ready_priority_group & 0xff];
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}
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else if (rt_thread_ready_priority_group & 0xff00)
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{
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number = rt_lowest_bitmap[(rt_thread_ready_priority_group >> 8) & 0xff] + 8;
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}
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else if (rt_thread_ready_priority_group & 0xff0000)
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{
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number = rt_lowest_bitmap[(rt_thread_ready_priority_group >> 16) & 0xff] + 16;
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}
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else
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{
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number = rt_lowest_bitmap[(rt_thread_ready_priority_group >> 24) & 0xff] + 24;
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}
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#if RT_THREAD_PRIORITY_MAX > 32
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highest_ready_priority = (number << 3) +
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rt_lowest_bitmap[rt_thread_ready_table[number]];
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#else
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highest_ready_priority = number;
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#endif
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#endif
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/* get switch to thread */
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to_thread = rt_list_entry(rt_thread_priority_table[highest_ready_priority].next,
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struct rt_thread,
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tlist);
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rt_current_thread = to_thread;
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/* switch to new thread */
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rt_hw_context_switch_to((rt_uint32_t)&to_thread->sp);
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/* never come back */
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}
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/**
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* @addtogroup Thread
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*/
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/*@{*/
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/**
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* This function will perform one schedule. It will select one thread
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* with the highest priority level, then switch to it.
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*/
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void rt_schedule(void)
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{
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rt_base_t level;
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struct rt_thread *to_thread;
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struct rt_thread *from_thread;
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/* disable interrupt */
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level = rt_hw_interrupt_disable();
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/* check the scheduler is enabled or not */
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if (rt_scheduler_lock_nest == 0)
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{
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register rt_ubase_t highest_ready_priority;
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#if RT_THREAD_PRIORITY_MAX == 8
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highest_ready_priority = rt_lowest_bitmap[rt_thread_ready_priority_group];
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#else
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register rt_ubase_t number;
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/* find out the highest priority task */
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if (rt_thread_ready_priority_group & 0xff)
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{
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number = rt_lowest_bitmap[rt_thread_ready_priority_group & 0xff];
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}
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else if (rt_thread_ready_priority_group & 0xff00)
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{
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number = rt_lowest_bitmap[(rt_thread_ready_priority_group >> 8) & 0xff] + 8;
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}
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else if (rt_thread_ready_priority_group & 0xff0000)
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{
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number = rt_lowest_bitmap[(rt_thread_ready_priority_group >> 16) & 0xff] + 16;
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}
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else
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{
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number = rt_lowest_bitmap[(rt_thread_ready_priority_group >> 24) & 0xff] + 24;
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}
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#if RT_THREAD_PRIORITY_MAX > 32
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highest_ready_priority = (number << 3) +
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rt_lowest_bitmap[rt_thread_ready_table[number]];
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#else
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highest_ready_priority = number;
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#endif
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#endif
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/* get switch to thread */
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to_thread = rt_list_entry(rt_thread_priority_table[highest_ready_priority].next,
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struct rt_thread,
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tlist);
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/* if the destination thread is not the same as current thread */
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if (to_thread != rt_current_thread)
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{
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rt_current_priority = (rt_uint8_t)highest_ready_priority;
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from_thread = rt_current_thread;
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rt_current_thread = to_thread;
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RT_OBJECT_HOOK_CALL(rt_scheduler_hook, (from_thread, to_thread));
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/* switch to new thread */
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RT_DEBUG_LOG(RT_DEBUG_SCHEDULER,
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("[%d]switch to priority#%d thread:%s\n",
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rt_interrupt_nest,
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highest_ready_priority,
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to_thread->name));
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#ifdef RT_USING_OVERFLOW_CHECK
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_rt_scheduler_stack_check(to_thread);
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#endif
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if (rt_interrupt_nest == 0)
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{
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rt_hw_context_switch((rt_uint32_t)&from_thread->sp,
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(rt_uint32_t)&to_thread->sp);
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}
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else
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{
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RT_DEBUG_LOG(RT_DEBUG_SCHEDULER, ("switch in interrupt\n"));
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rt_hw_context_switch_interrupt((rt_uint32_t)&from_thread->sp,
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(rt_uint32_t)&to_thread->sp);
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}
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}
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}
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/* enable interrupt */
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rt_hw_interrupt_enable(level);
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}
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/*
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* This function will insert a thread to system ready queue. The state of
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* thread will be set as READY and remove from suspend queue.
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*
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* @param thread the thread to be inserted
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* @note Please do not invoke this function in user application.
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*/
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void rt_schedule_insert_thread(struct rt_thread *thread)
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{
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register rt_base_t temp;
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RT_ASSERT(thread != RT_NULL);
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/* disable interrupt */
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temp = rt_hw_interrupt_disable();
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/* change stat */
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thread->stat = RT_THREAD_READY;
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/* insert thread to ready list */
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rt_list_insert_before(&(rt_thread_priority_table[thread->current_priority]),
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&(thread->tlist));
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/* set priority mask */
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#if RT_THREAD_PRIORITY_MAX <= 32
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RT_DEBUG_LOG(RT_DEBUG_SCHEDULER, ("insert thread[%s], the priority: %d\n",
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thread->name, thread->current_priority));
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#else
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RT_DEBUG_LOG(RT_DEBUG_SCHEDULER,
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("insert thread[%s], the priority: %d 0x%x %d\n",
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thread->name,
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thread->number,
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thread->number_mask,
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thread->high_mask));
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#endif
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#if RT_THREAD_PRIORITY_MAX > 32
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rt_thread_ready_table[thread->number] |= thread->high_mask;
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#endif
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rt_thread_ready_priority_group |= thread->number_mask;
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/* enable interrupt */
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rt_hw_interrupt_enable(temp);
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}
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/*
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* This function will remove a thread from system ready queue.
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*
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* @param thread the thread to be removed
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*
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* @note Please do not invoke this function in user application.
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*/
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void rt_schedule_remove_thread(struct rt_thread *thread)
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{
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register rt_base_t temp;
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RT_ASSERT(thread != RT_NULL);
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/* disable interrupt */
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temp = rt_hw_interrupt_disable();
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#if RT_THREAD_PRIORITY_MAX <= 32
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RT_DEBUG_LOG(RT_DEBUG_SCHEDULER, ("remove thread[%s], the priority: %d\n",
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thread->name, thread->current_priority));
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#else
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RT_DEBUG_LOG(RT_DEBUG_SCHEDULER,
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("remove thread[%s], the priority: %d 0x%x %d\n",
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thread->name,
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thread->number,
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thread->number_mask,
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thread->high_mask));
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#endif
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/* remove thread from ready list */
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rt_list_remove(&(thread->tlist));
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if (rt_list_isempty(&(rt_thread_priority_table[thread->current_priority])))
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{
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#if RT_THREAD_PRIORITY_MAX > 32
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rt_thread_ready_table[thread->number] &= ~thread->high_mask;
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if (rt_thread_ready_table[thread->number] == 0)
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{
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rt_thread_ready_priority_group &= ~thread->number_mask;
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}
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#else
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rt_thread_ready_priority_group &= ~thread->number_mask;
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#endif
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}
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/* enable interrupt */
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rt_hw_interrupt_enable(temp);
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}
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/**
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* This function will lock the thread scheduler.
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*/
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void rt_enter_critical(void)
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{
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register rt_base_t level;
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/* disable interrupt */
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level = rt_hw_interrupt_disable();
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/*
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* the maximal number of nest is RT_UINT16_MAX, which is big
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* enough and does not check here
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*/
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rt_scheduler_lock_nest ++;
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/* enable interrupt */
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rt_hw_interrupt_enable(level);
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}
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/**
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* This function will unlock the thread scheduler.
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*/
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void rt_exit_critical(void)
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{
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register rt_base_t level;
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/* disable interrupt */
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level = rt_hw_interrupt_disable();
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rt_scheduler_lock_nest --;
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if (rt_scheduler_lock_nest <= 0)
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{
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rt_scheduler_lock_nest = 0;
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/* enable interrupt */
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rt_hw_interrupt_enable(level);
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rt_schedule();
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}
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else
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{
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/* enable interrupt */
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rt_hw_interrupt_enable(level);
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}
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}
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/*@}*/
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