add some comments and clean code in cpu_port.c
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prife
parent
212b71205b
commit
5685a395be
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@ -1,3 +1,8 @@
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/*
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* author : prife (goprife@gmail.com)
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* date : 2013/01/14 01:18:50
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* version: v 0.1.0
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*/
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#include <rtthread.h>
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#include <stdio.h>
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#include <stdlib.h>
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@ -10,7 +15,6 @@
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//#define TRACE printf
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#define TRACE(...)
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#define _DEBUG
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typedef struct _thread
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{
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@ -31,10 +35,11 @@ typedef struct _thread
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#define TIMER_TYPE ITIMER_REAL
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#define MAX_INTERRUPT_NUM ((unsigned int)sizeof(unsigned int) * 8)
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#define INTERRUPT_ENABLE 0
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#define INTERRUPT_DISABLE 1
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/* interrupt flag, if 1, disable, if 0, enable */
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static long interrupt_disable_flag;
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/* #define INT_ENABLE 0
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* #define INT_DISABLE 1
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*/
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/* flag in interrupt handling */
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rt_uint32_t rt_interrupt_from_thread, rt_interrupt_to_thread;
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rt_uint32_t rt_thread_switch_interrupt_flag;
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@ -181,29 +186,28 @@ rt_uint8_t *rt_hw_stack_init(
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return (rt_uint8_t *) thread;
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}
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static int dis_count;
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static int en_count;
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/* interrupt contex switch hit, value 1 or 0 */
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static long int_cs_hit;
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/* TODO: 此函数还没有真正实现 */
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rt_base_t rt_hw_interrupt_disable(void)
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{
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if (ptr_int_mutex != NULL)
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{
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// pthread_mutex_lock(ptr_int_mutex); //FIXME
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}
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/*TODO: It may need to mask the signal */
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return 0;
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long back;
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back = interrupt_disable_flag;
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interrupt_disable_flag = INTERRUPT_DISABLE;
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/*TODO: It may need to unmask the signal */
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dis_count++;
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return back;
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}
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/* TODO: 此函数还没有真正实现 */
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void rt_hw_interrupt_enable(rt_base_t level)
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{
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level = level;
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interrupt_disable_flag = level;
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if (ptr_int_mutex != NULL)
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{
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// pthread_mutex_unlock(ptr_int_mutex); //FIXME
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}
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en_count++;
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/*TODO: It may need to unmask the signal */
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}
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@ -224,6 +228,7 @@ void rt_hw_context_switch(rt_uint32_t from,
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RT_ASSERT(from != to);
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#if 0
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//TODO: 还需要考虑嵌套切换的情况
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if (rt_thread_switch_interrupt_flag != 1)
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{
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rt_thread_switch_interrupt_flag = 1;
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@ -242,19 +247,32 @@ void rt_hw_context_switch(rt_uint32_t from,
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tid = rt_thread_self();
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pid = pthread_self();
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/* 注意，只有两种可可能，一种是线程函数中调用此函数，一种是在中断中调用
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* 而在中断调用是在主线程的信号处理函数中实现（目前只有tick中断）。
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* 即, 只有如下两种可能:
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* 1)普通RTT线程间接调用，如rt_thread_delay函数
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* 2)或者主线程信号处理函数,如rt_tick_increase中调用
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/*
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* FIXME: 这段代码应该删除，因为rt_schedule函数中是先关闭中断，然后再开启的
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* 开启就会出发PendSV（以stm32为例）中断，cpu_port.c的win32版本可以模拟这种
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* 情形，因为它的中断是在主线程代码实现的，而本设计中，切换分为两种情况，
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* 1) 普通rtt线程调用rt_thread_delay/rt_sem_take等主动挂起时，即刻实现切换
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* 2) 当rt_thread_delay定时到期时，主线程的SIGALRM信号处理函数中实现线程切换
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*
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* 在第一种情况下，如果添加打开如下代码，由于if中语句为真，会导致失败退出。
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*
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if (interrupt_disable_flag != 0)
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{
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printf("dis_count=%d, en_count=%d\n", dis_count, en_count);
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printf("interrupt_disable_flag = %d\n", interrupt_disable_flag);
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printf("bug! interrupt is disabled! You may forget enable interrupt\n");
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exit(EXIT_FAILURE);
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}
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*/
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if (pid != mainthread_pid)
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{
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/* FIXME: 注意这段代码是在RTT普通线程函数总函数中执行的，
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* from线程就是当前rtt线程 */
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TRACE("conswitch: P in pid<%x> ,suspend <%s>, resume <%s>!\n",
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(unsigned int)pid,
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thread_from->rtthread->name,
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thread_to->rtthread->name);
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/* from线程就是当前rtt线程 */
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/* 确定一下，这两个值一定是相等的！ */
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RT_ASSERT(thread_from->pthread == pid);
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@ -263,14 +281,14 @@ void rt_hw_context_switch(rt_uint32_t from,
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sem_post(& thread_to->sem);
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/* 挂起from线程, 既然from线程就是当前线程，所以应该直接
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* 挂起在这里
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*/
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* 挂起在这里 */
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sem_wait(& thread_from->sem);
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}
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else
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{
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/* FIXME: 注意这段代码是在system tick 函数中执行的，
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* 即此时位于主线程的SIGALRM信号处理函数中 */
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* 即此时位于主线程的SIGALRM信号处理函数中
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*/
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TRACE("conswitch: S in pid<%x> ,suspend <%s>, resume <%s>!\n",
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(unsigned int)pid,
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thread_from->rtthread->name,
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@ -293,7 +311,11 @@ void rt_hw_context_switch_to(rt_uint32_t to)
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rt_interrupt_from_thread = 0;
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//set interrupt to 1
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rt_thread_switch_interrupt_flag = 0; //<------
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rt_thread_switch_interrupt_flag = 0; //TODO: 还需要考虑这个嵌套切换的情况
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/* enable interrupt
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* note: NOW, there are only one interrupt in simposix: system tick */
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rt_hw_interrupt_enable(0);
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//start the main thread scheduler
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mainthread_scheduler();
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@ -315,21 +337,19 @@ static int mainthread_scheduler(void)
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mainthread_pid = pthread_self();
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TRACE("pid <%08x> mainthread\n", (unsigned int)(mainthread_pid));
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/* register interrupts which is simulated for yield and systick */
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//register_interrupt(CPU_INTERRUPT_YIELD, yield_interrupt_isr);
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//register_interrupt(CPU_INTERRUPT_TICK, tick_interrupt_isr);
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/* install signal handler of system tick */
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signal_install(SIGALRM, mthread_signal_tick);
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/* install signal handler used to suspend itself */
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signal_install(MSG_SUSPEND, thread_switch_handler);
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#if 0
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/* create a mutex and condition val, used to indicate interrupts occrue */
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ptr_int_mutex = &mutex;
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pthread_mutexattr_init(&mutexattr);
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pthread_mutexattr_settype(&mutexattr, PTHREAD_MUTEX_RECURSIVE);
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pthread_mutex_init(ptr_int_mutex, &mutexattr);
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pthread_cond_init(&cond_int_hit, NULL);
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#endif
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/* start timer */
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start_sys_timer();
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@ -341,18 +361,6 @@ static int mainthread_scheduler(void)
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for (;;)
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{
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#if 0
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pthread_mutex_lock(ptr_int_mutex);
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/*Lock mutex and wait for signal. Note that the pthread_cond_wait
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*routine will automatically and atomically unlock mutex while it waits.
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*/
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TRACE("mthread: wait cond val!\n");
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pthread_cond_wait(&cond_int_hit, ptr_int_mutex);
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TRACE("mthread: got cond val!\n");
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pthread_mutex_unlock(ptr_int_mutex);
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#endif
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//printf("main thread...\n");
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sleep(1);
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}
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@ -402,7 +410,13 @@ static void mthread_signal_tick(int sig)
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if (sig == SIGALRM)
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{
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TRACE("pid <%x> signal: SIGALRM enter!\n", (unsigned int)pid);
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/* FIXME: 下面这条语句不能打开，打开就会导致失败tick_interrupt_isry
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* 永远无法执行
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*/
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/* if (! interrupt_disable_flag) */
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tick_interrupt_isr();
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TRACE("pid <%x> signal: SIGALRM leave!\n", (unsigned int)pid);
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}
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else
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@ -428,20 +442,3 @@ static int tick_interrupt_isr(void)
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return 0;
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}
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#if 0
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static void trigger_interrupt(int index)
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{
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if ((index < MAX_INTERRUPT_NUM) && ptr_int_mutex != NULL)
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{
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pthread_mutex_lock(ptr_int_mutex);
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cpu_pending_interrupts |= (1 << index);
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/* signal the condition val */
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pthread_cond_signal(&cond_int_hit);
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pthread_mutex_unlock(ptr_int_mutex);
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}
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}
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#endif
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