179 lines
3.2 KiB
C
179 lines
3.2 KiB
C
/******************************************************************************
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*
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* Copyright (c) 2017-2020 by Löwenware Ltd
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* Please, refer LICENSE file for legal information
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*
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******************************************************************************/
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/**
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* @file task.c
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* @author Ilja Kartašov <ik@lowenware.com>
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* @brief
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*
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* @see https://lowenware.com/
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*/
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#include <stdlib.h>
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#include <aarch64/aarch64.h>
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#include <drivers/soc/bcm2837/bcm2837.h>
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#include "memory.h"
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#include "task.h"
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#define TASK_STATE_RUNNING 0
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#ifndef CONFIG_IDLE_TASK_STACK_SIZE
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#define CONFIG_IDLE_TASK_STACK_SIZE 0x4000
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#endif
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struct Task {
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void *sp;
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void *stackStart;
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uint32_t stackSize;
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uint32_t lock;
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uint32_t counter;
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uint32_t cycles;
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int32_t priority;
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uint32_t state;
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char name[CONFIG_TASK_MAX_NAME_LEN + 1];
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struct Task *next;
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};
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static struct Task *m_currentTask = NULL
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, *m_lastTask = NULL
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, m_idleTask = {
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.sp = NULL
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, .stackStart = NULL
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, .stackSize = CONFIG_IDLE_TASK_STACK_SIZE
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, .lock = 1
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, .counter = 1
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, .cycles = 1
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, .priority = 0
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, .state = TASK_STATE_RUNNING
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, .name = {'I', 'D', 'L', 'E', 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
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, .next = NULL
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};
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static struct Task *
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scheduleNext(void)
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{
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struct Task *i, *next = NULL;
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int32_t priority = -1;
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for (;;) {
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/* check urgent tasks */
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for (i = &m_idleTask; i != NULL; i = i->next) {
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if (i->state != TASK_STATE_RUNNING)
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continue;
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if (i->priority > priority && i->counter) {
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priority = i->priority;
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next = i;
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}
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if (!i->state && i->counter > priority) {
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priority = i->priority;
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next = i;
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}
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}
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if (next) {
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break;
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}
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for (i = &m_idleTask; i != NULL; i = i->next) {
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i->counter = i->cycles;
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}
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}
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return next;
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}
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void
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Task_initSheduler(void)
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{
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struct Task *idleTask = &m_idleTask;
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m_currentTask = idleTask;
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m_lastTask = m_currentTask;
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}
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PID
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Task_create(TaskCallback callback, void *arg)
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{
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struct Task *task = Memory_getPage();
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task->sp = (void *)task + MEMORY_PAGE_SIZE - 272;
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task->stackStart = task->sp;
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task->stackSize = MEMORY_PAGE_SIZE - sizeof(*task);
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task->lock = 1;
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task->counter = 1;
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task->cycles = 1;
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task->priority = 0;
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task->state = TASK_STATE_RUNNING;
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task->name[0] = 'N';
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task->name[1] = 'O';
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task->name[2] = 'N';
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task->name[3] = 'E';
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task->name[4] = 0;
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task->next = 0;
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Task_lockScheduler();
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m_lastTask->next = task;
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m_lastTask = task;
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Task_unlockScheduler();
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return 0;
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}
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void
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Task_yield(void)
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{
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struct Task *next;
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Task_lockScheduler();
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m_currentTask->counter = 0;
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next = scheduleNext();
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if (next != m_currentTask) {
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AArch64_switchContext(m_currentTask, next);
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m_currentTask = next;
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} else {
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__asm__("WFE");
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}
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Task_unlockScheduler();
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}
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void
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Task_lockScheduler(void)
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{
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m_currentTask->lock++;
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}
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void
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Task_unlockScheduler(void)
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{
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m_currentTask->lock--;
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}
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void *
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Task_scheduleFromISR(void)
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{
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void *sp = NULL;
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if (!m_currentTask->lock) {
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struct Task *next;
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Task_lockScheduler();
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next = scheduleNext();
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if (next != m_currentTask) {
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m_currentTask = next;
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sp = next->sp;
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}
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/* unlock call could be moved to aarch64.S interrupt handler in case of
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* issue
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* */
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Task_unlockScheduler();
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}
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return sp;
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}
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