scheduler.c

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#include "icarus/scheduler.h"
#include "icarus/kernel.h"
#include "bsp/config.h"
 
#include <stddef.h>
#ifndef HOST_TEST
#include "stm32h7xx.h"
#else
#include "cmsis_gcc.h"
#endif
 
/* ============================================================================
 * SECTION PLACEMENT MACROS
 * ========================================================================= */
 
/* Defined centrally in icarus/config.h — included via icarus/kernel.h */
 
/* ============================================================================
 * TASK INFORMATION
 * ========================================================================= */
 
/* Task name buffer in RAM_D1 for unprivileged access (DTCM protection) */
#ifndef HOST_TEST
static char task_name_buffer[ICARUS_MAX_TASK_NAME_LEN] __attribute__((section(".ram_d1")));
#else
static char task_name_buffer[ICARUS_MAX_TASK_NAME_LEN];
#endif
 
ITCM_FUNC uint32_t __os_get_tick_count(void) {
    return os_tick_count;
}
 
ITCM_FUNC uint8_t __os_get_running_task_count(void) {
    return running_task_count;
}
 
ITCM_FUNC const char *__os_get_current_task_name(void) {
    if ((current_task_index < num_created_tasks) &&
        (task_list[current_task_index] != NULL)) {
        /* Copy name from DTCM to RAM_D1 buffer so unprivileged code can read it */
        const char *src = task_list[current_task_index]->name;
        char *dst = task_name_buffer;
        const uint8_t name_max = (uint8_t)ICARUS_MAX_TASK_NAME_LEN - 1u;
        uint8_t i = 0u;
        while ((i < name_max) && (src[i] != '\0')) {
            dst[i] = src[i];
            i++;
        }
        dst[i] = '\0';
        return task_name_buffer;
    }
    return "unknown";
}
 
ITCM_FUNC uint32_t __os_get_task_ticks_remaining(void) {
    return current_task_ticks_remaining;
}
 
/* ============================================================================
 * TASK SCHEDULING
 * ========================================================================= */
 
ITCM_FUNC void __os_yield(void) {
    current_task_ticks_remaining = ticks_per_task;
    SCB->ICSR |= SCB_ICSR_PENDSVSET_Msk;
}
 
ITCM_FUNC uint32_t __task_active_sleep(uint32_t ticks) {
    task_list[current_task_index]->global_tick_paused = os_tick_count;
    task_list[current_task_index]->ticks_to_pause = ticks;
    task_list[current_task_index]->task_state = TASK_STATE_BLOCKED;
    __os_yield();
    return os_tick_count - task_list[current_task_index]->global_tick_paused;
}
 
ITCM_FUNC uint32_t __task_blocking_sleep(uint32_t ticks) {
    enter_critical();
    uint32_t delta = task_busy_wait(ticks);
    exit_critical();
    return delta;
}
 
ITCM_FUNC uint32_t __task_busy_wait(uint32_t ticks) {
    uint32_t st = os_get_tick_count();
    uint32_t delta;
 
    while (1) {
#ifdef HOST_TEST
        os_tick_count++;
#endif
        delta = os_get_tick_count() - st;
        if (delta >= ticks) {
            break;
        }
    }
    return delta;
}