ardupilot/libraries/AP_HAL_F4Light/Scheduler.cpp

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/*
(c) 2017 night_ghost@ykoctpa.ru
*/
#pragma GCC optimize ("O2")
#include "Scheduler.h"
#include <stdio.h>
#include <AP_HAL_F4Light/AP_HAL_F4Light.h>
#include "Semaphores.h"
#include "I2CDevice.h"
#include <timer.h>
#include <AP_Notify/AP_Notify.h>
#include <AP_Math/AP_Math.h>
#include <AP_Param_Helper/AP_Param_Helper.h>
#include "RCInput.h"
#include <systick.h>
#include "GPIO.h"
#include <usb.h>
using namespace F4Light;
extern const AP_HAL::HAL& hal;
AP_HAL::Proc Scheduler::_failsafe IN_CCM= NULL;
Revo_IO Scheduler::_io_proc[F4Light_SCHEDULER_MAX_IO_PROCS] IN_CCM;
uint8_t Scheduler::_num_io_proc IN_CCM=0;
void * Scheduler::_delay_cb_handle IN_CCM=0;
uint32_t Scheduler::timer5_ovf_cnt IN_CCM=0;
bool Scheduler::_initialized IN_CCM=false;
Handler Scheduler::on_disarm_handler IN_CCM;
task_t * Scheduler::_idle_task IN_CCM;
void *Scheduler::boost_task;
static void loc_ret(){}
#define STACK_GUARD 0x60a4d51aL
// Reference running task
task_t* s_running IN_CCM;
task_t* next_task IN_CCM;
// Main task and run queue
task_t Scheduler::s_main = { 0 }; // NOT in CCM to can't be corrupted by stack
uint16_t Scheduler::task_n=0;
struct Scheduler::IO_COMPLETION Scheduler::io_completion[MAX_IO_COMPLETION] IN_CCM;
uint8_t Scheduler::num_io_completion IN_CCM= 0;
// Initial top stack for task allocation
size_t Scheduler::s_top IN_CCM; // = MAIN_STACK_SIZE; - CCM not initialized!
#ifdef SHED_PROF
uint64_t Scheduler::shed_time = 0;
bool Scheduler::flag_10s = false;
uint64_t Scheduler::task_time IN_CCM = 0;
uint64_t Scheduler::delay_time IN_CCM = 0;
uint64_t Scheduler::delay_int_time IN_CCM = 0;
uint32_t Scheduler::max_loop_time IN_CCM =0;
uint64_t Scheduler::ioc_time IN_CCM =0;
uint64_t Scheduler::sleep_time IN_CCM =0;
uint32_t Scheduler::max_delay_err=0;
uint32_t Scheduler::tick_micros IN_CCM; // max exec time
uint32_t Scheduler::tick_count IN_CCM; // number of calls
uint64_t Scheduler::tick_fulltime IN_CCM; // full consumed time to calc mean
#endif
#ifdef MTASK_PROF
uint32_t Scheduler::max_wfe_time IN_CCM =0;
uint32_t Scheduler::tsched_count IN_CCM;
uint32_t Scheduler::tsched_sw_count IN_CCM;
uint32_t Scheduler::tsched_count_y IN_CCM;
uint32_t Scheduler::tsched_sw_count_y IN_CCM;
uint32_t Scheduler::tsched_count_t IN_CCM;
uint32_t Scheduler::tsched_sw_count_t IN_CCM;
#ifdef SHED_DEBUG
revo_sched_log Scheduler::logbuf[SHED_DEBUG_SIZE] IN_CCM;
uint16_t Scheduler::sched_log_ptr;
#endif
uint32_t Scheduler::lowest_stack = (uint32_t)-1;
#endif
bool Scheduler::_in_io_proc IN_CCM =0;
#ifdef MPU_DEBUG
uint32_t Scheduler::MPU_overflow_cnt IN_CCM;
uint32_t Scheduler::MPU_restart_cnt IN_CCM;
uint32_t Scheduler::MPU_count IN_CCM;
uint32_t Scheduler::MPU_Time IN_CCM;
#endif
volatile bool Scheduler::need_switch_task IN_CCM;
task_t *Scheduler::_forced_task IN_CCM;
Scheduler::Scheduler()
{
s_running = &s_main; // CCM don't initialized! - Reference running task
next_task = &s_main;
s_top = MAIN_STACK_SIZE; // Initial top stack for task allocation
// init main task
memset(&s_main, 0, sizeof(s_main));
Revo_handler h = { .vp=loc_ret }; // fake handler to not 0
s_main.next = &s_main; // linked list
s_main.prev = &s_main;
s_main.priority = MAIN_PRIORITY; // base priority
s_main.active = true; // not paused
s_main.handle = h.h; // to not 0
s_main.guard = STACK_GUARD; // to check corruption of TCB by stack overflow
#ifdef MTASK_PROF
s_main.stack_free = (uint32_t) -1;
#endif
_forced_task = NULL;
}
// to do when nothing to do
static void idle_task(){
while(1){
__WFE();
// see RM090 12.2.3
TIMER6->regs->SR &= TIMER_SR_UIF; // reset pending bit
NVIC_ClearPendingIRQ(TIM6_DAC_IRQn); // timer6 as event generator - reset IRQ
Scheduler::yield(0);
}
}
void Scheduler::init()
{
if(in_interrupt()){ // some interrupt caused restart at ISR level
AP_HAL::panic("HAL initialization on ISR level=0x%x", (uint8_t)(SCB->ICSR & SCB_ICSR_VECTACTIVE_Msk));
}
memset(_io_proc, 0, sizeof(_io_proc) );
memset(io_completion, 0, sizeof(io_completion) );
// The PendSV exception is always enabled so disable interrupts
// to prevent it from occurring while being configured
noInterrupts();
NVIC_SetPriority(PendSV_IRQn, PENDSV_INT_PRIORITY); // lowest priority so all IRQs can't be switced
NVIC_SetPriority(SVCall_IRQn, SVC_INT_PRIORITY); // priority 14 - the same as Timer7 ISR
NVIC_SetPriority(SysTick_IRQn, SYSTICK_INT_PRIORITY); // priority 5 - less thah fast device IO ISRs but higher than USB
// Ensure the effect of the priority change occurs before
// clearing PRIMASK to ensure that future PendSV exceptions
// are taken at the new priority
asm volatile("dsb \n");
asm volatile("isb \n");
interrupts();
CLEAR_BIT(SCB->SCR, ((uint32_t)SCB_SCR_SLEEPDEEP_Msk)); //we don't need deep sleep
SET_BIT( SCB->SCR, ((uint32_t)SCB_SCR_SEVONPEND_Msk)); //we need Event on each interrupt
/*[ DEBUG
SCnSCB->ACTLR |= SCnSCB_ACTLR_DISDEFWBUF_Msk; // disable imprecise exceptions
//]*/
timer_foreach(timer_reset); // timer_reset(dev) moved out from configTimeBase so reset by hands
{// timeslice timer, not SYSTICK because we need to restart it by hands
uint32_t period = (2000000UL / SHED_FREQ) - 1;
// dev period freq, kHz
configTimeBase(TIMER7, period, 2000); //2MHz 0.5us ticks
Revo_handler h = { .isr = _timer_isr_event };
timer_attach_interrupt(TIMER7, TIMER_UPDATE_INTERRUPT, h.h , SVC_INT_PRIORITY); // almost lowest priority, higher than Pend_SW to schedule task switch
TIMER7->regs->CR1 |= TIMER_CR1_URS; // interrupt only by overflow, not by update
timer_resume(TIMER7);
}
{// timer5 - 32-bit general timer, unused for other needs
// so we can read micros32() directly from its counter and micros64() from counter and overflows
configTimeBase(TIMER5, 0, 1000); //1MHz 1us ticks
timer_set_count(TIMER5,(1000000/SHED_FREQ)/2); // to not interfere with TIMER7
Revo_handler h = { .isr = _timer5_ovf };
timer_attach_interrupt(TIMER5, TIMER_UPDATE_INTERRUPT, h.h, MPU_INT_PRIORITY); // high priority
timer_resume(TIMER5);
}
{ // only Timer6 from spare timers has personal NVIC line - TIM6_DAC_IRQn
uint32_t freq = configTimeBase(TIMER6, 0, 20000); // 20MHz - we here don't know real freq so can't set period
timer_set_reload(TIMER6, freq / 1000000); // period to generate 1uS requests
timer_enable_irq(TIMER6, TIMER_UPDATE_INTERRUPT); // enable interrupt requests from timer but not enable them in NVIC - will be events
timer_resume(TIMER6);
}
{ // timer to generate more precise delays via quant termination
// dev period freq, kHz
configTimeBase(TIMER14, 0, 1000); //1MHz 1us ticks
Revo_handler h = { .isr = _tail_timer_event };
timer_attach_interrupt(TIMER14, TIMER_UPDATE_INTERRUPT, h.h , SVC_INT_PRIORITY); // priority 14 - the same as Timer7 and SVC
TIMER14->regs->CR1 &= ~(TIMER_CR1_ARPE | TIMER_CR1_URS); // not buffered preload, interrupt by overflow or by UG set
}
{ // timer to generate interrupt for driver's IO_Completion
// dev period freq, kHz
configTimeBase(TIMER13, 0, 1000); //1MHz 1us ticks
Revo_handler h = { .isr = _ioc_timer_event };
timer_attach_interrupt(TIMER13, TIMER_UPDATE_INTERRUPT, h.h , IOC_INT_PRIORITY); // priority 12
TIMER13->regs->CR1 &= ~(TIMER_CR1_ARPE | TIMER_CR1_URS); // not buffered preload, interrupt by overflow or by UG set
}
void *task = _start_task((uint32_t)idle_task, 256); // only for one context
set_task_priority(task, 255); // lowest possible, to fill delay()
_idle_task=(task_t *)task;
set_task_active(task); // tasks are created paused so run it
}
// it can't be started on init() because should be stopped in later_init()
void Scheduler::start_stats_task(){
#ifdef DEBUG_BUILD
// show stats output each 10 seconds
Revo_handler h = { .vp = _set_10s_flag };
void *task = _register_timer_task(10000000, h.h, NULL);
set_task_priority(task, IO_PRIORITY+1); // lower than IO_thread
#endif
// task list is filled. so now we can do a trick -
// dequeue_task(_idle_task); // exclude idle task from task queue, it will be used by direct link.
// its own .next still shows to next task so no problems will. This works but...
}
void Scheduler::_delay(uint16_t ms)
{
uint32_t start = _micros();
#ifdef SHED_PROF
uint32_t t=start;
#endif
uint32_t dt = ms * 1000;
uint32_t now;
while((now=_micros()) - start < dt) {
if (hal.scheduler->_min_delay_cb_ms <= ms) { // MAVlink callback uses 5ms
hal.scheduler->call_delay_cb();
yield(1000 - (_micros() - now)); // to not stop MAVlink callback
} else {
yield(dt); // for full time
}
}
#ifdef SHED_PROF
uint32_t us=_micros()-t;
delay_time +=us;
#endif
}
// also see resume_boost()
// this used from InertialSensor only
void Scheduler::_delay_microseconds_boost(uint16_t us){
boost_task=get_current_task();
#ifdef SHED_PROF
uint32_t t = _micros();
#endif
yield(us); // yield raises priority by 6 so task will be high-priority for 1st time
#ifdef SHED_PROF
uint32_t r_us=_micros()-t; // real time
delay_time +=r_us;
#endif
boost_task=NULL;
}
#define NO_YIELD_TIME 8 // uS
void Scheduler::_delay_microseconds(uint16_t us)
{
#ifdef SHED_PROF
uint32_t t = _micros();
#endif
uint16_t no_yield_t; // guard time for main process
no_yield_t=NO_YIELD_TIME;
if(us > no_yield_t){
yield(us);
#ifdef SHED_PROF
uint32_t r_us=_micros()-t; // real time
delay_time +=r_us;
#endif
}else{
_delay_us_ny(us);
}
}
void Scheduler::_delay_us_ny(uint16_t us){ // precise no yield delay
uint32_t rtime = stopwatch_getticks(); // get start ticks first
uint32_t dt = us_ticks * us; // delay time in ticks
while ((stopwatch_getticks() - rtime) < dt) {
// __WFE(); -- not helps very much
}
#ifdef SHED_PROF
delay_time +=us;
#endif
}
void Scheduler::register_delay_callback(AP_HAL::Proc proc, uint16_t min_time_ms)
{
static bool init_done=false;
if(!init_done){ // small hack to load HAL parameters in needed time
((HAL_F4Light&) hal).lateInit();
init_done=true;
}
AP_HAL::Scheduler::register_delay_callback(proc, min_time_ms);
/*
1 - it should run in delay() only
2 - it should be removed after init done
if(proc) {
_delay_cb_handle = start_task(proc);
} else {
stop_task(_delay_cb_handle);
}
*/
}
void Scheduler::_run_io(void)
{
if (_in_io_proc) {
return;
}
_in_io_proc = true;
// now call the IO based drivers. TODO: per-task stats
for (int i = 0; i < _num_io_proc; i++) {
if (_io_proc[i].h) {
revo_call_handler(_io_proc[i].h,0);
if(_io_proc[i].flags == IO_ONCE){
_io_proc[i].h = 0;
}
}
}
_in_io_proc = false;
}
void Scheduler::_register_io_process(Handler h, Revo_IO_Flags flags)
{
if(_num_io_proc>=F4Light_SCHEDULER_MAX_IO_PROCS) return;
if(_num_io_proc==0){
void *task = start_task(_run_io, IO_STACK_SIZE);
set_task_period(task, 1000);
set_task_priority(task, IO_PRIORITY);
}
uint8_t i;
for(i=0; i<_num_io_proc; i++){ // find free slots
if(_io_proc[i].h == 0) { // found
_io_proc[i].h = h;
_io_proc[i].flags = flags;
return;
}
}
i=_num_io_proc++;
_io_proc[i].h = h;
_io_proc[i].flags = flags;
}
#ifdef MTASK_PROF
void Scheduler::check_stack(uint32_t sp) { // check for stack usage
// uint32_t * stack = (uint32_t *)sp;
// Stack frame contains:
// r0, r1, r2, r3, r12, r14, the return address and xPSR
// - Stacked R0 = stack[0]
// - Stacked R1 = stack[1]
// - Stacked R2 = stack[2]
// - Stacked R3 = stack[3]
// - Stacked R12 = stack[4]
// - Stacked LR = stack[5]
// - Stacked PC = stack[6]
// - Stacked xPSR= stack[7]
if(ADDRESS_IN_CCM(sp)){
if(sp<lowest_stack){ lowest_stack=sp; }
}
}
#endif
void Scheduler::_run_timer_procs(bool called_from_isr) {
// and the failsafe, if one is setted
if (_failsafe) {
static uint32_t last_failsafe=0;
uint32_t t=_millis();
if(t-last_failsafe>10){
last_failsafe = t+50; // 50ms = 20Hz
_failsafe();
}
}
}
void Scheduler::_timer_isr_event(uint32_t v /* TIM_TypeDef *tim */) {
#ifdef MTASK_PROF
uint32_t sp;
// Get stack pointer
asm volatile ("MRS %0, PSP\n\t" : "=rm" (sp));
check_stack(sp);
#endif
static uint32_t last_timer_procs=0;
uint32_t now = _micros();
if(now - last_timer_procs >= 1000) {
last_timer_procs = now;
_run_timer_procs(true);
}
#ifndef MTASK_PROF
_switch_task();
#else
if(task_n==0 || need_switch_task) return; // if there no tasks or already planned
next_task = get_next_task();
tsched_count++;
if(next_task != s_running) { // if we should switch task
s_running->sw_type=0;
tsched_sw_count++;
plan_context_switch(); // plan context switch after return from ISR
}
#endif
}
void Scheduler::_timer5_ovf(uint32_t v /* TIM_TypeDef *tim */) {
timer5_ovf_cnt++;
}
uint64_t Scheduler::_micros64() {
#pragma pack(push, 1)
union {
uint64_t t;
uint32_t w[2];
} now;
#pragma pack(pop)
noInterrupts();
now.w[0] = _micros();
now.w[1] = timer5_ovf_cnt;
interrupts();
return now.t;
}
void Scheduler::system_initialized()
{
#ifndef I_KNOW_WHAT_I_DO
if (_initialized) {
AP_HAL::panic("PANIC: scheduler::system_initialized called more than once");
}
#endif
_initialized = true;
board_set_rtc_register(0,RTC_SIGNATURE_REG); // clear bootloader flag after init done
}
void Scheduler::_reboot(bool hold_in_bootloader) {
if(hold_in_bootloader) {
#if 1
if(is_bare_metal() || hal_param_helper->_boot_dfu) { // bare metal build without bootloader of parameter set
board_set_rtc_register(DFU_RTC_SIGNATURE, RTC_SIGNATURE_REG);
} else
#endif
board_set_rtc_register(BOOT_RTC_SIGNATURE, RTC_SIGNATURE_REG);
}
_delay(100);
NVIC_SystemReset();
_delay(1000);
}
void Scheduler::reboot(bool hold_in_bootloader) {
hal.console->println("GOING DOWN FOR A REBOOT\r\n");
_reboot(hold_in_bootloader);
}
#ifdef DEBUG_BUILD
extern "C" {
extern void *__brkval;
extern void *__brkval_ccm;
}
void Scheduler::_print_stats(){
static int cnt=0;
if(flag_10s) {
flag_10s=false;
#if defined(USE_MPU)
mpu_disable(); // we need access to all tasks
#endif
uint32_t t=_millis();
const int Kf=100;
switch(cnt++) {
case 0:{
#ifdef SHED_PROF
float eff= (task_time)/(float)(task_time+shed_time);
static float shed_eff=0;
if(is_zero(shed_eff)) shed_eff = eff;
else shed_eff = shed_eff*(1 - 1/Kf) + eff*(1/Kf);
printf("\nSched stats: uptime %lds\n %% of full time: %5.2f Efficiency %5.3f max loop time %ld\n", t/1000, (task_time/10.0)/t /* in percent*/ , shed_eff, max_loop_time);
printf("delay times: in main %5.2f including in timer %5.2f", (delay_time/10.0)/t, (delay_int_time/10.0)/t);
max_loop_time=0;
#ifdef ISR_PROF
printf("\nISR time %5.2f max %5.2f", (isr_time/10.0/(float)us_ticks)/t, max_isr_time/(float)us_ticks );
max_isr_time=0;
#endif
#ifdef MPU_DEBUG
printf("MPU overflows: %ld restarts %ld max samples %ld time %ld\n", MPU_overflow_cnt, MPU_restart_cnt, MPU_count, MPU_Time); MPU_overflow_cnt=0; MPU_restart_cnt=0; MPU_count=0; MPU_Time=0;
#endif
printf("\nPPM max buffer size: %d\n", RCInput::max_num_pulses); RCInput::max_num_pulses=0;
#endif
} break;
case 1:{
#ifdef SHED_PROF
#endif
}break;
case 2:{
#ifdef MTASK_PROF
task_t* ptr = &s_main;
uint32_t fc=tsched_count+tsched_count_y+tsched_count_t;
printf("\nsched time: by timer %5.2f%% sw %5.2f%% in yield %5.2f%% sw %5.2f%% in tails %5.2f%% sw %5.2f%%\n", 100.0*tsched_count/fc, 100.0 * tsched_sw_count/tsched_count, 100.0*tsched_count_y/fc,100.0 * tsched_sw_count_y/tsched_count_y, 100.0*tsched_count_t/fc, 100.0 * tsched_sw_count_t/tsched_count_t);
do {
printf("task %d (0x%015llx) time: %7.2f%% mean %8.1fuS max %5lduS full %7lduS wait sem. %6lduS free stack 0x%lx\n",
ptr->id, ptr->handle, 100.0 * ptr->time/1000.0 / t,
(float)ptr->time / ptr->count,
ptr->max_time,
ptr->work_time, ptr->sem_max_wait, ptr->stack_free);
ptr->max_time=0; // reset times
ptr->work_time=0;
ptr->sem_max_wait=0;
ptr->quants=0;
ptr->quants_time=0;
ptr->max_paused=0;
ptr = ptr->next;
} while(ptr != &s_main);
#endif
}break;
case 3: {
uint8_t n = I2CDevice::get_dev_count();
printf("\nI2C stats\n");
for(uint8_t i=0; i<n; i++){
I2CDevice * d = I2CDevice::get_device(i);
if(d){
printf("bus %d addr %x errors %ld last error=%d state=%d\n",d->get_bus(), d->get_addr(), d->get_error_count(), d->get_last_error(), d->get_last_error_state());
}
}
}break;
case 4: {
uint32_t heap_ptr = (uint32_t)__brkval; // upper bound of sbrk()
uint32_t bottom = (uint32_t)&_sdata;
// 48K after boot 72K while logging on
printf("\nMemory used: static %ldk full %ldk\n",((uint32_t)&_edata-bottom+1023)/1024, (heap_ptr-bottom+1023)/1024);
printf("Free stack: %ldk\n",(lowest_stack - (uint32_t)&_eccm)/1024);
printf("CCM use: %ldk\n",((uint32_t)__brkval_ccm - (uint32_t)&_sccm)/1024);
} break;
case 5: {
printf("\nIO completion %7.3f%%\n", ioc_time/1000.0/t*100);
uint64_t iot=0;
for(uint8_t i=0; i<num_io_completion; i++){
struct IO_COMPLETION &io = io_completion[i];
if(io.handler) {
if(io.count){
printf("task %llx time %7.3f%% mean %7.3fuS max %lduS\n", io.handler, 100.0 * io.time / t / 1000, (float)io.time/io.count, io.max_time);
io.max_time=0;
iot+=io.time;
}
}
}
if(ioc_time)
printf("IO completion effectiveness=%7.3f%%\n", 100.0 * iot/ioc_time);
}break;
case 6:
default:
cnt=0;
break;
}
}
}
void Scheduler::_set_10s_flag(){
flag_10s=true;
_print_stats();
}
#endif
/*
[ common implementation of all Device.PeriodicCallback;
*/
AP_HAL::Device::PeriodicHandle Scheduler::_register_timer_task(uint32_t period_us, Handler proc, F4Light::Semaphore *sem){
// all drivers will runs at individual IO tasks
void *task = _start_task(proc, SMALL_TASK_STACK);
if(task){
set_task_priority(task, DRIVER_PRIORITY);
set_task_semaphore(task, sem);
set_task_period(task, period_us); // setting of period allows task to run
}
return (AP_HAL::Device::PeriodicHandle)task;
}
bool Scheduler::adjust_timer_task(AP_HAL::Device::PeriodicHandle h, uint32_t period_us)
{
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wcast-align" // yes I know
task_t *p = (task_t *)h;
#pragma GCC diagnostic pop
p->period = period_us;
return true;
}
bool Scheduler::unregister_timer_task(AP_HAL::Device::PeriodicHandle h)
{
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wcast-align"
task_t *p = (task_t *)h;
#pragma GCC diagnostic pop
noInterrupts(); // 64-bits should be
p->handle=0L;
interrupts();
return true;
}
// ]
//[ -------- preemptive multitasking --------
#if 0 // once started tasks are never ended
task_t* Scheduler::get_empty_task(){
task_t* ptr = &s_main;
do {
if(ptr->handler == NULL) return ptr;
ptr = ptr->next;
} while(ptr != &s_main);
return NULL;
}
#endif
void Scheduler::stop_task(void *h){
if(h) {
task_t *tp = (task_t *)h ;
noInterrupts();
tp->handle = 0;
interrupts();
}
}
// task's executor, which calls user's function having semaphore
void Scheduler::do_task(task_t *task) {
while(1){
uint32_t t=0;
if(task->handle && task->active) { // Task Switch occures asyncronously so we should wait until task becomes active again
task->time_start=_micros();
if(task->sem) {// if task requires a semaphore - block on it
if(!task->sem->take(HAL_SEMAPHORE_BLOCK_FOREVER)) {
yield(0); // can't be
continue;
}
revo_call_handler(task->handle, task->id);
task->sem->give(); // give semaphore when task finished
} else {
revo_call_handler(task->handle, task->id);
}
#ifdef MTASK_PROF
t = _micros()-task->time_start; // execution time
if(t > task->work_time) task->work_time=t;
if(task->t_paused > task->max_paused) {
task->max_paused = task->t_paused;
}
if(task->count_paused>task->max_c_paused) {
task->max_c_paused = task->count_paused;
}
task->count_paused=0;
task->t_paused=0;
#endif
task->active=false; // turn off active, to know when task is started again. last! or can never give semaphore
task->curr_prio = task->priority - 6; // just activated task will have a highest priority for one quant
}
yield(0); // give up quant remainder
} // endless loop
}
void Scheduler::enqueue_task(task_t &tp) { // add new task to run queue, starting main task
tp.next = &s_main; // prepare for insert task into linked list
tp.prev = s_main.prev;
tp.id = ++task_n; // counter - new task is created
noInterrupts(); // we will break linked list so do it in critical section
s_main.prev->next = &tp;
s_main.prev = &tp;
interrupts(); // now TCB is ready to task scheduler
}
void Scheduler::dequeue_task(task_t &tp) { // remove task from run queue
noInterrupts(); // we will break linked list so do it in critical section
tp.prev->next = tp.next;
tp.next->prev = tp.prev;
interrupts(); // done
}
// Create task descriptor
uint32_t Scheduler::fill_task(task_t &tp){
memset(&tp,0,sizeof(tp));
// fill required fields
tp.priority = MAIN_PRIORITY; // default priority equal to main task
tp.curr_prio = MAIN_PRIORITY; // current priority the same
#ifdef MTASK_PROF
tp.start=_micros();
tp.stack_free = (uint32_t) -1;
#endif
tp.guard = STACK_GUARD;
return (uint32_t)&tp;
}
// create task descriptor and context
void * Scheduler::init_task(Handler handler, const uint8_t* stack){
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wcast-align" // yes I know
// task_t *task = (task_t *)((uint32_t)(stack-sizeof(task_t)) & 0xFFFFFFFCUL); // control block below memory top, 4-byte alignment
task_t *task = (task_t *)((uint32_t)(stack-sizeof(task_t)) & 0xFFFFFFE0UL); // control block below memory top, 32-byte alignment for MMU page
#pragma GCC diagnostic pop
fill_task(*task); // fill task descriptor
task->stack = stack;
/*
* ARM Architecture Procedure Call Standard [AAPCS] requires 8-byte stack alignment.
* This means that we must get top of stack aligned _after_ context "pushing", at
* interrupt entry.
*/
uint32_t *sp =(uint32_t *) (((uint32_t)task - 4) & 0xFFFFFFF8UL); // below TCB
// HW frame
*(--sp) = 0x01000000UL; // xPSR
// 61000000
*(--sp) = ((uint32_t)do_task); // PC Entry Point - task executor
*(--sp) = ((uint32_t)do_task)|1; // LR the same, with thumb bit set
sp -= 4; // emulate "push R12,R3,R2,R1"
*(--sp) = (uint32_t)task; // emulate "push r0"
// SW frame, context saved as "STMDB R0!, {R4-R11, LR}"
*(--sp) = 0xFFFFFFFDUL; // emulate "push lr" =exc_return: Return to Thread mode, floating-point context inactive, execution uses PSP after return.
#if 0
asm volatile (
"MOV R0, %0 \n\t"
"STMDB R0!, {R4-R11}\n\t" : "+rm" (sp) ); // push real registers - they can be global register variables
"MOV %0,R0 \n\t"
#else
sp -= 8; // emulate "push R4-R11"
#endif
task->sp=(uint8_t *)sp; // set stack pointer of task
// task is not active so we need not to disable interrupts
task->handle = handler; // save handler to TCB
return (void *)task;
}
// create a paused task
void * NOINLINE Scheduler::_start_task(Handler handle, size_t stackSize)
{
// Check called from main task
if (!_in_main_thread() ) return NULL;
if(in_interrupt()) {
AP_HAL::panic("start_task called from ISR 0x%x", (uint8_t)(SCB->ICSR & SCB_ICSR_VECTACTIVE_Msk));
}
#if defined(USE_MPU)
mpu_disable(); // we need access to new tasks TCB which can be overlapped by guard page
#endif
// Adjust stack size with size of task context
stackSize += sizeof(task_t)+8; // for alignment
if (s_main.stack == NULL) { // first call, initialize all task subsystem
s_main.stack = (const uint8_t*)RAMEND - s_top; // remember bottom of stack of main task on first call
}
const uint8_t *sp=(const uint8_t*)s_main.prev->stack; // top of stack for new task
task_t *task=(task_t *) init_task(handle, sp); // give stack top as parameter, will correct later
sp-= stackSize; // calc stack bottom
task->stack = sp; // correct to bottom of stack
stack_bottom = (caddr_t)sp; // and remember for memory allocator
s_top += stackSize; // adjust used size at stack top
enqueue_task(*task); // task is ready, now we can add new task to run queue
// task will not be executed because .active==0
return (void *)task; // return address of task descriptor as task handle
}
// task should run periodically, period in uS. this will be high-priority task
void Scheduler::set_task_period(void *h, uint32_t period){
task_t *task = (task_t *)h;
task->active = false; // will be first started after 'period'
task->time_start = _micros();
task->period = period;
}
#ifdef SHED_DEBUG
static uint16_t next_log_ptr(uint16_t sched_log_ptr){
uint16_t lp = sched_log_ptr+ 1;
if(lp >= SHED_DEBUG_SIZE) lp=0;
return lp;
}
#endif
// exception occures in armed state - try to kill current task, or reboot if this is main task
void Scheduler::_try_kill_task_or_reboot(uint8_t n){
task_t *me = s_running; // current task
uint8_t tmp = task_n;
if(tmp==0 || me->id == 0) { // no tasks yet or in main task
board_set_rtc_register(FORCE_APP_RTC_SIGNATURE, RTC_SIGNATURE_REG); // force bootloader to not wait
_reboot(false);
}
stop_task(me); // exclude task from planning
task_n = 0; // printf() can call yield while we now between live and death
printf("\nTaks %d killed by exception %d!\n",me->id, n);
task_n = tmp;
next_task = get_next_task();
}
void Scheduler::_go_next_task() {
plan_context_switch();
while(1);
}
void Scheduler::_stop_multitask(){
task_n = 0;
}
// this function called only from SVC Level ISRs so there is no need to be reentrant
task_t *Scheduler::get_next_task(){
task_t *me = s_running; // current task
task_t *task=_idle_task; // task to switch to, idle_task by default
uint32_t timeFromLast=0;
uint32_t remains = 0;
uint32_t partial_quant=(uint32_t)-1;
task_t *want_tail = NULL;
uint32_t now = _micros();
me->t_yield = now;
#if defined(USE_MPU)
mpu_disable(); // we need access to all tasks
#endif
{ // isolate dt
#if defined(MTASK_PROF)
uint32_t dt = now - me->start; // time in task
if(dt >= me->in_isr) dt -= me->in_isr; // minus time in interrupts
else dt=0;
me->time+=dt; // calculate sum
me->quants_time+=dt;
#endif
#ifdef MTASK_PROF
if(dt > me->max_time) {
me->max_time = dt; // maximum to show
}
#ifdef SHED_DEBUG
{
revo_sched_log &lp = logbuf[sched_log_ptr];
lp.end = now;
lp.task_id=me->id;
lp.ttw = me->ttw;
lp.in_isr = me->in_isr;
lp.sw_type=me->sw_type;
sched_log_ptr = next_log_ptr(sched_log_ptr);
ZeroIt(logbuf[sched_log_ptr]); // clear next
}
#endif
#endif
}
if(_forced_task) {
task = _forced_task;
_forced_task = NULL;
} else {
task_t *ptr = me; // starting from current task
bool was_yield=false;
while(true) { // lets try to find task to switch to
ptr = ptr->next; // Next task in run queue will continue
#if !defined(USE_MPU) || 1
if(ptr->guard != STACK_GUARD){ // check for TCB is not damaged
printf("PANIC: stack guard spoiled in process %d (from %d)\n", task->id, me->id);
dequeue_task(*ptr); // исключить задачу из планирования
goto skip_task; // skip this tasks
}
#endif
if(!ptr->handle) goto skip_task; // skip finished tasks
if(ptr->f_yield) { // task wants to give one quant
ptr->f_yield = false;
was_yield = true;
goto skip_task; // skip this tasks
}
if(ptr->sem_wait) { // task want a semaphore
if(ptr->sem_wait->is_taken()) { // task blocked on semaphore
task_t *own =(task_t *)ptr->sem_wait->get_owner();
if(own != ptr) { // owner is another task?
uint32_t dt = now - ptr->sem_start_wait; // time since start waiting
if(ptr->sem_time == HAL_SEMAPHORE_BLOCK_FOREVER || dt < ptr->sem_time) {
if(own->curr_prio > ptr->curr_prio) {
own->curr_prio=ptr->curr_prio;
}
goto skip_task;
}
}
}
ptr->sem_wait=NULL; // clear semaphore after release
#ifdef MTASK_PROF
uint32_t st=now-ptr->sem_start_wait;
if(st>ptr->sem_max_wait) ptr->sem_max_wait=st; // time of semaphore waiting
#endif
}
if(!ptr->active){ // non-active, is it periodic?
if(ptr->period){
timeFromLast = now - ptr->time_start; // time from last run
if( timeFromLast < ptr->period) { // is less than task's period?
remains = ptr->period - timeFromLast;
if(remains>4) {
if(remains<partial_quant && ptr->curr_prio <= want_tail->curr_prio) { // exclude low-prio tasks
partial_quant=remains; // minimal time remains to next task
want_tail = ptr;
}
goto skip_task;
}// else execute task slightly before
}
} else { // non-active non-periodic tasks with manual activation
goto skip_task; // should be skipped
}
ptr->active=true; // selected task to run, even if it will lose quant by priority
} else { // обычный тайм слайс
if(ptr->ttw){// task wants to wait
timeFromLast = now - ptr->t_yield; // time since that moment
if(timeFromLast < ptr->ttw){ // still less than ttw ?
remains = ptr->ttw - timeFromLast; // remaining time to wait
if(remains>4) { // context switch time
if(remains<partial_quant && ptr->curr_prio <= want_tail->curr_prio) {
partial_quant=remains;
want_tail = ptr;
}
goto skip_task;
}// else execute task slightly before
}
}
}
if(ptr->curr_prio <= task->curr_prio){ // select the most priority task, round-robin for equal priorities
// task loose tick
if(task->priority != 255) { // not for idle task
if(task->curr_prio>1) task->curr_prio--; // increase priority if task loose tick
// as a result of the rising priority of the waiting task, we do not completely stop the low priority tasks, but only slow them down
// execution, forcing to skip the number of ticks equal to the priority difference. As a result, the low priority task is performed at a lower speed,
// which can be adjusted by changing the priority difference
}
task = ptr; // winner
} else { // ptr loose a chance - increase priority
if(ptr->priority != 255) { // not for idle task
if(ptr->curr_prio>1) ptr->curr_prio--;
}
}
skip_task:
// we should do this check after EACH task so can't use "continue" which skips ALL loop.
// And we can't move this to begin of loop because then interrupted task does not participate in the comparison of priorities
if(ptr == me) { // 'me' is the task that works now, so full loop - now we have most-priority task so let it run!
if(was_yield && task == _idle_task) { // task wants to yield() but there is no other tasks
was_yield=false; // reset flag and loop again
} else {
break; // task found
}
}
}
}
// task to run is selected
#ifdef SHED_DEBUG
revo_sched_log &lp = logbuf[sched_log_ptr];
lp.start = now;
lp.task_id=task->id;
lp.prio = task->curr_prio;
lp.active = task->active;
lp.time_start = task->time_start;
lp.quant = partial_quant;
lp.want_tail = want_tail;
ZeroIt(logbuf[next_log_ptr(sched_log_ptr)]); // clear next
#endif
task->curr_prio=task->priority; // reset current priority to default value
task->ttw=0; // time to wait is over
#if defined(MTASK_PROF)
task->start = now; // task startup time
task->in_isr=0; // reset ISR time
task->count++; // full count
task->quants++; // one-start count
uint32_t sz = s_running->sp - s_running->stack;
if(sz< s_running->stack_free) s_running->stack_free = sz;
#endif
if(want_tail && want_tail->curr_prio <= task->curr_prio) { // we have a high-prio task that want to be started next in the middle of tick
if(partial_quant < TIMER_PERIOD-10) { // if time less than tick
timer_set_count(TIMER14, 0);
timer_set_reload(TIMER14, partial_quant+2); // +2 to guarantee
timer_resume(TIMER14);
}
}
return task;
}
/*
interrupt to reduce timeslice quant
*/
void Scheduler::_tail_timer_event(uint32_t v /*TIM_TypeDef *tim */){
timer_pause(TIMER14); // stop tail timer
timer_generate_update(TIMER7); // tick is over
#ifndef MTASK_PROF
_switch_task();
#else
if(need_switch_task || task_n==0) return; // already scheduled context switch
next_task = get_next_task();
tsched_count_t++;
if(next_task != s_running) { // if we should switch task
s_running->sw_type=1;
tsched_sw_count_t++;
plan_context_switch();
}
#endif
}
void Scheduler::yield(uint16_t ttw) // time to wait
{
if(task_n==0 || in_interrupt()) { // SVC causes HardFault if in interrupt so just nothing to do
#ifdef USE_WFE
if(ttw) {__WFE(); }
#endif
return;
}
// if yield() called with a time, then task don't want to run all this time so exclude it from time sliceing
if(ttw) { // ttw cleared on sleep exit so always 0 if not set specially
s_running->ttw=ttw; // if switching tasks occurs between writing and calling svc, we just add an extra tick
}
asm volatile("svc 0");
}
/**
* Return current task stack size.
* @return bytes
*/
size_t Scheduler::task_stack(){
unsigned char marker;
return (&marker - s_running->stack);
}
// register IO completion routine
uint8_t Scheduler::register_io_completion(Handler handler){
if(num_io_completion < MAX_IO_COMPLETION){
io_completion[num_io_completion].handler=handler; // no need to disable interrupts because we increment counter later
io_completion[num_io_completion].request=false;
return ++num_io_completion;
}
return 0;
}
void Scheduler::_ioc_timer_event(uint32_t v){ // isr at low priority to do all IO completion routines
bool do_it = false;
#ifdef SHED_PROF
uint32_t full_t=_micros();
#endif
do {
do_it = false;
for(uint8_t i=0; i<num_io_completion; i++){
IO_Completion &io = io_completion[i];
if(io.request) {
io.request=false; // ASAP - it can be set again in interrupt.
// we don't need to disable interrupts because all drivers has own queue and can survive a skipping of one request
if(io.handler){
do_it=true;
#ifdef SHED_PROF
uint32_t t = _micros();
#endif
revo_call_handler(io.handler,i); // call it
#ifdef SHED_PROF
t = _micros() - t;
io.time += t;
io.count++;
if(t>io.max_time) io.max_time=t;
#endif
}
}
}
} while(do_it);
#ifdef SHED_PROF
full_t=_micros() - full_t;
ioc_time += full_t;
#endif
#ifdef MTASK_PROF
// To exclude the interruption time from the task's time, which it interrupted
s_running->in_isr += full_t;
#endif
}
#pragma GCC optimize ("O2") // should ALWAYS be -O2 for tail recursion optimization in PendSV_Handler
/* how to configure and schedule a PendSV exception
from http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0395b/CIHJHFJD.html
*/
void PendSV_Handler(){
Scheduler::need_switch_task=false;
#if defined(USE_MPU)
// set the guard page for the next task
mpu_configure_region(MPU_REGION_0,
(uint32_t)(next_task->stack) & ~31, // end of stack in the guard page
MPU_RASR_ATTR_AP_RO_RO | MPU_RASR_ATTR_NON_CACHEABLE | MPU_RASR_SIZE_32); // disable write access
mpu_enable(MPU_CTRL_PRIVDEFENA); // enable default memory map
#endif
__do_context_switch();
}
void SVC_Handler(){
uint32_t * svc_args;
// SVC can't be used from any interrupt so this is only for reliability
asm volatile (
"TST lr, #4 \n"
"ite eq \n"
"MRSEQ %0, MSP \n"
"MRSNE %0, PSP \n"
: "=rm" (svc_args) );
Scheduler::SVC_Handler(svc_args);
}
// svc executes on same priority as Timer7 ISR so there is no need to prevent interrupts
void Scheduler::SVC_Handler(uint32_t * svc_args){
// * Stack contains: * r0, r1, r2, r3, r12, r14, the return address and xPSR
unsigned int svc_number = ((char *)svc_args[6])[-2];
bool ret;
switch(svc_number) {
case 0: // Handle SVC 00 - yield()
timer_generate_update(TIMER7); // tick is over
timer_pause(TIMER14);
if(s_running->priority!=255){ // not for idle task or low-priority tasks
if(s_running->priority<IO_PRIORITY && s_running->ttw){ // the task voluntarily gave up its quant and wants delay, so that at the end of the delay it will have the high priority
s_running->curr_prio = s_running->priority - 6;
} else {
s_running->f_yield = true; // to guarantee that quant will not return even if there is no high priority tasks
}
}
switch_task();
break;
case 1:{ // Handle SVC 01 - semaphore give(semaphore) returns bool
Semaphore * sem = (F4Light::Semaphore *)svc_args[0];
bool v=sem->is_waiting();
svc_args[0] = sem->svc_give();
if(v) switch_task(); // switch context to waiting task if any
}
break;
case 2:{ // Handle SVC 02 - semaphore take(semaphore, time) returns bool
Semaphore * sem = (F4Light::Semaphore *)svc_args[0];
uint32_t timeout_ms = svc_args[1];
svc_args[0] = ret = sem->svc_take(timeout_ms);
if(!ret) { // if failed - switch context to pause waiting task
task_t *own = (task_t *)sem->get_owner();
task_t *curr_task = s_running;
curr_task->sem_wait = sem; // semaphore
curr_task->sem_start_wait = _micros(); // time when waiting starts
if(timeout_ms == HAL_SEMAPHORE_BLOCK_FOREVER){
curr_task->sem_time = timeout_ms;
} else {
curr_task->sem_time = timeout_ms*1000; // time to wait semaphore
}
//Increase the priority of the semaphore's owner up to the priority of the current task
if(own->priority >= curr_task->priority) own->curr_prio = curr_task->priority-1;
switch_task();
}
}
break;
case 3:{ // Handle SVC 03 - semaphore take_nonblocking(semaphore) returns bool
Semaphore * sem = (F4Light::Semaphore *)svc_args[0];
svc_args[0] = ret = sem->svc_take_nonblocking();
if(!ret) { // if failed - switch context to give tick to semaphore's owner
task_t *own = (task_t *)sem->get_owner();
task_t *curr_task = s_running;
//Increase the priority of the semaphore's owner up to the priority of the current task
if(own->priority >= curr_task->priority) own->curr_prio = curr_task->priority-1;
switch_task();
}
}
break;
case 4: // whats more we can do via SVC?
default: // Unknown SVC - just ignore
break;
}
}
// prepare task switch and plan it if needed. This function called only on ISR level 14
void Scheduler::switch_task(){
timer_pause(TIMER14); // we will recalculate scheduling
timer_generate_update(TIMER7); // tick is over
_switch_task();
}
void Scheduler::_switch_task(){
if(need_switch_task || task_n==0) return; // already scheduled context switch
next_task = get_next_task(); // 2.5uS mean full time
#ifdef MTASK_PROF
tsched_count_y++;
#endif
if(next_task != s_running) { // if we should switch task
#ifdef MTASK_PROF
s_running->sw_type=2;
tsched_sw_count_y++;
#endif
plan_context_switch();
}
#ifdef MTASK_PROF
else if(next_task == _idle_task){ // the same idle task
tsched_count_y--; // don't count loops in idle task
}
#endif
}
////////////////////////////////////
/*
union Revo_handler { // blood, bowels, assembler :) transform functors into a unified view for calling from C
voidFuncPtr vp;
AP_HAL::MemberProc mp; this is C not C ++, so we can not declare the support of functors explicitly, and are forced to pass
uint64_t h; // treat as handle <-- as 64-bit integer
uint32_t w[2]; // words, to check. if this is a functor then the high is the address of the flash and the lower one is the address in RAM.
if this is a function pointer then lower word is an address in flash and high is 0
};
*/
void revo_call_handler(uint64_t hh, uint32_t arg){
Revo_handler h = { .h = hh };
if(ADDRESS_IN_FLASH(h.w[0])){
(h.isr)(arg);
} else if(ADDRESS_IN_FLASH(h.w[1])) {
(h.mpa)(arg);
}
}
void hal_yield(uint16_t ttw){ Scheduler::yield(ttw); }
void hal_delay(uint16_t t){ Scheduler::_delay(t); }
void hal_delay_microseconds(uint16_t t){ Scheduler::_delay_microseconds(t);}
uint32_t hal_micros() { return Scheduler::_micros(); }
void hal_isr_time(uint32_t t) { s_running->in_isr += t; }
// task management for USB and another C code
void hal_set_task_active(void * h) { Scheduler::set_task_active(h); }
void hal_context_switch_isr() { Scheduler::context_switch_isr(); }
void hal_set_task_priority(void * h, uint8_t prio) {Scheduler::set_task_priority(h, prio); }
void * hal_register_task(voidFuncPtr task, uint32_t stack) {
Revo_handler r = { .vp=task };
return Scheduler::_start_task(r.h, stack);
}
bool hal_is_armed() { return hal.util->get_soft_armed(); }
void hal_try_kill_task_or_reboot(uint8_t n) { Scheduler::_try_kill_task_or_reboot(n); }
void hal_go_next_task() { Scheduler::_go_next_task(); }
void hal_stop_multitask() { Scheduler::_stop_multitask(); }