circuitpython/ports/stm32/softtimer.c

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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2019 Damien P. George
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include <stdint.h>
#include "py/runtime.h"
#include "irq.h"
#include "softtimer.h"
#define TICKS_PERIOD 0x80000000
#define TICKS_DIFF(t1, t0) ((int32_t)(((t1 - t0 + TICKS_PERIOD / 2) & (TICKS_PERIOD - 1)) - TICKS_PERIOD / 2))
extern __IO uint32_t uwTick;
volatile uint32_t soft_timer_next;
void soft_timer_deinit(void) {
MP_STATE_PORT(soft_timer_heap) = NULL;
}
STATIC int soft_timer_lt(mp_pairheap_t *n1, mp_pairheap_t *n2) {
soft_timer_entry_t *e1 = (soft_timer_entry_t *)n1;
soft_timer_entry_t *e2 = (soft_timer_entry_t *)n2;
return TICKS_DIFF(e1->expiry_ms, e2->expiry_ms) < 0;
}
STATIC void soft_timer_schedule_systick(uint32_t ticks_ms) {
uint32_t irq_state = disable_irq();
uint32_t uw_tick = uwTick;
if (TICKS_DIFF(ticks_ms, uw_tick) <= 0) {
soft_timer_next = uw_tick + 1;
} else {
soft_timer_next = ticks_ms;
}
enable_irq(irq_state);
}
// Must be executed at IRQ_PRI_PENDSV
void soft_timer_handler(void) {
uint32_t ticks_ms = uwTick;
soft_timer_entry_t *heap = MP_STATE_PORT(soft_timer_heap);
while (heap != NULL && TICKS_DIFF(heap->expiry_ms, ticks_ms) <= 0) {
soft_timer_entry_t *entry = heap;
heap = (soft_timer_entry_t *)mp_pairheap_pop(soft_timer_lt, &heap->pairheap);
mp_sched_schedule(entry->callback, MP_OBJ_FROM_PTR(entry));
if (entry->mode == SOFT_TIMER_MODE_PERIODIC) {
entry->expiry_ms += entry->delta_ms;
heap = (soft_timer_entry_t *)mp_pairheap_push(soft_timer_lt, &heap->pairheap, &entry->pairheap);
}
}
MP_STATE_PORT(soft_timer_heap) = heap;
if (heap == NULL) {
// No more timers left, set largest delay possible
soft_timer_next = uwTick;
} else {
// Set soft_timer_next so SysTick calls us back at the correct time
soft_timer_schedule_systick(heap->expiry_ms);
}
}
void soft_timer_insert(soft_timer_entry_t *entry) {
uint32_t irq_state = raise_irq_pri(IRQ_PRI_PENDSV);
MP_STATE_PORT(soft_timer_heap) = (soft_timer_entry_t *)mp_pairheap_push(soft_timer_lt, &MP_STATE_PORT(soft_timer_heap)->pairheap, &entry->pairheap);
if (entry == MP_STATE_PORT(soft_timer_heap)) {
// This new timer became the earliest one so set soft_timer_next
soft_timer_schedule_systick(entry->expiry_ms);
}
restore_irq_pri(irq_state);
}
void soft_timer_remove(soft_timer_entry_t *entry) {
uint32_t irq_state = raise_irq_pri(IRQ_PRI_PENDSV);
MP_STATE_PORT(soft_timer_heap) = (soft_timer_entry_t *)mp_pairheap_delete(soft_timer_lt, &MP_STATE_PORT(soft_timer_heap)->pairheap, &entry->pairheap);
restore_irq_pri(irq_state);
}