circuitpython/shared/runtime/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/gc.h"
#include "py/mphal.h"
#include "py/runtime.h"
#include "softtimer.h"
extern __IO uint32_t MICROPY_SOFT_TIMER_TICKS_MS;
volatile uint32_t soft_timer_next;
// Pointer to the pairheap of soft timer objects.
// This may contain bss/data pointers as well as GC-heap pointers,
// and is explicitly GC traced by soft_timer_gc_mark_all().
STATIC soft_timer_entry_t *soft_timer_heap;
static inline int32_t ticks_diff(uint32_t t1, uint32_t t0) {
// t1 is after t0 (i.e. positive result) if there exists a uint32_t X <= INT_MAX
// such that t0 + X = t1. Otherwise t1 is interpreted to be earlier than
// t0 (negative result).
return t1 - t0;
}
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 = MICROPY_SOFT_TIMER_TICKS_MS;
if (ticks_diff(ticks_ms, uw_tick) <= 0) {
soft_timer_next = uw_tick + 1;
} else {
soft_timer_next = ticks_ms;
}
enable_irq(irq_state);
}
void soft_timer_deinit(void) {
// Pop off all the nodes which are allocated on the GC-heap.
uint32_t irq_state = raise_irq_pri(IRQ_PRI_PENDSV);
soft_timer_entry_t *heap_from = soft_timer_heap;
soft_timer_entry_t *heap_to = (soft_timer_entry_t *)mp_pairheap_new(soft_timer_lt);
while (heap_from != NULL) {
soft_timer_entry_t *entry = (soft_timer_entry_t *)mp_pairheap_peek(soft_timer_lt, &heap_from->pairheap);
heap_from = (soft_timer_entry_t *)mp_pairheap_pop(soft_timer_lt, &heap_from->pairheap);
if (!(entry->flags & SOFT_TIMER_FLAG_GC_ALLOCATED)) {
heap_to = (soft_timer_entry_t *)mp_pairheap_push(soft_timer_lt, &heap_to->pairheap, &entry->pairheap);
}
}
soft_timer_heap = heap_to;
restore_irq_pri(irq_state);
}
// Must be executed at IRQ_PRI_PENDSV
void soft_timer_handler(void) {
uint32_t ticks_ms = MICROPY_SOFT_TIMER_TICKS_MS;
soft_timer_entry_t *heap = 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);
if (entry->flags & SOFT_TIMER_FLAG_PY_CALLBACK) {
mp_sched_schedule(entry->py_callback, MP_OBJ_FROM_PTR(entry));
} else {
entry->c_callback(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);
}
}
soft_timer_heap = heap;
if (heap == NULL) {
// No more timers left, set largest delay possible
soft_timer_next = MICROPY_SOFT_TIMER_TICKS_MS;
} else {
// Set soft_timer_next so SysTick calls us back at the correct time
soft_timer_schedule_systick(heap->expiry_ms);
}
}
void soft_timer_gc_mark_all(void) {
// Mark all soft timer nodes that are allocated on the GC-heap.
// To avoid deep C recursion, pop and recreate the pairheap as nodes are marked.
uint32_t irq_state = raise_irq_pri(IRQ_PRI_PENDSV);
soft_timer_entry_t *heap_from = soft_timer_heap;
soft_timer_entry_t *heap_to = (soft_timer_entry_t *)mp_pairheap_new(soft_timer_lt);
while (heap_from != NULL) {
soft_timer_entry_t *entry = (soft_timer_entry_t *)mp_pairheap_peek(soft_timer_lt, &heap_from->pairheap);
heap_from = (soft_timer_entry_t *)mp_pairheap_pop(soft_timer_lt, &heap_from->pairheap);
if (entry->flags & SOFT_TIMER_FLAG_GC_ALLOCATED) {
gc_collect_root((void **)&entry, 1);
}
heap_to = (soft_timer_entry_t *)mp_pairheap_push(soft_timer_lt, &heap_to->pairheap, &entry->pairheap);
}
soft_timer_heap = heap_to;
restore_irq_pri(irq_state);
}
void soft_timer_static_init(soft_timer_entry_t *entry, uint16_t mode, uint32_t delta_ms, void (*cb)(soft_timer_entry_t *)) {
mp_pairheap_init_node(soft_timer_lt, &entry->pairheap);
entry->flags = 0;
entry->mode = mode;
entry->delta_ms = delta_ms;
entry->c_callback = cb;
}
void soft_timer_insert(soft_timer_entry_t *entry, uint32_t initial_delta_ms) {
mp_pairheap_init_node(soft_timer_lt, &entry->pairheap);
entry->expiry_ms = MICROPY_SOFT_TIMER_TICKS_MS + initial_delta_ms;
uint32_t irq_state = raise_irq_pri(IRQ_PRI_PENDSV);
soft_timer_heap = (soft_timer_entry_t *)mp_pairheap_push(soft_timer_lt, &soft_timer_heap->pairheap, &entry->pairheap);
if (entry == 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);
soft_timer_heap = (soft_timer_entry_t *)mp_pairheap_delete(soft_timer_lt, &soft_timer_heap->pairheap, &entry->pairheap);
restore_irq_pri(irq_state);
}