circuitpython/supervisor/shared/background_callback.c

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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2020 Jeff Epler for Adafruit Industries
*
* 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 <string.h>
#include "py/gc.h"
#include "py/mpconfig.h"
#include "supervisor/background_callback.h"
#include "supervisor/linker.h"
#include "supervisor/port.h"
#include "supervisor/shared/tick.h"
#include "shared-bindings/microcontroller/__init__.h"
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STATIC volatile background_callback_t *volatile callback_head, *volatile callback_tail;
#define CALLBACK_CRITICAL_BEGIN (common_hal_mcu_disable_interrupts())
#define CALLBACK_CRITICAL_END (common_hal_mcu_enable_interrupts())
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MP_WEAK void port_wake_main_task(void) {
}
void background_callback_add_core(background_callback_t *cb) {
CALLBACK_CRITICAL_BEGIN;
if (cb->prev || callback_head == cb) {
CALLBACK_CRITICAL_END;
return;
}
cb->next = 0;
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cb->prev = (background_callback_t *)callback_tail;
if (callback_tail) {
callback_tail->next = cb;
}
if (!callback_head) {
callback_head = cb;
}
callback_tail = cb;
CALLBACK_CRITICAL_END;
port_wake_main_task();
}
void background_callback_add(background_callback_t *cb, background_callback_fun fun, void *data) {
cb->fun = fun;
cb->data = data;
background_callback_add_core(cb);
}
bool PLACE_IN_ITCM(background_callback_pending)(void) {
return callback_head != NULL;
}
static bool in_background_callback;
void PLACE_IN_ITCM(background_callback_run_all)() {
if (!background_callback_pending()) {
return;
}
CALLBACK_CRITICAL_BEGIN;
if (in_background_callback) {
CALLBACK_CRITICAL_END;
return;
}
in_background_callback = true;
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background_callback_t *cb = (background_callback_t *)callback_head;
callback_head = NULL;
callback_tail = NULL;
while (cb) {
background_callback_t *next = cb->next;
cb->next = cb->prev = NULL;
background_callback_fun fun = cb->fun;
void *data = cb->data;
CALLBACK_CRITICAL_END;
// Leave the critical section in order to run the callback function
if (fun) {
fun(data);
}
CALLBACK_CRITICAL_BEGIN;
cb = next;
}
in_background_callback = false;
CALLBACK_CRITICAL_END;
}
void background_callback_begin_critical_section() {
CALLBACK_CRITICAL_BEGIN;
}
void background_callback_end_critical_section() {
CALLBACK_CRITICAL_END;
}
void background_callback_reset() {
CALLBACK_CRITICAL_BEGIN;
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background_callback_t *cb = (background_callback_t *)callback_head;
while (cb) {
background_callback_t *next = cb->next;
memset(cb, 0, sizeof(*cb));
cb = next;
}
callback_head = NULL;
callback_tail = NULL;
in_background_callback = false;
CALLBACK_CRITICAL_END;
}
void background_callback_gc_collect(void) {
// We don't enter the callback critical section here. We rely on
// gc_collect_ptr _NOT_ entering background callbacks, so it is not
// possible for the list to be cleared.
//
// However, it is possible for the list to be extended. We make the
// minor assumption that no newly added callback is for a
// collectable object. That is, we only plug the hole where an
// object becomes collectable AFTER it is added but before the
// callback is run, not the hole where an object was ALREADY
// collectable but adds a background task for itself.
//
// It's necessary to traverse the whole list here, as the callbacks
// themselves can be in non-gc memory, and some of the cb->data
// objects themselves might be in non-gc memory.
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background_callback_t *cb = (background_callback_t *)callback_head;
while (cb) {
gc_collect_ptr(cb->data);
cb = cb->next;
}
}