222 lines
8.1 KiB
C
222 lines
8.1 KiB
C
/*
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* This file is part of the MicroPython project, http://micropython.org/
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*
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* The MIT License (MIT)
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*
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* Copyright (c) 2017 Damien P. George
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include <stdio.h>
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#include "py/runtime.h"
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// Schedules an exception on the main thread (for exceptions "thrown" by async
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// sources such as interrupts and UNIX signal handlers).
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void MICROPY_WRAP_MP_SCHED_EXCEPTION(mp_sched_exception)(mp_obj_t exc) {
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MP_STATE_MAIN_THREAD(mp_pending_exception) = exc;
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#if MICROPY_ENABLE_SCHEDULER && !MICROPY_PY_THREAD
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// Optimisation for the case where we have scheduler but no threading.
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// Allows the VM to do a single check to exclude both pending exception
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// and queued tasks.
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if (MP_STATE_VM(sched_state) == MP_SCHED_IDLE) {
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MP_STATE_VM(sched_state) = MP_SCHED_PENDING;
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}
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#endif
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}
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#if MICROPY_KBD_EXCEPTION
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// This function may be called asynchronously at any time so only do the bare minimum.
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void MICROPY_WRAP_MP_SCHED_KEYBOARD_INTERRUPT(mp_sched_keyboard_interrupt)(void) {
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MP_STATE_VM(mp_kbd_exception).traceback_data = NULL;
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mp_sched_exception(MP_OBJ_FROM_PTR(&MP_STATE_VM(mp_kbd_exception)));
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}
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#endif
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#if MICROPY_ENABLE_SCHEDULER
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#define IDX_MASK(i) ((i) & (MICROPY_SCHEDULER_DEPTH - 1))
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// This is a macro so it is guaranteed to be inlined in functions like
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// mp_sched_schedule that may be located in a special memory region.
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#define mp_sched_full() (mp_sched_num_pending() == MICROPY_SCHEDULER_DEPTH)
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static inline bool mp_sched_empty(void) {
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MP_STATIC_ASSERT(MICROPY_SCHEDULER_DEPTH <= 255); // MICROPY_SCHEDULER_DEPTH must fit in 8 bits
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MP_STATIC_ASSERT((IDX_MASK(MICROPY_SCHEDULER_DEPTH) == 0)); // MICROPY_SCHEDULER_DEPTH must be a power of 2
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return mp_sched_num_pending() == 0;
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}
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static inline void mp_sched_run_pending(void) {
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mp_uint_t atomic_state = MICROPY_BEGIN_ATOMIC_SECTION();
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if (MP_STATE_VM(sched_state) != MP_SCHED_PENDING) {
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// Something else (e.g. hard IRQ) locked the scheduler while we
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// acquired the lock.
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MICROPY_END_ATOMIC_SECTION(atomic_state);
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return;
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}
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// Equivalent to mp_sched_lock(), but we're already in the atomic
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// section and know that we're pending.
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MP_STATE_VM(sched_state) = MP_SCHED_LOCKED;
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#if MICROPY_SCHEDULER_STATIC_NODES
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// Run all pending C callbacks.
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while (MP_STATE_VM(sched_head) != NULL) {
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mp_sched_node_t *node = MP_STATE_VM(sched_head);
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MP_STATE_VM(sched_head) = node->next;
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if (MP_STATE_VM(sched_head) == NULL) {
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MP_STATE_VM(sched_tail) = NULL;
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}
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mp_sched_callback_t callback = node->callback;
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node->callback = NULL;
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MICROPY_END_ATOMIC_SECTION(atomic_state);
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callback(node);
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atomic_state = MICROPY_BEGIN_ATOMIC_SECTION();
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}
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#endif
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// Run at most one pending Python callback.
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if (!mp_sched_empty()) {
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mp_sched_item_t item = MP_STATE_VM(sched_queue)[MP_STATE_VM(sched_idx)];
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MP_STATE_VM(sched_idx) = IDX_MASK(MP_STATE_VM(sched_idx) + 1);
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--MP_STATE_VM(sched_len);
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MICROPY_END_ATOMIC_SECTION(atomic_state);
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mp_call_function_1_protected(item.func, item.arg);
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} else {
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MICROPY_END_ATOMIC_SECTION(atomic_state);
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}
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// Restore MP_STATE_VM(sched_state) to idle (or pending if there are still
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// tasks in the queue).
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mp_sched_unlock();
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}
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// Locking the scheduler prevents tasks from executing (does not prevent new
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// tasks from being added). We lock the scheduler while executing scheduled
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// tasks and also in hard interrupts or GC finalisers.
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void mp_sched_lock(void) {
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mp_uint_t atomic_state = MICROPY_BEGIN_ATOMIC_SECTION();
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if (MP_STATE_VM(sched_state) < 0) {
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// Already locked, increment lock (recursive lock).
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--MP_STATE_VM(sched_state);
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} else {
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// Pending or idle.
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MP_STATE_VM(sched_state) = MP_SCHED_LOCKED;
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}
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MICROPY_END_ATOMIC_SECTION(atomic_state);
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}
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void mp_sched_unlock(void) {
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mp_uint_t atomic_state = MICROPY_BEGIN_ATOMIC_SECTION();
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assert(MP_STATE_VM(sched_state) < 0);
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if (++MP_STATE_VM(sched_state) == 0) {
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// Scheduler became unlocked. Check if there are still tasks in the
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// queue and set sched_state accordingly.
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if (
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#if !MICROPY_PY_THREAD
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// See optimisation in mp_sched_exception.
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MP_STATE_THREAD(mp_pending_exception) != MP_OBJ_NULL ||
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#endif
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#if MICROPY_SCHEDULER_STATIC_NODES
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MP_STATE_VM(sched_head) != NULL ||
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#endif
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mp_sched_num_pending()) {
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MP_STATE_VM(sched_state) = MP_SCHED_PENDING;
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} else {
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MP_STATE_VM(sched_state) = MP_SCHED_IDLE;
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}
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}
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MICROPY_END_ATOMIC_SECTION(atomic_state);
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}
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bool MICROPY_WRAP_MP_SCHED_SCHEDULE(mp_sched_schedule)(mp_obj_t function, mp_obj_t arg) {
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mp_uint_t atomic_state = MICROPY_BEGIN_ATOMIC_SECTION();
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bool ret;
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if (!mp_sched_full()) {
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if (MP_STATE_VM(sched_state) == MP_SCHED_IDLE) {
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MP_STATE_VM(sched_state) = MP_SCHED_PENDING;
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}
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uint8_t iput = IDX_MASK(MP_STATE_VM(sched_idx) + MP_STATE_VM(sched_len)++);
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MP_STATE_VM(sched_queue)[iput].func = function;
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MP_STATE_VM(sched_queue)[iput].arg = arg;
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MICROPY_SCHED_HOOK_SCHEDULED;
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ret = true;
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} else {
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// schedule queue is full
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ret = false;
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}
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MICROPY_END_ATOMIC_SECTION(atomic_state);
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return ret;
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}
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#if MICROPY_SCHEDULER_STATIC_NODES
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bool mp_sched_schedule_node(mp_sched_node_t *node, mp_sched_callback_t callback) {
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mp_uint_t atomic_state = MICROPY_BEGIN_ATOMIC_SECTION();
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bool ret;
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if (node->callback == NULL) {
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if (MP_STATE_VM(sched_state) == MP_SCHED_IDLE) {
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MP_STATE_VM(sched_state) = MP_SCHED_PENDING;
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}
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node->callback = callback;
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node->next = NULL;
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if (MP_STATE_VM(sched_tail) == NULL) {
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MP_STATE_VM(sched_head) = node;
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} else {
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MP_STATE_VM(sched_tail)->next = node;
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}
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MP_STATE_VM(sched_tail) = node;
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MICROPY_SCHED_HOOK_SCHEDULED;
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ret = true;
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} else {
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// already scheduled
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ret = false;
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}
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MICROPY_END_ATOMIC_SECTION(atomic_state);
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return ret;
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}
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#endif
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#endif // MICROPY_ENABLE_SCHEDULER
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// Called periodically from the VM or from "waiting" code (e.g. sleep) to
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// process background tasks and pending exceptions (e.g. KeyboardInterrupt).
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void mp_handle_pending(bool raise_exc) {
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if (MP_STATE_THREAD(mp_pending_exception) != MP_OBJ_NULL) {
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mp_uint_t atomic_state = MICROPY_BEGIN_ATOMIC_SECTION();
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mp_obj_t obj = MP_STATE_THREAD(mp_pending_exception);
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if (obj != MP_OBJ_NULL) {
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MP_STATE_THREAD(mp_pending_exception) = MP_OBJ_NULL;
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if (raise_exc) {
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MICROPY_END_ATOMIC_SECTION(atomic_state);
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nlr_raise(obj);
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}
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}
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MICROPY_END_ATOMIC_SECTION(atomic_state);
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}
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#if MICROPY_ENABLE_SCHEDULER
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if (MP_STATE_VM(sched_state) == MP_SCHED_PENDING) {
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mp_sched_run_pending();
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}
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#endif
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}
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