micropython/ports/rp2/pendsv.c

103 wiersze
3.5 KiB
C

/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2022 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 <assert.h>
#include "pico/mutex.h"
#include "py/mpconfig.h"
#include "pendsv.h"
#include "RP2040.h"
#if MICROPY_PY_NETWORK_CYW43
#include "lib/cyw43-driver/src/cyw43_stats.h"
#endif
static pendsv_dispatch_t pendsv_dispatch_table[PENDSV_DISPATCH_NUM_SLOTS];
static recursive_mutex_t pendsv_mutex;
void pendsv_init(void) {
recursive_mutex_init(&pendsv_mutex);
}
void pendsv_suspend(void) {
// Recursive Mutex here as either core may call pendsv_suspend() and expect
// both mutual exclusion (other core can't enter pendsv_suspend() at the
// same time), and that no PendSV handler will run.
recursive_mutex_enter_blocking(&pendsv_mutex);
}
void pendsv_resume(void) {
recursive_mutex_exit(&pendsv_mutex);
// Run pendsv if needed. Find an entry with a dispatch and call pendsv dispatch
// with it. If pendsv runs it will service all slots.
int count = PENDSV_DISPATCH_NUM_SLOTS;
while (count--) {
if (pendsv_dispatch_table[count]) {
pendsv_schedule_dispatch(count, pendsv_dispatch_table[count]);
break;
}
}
}
void pendsv_schedule_dispatch(size_t slot, pendsv_dispatch_t f) {
pendsv_dispatch_table[slot] = f;
if (pendsv_mutex.enter_count == 0) {
// There is a race here where other core calls pendsv_suspend() before
// ISR can execute, but dispatch will happen later when other core
// calls pendsv_resume().
SCB->ICSR = SCB_ICSR_PENDSVSET_Msk;
} else {
#if MICROPY_PY_NETWORK_CYW43
CYW43_STAT_INC(PENDSV_DISABLED_COUNT);
#endif
}
}
// PendSV interrupt handler to perform background processing.
void PendSV_Handler(void) {
if (!recursive_mutex_try_enter(&pendsv_mutex, NULL)) {
// Failure here means core 1 holds pendsv_mutex. ISR will
// run again after core 1 calls pendsv_resume().
return;
}
// Core 0 should not already have locked pendsv_mutex
assert(pensv_mutex.enter_count == 1);
#if MICROPY_PY_NETWORK_CYW43
CYW43_STAT_INC(PENDSV_RUN_COUNT);
#endif
for (size_t i = 0; i < PENDSV_DISPATCH_NUM_SLOTS; ++i) {
if (pendsv_dispatch_table[i] != NULL) {
pendsv_dispatch_t f = pendsv_dispatch_table[i];
pendsv_dispatch_table[i] = NULL;
f();
}
}
recursive_mutex_exit(&pendsv_mutex);
}