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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2017 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 <string.h>
#include <stdio.h>
#include "py/obj.h"
#include "gccollect.h"
#include "irq.h"
#include "pybthread.h"
#if MICROPY_PY_THREAD
#define PYB_MUTEX_UNLOCKED ((void*)0)
#define PYB_MUTEX_LOCKED ((void*)1)
// These macros are used when we only need to protect against a thread
// switch; other interrupts are still allowed to proceed.
#define RAISE_IRQ_PRI() raise_irq_pri(IRQ_PRI_PENDSV)
#define RESTORE_IRQ_PRI(state) restore_irq_pri(state)
extern void __fatal_error(const char*);
volatile int pyb_thread_enabled;
pyb_thread_t *volatile pyb_thread_all;
pyb_thread_t *volatile pyb_thread_cur;
static inline void pyb_thread_add_to_runable(pyb_thread_t *thread) {
thread->run_prev = pyb_thread_cur->run_prev;
thread->run_next = pyb_thread_cur;
pyb_thread_cur->run_prev->run_next = thread;
pyb_thread_cur->run_prev = thread;
}
static inline void pyb_thread_remove_from_runable(pyb_thread_t *thread) {
if (thread->run_next == thread) {
__fatal_error("deadlock");
}
thread->run_prev->run_next = thread->run_next;
thread->run_next->run_prev = thread->run_prev;
}
void pyb_thread_init(pyb_thread_t *thread) {
pyb_thread_enabled = 0;
pyb_thread_all = thread;
pyb_thread_cur = thread;
thread->sp = NULL; // will be set when this thread switches out
thread->local_state = 0; // will be set by mp_thread_init
thread->arg = NULL;
thread->stack = &_sstack;
thread->stack_len = ((uint32_t)&_estack - (uint32_t)&_sstack) / sizeof(uint32_t);
thread->all_next = NULL;
thread->run_prev = thread;
thread->run_next = thread;
thread->queue_next = NULL;
}
void pyb_thread_deinit() {
uint32_t irq_state = disable_irq();
pyb_thread_enabled = 0;
pyb_thread_all = pyb_thread_cur;
pyb_thread_cur->all_next = NULL;
pyb_thread_cur->run_prev = pyb_thread_cur;
pyb_thread_cur->run_next = pyb_thread_cur;
enable_irq(irq_state);
}
STATIC void pyb_thread_terminate(void) {
uint32_t irq_state = disable_irq();
pyb_thread_t *thread = pyb_thread_cur;
// take current thread off the run list
pyb_thread_remove_from_runable(thread);
// take current thread off the list of all threads
for (pyb_thread_t **n = (pyb_thread_t**)&pyb_thread_all;; n = &(*n)->all_next) {
if (*n == thread) {
*n = thread->all_next;
break;
}
}
// clean pointers as much as possible to help GC
thread->all_next = NULL;
thread->queue_next = NULL;
thread->stack = NULL;
if (pyb_thread_all->all_next == NULL) {
// only 1 thread left
pyb_thread_enabled = 0;
}
// thread switch will occur after we enable irqs
SCB->ICSR = SCB_ICSR_PENDSVSET_Msk;
enable_irq(irq_state);
// should not return
__fatal_error("could not terminate");
}
uint32_t pyb_thread_new(pyb_thread_t *thread, void *stack, size_t stack_len, void *entry, void *arg) {
uint32_t *stack_top = (uint32_t*)stack + stack_len; // stack is full descending
*--stack_top = 0x01000000; // xPSR (thumb bit set)
*--stack_top = (uint32_t)entry & 0xfffffffe; // pc (must have bit 0 cleared, even for thumb code)
*--stack_top = (uint32_t)pyb_thread_terminate; // lr
*--stack_top = 0; // r12
*--stack_top = 0; // r3
*--stack_top = 0; // r2
*--stack_top = 0; // r1
*--stack_top = (uint32_t)arg; // r0
*--stack_top = 0xfffffff9; // lr (return to thread mode, non-FP, use MSP)
stack_top -= 8; // r4-r11
stack_top -= 16; // s16-s31 (we assume all threads use FP registers)
thread->sp = stack_top;
thread->local_state = 0;
thread->arg = arg;
thread->stack = stack;
thread->stack_len = stack_len;
thread->queue_next = NULL;
uint32_t irq_state = disable_irq();
pyb_thread_enabled = 1;
thread->all_next = pyb_thread_all;
pyb_thread_all = thread;
pyb_thread_add_to_runable(thread);
enable_irq(irq_state);
return (uint32_t)thread; // success
}
void pyb_thread_dump(void) {
if (!pyb_thread_enabled) {
printf("THREAD: only main thread\n");
} else {
printf("THREAD:\n");
for (pyb_thread_t *th = pyb_thread_all; th != NULL; th = th->all_next) {
bool runable = false;
for (pyb_thread_t *th2 = pyb_thread_cur;; th2 = th2->run_next) {
if (th == th2) {
runable = true;
break;
}
if (th2->run_next == pyb_thread_cur) {
break;
}
}
printf(" id=%p sp=%p sz=%u", th, th->stack, th->stack_len);
if (runable) {
printf(" (runable)");
}
printf("\n");
}
}
}
// should only be called from pendsv_isr_handler
void *pyb_thread_next(void *sp) {
pyb_thread_cur->sp = sp;
pyb_thread_cur = pyb_thread_cur->run_next;
pyb_thread_cur->timeslice = 4; // in milliseconds
return pyb_thread_cur->sp;
}
void pyb_mutex_init(pyb_mutex_t *m) {
*m = PYB_MUTEX_UNLOCKED;
}
int pyb_mutex_lock(pyb_mutex_t *m, int wait) {
uint32_t irq_state = RAISE_IRQ_PRI();
if (*m == PYB_MUTEX_UNLOCKED) {
// mutex is available
*m = PYB_MUTEX_LOCKED;
RESTORE_IRQ_PRI(irq_state);
} else {
// mutex is locked
if (!wait) {
RESTORE_IRQ_PRI(irq_state);
return 0; // failed to lock mutex
}
if (*m == PYB_MUTEX_LOCKED) {
*m = pyb_thread_cur;
} else {
for (pyb_thread_t *n = *m;; n = n->queue_next) {
if (n->queue_next == NULL) {
n->queue_next = pyb_thread_cur;
break;
}
}
}
pyb_thread_cur->queue_next = NULL;
// take current thread off the run list
pyb_thread_remove_from_runable(pyb_thread_cur);
// thread switch will occur after we enable irqs
SCB->ICSR = SCB_ICSR_PENDSVSET_Msk;
RESTORE_IRQ_PRI(irq_state);
// when we come back we have the mutex
}
return 1; // have mutex
}
void pyb_mutex_unlock(pyb_mutex_t *m) {
uint32_t irq_state = RAISE_IRQ_PRI();
if (*m == PYB_MUTEX_LOCKED) {
// no threads are blocked on the mutex
*m = PYB_MUTEX_UNLOCKED;
} else {
// at least one thread is blocked on this mutex
pyb_thread_t *th = *m;
if (th->queue_next == NULL) {
// no other threads are blocked
*m = PYB_MUTEX_LOCKED;
} else {
// at least one other thread is still blocked
*m = th->queue_next;
}
// put unblocked thread on runable list
pyb_thread_add_to_runable(th);
}
RESTORE_IRQ_PRI(irq_state);
}
#endif // MICROPY_PY_THREAD
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