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micropython/stmhal/pybthread.c

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stmhal: Initial implementation of multithreading, currently disabled. This patch brings the _thread module to stmhal/pyboard. There is a very simple round-robin thread scheduler, which is disabled if there is only one thread (for efficiency when threading is not used). The scheduler currently switches threads at a rate of 250Hz using the systick timer and the pend-SV interrupt. The GIL is disabled so one must be careful to use lock objects to prevent concurrent access of objects. The threading is disabled by default, one can enabled it with the config option MICROPY_PY_THREAD to test it out.
2017-01-31 02:59:53 +00:00
/*
* 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
stmhal: Implement a proper thread scheduler. This patch changes the threading implementation from simple round-robin with busy waits on mutexs, to proper scheduling whereby threads that are waiting on a mutex are only scheduled when the mutex becomes available.
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#define PYB_MUTEX_UNLOCKED ((void*)0)
#define PYB_MUTEX_LOCKED ((void*)1)
stmhal/pybthread: Allow interrupts to work during lock/unlock of mutex. When locking/unlocking a mutex we only need to protect against a thread switch, not general interrupts.
2017-03-22 01:44:04 +00:00
// 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)
stmhal: Implement a proper thread scheduler. This patch changes the threading implementation from simple round-robin with busy waits on mutexs, to proper scheduling whereby threads that are waiting on a mutex are only scheduled when the mutex becomes available.
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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;
}
stmhal: Initial implementation of multithreading, currently disabled. This patch brings the _thread module to stmhal/pyboard. There is a very simple round-robin thread scheduler, which is disabled if there is only one thread (for efficiency when threading is not used). The scheduler currently switches threads at a rate of 250Hz using the systick timer and the pend-SV interrupt. The GIL is disabled so one must be careful to use lock objects to prevent concurrent access of objects. The threading is disabled by default, one can enabled it with the config option MICROPY_PY_THREAD to test it out.
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void pyb_thread_init(pyb_thread_t *thread) {
stmhal: Implement a proper thread scheduler. This patch changes the threading implementation from simple round-robin with busy waits on mutexs, to proper scheduling whereby threads that are waiting on a mutex are only scheduled when the mutex becomes available.
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pyb_thread_enabled = 0;
pyb_thread_all = thread;
stmhal: Initial implementation of multithreading, currently disabled. This patch brings the _thread module to stmhal/pyboard. There is a very simple round-robin thread scheduler, which is disabled if there is only one thread (for efficiency when threading is not used). The scheduler currently switches threads at a rate of 250Hz using the systick timer and the pend-SV interrupt. The GIL is disabled so one must be careful to use lock objects to prevent concurrent access of objects. The threading is disabled by default, one can enabled it with the config option MICROPY_PY_THREAD to test it out.
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pyb_thread_cur = thread;
stmhal: Implement a proper thread scheduler. This patch changes the threading implementation from simple round-robin with busy waits on mutexs, to proper scheduling whereby threads that are waiting on a mutex are only scheduled when the mutex becomes available.
2017-02-06 04:13:30 +00:00
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 = &_heap_end;
thread->stack_len = ((uint32_t)&_estack - (uint32_t)&_heap_end) / 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);
stmhal: Initial implementation of multithreading, currently disabled. This patch brings the _thread module to stmhal/pyboard. There is a very simple round-robin thread scheduler, which is disabled if there is only one thread (for efficiency when threading is not used). The scheduler currently switches threads at a rate of 250Hz using the systick timer and the pend-SV interrupt. The GIL is disabled so one must be careful to use lock objects to prevent concurrent access of objects. The threading is disabled by default, one can enabled it with the config option MICROPY_PY_THREAD to test it out.
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}
STATIC void pyb_thread_terminate(void) {
stmhal: Implement a proper thread scheduler. This patch changes the threading implementation from simple round-robin with busy waits on mutexs, to proper scheduling whereby threads that are waiting on a mutex are only scheduled when the mutex becomes available.
2017-02-06 04:13:30 +00:00
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
stmhal: Initial implementation of multithreading, currently disabled. This patch brings the _thread module to stmhal/pyboard. There is a very simple round-robin thread scheduler, which is disabled if there is only one thread (for efficiency when threading is not used). The scheduler currently switches threads at a rate of 250Hz using the systick timer and the pend-SV interrupt. The GIL is disabled so one must be careful to use lock objects to prevent concurrent access of objects. The threading is disabled by default, one can enabled it with the config option MICROPY_PY_THREAD to test it out.
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pyb_thread_enabled = 0;
}
stmhal: Implement a proper thread scheduler. This patch changes the threading implementation from simple round-robin with busy waits on mutexs, to proper scheduling whereby threads that are waiting on a mutex are only scheduled when the mutex becomes available.
2017-02-06 04:13:30 +00:00
// 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");
stmhal: Initial implementation of multithreading, currently disabled. This patch brings the _thread module to stmhal/pyboard. There is a very simple round-robin thread scheduler, which is disabled if there is only one thread (for efficiency when threading is not used). The scheduler currently switches threads at a rate of 250Hz using the systick timer and the pend-SV interrupt. The GIL is disabled so one must be careful to use lock objects to prevent concurrent access of objects. The threading is disabled by default, one can enabled it with the config option MICROPY_PY_THREAD to test it out.
2017-01-31 02:59:53 +00:00
}
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;
stmhal: Implement a proper thread scheduler. This patch changes the threading implementation from simple round-robin with busy waits on mutexs, to proper scheduling whereby threads that are waiting on a mutex are only scheduled when the mutex becomes available.
2017-02-06 04:13:30 +00:00
thread->queue_next = NULL;
uint32_t irq_state = disable_irq();
stmhal: Initial implementation of multithreading, currently disabled. This patch brings the _thread module to stmhal/pyboard. There is a very simple round-robin thread scheduler, which is disabled if there is only one thread (for efficiency when threading is not used). The scheduler currently switches threads at a rate of 250Hz using the systick timer and the pend-SV interrupt. The GIL is disabled so one must be careful to use lock objects to prevent concurrent access of objects. The threading is disabled by default, one can enabled it with the config option MICROPY_PY_THREAD to test it out.
2017-01-31 02:59:53 +00:00
pyb_thread_enabled = 1;
stmhal: Implement a proper thread scheduler. This patch changes the threading implementation from simple round-robin with busy waits on mutexs, to proper scheduling whereby threads that are waiting on a mutex are only scheduled when the mutex becomes available.
2017-02-06 04:13:30 +00:00
thread->all_next = pyb_thread_all;
pyb_thread_all = thread;
pyb_thread_add_to_runable(thread);
enable_irq(irq_state);
stmhal: Initial implementation of multithreading, currently disabled. This patch brings the _thread module to stmhal/pyboard. There is a very simple round-robin thread scheduler, which is disabled if there is only one thread (for efficiency when threading is not used). The scheduler currently switches threads at a rate of 250Hz using the systick timer and the pend-SV interrupt. The GIL is disabled so one must be careful to use lock objects to prevent concurrent access of objects. The threading is disabled by default, one can enabled it with the config option MICROPY_PY_THREAD to test it out.
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return (uint32_t)thread; // success
}
stmhal: Implement a proper thread scheduler. This patch changes the threading implementation from simple round-robin with busy waits on mutexs, to proper scheduling whereby threads that are waiting on a mutex are only scheduled when the mutex becomes available.
2017-02-06 04:13:30 +00:00
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");
}
}
}
stmhal: Initial implementation of multithreading, currently disabled. This patch brings the _thread module to stmhal/pyboard. There is a very simple round-robin thread scheduler, which is disabled if there is only one thread (for efficiency when threading is not used). The scheduler currently switches threads at a rate of 250Hz using the systick timer and the pend-SV interrupt. The GIL is disabled so one must be careful to use lock objects to prevent concurrent access of objects. The threading is disabled by default, one can enabled it with the config option MICROPY_PY_THREAD to test it out.
2017-01-31 02:59:53 +00:00
// should only be called from pendsv_isr_handler
void *pyb_thread_next(void *sp) {
pyb_thread_cur->sp = sp;
stmhal: Implement a proper thread scheduler. This patch changes the threading implementation from simple round-robin with busy waits on mutexs, to proper scheduling whereby threads that are waiting on a mutex are only scheduled when the mutex becomes available.
2017-02-06 04:13:30 +00:00
pyb_thread_cur = pyb_thread_cur->run_next;
pyb_thread_cur->timeslice = 4; // in milliseconds
stmhal: Initial implementation of multithreading, currently disabled. This patch brings the _thread module to stmhal/pyboard. There is a very simple round-robin thread scheduler, which is disabled if there is only one thread (for efficiency when threading is not used). The scheduler currently switches threads at a rate of 250Hz using the systick timer and the pend-SV interrupt. The GIL is disabled so one must be careful to use lock objects to prevent concurrent access of objects. The threading is disabled by default, one can enabled it with the config option MICROPY_PY_THREAD to test it out.
2017-01-31 02:59:53 +00:00
return pyb_thread_cur->sp;
}
stmhal: Implement a proper thread scheduler. This patch changes the threading implementation from simple round-robin with busy waits on mutexs, to proper scheduling whereby threads that are waiting on a mutex are only scheduled when the mutex becomes available.
2017-02-06 04:13:30 +00:00
void pyb_mutex_init(pyb_mutex_t *m) {
*m = PYB_MUTEX_UNLOCKED;
}
int pyb_mutex_lock(pyb_mutex_t *m, int wait) {
stmhal/pybthread: Allow interrupts to work during lock/unlock of mutex. When locking/unlocking a mutex we only need to protect against a thread switch, not general interrupts.
2017-03-22 01:44:04 +00:00
uint32_t irq_state = RAISE_IRQ_PRI();
stmhal: Implement a proper thread scheduler. This patch changes the threading implementation from simple round-robin with busy waits on mutexs, to proper scheduling whereby threads that are waiting on a mutex are only scheduled when the mutex becomes available.
2017-02-06 04:13:30 +00:00
if (*m == PYB_MUTEX_UNLOCKED) {
// mutex is available
*m = PYB_MUTEX_LOCKED;
stmhal/pybthread: Allow interrupts to work during lock/unlock of mutex. When locking/unlocking a mutex we only need to protect against a thread switch, not general interrupts.
2017-03-22 01:44:04 +00:00
RESTORE_IRQ_PRI(irq_state);
stmhal: Implement a proper thread scheduler. This patch changes the threading implementation from simple round-robin with busy waits on mutexs, to proper scheduling whereby threads that are waiting on a mutex are only scheduled when the mutex becomes available.
2017-02-06 04:13:30 +00:00
} else {
// mutex is locked
if (!wait) {
stmhal/pybthread: Allow interrupts to work during lock/unlock of mutex. When locking/unlocking a mutex we only need to protect against a thread switch, not general interrupts.
2017-03-22 01:44:04 +00:00
RESTORE_IRQ_PRI(irq_state);
stmhal: Implement a proper thread scheduler. This patch changes the threading implementation from simple round-robin with busy waits on mutexs, to proper scheduling whereby threads that are waiting on a mutex are only scheduled when the mutex becomes available.
2017-02-06 04:13:30 +00:00
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;
stmhal/pybthread: Allow interrupts to work during lock/unlock of mutex. When locking/unlocking a mutex we only need to protect against a thread switch, not general interrupts.
2017-03-22 01:44:04 +00:00
RESTORE_IRQ_PRI(irq_state);
stmhal: Implement a proper thread scheduler. This patch changes the threading implementation from simple round-robin with busy waits on mutexs, to proper scheduling whereby threads that are waiting on a mutex are only scheduled when the mutex becomes available.
2017-02-06 04:13:30 +00:00
// when we come back we have the mutex
}
return 1; // have mutex
}
void pyb_mutex_unlock(pyb_mutex_t *m) {
stmhal/pybthread: Allow interrupts to work during lock/unlock of mutex. When locking/unlocking a mutex we only need to protect against a thread switch, not general interrupts.
2017-03-22 01:44:04 +00:00
uint32_t irq_state = RAISE_IRQ_PRI();
stmhal: Implement a proper thread scheduler. This patch changes the threading implementation from simple round-robin with busy waits on mutexs, to proper scheduling whereby threads that are waiting on a mutex are only scheduled when the mutex becomes available.
2017-02-06 04:13:30 +00:00
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);
}
stmhal/pybthread: Allow interrupts to work during lock/unlock of mutex. When locking/unlocking a mutex we only need to protect against a thread switch, not general interrupts.
2017-03-22 01:44:04 +00:00
RESTORE_IRQ_PRI(irq_state);
stmhal: Implement a proper thread scheduler. This patch changes the threading implementation from simple round-robin with busy waits on mutexs, to proper scheduling whereby threads that are waiting on a mutex are only scheduled when the mutex becomes available.
2017-02-06 04:13:30 +00:00
}
stmhal: Initial implementation of multithreading, currently disabled. This patch brings the _thread module to stmhal/pyboard. There is a very simple round-robin thread scheduler, which is disabled if there is only one thread (for efficiency when threading is not used). The scheduler currently switches threads at a rate of 250Hz using the systick timer and the pend-SV interrupt. The GIL is disabled so one must be careful to use lock objects to prevent concurrent access of objects. The threading is disabled by default, one can enabled it with the config option MICROPY_PY_THREAD to test it out.
2017-01-31 02:59:53 +00:00
#endif // MICROPY_PY_THREAD