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119 lines (111 loc) · 4.08 KB
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/*
* This file is part of the Micro Python project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2013, 2014 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 <stdlib.h>
#include STM32_HAL_H
#include "py/mpstate.h"
#include "py/runtime.h"
#include "pendsv.h"
#include "irq.h"
// This variable is used to save the exception object between a ctrl-C and the
// PENDSV call that actually raises the exception. It must be non-static
// otherwise gcc-5 optimises it away. It can point to the heap but is not
// traced by GC. This is okay because we only ever set it to
// mp_const_vcp_interrupt which is in the root-pointer set.
void *pendsv_object;
void pendsv_init(void) {
// set PendSV interrupt at lowest priority
HAL_NVIC_SetPriority(PendSV_IRQn, IRQ_PRI_PENDSV, IRQ_SUBPRI_PENDSV);
}
// Call this function to raise a pending exception during an interrupt.
// It will first try to raise the exception "softly" by setting the
// mp_pending_exception variable and hoping that the VM will notice it.
// If this function is called a second time (ie with the mp_pending_exception
// variable already set) then it will force the exception by using the hardware
// PENDSV feature. This will wait until all interrupts are finished then raise
// the given exception object using nlr_jump in the context of the top-level
// thread.
void pendsv_nlr_jump(void *o) {
if (MP_STATE_VM(mp_pending_exception) == MP_OBJ_NULL) {
MP_STATE_VM(mp_pending_exception) = o;
} else {
MP_STATE_VM(mp_pending_exception) = MP_OBJ_NULL;
pendsv_object = o;
SCB->ICSR = SCB_ICSR_PENDSVSET_Msk;
}
}
void pendsv_isr_handler(void) {
// re-jig the stack so that when we return from this interrupt handler
// it returns instead to nlr_jump with argument pendsv_object
// note that stack has a different layout if DEBUG is enabled
//
// on entry to this (naked) function, stack has the following layout:
//
// stack layout with DEBUG disabled:
// sp[6]: pc
// sp[5]: ?
// sp[4]: ?
// sp[3]: ?
// sp[2]: ?
// sp[1]: ?
// sp[0]: r0
//
// stack layout with DEBUG enabled:
// sp[8]: pc
// sp[7]: lr
// sp[6]: ?
// sp[5]: ?
// sp[4]: ?
// sp[3]: ?
// sp[2]: r0
// sp[1]: 0xfffffff9
// sp[0]: ?
__asm volatile (
"ldr r0, pendsv_object_ptr\n"
"ldr r0, [r0]\n"
#if defined(PENDSV_DEBUG)
"str r0, [sp, #8]\n"
#else
"str r0, [sp, #0]\n"
#endif
"ldr r0, nlr_jump_ptr\n"
#if defined(PENDSV_DEBUG)
"str r0, [sp, #32]\n"
#else
"str r0, [sp, #24]\n"
#endif
"bx lr\n"
".align 2\n"
"pendsv_object_ptr: .word pendsv_object\n"
"nlr_jump_ptr: .word nlr_jump\n"
);
/*
uint32_t x[2] = {0x424242, 0xdeaddead};
printf("PendSV: %p\n", x);
for (uint32_t *p = (uint32_t*)(((uint32_t)x - 15) & 0xfffffff0), i = 64; i > 0; p += 4, i -= 4) {
printf(" %p: %08x %08x %08x %08x\n", p, (uint)p[0], (uint)p[1], (uint)p[2], (uint)p[3]);
}
*/
}