| /* |
| * 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 "py/mpstate.h" |
| #include "py/runtime.h" |
| #include "lib/utils/interrupt_char.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_kbd_exception 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_kbd_intr(void) { |
| if (MP_STATE_VM(mp_pending_exception) == MP_OBJ_NULL) { |
| mp_keyboard_interrupt(); |
| } else { |
| MP_STATE_VM(mp_pending_exception) = MP_OBJ_NULL; |
| pendsv_object = &MP_STATE_VM(mp_kbd_exception); |
| 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=r15 |
| // sp[5]: lr=r14 |
| // sp[4]: r12 |
| // sp[3]: r3 |
| // sp[2]: r2 |
| // sp[1]: r1 |
| // sp[0]: r0 |
| // |
| // stack layout with DEBUG enabled: |
| // sp[8]: pc=r15 |
| // sp[7]: lr=r14 |
| // sp[6]: r12 |
| // sp[5]: r3 |
| // sp[4]: r2 |
| // sp[3]: r1 |
| // sp[2]: r0 |
| // sp[1]: 0xfffffff9 |
| // sp[0]: ? |
| |
| #if MICROPY_PY_THREAD |
| __asm volatile ( |
| "ldr r1, pendsv_object_ptr\n" |
| "ldr r0, [r1]\n" |
| "cmp r0, 0\n" |
| "beq .no_obj\n" |
| "str r0, [sp, #0]\n" // store to r0 on stack |
| "mov r0, #0\n" |
| "str r0, [r1]\n" // clear pendsv_object |
| "ldr r0, nlr_jump_ptr\n" |
| "str r0, [sp, #24]\n" // store to pc on stack |
| "bx lr\n" // return from interrupt; will return to nlr_jump |
| |
| ".no_obj:\n" // pendsv_object==NULL |
| "push {r4-r11, lr}\n" |
| "vpush {s16-s31}\n" |
| "mrs r5, primask\n" // save PRIMASK in r5 |
| "cpsid i\n" // disable interrupts while we change stacks |
| "mov r0, sp\n" // pass sp to save |
| "mov r4, lr\n" // save lr because we are making a call |
| "bl pyb_thread_next\n" // get next thread to execute |
| "mov lr, r4\n" // restore lr |
| "mov sp, r0\n" // switch stacks |
| "msr primask, r5\n" // reenable interrupts |
| "vpop {s16-s31}\n" |
| "pop {r4-r11, lr}\n" |
| "bx lr\n" // return from interrupt; will return to new thread |
| ".align 2\n" |
| "pendsv_object_ptr: .word pendsv_object\n" |
| "nlr_jump_ptr: .word nlr_jump\n" |
| ); |
| #else |
| __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" |
| ); |
| #endif |
| |
| /* |
| 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]); |
| } |
| */ |
| } |