Lancaster University / mbed-src

Lancaster University's (short term!) clone of mbed-src for micro:bit. This is a copy of the github branch https://github.com/lancaster-university/mbed-classic

Fork of mbed-src by mbed official

common/InterruptManager.cpp@641:be9b2017785a, 2016-07-13 (annotated)

Committer:
LancasterUniversity
Date:
Wed Jul 13 12:52:54 2016 +0100
Revision:
641:be9b2017785a
Parent:
390:35c2c1cf29cd 
Synchronized with git rev 1fb8ab4c

Author: James Devine

mbed-classic: BUGFIX for timer when using wait_ms from interrupt context



Previously if a user used wait[_ms,_us] in interrupt context the device would

hang indefinitely. This was due to incrementing overflowCount from

interrupt context only.



This meant that if a user used wait[_ms,_us] in an ISR with

the same or greater interrupt priority, it would result in an infinite

loop as the overflowCount variable would never be incremented, and

wait[_ms,_us] would never return.



This patch simply applies a better solution for the race condition

mentioned in the previous commit. It instead disables the timer1

interrupt and increments the overflowCount variable, preventing

the race condition whilst supporting wait[_ms,_us] in interrupt

context.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mbed_official 390:35c2c1cf29cd 1 #include "cmsis.h"
mbed_official 390:35c2c1cf29cd 2 #if defined(NVIC_NUM_VECTORS)
mbed_official 390:35c2c1cf29cd 3
bogdanm 15:4892fe388435 4 #include "InterruptManager.h"
bogdanm 15:4892fe388435 5 #include <string.h>
bogdanm 15:4892fe388435 6
bogdanm 15:4892fe388435 7 #define CHAIN_INITIAL_SIZE 4
bogdanm 15:4892fe388435 8
bogdanm 15:4892fe388435 9 namespace mbed {
bogdanm 15:4892fe388435 10
bogdanm 15:4892fe388435 11 typedef void (*pvoidf)(void);
bogdanm 15:4892fe388435 12
mbed_official 262:85569914dbe0 13 InterruptManager* InterruptManager::_instance = (InterruptManager*)NULL;
bogdanm 15:4892fe388435 14
bogdanm 15:4892fe388435 15 InterruptManager* InterruptManager::get() {
bogdanm 15:4892fe388435 16 if (NULL == _instance)
bogdanm 15:4892fe388435 17 _instance = new InterruptManager();
bogdanm 15:4892fe388435 18 return _instance;
bogdanm 15:4892fe388435 19 }
bogdanm 15:4892fe388435 20
bogdanm 15:4892fe388435 21 InterruptManager::InterruptManager() {
bogdanm 15:4892fe388435 22 memset(_chains, 0, NVIC_NUM_VECTORS * sizeof(CallChain*));
bogdanm 15:4892fe388435 23 }
bogdanm 15:4892fe388435 24
bogdanm 15:4892fe388435 25 void InterruptManager::destroy() {
bogdanm 15:4892fe388435 26 // Not a good idea to call this unless NO interrupt at all
bogdanm 15:4892fe388435 27 // is under the control of the handler; otherwise, a system crash
bogdanm 15:4892fe388435 28 // is very likely to occur
bogdanm 15:4892fe388435 29 if (NULL != _instance) {
bogdanm 15:4892fe388435 30 delete _instance;
mbed_official 262:85569914dbe0 31 _instance = (InterruptManager*)NULL;
bogdanm 15:4892fe388435 32 }
bogdanm 15:4892fe388435 33 }
bogdanm 15:4892fe388435 34
bogdanm 15:4892fe388435 35 InterruptManager::~InterruptManager() {
bogdanm 15:4892fe388435 36 for(int i = 0; i < NVIC_NUM_VECTORS; i++)
bogdanm 15:4892fe388435 37 if (NULL != _chains[i])
bogdanm 15:4892fe388435 38 delete _chains[i];
bogdanm 15:4892fe388435 39 }
bogdanm 15:4892fe388435 40
bogdanm 15:4892fe388435 41 bool InterruptManager::must_replace_vector(IRQn_Type irq) {
bogdanm 15:4892fe388435 42 int irq_pos = get_irq_index(irq);
bogdanm 15:4892fe388435 43
bogdanm 15:4892fe388435 44 if (NULL == _chains[irq_pos]) {
bogdanm 15:4892fe388435 45 _chains[irq_pos] = new CallChain(CHAIN_INITIAL_SIZE);
bogdanm 15:4892fe388435 46 _chains[irq_pos]->add((pvoidf)NVIC_GetVector(irq));
bogdanm 15:4892fe388435 47 return true;
bogdanm 15:4892fe388435 48 }
bogdanm 15:4892fe388435 49 return false;
bogdanm 15:4892fe388435 50 }
bogdanm 15:4892fe388435 51
bogdanm 15:4892fe388435 52 pFunctionPointer_t InterruptManager::add_common(void (*function)(void), IRQn_Type irq, bool front) {
bogdanm 15:4892fe388435 53 int irq_pos = get_irq_index(irq);
bogdanm 15:4892fe388435 54 bool change = must_replace_vector(irq);
bogdanm 15:4892fe388435 55
bogdanm 15:4892fe388435 56 pFunctionPointer_t pf = front ? _chains[irq_pos]->add_front(function) : _chains[irq_pos]->add(function);
bogdanm 15:4892fe388435 57 if (change)
bogdanm 15:4892fe388435 58 NVIC_SetVector(irq, (uint32_t)&InterruptManager::static_irq_helper);
bogdanm 15:4892fe388435 59 return pf;
bogdanm 15:4892fe388435 60 }
bogdanm 15:4892fe388435 61
bogdanm 15:4892fe388435 62 bool InterruptManager::remove_handler(pFunctionPointer_t handler, IRQn_Type irq) {
bogdanm 15:4892fe388435 63 int irq_pos = get_irq_index(irq);
mbed_official 221:8276e3a4886f 64
bogdanm 15:4892fe388435 65 if (NULL == _chains[irq_pos])
bogdanm 15:4892fe388435 66 return false;
bogdanm 15:4892fe388435 67 if (!_chains[irq_pos]->remove(handler))
bogdanm 15:4892fe388435 68 return false;
bogdanm 15:4892fe388435 69 // If there's a single function left in the chain, swith the interrupt vector
bogdanm 15:4892fe388435 70 // to call that function directly. This way we save both time and space.
bogdanm 15:4892fe388435 71 if (_chains[irq_pos]->size() == 1 && NULL != _chains[irq_pos]->get(0)->get_function()) {
bogdanm 15:4892fe388435 72 NVIC_SetVector(irq, (uint32_t)_chains[irq_pos]->get(0)->get_function());
bogdanm 15:4892fe388435 73 delete _chains[irq_pos];
mbed_official 262:85569914dbe0 74 _chains[irq_pos] = (CallChain*) NULL;
bogdanm 15:4892fe388435 75 }
bogdanm 15:4892fe388435 76 return true;
bogdanm 15:4892fe388435 77 }
bogdanm 15:4892fe388435 78
bogdanm 15:4892fe388435 79 void InterruptManager::irq_helper() {
bogdanm 15:4892fe388435 80 _chains[__get_IPSR()]->call();
bogdanm 15:4892fe388435 81 }
bogdanm 15:4892fe388435 82
bogdanm 15:4892fe388435 83 int InterruptManager::get_irq_index(IRQn_Type irq) {
bogdanm 15:4892fe388435 84 return (int)irq + NVIC_USER_IRQ_OFFSET;
bogdanm 15:4892fe388435 85 }
bogdanm 15:4892fe388435 86
bogdanm 15:4892fe388435 87 void InterruptManager::static_irq_helper() {
bogdanm 15:4892fe388435 88 InterruptManager::get()->irq_helper();
bogdanm 15:4892fe388435 89 }
bogdanm 15:4892fe388435 90
bogdanm 15:4892fe388435 91 } // namespace mbed
bogdanm 15:4892fe388435 92
mbed_official 390:35c2c1cf29cd 93 #endif