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

Committer:
LancasterUniversity
Date:
Wed Jul 13 12:52:54 2016 +0100
Revision:
641:be9b2017785a
Parent:
212:34d62c0b2af6 
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
bogdanm 13:0645d8841f51 1 /* mbed Microcontroller Library
bogdanm 13:0645d8841f51 2 * Copyright (c) 2006-2013 ARM Limited
bogdanm 13:0645d8841f51 3 *
bogdanm 13:0645d8841f51 4 * Licensed under the Apache License, Version 2.0 (the "License");
bogdanm 13:0645d8841f51 5 * you may not use this file except in compliance with the License.
bogdanm 13:0645d8841f51 6 * You may obtain a copy of the License at
bogdanm 13:0645d8841f51 7 *
bogdanm 13:0645d8841f51 8 * http://www.apache.org/licenses/LICENSE-2.0
bogdanm 13:0645d8841f51 9 *
bogdanm 13:0645d8841f51 10 * Unless required by applicable law or agreed to in writing, software
bogdanm 13:0645d8841f51 11 * distributed under the License is distributed on an "AS IS" BASIS,
bogdanm 13:0645d8841f51 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
bogdanm 13:0645d8841f51 13 * See the License for the specific language governing permissions and
bogdanm 13:0645d8841f51 14 * limitations under the License.
bogdanm 13:0645d8841f51 15 */
bogdanm 13:0645d8841f51 16 #include "FileBase.h"
bogdanm 13:0645d8841f51 17
bogdanm 13:0645d8841f51 18 namespace mbed {
bogdanm 13:0645d8841f51 19
bogdanm 13:0645d8841f51 20 FileBase *FileBase::_head = NULL;
bogdanm 13:0645d8841f51 21
mbed_official 212:34d62c0b2af6 22 FileBase::FileBase(const char *name, PathType t) : _next(NULL),
mbed_official 212:34d62c0b2af6 23 _name(name),
mbed_official 212:34d62c0b2af6 24 _path_type(t) {
bogdanm 13:0645d8841f51 25 if (name != NULL) {
bogdanm 13:0645d8841f51 26 // put this object at head of the list
bogdanm 13:0645d8841f51 27 _next = _head;
bogdanm 13:0645d8841f51 28 _head = this;
bogdanm 13:0645d8841f51 29 } else {
bogdanm 13:0645d8841f51 30 _next = NULL;
bogdanm 13:0645d8841f51 31 }
bogdanm 13:0645d8841f51 32 }
bogdanm 13:0645d8841f51 33
bogdanm 13:0645d8841f51 34 FileBase::~FileBase() {
bogdanm 13:0645d8841f51 35 if (_name != NULL) {
bogdanm 13:0645d8841f51 36 // remove this object from the list
bogdanm 13:0645d8841f51 37 if (_head == this) { // first in the list, so just drop me
bogdanm 13:0645d8841f51 38 _head = _next;
bogdanm 13:0645d8841f51 39 } else { // find the object before me, then drop me
bogdanm 13:0645d8841f51 40 FileBase *p = _head;
bogdanm 13:0645d8841f51 41 while (p->_next != this) {
bogdanm 13:0645d8841f51 42 p = p->_next;
bogdanm 13:0645d8841f51 43 }
bogdanm 13:0645d8841f51 44 p->_next = _next;
bogdanm 13:0645d8841f51 45 }
bogdanm 13:0645d8841f51 46 }
bogdanm 13:0645d8841f51 47 }
bogdanm 13:0645d8841f51 48
bogdanm 13:0645d8841f51 49 FileBase *FileBase::lookup(const char *name, unsigned int len) {
bogdanm 13:0645d8841f51 50 FileBase *p = _head;
bogdanm 13:0645d8841f51 51 while (p != NULL) {
bogdanm 13:0645d8841f51 52 /* Check that p->_name matches name and is the correct length */
bogdanm 13:0645d8841f51 53 if (p->_name != NULL && std::strncmp(p->_name, name, len) == 0 && std::strlen(p->_name) == len) {
bogdanm 13:0645d8841f51 54 return p;
bogdanm 13:0645d8841f51 55 }
bogdanm 13:0645d8841f51 56 p = p->_next;
bogdanm 13:0645d8841f51 57 }
bogdanm 13:0645d8841f51 58 return NULL;
bogdanm 13:0645d8841f51 59 }
bogdanm 13:0645d8841f51 60
bogdanm 13:0645d8841f51 61 FileBase *FileBase::get(int n) {
bogdanm 13:0645d8841f51 62 FileBase *p = _head;
bogdanm 13:0645d8841f51 63 int m = 0;
bogdanm 13:0645d8841f51 64 while (p != NULL) {
bogdanm 13:0645d8841f51 65 if (m == n) return p;
bogdanm 13:0645d8841f51 66
bogdanm 13:0645d8841f51 67 m++;
bogdanm 13:0645d8841f51 68 p = p->_next;
bogdanm 13:0645d8841f51 69 }
bogdanm 13:0645d8841f51 70 return NULL;
bogdanm 13:0645d8841f51 71 }
bogdanm 13:0645d8841f51 72
bogdanm 13:0645d8841f51 73 const char* FileBase::getName(void) {
bogdanm 13:0645d8841f51 74 return _name;
bogdanm 13:0645d8841f51 75 }
bogdanm 13:0645d8841f51 76
bogdanm 13:0645d8841f51 77 PathType FileBase::getPathType(void) {
bogdanm 13:0645d8841f51 78 return _path_type;
bogdanm 13:0645d8841f51 79 }
bogdanm 13:0645d8841f51 80
bogdanm 13:0645d8841f51 81 } // namespace mbed
bogdanm 13:0645d8841f51 82