Lancaster University / mbed-src

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

Committer:
LancasterUniversity
Date:
Wed Jul 13 12:52:54 2016 +0100
Revision:
641:be9b2017785a
Parent:
431:255afbe6270c 
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 "Stream.h"
bogdanm 13:0645d8841f51 17
bogdanm 13:0645d8841f51 18 #include <cstdarg>
bogdanm 13:0645d8841f51 19
bogdanm 13:0645d8841f51 20 namespace mbed {
bogdanm 13:0645d8841f51 21
mbed_official 212:34d62c0b2af6 22 Stream::Stream(const char *name) : FileLike(name), _file(NULL) {
bogdanm 13:0645d8841f51 23 /* open ourselves */
bogdanm 13:0645d8841f51 24 char buf[12]; /* :0x12345678 + null byte */
bogdanm 13:0645d8841f51 25 std::sprintf(buf, ":%p", this);
bogdanm 13:0645d8841f51 26 _file = std::fopen(buf, "w+");
mbed_official 431:255afbe6270c 27 mbed_set_unbuffered_stream(_file);
bogdanm 13:0645d8841f51 28 }
bogdanm 13:0645d8841f51 29
bogdanm 13:0645d8841f51 30 Stream::~Stream() {
bogdanm 13:0645d8841f51 31 fclose(_file);
bogdanm 13:0645d8841f51 32 }
bogdanm 13:0645d8841f51 33
bogdanm 13:0645d8841f51 34 int Stream::putc(int c) {
bogdanm 13:0645d8841f51 35 fflush(_file);
bogdanm 13:0645d8841f51 36 return std::fputc(c, _file);
bogdanm 13:0645d8841f51 37 }
bogdanm 13:0645d8841f51 38 int Stream::puts(const char *s) {
bogdanm 13:0645d8841f51 39 fflush(_file);
bogdanm 13:0645d8841f51 40 return std::fputs(s, _file);
bogdanm 13:0645d8841f51 41 }
bogdanm 13:0645d8841f51 42 int Stream::getc() {
bogdanm 13:0645d8841f51 43 fflush(_file);
mbed_official 431:255afbe6270c 44 return mbed_getc(_file);
bogdanm 13:0645d8841f51 45 }
bogdanm 13:0645d8841f51 46 char* Stream::gets(char *s, int size) {
bogdanm 13:0645d8841f51 47 fflush(_file);
mbed_official 431:255afbe6270c 48 return mbed_gets(s,size,_file);
bogdanm 13:0645d8841f51 49 }
bogdanm 13:0645d8841f51 50
bogdanm 13:0645d8841f51 51 int Stream::close() {
bogdanm 13:0645d8841f51 52 return 0;
bogdanm 13:0645d8841f51 53 }
bogdanm 13:0645d8841f51 54
bogdanm 13:0645d8841f51 55 ssize_t Stream::write(const void* buffer, size_t length) {
bogdanm 13:0645d8841f51 56 const char* ptr = (const char*)buffer;
bogdanm 13:0645d8841f51 57 const char* end = ptr + length;
bogdanm 13:0645d8841f51 58 while (ptr != end) {
bogdanm 13:0645d8841f51 59 if (_putc(*ptr++) == EOF) {
bogdanm 13:0645d8841f51 60 break;
bogdanm 13:0645d8841f51 61 }
bogdanm 13:0645d8841f51 62 }
bogdanm 13:0645d8841f51 63 return ptr - (const char*)buffer;
bogdanm 13:0645d8841f51 64 }
bogdanm 13:0645d8841f51 65
bogdanm 13:0645d8841f51 66 ssize_t Stream::read(void* buffer, size_t length) {
bogdanm 13:0645d8841f51 67 char* ptr = (char*)buffer;
bogdanm 13:0645d8841f51 68 char* end = ptr + length;
bogdanm 13:0645d8841f51 69 while (ptr != end) {
bogdanm 13:0645d8841f51 70 int c = _getc();
bogdanm 13:0645d8841f51 71 if (c==EOF) break;
bogdanm 13:0645d8841f51 72 *ptr++ = c;
bogdanm 13:0645d8841f51 73 }
bogdanm 13:0645d8841f51 74 return ptr - (const char*)buffer;
bogdanm 13:0645d8841f51 75 }
bogdanm 13:0645d8841f51 76
bogdanm 13:0645d8841f51 77 off_t Stream::lseek(off_t offset, int whence) {
bogdanm 13:0645d8841f51 78 return 0;
bogdanm 13:0645d8841f51 79 }
bogdanm 13:0645d8841f51 80
bogdanm 13:0645d8841f51 81 int Stream::isatty() {
bogdanm 13:0645d8841f51 82 return 0;
bogdanm 13:0645d8841f51 83 }
bogdanm 13:0645d8841f51 84
bogdanm 13:0645d8841f51 85 int Stream::fsync() {
bogdanm 13:0645d8841f51 86 return 0;
bogdanm 13:0645d8841f51 87 }
bogdanm 13:0645d8841f51 88
bogdanm 13:0645d8841f51 89 off_t Stream::flen() {
bogdanm 13:0645d8841f51 90 return 0;
bogdanm 13:0645d8841f51 91 }
bogdanm 13:0645d8841f51 92
bogdanm 13:0645d8841f51 93 int Stream::printf(const char* format, ...) {
bogdanm 13:0645d8841f51 94 std::va_list arg;
bogdanm 13:0645d8841f51 95 va_start(arg, format);
bogdanm 13:0645d8841f51 96 fflush(_file);
bogdanm 13:0645d8841f51 97 int r = vfprintf(_file, format, arg);
bogdanm 13:0645d8841f51 98 va_end(arg);
bogdanm 13:0645d8841f51 99 return r;
bogdanm 13:0645d8841f51 100 }
bogdanm 13:0645d8841f51 101
bogdanm 13:0645d8841f51 102 int Stream::scanf(const char* format, ...) {
bogdanm 13:0645d8841f51 103 std::va_list arg;
bogdanm 13:0645d8841f51 104 va_start(arg, format);
bogdanm 13:0645d8841f51 105 fflush(_file);
bogdanm 13:0645d8841f51 106 int r = vfscanf(_file, format, arg);
bogdanm 13:0645d8841f51 107 va_end(arg);
bogdanm 13:0645d8841f51 108 return r;
bogdanm 13:0645d8841f51 109 }
bogdanm 13:0645d8841f51 110
bogdanm 13:0645d8841f51 111 } // namespace mbed