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/LocalFileSystem.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 "LocalFileSystem.h"
bogdanm 13:0645d8841f51 17
bogdanm 13:0645d8841f51 18 #if DEVICE_LOCALFILESYSTEM
bogdanm 13:0645d8841f51 19
bogdanm 13:0645d8841f51 20 #include "semihost_api.h"
bogdanm 13:0645d8841f51 21 #include <string.h>
bogdanm 13:0645d8841f51 22 #include <stdio.h>
bogdanm 13:0645d8841f51 23
bogdanm 13:0645d8841f51 24 namespace mbed {
bogdanm 13:0645d8841f51 25
bogdanm 13:0645d8841f51 26 /* Extension to FINFO type defined in RTL.h (in Keil RL) - adds 'create time'. */
bogdanm 13:0645d8841f51 27 typedef struct {
bogdanm 13:0645d8841f51 28 unsigned char hr; /* Hours [0..23] */
bogdanm 13:0645d8841f51 29 unsigned char min; /* Minutes [0..59] */
bogdanm 13:0645d8841f51 30 unsigned char sec; /* Seconds [0..59] */
bogdanm 13:0645d8841f51 31 unsigned char day; /* Day [1..31] */
bogdanm 13:0645d8841f51 32 unsigned char mon; /* Month [1..12] */
bogdanm 13:0645d8841f51 33 unsigned short year; /* Year [1980..2107] */
bogdanm 13:0645d8841f51 34 } FTIME;
bogdanm 13:0645d8841f51 35
bogdanm 13:0645d8841f51 36 typedef struct { /* File Search info record */
bogdanm 13:0645d8841f51 37 char name[32]; /* File name */
bogdanm 13:0645d8841f51 38 long size; /* File size in bytes */
bogdanm 13:0645d8841f51 39 int fileID; /* System File Identification */
bogdanm 13:0645d8841f51 40 FTIME create_time; /* Date & time file was created */
bogdanm 13:0645d8841f51 41 FTIME write_time; /* Date & time of last write */
bogdanm 13:0645d8841f51 42 } XFINFO;
bogdanm 13:0645d8841f51 43
bogdanm 13:0645d8841f51 44 #define RESERVED_FOR_USER_APPLICATIONS (0x100) /* 0x100 - 0x1ff */
bogdanm 13:0645d8841f51 45 #define USR_XFFIND (RESERVED_FOR_USER_APPLICATIONS + 0)
bogdanm 13:0645d8841f51 46
bogdanm 13:0645d8841f51 47 static int xffind (const char *pattern, XFINFO *info) {
bogdanm 13:0645d8841f51 48 unsigned param[4];
bogdanm 13:0645d8841f51 49
bogdanm 13:0645d8841f51 50 param[0] = (unsigned long)pattern;
bogdanm 13:0645d8841f51 51 param[1] = (unsigned long)strlen(pattern);
bogdanm 13:0645d8841f51 52 param[2] = (unsigned long)info;
bogdanm 13:0645d8841f51 53 param[3] = (unsigned long)sizeof(XFINFO);
bogdanm 13:0645d8841f51 54
bogdanm 13:0645d8841f51 55 return __semihost(USR_XFFIND, param);
bogdanm 13:0645d8841f51 56 }
bogdanm 13:0645d8841f51 57
bogdanm 13:0645d8841f51 58 #define OPEN_R 0
bogdanm 13:0645d8841f51 59 #define OPEN_B 1
bogdanm 13:0645d8841f51 60 #define OPEN_PLUS 2
bogdanm 13:0645d8841f51 61 #define OPEN_W 4
bogdanm 13:0645d8841f51 62 #define OPEN_A 8
bogdanm 13:0645d8841f51 63 #define OPEN_INVALID -1
bogdanm 13:0645d8841f51 64
bogdanm 13:0645d8841f51 65 int posix_to_semihost_open_flags(int flags) {
bogdanm 13:0645d8841f51 66 /* POSIX flags -> semihosting open mode */
bogdanm 13:0645d8841f51 67 int openmode;
bogdanm 13:0645d8841f51 68 if (flags & O_RDWR) {
bogdanm 13:0645d8841f51 69 /* a plus mode */
bogdanm 13:0645d8841f51 70 openmode = OPEN_PLUS;
bogdanm 13:0645d8841f51 71 if (flags & O_APPEND) {
bogdanm 13:0645d8841f51 72 openmode |= OPEN_A;
bogdanm 13:0645d8841f51 73 } else if (flags & O_TRUNC) {
bogdanm 13:0645d8841f51 74 openmode |= OPEN_W;
bogdanm 13:0645d8841f51 75 } else {
bogdanm 13:0645d8841f51 76 openmode |= OPEN_R;
bogdanm 13:0645d8841f51 77 }
bogdanm 13:0645d8841f51 78 } else if (flags & O_WRONLY) {
bogdanm 13:0645d8841f51 79 /* write or append */
bogdanm 13:0645d8841f51 80 if (flags & O_APPEND) {
bogdanm 13:0645d8841f51 81 openmode = OPEN_A;
bogdanm 13:0645d8841f51 82 } else {
bogdanm 13:0645d8841f51 83 openmode = OPEN_W;
bogdanm 13:0645d8841f51 84 }
bogdanm 13:0645d8841f51 85 } else if (flags == O_RDONLY) {
bogdanm 13:0645d8841f51 86 /* read mode */
bogdanm 13:0645d8841f51 87 openmode = OPEN_R;
bogdanm 13:0645d8841f51 88 } else {
bogdanm 13:0645d8841f51 89 /* invalid flags */
bogdanm 13:0645d8841f51 90 openmode = OPEN_INVALID;
bogdanm 13:0645d8841f51 91 }
bogdanm 13:0645d8841f51 92
bogdanm 13:0645d8841f51 93 return openmode;
bogdanm 13:0645d8841f51 94 }
bogdanm 13:0645d8841f51 95
bogdanm 13:0645d8841f51 96 FILEHANDLE local_file_open(const char* name, int flags) {
bogdanm 13:0645d8841f51 97 int openmode = posix_to_semihost_open_flags(flags);
bogdanm 13:0645d8841f51 98 if (openmode == OPEN_INVALID) {
bogdanm 13:0645d8841f51 99 return (FILEHANDLE)NULL;
bogdanm 13:0645d8841f51 100 }
bogdanm 13:0645d8841f51 101
bogdanm 13:0645d8841f51 102 FILEHANDLE fh = semihost_open(name, openmode);
bogdanm 13:0645d8841f51 103 if (fh == -1) {
bogdanm 13:0645d8841f51 104 return (FILEHANDLE)NULL;
bogdanm 13:0645d8841f51 105 }
bogdanm 13:0645d8841f51 106
bogdanm 13:0645d8841f51 107 return fh;
bogdanm 13:0645d8841f51 108 }
bogdanm 13:0645d8841f51 109
mbed_official 212:34d62c0b2af6 110 LocalFileHandle::LocalFileHandle(FILEHANDLE fh) : _fh(fh), pos(0) {
bogdanm 13:0645d8841f51 111 }
bogdanm 13:0645d8841f51 112
bogdanm 13:0645d8841f51 113 int LocalFileHandle::close() {
bogdanm 13:0645d8841f51 114 int retval = semihost_close(_fh);
bogdanm 13:0645d8841f51 115 delete this;
bogdanm 13:0645d8841f51 116 return retval;
bogdanm 13:0645d8841f51 117 }
bogdanm 13:0645d8841f51 118
bogdanm 13:0645d8841f51 119 ssize_t LocalFileHandle::write(const void *buffer, size_t length) {
bogdanm 13:0645d8841f51 120 ssize_t n = semihost_write(_fh, (const unsigned char*)buffer, length, 0); // number of characters not written
bogdanm 13:0645d8841f51 121 n = length - n; // number of characters written
bogdanm 13:0645d8841f51 122 pos += n;
bogdanm 13:0645d8841f51 123 return n;
bogdanm 13:0645d8841f51 124 }
bogdanm 13:0645d8841f51 125
bogdanm 13:0645d8841f51 126 ssize_t LocalFileHandle::read(void *buffer, size_t length) {
bogdanm 13:0645d8841f51 127 ssize_t n = semihost_read(_fh, (unsigned char*)buffer, length, 0); // number of characters not read
bogdanm 13:0645d8841f51 128 n = length - n; // number of characters read
bogdanm 13:0645d8841f51 129 pos += n;
bogdanm 13:0645d8841f51 130 return n;
bogdanm 13:0645d8841f51 131 }
bogdanm 13:0645d8841f51 132
bogdanm 13:0645d8841f51 133 int LocalFileHandle::isatty() {
bogdanm 13:0645d8841f51 134 return semihost_istty(_fh);
bogdanm 13:0645d8841f51 135 }
bogdanm 13:0645d8841f51 136
bogdanm 13:0645d8841f51 137 off_t LocalFileHandle::lseek(off_t position, int whence) {
bogdanm 13:0645d8841f51 138 if (whence == SEEK_CUR) {
bogdanm 13:0645d8841f51 139 position += pos;
bogdanm 13:0645d8841f51 140 } else if (whence == SEEK_END) {
bogdanm 13:0645d8841f51 141 position += semihost_flen(_fh);
bogdanm 13:0645d8841f51 142 } /* otherwise SEEK_SET, so position is fine */
bogdanm 13:0645d8841f51 143
bogdanm 13:0645d8841f51 144 /* Always seems to return -1, so just ignore for now. */
bogdanm 13:0645d8841f51 145 semihost_seek(_fh, position);
bogdanm 13:0645d8841f51 146 pos = position;
bogdanm 13:0645d8841f51 147 return position;
bogdanm 13:0645d8841f51 148 }
bogdanm 13:0645d8841f51 149
bogdanm 13:0645d8841f51 150 int LocalFileHandle::fsync() {
bogdanm 13:0645d8841f51 151 return semihost_ensure(_fh);
bogdanm 13:0645d8841f51 152 }
bogdanm 13:0645d8841f51 153
bogdanm 13:0645d8841f51 154 off_t LocalFileHandle::flen() {
bogdanm 13:0645d8841f51 155 return semihost_flen(_fh);
bogdanm 13:0645d8841f51 156 }
bogdanm 13:0645d8841f51 157
bogdanm 13:0645d8841f51 158 class LocalDirHandle : public DirHandle {
bogdanm 13:0645d8841f51 159
bogdanm 13:0645d8841f51 160 public:
bogdanm 13:0645d8841f51 161 struct dirent cur_entry;
bogdanm 13:0645d8841f51 162 XFINFO info;
bogdanm 13:0645d8841f51 163
mbed_official 212:34d62c0b2af6 164 LocalDirHandle() : cur_entry(), info() {
bogdanm 13:0645d8841f51 165 }
bogdanm 13:0645d8841f51 166
bogdanm 13:0645d8841f51 167 virtual int closedir() {
bogdanm 13:0645d8841f51 168 delete this;
bogdanm 13:0645d8841f51 169 return 0;
bogdanm 13:0645d8841f51 170 }
bogdanm 13:0645d8841f51 171
bogdanm 13:0645d8841f51 172 virtual struct dirent *readdir() {
bogdanm 13:0645d8841f51 173 if (xffind("*", &info)!=0) {
bogdanm 13:0645d8841f51 174 return NULL;
bogdanm 13:0645d8841f51 175 }
bogdanm 13:0645d8841f51 176 memcpy(cur_entry.d_name, info.name, sizeof(info.name));
bogdanm 13:0645d8841f51 177 return &cur_entry;
bogdanm 13:0645d8841f51 178 }
bogdanm 13:0645d8841f51 179
bogdanm 13:0645d8841f51 180 virtual void rewinddir() {
bogdanm 13:0645d8841f51 181 info.fileID = 0;
bogdanm 13:0645d8841f51 182 }
bogdanm 13:0645d8841f51 183
bogdanm 13:0645d8841f51 184 virtual off_t telldir() {
bogdanm 13:0645d8841f51 185 return info.fileID;
bogdanm 13:0645d8841f51 186 }
bogdanm 13:0645d8841f51 187
bogdanm 13:0645d8841f51 188 virtual void seekdir(off_t offset) {
bogdanm 13:0645d8841f51 189 info.fileID = offset;
bogdanm 13:0645d8841f51 190 }
bogdanm 13:0645d8841f51 191 };
bogdanm 13:0645d8841f51 192
bogdanm 13:0645d8841f51 193 FileHandle *LocalFileSystem::open(const char* name, int flags) {
bogdanm 13:0645d8841f51 194 /* reject filenames with / in them */
bogdanm 13:0645d8841f51 195 for (const char *tmp = name; *tmp; tmp++) {
bogdanm 13:0645d8841f51 196 if (*tmp == '/') {
bogdanm 13:0645d8841f51 197 return NULL;
bogdanm 13:0645d8841f51 198 }
bogdanm 13:0645d8841f51 199 }
bogdanm 13:0645d8841f51 200
bogdanm 13:0645d8841f51 201 int openmode = posix_to_semihost_open_flags(flags);
bogdanm 13:0645d8841f51 202 if (openmode == OPEN_INVALID) {
bogdanm 13:0645d8841f51 203 return NULL;
bogdanm 13:0645d8841f51 204 }
bogdanm 13:0645d8841f51 205
bogdanm 13:0645d8841f51 206 FILEHANDLE fh = semihost_open(name, openmode);
bogdanm 13:0645d8841f51 207 if (fh == -1) {
bogdanm 13:0645d8841f51 208 return NULL;
bogdanm 13:0645d8841f51 209 }
bogdanm 13:0645d8841f51 210 return new LocalFileHandle(fh);
bogdanm 13:0645d8841f51 211 }
bogdanm 13:0645d8841f51 212
bogdanm 13:0645d8841f51 213 int LocalFileSystem::remove(const char *filename) {
bogdanm 13:0645d8841f51 214 return semihost_remove(filename);
bogdanm 13:0645d8841f51 215 }
bogdanm 13:0645d8841f51 216
bogdanm 13:0645d8841f51 217 DirHandle *LocalFileSystem::opendir(const char *name) {
bogdanm 13:0645d8841f51 218 return new LocalDirHandle();
bogdanm 13:0645d8841f51 219 }
bogdanm 13:0645d8841f51 220
bogdanm 13:0645d8841f51 221 } // namespace mbed
bogdanm 13:0645d8841f51 222
bogdanm 13:0645d8841f51 223 #endif