| 1 | /** |
| 2 | * @file |
| 3 | * lwIP Operating System abstraction |
| 4 | * |
| 5 | */ |
| 6 | |
| 7 | /* |
| 8 | * Copyright (c) 2001-2004 Swedish Institute of Computer Science. |
| 9 | * All rights reserved. |
| 10 | * |
| 11 | * Redistribution and use in source and binary forms, with or without modification, |
| 12 | * are permitted provided that the following conditions are met: |
| 13 | * |
| 14 | * 1. Redistributions of source code must retain the above copyright notice, |
| 15 | * this list of conditions and the following disclaimer. |
| 16 | * 2. Redistributions in binary form must reproduce the above copyright notice, |
| 17 | * this list of conditions and the following disclaimer in the documentation |
| 18 | * and/or other materials provided with the distribution. |
| 19 | * 3. The name of the author may not be used to endorse or promote products |
| 20 | * derived from this software without specific prior written permission. |
| 21 | * |
| 22 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED |
| 23 | * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF |
| 24 | * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT |
| 25 | * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
| 26 | * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT |
| 27 | * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| 28 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| 29 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING |
| 30 | * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY |
| 31 | * OF SUCH DAMAGE. |
| 32 | * |
| 33 | * This file is part of the lwIP TCP/IP stack. |
| 34 | * |
| 35 | * Author: Adam Dunkels <adam@sics.se> |
| 36 | * |
| 37 | */ |
| 38 | |
| 39 | #include "lwip/opt.h" |
| 40 | |
| 41 | #if (NO_SYS == 0) /* don't build if not configured for use in lwipopts.h */ |
| 42 | |
| 43 | #include "lwip/sys.h" |
| 44 | #include "lwip/def.h" |
| 45 | #include "lwip/memp.h" |
| 46 | #include "lwip/tcpip.h" |
| 47 | |
| 48 | /** |
| 49 | * Struct used for sys_sem_wait_timeout() to tell wether the time |
| 50 | * has run out or the semaphore has really become available. |
| 51 | */ |
| 52 | struct sswt_cb |
| 53 | { |
| 54 | s16_t timeflag; |
| 55 | sys_sem_t *psem; |
| 56 | }; |
| 57 | |
| 58 | /** |
| 59 | * Wait (forever) for a message to arrive in an mbox. |
| 60 | * While waiting, timeouts (for this thread) are processed. |
| 61 | * |
| 62 | * @param mbox the mbox to fetch the message from |
| 63 | * @param msg the place to store the message |
| 64 | */ |
| 65 | void |
| 66 | sys_mbox_fetch(sys_mbox_t mbox, void **msg) |
| 67 | { |
| 68 | u32_t time; |
| 69 | struct sys_timeouts *timeouts; |
| 70 | struct sys_timeo *tmptimeout; |
| 71 | sys_timeout_handler h; |
| 72 | void *arg; |
| 73 | |
| 74 | again: |
| 75 | timeouts = sys_arch_timeouts(); |
| 76 | |
| 77 | if (!timeouts || !timeouts->next) { |
| 78 | UNLOCK_TCPIP_CORE(); |
| 79 | time = sys_arch_mbox_fetch(mbox, msg, 0); |
| 80 | LOCK_TCPIP_CORE(); |
| 81 | } else { |
| 82 | if (timeouts->next->time > 0) { |
| 83 | UNLOCK_TCPIP_CORE(); |
| 84 | time = sys_arch_mbox_fetch(mbox, msg, timeouts->next->time); |
| 85 | LOCK_TCPIP_CORE(); |
| 86 | } else { |
| 87 | time = SYS_ARCH_TIMEOUT; |
| 88 | } |
| 89 | |
| 90 | if (time == SYS_ARCH_TIMEOUT) { |
| 91 | /* If time == SYS_ARCH_TIMEOUT, a timeout occured before a message |
| 92 | could be fetched. We should now call the timeout handler and |
| 93 | deallocate the memory allocated for the timeout. */ |
| 94 | tmptimeout = timeouts->next; |
| 95 | timeouts->next = tmptimeout->next; |
| 96 | h = tmptimeout->h; |
| 97 | arg = tmptimeout->arg; |
| 98 | memp_free(MEMP_SYS_TIMEOUT, tmptimeout); |
| 99 | if (h != NULL) { |
| 100 | LWIP_DEBUGF(SYS_DEBUG, ("smf calling h=%p(%p)\n", (void*)&h, arg)); |
| 101 | h(arg); |
| 102 | } |
| 103 | |
| 104 | /* We try again to fetch a message from the mbox. */ |
| 105 | goto again; |
| 106 | } else { |
| 107 | /* If time != SYS_ARCH_TIMEOUT, a message was received before the timeout |
| 108 | occured. The time variable is set to the number of |
| 109 | milliseconds we waited for the message. */ |
| 110 | if (time < timeouts->next->time) { |
| 111 | timeouts->next->time -= time; |
| 112 | } else { |
| 113 | timeouts->next->time = 0; |
| 114 | } |
| 115 | } |
| 116 | } |
| 117 | } |
| 118 | |
| 119 | /** |
| 120 | * Wait (forever) for a semaphore to become available. |
| 121 | * While waiting, timeouts (for this thread) are processed. |
| 122 | * |
| 123 | * @param sem semaphore to wait for |
| 124 | */ |
| 125 | void |
| 126 | sys_sem_wait(sys_sem_t sem) |
| 127 | { |
| 128 | u32_t time; |
| 129 | struct sys_timeouts *timeouts; |
| 130 | struct sys_timeo *tmptimeout; |
| 131 | sys_timeout_handler h; |
| 132 | void *arg; |
| 133 | |
| 134 | again: |
| 135 | |
| 136 | timeouts = sys_arch_timeouts(); |
| 137 | |
| 138 | if (!timeouts || !timeouts->next) { |
| 139 | sys_arch_sem_wait(sem, 0); |
| 140 | } else { |
| 141 | if (timeouts->next->time > 0) { |
| 142 | time = sys_arch_sem_wait(sem, timeouts->next->time); |
| 143 | } else { |
| 144 | time = SYS_ARCH_TIMEOUT; |
| 145 | } |
| 146 | |
| 147 | if (time == SYS_ARCH_TIMEOUT) { |
| 148 | /* If time == SYS_ARCH_TIMEOUT, a timeout occured before a message |
| 149 | could be fetched. We should now call the timeout handler and |
| 150 | deallocate the memory allocated for the timeout. */ |
| 151 | tmptimeout = timeouts->next; |
| 152 | timeouts->next = tmptimeout->next; |
| 153 | h = tmptimeout->h; |
| 154 | arg = tmptimeout->arg; |
| 155 | memp_free(MEMP_SYS_TIMEOUT, tmptimeout); |
| 156 | if (h != NULL) { |
| 157 | LWIP_DEBUGF(SYS_DEBUG, ("ssw h=%p(%p)\n", (void*)&h, (void *)arg)); |
| 158 | h(arg); |
| 159 | } |
| 160 | |
| 161 | /* We try again to fetch a message from the mbox. */ |
| 162 | goto again; |
| 163 | } else { |
| 164 | /* If time != SYS_ARCH_TIMEOUT, a message was received before the timeout |
| 165 | occured. The time variable is set to the number of |
| 166 | milliseconds we waited for the message. */ |
| 167 | if (time < timeouts->next->time) { |
| 168 | timeouts->next->time -= time; |
| 169 | } else { |
| 170 | timeouts->next->time = 0; |
| 171 | } |
| 172 | } |
| 173 | } |
| 174 | } |
| 175 | |
| 176 | /** |
| 177 | * Create a one-shot timer (aka timeout). Timeouts are processed in the |
| 178 | * following cases: |
| 179 | * - while waiting for a message using sys_mbox_fetch() |
| 180 | * - while waiting for a semaphore using sys_sem_wait() or sys_sem_wait_timeout() |
| 181 | * - while sleeping using the inbuilt sys_msleep() |
| 182 | * |
| 183 | * @param msecs time in milliseconds after that the timer should expire |
| 184 | * @param h callback function to call when msecs have elapsed |
| 185 | * @param arg argument to pass to the callback function |
| 186 | */ |
| 187 | void |
| 188 | sys_timeout(u32_t msecs, sys_timeout_handler h, void *arg) |
| 189 | { |
| 190 | struct sys_timeouts *timeouts; |
| 191 | struct sys_timeo *timeout, *t; |
| 192 | |
| 193 | timeout = memp_malloc(MEMP_SYS_TIMEOUT); |
| 194 | if (timeout == NULL) { |
| 195 | LWIP_ASSERT("sys_timeout: timeout != NULL", timeout != NULL); |
| 196 | return; |
| 197 | } |
| 198 | timeout->next = NULL; |
| 199 | timeout->h = h; |
| 200 | timeout->arg = arg; |
| 201 | timeout->time = msecs; |
| 202 | |
| 203 | timeouts = sys_arch_timeouts(); |
| 204 | |
| 205 | LWIP_DEBUGF(SYS_DEBUG, ("sys_timeout: %p msecs=%"U32_F" h=%p arg=%p\n", |
| 206 | (void *)timeout, msecs, (void*)&h, (void *)arg)); |
| 207 | |
| 208 | if (timeouts == NULL) { |
| 209 | LWIP_ASSERT("sys_timeout: timeouts != NULL", timeouts != NULL); |
| 210 | return; |
| 211 | } |
| 212 | |
| 213 | if (timeouts->next == NULL) { |
| 214 | timeouts->next = timeout; |
| 215 | return; |
| 216 | } |
| 217 | |
| 218 | if (timeouts->next->time > msecs) { |
| 219 | timeouts->next->time -= msecs; |
| 220 | timeout->next = timeouts->next; |
| 221 | timeouts->next = timeout; |
| 222 | } else { |
| 223 | for(t = timeouts->next; t != NULL; t = t->next) { |
| 224 | timeout->time -= t->time; |
| 225 | if (t->next == NULL || t->next->time > timeout->time) { |
| 226 | if (t->next != NULL) { |
| 227 | t->next->time -= timeout->time; |
| 228 | } |
| 229 | timeout->next = t->next; |
| 230 | t->next = timeout; |
| 231 | break; |
| 232 | } |
| 233 | } |
| 234 | } |
| 235 | } |
| 236 | |
| 237 | /** |
| 238 | * Go through timeout list (for this task only) and remove the first matching |
| 239 | * entry, even though the timeout has not triggered yet. |
| 240 | * |
| 241 | * @note This function only works as expected if there is only one timeout |
| 242 | * calling 'h' in the list of timeouts. |
| 243 | * |
| 244 | * @param h callback function that would be called by the timeout |
| 245 | * @param arg callback argument that would be passed to h |
| 246 | */ |
| 247 | void |
| 248 | sys_untimeout(sys_timeout_handler h, void *arg) |
| 249 | { |
| 250 | struct sys_timeouts *timeouts; |
| 251 | struct sys_timeo *prev_t, *t; |
| 252 | |
| 253 | timeouts = sys_arch_timeouts(); |
| 254 | |
| 255 | if (timeouts == NULL) { |
| 256 | LWIP_ASSERT("sys_untimeout: timeouts != NULL", timeouts != NULL); |
| 257 | return; |
| 258 | } |
| 259 | if (timeouts->next == NULL) { |
| 260 | return; |
| 261 | } |
| 262 | |
| 263 | for (t = timeouts->next, prev_t = NULL; t != NULL; prev_t = t, t = t->next) { |
| 264 | if ((t->h == h) && (t->arg == arg)) { |
| 265 | /* We have a match */ |
| 266 | /* Unlink from previous in list */ |
| 267 | if (prev_t == NULL) |
| 268 | timeouts->next = t->next; |
| 269 | else |
| 270 | prev_t->next = t->next; |
| 271 | /* If not the last one, add time of this one back to next */ |
| 272 | if (t->next != NULL) |
| 273 | t->next->time += t->time; |
| 274 | memp_free(MEMP_SYS_TIMEOUT, t); |
| 275 | return; |
| 276 | } |
| 277 | } |
| 278 | return; |
| 279 | } |
| 280 | |
| 281 | /** |
| 282 | * Timeout handler function for sys_sem_wait_timeout() |
| 283 | * |
| 284 | * @param arg struct sswt_cb* used to signal a semaphore and end waiting. |
| 285 | */ |
| 286 | static void |
| 287 | sswt_handler(void *arg) |
| 288 | { |
| 289 | struct sswt_cb *sswt_cb = (struct sswt_cb *) arg; |
| 290 | |
| 291 | /* Timeout. Set flag to TRUE and signal semaphore */ |
| 292 | sswt_cb->timeflag = 1; |
| 293 | sys_sem_signal(*(sswt_cb->psem)); |
| 294 | } |
| 295 | |
| 296 | /** |
| 297 | * Wait for a semaphore with timeout (specified in ms) |
| 298 | * |
| 299 | * @param sem semaphore to wait |
| 300 | * @param timeout timeout in ms (0: wait forever) |
| 301 | * @return 0 on timeout, 1 otherwise |
| 302 | */ |
| 303 | int |
| 304 | sys_sem_wait_timeout(sys_sem_t sem, u32_t timeout) |
| 305 | { |
| 306 | struct sswt_cb sswt_cb; |
| 307 | |
| 308 | sswt_cb.psem = &sem; |
| 309 | sswt_cb.timeflag = 0; |
| 310 | |
| 311 | /* If timeout is zero, then just wait forever */ |
| 312 | if (timeout > 0) { |
| 313 | /* Create a timer and pass it the address of our flag */ |
| 314 | sys_timeout(timeout, sswt_handler, &sswt_cb); |
| 315 | } |
| 316 | sys_sem_wait(sem); |
| 317 | /* Was it a timeout? */ |
| 318 | if (sswt_cb.timeflag) { |
| 319 | /* timeout */ |
| 320 | return 0; |
| 321 | } else { |
| 322 | /* Not a timeout. Remove timeout entry */ |
| 323 | sys_untimeout(sswt_handler, &sswt_cb); |
| 324 | return 1; |
| 325 | } |
| 326 | } |
| 327 | |
| 328 | /** |
| 329 | * Sleep for some ms. Timeouts are processed while sleeping. |
| 330 | * |
| 331 | * @param ms number of milliseconds to sleep |
| 332 | */ |
| 333 | void |
| 334 | sys_msleep(u32_t ms) |
| 335 | { |
| 336 | sys_sem_t delaysem = sys_sem_new(0); |
| 337 | |
| 338 | sys_sem_wait_timeout(delaysem, ms); |
| 339 | |
| 340 | sys_sem_free(delaysem); |
| 341 | } |
| 342 | |
| 343 | |
| 344 | #endif /* NO_SYS */ |