1/**
2 * @file
3 * OS abstraction layer
4 */
5
6/*
7 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
8 * All rights reserved.
9 *
10 * Redistribution and use in source and binary forms, with or without modification,
11 * are permitted provided that the following conditions are met:
12 *
13 * 1. Redistributions of source code must retain the above copyright notice,
14 *    this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright notice,
16 *    this list of conditions and the following disclaimer in the documentation
17 *    and/or other materials provided with the distribution.
18 * 3. The name of the author may not be used to endorse or promote products
19 *    derived from this software without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
22 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
23 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
24 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
25 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
26 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
29 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
30 * OF SUCH DAMAGE.
31 *
32 * This file is part of the lwIP TCP/IP stack.
33 *
34 * Author: Adam Dunkels <adam@sics.se>
35 */
36
37#ifndef LWIP_HDR_SYS_H
38#define LWIP_HDR_SYS_H
39
40#include "lwip/opt.h"
41
42#ifdef __cplusplus
43extern "C" {
44#endif
45
46#if NO_SYS
47
48/* For a totally minimal and standalone system, we provide null
49   definitions of the sys_ functions. */
50typedef u8_t sys_sem_t;
51typedef u8_t sys_mutex_t;
52typedef u8_t sys_mbox_t;
53
54#define sys_sem_new(s, c) ERR_OK
55#define sys_sem_signal(s)
56#define sys_sem_wait(s)
57#define sys_arch_sem_wait(s,t)
58#define sys_sem_free(s)
59#define sys_sem_valid(s) 0
60#define sys_sem_valid_val(s) 0
61#define sys_sem_set_invalid(s)
62#define sys_sem_set_invalid_val(s)
63#define sys_mutex_new(mu) ERR_OK
64#define sys_mutex_lock(mu)
65#define sys_mutex_unlock(mu)
66#define sys_mutex_free(mu)
67#define sys_mutex_valid(mu) 0
68#define sys_mutex_set_invalid(mu)
69#define sys_mbox_new(m, s) ERR_OK
70#define sys_mbox_fetch(m,d)
71#define sys_mbox_tryfetch(m,d)
72#define sys_mbox_post(m,d)
73#define sys_mbox_trypost(m,d)
74#define sys_mbox_free(m)
75#define sys_mbox_valid(m)
76#define sys_mbox_valid_val(m)
77#define sys_mbox_set_invalid(m)
78#define sys_mbox_set_invalid_val(m)
79
80#define sys_thread_new(n,t,a,s,p)
81
82#define sys_msleep(t)
83
84#else /* NO_SYS */
85
86/** Return code for timeouts from sys_arch_mbox_fetch and sys_arch_sem_wait */
87#define SYS_ARCH_TIMEOUT 0xffffffffUL
88
89/** sys_mbox_tryfetch() returns SYS_MBOX_EMPTY if appropriate.
90 * For now we use the same magic value, but we allow this to change in future.
91 */
92#define SYS_MBOX_EMPTY SYS_ARCH_TIMEOUT
93
94#include "lwip/err.h"
95#include "arch/sys_arch.h"
96
97/** Function prototype for thread functions */
98typedef void (*lwip_thread_fn)(void *arg);
99
100/* Function prototypes for functions to be implemented by platform ports
101   (in sys_arch.c) */
102
103/* Mutex functions: */
104
105/** Define LWIP_COMPAT_MUTEX if the port has no mutexes and binary semaphores
106    should be used instead */
107#ifndef LWIP_COMPAT_MUTEX
108#define LWIP_COMPAT_MUTEX 0
109#endif
110
111#if LWIP_COMPAT_MUTEX
112/* for old ports that don't have mutexes: define them to binary semaphores */
113#define sys_mutex_t                   sys_sem_t
114#define sys_mutex_new(mutex)          sys_sem_new(mutex, 1)
115#define sys_mutex_lock(mutex)         sys_sem_wait(mutex)
116#define sys_mutex_unlock(mutex)       sys_sem_signal(mutex)
117#define sys_mutex_free(mutex)         sys_sem_free(mutex)
118#define sys_mutex_valid(mutex)        sys_sem_valid(mutex)
119#define sys_mutex_set_invalid(mutex)  sys_sem_set_invalid(mutex)
120
121#else /* LWIP_COMPAT_MUTEX */
122
123/**
124 * @ingroup sys_mutex
125 * Create a new mutex.
126 * Note that mutexes are expected to not be taken recursively by the lwIP code,
127 * so both implementation types (recursive or non-recursive) should work.
128 * @param mutex pointer to the mutex to create
129 * @return ERR_OK if successful, another err_t otherwise
130 */
131err_t sys_mutex_new(sys_mutex_t *mutex);
132/**
133 * @ingroup sys_mutex
134 * Lock a mutex
135 * @param mutex the mutex to lock
136 */
137void sys_mutex_lock(sys_mutex_t *mutex);
138/**
139 * @ingroup sys_mutex
140 * Unlock a mutex
141 * @param mutex the mutex to unlock
142 */
143void sys_mutex_unlock(sys_mutex_t *mutex);
144/**
145 * @ingroup sys_mutex
146 * Delete a semaphore
147 * @param mutex the mutex to delete
148 */
149void sys_mutex_free(sys_mutex_t *mutex);
150#ifndef sys_mutex_valid
151/**
152 * @ingroup sys_mutex
153 * Check if a mutex is valid/allocated: return 1 for valid, 0 for invalid
154 */
155int sys_mutex_valid(sys_mutex_t *mutex);
156#endif
157#ifndef sys_mutex_set_invalid
158/**
159 * @ingroup sys_mutex
160 * Set a mutex invalid so that sys_mutex_valid returns 0
161 */
162void sys_mutex_set_invalid(sys_mutex_t *mutex);
163#endif
164#endif /* LWIP_COMPAT_MUTEX */
165
166/* Semaphore functions: */
167
168/**
169 * @ingroup sys_sem
170 * Create a new semaphore
171 * @param sem pointer to the semaphore to create
172 * @param count initial count of the semaphore
173 * @return ERR_OK if successful, another err_t otherwise
174 */
175err_t sys_sem_new(sys_sem_t *sem, u8_t count);
176/**
177 * @ingroup sys_sem
178 * Signals a semaphore
179 * @param sem the semaphore to signal
180 */
181void sys_sem_signal(sys_sem_t *sem);
182/**
183 * @ingroup sys_sem
184 * Wait for a semaphore for the specified timeout
185 * @param sem the semaphore to wait for
186 * @param timeout timeout in milliseconds to wait (0 = wait forever)
187 * @return time (in milliseconds) waited for the semaphore
188 *         or SYS_ARCH_TIMEOUT on timeout
189 */
190u32_t sys_arch_sem_wait(sys_sem_t *sem, u32_t timeout);
191/**
192 * @ingroup sys_sem
193 * Delete a semaphore
194 * @param sem semaphore to delete
195 */
196void sys_sem_free(sys_sem_t *sem);
197/** Wait for a semaphore - forever/no timeout */
198#define sys_sem_wait(sem)                  sys_arch_sem_wait(sem, 0)
199#ifndef sys_sem_valid
200/**
201 * @ingroup sys_sem
202 * Check if a semaphore is valid/allocated: return 1 for valid, 0 for invalid
203 */
204int sys_sem_valid(sys_sem_t *sem);
205#endif
206#ifndef sys_sem_set_invalid
207/**
208 * @ingroup sys_sem
209 * Set a semaphore invalid so that sys_sem_valid returns 0
210 */
211void sys_sem_set_invalid(sys_sem_t *sem);
212#endif
213#ifndef sys_sem_valid_val
214/**
215 * Same as sys_sem_valid() but taking a value, not a pointer
216 */
217#define sys_sem_valid_val(sem)       sys_sem_valid(&(sem))
218#endif
219#ifndef sys_sem_set_invalid_val
220/**
221 * Same as sys_sem_set_invalid() but taking a value, not a pointer
222 */
223#define sys_sem_set_invalid_val(sem) sys_sem_set_invalid(&(sem))
224#endif
225
226#ifndef sys_msleep
227/**
228 * @ingroup sys_misc
229 * Sleep for specified number of ms
230 */
231void sys_msleep(u32_t ms); /* only has a (close to) 1 ms resolution. */
232#endif
233
234/* Mailbox functions. */
235
236/**
237 * @ingroup sys_mbox
238 * Create a new mbox of specified size
239 * @param mbox pointer to the mbox to create
240 * @param size (minimum) number of messages in this mbox
241 * @return ERR_OK if successful, another err_t otherwise
242 */
243err_t sys_mbox_new(sys_mbox_t *mbox, int size);
244/**
245 * @ingroup sys_mbox
246 * Post a message to an mbox - may not fail
247 * -> blocks if full, only used from tasks not from ISR
248 * @param mbox mbox to posts the message
249 * @param msg message to post (ATTENTION: can be NULL)
250 */
251void sys_mbox_post(sys_mbox_t *mbox, void *msg);
252/**
253 * @ingroup sys_mbox
254 * Try to post a message to an mbox - may fail if full or ISR
255 * @param mbox mbox to posts the message
256 * @param msg message to post (ATTENTION: can be NULL)
257 */
258err_t sys_mbox_trypost(sys_mbox_t *mbox, void *msg);
259/**
260 * @ingroup sys_mbox
261 * Wait for a new message to arrive in the mbox
262 * @param mbox mbox to get a message from
263 * @param msg pointer where the message is stored
264 * @param timeout maximum time (in milliseconds) to wait for a message (0 = wait forever)
265 * @return time (in milliseconds) waited for a message, may be 0 if not waited
266           or SYS_ARCH_TIMEOUT on timeout
267 *         The returned time has to be accurate to prevent timer jitter!
268 */
269u32_t sys_arch_mbox_fetch(sys_mbox_t *mbox, void **msg, u32_t timeout);
270/* Allow port to override with a macro, e.g. special timeout for sys_arch_mbox_fetch() */
271#ifndef sys_arch_mbox_tryfetch
272/**
273 * @ingroup sys_mbox
274 * Wait for a new message to arrive in the mbox
275 * @param mbox mbox to get a message from
276 * @param msg pointer where the message is stored
277 * @return 0 (milliseconds) if a message has been received
278 *         or SYS_MBOX_EMPTY if the mailbox is empty
279 */
280u32_t sys_arch_mbox_tryfetch(sys_mbox_t *mbox, void **msg);
281#endif
282/**
283 * For now, we map straight to sys_arch implementation.
284 */
285#define sys_mbox_tryfetch(mbox, msg) sys_arch_mbox_tryfetch(mbox, msg)
286/**
287 * @ingroup sys_mbox
288 * Delete an mbox
289 * @param mbox mbox to delete
290 */
291void sys_mbox_free(sys_mbox_t *mbox);
292#define sys_mbox_fetch(mbox, msg) sys_arch_mbox_fetch(mbox, msg, 0)
293#ifndef sys_mbox_valid
294/**
295 * @ingroup sys_mbox
296 * Check if an mbox is valid/allocated: return 1 for valid, 0 for invalid
297 */
298int sys_mbox_valid(sys_mbox_t *mbox);
299#endif
300#ifndef sys_mbox_set_invalid
301/**
302 * @ingroup sys_mbox
303 * Set an mbox invalid so that sys_mbox_valid returns 0
304 */
305void sys_mbox_set_invalid(sys_mbox_t *mbox);
306#endif
307#ifndef sys_mbox_valid_val
308/**
309 * Same as sys_mbox_valid() but taking a value, not a pointer
310 */
311#define sys_mbox_valid_val(mbox)       sys_mbox_valid(&(mbox))
312#endif
313#ifndef sys_mbox_set_invalid_val
314/**
315 * Same as sys_mbox_set_invalid() but taking a value, not a pointer
316 */
317#define sys_mbox_set_invalid_val(mbox) sys_mbox_set_invalid(&(mbox))
318#endif
319
320
321/**
322 * @ingroup sys_misc
323 * The only thread function:
324 * Creates a new thread
325 * ATTENTION: although this function returns a value, it MUST NOT FAIL (ports have to assert this!)
326 * @param name human-readable name for the thread (used for debugging purposes)
327 * @param thread thread-function
328 * @param arg parameter passed to 'thread'
329 * @param stacksize stack size in bytes for the new thread (may be ignored by ports)
330 * @param prio priority of the new thread (may be ignored by ports) */
331sys_thread_t sys_thread_new(const char *name, lwip_thread_fn thread, void *arg, int stacksize, int prio);
332
333#endif /* NO_SYS */
334
335/* sys_init() must be called before anything else. */
336void sys_init(void);
337
338#ifndef sys_jiffies
339/**
340 * Ticks/jiffies since power up.
341 */
342u32_t sys_jiffies(void);
343#endif
344
345/**
346 * @ingroup sys_time
347 * Returns the current time in milliseconds,
348 * may be the same as sys_jiffies or at least based on it.
349 */
350u32_t sys_now(void);
351
352/* Critical Region Protection */
353/* These functions must be implemented in the sys_arch.c file.
354   In some implementations they can provide a more light-weight protection
355   mechanism than using semaphores. Otherwise semaphores can be used for
356   implementation */
357#ifndef SYS_ARCH_PROTECT
358/** SYS_LIGHTWEIGHT_PROT
359 * define SYS_LIGHTWEIGHT_PROT in lwipopts.h if you want inter-task protection
360 * for certain critical regions during buffer allocation, deallocation and memory
361 * allocation and deallocation.
362 */
363#if SYS_LIGHTWEIGHT_PROT
364
365/**
366 * @ingroup sys_prot
367 * SYS_ARCH_DECL_PROTECT
368 * declare a protection variable. This macro will default to defining a variable of
369 * type sys_prot_t. If a particular port needs a different implementation, then
370 * this macro may be defined in sys_arch.h.
371 */
372#define SYS_ARCH_DECL_PROTECT(lev) sys_prot_t lev
373/**
374 * @ingroup sys_prot
375 * SYS_ARCH_PROTECT
376 * Perform a "fast" protect. This could be implemented by
377 * disabling interrupts for an embedded system or by using a semaphore or
378 * mutex. The implementation should allow calling SYS_ARCH_PROTECT when
379 * already protected. The old protection level is returned in the variable
380 * "lev". This macro will default to calling the sys_arch_protect() function
381 * which should be implemented in sys_arch.c. If a particular port needs a
382 * different implementation, then this macro may be defined in sys_arch.h
383 */
384#define SYS_ARCH_PROTECT(lev) lev = sys_arch_protect()
385/**
386 * @ingroup sys_prot
387 * SYS_ARCH_UNPROTECT
388 * Perform a "fast" set of the protection level to "lev". This could be
389 * implemented by setting the interrupt level to "lev" within the MACRO or by
390 * using a semaphore or mutex.  This macro will default to calling the
391 * sys_arch_unprotect() function which should be implemented in
392 * sys_arch.c. If a particular port needs a different implementation, then
393 * this macro may be defined in sys_arch.h
394 */
395#define SYS_ARCH_UNPROTECT(lev) sys_arch_unprotect(lev)
396sys_prot_t sys_arch_protect(void);
397void sys_arch_unprotect(sys_prot_t pval);
398
399#else
400
401#define SYS_ARCH_DECL_PROTECT(lev)
402#define SYS_ARCH_PROTECT(lev)
403#define SYS_ARCH_UNPROTECT(lev)
404
405#endif /* SYS_LIGHTWEIGHT_PROT */
406
407#endif /* SYS_ARCH_PROTECT */
408
409/*
410 * Macros to set/get and increase/decrease variables in a thread-safe way.
411 * Use these for accessing variable that are used from more than one thread.
412 */
413
414#ifndef SYS_ARCH_INC
415#define SYS_ARCH_INC(var, val) do { \
416                                SYS_ARCH_DECL_PROTECT(old_level); \
417                                SYS_ARCH_PROTECT(old_level); \
418                                var += val; \
419                                SYS_ARCH_UNPROTECT(old_level); \
420                              } while(0)
421#endif /* SYS_ARCH_INC */
422
423#ifndef SYS_ARCH_DEC
424#define SYS_ARCH_DEC(var, val) do { \
425                                SYS_ARCH_DECL_PROTECT(old_level); \
426                                SYS_ARCH_PROTECT(old_level); \
427                                var -= val; \
428                                SYS_ARCH_UNPROTECT(old_level); \
429                              } while(0)
430#endif /* SYS_ARCH_DEC */
431
432#ifndef SYS_ARCH_GET
433#define SYS_ARCH_GET(var, ret) do { \
434                                SYS_ARCH_DECL_PROTECT(old_level); \
435                                SYS_ARCH_PROTECT(old_level); \
436                                ret = var; \
437                                SYS_ARCH_UNPROTECT(old_level); \
438                              } while(0)
439#endif /* SYS_ARCH_GET */
440
441#ifndef SYS_ARCH_SET
442#define SYS_ARCH_SET(var, val) do { \
443                                SYS_ARCH_DECL_PROTECT(old_level); \
444                                SYS_ARCH_PROTECT(old_level); \
445                                var = val; \
446                                SYS_ARCH_UNPROTECT(old_level); \
447                              } while(0)
448#endif /* SYS_ARCH_SET */
449
450
451#ifdef __cplusplus
452}
453#endif
454
455#endif /* LWIP_HDR_SYS_H */
456