sys.h

00001 /**
00002  * @file
00003  * OS abstraction layer
00004  */
00005 
00006 /*
00007  * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
00008  * All rights reserved.
00009  *
00010  * Redistribution and use in source and binary forms, with or without modification,
00011  * are permitted provided that the following conditions are met:
00012  *
00013  * 1. Redistributions of source code must retain the above copyright notice,
00014  *    this list of conditions and the following disclaimer.
00015  * 2. Redistributions in binary form must reproduce the above copyright notice,
00016  *    this list of conditions and the following disclaimer in the documentation
00017  *    and/or other materials provided with the distribution.
00018  * 3. The name of the author may not be used to endorse or promote products
00019  *    derived from this software without specific prior written permission.
00020  *
00021  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
00022  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
00023  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
00024  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
00025  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
00026  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
00027  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
00028  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
00029  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
00030  * OF SUCH DAMAGE.
00031  *
00032  * This file is part of the lwIP TCP/IP stack.
00033  *
00034  * Author: Adam Dunkels <adam@sics.se>
00035  */
00036 
00037 /**
00038  * @defgroup sys_layer System abstraction layer
00039  * @ingroup infrastructure
00040  * @verbinclude "sys_arch.txt"
00041  *
00042  * @defgroup sys_os OS abstraction layer
00043  * @ingroup sys_layer
00044  * No need to implement functions in this section in NO_SYS mode.
00045  *
00046  * @defgroup sys_sem Semaphores
00047  * @ingroup sys_os
00048  *
00049  * @defgroup sys_mutex Mutexes
00050  * @ingroup sys_os
00051  * Mutexes are recommended to correctly handle priority inversion,
00052  * especially if you use LWIP_CORE_LOCKING .
00053  *
00054  * @defgroup sys_mbox Mailboxes
00055  * @ingroup sys_os
00056  *
00057  * @defgroup sys_time Time
00058  * @ingroup sys_layer
00059  *
00060  * @defgroup sys_prot Critical sections
00061  * @ingroup sys_layer
00062  * Used to protect short regions of code against concurrent access.
00063  * - Your system is a bare-metal system (probably with an RTOS) 
00064  *   and interrupts are under your control:
00065  *   Implement this as LockInterrupts() / UnlockInterrupts()
00066  * - Your system uses an RTOS with deferred interrupt handling from a 
00067  *   worker thread: Implement as a global mutex or lock/unlock scheduler
00068  * - Your system uses a high-level OS with e.g. POSIX signals:
00069  *   Implement as a global mutex
00070  *
00071  * @defgroup sys_misc Misc
00072  * @ingroup sys_os
00073  */
00074 
00075 #ifndef LWIP_HDR_SYS_H
00076 #define LWIP_HDR_SYS_H
00077 
00078 #include "lwip/opt.h"
00079 
00080 #ifdef __cplusplus
00081 extern "C" {
00082 #endif
00083 
00084 #if NO_SYS
00085 
00086 /* For a totally minimal and standalone system, we provide null
00087    definitions of the sys_ functions. */
00088 typedef u8_t sys_sem_t;
00089 typedef u8_t sys_mutex_t;
00090 typedef u8_t sys_mbox_t;
00091 
00092 #define sys_sem_new(s, c) ERR_OK
00093 #define sys_sem_signal(s)
00094 #define sys_sem_wait(s)
00095 #define sys_arch_sem_wait(s,t)
00096 #define sys_sem_free(s)
00097 #define sys_sem_valid(s) 0
00098 #define sys_sem_valid_val(s) 0
00099 #define sys_sem_set_invalid(s)
00100 #define sys_sem_set_invalid_val(s)
00101 #define sys_mutex_new(mu) ERR_OK
00102 #define sys_mutex_lock(mu)
00103 #define sys_mutex_unlock(mu)
00104 #define sys_mutex_free(mu)
00105 #define sys_mutex_valid(mu) 0
00106 #define sys_mutex_set_invalid(mu)
00107 #define sys_mbox_new(m, s) ERR_OK
00108 #define sys_mbox_fetch(m,d)
00109 #define sys_mbox_tryfetch(m,d)
00110 #define sys_mbox_post(m,d)
00111 #define sys_mbox_trypost(m,d)
00112 #define sys_mbox_free(m)
00113 #define sys_mbox_valid(m)
00114 #define sys_mbox_valid_val(m)
00115 #define sys_mbox_set_invalid(m)
00116 #define sys_mbox_set_invalid_val(m)
00117 
00118 #define sys_thread_new(n,t,a,s,p)
00119 
00120 #define sys_msleep(t)
00121 
00122 #else /* NO_SYS */
00123 
00124 /** Return code for timeouts from sys_arch_mbox_fetch and sys_arch_sem_wait */
00125 #define SYS_ARCH_TIMEOUT 0xffffffffUL
00126 
00127 /** sys_mbox_tryfetch() returns SYS_MBOX_EMPTY if appropriate.
00128  * For now we use the same magic value, but we allow this to change in future.
00129  */
00130 #define SYS_MBOX_EMPTY SYS_ARCH_TIMEOUT
00131 
00132 #include "lwip/err.h"
00133 #include "arch/sys_arch.h"
00134 
00135 /** Function prototype for thread functions */
00136 typedef void (*lwip_thread_fn)(void *arg);
00137 
00138 /* Function prototypes for functions to be implemented by platform ports
00139    (in sys_arch.c) */
00140 
00141 /* Mutex functions: */
00142 
00143 /** Define LWIP_COMPAT_MUTEX if the port has no mutexes and binary semaphores
00144     should be used instead */
00145 #ifndef LWIP_COMPAT_MUTEX
00146 #define LWIP_COMPAT_MUTEX 0
00147 #endif
00148 
00149 #if LWIP_COMPAT_MUTEX
00150 /* for old ports that don't have mutexes: define them to binary semaphores */
00151 #define sys_mutex_t                   sys_sem_t
00152 #define sys_mutex_new(mutex)          sys_sem_new(mutex, 1)
00153 #define sys_mutex_lock(mutex)         sys_sem_wait(mutex)
00154 #define sys_mutex_unlock(mutex)       sys_sem_signal(mutex)
00155 #define sys_mutex_free(mutex)         sys_sem_free(mutex)
00156 #define sys_mutex_valid(mutex)        sys_sem_valid(mutex)
00157 #define sys_mutex_set_invalid(mutex)  sys_sem_set_invalid(mutex)
00158 
00159 #else /* LWIP_COMPAT_MUTEX */
00160 
00161 /**
00162  * @ingroup sys_mutex
00163  * Create a new mutex
00164  * @param mutex pointer to the mutex to create
00165  * @return a new mutex
00166  */
00167 err_t sys_mutex_new(sys_mutex_t *mutex);
00168 /**
00169  * @ingroup sys_mutex
00170  * Lock a mutex
00171  * @param mutex the mutex to lock
00172  */
00173 void sys_mutex_lock(sys_mutex_t *mutex);
00174 /**
00175  * @ingroup sys_mutex
00176  * Unlock a mutex
00177  * @param mutex the mutex to unlock
00178  */
00179 void sys_mutex_unlock(sys_mutex_t *mutex);
00180 /**
00181  * @ingroup sys_mutex
00182  * Delete a semaphore
00183  * @param mutex the mutex to delete
00184  */
00185 void sys_mutex_free(sys_mutex_t *mutex);
00186 #ifndef sys_mutex_valid
00187 /**
00188  * @ingroup sys_mutex
00189  * Check if a mutex is valid/allocated: return 1 for valid, 0 for invalid
00190  */
00191 int sys_mutex_valid(sys_mutex_t *mutex);
00192 #endif
00193 #ifndef sys_mutex_set_invalid
00194 /**
00195  * @ingroup sys_mutex
00196  * Set a mutex invalid so that sys_mutex_valid returns 0
00197  */
00198 void sys_mutex_set_invalid(sys_mutex_t *mutex);
00199 #endif
00200 #endif /* LWIP_COMPAT_MUTEX */
00201 
00202 /* Semaphore functions: */
00203 
00204 /**
00205  * @ingroup sys_sem
00206  * Create a new semaphore
00207  * @param sem pointer to the semaphore to create
00208  * @param count initial count of the semaphore
00209  * @return ERR_OK if successful, another err_t otherwise
00210  */
00211 err_t sys_sem_new(sys_sem_t *sem, u8_t count);
00212 /**
00213  * @ingroup sys_sem
00214  * Signals a semaphore
00215  * @param sem the semaphore to signal
00216  */
00217 void sys_sem_signal(sys_sem_t *sem);
00218 /**
00219  * @ingroup sys_sem
00220  * Wait for a semaphore for the specified timeout
00221  * @param sem the semaphore to wait for
00222  * @param timeout timeout in milliseconds to wait (0 = wait forever)
00223  * @return time (in milliseconds) waited for the semaphore
00224  *         or SYS_ARCH_TIMEOUT on timeout
00225  */
00226 u32_t sys_arch_sem_wait(sys_sem_t *sem, u32_t timeout);
00227 /**
00228  * @ingroup sys_sem
00229  * Delete a semaphore
00230  * @param sem semaphore to delete
00231  */
00232 void sys_sem_free(sys_sem_t *sem);
00233 /** Wait for a semaphore - forever/no timeout */
00234 #define sys_sem_wait(sem)                  sys_arch_sem_wait(sem, 0)
00235 #ifndef sys_sem_valid
00236 /**
00237  * @ingroup sys_sem
00238  * Check if a semaphore is valid/allocated: return 1 for valid, 0 for invalid
00239  */
00240 int sys_sem_valid(sys_sem_t *sem);
00241 #endif
00242 #ifndef sys_sem_set_invalid
00243 /**
00244  * @ingroup sys_sem
00245  * Set a semaphore invalid so that sys_sem_valid returns 0
00246  */
00247 void sys_sem_set_invalid(sys_sem_t *sem);
00248 #endif
00249 #ifndef sys_sem_valid_val
00250 /**
00251  * Same as sys_sem_valid() but taking a value, not a pointer
00252  */
00253 #define sys_sem_valid_val(sem)       sys_sem_valid(&(sem))
00254 #endif
00255 #ifndef sys_sem_set_invalid_val
00256 /**
00257  * Same as sys_sem_set_invalid() but taking a value, not a pointer
00258  */
00259 #define sys_sem_set_invalid_val(sem) sys_sem_set_invalid(&(sem))
00260 #endif
00261 
00262 #ifndef sys_msleep
00263 /**
00264  * @ingroup sys_misc
00265  * Sleep for specified number of ms
00266  */
00267 void sys_msleep(u32_t ms); /* only has a (close to) 1 ms resolution. */
00268 #endif
00269 
00270 /* Mailbox functions. */
00271 
00272 /**
00273  * @ingroup sys_mbox
00274  * Create a new mbox of specified size
00275  * @param mbox pointer to the mbox to create
00276  * @param size (minimum) number of messages in this mbox
00277  * @return ERR_OK if successful, another err_t otherwise
00278  */
00279 err_t sys_mbox_new(sys_mbox_t *mbox, int size);
00280 /**
00281  * @ingroup sys_mbox
00282  * Post a message to an mbox - may not fail
00283  * -> blocks if full, only used from tasks not from ISR
00284  * @param mbox mbox to posts the message
00285  * @param msg message to post (ATTENTION: can be NULL)
00286  */
00287 void sys_mbox_post(sys_mbox_t *mbox, void *msg);
00288 /**
00289  * @ingroup sys_mbox
00290  * Try to post a message to an mbox - may fail if full or ISR
00291  * @param mbox mbox to posts the message
00292  * @param msg message to post (ATTENTION: can be NULL)
00293  */
00294 err_t sys_mbox_trypost(sys_mbox_t *mbox, void *msg);
00295 /**
00296  * @ingroup sys_mbox
00297  * Wait for a new message to arrive in the mbox
00298  * @param mbox mbox to get a message from
00299  * @param msg pointer where the message is stored
00300  * @param timeout maximum time (in milliseconds) to wait for a message (0 = wait forever)
00301  * @return time (in milliseconds) waited for a message, may be 0 if not waited
00302            or SYS_ARCH_TIMEOUT on timeout
00303  *         The returned time has to be accurate to prevent timer jitter!
00304  */
00305 u32_t sys_arch_mbox_fetch(sys_mbox_t *mbox, void **msg, u32_t timeout);
00306 /* Allow port to override with a macro, e.g. special timeout for sys_arch_mbox_fetch() */
00307 #ifndef sys_arch_mbox_tryfetch
00308 /**
00309  * @ingroup sys_mbox
00310  * Wait for a new message to arrive in the mbox
00311  * @param mbox mbox to get a message from
00312  * @param msg pointer where the message is stored
00313  * @return 0 (milliseconds) if a message has been received
00314  *         or SYS_MBOX_EMPTY if the mailbox is empty
00315  */
00316 u32_t sys_arch_mbox_tryfetch(sys_mbox_t *mbox, void **msg);
00317 #endif
00318 /**
00319  * For now, we map straight to sys_arch implementation.
00320  */
00321 #define sys_mbox_tryfetch(mbox, msg) sys_arch_mbox_tryfetch(mbox, msg)
00322 /**
00323  * @ingroup sys_mbox
00324  * Delete an mbox
00325  * @param mbox mbox to delete
00326  */
00327 void sys_mbox_free(sys_mbox_t *mbox);
00328 #define sys_mbox_fetch(mbox, msg) sys_arch_mbox_fetch(mbox, msg, 0)
00329 #ifndef sys_mbox_valid
00330 /**
00331  * @ingroup sys_mbox
00332  * Check if an mbox is valid/allocated: return 1 for valid, 0 for invalid
00333  */
00334 int sys_mbox_valid(sys_mbox_t *mbox);
00335 #endif
00336 #ifndef sys_mbox_set_invalid
00337 /**
00338  * @ingroup sys_mbox
00339  * Set an mbox invalid so that sys_mbox_valid returns 0
00340  */
00341 void sys_mbox_set_invalid(sys_mbox_t *mbox);
00342 #endif
00343 #ifndef sys_mbox_valid_val
00344 /**
00345  * Same as sys_mbox_valid() but taking a value, not a pointer
00346  */
00347 #define sys_mbox_valid_val(mbox)       sys_mbox_valid(&(mbox))
00348 #endif
00349 #ifndef sys_mbox_set_invalid_val
00350 /**
00351  * Same as sys_mbox_set_invalid() but taking a value, not a pointer
00352  */
00353 #define sys_mbox_set_invalid_val(mbox) sys_mbox_set_invalid(&(mbox))
00354 #endif
00355 
00356 
00357 /**
00358  * @ingroup sys_misc
00359  * The only thread function:
00360  * Creates a new thread
00361  * ATTENTION: although this function returns a value, it MUST NOT FAIL (ports have to assert this!)
00362  * @param name human-readable name for the thread (used for debugging purposes)
00363  * @param thread thread-function
00364  * @param arg parameter passed to 'thread'
00365  * @param stacksize stack size in bytes for the new thread (may be ignored by ports)
00366  * @param prio priority of the new thread (may be ignored by ports) */
00367 sys_thread_t sys_thread_new(const char *name, lwip_thread_fn thread, void *arg, int stacksize, int prio);
00368 
00369 #endif /* NO_SYS */
00370 
00371 /* sys_init() must be called before anything else. */
00372 void sys_init(void);
00373 
00374 #ifndef sys_jiffies
00375 /**
00376  * Ticks/jiffies since power up.
00377  */
00378 u32_t sys_jiffies(void);
00379 #endif
00380 
00381 /**
00382  * @ingroup sys_time
00383  * Returns the current time in milliseconds,
00384  * may be the same as sys_jiffies or at least based on it.
00385  */
00386 u32_t sys_now(void);
00387 
00388 /* Critical Region Protection */
00389 /* These functions must be implemented in the sys_arch.c file.
00390    In some implementations they can provide a more light-weight protection
00391    mechanism than using semaphores. Otherwise semaphores can be used for
00392    implementation */
00393 #ifndef SYS_ARCH_PROTECT
00394 /** SYS_LIGHTWEIGHT_PROT
00395  * define SYS_LIGHTWEIGHT_PROT in lwipopts.h if you want inter-task protection
00396  * for certain critical regions during buffer allocation, deallocation and memory
00397  * allocation and deallocation.
00398  */
00399 #if SYS_LIGHTWEIGHT_PROT
00400 
00401 /**
00402  * @ingroup sys_prot
00403  * SYS_ARCH_DECL_PROTECT
00404  * declare a protection variable. This macro will default to defining a variable of
00405  * type sys_prot_t. If a particular port needs a different implementation, then
00406  * this macro may be defined in sys_arch.h.
00407  */
00408 #define SYS_ARCH_DECL_PROTECT(lev) sys_prot_t lev
00409 /**
00410  * @ingroup sys_prot
00411  * SYS_ARCH_PROTECT
00412  * Perform a "fast" protect. This could be implemented by
00413  * disabling interrupts for an embedded system or by using a semaphore or
00414  * mutex. The implementation should allow calling SYS_ARCH_PROTECT when
00415  * already protected. The old protection level is returned in the variable
00416  * "lev". This macro will default to calling the sys_arch_protect() function
00417  * which should be implemented in sys_arch.c. If a particular port needs a
00418  * different implementation, then this macro may be defined in sys_arch.h
00419  */
00420 #define SYS_ARCH_PROTECT(lev) lev = sys_arch_protect()
00421 /**
00422  * @ingroup sys_prot
00423  * SYS_ARCH_UNPROTECT
00424  * Perform a "fast" set of the protection level to "lev". This could be
00425  * implemented by setting the interrupt level to "lev" within the MACRO or by
00426  * using a semaphore or mutex.  This macro will default to calling the
00427  * sys_arch_unprotect() function which should be implemented in
00428  * sys_arch.c. If a particular port needs a different implementation, then
00429  * this macro may be defined in sys_arch.h
00430  */
00431 #define SYS_ARCH_UNPROTECT(lev) sys_arch_unprotect(lev)
00432 sys_prot_t sys_arch_protect(void);
00433 void sys_arch_unprotect(sys_prot_t pval);
00434 
00435 #else
00436 
00437 #define SYS_ARCH_DECL_PROTECT(lev)
00438 #define SYS_ARCH_PROTECT(lev)
00439 #define SYS_ARCH_UNPROTECT(lev)
00440 
00441 #endif /* SYS_LIGHTWEIGHT_PROT */
00442 
00443 #endif /* SYS_ARCH_PROTECT */
00444 
00445 /*
00446  * Macros to set/get and increase/decrease variables in a thread-safe way.
00447  * Use these for accessing variable that are used from more than one thread.
00448  */
00449 
00450 #ifndef SYS_ARCH_INC
00451 #define SYS_ARCH_INC(var, val) do { \
00452                                 SYS_ARCH_DECL_PROTECT(old_level); \
00453                                 SYS_ARCH_PROTECT(old_level); \
00454                                 var += val; \
00455                                 SYS_ARCH_UNPROTECT(old_level); \
00456                               } while(0)
00457 #endif /* SYS_ARCH_INC */
00458 
00459 #ifndef SYS_ARCH_DEC
00460 #define SYS_ARCH_DEC(var, val) do { \
00461                                 SYS_ARCH_DECL_PROTECT(old_level); \
00462                                 SYS_ARCH_PROTECT(old_level); \
00463                                 var -= val; \
00464                                 SYS_ARCH_UNPROTECT(old_level); \
00465                               } while(0)
00466 #endif /* SYS_ARCH_DEC */
00467 
00468 #ifndef SYS_ARCH_GET
00469 #define SYS_ARCH_GET(var, ret) do { \
00470                                 SYS_ARCH_DECL_PROTECT(old_level); \
00471                                 SYS_ARCH_PROTECT(old_level); \
00472                                 ret = var; \
00473                                 SYS_ARCH_UNPROTECT(old_level); \
00474                               } while(0)
00475 #endif /* SYS_ARCH_GET */
00476 
00477 #ifndef SYS_ARCH_SET
00478 #define SYS_ARCH_SET(var, val) do { \
00479                                 SYS_ARCH_DECL_PROTECT(old_level); \
00480                                 SYS_ARCH_PROTECT(old_level); \
00481                                 var = val; \
00482                                 SYS_ARCH_UNPROTECT(old_level); \
00483                               } while(0)
00484 #endif /* SYS_ARCH_SET */
00485 
00486 
00487 #ifdef __cplusplus
00488 }
00489 #endif
00490 
00491 #endif /* LWIP_HDR_SYS_H */