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 #ifndef LWIP_HDR_SYS_H
00038 #define LWIP_HDR_SYS_H
00039 
00040 #include "lwip/opt.h"
00041 
00042 #ifdef __cplusplus
00043 extern "C" {
00044 #endif
00045 
00046 #if NO_SYS
00047 
00048 /* For a totally minimal and standalone system, we provide null
00049    definitions of the sys_ functions. */
00050 typedef u8_t sys_sem_t;
00051 typedef u8_t sys_mutex_t;
00052 typedef u8_t sys_mbox_t;
00053 
00054 #define sys_sem_new(s, c) ERR_OK
00055 #define sys_sem_signal(s)
00056 #define sys_sem_wait(s)
00057 #define sys_arch_sem_wait(s,t)
00058 #define sys_sem_free(s)
00059 #define sys_sem_valid(s) 0
00060 #define sys_sem_valid_val(s) 0
00061 #define sys_sem_set_invalid(s)
00062 #define sys_sem_set_invalid_val(s)
00063 #define sys_mutex_new(mu) ERR_OK
00064 #define sys_mutex_lock(mu)
00065 #define sys_mutex_unlock(mu)
00066 #define sys_mutex_free(mu)
00067 #define sys_mutex_valid(mu) 0
00068 #define sys_mutex_set_invalid(mu)
00069 #define sys_mbox_new(m, s) ERR_OK
00070 #define sys_mbox_fetch(m,d)
00071 #define sys_mbox_tryfetch(m,d)
00072 #define sys_mbox_post(m,d)
00073 #define sys_mbox_trypost(m,d)
00074 #define sys_mbox_free(m)
00075 #define sys_mbox_valid(m)
00076 #define sys_mbox_valid_val(m)
00077 #define sys_mbox_set_invalid(m)
00078 #define sys_mbox_set_invalid_val(m)
00079 
00080 #define sys_thread_new(n,t,a,s,p)
00081 
00082 #define sys_msleep(t)
00083 
00084 #else /* NO_SYS */
00085 
00086 /** Return code for timeouts from sys_arch_mbox_fetch and sys_arch_sem_wait */
00087 #define SYS_ARCH_TIMEOUT 0xffffffffUL
00088 
00089 /** sys_mbox_tryfetch() returns SYS_MBOX_EMPTY if appropriate.
00090  * For now we use the same magic value, but we allow this to change in future.
00091  */
00092 #define SYS_MBOX_EMPTY SYS_ARCH_TIMEOUT
00093 
00094 #include "lwip/err.h"
00095 #include "arch/sys_arch.h"
00096 
00097 /** Function prototype for thread functions */
00098 typedef void (*lwip_thread_fn)(void *arg);
00099 
00100 /* Function prototypes for functions to be implemented by platform ports
00101    (in sys_arch.c) */
00102 
00103 /* Mutex functions: */
00104 
00105 /** Define LWIP_COMPAT_MUTEX if the port has no mutexes and binary semaphores
00106     should be used instead */
00107 #ifndef LWIP_COMPAT_MUTEX
00108 #define LWIP_COMPAT_MUTEX 0
00109 #endif
00110 
00111 #if LWIP_COMPAT_MUTEX
00112 /* for old ports that don't have mutexes: define them to binary semaphores */
00113 #define sys_mutex_t                   sys_sem_t
00114 #define sys_mutex_new(mutex)          sys_sem_new(mutex, 1)
00115 #define sys_mutex_lock(mutex)         sys_sem_wait(mutex)
00116 #define sys_mutex_unlock(mutex)       sys_sem_signal(mutex)
00117 #define sys_mutex_free(mutex)         sys_sem_free(mutex)
00118 #define sys_mutex_valid(mutex)        sys_sem_valid(mutex)
00119 #define sys_mutex_set_invalid(mutex)  sys_sem_set_invalid(mutex)
00120 
00121 #else /* LWIP_COMPAT_MUTEX */
00122 
00123 /**
00124  * @ingroup sys_mutex
00125  * Create a new mutex.
00126  * Note that mutexes are expected to not be taken recursively by the lwIP code,
00127  * so both implementation types (recursive or non-recursive) should work.
00128  * @param mutex pointer to the mutex to create
00129  * @return ERR_OK if successful, another err_t otherwise
00130  */
00131 err_t sys_mutex_new(sys_mutex_t *mutex);
00132 /**
00133  * @ingroup sys_mutex
00134  * Lock a mutex
00135  * @param mutex the mutex to lock
00136  */
00137 void sys_mutex_lock(sys_mutex_t *mutex);
00138 /**
00139  * @ingroup sys_mutex
00140  * Unlock a mutex
00141  * @param mutex the mutex to unlock
00142  */
00143 void sys_mutex_unlock(sys_mutex_t *mutex);
00144 /**
00145  * @ingroup sys_mutex
00146  * Delete a semaphore
00147  * @param mutex the mutex to delete
00148  */
00149 void sys_mutex_free(sys_mutex_t *mutex);
00150 #ifndef sys_mutex_valid
00151 /**
00152  * @ingroup sys_mutex
00153  * Check if a mutex is valid/allocated: return 1 for valid, 0 for invalid
00154  */
00155 int sys_mutex_valid(sys_mutex_t *mutex);
00156 #endif
00157 #ifndef sys_mutex_set_invalid
00158 /**
00159  * @ingroup sys_mutex
00160  * Set a mutex invalid so that sys_mutex_valid returns 0
00161  */
00162 void sys_mutex_set_invalid(sys_mutex_t *mutex);
00163 #endif
00164 #endif /* LWIP_COMPAT_MUTEX */
00165 
00166 /* Semaphore functions: */
00167 
00168 /**
00169  * @ingroup sys_sem
00170  * Create a new semaphore
00171  * @param sem pointer to the semaphore to create
00172  * @param count initial count of the semaphore
00173  * @return ERR_OK if successful, another err_t otherwise
00174  */
00175 err_t sys_sem_new(sys_sem_t *sem, u8_t count);
00176 /**
00177  * @ingroup sys_sem
00178  * Signals a semaphore
00179  * @param sem the semaphore to signal
00180  */
00181 void sys_sem_signal(sys_sem_t *sem);
00182 /**
00183  * @ingroup sys_sem
00184  * Wait for a semaphore for the specified timeout
00185  * @param sem the semaphore to wait for
00186  * @param timeout timeout in milliseconds to wait (0 = wait forever)
00187  * @return time (in milliseconds) waited for the semaphore
00188  *         or SYS_ARCH_TIMEOUT on timeout
00189  */
00190 u32_t sys_arch_sem_wait(sys_sem_t *sem, u32_t timeout);
00191 /**
00192  * @ingroup sys_sem
00193  * Delete a semaphore
00194  * @param sem semaphore to delete
00195  */
00196 void sys_sem_free(sys_sem_t *sem);
00197 /** Wait for a semaphore - forever/no timeout */
00198 #define sys_sem_wait(sem)                  sys_arch_sem_wait(sem, 0)
00199 #ifndef sys_sem_valid
00200 /**
00201  * @ingroup sys_sem
00202  * Check if a semaphore is valid/allocated: return 1 for valid, 0 for invalid
00203  */
00204 int sys_sem_valid(sys_sem_t *sem);
00205 #endif
00206 #ifndef sys_sem_set_invalid
00207 /**
00208  * @ingroup sys_sem
00209  * Set a semaphore invalid so that sys_sem_valid returns 0
00210  */
00211 void sys_sem_set_invalid(sys_sem_t *sem);
00212 #endif
00213 #ifndef sys_sem_valid_val
00214 /**
00215  * Same as sys_sem_valid() but taking a value, not a pointer
00216  */
00217 #define sys_sem_valid_val(sem)       sys_sem_valid(&(sem))
00218 #endif
00219 #ifndef sys_sem_set_invalid_val
00220 /**
00221  * Same as sys_sem_set_invalid() but taking a value, not a pointer
00222  */
00223 #define sys_sem_set_invalid_val(sem) sys_sem_set_invalid(&(sem))
00224 #endif
00225 
00226 #ifndef sys_msleep
00227 /**
00228  * @ingroup sys_misc
00229  * Sleep for specified number of ms
00230  */
00231 void sys_msleep(u32_t ms); /* only has a (close to) 1 ms resolution. */
00232 #endif
00233 
00234 /* Mailbox functions. */
00235 
00236 /**
00237  * @ingroup sys_mbox
00238  * Create a new mbox of specified size
00239  * @param mbox pointer to the mbox to create
00240  * @param size (minimum) number of messages in this mbox
00241  * @return ERR_OK if successful, another err_t otherwise
00242  */
00243 err_t sys_mbox_new(sys_mbox_t *mbox, int size);
00244 /**
00245  * @ingroup sys_mbox
00246  * Post a message to an mbox - may not fail
00247  * -> blocks if full, only used from tasks not from ISR
00248  * @param mbox mbox to posts the message
00249  * @param msg message to post (ATTENTION: can be NULL)
00250  */
00251 void sys_mbox_post(sys_mbox_t *mbox, void *msg);
00252 /**
00253  * @ingroup sys_mbox
00254  * Try to post a message to an mbox - may fail if full or ISR
00255  * @param mbox mbox to posts the message
00256  * @param msg message to post (ATTENTION: can be NULL)
00257  */
00258 err_t sys_mbox_trypost(sys_mbox_t *mbox, void *msg);
00259 /**
00260  * @ingroup sys_mbox
00261  * Wait for a new message to arrive in the mbox
00262  * @param mbox mbox to get a message from
00263  * @param msg pointer where the message is stored
00264  * @param timeout maximum time (in milliseconds) to wait for a message (0 = wait forever)
00265  * @return time (in milliseconds) waited for a message, may be 0 if not waited
00266            or SYS_ARCH_TIMEOUT on timeout
00267  *         The returned time has to be accurate to prevent timer jitter!
00268  */
00269 u32_t sys_arch_mbox_fetch(sys_mbox_t *mbox, void **msg, u32_t timeout);
00270 /* Allow port to override with a macro, e.g. special timeout for sys_arch_mbox_fetch() */
00271 #ifndef sys_arch_mbox_tryfetch
00272 /**
00273  * @ingroup sys_mbox
00274  * Wait for a new message to arrive in the mbox
00275  * @param mbox mbox to get a message from
00276  * @param msg pointer where the message is stored
00277  * @return 0 (milliseconds) if a message has been received
00278  *         or SYS_MBOX_EMPTY if the mailbox is empty
00279  */
00280 u32_t sys_arch_mbox_tryfetch(sys_mbox_t *mbox, void **msg);
00281 #endif
00282 /**
00283  * For now, we map straight to sys_arch implementation.
00284  */
00285 #define sys_mbox_tryfetch(mbox, msg) sys_arch_mbox_tryfetch(mbox, msg)
00286 /**
00287  * @ingroup sys_mbox
00288  * Delete an mbox
00289  * @param mbox mbox to delete
00290  */
00291 void sys_mbox_free(sys_mbox_t *mbox);
00292 #define sys_mbox_fetch(mbox, msg) sys_arch_mbox_fetch(mbox, msg, 0)
00293 #ifndef sys_mbox_valid
00294 /**
00295  * @ingroup sys_mbox
00296  * Check if an mbox is valid/allocated: return 1 for valid, 0 for invalid
00297  */
00298 int sys_mbox_valid(sys_mbox_t *mbox);
00299 #endif
00300 #ifndef sys_mbox_set_invalid
00301 /**
00302  * @ingroup sys_mbox
00303  * Set an mbox invalid so that sys_mbox_valid returns 0
00304  */
00305 void sys_mbox_set_invalid(sys_mbox_t *mbox);
00306 #endif
00307 #ifndef sys_mbox_valid_val
00308 /**
00309  * Same as sys_mbox_valid() but taking a value, not a pointer
00310  */
00311 #define sys_mbox_valid_val(mbox)       sys_mbox_valid(&(mbox))
00312 #endif
00313 #ifndef sys_mbox_set_invalid_val
00314 /**
00315  * Same as sys_mbox_set_invalid() but taking a value, not a pointer
00316  */
00317 #define sys_mbox_set_invalid_val(mbox) sys_mbox_set_invalid(&(mbox))
00318 #endif
00319 
00320 
00321 /**
00322  * @ingroup sys_misc
00323  * The only thread function:
00324  * Creates a new thread
00325  * ATTENTION: although this function returns a value, it MUST NOT FAIL (ports have to assert this!)
00326  * @param name human-readable name for the thread (used for debugging purposes)
00327  * @param thread thread-function
00328  * @param arg parameter passed to 'thread'
00329  * @param stacksize stack size in bytes for the new thread (may be ignored by ports)
00330  * @param prio priority of the new thread (may be ignored by ports) */
00331 sys_thread_t sys_thread_new(const char *name, lwip_thread_fn thread, void *arg, int stacksize, int prio);
00332 
00333 #endif /* NO_SYS */
00334 
00335 /* sys_init() must be called before anything else. */
00336 void sys_init(void);
00337 
00338 #ifndef sys_jiffies
00339 /**
00340  * Ticks/jiffies since power up.
00341  */
00342 u32_t sys_jiffies(void);
00343 #endif
00344 
00345 /**
00346  * @ingroup sys_time
00347  * Returns the current time in milliseconds,
00348  * may be the same as sys_jiffies or at least based on it.
00349  */
00350 u32_t sys_now(void);
00351 
00352 /* Critical Region Protection */
00353 /* These functions must be implemented in the sys_arch.c file.
00354    In some implementations they can provide a more light-weight protection
00355    mechanism than using semaphores. Otherwise semaphores can be used for
00356    implementation */
00357 #ifndef SYS_ARCH_PROTECT
00358 /** SYS_LIGHTWEIGHT_PROT
00359  * define SYS_LIGHTWEIGHT_PROT in lwipopts.h if you want inter-task protection
00360  * for certain critical regions during buffer allocation, deallocation and memory
00361  * allocation and deallocation.
00362  */
00363 #if SYS_LIGHTWEIGHT_PROT
00364 
00365 /**
00366  * @ingroup sys_prot
00367  * SYS_ARCH_DECL_PROTECT
00368  * declare a protection variable. This macro will default to defining a variable of
00369  * type sys_prot_t. If a particular port needs a different implementation, then
00370  * this macro may be defined in sys_arch.h.
00371  */
00372 #define SYS_ARCH_DECL_PROTECT(lev) sys_prot_t lev
00373 /**
00374  * @ingroup sys_prot
00375  * SYS_ARCH_PROTECT
00376  * Perform a "fast" protect. This could be implemented by
00377  * disabling interrupts for an embedded system or by using a semaphore or
00378  * mutex. The implementation should allow calling SYS_ARCH_PROTECT when
00379  * already protected. The old protection level is returned in the variable
00380  * "lev". This macro will default to calling the sys_arch_protect() function
00381  * which should be implemented in sys_arch.c. If a particular port needs a
00382  * different implementation, then this macro may be defined in sys_arch.h
00383  */
00384 #define SYS_ARCH_PROTECT(lev) lev = sys_arch_protect()
00385 /**
00386  * @ingroup sys_prot
00387  * SYS_ARCH_UNPROTECT
00388  * Perform a "fast" set of the protection level to "lev". This could be
00389  * implemented by setting the interrupt level to "lev" within the MACRO or by
00390  * using a semaphore or mutex.  This macro will default to calling the
00391  * sys_arch_unprotect() function which should be implemented in
00392  * sys_arch.c. If a particular port needs a different implementation, then
00393  * this macro may be defined in sys_arch.h
00394  */
00395 #define SYS_ARCH_UNPROTECT(lev) sys_arch_unprotect(lev)
00396 sys_prot_t sys_arch_protect(void);
00397 void sys_arch_unprotect(sys_prot_t pval);
00398 
00399 #else
00400 
00401 #define SYS_ARCH_DECL_PROTECT(lev)
00402 #define SYS_ARCH_PROTECT(lev)
00403 #define SYS_ARCH_UNPROTECT(lev)
00404 
00405 #endif /* SYS_LIGHTWEIGHT_PROT */
00406 
00407 #endif /* SYS_ARCH_PROTECT */
00408 
00409 /*
00410  * Macros to set/get and increase/decrease variables in a thread-safe way.
00411  * Use these for accessing variable that are used from more than one thread.
00412  */
00413 
00414 #ifndef SYS_ARCH_INC
00415 #define SYS_ARCH_INC(var, val) do { \
00416                                 SYS_ARCH_DECL_PROTECT(old_level); \
00417                                 SYS_ARCH_PROTECT(old_level); \
00418                                 var += val; \
00419                                 SYS_ARCH_UNPROTECT(old_level); \
00420                               } while(0)
00421 #endif /* SYS_ARCH_INC */
00422 
00423 #ifndef SYS_ARCH_DEC
00424 #define SYS_ARCH_DEC(var, val) do { \
00425                                 SYS_ARCH_DECL_PROTECT(old_level); \
00426                                 SYS_ARCH_PROTECT(old_level); \
00427                                 var -= val; \
00428                                 SYS_ARCH_UNPROTECT(old_level); \
00429                               } while(0)
00430 #endif /* SYS_ARCH_DEC */
00431 
00432 #ifndef SYS_ARCH_GET
00433 #define SYS_ARCH_GET(var, ret) do { \
00434                                 SYS_ARCH_DECL_PROTECT(old_level); \
00435                                 SYS_ARCH_PROTECT(old_level); \
00436                                 ret = var; \
00437                                 SYS_ARCH_UNPROTECT(old_level); \
00438                               } while(0)
00439 #endif /* SYS_ARCH_GET */
00440 
00441 #ifndef SYS_ARCH_SET
00442 #define SYS_ARCH_SET(var, val) do { \
00443                                 SYS_ARCH_DECL_PROTECT(old_level); \
00444                                 SYS_ARCH_PROTECT(old_level); \
00445                                 var = val; \
00446                                 SYS_ARCH_UNPROTECT(old_level); \
00447                               } while(0)
00448 #endif /* SYS_ARCH_SET */
00449 
00450 
00451 #ifdef __cplusplus
00452 }
00453 #endif
00454 
00455 #endif /* LWIP_HDR_SYS_H */