sys.h

00001 /*
00002  * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
00003  * All rights reserved. 
00004  * 
00005  * Redistribution and use in source and binary forms, with or without modification, 
00006  * are permitted provided that the following conditions are met:
00007  *
00008  * 1. Redistributions of source code must retain the above copyright notice,
00009  *    this list of conditions and the following disclaimer.
00010  * 2. Redistributions in binary form must reproduce the above copyright notice,
00011  *    this list of conditions and the following disclaimer in the documentation
00012  *    and/or other materials provided with the distribution.
00013  * 3. The name of the author may not be used to endorse or promote products
00014  *    derived from this software without specific prior written permission. 
00015  *
00016  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
00017  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
00018  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
00019  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
00020  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
00021  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
00022  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
00023  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
00024  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
00025  * OF SUCH DAMAGE.
00026  *
00027  * This file is part of the lwIP TCP/IP stack.
00028  * 
00029  * Author: Adam Dunkels <adam@sics.se>
00030  *
00031  */
00032 #ifndef __LWIP_SYS_H__
00033 #define __LWIP_SYS_H__
00034 
00035 #include "lwip/opt.h"
00036 
00037 #ifdef __cplusplus
00038 extern "C" {
00039 #endif
00040 
00041 #if NO_SYS
00042 
00043 /* For a totally minimal and standalone system, we provide null
00044    definitions of the sys_ functions. */
00045 typedef u8_t sys_sem_t;
00046 typedef u8_t sys_mutex_t;
00047 typedef u8_t sys_mbox_t;
00048 
00049 #define sys_sem_new(s, c) ERR_OK
00050 #define sys_sem_signal(s)
00051 #define sys_sem_wait(s)
00052 #define sys_arch_sem_wait(s,t)
00053 #define sys_sem_free(s)
00054 #define sys_sem_valid(s) 0
00055 #define sys_sem_set_invalid(s)
00056 #define sys_mutex_new(mu) ERR_OK
00057 #define sys_mutex_lock(mu)
00058 #define sys_mutex_unlock(mu)
00059 #define sys_mutex_free(mu)
00060 #define sys_mutex_valid(mu) 0
00061 #define sys_mutex_set_invalid(mu)
00062 #define sys_mbox_new(m, s) ERR_OK
00063 #define sys_mbox_fetch(m,d)
00064 #define sys_mbox_tryfetch(m,d)
00065 #define sys_mbox_post(m,d)
00066 #define sys_mbox_trypost(m,d)
00067 #define sys_mbox_free(m)
00068 #define sys_mbox_valid(m)
00069 #define sys_mbox_set_invalid(m)
00070 
00071 #define sys_thread_new(n,t,a,s,p)
00072 
00073 #define sys_msleep(t)
00074 
00075 #else /* NO_SYS */
00076 
00077 /** Return code for timeouts from sys_arch_mbox_fetch and sys_arch_sem_wait */
00078 #define SYS_ARCH_TIMEOUT 0xffffffffUL
00079 
00080 /** sys_mbox_tryfetch() returns SYS_MBOX_EMPTY if appropriate.
00081  * For now we use the same magic value, but we allow this to change in future.
00082  */
00083 #define SYS_MBOX_EMPTY SYS_ARCH_TIMEOUT 
00084 
00085 #include "lwip/err.h"
00086 #include "arch/sys_arch.h"
00087 
00088 /** Function prototype for thread functions */
00089 typedef void (*lwip_thread_fn)(void *arg);
00090 
00091 /* Function prototypes for functions to be implemented by platform ports
00092    (in sys_arch.c) */
00093 
00094 /* Mutex functions: */
00095 
00096 /** Define LWIP_COMPAT_MUTEX if the port has no mutexes and binary semaphores
00097     should be used instead */
00098 #if LWIP_COMPAT_MUTEX
00099 /* for old ports that don't have mutexes: define them to binary semaphores */
00100 #define sys_mutex_t                   sys_sem_t
00101 #define sys_mutex_new(mutex)          sys_sem_new(mutex, 1)
00102 #define sys_mutex_lock(mutex)         sys_sem_wait(mutex)
00103 #define sys_mutex_unlock(mutex)       sys_sem_signal(mutex)
00104 #define sys_mutex_free(mutex)         sys_sem_free(mutex)
00105 #define sys_mutex_valid(mutex)        sys_sem_valid(mutex)
00106 #define sys_mutex_set_invalid(mutex)  sys_sem_set_invalid(mutex)
00107 
00108 #else /* LWIP_COMPAT_MUTEX */
00109 
00110 /** Create a new mutex
00111  * @param mutex pointer to the mutex to create
00112  * @return a new mutex */
00113 err_t sys_mutex_new(sys_mutex_t *mutex);
00114 /** Lock a mutex
00115  * @param mutex the mutex to lock */
00116 void sys_mutex_lock(sys_mutex_t *mutex);
00117 /** Unlock a mutex
00118  * @param mutex the mutex to unlock */
00119 void sys_mutex_unlock(sys_mutex_t *mutex);
00120 /** Delete a semaphore
00121  * @param mutex the mutex to delete */
00122 void sys_mutex_free(sys_mutex_t *mutex); 
00123 #ifndef sys_mutex_valid
00124 /** Check if a mutex is valid/allocated: return 1 for valid, 0 for invalid */
00125 int sys_mutex_valid(sys_mutex_t *mutex);
00126 #endif
00127 #ifndef sys_mutex_set_invalid
00128 /** Set a mutex invalid so that sys_mutex_valid returns 0 */
00129 void sys_mutex_set_invalid(sys_mutex_t *mutex);
00130 #endif
00131 #endif /* LWIP_COMPAT_MUTEX */
00132 
00133 /* Semaphore functions: */
00134 
00135 /** Create a new semaphore
00136  * @param sem pointer to the semaphore to create
00137  * @param count initial count of the semaphore
00138  * @return ERR_OK if successful, another err_t otherwise */
00139 err_t sys_sem_new(sys_sem_t *sem, u8_t count);
00140 /** Signals a semaphore
00141  * @param sem the semaphore to signal */
00142 void sys_sem_signal(sys_sem_t *sem);
00143 /** Wait for a semaphore for the specified timeout
00144  * @param sem the semaphore to wait for
00145  * @param timeout timeout in milliseconds to wait (0 = wait forever)
00146  * @return time (in milliseconds) waited for the semaphore
00147  *         or SYS_ARCH_TIMEOUT on timeout */
00148 u32_t sys_arch_sem_wait(sys_sem_t *sem, u32_t timeout);
00149 /** Delete a semaphore
00150  * @param sem semaphore to delete */
00151 void sys_sem_free(sys_sem_t *sem);
00152 /** Wait for a semaphore - forever/no timeout */
00153 #define sys_sem_wait(sem)                  sys_arch_sem_wait(sem, 0)
00154 #ifndef sys_sem_valid
00155 /** Check if a sempahore is valid/allocated: return 1 for valid, 0 for invalid */
00156 int sys_sem_valid(sys_sem_t *sem);
00157 #endif
00158 #ifndef sys_sem_set_invalid
00159 /** Set a semaphore invalid so that sys_sem_valid returns 0 */
00160 void sys_sem_set_invalid(sys_sem_t *sem);
00161 #endif
00162 
00163 /* Time functions. */
00164 #ifndef sys_msleep
00165 void sys_msleep(u32_t ms); /* only has a (close to) 1 jiffy resolution. */
00166 #endif
00167 
00168 /* Mailbox functions. */
00169 
00170 /** Create a new mbox of specified size
00171  * @param mbox pointer to the mbox to create
00172  * @param size (miminum) number of messages in this mbox
00173  * @return ERR_OK if successful, another err_t otherwise */
00174 err_t sys_mbox_new(sys_mbox_t *mbox, int size);
00175 /** Post a message to an mbox - may not fail
00176  * -> blocks if full, only used from tasks not from ISR
00177  * @param mbox mbox to posts the message
00178  * @param msg message to post (ATTENTION: can be NULL) */
00179 void sys_mbox_post(sys_mbox_t *mbox, void *msg);
00180 /** Try to post a message to an mbox - may fail if full or ISR
00181  * @param mbox mbox to posts the message
00182  * @param msg message to post (ATTENTION: can be NULL) */
00183 err_t sys_mbox_trypost(sys_mbox_t *mbox, void *msg);
00184 /** Wait for a new message to arrive in the mbox
00185  * @param mbox mbox to get a message from
00186  * @param msg pointer where the message is stored
00187  * @param timeout maximum time (in milliseconds) to wait for a message
00188  * @return time (in milliseconds) waited for a message, may be 0 if not waited
00189            or SYS_ARCH_TIMEOUT on timeout
00190  *         The returned time has to be accurate to prevent timer jitter! */
00191 u32_t sys_arch_mbox_fetch(sys_mbox_t *mbox, void **msg, u32_t timeout);
00192 /* Allow port to override with a macro, e.g. special timout for sys_arch_mbox_fetch() */
00193 #ifndef sys_arch_mbox_tryfetch
00194 /** Wait for a new message to arrive in the mbox
00195  * @param mbox mbox to get a message from
00196  * @param msg pointer where the message is stored
00197  * @param timeout maximum time (in milliseconds) to wait for a message
00198  * @return 0 (milliseconds) if a message has been received
00199  *         or SYS_MBOX_EMPTY if the mailbox is empty */
00200 u32_t sys_arch_mbox_tryfetch(sys_mbox_t *mbox, void **msg);
00201 #endif
00202 /** For now, we map straight to sys_arch implementation. */
00203 #define sys_mbox_tryfetch(mbox, msg) sys_arch_mbox_tryfetch(mbox, msg)
00204 /** Delete an mbox
00205  * @param mbox mbox to delete */
00206 void sys_mbox_free(sys_mbox_t *mbox);
00207 #define sys_mbox_fetch(mbox, msg) sys_arch_mbox_fetch(mbox, msg, 0)
00208 #ifndef sys_mbox_valid
00209 /** Check if an mbox is valid/allocated: return 1 for valid, 0 for invalid */
00210 int sys_mbox_valid(sys_mbox_t *mbox);
00211 #endif
00212 #ifndef sys_mbox_set_invalid
00213 /** Set an mbox invalid so that sys_mbox_valid returns 0 */
00214 void sys_mbox_set_invalid(sys_mbox_t *mbox);
00215 #endif
00216 
00217 /** The only thread function:
00218  * Creates a new thread
00219  * @param name human-readable name for the thread (used for debugging purposes)
00220  * @param thread thread-function
00221  * @param arg parameter passed to 'thread'
00222  * @param stacksize stack size in bytes for the new thread (may be ignored by ports)
00223  * @param prio priority of the new thread (may be ignored by ports) */
00224 sys_thread_t sys_thread_new(const char *name, lwip_thread_fn thread, void *arg, int stacksize, int prio);
00225 
00226 #endif /* NO_SYS */
00227 
00228 /* sys_init() must be called before anthing else. */
00229 void sys_init(void);
00230 
00231 #ifndef sys_jiffies
00232 /** Ticks/jiffies since power up. */
00233 u32_t sys_jiffies(void);
00234 #endif
00235 
00236 /** Returns the current time in milliseconds,
00237  * may be the same as sys_jiffies or at least based on it. */
00238 u32_t sys_now(void);
00239 
00240 /* Critical Region Protection */
00241 /* These functions must be implemented in the sys_arch.c file.
00242    In some implementations they can provide a more light-weight protection
00243    mechanism than using semaphores. Otherwise semaphores can be used for
00244    implementation */
00245 #ifndef SYS_ARCH_PROTECT
00246 /** SYS_LIGHTWEIGHT_PROT
00247  * define SYS_LIGHTWEIGHT_PROT in lwipopts.h if you want inter-task protection
00248  * for certain critical regions during buffer allocation, deallocation and memory
00249  * allocation and deallocation.
00250  */
00251 #if SYS_LIGHTWEIGHT_PROT
00252 
00253 /** SYS_ARCH_DECL_PROTECT
00254  * declare a protection variable. This macro will default to defining a variable of
00255  * type sys_prot_t. If a particular port needs a different implementation, then
00256  * this macro may be defined in sys_arch.h.
00257  */
00258 #define SYS_ARCH_DECL_PROTECT(lev) sys_prot_t lev
00259 /** SYS_ARCH_PROTECT
00260  * Perform a "fast" protect. This could be implemented by
00261  * disabling interrupts for an embedded system or by using a semaphore or
00262  * mutex. The implementation should allow calling SYS_ARCH_PROTECT when
00263  * already protected. The old protection level is returned in the variable
00264  * "lev". This macro will default to calling the sys_arch_protect() function
00265  * which should be implemented in sys_arch.c. If a particular port needs a
00266  * different implementation, then this macro may be defined in sys_arch.h
00267  */
00268 #define SYS_ARCH_PROTECT(lev) lev = sys_arch_protect()
00269 /** SYS_ARCH_UNPROTECT
00270  * Perform a "fast" set of the protection level to "lev". This could be
00271  * implemented by setting the interrupt level to "lev" within the MACRO or by
00272  * using a semaphore or mutex.  This macro will default to calling the
00273  * sys_arch_unprotect() function which should be implemented in
00274  * sys_arch.c. If a particular port needs a different implementation, then
00275  * this macro may be defined in sys_arch.h
00276  */
00277 #define SYS_ARCH_UNPROTECT(lev) sys_arch_unprotect(lev)
00278 sys_prot_t sys_arch_protect(void);
00279 void sys_arch_unprotect(sys_prot_t pval);
00280 
00281 #else
00282 
00283 #define SYS_ARCH_DECL_PROTECT(lev)
00284 #define SYS_ARCH_PROTECT(lev)
00285 #define SYS_ARCH_UNPROTECT(lev)
00286 
00287 #endif /* SYS_LIGHTWEIGHT_PROT */
00288 
00289 #endif /* SYS_ARCH_PROTECT */
00290 
00291 /*
00292  * Macros to set/get and increase/decrease variables in a thread-safe way.
00293  * Use these for accessing variable that are used from more than one thread.
00294  */
00295 
00296 #ifndef SYS_ARCH_INC
00297 #define SYS_ARCH_INC(var, val) do { \
00298                                 SYS_ARCH_DECL_PROTECT(old_level); \
00299                                 SYS_ARCH_PROTECT(old_level); \
00300                                 var += val; \
00301                                 SYS_ARCH_UNPROTECT(old_level); \
00302                               } while(0)
00303 #endif /* SYS_ARCH_INC */
00304 
00305 #ifndef SYS_ARCH_DEC
00306 #define SYS_ARCH_DEC(var, val) do { \
00307                                 SYS_ARCH_DECL_PROTECT(old_level); \
00308                                 SYS_ARCH_PROTECT(old_level); \
00309                                 var -= val; \
00310                                 SYS_ARCH_UNPROTECT(old_level); \
00311                               } while(0)
00312 #endif /* SYS_ARCH_DEC */
00313 
00314 #ifndef SYS_ARCH_GET
00315 #define SYS_ARCH_GET(var, ret) do { \
00316                                 SYS_ARCH_DECL_PROTECT(old_level); \
00317                                 SYS_ARCH_PROTECT(old_level); \
00318                                 ret = var; \
00319                                 SYS_ARCH_UNPROTECT(old_level); \
00320                               } while(0)
00321 #endif /* SYS_ARCH_GET */
00322 
00323 #ifndef SYS_ARCH_SET
00324 #define SYS_ARCH_SET(var, val) do { \
00325                                 SYS_ARCH_DECL_PROTECT(old_level); \
00326                                 SYS_ARCH_PROTECT(old_level); \
00327                                 var = val; \
00328                                 SYS_ARCH_UNPROTECT(old_level); \
00329                               } while(0)
00330 #endif /* SYS_ARCH_SET */
00331 
00332 
00333 #ifdef __cplusplus
00334 }
00335 #endif
00336 
00337 #endif /* __LWIP_SYS_H__ */