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_mbox_t;
00047 struct sys_timeo {u8_t dummy;};
00048 
00049 #define sys_init()
00050 #define sys_timeout(m,h,a)
00051 #define sys_untimeout(m,a)
00052 #define sys_sem_new(c) c
00053 #define sys_sem_signal(s)
00054 #define sys_sem_wait(s)
00055 #define sys_sem_wait_timeout(s,t)
00056 #define sys_arch_sem_wait(s,t)
00057 #define sys_sem_free(s)
00058 #define sys_mbox_new(s) 0
00059 #define sys_mbox_fetch(m,d)
00060 #define sys_mbox_tryfetch(m,d)
00061 #define sys_mbox_post(m,d)
00062 #define sys_mbox_trypost(m,d)
00063 #define sys_mbox_free(m)
00064 
00065 #define sys_thread_new(n,t,a,s,p)
00066 
00067 #else /* NO_SYS */
00068 
00069 /** Return code for timeouts from sys_arch_mbox_fetch and sys_arch_sem_wait */
00070 #define SYS_ARCH_TIMEOUT 0xffffffffUL
00071 
00072 /* sys_mbox_tryfetch returns SYS_MBOX_EMPTY if appropriate.
00073  * For now we use the same magic value, but we allow this to change in future.
00074  */
00075 #define SYS_MBOX_EMPTY SYS_ARCH_TIMEOUT 
00076 
00077 #include "lwip/err.h"
00078 #include "arch/sys_arch.h"
00079 
00080 typedef void (* sys_timeout_handler)(void *arg);
00081 
00082 struct sys_timeo {
00083   struct sys_timeo *next;
00084   u32_t time;
00085   sys_timeout_handler h;
00086   void *arg;
00087 };
00088 
00089 struct sys_timeouts {
00090   struct sys_timeo *next;
00091 };
00092 
00093 /* sys_init() must be called before anthing else. */
00094 void sys_init(void);
00095 
00096 /*
00097  * sys_timeout():
00098  *
00099  * Schedule a timeout a specified amount of milliseconds in the
00100  * future. When the timeout occurs, the specified timeout handler will
00101  * be called. The handler will be passed the "arg" argument when
00102  * called.
00103  *
00104  */
00105 void sys_timeout(u32_t msecs, sys_timeout_handler h, void *arg);
00106 void sys_untimeout(sys_timeout_handler h, void *arg);
00107 struct sys_timeouts *sys_arch_timeouts(void);
00108 
00109 /* Semaphore functions. */
00110 sys_sem_t sys_sem_new(u8_t count);
00111 void sys_sem_signal(sys_sem_t sem);
00112 u32_t sys_arch_sem_wait(sys_sem_t sem, u32_t timeout);
00113 void sys_sem_free(sys_sem_t sem);
00114 void sys_sem_wait(sys_sem_t sem);
00115 int sys_sem_wait_timeout(sys_sem_t sem, u32_t timeout);
00116 
00117 /* Time functions. */
00118 #ifndef sys_msleep
00119 void sys_msleep(u32_t ms); /* only has a (close to) 1 jiffy resolution. */
00120 #endif
00121 #ifndef sys_jiffies
00122 u32_t sys_jiffies(void); /* since power up. */
00123 #endif
00124 
00125 /* Mailbox functions. */
00126 sys_mbox_t sys_mbox_new(int size);
00127 void sys_mbox_post(sys_mbox_t mbox, void *msg);
00128 err_t sys_mbox_trypost(sys_mbox_t mbox, void *msg);
00129 u32_t sys_arch_mbox_fetch(sys_mbox_t mbox, void **msg, u32_t timeout);
00130 #ifndef sys_arch_mbox_tryfetch /* Allow port to override with a macro */
00131 u32_t sys_arch_mbox_tryfetch(sys_mbox_t mbox, void **msg);
00132 #endif
00133 /* For now, we map straight to sys_arch implementation. */
00134 #define sys_mbox_tryfetch(mbox, msg) sys_arch_mbox_tryfetch(mbox, msg)
00135 void sys_mbox_free(sys_mbox_t mbox);
00136 void sys_mbox_fetch(sys_mbox_t mbox, void **msg);
00137 
00138 /* Thread functions. */
00139 sys_thread_t sys_thread_new(char *name, void (* thread)(void *arg), void *arg, int stacksize, int prio);
00140 
00141 #endif /* NO_SYS */
00142 
00143 /** Returns the current time in milliseconds. */
00144 u32_t sys_now(void);
00145 
00146 /* Critical Region Protection */
00147 /* These functions must be implemented in the sys_arch.c file.
00148    In some implementations they can provide a more light-weight protection
00149    mechanism than using semaphores. Otherwise semaphores can be used for
00150    implementation */
00151 #ifndef SYS_ARCH_PROTECT
00152 /** SYS_LIGHTWEIGHT_PROT
00153  * define SYS_LIGHTWEIGHT_PROT in lwipopts.h if you want inter-task protection
00154  * for certain critical regions during buffer allocation, deallocation and memory
00155  * allocation and deallocation.
00156  */
00157 #if SYS_LIGHTWEIGHT_PROT
00158 
00159 /** SYS_ARCH_DECL_PROTECT
00160  * declare a protection variable. This macro will default to defining a variable of
00161  * type sys_prot_t. If a particular port needs a different implementation, then
00162  * this macro may be defined in sys_arch.h.
00163  */
00164 #define SYS_ARCH_DECL_PROTECT(lev) sys_prot_t lev
00165 /** SYS_ARCH_PROTECT
00166  * Perform a "fast" protect. This could be implemented by
00167  * disabling interrupts for an embedded system or by using a semaphore or
00168  * mutex. The implementation should allow calling SYS_ARCH_PROTECT when
00169  * already protected. The old protection level is returned in the variable
00170  * "lev". This macro will default to calling the sys_arch_protect() function
00171  * which should be implemented in sys_arch.c. If a particular port needs a
00172  * different implementation, then this macro may be defined in sys_arch.h
00173  */
00174 #define SYS_ARCH_PROTECT(lev) lev = sys_arch_protect()
00175 /** SYS_ARCH_UNPROTECT
00176  * Perform a "fast" set of the protection level to "lev". This could be
00177  * implemented by setting the interrupt level to "lev" within the MACRO or by
00178  * using a semaphore or mutex.  This macro will default to calling the
00179  * sys_arch_unprotect() function which should be implemented in
00180  * sys_arch.c. If a particular port needs a different implementation, then
00181  * this macro may be defined in sys_arch.h
00182  */
00183 #define SYS_ARCH_UNPROTECT(lev) sys_arch_unprotect(lev)
00184 sys_prot_t sys_arch_protect(void);
00185 void sys_arch_unprotect(sys_prot_t pval);
00186 
00187 #else
00188 
00189 #define SYS_ARCH_DECL_PROTECT(lev)
00190 #define SYS_ARCH_PROTECT(lev)
00191 #define SYS_ARCH_UNPROTECT(lev)
00192 
00193 #endif /* SYS_LIGHTWEIGHT_PROT */
00194 
00195 #endif /* SYS_ARCH_PROTECT */
00196 
00197 /*
00198  * Macros to set/get and increase/decrease variables in a thread-safe way.
00199  * Use these for accessing variable that are used from more than one thread.
00200  */
00201 
00202 #ifndef SYS_ARCH_INC
00203 #define SYS_ARCH_INC(var, val) do { \
00204                                 SYS_ARCH_DECL_PROTECT(old_level); \
00205                                 SYS_ARCH_PROTECT(old_level); \
00206                                 var += val; \
00207                                 SYS_ARCH_UNPROTECT(old_level); \
00208                               } while(0)
00209 #endif /* SYS_ARCH_INC */
00210 
00211 #ifndef SYS_ARCH_DEC
00212 #define SYS_ARCH_DEC(var, val) do { \
00213                                 SYS_ARCH_DECL_PROTECT(old_level); \
00214                                 SYS_ARCH_PROTECT(old_level); \
00215                                 var -= val; \
00216                                 SYS_ARCH_UNPROTECT(old_level); \
00217                               } while(0)
00218 #endif /* SYS_ARCH_DEC */
00219 
00220 #ifndef SYS_ARCH_GET
00221 #define SYS_ARCH_GET(var, ret) do { \
00222                                 SYS_ARCH_DECL_PROTECT(old_level); \
00223                                 SYS_ARCH_PROTECT(old_level); \
00224                                 ret = var; \
00225                                 SYS_ARCH_UNPROTECT(old_level); \
00226                               } while(0)
00227 #endif /* SYS_ARCH_GET */
00228 
00229 #ifndef SYS_ARCH_SET
00230 #define SYS_ARCH_SET(var, val) do { \
00231                                 SYS_ARCH_DECL_PROTECT(old_level); \
00232                                 SYS_ARCH_PROTECT(old_level); \
00233                                 var = val; \
00234                                 SYS_ARCH_UNPROTECT(old_level); \
00235                               } while(0)
00236 #endif /* SYS_ARCH_SET */
00237 
00238 
00239 #ifdef __cplusplus
00240 }
00241 #endif
00242 
00243 #endif /* __LWIP_SYS_H__ */