/** * @file * OS abstraction layer */ /* * Copyright (c) 2001-2004 Swedish Institute of Computer Science. * All rights reserved. * * Redistribution and use in source and binary forms, with or without modification, * are permitted provided that the following conditions are met: * * 1. Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * 3. The name of the author may not be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY * OF SUCH DAMAGE. * * This file is part of the lwIP TCP/IP stack. * * Author: Adam Dunkels */ #ifndef LWIP_HDR_SYS_H #define LWIP_HDR_SYS_H #include "lwip/opt.h" #ifdef __cplusplus extern "C" { #endif #if NO_SYS /* For a totally minimal and standalone system, we provide null definitions of the sys_ functions. */ typedef u8_t sys_sem_t; typedef u8_t sys_mutex_t; typedef u8_t sys_mbox_t; #define sys_sem_new(s, c) ERR_OK #define sys_sem_signal(s) #define sys_sem_wait(s) #define sys_arch_sem_wait(s,t) #define sys_sem_free(s) #define sys_sem_valid(s) 0 #define sys_sem_valid_val(s) 0 #define sys_sem_set_invalid(s) #define sys_sem_set_invalid_val(s) #define sys_mutex_new(mu) ERR_OK #define sys_mutex_lock(mu) #define sys_mutex_unlock(mu) #define sys_mutex_free(mu) #define sys_mutex_valid(mu) 0 #define sys_mutex_set_invalid(mu) #define sys_mbox_new(m, s) ERR_OK #define sys_mbox_fetch(m,d) #define sys_mbox_tryfetch(m,d) #define sys_mbox_post(m,d) #define sys_mbox_trypost(m,d) #define sys_mbox_free(m) #define sys_mbox_valid(m) #define sys_mbox_valid_val(m) #define sys_mbox_set_invalid(m) #define sys_mbox_set_invalid_val(m) #define sys_thread_new(n,t,a,s,p) #define sys_msleep(t) #else /* NO_SYS */ /** Return code for timeouts from sys_arch_mbox_fetch and sys_arch_sem_wait */ #define SYS_ARCH_TIMEOUT 0xffffffffUL /** sys_mbox_tryfetch() returns SYS_MBOX_EMPTY if appropriate. * For now we use the same magic value, but we allow this to change in future. */ #define SYS_MBOX_EMPTY SYS_ARCH_TIMEOUT #include "lwip/err.h" #include "arch/sys_arch.h" /** Function prototype for thread functions */ typedef void (*lwip_thread_fn)(void *arg); /* Function prototypes for functions to be implemented by platform ports (in sys_arch.c) */ /* Mutex functions: */ /** Define LWIP_COMPAT_MUTEX if the port has no mutexes and binary semaphores should be used instead */ #ifndef LWIP_COMPAT_MUTEX #define LWIP_COMPAT_MUTEX 0 #endif #if LWIP_COMPAT_MUTEX /* for old ports that don't have mutexes: define them to binary semaphores */ #define sys_mutex_t sys_sem_t #define sys_mutex_new(mutex) sys_sem_new(mutex, 1) #define sys_mutex_lock(mutex) sys_sem_wait(mutex) #define sys_mutex_unlock(mutex) sys_sem_signal(mutex) #define sys_mutex_free(mutex) sys_sem_free(mutex) #define sys_mutex_valid(mutex) sys_sem_valid(mutex) #define sys_mutex_set_invalid(mutex) sys_sem_set_invalid(mutex) #else /* LWIP_COMPAT_MUTEX */ /** * @ingroup sys_mutex * Create a new mutex. * Note that mutexes are expected to not be taken recursively by the lwIP code, * so both implementation types (recursive or non-recursive) should work. * The mutex is allocated to the memory that 'mutex' * points to (which can be both a pointer or the actual OS structure). * If the mutex has been created, ERR_OK should be returned. Returning any * other error will provide a hint what went wrong, but except for assertions, * no real error handling is implemented. * * @param mutex pointer to the mutex to create * @return ERR_OK if successful, another err_t otherwise */ err_t sys_mutex_new(sys_mutex_t *mutex); /** * @ingroup sys_mutex * Blocks the thread until the mutex can be grabbed. * @param mutex the mutex to lock */ void sys_mutex_lock(sys_mutex_t *mutex); /** * @ingroup sys_mutex * Releases the mutex previously locked through 'sys_mutex_lock()'. * @param mutex the mutex to unlock */ void sys_mutex_unlock(sys_mutex_t *mutex); /** * @ingroup sys_mutex * Deallocates a mutex. * @param mutex the mutex to delete */ void sys_mutex_free(sys_mutex_t *mutex); #ifndef sys_mutex_valid /** * @ingroup sys_mutex * Returns 1 if the mutes is valid, 0 if it is not valid. * When using pointers, a simple way is to check the pointer for != NULL. * When directly using OS structures, implementing this may be more complex. * This may also be a define, in which case the function is not prototyped. */ int sys_mutex_valid(sys_mutex_t *mutex); #endif #ifndef sys_mutex_set_invalid /** * @ingroup sys_mutex * Invalidate a mutex so that sys_mutex_valid() returns 0. * ATTENTION: This does NOT mean that the mutex shall be deallocated: * sys_mutex_free() is always called before calling this function! * This may also be a define, in which case the function is not prototyped. */ void sys_mutex_set_invalid(sys_mutex_t *mutex); #endif #endif /* LWIP_COMPAT_MUTEX */ /* Semaphore functions: */ /** * @ingroup sys_sem * Create a new semaphore * Creates a new semaphore. The semaphore is allocated to the memory that 'sem' * points to (which can be both a pointer or the actual OS structure). * The "count" argument specifies the initial state of the semaphore (which is * either 0 or 1). * If the semaphore has been created, ERR_OK should be returned. Returning any * other error will provide a hint what went wrong, but except for assertions, * no real error handling is implemented. * * @param sem pointer to the semaphore to create * @param count initial count of the semaphore * @return ERR_OK if successful, another err_t otherwise */ err_t sys_sem_new(sys_sem_t *sem, u8_t count); /** * @ingroup sys_sem * Signals a semaphore * @param sem the semaphore to signal */ void sys_sem_signal(sys_sem_t *sem); /** * @ingroup sys_sem * Blocks the thread while waiting for the semaphore to be signaled. If the * "timeout" argument is non-zero, the thread should only be blocked for the * specified time (measured in milliseconds). If the "timeout" argument is zero, * the thread should be blocked until the semaphore is signalled. * * The return value is SYS_ARCH_TIMEOUT if the semaphore wasn't signaled within * the specified time or any other value if it was signaled (with or without * waiting). * Notice that lwIP implements a function with a similar name, * sys_sem_wait(), that uses the sys_arch_sem_wait() function. * * @param sem the semaphore to wait for * @param timeout timeout in milliseconds to wait (0 = wait forever) * @return SYS_ARCH_TIMEOUT on timeout, any other value on success */ u32_t sys_arch_sem_wait(sys_sem_t *sem, u32_t timeout); /** * @ingroup sys_sem * Deallocates a semaphore. * @param sem semaphore to delete */ void sys_sem_free(sys_sem_t *sem); /** Wait for a semaphore - forever/no timeout */ #define sys_sem_wait(sem) sys_arch_sem_wait(sem, 0) #ifndef sys_sem_valid /** * @ingroup sys_sem * Returns 1 if the semaphore is valid, 0 if it is not valid. * When using pointers, a simple way is to check the pointer for != NULL. * When directly using OS structures, implementing this may be more complex. * This may also be a define, in which case the function is not prototyped. */ int sys_sem_valid(sys_sem_t *sem); #endif #ifndef sys_sem_set_invalid /** * @ingroup sys_sem * Invalidate a semaphore so that sys_sem_valid() returns 0. * ATTENTION: This does NOT mean that the semaphore shall be deallocated: * sys_sem_free() is always called before calling this function! * This may also be a define, in which case the function is not prototyped. */ void sys_sem_set_invalid(sys_sem_t *sem); #endif #ifndef sys_sem_valid_val /** * Same as sys_sem_valid() but taking a value, not a pointer */ #define sys_sem_valid_val(sem) sys_sem_valid(&(sem)) #endif #ifndef sys_sem_set_invalid_val /** * Same as sys_sem_set_invalid() but taking a value, not a pointer */ #define sys_sem_set_invalid_val(sem) sys_sem_set_invalid(&(sem)) #endif #ifndef sys_msleep /** * @ingroup sys_misc * Sleep for specified number of ms */ void sys_msleep(u32_t ms); /* only has a (close to) 1 ms resolution. */ #endif /* Mailbox functions. */ /** * @ingroup sys_mbox * Creates an empty mailbox for maximum "size" elements. Elements stored * in mailboxes are pointers. You have to define macros "_MBOX_SIZE" * in your lwipopts.h, or ignore this parameter in your implementation * and use a default size. * If the mailbox has been created, ERR_OK should be returned. Returning any * other error will provide a hint what went wrong, but except for assertions, * no real error handling is implemented. * * @param mbox pointer to the mbox to create * @param size (minimum) number of messages in this mbox * @return ERR_OK if successful, another err_t otherwise */ err_t sys_mbox_new(sys_mbox_t *mbox, int size); /** * @ingroup sys_mbox * Post a message to an mbox - may not fail * -> blocks if full, only to be used from tasks NOT from ISR! * * @param mbox mbox to posts the message * @param msg message to post (ATTENTION: can be NULL) */ void sys_mbox_post(sys_mbox_t *mbox, void *msg); /** * @ingroup sys_mbox * Try to post a message to an mbox - may fail if full. * Can be used from ISR (if the sys arch layer allows this). * Returns ERR_MEM if it is full, else, ERR_OK if the "msg" is posted. * * @param mbox mbox to posts the message * @param msg message to post (ATTENTION: can be NULL) */ err_t sys_mbox_trypost(sys_mbox_t *mbox, void *msg); /** * @ingroup sys_mbox * Try to post a message to an mbox - may fail if full. * To be be used from ISR. * Returns ERR_MEM if it is full, else, ERR_OK if the "msg" is posted. * * @param mbox mbox to posts the message * @param msg message to post (ATTENTION: can be NULL) */ err_t sys_mbox_trypost_fromisr(sys_mbox_t *mbox, void *msg); /** * @ingroup sys_mbox * Blocks the thread until a message arrives in the mailbox, but does * not block the thread longer than "timeout" milliseconds (similar to * the sys_arch_sem_wait() function). If "timeout" is 0, the thread should * be blocked until a message arrives. The "msg" argument is a result * parameter that is set by the function (i.e., by doing "*msg = * ptr"). The "msg" parameter maybe NULL to indicate that the message * should be dropped. * The return values are the same as for the sys_arch_sem_wait() function: * SYS_ARCH_TIMEOUT if there was a timeout, any other value if a messages * is received. * * Note that a function with a similar name, sys_mbox_fetch(), is * implemented by lwIP. * * @param mbox mbox to get a message from * @param msg pointer where the message is stored * @param timeout maximum time (in milliseconds) to wait for a message (0 = wait forever) * @return SYS_ARCH_TIMEOUT on timeout, any other value if a message has been received */ u32_t sys_arch_mbox_fetch(sys_mbox_t *mbox, void **msg, u32_t timeout); /* Allow port to override with a macro, e.g. special timeout for sys_arch_mbox_fetch() */ #ifndef sys_arch_mbox_tryfetch /** * @ingroup sys_mbox * This is similar to sys_arch_mbox_fetch, however if a message is not * present in the mailbox, it immediately returns with the code * SYS_MBOX_EMPTY. On success 0 is returned. * To allow for efficient implementations, this can be defined as a * function-like macro in sys_arch.h instead of a normal function. For * example, a naive implementation could be: * \#define sys_arch_mbox_tryfetch(mbox,msg) sys_arch_mbox_fetch(mbox,msg,1) * although this would introduce unnecessary delays. * * @param mbox mbox to get a message from * @param msg pointer where the message is stored * @return 0 (milliseconds) if a message has been received * or SYS_MBOX_EMPTY if the mailbox is empty */ u32_t sys_arch_mbox_tryfetch(sys_mbox_t *mbox, void **msg); #endif /** * For now, we map straight to sys_arch implementation. */ #define sys_mbox_tryfetch(mbox, msg) sys_arch_mbox_tryfetch(mbox, msg) /** * @ingroup sys_mbox * Deallocates a mailbox. If there are messages still present in the * mailbox when the mailbox is deallocated, it is an indication of a * programming error in lwIP and the developer should be notified. * * @param mbox mbox to delete */ void sys_mbox_free(sys_mbox_t *mbox); #define sys_mbox_fetch(mbox, msg) sys_arch_mbox_fetch(mbox, msg, 0) #ifndef sys_mbox_valid /** * @ingroup sys_mbox * Returns 1 if the mailbox is valid, 0 if it is not valid. * When using pointers, a simple way is to check the pointer for != NULL. * When directly using OS structures, implementing this may be more complex. * This may also be a define, in which case the function is not prototyped. */ int sys_mbox_valid(sys_mbox_t *mbox); #endif #ifndef sys_mbox_set_invalid /** * @ingroup sys_mbox * Invalidate a mailbox so that sys_mbox_valid() returns 0. * ATTENTION: This does NOT mean that the mailbox shall be deallocated: * sys_mbox_free() is always called before calling this function! * This may also be a define, in which case the function is not prototyped. */ void sys_mbox_set_invalid(sys_mbox_t *mbox); #endif #ifndef sys_mbox_valid_val /** * Same as sys_mbox_valid() but taking a value, not a pointer */ #define sys_mbox_valid_val(mbox) sys_mbox_valid(&(mbox)) #endif #ifndef sys_mbox_set_invalid_val /** * Same as sys_mbox_set_invalid() but taking a value, not a pointer */ #define sys_mbox_set_invalid_val(mbox) sys_mbox_set_invalid(&(mbox)) #endif /** * @ingroup sys_misc * The only thread function: * Starts a new thread named "name" with priority "prio" that will begin its * execution in the function "thread()". The "arg" argument will be passed as an * argument to the thread() function. The stack size to used for this thread is * the "stacksize" parameter. The id of the new thread is returned. Both the id * and the priority are system dependent. * ATTENTION: although this function returns a value, it MUST NOT FAIL (ports have to assert this!) * * @param name human-readable name for the thread (used for debugging purposes) * @param thread thread-function * @param arg parameter passed to 'thread' * @param stacksize stack size in bytes for the new thread (may be ignored by ports) * @param prio priority of the new thread (may be ignored by ports) */ sys_thread_t sys_thread_new(const char *name, lwip_thread_fn thread, void *arg, int stacksize, int prio); #endif /* NO_SYS */ /** * @ingroup sys_misc * sys_init() must be called before anything else. * Initialize the sys_arch layer. */ void sys_init(void); #ifndef sys_jiffies /** * Ticks/jiffies since power up. */ u32_t sys_jiffies(void); #endif /** * @ingroup sys_time * Returns the current time in milliseconds, * may be the same as sys_jiffies or at least based on it. * Don't care for wraparound, this is only used for time diffs. * Not implementing this function means you cannot use some modules (e.g. TCP * timestamps, internal timeouts for NO_SYS==1). */ u32_t sys_now(void); /* Critical Region Protection */ /* These functions must be implemented in the sys_arch.c file. In some implementations they can provide a more light-weight protection mechanism than using semaphores. Otherwise semaphores can be used for implementation */ #ifndef SYS_ARCH_PROTECT /** SYS_LIGHTWEIGHT_PROT * define SYS_LIGHTWEIGHT_PROT in lwipopts.h if you want inter-task protection * for certain critical regions during buffer allocation, deallocation and memory * allocation and deallocation. */ #if SYS_LIGHTWEIGHT_PROT /** * @ingroup sys_prot * SYS_ARCH_DECL_PROTECT * declare a protection variable. This macro will default to defining a variable of * type sys_prot_t. If a particular port needs a different implementation, then * this macro may be defined in sys_arch.h. */ #define SYS_ARCH_DECL_PROTECT(lev) sys_prot_t lev /** * @ingroup sys_prot * SYS_ARCH_PROTECT * Perform a "fast" protect. This could be implemented by * disabling interrupts for an embedded system or by using a semaphore or * mutex. The implementation should allow calling SYS_ARCH_PROTECT when * already protected. The old protection level is returned in the variable * "lev". This macro will default to calling the sys_arch_protect() function * which should be implemented in sys_arch.c. If a particular port needs a * different implementation, then this macro may be defined in sys_arch.h */ #define SYS_ARCH_PROTECT(lev) lev = sys_arch_protect() /** * @ingroup sys_prot * SYS_ARCH_UNPROTECT * Perform a "fast" set of the protection level to "lev". This could be * implemented by setting the interrupt level to "lev" within the MACRO or by * using a semaphore or mutex. This macro will default to calling the * sys_arch_unprotect() function which should be implemented in * sys_arch.c. If a particular port needs a different implementation, then * this macro may be defined in sys_arch.h */ #define SYS_ARCH_UNPROTECT(lev) sys_arch_unprotect(lev) sys_prot_t sys_arch_protect(void); void sys_arch_unprotect(sys_prot_t pval); #else #define SYS_ARCH_DECL_PROTECT(lev) #define SYS_ARCH_PROTECT(lev) #define SYS_ARCH_UNPROTECT(lev) #endif /* SYS_LIGHTWEIGHT_PROT */ #endif /* SYS_ARCH_PROTECT */ /* * Macros to set/get and increase/decrease variables in a thread-safe way. * Use these for accessing variable that are used from more than one thread. */ #ifndef SYS_ARCH_INC #define SYS_ARCH_INC(var, val) do { \ SYS_ARCH_DECL_PROTECT(old_level); \ SYS_ARCH_PROTECT(old_level); \ var += val; \ SYS_ARCH_UNPROTECT(old_level); \ } while(0) #endif /* SYS_ARCH_INC */ #ifndef SYS_ARCH_DEC #define SYS_ARCH_DEC(var, val) do { \ SYS_ARCH_DECL_PROTECT(old_level); \ SYS_ARCH_PROTECT(old_level); \ var -= val; \ SYS_ARCH_UNPROTECT(old_level); \ } while(0) #endif /* SYS_ARCH_DEC */ #ifndef SYS_ARCH_GET #define SYS_ARCH_GET(var, ret) do { \ SYS_ARCH_DECL_PROTECT(old_level); \ SYS_ARCH_PROTECT(old_level); \ ret = var; \ SYS_ARCH_UNPROTECT(old_level); \ } while(0) #endif /* SYS_ARCH_GET */ #ifndef SYS_ARCH_SET #define SYS_ARCH_SET(var, val) do { \ SYS_ARCH_DECL_PROTECT(old_level); \ SYS_ARCH_PROTECT(old_level); \ var = val; \ SYS_ARCH_UNPROTECT(old_level); \ } while(0) #endif /* SYS_ARCH_SET */ #ifndef SYS_ARCH_LOCKED #define SYS_ARCH_LOCKED(code) do { \ SYS_ARCH_DECL_PROTECT(old_level); \ SYS_ARCH_PROTECT(old_level); \ code; \ SYS_ARCH_UNPROTECT(old_level); \ } while(0) #endif /* SYS_ARCH_LOCKED */ #ifdef __cplusplus } #endif #endif /* LWIP_HDR_SYS_H */