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/**
* @file
* lwIP Operating System abstraction
*
*/
/*
* 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 <adam@sics.se>
*
*/
/**
* @defgroup sys_layer Porting (system abstraction layer)
* @ingroup lwip
*
* @defgroup sys_os OS abstraction layer
* @ingroup sys_layer
* No need to implement functions in this section in NO_SYS mode.
* The OS-specific code should be implemented in arch/sys_arch.h
* and sys_arch.c of your port.
*
* The operating system emulation layer provides a common interface
* between the lwIP code and the underlying operating system kernel. The
* general idea is that porting lwIP to new architectures requires only
* small changes to a few header files and a new sys_arch
* implementation. It is also possible to do a sys_arch implementation
* that does not rely on any underlying operating system.
*
* The sys_arch provides semaphores, mailboxes and mutexes to lwIP. For the full
* lwIP functionality, multiple threads support can be implemented in the
* sys_arch, but this is not required for the basic lwIP
* functionality. Timer scheduling is implemented in lwIP, but can be implemented
* by the sys_arch port (LWIP_TIMERS_CUSTOM==1).
*
* In addition to the source file providing the functionality of sys_arch,
* the OS emulation layer must provide several header files defining
* macros used throughout lwip. The files required and the macros they
* must define are listed below the sys_arch description.
*
* Since lwIP 1.4.0, semaphore, mutexes and mailbox functions are prototyped in a way that
* allows both using pointers or actual OS structures to be used. This way, memory
* required for such types can be either allocated in place (globally or on the
* stack) or on the heap (allocated internally in the "*_new()" functions).
*
* Note:
* -----
* Be careful with using mem_malloc() in sys_arch. When malloc() refers to
* mem_malloc() you can run into a circular function call problem. In mem.c
* mem_init() tries to allocate a semaphore using mem_malloc, which of course
* can't be performed when sys_arch uses mem_malloc.
*
* @defgroup sys_sem Semaphores
* @ingroup sys_os
* Semaphores can be either counting or binary - lwIP works with both
* kinds.
* Semaphores are represented by the type "sys_sem_t" which is typedef'd
* in the sys_arch.h file. Mailboxes are equivalently represented by the
* type "sys_mbox_t". Mutexes are represented by the type "sys_mutex_t".
* lwIP does not place any restrictions on how these types are represented
* internally.
*
* @defgroup sys_mutex Mutexes
* @ingroup sys_os
* Mutexes are recommended to correctly handle priority inversion,
* especially if you use LWIP_CORE_LOCKING .
*
* @defgroup sys_mbox Mailboxes
* @ingroup sys_os
* Mailboxes should be implemented as a queue which allows multiple messages
* to be posted (implementing as a rendez-vous point where only one message can be
* posted at a time can have a highly negative impact on performance). A message
* in a mailbox is just a pointer, nothing more.
*
* @defgroup sys_time Time
* @ingroup sys_layer
*
* @defgroup sys_prot Critical sections
* @ingroup sys_layer
* Used to protect short regions of code against concurrent access.
* - Your system is a bare-metal system (probably with an RTOS)
* and interrupts are under your control:
* Implement this as LockInterrupts() / UnlockInterrupts()
* - Your system uses an RTOS with deferred interrupt handling from a
* worker thread: Implement as a global mutex or lock/unlock scheduler
* - Your system uses a high-level OS with e.g. POSIX signals:
* Implement as a global mutex
*
* @defgroup sys_misc Misc
* @ingroup sys_os
*/
#include "lwip/opt.h"
#include "lwip/sys.h"
/* Most of the functions defined in sys.h must be implemented in the
* architecture-dependent file sys_arch.c */
#if !NO_SYS
#ifndef sys_msleep
/**
* Sleep for some ms. Timeouts are NOT processed while sleeping.
*
* @param ms number of milliseconds to sleep
*/
void
sys_msleep(u32_t ms)
{
if (ms > 0) {
sys_sem_t delaysem;
err_t err = sys_sem_new(&delaysem, 0);
if (err == ERR_OK) {
sys_arch_sem_wait(&delaysem, ms);
sys_sem_free(&delaysem);
}
}
}
#endif /* sys_msleep */
#endif /* !NO_SYS */
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