src/core/sys.c (LwIP)

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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 */