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Diffstat (limited to 'lwip/src/core/sys.c')
-rw-r--r-- | lwip/src/core/sys.c | 148 |
1 files changed, 148 insertions, 0 deletions
diff --git a/lwip/src/core/sys.c b/lwip/src/core/sys.c new file mode 100644 index 0000000..5f08352 --- /dev/null +++ b/lwip/src/core/sys.c @@ -0,0 +1,148 @@ +/** + * @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 */ |