-/*!
+/**
* \file
* <!--
+ * This file is part of BeRTOS.
+ *
+ * Bertos is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * As a special exception, you may use this file as part of a free software
+ * library without restriction. Specifically, if other files instantiate
+ * templates or use macros or inline functions from this file, or you compile
+ * this file and link it with other files to produce an executable, this
+ * file does not by itself cause the resulting executable to be covered by
+ * the GNU General Public License. This exception does not however
+ * invalidate any other reasons why the executable file might be covered by
+ * the GNU General Public License.
+ *
* Copyright 2004 Develer S.r.l. (http://www.develer.com/)
* Copyright 1999, 2000, 2001 Bernardo Innocenti <bernie@develer.com>
- * This file is part of DevLib - See README.devlib for information.
+ *
* -->
*
* \brief IPC signals implementation.
* signals. POSIX signals are usually executed synchronously, like
* software interrupts.
*
+ * Signals are very low overhead. Using them exclusively to wait
+ * for multiple asynchronous events results in very simple dispatch
+ * logic with low processor and resource usage.
+ *
+ * The "event" module is a higher-level interface that can optionally
+ * deliver signals to processes. Messages provide even higher-level
+ * IPC services built on signals. Semaphore arbitration is also
+ * implemented using signals.
+ *
* In this implementation, each process has a limited set of signal
* bits (usually 32) and can wait for multiple signals at the same
* time using sig_wait(). Signals can also be polled using sig_check(),
* delivered twice before the process can notice.
*
* Any execution context, including an interrupt handler, can deliver
- * a signal to a process using sig_signal(). Multiple distinct signals
+ * a signal to a process using sig_signal(). Multiple independent signals
* may be delivered at once with a single invocation of sig_signal(),
* although this is rarely useful.
*
+ * \section signal_allocation Signal Allocation
+ *
* There's no hardcoded mapping of specific events to signal bits.
* The meaning of a particular signal bit is defined by an agreement
* between the delivering entity and the receiving process.
- * For instance, a terminal driver may be written to deliver
+ * For instance, a terminal driver may be designed to deliver
* a signal bit called SIG_INT when it reads the CTRL-C sequence
* from the keyboard, and a process may react to it by quitting.
*
- * The SIG_SINGLE bit is reserved for a special purpose (this is
- * more a suggestion than a constraint). When a process wants
- * wait for a single event on the fly, it needs not allocate a
- * free signal from its pool. Instead, SIG_SINGLE can be used
- *
- * The "event" module is a higher-level interface that can optionally
- * deliver signals to processes. Messages provide even higher-level
- * IPC services built on signals. Semaphore arbitration is also
- * implemented using signals.
- *
- * Signals are very low overhead. Using them exclusively to wait
- * for multiple asynchronous events results in very simple dispatch
- * logic with low processor and resource usage.
+ * \section sig_single SIG_SINGLE
*
+ * The SIG_SINGLE bit is reserved as a convenient shortcut in those
+ * simple scenarios where a process needs to wait on just one event
+ * synchronously. By using SIG_SINGLE, there's no need to allocate
+ * a specific signal from the free pool. The constraints for safely
+ * accessing SIG_SINGLE are:
+ * - The process MUST sig_wait() exclusively on SIG_SINGLE
+ * - SIG_SIGNAL MUST NOT be left pending after use (sig_wait() will reset
+ * it automatically)
+ * - Do not sleep between starting the asynchronous task that will fire
+ * SIG_SINGLE, and the call to sig_wait().
+ * - Do not call system functions that may implicitly sleep, such as
+ * timer_delayTickes().
*
* \version $Id$
*
* \author Bernardo Innocenti <bernie@develer.com>
*/
-/*#*
- *#* $Log$
- *#* Revision 1.12 2005/11/04 16:20:02 bernie
- *#* Fix reference to README.devlib in header.
- *#*
- *#* Revision 1.11 2005/04/11 19:10:28 bernie
- *#* Include top-level headers from cfg/ subdir.
- *#*
- *#* Revision 1.10 2004/12/13 12:07:06 bernie
- *#* DISABLE_IRQSAVE/ENABLE_IRQRESTORE: Convert to IRQ_SAVE_DISABLE/IRQ_RESTORE.
- *#*
- *#* Revision 1.9 2004/12/08 08:57:35 bernie
- *#* Rename sigset_t to sigmask_t.
- *#*
- *#* Revision 1.8 2004/09/14 21:06:44 bernie
- *#* Use debug.h instead of kdebug.h.
- *#*
- *#* Revision 1.7 2004/08/25 14:12:09 rasky
- *#* Aggiornato il comment block dei log RCS
- *#*
- *#* Revision 1.6 2004/08/14 19:37:57 rasky
- *#* Merge da SC: macros.h, pool.h, BIT_CHANGE, nome dei processi, etc.
- *#*
- *#* Revision 1.5 2004/08/04 21:50:33 bernie
- *#* Add extensive documentation.
- *#*
- *#* Revision 1.4 2004/07/30 14:30:27 rasky
- *#* Resa la sig_signal interrupt safe (con il nuovo scheduler IRQ-safe)
- *#* Rimossa event_doIntr (ora inutile) e semplificata la logica delle macro con funzioni inline
- *#*
- *#* Revision 1.3 2004/07/30 14:24:16 rasky
- *#* Task switching con salvataggio perfetto stato di interrupt (SR)
- *#* Kernel monitor per dump informazioni su stack dei processi
- *#*
- *#* Revision 1.2 2004/06/03 11:27:09 bernie
- *#* Add dual-license information.
- *#*
- *#* Revision 1.1 2004/05/23 17:27:00 bernie
- *#* Import kern/ subdirectory.
- *#*
- *#*/
-
#include "signal.h"
-#include "proc.h"
-#include "proc_p.h"
-#include "hw.h"
+
#include <cfg/debug.h>
+#include <drv/timer.h>
+#include <kern/proc.h>
+#include <kern/proc_p.h>
+
#if CONFIG_KERN_SIGNALS
-/*!
+/**
* Check if any of the signals in \a sigs has occurred and clear them.
- * Return the signals that have occurred.
+ * \return the signals that have occurred.
*/
sigmask_t sig_check(sigmask_t sigs)
{
}
-/*!
+/**
* Sleep until any of the signals in \a sigs occurs.
- * Return the signal(s) that have awaked the process.
+ * \return the signal(s) that have awoken the process.
*/
sigmask_t sig_wait(sigmask_t sigs)
{
return result;
}
+/**
+ * Sleep until any of the signals in \a sigs or \a timeout ticks elapse.
+ * If the timeout elapse a SIG_TIMEOUT is added to the received signal(s).
+ * \return the signal(s) that have awoken the process.
+ * \note Caller must check return value to check which signal awoke the process.
+ */
+sigmask_t sig_waitTimeout(sigmask_t sigs, ticks_t timeout)
+{
+ Timer t;
+ sigmask_t res;
+ cpuflags_t flags;
+
+ ASSERT(!sig_check(SIG_TIMEOUT));
+ ASSERT(!(sigs & SIG_TIMEOUT));
+ /* IRQ are needed to run timer */
+ ASSERT(IRQ_ENABLED());
+
+ timer_set_event_signal(&t, proc_current(), SIG_TIMEOUT);
+ timer_setDelay(&t, timeout);
+ timer_add(&t);
+ res = sig_wait(SIG_TIMEOUT | sigs);
+
+ IRQ_SAVE_DISABLE(flags);
+ /* Remove timer if sigs occur before timer signal */
+ if (!(res & SIG_TIMEOUT) && !sig_check(SIG_TIMEOUT))
+ timer_abort(&t);
+ IRQ_RESTORE(flags);
+ return res;
+}
+
-/*!
+/**
* Send the signals \a sigs to the process \a proc.
- * The process will be awaken if it was waiting for any of them.
+ * The process will be awoken if it was waiting for any of them.
*
* \note This call is interrupt safe.
*/
/* Set the signals */
proc->sig_recv |= sigs;
- /* Check if process needs to be awaken */
+ /* Check if process needs to be awoken */
if (proc->sig_recv & proc->sig_wait)
{
/* Wake up process and enqueue in ready list */
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