/** * \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 2005 Develer S.r.l. (http://www.develer.com/) * * --> * * \brief Events handling implementation * * * \author Giovanni Bajo <rasky@develer.com> */ #include "event.h" #include "cfg/cfg_signal.h" #include "cfg/cfg_timer.h" #include <drv/timer.h> /* timer_clock() */ void event_hook_ignore(UNUSED_ARG(Event *, e)) { } void event_hook_softint(Event *e) { e->Ev.Int.func(e->Ev.Int.user_data); } void event_hook_generic(Event *e) { e->Ev.Gen.completed = true; MEMORY_BARRIER; } #if CONFIG_KERN && CONFIG_KERN_SIGNALS void event_hook_signal(Event *e) { sig_post((e)->Ev.Sig.sig_proc, (e)->Ev.Sig.sig_bit); } void event_hook_generic_signal(Event *e) { sig_postSignal(&e->Ev.Sig.sig, e->Ev.Sig.sig_proc, e->Ev.Sig.sig_bit); } /* * Custom event hook to notify the completion of a event monitored via * event_select(). */ static void event_hook_generic_multiple_signal(Event *e) { sig_post(e->Ev.Sig.sig_proc, e->Ev.Sig.sig_bit); } /* * Custom timer hook to notify the timeout of a event_waitTimeout(). */ static void event_hook_generic_timeout_signal(void *arg) { Event *e = (Event *)arg; sig_postSignal(&e->Ev.Sig.sig, e->Ev.Sig.sig_proc, SIG_TIMEOUT); } /* * event_waitTimeout() slow path: this function put the current process to * sleep until the event is notified. The timeout is managed using the custom * timer hook event_hook_generic_timeout_signal(): if the timeout expires the * signal SIG_TIMEOUT is notified via sig_post() to the sigmask embedded in the * event. * * The custom timer hook is required because the default timer's behaviour is * to use the process's sigmask to notify the completion of an event, that is * not suitable for this case, because we're sleeping on the event's sigmask * instead. */ static NOINLINE bool event_waitTimeoutSlowPath(Event *e, ticks_t timeout) { bool ret; e->Ev.Sig.sig_proc = proc_current(); ret = (sig_waitTimeoutSignal(&e->Ev.Sig.sig, EVENT_GENERIC_SIGNAL, timeout, event_hook_generic_timeout_signal, e) & SIG_TIMEOUT) ? false : true; return ret; } bool event_waitTimeout(Event *e, ticks_t timeout) { /* * Fast path: check if the event already happened and return * immediately in this case. */ if (sig_checkSignal(&e->Ev.Sig.sig, EVENT_GENERIC_SIGNAL) == EVENT_GENERIC_SIGNAL) return true; return event_waitTimeoutSlowPath(e, timeout); } /* * event_select() slow path: this function handles the case when any event was * not yet notified, so it takes care of making the current process to sleep on * the list of events, mapping them to a different signal bit and issuing a * call to sig_waitTimeout() using the process's sigmask. */ static NOINLINE int event_selectSlowPath(Event **evs, int n, ticks_t timeout) { sigmask_t mask = (1 << n) - 1; int i; for (i = 0; i < n; i++) { Event *e = evs[i]; /* Map each event to a distinct signal bit */ e->Ev.Sig.sig_proc = proc_current(); e->Ev.Sig.sig_bit = 1 << i; e->action = event_hook_generic_multiple_signal; } IRQ_ENABLE; mask = timeout ? sig_waitTimeout(mask, timeout) : sig_wait(mask); if (mask & SIG_TIMEOUT) return -1; return UINT8_LOG2(mask); } int event_select(Event **evs, int n, ticks_t timeout) { int i; ASSERT(n <= SIG_USER_MAX); IRQ_DISABLE; /* Fast path: check if one of the event already happened */ for (i = 0; i < n; i++) { Event *e = evs[i]; if (__sig_checkSignal(&e->Ev.Sig.sig, EVENT_GENERIC_SIGNAL) == EVENT_GENERIC_SIGNAL) { IRQ_ENABLE; return i; } } /* Otherwise, fallback to the slow path */ return event_selectSlowPath(evs, n, timeout); } #else /* !(CONFIG_KERN && CONFIG_KERN_SIGNALS) */ bool event_waitTimeout(Event *e, ticks_t timeout) { ticks_t end = timer_clock() + timeout; bool ret; while ((ACCESS_SAFE(e->Ev.Gen.completed) == false) || TIMER_AFTER(timer_clock(), end)) cpu_relax(); ret = e->Ev.Gen.completed; e->Ev.Gen.completed = false; MEMORY_BARRIER; return ret; } int event_select(Event **evs, int n, ticks_t timeout) { ticks_t end = timer_clock() + timeout; int i; while (1) { for (i = 0; i < n; i++) { Event *e = evs[i]; if (ACCESS_SAFE(e->Ev.Gen.completed) == true) { e->Ev.Gen.completed = false; MEMORY_BARRIER; return i; } } if (timeout && TIMER_AFTER(timer_clock(), end)) break; cpu_relax(); } return -1; } #endif /* CONFIG_KERN && CONFIG_KERN_SIGNALS */