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diff --git a/bertos/cpu/arm/drv/sysirq_at91.c b/bertos/cpu/arm/drv/sysirq_at91.c
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+/**
+ * \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 2007 Develer S.r.l. (http://www.develer.com/)
+ *
+ * -->
+ *
+ * \version $Id$
+ *
+ * \author Francesco Sacchi <batt@develer.com>
+ *
+ * \brief System IRQ handler for Atmel AT91 ARM7 processors.
+ *
+ * In Atmel AT91 ARM7TDMI processors, there are various
+ * peripheral interrupt sources.
+ * In general, every source has its own interrupt vector, so it
+ * is possible to assign a specific handler for each interrupt
+ * independently.
+ * However, there are a few sources called "system sources" that
+ * share a common IRQ line and vector, called "system IRQ".
+ * So a unique system IRQ dispatcher is implemented here.
+ * This module also contains an interface to manage every source
+ * independently. It is possible to assign to every system IRQ
+ * a specific IRQ handler.
+ *
+ * \see sysirq_setHandler
+ * \see sysirq_setEnable
+ */
+
+#include "sysirq_at91.h"
+#include <io/arm.h>
+#include <cpu/irq.h>
+#include <cpu/types.h>
+#include <cfg/module.h>
+#include <cfg/macros.h>
+
+/**
+ * Enable/disable the Periodic Interrupt Timer
+ * interrupt.
+ */
+INLINE void pit_setEnable(bool enable)
+{
+	if (enable)
+		PIT_MR |= BV(PITIEN);
+	else
+		PIT_MR &= ~BV(PITIEN);
+}
+
+/**
+ * Table containing all system irqs.
+ */
+static SysIrq sysirq_tab[] =
+{
+	/* PIT, Periodic Interval Timer (System timer)*/
+	{
+		.enabled = false,
+		.setEnable = pit_setEnable,
+		.handler = NULL,
+	},
+	/* TODO: add other system sources here */
+};
+
+STATIC_ASSERT(countof(sysirq_tab) == SYSIRQ_CNT);
+
+/**
+ * System IRQ dispatcher.
+ * This is the entry point for all system IRQs in AT91.
+ * This function checks for interrupt enable state of
+ * various sources (system timer, etc..) and calls
+ * the corresponding handler.
+ */
+static void sysirq_dispatcher(void) __attribute__ ((interrupt));
+static void sysirq_dispatcher(void)
+{
+	for (unsigned i = 0; i < countof(sysirq_tab); i++)
+	{
+		if (sysirq_tab[i].enabled
+		 && sysirq_tab[i].handler)
+			sysirq_tab[i].handler();
+	}
+
+	/* Inform hw that we have served the IRQ */
+	AIC_EOICR = 0;
+}
+
+#define SYSIRQ_PRIORITY 0 ///< default priority for system irqs.
+
+
+MOD_DEFINE(sysirq);
+
+/**
+ * Init system IRQ handling.
+ * \note all system interrupts are disabled.
+ */
+void sysirq_init(void)
+{
+	cpuflags_t flags;
+	IRQ_SAVE_DISABLE(flags);
+
+	/* Disable all system interrupts */
+	for (unsigned i = 0; i < countof(sysirq_tab); i++)
+		sysirq_tab[i].setEnable(false);
+
+	/* Set the vector. */
+	AIC_SVR(SYSC_ID) = sysirq_dispatcher;
+	/* Initialize to edge triggered with defined priority. */
+	AIC_SMR(SYSC_ID) = AIC_SRCTYPE_INT_EDGE_TRIGGERED | SYSIRQ_PRIORITY;
+	/* Clear pending interrupt */
+	AIC_ICCR = BV(SYSC_ID);
+	/* Enable the system IRQ */
+	AIC_IECR = BV(SYSC_ID);
+
+	IRQ_RESTORE(flags);
+	MOD_INIT(sysirq);
+}
+
+
+/**
+ * Helper function used to set handler for system IRQ \a irq.
+ */
+void sysirq_setHandler(sysirq_t irq, sysirq_handler_t handler)
+{
+	ASSERT(irq < SYSIRQ_CNT);
+	sysirq_tab[irq].handler = handler;
+}
+
+/**
+ * Helper function used to enable/disable system IRQ \a irq.
+ */
+void sysirq_setEnable(sysirq_t irq, bool enable)
+{
+	ASSERT(irq < SYSIRQ_CNT);
+
+	sysirq_tab[irq].setEnable(enable);
+	sysirq_tab[irq].enabled = enable;
+}
+
+/**
+ * Helper function used to get system IRQ \a irq state.
+ */
+bool sysirq_enabled(sysirq_t irq)
+{
+	ASSERT(irq < SYSIRQ_CNT);
+
+	return sysirq_tab[irq].enabled;
+}