177 lines
4.7 KiB
C
177 lines
4.7 KiB
C
/**
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* \file
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* <!--
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* This file is part of BeRTOS.
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*
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* Bertos is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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* As a special exception, you may use this file as part of a free software
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* library without restriction. Specifically, if other files instantiate
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* templates or use macros or inline functions from this file, or you compile
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* this file and link it with other files to produce an executable, this
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* file does not by itself cause the resulting executable to be covered by
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* the GNU General Public License. This exception does not however
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* invalidate any other reasons why the executable file might be covered by
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* the GNU General Public License.
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*
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* Copyright 2007 Develer S.r.l. (http://www.develer.com/)
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*
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* -->
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*
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*
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* \author Francesco Sacchi <batt@develer.com>
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*
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* \brief System IRQ handler for Atmel AT91 ARM7 processors.
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*
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* In Atmel AT91 ARM7TDMI processors, there are various
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* peripheral interrupt sources.
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* In general, every source has its own interrupt vector, so it
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* is possible to assign a specific handler for each interrupt
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* independently.
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* However, there are a few sources called "system sources" that
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* share a common IRQ line and vector, called "system IRQ".
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* So a unique system IRQ dispatcher is implemented here.
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* This module also contains an interface to manage every source
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* independently. It is possible to assign to every system IRQ
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* a specific IRQ handler.
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*
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* \see sysirq_setHandler
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* \see sysirq_setEnable
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*/
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#include "sysirq_at91.h"
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#include <io/arm.h>
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#include <cpu/irq.h>
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#include <cpu/types.h>
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#include <cfg/module.h>
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#include <cfg/macros.h>
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/**
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* Enable/disable the Periodic Interrupt Timer
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* interrupt.
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*/
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INLINE void pit_setEnable(bool enable)
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{
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if (enable)
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PIT_MR |= BV(PITIEN);
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else
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PIT_MR &= ~BV(PITIEN);
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}
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/**
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* Table containing all system irqs.
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*/
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static SysIrq sysirq_tab[] =
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{
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/* PIT, Periodic Interval Timer (System timer)*/
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{
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.enabled = false,
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.setEnable = pit_setEnable,
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.handler = NULL,
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},
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/* TODO: add other system sources here */
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};
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STATIC_ASSERT(countof(sysirq_tab) == SYSIRQ_CNT);
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/**
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* System IRQ dispatcher.
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* This is the entry point for all system IRQs in AT91.
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* This function checks for interrupt enable state of
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* various sources (system timer, etc..) and calls
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* the corresponding handler.
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*
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* \note On AT91SAM7, all system IRQs (timer included) are handled
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* by the sysirq_dispatcher, so we can't differentiate between
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* context-switch and non-context-switch ISR inside this
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* class of IRQs.
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*/
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static DECLARE_ISR_CONTEXT_SWITCH(sysirq_dispatcher)
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{
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unsigned int i;
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for (i = 0; i < countof(sysirq_tab); i++)
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{
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if (sysirq_tab[i].enabled
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&& sysirq_tab[i].handler)
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sysirq_tab[i].handler();
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}
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/* Inform hw that we have served the IRQ */
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AIC_EOICR = 0;
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}
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#define SYSIRQ_PRIORITY 0 ///< default priority for system irqs.
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MOD_DEFINE(sysirq);
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/**
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* Init system IRQ handling.
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* \note all system interrupts are disabled.
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*/
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void sysirq_init(void)
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{
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cpu_flags_t flags;
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IRQ_SAVE_DISABLE(flags);
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/* Disable all system interrupts */
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for (unsigned i = 0; i < countof(sysirq_tab); i++)
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sysirq_tab[i].setEnable(false);
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/* Set the vector. */
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AIC_SVR(SYSC_ID) = sysirq_dispatcher;
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/* Initialize to edge triggered with defined priority. */
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AIC_SMR(SYSC_ID) = AIC_SRCTYPE_INT_EDGE_TRIGGERED | SYSIRQ_PRIORITY;
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/* Clear pending interrupt */
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AIC_ICCR = BV(SYSC_ID);
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/* Enable the system IRQ */
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AIC_IECR = BV(SYSC_ID);
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IRQ_RESTORE(flags);
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MOD_INIT(sysirq);
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}
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/**
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* Helper function used to set handler for system IRQ \a irq.
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*/
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void sysirq_setHandler(sysirq_t irq, sysirq_handler_t handler)
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{
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ASSERT(irq < SYSIRQ_CNT);
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sysirq_tab[irq].handler = handler;
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}
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/**
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* Helper function used to enable/disable system IRQ \a irq.
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*/
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void sysirq_setEnable(sysirq_t irq, bool enable)
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{
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ASSERT(irq < SYSIRQ_CNT);
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sysirq_tab[irq].setEnable(enable);
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sysirq_tab[irq].enabled = enable;
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}
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/**
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* Helper function used to get system IRQ \a irq state.
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*/
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bool sysirq_enabled(sysirq_t irq)
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{
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ASSERT(irq < SYSIRQ_CNT);
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return sysirq_tab[irq].enabled;
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}
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