131 lines
5.6 KiB
C
131 lines
5.6 KiB
C
/************************************************************************************//**
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* \file Demo\ARM7_LPC2000_Olimex_LPC_L2294_Crossworks\Prog\irq.c
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* \brief IRQ driver source file.
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* \ingroup Prog_ARM7_LPC2000_Olimex_LPC_L2294_Crossworks
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* \internal
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*----------------------------------------------------------------------------------------
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* C O P Y R I G H T
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*----------------------------------------------------------------------------------------
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* Copyright (c) 2011 by Feaser http://www.feaser.com All rights reserved
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*
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*----------------------------------------------------------------------------------------
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* L I C E N S E
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*----------------------------------------------------------------------------------------
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* This file is part of OpenBLT. OpenBLT is free software: you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as published by the Free
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* Software Foundation, either version 3 of the License, or (at your option) any later
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* version.
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*
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* OpenBLT is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
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* without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
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* PURPOSE. See the GNU General Public License for more details.
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*
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* You have received a copy of the GNU General Public License along with OpenBLT. It
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* should be located in ".\Doc\license.html". If not, contact Feaser to obtain a copy.
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*
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* \endinternal
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****************************************************************************************/
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/****************************************************************************************
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* Include files
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****************************************************************************************/
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#include "header.h" /* generic header */
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/****************************************************************************************
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* Local data definitions
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****************************************************************************************/
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/** \brief Interrupt status before disabling. Used for global interrupt en/disable. */
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static unsigned long oldInterruptStatus;
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/** \brief Interrupt nesting counter. Used for global interrupt en/disable. */
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static unsigned char interruptNesting = 0;
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/************************************************************************************//**
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** \brief Obtains current value of CPSR CPU register. Derived from a sample by R O
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** Software that is Copyright 2004, R O SoftWare, and can be used for hobby
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** or commercial purposes.
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** \return CPSR value.
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**
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****************************************************************************************/
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static unsigned long IrqGetCPSR(void)
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{
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unsigned long retval;
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__asm__ volatile (" mrs %0, cpsr" : "=r" (retval) : /* no inputs */ );
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return retval;
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} /*** end of IrqGetCPSR ***/
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/************************************************************************************//**
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** \brief Update value of CPSR CPU register. Derived from a sample by R O
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** Software that is Copyright 2004, R O SoftWare, and can be used for hobby
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** or commercial purposes.
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** \param val CPSR value.
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** \return none.
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**
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****************************************************************************************/
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static void IrqSetCPSR(unsigned long val)
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{
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__asm__ volatile (" msr cpsr, %0" : /* no outputs */ : "r" (val) );
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} /*** end of IrqSetCPSR ***/
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/************************************************************************************//**
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** \brief Enables the generation IRQ interrupts. Typically called once during
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** software startup after completion of the initialization.
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** \return none.
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**
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****************************************************************************************/
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void IrqInterruptEnable(void)
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{
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unsigned _cpsr;
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_cpsr = IrqGetCPSR();
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IrqSetCPSR(_cpsr & ~0x00000080);
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} /*** end of IrqInterruptEnable ***/
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/************************************************************************************//**
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** \brief Disables the generation IRQ interrupts and stores information on
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** whether or not the interrupts were already disabled before explicitly
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** disabling them with this function. Normally used as a pair together
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** with IrqInterruptRestore during a critical section.
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** \return none.
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**
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****************************************************************************************/
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void IrqInterruptDisable(void)
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{
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unsigned long _cpsr;
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if (interruptNesting == 0)
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{
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_cpsr = IrqGetCPSR();
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IrqSetCPSR(_cpsr | 0x00000080);
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oldInterruptStatus = _cpsr;
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}
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interruptNesting++;
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} /*** end of IrqInterruptDisable ***/
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/************************************************************************************//**
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** \brief Restore the generation IRQ interrupts to the setting it had prior to
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** calling IrqInterruptDisable. Normally used as a pair together with
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** IrqInterruptDisable during a critical section.
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** \return none.
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**
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****************************************************************************************/
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void IrqInterruptRestore(void)
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{
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unsigned _cpsr;
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interruptNesting--;
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if (interruptNesting == 0)
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{
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_cpsr = IrqGetCPSR();
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IrqSetCPSR((_cpsr & ~0x00000080) | (oldInterruptStatus & 0x00000080));
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}
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} /*** end of IrqInterruptRestore ***/
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/*********************************** end of irq.c **************************************/
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