141 lines
6.0 KiB
C
141 lines
6.0 KiB
C
/****************************************************************************************
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| Description: IRQ driver source file
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| File Name: irq.c
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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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| L I C E N S E
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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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| 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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| You should have received a copy of the GNU General Public License along with OpenBLT.
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| If not, see <http://www.gnu.org/licenses/>.
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| A special exception to the GPL is included to allow you to distribute a combined work
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| that includes OpenBLT without being obliged to provide the source code for any
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| proprietary components. The exception text is included at the bottom of the license
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| file <license.html>.
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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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static unsigned long oldInterruptStatus; /* used for global interrupt en/disable */
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static unsigned char interruptNesting = 0; /* used for global interrupt en/disable */
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/****************************************************************************************
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** NAME: IrqGetCPSR
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** PARAMETER: none
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** RETURN VALUE: CPSR value
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** DESCRIPTION: Obtains current value of CPSR CPU register.
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** NOTE: Derived from a sample by R O Software that is Copyright 2004,
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** R O SoftWare, and can be used for hobby or commercial purposes.
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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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** NAME: IrqSetCPSR
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** PARAMETER: CPSR value
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** RETURN VALUE: none
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** DESCRIPTION: Update value of CPSR CPU register.
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** NOTE: Derived from a sample by R O Software that is Copyright 2004,
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** R O SoftWare, and can be used for hobby or commercial purposes.
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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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** NAME: IrqInterruptEnable
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** PARAMETER: none
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** RETURN VALUE: none
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** DESCRIPTION: Enables the generation IRQ interrupts. Typically called once during
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** software startup after completion of the initialization.
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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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** NAME: HwInterruptDisable
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** PARAMETER: none
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** RETURN VALUE: none
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** DESCRIPTION: 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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**
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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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** NAME: IrqInterruptRestore
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** PARAMETER: none
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** RETURN VALUE: none
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** DESCRIPTION: 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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**
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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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