110 lines
3.5 KiB
C
110 lines
3.5 KiB
C
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/* scb.h - ARM CORTEX-M3 System Control Block interface */
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/*
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* Copyright (c) 2013-2014 Wind River Systems, Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1) Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* 2) Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* 3) Neither the name of Wind River Systems nor the names of its contributors
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* may be used to endorse or promote products derived from this software without
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* specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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DESCRIPTION
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Most of the SCB interface consists of simple bit-flipping methods, and is
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implemented as inline functions in scb.h. This module thus contains only data
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definitions and more complex routines, if needed.
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*/
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#include <nanokernel.h>
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#include <nanokernel/cpu.h>
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#include <misc/util.h>
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#define SCB_AIRCR_VECTKEY_EN_W 0x05FA
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/*******************************************************************************
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*
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* _ScbSystemReset - reset the system
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*
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* This routine resets the processor.
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*
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* RETURNS: N/A
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*/
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void _ScbSystemReset(void)
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{
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union __aircr reg;
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reg.val = __scs.scb.aircr.val;
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reg.bit.vectkey = SCB_AIRCR_VECTKEY_EN_W;
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reg.bit.sysresetreq = 1;
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__scs.scb.aircr.val = reg.val;
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}
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/*******************************************************************************
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*
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* _ScbNumPriGroupSet - set the number of priority groups based on the number
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* of exception priorities desired
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*
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* Exception priorities can be divided in priority groups, inside which there is
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* no preemption. The priorities inside a group are only used to decide which
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* exception will run when more than one is ready to be handled.
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*
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* The number of priorities has to be a power of two, from 1 to 128.
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*
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* RETURNS: N/A
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*/
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void _ScbNumPriGroupSet(unsigned int n /* number of priorities */
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)
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{
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unsigned int set;
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union __aircr reg;
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__ASSERT(_IsPowerOfTwo(n) && (n <= 128),
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"invalid number of priorities");
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set = find_first_set(n);
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reg.val = __scs.scb.aircr.val;
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/* num pri bit set prigroup
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* ---------------------------------
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* 1 1 7
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* 2 2 6
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* 4 3 5
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* 8 4 4
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* 16 5 3
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* 32 6 2
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* 64 7 1
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* 128 8 0
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*/
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reg.bit.prigroup = 8 - set;
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reg.bit.vectkey = SCB_AIRCR_VECTKEY_EN_W;
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__scs.scb.aircr.val = reg.val;
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}
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