91 lines
3.2 KiB
C
91 lines
3.2 KiB
C
/*
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* Copyright (c) 2015, ARM Limited and Contributors. All rights reserved.
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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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* Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* 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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* Neither the name of ARM nor the names of its contributors may be used
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* to endorse or promote products derived from this software without specific
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* 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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#include <assert.h>
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#include <delay_timer.h>
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#include <platform_def.h>
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/***********************************************************
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* The delay timer implementation
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***********************************************************/
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static const timer_ops_t *ops;
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/***********************************************************
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* Delay for the given number of microseconds. The driver must
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* be initialized before calling this function.
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***********************************************************/
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void udelay(uint32_t usec)
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{
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assert(ops != 0 &&
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(ops->clk_mult != 0) &&
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(ops->clk_div != 0) &&
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(ops->get_timer_value != 0));
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uint32_t start, delta, total_delta;
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assert(usec < UINT32_MAX / ops->clk_div);
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start = ops->get_timer_value();
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total_delta = (usec * ops->clk_div) / ops->clk_mult;
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do {
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/*
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* If the timer value wraps around, the subtraction will
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* overflow and it will still give the correct result.
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*/
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delta = start - ops->get_timer_value(); /* Decreasing counter */
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} while (delta < total_delta);
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}
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/***********************************************************
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* Delay for the given number of milliseconds. The driver must
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* be initialized before calling this function.
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***********************************************************/
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void mdelay(uint32_t msec)
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{
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udelay(msec*1000);
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}
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/***********************************************************
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* Initialize the timer. The fields in the provided timer
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* ops pointer must be valid.
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***********************************************************/
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void timer_init(const timer_ops_t *ops_ptr)
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{
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assert(ops_ptr != 0 &&
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(ops_ptr->clk_mult != 0) &&
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(ops_ptr->clk_div != 0) &&
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(ops_ptr->get_timer_value != 0));
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ops = ops_ptr;
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}
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