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66 lines
1.8 KiB
66 lines
1.8 KiB
/*
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* Copyright (c) 2015, ARM Limited and Contributors. All rights reserved.
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*
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* SPDX-License-Identifier: BSD-3-Clause
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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 != NULL &&
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(ops->clk_mult != 0) &&
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(ops->clk_div != 0) &&
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(ops->get_timer_value != NULL));
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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 != NULL &&
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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 != NULL));
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ops = ops_ptr;
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}
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