83 lines
2.7 KiB
C
83 lines
2.7 KiB
C
/*
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* Copyright (c) 2016, 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 <arch_helpers.h>
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#include <assert.h>
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#include <bl_common.h>
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#include <debug.h>
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#include <delay_timer.h>
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#include <platform.h>
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/* Ticks elapsed in one second by a signal of 1 MHz */
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#define MHZ_TICKS_PER_SEC 1000000
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static timer_ops_t ops;
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static uint32_t get_timer_value(void)
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{
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/*
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* Generic delay timer implementation expects the timer to be a down
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* counter. We apply bitwise NOT operator to the tick values returned
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* by read_cntpct_el0() to simulate the down counter. The value is
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* clipped from 64 to 32 bits.
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*/
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return (uint32_t)(~read_cntpct_el0());
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}
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void generic_delay_timer_init_args(uint32_t mult, uint32_t div)
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{
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ops.get_timer_value = get_timer_value;
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ops.clk_mult = mult;
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ops.clk_div = div;
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timer_init(&ops);
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VERBOSE("Generic delay timer configured with mult=%u and div=%u\n",
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mult, div);
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}
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void generic_delay_timer_init(void)
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{
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/* Value in ticks */
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unsigned int mult = MHZ_TICKS_PER_SEC;
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/* Value in ticks per second (Hz) */
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unsigned int div = plat_get_syscnt_freq2();
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/* Reduce multiplier and divider by dividing them repeatedly by 10 */
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while ((mult % 10 == 0) && (div % 10 == 0)) {
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mult /= 10;
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div /= 10;
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}
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generic_delay_timer_init_args(mult, div);
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}
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